xgettext: Add support for generic XML files

* autogen.sh (GNULIB_MODULES_TOOLS_FOR_SRC): Add trim module.
* gettext-tools/src/locating-rule.h: New file.
* gettext-tools/src/locating-rule.c: New file.
* gettext-tools/src/its.h: New file.
* gettext-tools/src/its.c: New file.
* gettext-tools/src/xgettext.c: Include "locating-rule.h" and "its.h".
(its_locators): New variable.
(long_options): Add --itstool option.
(extract_from_xml_file): New function.
(main): Handle --itstool option.
(usage): Document --itstool option.
* gettext-tools/src/Makefile.am (noinst_HEADERS): Add locating-rule.h
and its.h.
(libgettextsrc_la_CPPFLAGS): Add $(INCXML).
(libgettextsrc_la_SOURCES): Add locating-rule.c and its.c.
* gettext-tools/Makefile.am (SUBDIRS): Add its directory.
* gettext-tools/configure.ac: Output its/Makefile.
* gettext-tools/doc/gettext.texi (Preparing ITS Rules): New section.
* gettext-tools/doc/xgettext.texi: Mention --itstool option.
* gettext-tools/tests/Makefile.am (TESTS): Add new tests.
* gettext-tools/tests/xgettext-its-1: New file
* gettext-tools/tests/init-env.in: Set GETTEXTDATADIR for ITS tests.

15 files changed, 3010 insertions, 34 deletions

diff --git a/autogen.sh b/autogen.sh
index 3a301e4..d498be8 100755
--- a/autogen.sh
+++ b/autogen.sh
@@ -245,6 +245,7 @@ if ! $skip_gnulib; then
       sys_stat
       sys_time
       term-styled-ostream
+      trim
       unictype/ctype-space
       unilbrk/ulc-width-linebreaks
       uniname/uniname
diff --git a/gettext-tools/Makefile.am b/gettext-tools/Makefile.am
index e118f21..567b7ca 100644
--- a/gettext-tools/Makefile.am
+++ b/gettext-tools/Makefile.am
@@ -19,7 +19,7 @@
 AUTOMAKE_OPTIONS = 1.5 gnu no-dependencies
 ACLOCAL_AMFLAGS = -I m4 -I ../gettext-runtime/m4 -I ../m4 -I gnulib-m4 -I libgrep/gnulib-m4 -I libgettextpo/gnulib-m4
 
-SUBDIRS = doc intl gnulib-lib libgrep src libgettextpo po projects styles misc man m4 tests gnulib-tests examples
+SUBDIRS = doc intl gnulib-lib libgrep src libgettextpo po projects styles misc man m4 tests gnulib-tests examples its
 
 EXTRA_DIST = misc/DISCLAIM
 MOSTLYCLEANFILES = core *.stackdump
diff --git a/gettext-tools/configure.ac b/gettext-tools/configure.ac
index 920eeb6..fdf156e 100644
--- a/gettext-tools/configure.ac
+++ b/gettext-tools/configure.ac
@@ -461,6 +461,11 @@ AC_SUBST([ARCHIVE_FORMAT])
 ARCHIVE_VERSION=0.19.6
 AC_SUBST([ARCHIVE_VERSION])
 
+PACKAGE_SUFFIX="-$ARCHIVE_VERSION"
+AC_SUBST([PACKAGE_SUFFIX])
+AC_DEFINE_UNQUOTED(PACKAGE_SUFFIX, "$PACKAGE_SUFFIX",
+  [Define to the suffix of this package])
+
 dnl Check for tools needed for formatting the documentation.
 ac_aux_dir_abs=`cd $ac_aux_dir && pwd`
 AC_PATH_PROG([DVIPS], [dvips], [$ac_aux_dir_abs/missing dvips])
@@ -519,6 +524,8 @@ AC_CONFIG_FILES([intl/Makefile:../gettext-runtime/intl/Makefile.in], [
   mv intl/Makefile.tmp intl/Makefile
   ])
 
+AC_CONFIG_FILES([its/Makefile])
+
 AC_CONFIG_FILES([gnulib-lib/Makefile])
 
 AC_CONFIG_FILES([libgrep/Makefile])
diff --git a/gettext-tools/doc/gettext.texi b/gettext-tools/doc/gettext.texi
index ed01f87..7e81a9c 100644
--- a/gettext-tools/doc/gettext.texi
+++ b/gettext-tools/doc/gettext.texi
@@ -470,6 +470,7 @@ Internationalizable Data
 * Glade::                       Glade - GNOME user interface description
 * GSettings::                   GSettings - GNOME user configuration schema
 * AppData::                     AppData - freedesktop.org application description
+* Preparing ITS Rules::         Preparing Rules for XML Internationalization
 
 Concluding Remarks
 
@@ -12155,6 +12156,7 @@ using GNU gettext.
 * Glade::                       Glade - GNOME user interface description
 * GSettings::                   GSettings - GNOME user configuration schema
 * AppData::                     AppData - freedesktop.org application description
+* Preparing ITS Rules::  Preparing Rules for XML Internationalization
 @end menu
 
 @node POT, RST, List of Data Formats, List of Data Formats
@@ -12214,7 +12216,7 @@ glib2
 @code{xgettext}, @code{intltool-extract}
 @end table
 
-@node AppData,  , GSettings, List of Data Formats
+@node AppData, Preparing ITS Rules, GSettings, List of Data Formats
 @subsection AppData - freedesktop.org application description
 
 @table @asis
@@ -12228,6 +12230,139 @@ appdata-tools, appstream, libappstream-glib, libappstream-glib-builder
 @code{xgettext}, @code{intltool-extract}, @code{itstool}
 @end table
 
+@menu
+@end menu
+
+@node Preparing ITS Rules,  , AppData, List of Data Formats
+@subsection Preparing Rules for XML Internationalization
+@cindex preparing rules for XML translation
+
+Marking translatable strings in an XML file is done through a separate
+"rule" file, making use of the Internationalization Tag Set standard
+(ITS, @uref{http://www.w3.org/TR/its20/}).  The currently supported ITS
+data categories are: @samp{Translate}, @samp{Localization Note},
+@samp{Elements Within Text}, and @samp{Preserve Space}.  In addition to
+them, @code{xgettext} also recognizes the following extended data
+categories:
+
+@table @samp
+@item Context
+
+This data category associates @code{msgctxt} to the extracted text.  In
+the global rule, the @code{contextRule} element contains the following:
+
+@itemize
+@item
+A required @code{selector} attribute.  It contains an absolute selector
+that selects the nodes to which this rule applies.
+
+@item
+A required @code{contextPointer} attribute that contains a relative
+selector pointing to a node that holds the @code{msgctxt} value.
+
+@item
+An optional @code{textPointer} attribute that contains a relative
+selector pointing to a node that holds the @code{msgid} value.
+@end itemize
+
+@item Escape Special Characters
+
+This data category indicates whether the special XML characters
+(@code{<}, @code{>}, @code{&}, @code{"}) are escaped with entity
+reference.  In the global rule, the @code{escapeRule} element contains
+the following:
+
+@itemize
+@item
+A required @code{selector} attribute.  It contains an absolute selector
+that selects the nodes to which this rule applies.
+
+@item
+A required @code{escape} attribute with the value @code{yes} or @code{no}.
+@end itemize
+
+@item Extended Preserve Space
+
+This data category extends the standard @samp{Preserve Space} data
+category with the additional value @samp{trim}.  The value means to
+remove the leading and trailing whitespaces of the content, but not to
+normalize whitespaces in the middle.
+
+@end table
+
+All those extended data categories can only be expressed with global
+rules, and the rule elements have to have the
+@code{https://www.gnu.org/s/gettext/ns/its/extensions/1.0} namespace.
+
+Given the following XML document in a file @file{messages.xml}:
+
+@example
+<?xml version="1.0"?>
+<messages>
+  <message>
+    <p>A translatable string</p>
+  </message>
+  <message>
+    <p translatable="no">A non-translatable string</p>
+  </message>
+</messages>
+@end example
+
+To extract the first text content ("A translatable string"), but not the
+second ("A non-translatable string"), the following ITS rules can be used:
+
+@example
+<?xml version="1.0"?>
+<its:rules xmlns:its="http://www.w3.org/2005/11/its" version="1.0">
+  <its:translateRule selector="/messages" translate="no"/>
+  <its:translateRule selector="//message/p" translate="yes"/>
+
+  <!-- If 'p' has an attribute 'translatable' with the value 'no', then
+       the content is not translatable.  -->
+  <its:translateRule selector="//message/p[@@translatable = 'no']"
+    translate="no"/>
+</its:rules>
+@end example
+
+@samp{xgettext} needs another file called "locating rule" to associate
+an ITS rule with an XML file.  If the above ITS file is saved as
+@file{messages.its}, the locating rule would look like:
+
+@example
+<?xml version="1.0"?>
+<locatingRules>
+  <locatingRule name="Messages" pattern="*.xml">
+    <documentRule localName="messages" target="messages.its"/>
+  </locatingRule>
+  <locatingRule name="Messages" pattern="*.msg" target="messages.its"/>
+</locatingRules>
+@end example
+
+The @code{locatingRule} element must have a @code{pattern} attribute,
+which denotes either a literal file name or a wildcard pattern of the
+XML file.  The @code{locatingRule} element can have child
+@code{documentRule} element, which adds checks on the content of the XML
+file.
+
+The first rule matches any file with the @file{.xml} file extension, but
+it only applies to XML files whose root element is @samp{<messages>}.
+
+The second rule indicates that the same ITS rule file are also
+applicable to any file with the @file{.msg} file extension.  The
+optional @code{name} attribute of @code{locatingRule} allows to choose
+rules by name, typically with @code{xgettext}'s @code{-L} option.
+
+The associated ITS rule file is indicated by the @code{target} attribute
+of @code{locatingRule} or @code{documentRule}.  If it is specified in a
+@code{documentRule} element, the parent @code{locatingRule} shouldn't
+have the @code{target} attribute.
+
+Locating rule files must have the @file{.loc} file extension.  Both ITS
+rule files and locating rule files must be installed in the
+@file{$prefix/share/gettext/its} directory.  Once those files are
+properly installed, @code{xgettext} can extract translatable strings
+from the matching XML files.
+
 @c This is the template for new data formats.
 @ignore
 
diff --git a/gettext-tools/doc/xgettext.texi b/gettext-tools/doc/xgettext.texi
index 34794aa..1a1bbc7 100644
--- a/gettext-tools/doc/xgettext.texi
+++ b/gettext-tools/doc/xgettext.texi
@@ -500,6 +500,11 @@ obsolete messages.
 Write out a NeXTstep/GNUstep localized resource file in @code{.strings} syntax.
 Note that this file format doesn't support plural forms.
 
+@item --itstool
+@opindex --itstool@r{, @code{xgettext} option}
+Write out comments recognized by itstool (@uref{http://itstool.org}).
+Note that this is only effective with XML files.
+
 @item -w @var{number}
 @itemx --width=@var{number}
 @opindex -w@r{, @code{xgettext} option}
diff --git a/gettext-tools/its/Makefile.am b/gettext-tools/its/Makefile.am
new file mode 100644
index 0000000..c8c1d10
--- /dev/null
+++ b/gettext-tools/its/Makefile.am
@@ -0,0 +1,23 @@
+## Makefile for the gettext-tools/its subdirectory of GNU gettext
+## Copyright (C) 2015 Free Software Foundation, Inc.
+##
+## This program is free software: you can redistribute it and/or modify
+## it under the terms of the GNU General Public License as published by
+## the Free Software Foundation; either version 3 of the License, or
+## (at your option) any later version.
+##
+## This program is distributed in the hope that it will be useful,
+## but WITHOUT ANY WARRANTY; without even the implied warranty of
+## MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+## GNU General Public License for more details.
+##
+## You should have received a copy of the GNU General Public License
+## along with this program.  If not, see <http://www.gnu.org/licenses/>.
+
+## Process this file with automake to produce Makefile.in.
+
+AUTOMAKE_OPTIONS = 1.2 gnits
+
+pkgdatadir = $(datadir)/gettext
+itsdir = $(pkgdatadir)$(PACKAGE_SUFFIX)/its
+dist_its_DATA =
diff --git a/gettext-tools/src/Makefile.am b/gettext-tools/src/Makefile.am
index c92cabe..279e553 100644
--- a/gettext-tools/src/Makefile.am
+++ b/gettext-tools/src/Makefile.am
@@ -40,7 +40,7 @@ read-po.h read-properties.h read-stringtable.h \
 str-list.h \
 color.h write-catalog.h write-po.h write-properties.h write-stringtable.h \
 dir-list.h file-list.h po-gram-gen.h po-gram-gen2.h cldr-plural.h \
-cldr-plural-exp.h \
+cldr-plural-exp.h locating-rule.h its.h \
 msgl-charset.h msgl-equal.h msgl-iconv.h msgl-ascii.h msgl-cat.h msgl-header.h \
 msgl-english.h msgl-check.h msgl-fsearch.h msgfmt.h msgunfmt.h \
 plural-count.h plural-eval.h plural-distrib.h \
@@ -153,7 +153,7 @@ msgl-ascii.c msgl-iconv.c msgl-equal.c msgl-cat.c msgl-header.c msgl-english.c \
 msgl-check.c file-list.c msgl-charset.c po-time.c plural-exp.c plural-eval.c \
 plural-table.c quote.h sentence.h sentence.c libexpat-compat.c \
 $(FORMAT_SOURCE) \
-read-desktop.c
+read-desktop.c locating-rule.c its.c
 
 # msggrep needs pattern matching.
 LIBGREP = ../libgrep/libgrep.a
@@ -254,7 +254,7 @@ libgettextsrc_la_LDFLAGS = \
   -release @VERSION@ \
   ../gnulib-lib/libgettextlib.la $(LTLIBUNISTRING) @LTLIBINTL@ @LTLIBICONV@ @LTLIBEXPAT@ -lc -no-undefined
 
-libgettextsrc_la_CPPFLAGS = $(AM_CPPFLAGS)
+libgettextsrc_la_CPPFLAGS = $(AM_CPPFLAGS) $(INCXML)
 
 # Tell the mingw or Cygwin linker which symbols to export.
 if WOE32DLL
diff --git a/gettext-tools/src/its.c b/gettext-tools/src/its.c
new file mode 100644
index 0000000..585e984
--- /dev/null
+++ b/gettext-tools/src/its.c
@@ -0,0 +1,1812 @@
+/* Internationalization Tag Set (ITS) handling
+   Copyright (C) 2015 Free Software Foundation, Inc.
+
+   This file was written by Daiki Ueno <ueno@gnu.org>, 2015.
+
+   This program is free software: you can redistribute it and/or modify
+   it under the terms of the GNU General Public License as published by
+   the Free Software Foundation; either version 3 of the License, or
+   (at your option) any later version.
+
+   This program is distributed in the hope that it will be useful,
+   but WITHOUT ANY WARRANTY; without even the implied warranty of
+   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+   GNU General Public License for more details.
+
+   You should have received a copy of the GNU General Public License
+   along with this program.  If not, see <http://www.gnu.org/licenses/>.  */
+
+#ifdef HAVE_CONFIG_H
+#include <config.h>
+#endif
+
+/* Specification.  */
+#include "its.h"
+
+#include <assert.h>
+#include <errno.h>
+#include "error.h"
+#include "gettext.h"
+#include "hash.h"
+#include <stdint.h>
+#include <libxml/tree.h>
+#include <libxml/parser.h>
+#include <libxml/xmlwriter.h>
+#include <libxml/xpath.h>
+#include <libxml/xpathInternals.h>
+#include <stdlib.h>
+#include "trim.h"
+#include "xalloc.h"
+#include "xvasprintf.h"
+
+#define _(str) gettext (str)
+
+/* The Internationalization Tag Set (ITS) 2.0 standard is available at:
+   http://www.w3.org/TR/its20/
+
+   This implementation supports only a few data categories, useful for
+   gettext-based projects.  Other data categories can be added by
+   extending the its_rule_class_ty class and registering it in
+   init_classes().
+
+   The message extraction is performed in three steps.  In the first
+   step, its_rule_list_apply() assigns values to nodes in an XML
+   document.  In the second step, its_rule_list_extract_nodes() marks
+   translatable nodes.  In the final step,
+   its_rule_list_extract_text() extracts text contents from the marked
+   nodes.
+
+   The values assigned to a node are represented as an array of
+   key-value pairs, where both keys and values are string.  The array
+   is stored in node->_private.  To retrieve the values for a node,
+   use its_rule_list_eval().  */
+
+#define ITS_NS "http://www.w3.org/2005/11/its"
+#define XML_NS "http://www.w3.org/XML/1998/namespace"
+#define GT_NS "https://www.gnu.org/s/gettext/ns/its/extensions/1.0"
+
+struct its_value_ty
+{
+  char *name;
+  char *value;
+};
+
+struct its_value_list_ty
+{
+  struct its_value_ty *items;
+  size_t nitems;
+  size_t nitems_max;
+};
+
+static void
+its_value_list_append (struct its_value_list_ty *values,
+                       const char *name,
+                       const char *value)
+{
+  struct its_value_ty _value;
+
+  _value.name = xstrdup (name);
+  _value.value = xstrdup (value);
+
+  if (values->nitems == values->nitems_max)
+    {
+      values->nitems_max = 2 * values->nitems_max + 1;
+      values->items =
+        xrealloc (values->items,
+                  sizeof (struct its_value_ty) * values->nitems_max);
+    }
+  memcpy (&values->items[values->nitems++], &_value,
+          sizeof (struct its_value_ty));
+}
+
+static const char *
+its_value_list_get_value (struct its_value_list_ty *values,
+                          const char *name)
+{
+  size_t i;
+
+  for (i = 0; i < values->nitems; i++)
+    {
+      struct its_value_ty *value = &values->items[i];
+      if (strcmp (value->name, name) == 0)
+        return value->value;
+    }
+  return NULL;
+}
+
+static void
+its_value_list_set_value (struct its_value_list_ty *values,
+                          const char *name,
+                          const char *value)
+{
+  size_t i;
+
+  for (i = 0; i < values->nitems; i++)
+    {
+      struct its_value_ty *_value = &values->items[i];
+      if (strcmp (_value->name, name) == 0)
+        {
+          free (_value->value);
+          _value->value = xstrdup (value);
+          break;
+        }
+    }
+
+  if (i == values->nitems)
+    its_value_list_append (values, name, value);
+}
+
+static void
+its_value_list_merge (struct its_value_list_ty *values,
+                      struct its_value_list_ty *other)
+{
+  size_t i;
+
+  for (i = 0; i < other->nitems; i++)
+    {
+      struct its_value_ty *other_value = &other->items[i];
+      size_t j;
+
+      for (j = 0; j < values->nitems; j++)
+        {
+          struct its_value_ty *value = &values->items[j];
+
+          if (strcmp (value->name, other_value->name) == 0
+              && strcmp (value->value, other_value->value) != 0)
+            {
+              free (value->value);
+              value->value = xstrdup (other_value->value);
+              break;
+            }
+        }
+
+      if (j == values->nitems)
+        its_value_list_append (values, other_value->name, other_value->value);
+    }
+}
+
+static void
+its_value_list_destroy (struct its_value_list_ty *values)
+{
+  size_t i;
+
+  for (i = 0; i < values->nitems; i++)
+    {
+      free (values->items[i].name);
+      free (values->items[i].value);
+    }
+  free (values->items);
+}
+
+struct its_pool_ty
+{
+  struct its_value_list_ty *items;
+  size_t nitems;
+  size_t nitems_max;
+};
+
+static struct its_value_list_ty *
+its_pool_alloc_value_list (struct its_pool_ty *pool)
+{
+  struct its_value_list_ty *values;
+
+  if (pool->nitems == pool->nitems_max)
+    {
+      pool->nitems_max = 2 * pool->nitems_max + 1;
+      pool->items =
+        xrealloc (pool->items,
+                  sizeof (struct its_value_list_ty) * pool->nitems_max);
+    }
+
+  values = &pool->items[pool->nitems++];
+  memset (values, 0, sizeof (struct its_value_list_ty));
+  return values;
+}
+
+static const char *
+its_pool_get_value_for_node (struct its_pool_ty *pool, xmlNode *node,
+                              const char *name)
+{
+  intptr_t index = (intptr_t) node->_private;
+  if (index > 0)
+    {
+      struct its_value_list_ty *values;
+
+      assert (index <= pool->nitems);
+      values = &pool->items[index - 1];
+
+      return its_value_list_get_value (values, name);
+    }
+  return NULL;
+}
+
+static void
+its_pool_destroy (struct its_pool_ty *pool)
+{
+  size_t i;
+
+  for (i = 0; i < pool->nitems; i++)
+    its_value_list_destroy (&pool->items[i]);
+  free (pool->items);
+}
+
+struct its_rule_list_ty
+{
+  struct its_rule_ty **items;
+  size_t nitems;
+  size_t nitems_max;
+
+  struct its_pool_ty pool;
+};
+
+struct its_node_list_ty
+{
+  xmlNode **items;
+  size_t nitems;
+  size_t nitems_max;
+};
+
+static void
+its_node_list_append (struct its_node_list_ty *nodes,
+                      xmlNode *node)
+{
+  if (nodes->nitems == nodes->nitems_max)
+    {
+      nodes->nitems_max = 2 * nodes->nitems_max + 1;
+      nodes->items =
+        xrealloc (nodes->items, sizeof (xmlNode *) * nodes->nitems_max);
+    }
+  nodes->items[nodes->nitems++] = node;
+}
+
+/* Base class representing an ITS rule in global definition.  */
+struct its_rule_class_ty
+{
+  /* How many bytes to malloc for an instance of this class.  */
+  size_t size;
+
+  /* What to do immediately after the instance is malloc()ed.  */
+  void (*constructor) (struct its_rule_ty *pop, xmlNode *node);
+
+  /* What to do immediately before the instance is free()ed.  */
+  void (*destructor) (struct its_rule_ty *pop);
+
+  /* How to apply the rule to all elements in DOC.  */
+  void (* apply) (struct its_rule_ty *pop, struct its_pool_ty *pool,
+                  xmlDoc *doc);
+
+  /* How to evaluate the value of NODE according to the rule.  */
+  struct its_value_list_ty *(* eval) (struct its_rule_ty *pop,
+                                      struct its_pool_ty *pool, xmlNode *node);
+};
+
+#define ITS_RULE_TY                             \
+  struct its_rule_class_ty *methods;            \
+  char *selector;                               \
+  struct its_value_list_ty values;              \
+  xmlNs **namespaces;
+
+struct its_rule_ty
+{
+  ITS_RULE_TY
+};
+
+static hash_table classes;
+
+static void
+its_rule_destructor (struct its_rule_ty *pop)
+{
+  free (pop->selector);
+  its_value_list_destroy (&pop->values);
+  if (pop->namespaces)
+    {
+      size_t i;
+      for (i = 0; pop->namespaces[i] != NULL; i++)
+        xmlFreeNs (pop->namespaces[i]);
+      free (pop->namespaces);
+    }
+}
+
+static void
+its_rule_apply (struct its_rule_ty *rule, struct its_pool_ty *pool, xmlDoc *doc)
+{
+  xmlXPathContext *context;
+  xmlXPathObject *object;
+  size_t i;
+
+  if (!rule->selector)
+    {
+      error (0, 0, _("selector is not specified"));
+      return;
+    }
+
+  context = xmlXPathNewContext (doc);
+  if (!context)
+    {
+      error (0, 0, _("cannot create XPath context"));
+      return;
+    }
+
+  if (rule->namespaces)
+    {
+      size_t i;
+      for (i = 0; rule->namespaces[i] != NULL; i++)
+        {
+          xmlNs *ns = rule->namespaces[i];
+          xmlXPathRegisterNs (context, ns->prefix, ns->href);
+        }
+    }
+
+  object = xmlXPathEval (BAD_CAST rule->selector, context);
+  if (!object)
+    {
+      xmlXPathFreeContext (context);
+      error (0, 0, _("cannot evaluate XPath expression: %s"), rule->selector);
+      return;
+    }
+
+  if (object->nodesetval)
+    {
+      xmlNodeSet *nodes = object->nodesetval;
+      for (i = 0; i < nodes->nodeNr; i++)
+        {
+          xmlNode *node = nodes->nodeTab[i];
+          struct its_value_list_ty *values;
+
+          /* We can't store VALUES in NODE, since the address can
+             change when realloc()ed.  */
+          intptr_t index = (intptr_t) node->_private;
+
+          assert (index <= pool->nitems);
+          if (index > 0)
+            values = &pool->items[index - 1];
+          else
+            {
+              values = its_pool_alloc_value_list (pool);
+              node->_private = (void *) pool->nitems;
+            }
+
+          its_value_list_merge (values, &rule->values);
+        }
+    }
+
+  xmlXPathFreeObject (object);
+  xmlXPathFreeContext (context);
+}
+
+static char *
+_its_get_attribute (xmlNode *node, const char *attr, const char *namespace)
+{
+  xmlChar *value;
+  char *result;
+
+  value = xmlGetNsProp (node, BAD_CAST attr, BAD_CAST namespace);
+
+  result = xstrdup ((const char *) value);
+  xmlFree (value);
+
+  return result;
+}
+
+static char *
+normalize_whitespace (const char *text, enum its_whitespace_type_ty whitespace)
+{
+  switch (whitespace)
+    {
+    case ITS_WHITESPACE_PRESERVE:
+      return xstrdup (text);
+
+    case ITS_WHITESPACE_TRIM:
+      return trim (text);
+
+    default:
+      /* Normalize whitespaces within the text, but not at the beginning
+         nor the end of the text.  */
+      {
+        char *result, *p, *end;
+
+        result = xstrdup (text);
+        end = result + strlen (result);
+        for (p = result; *p != '\0';)
+          {
+            size_t len = strspn (p, " \t\n");
+            if (len > 0)
+              {
+                *p = ' ';
+                memmove (p + 1, p + len, end - (p + len));
+                end -= len - 1;
+                *end = '\0';
+                p++;
+              }
+            p += strcspn (p, " \t\n");
+          }
+        return result;
+      }
+    }
+}
+
+static char *
+_its_encode_special_chars (const char *content, bool is_attribute)
+{
+  const char *str;
+  size_t amount = 0;
+  char *result, *p;
+
+  for (str = content; *str != '\0'; str++)
+    {
+      switch (*str)
+        {
+        case '&':
+          amount += sizeof ("&amp;");
+          break;
+        case '<':
+          amount += sizeof ("&lt;");
+          break;
+        case '>':
+          amount += sizeof ("&gt;");
+          break;
+        case '"':
+          if (is_attribute)
+            amount += sizeof ("&quot;");
+          else
+            amount += 1;
+          break;
+        default:
+          amount += 1;
+          break;
+        }
+    }
+
+  result = XNMALLOC (amount + 1, char);
+  *result = '\0';
+  p = result;
+  for (str = content; *str != '\0'; str++)
+    {
+      switch (*str)
+        {
+        case '&':
+          p = stpcpy (p, "&amp;");
+          break;
+        case '<':
+          p = stpcpy (p, "&lt;");
+          break;
+        case '>':
+          p = stpcpy (p, "&gt;");
+          break;
+        case '"':
+          if (is_attribute)
+            p = stpcpy (p, "&quot;");
+          else
+            *p++ = '"';
+          break;
+        default:
+          *p++ = *str;
+          break;
+        }
+    }
+  *p = '\0';
+  return result;
+}
+
+static char *
+_its_collect_text_content (xmlNode *node,
+                           enum its_whitespace_type_ty whitespace,
+                           bool no_escape)
+{
+  char *buffer = NULL;
+  size_t bufmax = 0;
+  size_t bufpos = 0;
+  xmlNode *n;
+
+  for (n = node->children; n; n = n->next)
+    {
+      char *content = NULL;
+
+      switch (n->type)
+        {
+        case XML_TEXT_NODE:
+        case XML_CDATA_SECTION_NODE:
+          {
+            xmlChar *xcontent = xmlNodeGetContent (n);
+            char *econtent;
+            const char *ccontent;
+
+            /* We can't expect xmlTextWriterWriteString() encode
+               special characters as we write text outside of the
+               element.  */
+            if (no_escape)
+              econtent = xstrdup ((const char *) xcontent);
+            else
+              econtent =
+                _its_encode_special_chars ((const char *) xcontent,
+                                           node->type == XML_ATTRIBUTE_NODE);
+            xmlFree (xcontent);
+
+            /* Skip whitespaces at the beginning of the text, if this
+               is the first node.  */
+            ccontent = econtent;
+            if (whitespace == ITS_WHITESPACE_NORMALIZE && !n->prev)
+              ccontent = ccontent + strspn (ccontent, " \t\n");
+            content =
+              normalize_whitespace (ccontent, whitespace);
+            free (econtent);
+
+            /* Skip whitespaces at the end of the text, if this
+               is the last node.  */
+            if (whitespace == ITS_WHITESPACE_NORMALIZE && !n->next)
+              {
+                char *p = content + strlen (content);
+                for (; p > content; p--)
+                  {
+                    int c = *(p - 1);
+                    if (!(c == ' ' || c == '\t' || c == '\n'))
+                      {
+                        *p = '\0';
+                        break;
+                      }
+                  }
+              }
+          }
+          break;
+
+        case XML_ELEMENT_NODE:
+          {
+            xmlOutputBuffer *buffer = xmlAllocOutputBuffer (NULL);
+            xmlTextWriter *writer = xmlNewTextWriter (buffer);
+            char *p = _its_collect_text_content (n, whitespace,
+                                                 no_escape);
+            const char *ccontent;
+
+            xmlTextWriterStartElement (writer, BAD_CAST n->name);
+            if (n->properties)
+              {
+                xmlAttr *attr = n->properties;
+                for (; attr; attr = attr->next)
+                  {
+                    xmlChar *prop = xmlGetProp (n, attr->name);
+                    xmlTextWriterWriteAttribute (writer,
+                                                 attr->name,
+                                                 prop);
+                    xmlFree (prop);
+                  }
+              }
+            if (*p != '\0')
+              xmlTextWriterWriteRaw (writer, BAD_CAST p);
+            xmlTextWriterEndElement (writer);
+            ccontent = (const char *) xmlOutputBufferGetContent (buffer);
+            content = normalize_whitespace (ccontent, whitespace);
+            xmlFreeTextWriter (writer);
+            free (p);
+          }
+          break;
+
+        case XML_ENTITY_REF_NODE:
+          content = xasprintf ("&%s;", (const char *) n->name);
+          break;
+
+        default:
+          break;
+        }
+
+      if (content != NULL)
+        {
+          size_t length = strlen (content);
+
+          if (bufpos + length + 1 >= bufmax)
+            {
+              bufmax = 2 * bufmax + length + 1;
+              buffer = xrealloc (buffer, bufmax);
+            }
+          strcpy (&buffer[bufpos], content);
+          bufpos += length;
+        }
+      free (content);
+    }
+
+  if (buffer == NULL)
+    buffer = xstrdup ("");
+  return buffer;
+}
+
+static void
+_its_error_missing_attribute (xmlNode *node, const char *attribute)
+{
+  error (0, 0, _("\"%s\" node does not contain \"%s\""),
+         node->name, attribute);
+}
+
+/* Implementation of Translate data category.  */
+static void
+its_translate_rule_constructor (struct its_rule_ty *pop, xmlNode *node)
+{
+  char *prop;
+
+  if (!xmlHasProp (node, BAD_CAST "selector"))
+    {
+      _its_error_missing_attribute (node, "selector");
+      return;
+    }
+
+  if (!xmlHasProp (node, BAD_CAST "translate"))
+    {
+      _its_error_missing_attribute (node, "translate");
+      return;
+    }
+
+  prop = _its_get_attribute (node, "selector", NULL);
+  if (prop)
+    pop->selector = prop;
+
+  prop = _its_get_attribute (node, "translate", NULL);
+  its_value_list_append (&pop->values, "translate", prop);
+  free (prop);
+}
+
+struct its_value_list_ty *
+its_translate_rule_eval (struct its_rule_ty *pop, struct its_pool_ty *pool,
+                         xmlNode *node)
+{
+  struct its_value_list_ty *result;
+
+  result = XCALLOC (1, struct its_value_list_ty);
+
+  switch (node->type)
+    {
+    case XML_ATTRIBUTE_NODE:
+      /* Attribute nodes don't inherit from the parent elements.  */
+      {
+        const char *value =
+          its_pool_get_value_for_node (pool, node, "translate");
+        if (value != NULL)
+          {
+            its_value_list_set_value (result, "translate", value);
+            return result;
+          }
+
+        /* The default value is translate="no".  */
+        its_value_list_append (result, "translate", "no");
+      }
+      break;
+
+    case XML_ELEMENT_NODE:
+      /* Inherit from the parent elements.  */
+      {
+        const char *value;
+
+        /* A local attribute overrides the global rule.  */
+        if (xmlHasNsProp (node, BAD_CAST "translate", BAD_CAST ITS_NS))
+          {
+            char *prop;
+
+            prop = _its_get_attribute (node, "translate", ITS_NS);
+            its_value_list_append (result, "translate", prop);
+            free (prop);
+            return result;
+          }
+
+        /* Check value for the current node.  */
+        value = its_pool_get_value_for_node (pool, node, "translate");
+        if (value != NULL)
+          {
+            its_value_list_set_value (result, "translate", value);
+            return result;
+          }
+
+        /* Recursively check value for the parent node.  */
+        if (node->parent == NULL
+            || node->parent->type != XML_ELEMENT_NODE)
+          /* The default value is translate="yes".  */
+          its_value_list_append (result, "translate", "yes");
+        else
+          {
+            struct its_value_list_ty *values;
+
+            values = its_translate_rule_eval (pop, pool, node->parent);
+            its_value_list_merge (result, values);
+            its_value_list_destroy (values);
+            free (values);
+          }
+      }
+      break;
+
+    default:
+      break;
+    }
+
+  return result;
+}
+
+static struct its_rule_class_ty its_translate_rule_class =
+  {
+    sizeof (struct its_rule_ty),
+    its_translate_rule_constructor,
+    its_rule_destructor,
+    its_rule_apply,
+    its_translate_rule_eval,
+  };
+
+/* Implementation of Localization Note data category.  */
+static void
+its_localization_note_rule_constructor (struct its_rule_ty *pop, xmlNode *node)
+{
+  char *prop;
+  xmlNode *n;
+
+  if (!xmlHasProp (node, BAD_CAST "selector"))
+    {
+      _its_error_missing_attribute (node, "selector");
+      return;
+    }
+
+  if (!xmlHasProp (node, BAD_CAST "locNoteType"))
+    {
+      _its_error_missing_attribute (node, "locNoteType");
+      return;
+    }
+
+  prop = _its_get_attribute (node, "selector", NULL);
+  if (prop)
+    pop->selector = prop;
+
+  for (n = node->children; n; n = n->next)
+    {
+      if (n->type == XML_ELEMENT_NODE
+          && xmlStrEqual (n->name, BAD_CAST "locNote")
+          && xmlStrEqual (n->ns->href, BAD_CAST ITS_NS))
+        break;
+    }
+
+  prop = _its_get_attribute (node, "locNoteType", NULL);
+  if (prop)
+    its_value_list_append (&pop->values, "locNoteType", prop);
+  free (prop);
+
+  if (n)
+    {
+      /* FIXME: Respect space attribute.  */
+      char *content = _its_collect_text_content (n, ITS_WHITESPACE_NORMALIZE,
+                                                 false);
+      its_value_list_append (&pop->values, "locNote", content);
+      free (content);
+    }
+  else if (xmlHasProp (node, BAD_CAST "locNotePointer"))
+    {
+      prop = _its_get_attribute (node, "locNotePointer", NULL);
+      its_value_list_append (&pop->values, "locNotePointer", prop);
+      free (prop);
+    }
+  /* FIXME: locNoteRef and locNoteRefPointer */
+}
+
+struct its_value_list_ty *
+its_localization_note_rule_eval (struct its_rule_ty *pop,
+                                 struct its_pool_ty *pool,
+                                 xmlNode *node)
+{
+  struct its_value_list_ty *result;
+
+  result = XCALLOC (1, struct its_value_list_ty);
+
+  switch (node->type)
+    {
+    case XML_ATTRIBUTE_NODE:
+      /* Attribute nodes don't inherit from the parent elements.  */
+      {
+        const char *value;
+
+        value = its_pool_get_value_for_node (pool, node, "locNoteType");
+        if (value != NULL)
+          its_value_list_set_value (result, "locNoteType", value);
+
+        value = its_pool_get_value_for_node (pool, node, "locNote");
+        if (value != NULL)
+          {
+            its_value_list_set_value (result, "locNote", value);
+            return result;
+          }
+
+        value = its_pool_get_value_for_node (pool, node, "locNotePointer");
+        if (value != NULL)
+          {
+            its_value_list_set_value (result, "locNotePointer", value);
+            return result;
+          }
+      }
+      break;
+
+    case XML_ELEMENT_NODE:
+      /* Inherit from the parent elements.  */
+      {
+        const char *value;
+
+        /* Local attributes overrides the global rule.  */
+        if (xmlHasNsProp (node, BAD_CAST "locNote", BAD_CAST ITS_NS)
+            || xmlHasNsProp (node, BAD_CAST "locNoteRef", BAD_CAST ITS_NS)
+            || xmlHasNsProp (node, BAD_CAST "locNoteType", BAD_CAST ITS_NS))
+          {
+            char *prop;
+
+            if (xmlHasNsProp (node, BAD_CAST "locNote", BAD_CAST ITS_NS))
+              {
+                prop = _its_get_attribute (node, "locNote", ITS_NS);
+                its_value_list_append (result, "locNote", prop);
+                free (prop);
+              }
+
+            /* FIXME: locNoteRef */
+
+            if (xmlHasNsProp (node, BAD_CAST "locNoteType", BAD_CAST ITS_NS))
+              {
+                prop = _its_get_attribute (node, "locNoteType", ITS_NS);
+                its_value_list_append (result, "locNoteType", prop);
+                free (prop);
+              }
+
+            return result;
+          }
+
+        /* Check value for the current node.  */
+        value = its_pool_get_value_for_node (pool, node, "locNoteType");
+        if (value != NULL)
+          its_value_list_set_value (result, "locNoteType", value);
+
+        value = its_pool_get_value_for_node (pool, node, "locNote");
+        if (value != NULL)
+          {
+            its_value_list_set_value (result, "locNote", value);
+            return result;
+          }
+
+        value = its_pool_get_value_for_node (pool, node, "locNotePointer");
+        if (value != NULL)
+          {
+            its_value_list_set_value (result, "locNotePointer", value);
+            return result;
+          }
+
+        /* Recursively check value for the parent node.  */
+        if (node->parent == NULL
+            || node->parent->type != XML_ELEMENT_NODE)
+          return result;
+        else
+          {
+            struct its_value_list_ty *values;
+
+            values = its_localization_note_rule_eval (pop, pool, node->parent);
+            its_value_list_merge (result, values);
+            its_value_list_destroy (values);
+            free (values);
+          }
+      }
+      break;
+
+    default:
+      break;
+    }
+
+  /* The default value is None.  */
+  return result;
+}
+
+static struct its_rule_class_ty its_localization_note_rule_class =
+  {
+    sizeof (struct its_rule_ty),
+    its_localization_note_rule_constructor,
+    its_rule_destructor,
+    its_rule_apply,
+    its_localization_note_rule_eval,
+  };
+
+/* Implementation of Element Within Text data category.  */
+static void
+its_element_within_text_rule_constructor (struct its_rule_ty *pop,
+                                          xmlNode *node)
+{
+  char *prop;
+
+  if (!xmlHasProp (node, BAD_CAST "selector"))
+    {
+      _its_error_missing_attribute (node, "selector");
+      return;
+    }
+
+  if (!xmlHasProp (node, BAD_CAST "withinText"))
+    {
+      _its_error_missing_attribute (node, "withinText");
+      return;
+    }
+
+  prop = _its_get_attribute (node, "selector", NULL);
+  if (prop)
+    pop->selector = prop;
+
+  prop = _its_get_attribute (node, "withinText", NULL);
+  its_value_list_append (&pop->values, "withinText", prop);
+  free (prop);
+}
+
+struct its_value_list_ty *
+its_element_within_text_rule_eval (struct its_rule_ty *pop,
+                                   struct its_pool_ty *pool,
+                                   xmlNode *node)
+{
+  struct its_value_list_ty *result;
+  const char *value;
+
+  result = XCALLOC (1, struct its_value_list_ty);
+
+  if (node->type != XML_ELEMENT_NODE)
+    return result;
+
+  /* A local attribute overrides the global rule.  */
+  if (xmlHasNsProp (node, BAD_CAST "withinText", BAD_CAST ITS_NS))
+    {
+      char *prop;
+
+      prop = _its_get_attribute (node, "withinText", ITS_NS);
+      its_value_list_append (result, "withinText", prop);
+      free (prop);
+      return result;
+    }
+
+  /* Doesn't inherit from the parent elements, and the default value
+     is None.  */
+  value = its_pool_get_value_for_node (pool, node, "withinText");
+  if (value != NULL)
+    its_value_list_set_value (result, "withinText", value);
+
+  return result;
+}
+
+static struct its_rule_class_ty its_element_within_text_rule_class =
+  {
+    sizeof (struct its_rule_ty),
+    its_element_within_text_rule_constructor,
+    its_rule_destructor,
+    its_rule_apply,
+    its_element_within_text_rule_eval,
+  };
+
+/* Implementation of Preserve Space data category.  */
+static void
+its_preserve_space_rule_constructor (struct its_rule_ty *pop,
+                                     xmlNode *node)
+{
+  char *prop;
+
+  if (!xmlHasProp (node, BAD_CAST "selector"))
+    {
+      _its_error_missing_attribute (node, "selector");
+      return;
+    }
+
+  if (!xmlHasProp (node, BAD_CAST "space"))
+    {
+      _its_error_missing_attribute (node, "space");
+      return;
+    }
+
+  prop = _its_get_attribute (node, "selector", NULL);
+  if (prop)
+    pop->selector = prop;
+
+  prop = _its_get_attribute (node, "space", NULL);
+  if (prop
+      && !(strcmp (prop, "preserve") ==0 
+           || strcmp (prop, "default") == 0
+           /* gettext extension: remove leading/trailing whitespaces only.  */
+           || (node->ns && xmlStrEqual (node->ns->href, BAD_CAST GT_NS)
+               && strcmp (prop, "trim") == 0)))
+    {
+      error (0, 0, _("invalid attribute value \"%s\" for \"%s\""),
+             prop, "space");
+      free (prop);
+      return;
+    }
+
+  its_value_list_append (&pop->values, "space", prop);
+  free (prop);
+}
+
+struct its_value_list_ty *
+its_preserve_space_rule_eval (struct its_rule_ty *pop,
+                              struct its_pool_ty *pool,
+                              xmlNode *node)
+{
+  struct its_value_list_ty *result;
+  struct its_value_list_ty *values;
+  const char *value;
+
+  result = XCALLOC (1, struct its_value_list_ty);
+
+  if (node->type != XML_ELEMENT_NODE)
+    return result;
+
+  /* A local attribute overrides the global rule.  */
+  if (xmlHasNsProp (node, BAD_CAST "space", BAD_CAST XML_NS))
+    {
+      char *prop;
+
+      prop = _its_get_attribute (node, "space", XML_NS);
+      its_value_list_append (result, "space", prop);
+      free (prop);
+      return result;
+    }
+
+  /* Check value for the current node.  */
+  value = its_pool_get_value_for_node (pool, node, "space");
+  if (value != NULL)
+    {
+      its_value_list_set_value (result, "space", value);
+      return result;
+    }
+
+  if (node->parent == NULL
+      || node->parent->type != XML_ELEMENT_NODE)
+    {
+      /* The default value is space="default".  */
+      its_value_list_append (result, "space", "default");
+      return result;
+    }
+
+  /* Recursively check value for the parent node.  */
+  values = its_preserve_space_rule_eval (pop, pool, node->parent);
+  its_value_list_merge (result, values);
+  its_value_list_destroy (values);
+  free (values);
+
+  return result;
+}
+
+static struct its_rule_class_ty its_preserve_space_rule_class =
+  {
+    sizeof (struct its_rule_ty),
+    its_preserve_space_rule_constructor,
+    its_rule_destructor,
+    its_rule_apply,
+    its_preserve_space_rule_eval,
+  };
+
+/* Implementation of Context data category.  */
+static void
+its_extension_context_rule_constructor (struct its_rule_ty *pop, xmlNode *node)
+{
+  char *prop;
+
+  if (!xmlHasProp (node, BAD_CAST "selector"))
+    {
+      _its_error_missing_attribute (node, "selector");
+      return;
+    }
+
+  if (!xmlHasProp (node, BAD_CAST "contextPointer"))
+    {
+      _its_error_missing_attribute (node, "contextPointer");
+      return;
+    }
+
+  prop = _its_get_attribute (node, "selector", NULL);
+  if (prop)
+    pop->selector = prop;
+
+  prop = _its_get_attribute (node, "contextPointer", NULL);
+  its_value_list_append (&pop->values, "contextPointer", prop);
+  free (prop);
+
+  if (xmlHasProp (node, BAD_CAST "textPointer"))
+    {
+      prop = _its_get_attribute (node, "textPointer", NULL);
+      its_value_list_append (&pop->values, "textPointer", prop);
+      free (prop);
+    }
+}
+
+struct its_value_list_ty *
+its_extension_context_rule_eval (struct its_rule_ty *pop,
+                                 struct its_pool_ty *pool,
+                                 xmlNode *node)
+{
+  struct its_value_list_ty *result;
+  const char *value;
+
+  result = XCALLOC (1, struct its_value_list_ty);
+
+  /* Doesn't inherit from the parent elements, and the default value
+     is None.  */
+  value = its_pool_get_value_for_node (pool, node, "contextPointer");
+  if (value != NULL)
+    its_value_list_set_value (result, "contextPointer", value);
+
+  value = its_pool_get_value_for_node (pool, node, "textPointer");
+  if (value != NULL)
+    its_value_list_set_value (result, "textPointer", value);
+
+  return result;
+}
+
+static struct its_rule_class_ty its_extension_context_rule_class =
+  {
+    sizeof (struct its_rule_ty),
+    its_extension_context_rule_constructor,
+    its_rule_destructor,
+    its_rule_apply,
+    its_extension_context_rule_eval,
+  };
+
+/* Implementation of Escape Special Characters data category.  */
+static void
+its_extension_escape_rule_constructor (struct its_rule_ty *pop, xmlNode *node)
+{
+  char *prop;
+
+  if (!xmlHasProp (node, BAD_CAST "selector"))
+    {
+      _its_error_missing_attribute (node, "selector");
+      return;
+    }
+
+  if (!xmlHasProp (node, BAD_CAST "escape"))
+    {
+      _its_error_missing_attribute (node, "escape");
+      return;
+    }
+
+  prop = _its_get_attribute (node, "selector", NULL);
+  if (prop)
+    pop->selector = prop;
+
+  prop = _its_get_attribute (node, "escape", NULL);
+  its_value_list_append (&pop->values, "escape", prop);
+  free (prop);
+}
+
+struct its_value_list_ty *
+its_extension_escape_rule_eval (struct its_rule_ty *pop,
+                                struct its_pool_ty *pool,
+                                xmlNode *node)
+{
+  struct its_value_list_ty *result;
+
+  result = XCALLOC (1, struct its_value_list_ty);
+
+  switch (node->type)
+    {
+    case XML_ATTRIBUTE_NODE:
+      /* Attribute nodes don't inherit from the parent elements.  */
+      {
+        const char *value =
+          its_pool_get_value_for_node (pool, node, "escape");
+        if (value != NULL)
+          {
+            its_value_list_set_value (result, "escape", value);
+            return result;
+          }
+      }
+      break;
+
+    case XML_ELEMENT_NODE:
+      /* Inherit from the parent elements.  */
+      {
+        const char *value;
+
+        /* Check value for the current node.  */
+        value = its_pool_get_value_for_node (pool, node, "escape");
+        if (value != NULL)
+          {
+            its_value_list_set_value (result, "escape", value);
+            return result;
+          }
+
+        /* Recursively check value for the parent node.  */
+        if (node->parent != NULL
+            && node->parent->type == XML_ELEMENT_NODE)
+          {
+            struct its_value_list_ty *values;
+
+            values = its_extension_escape_rule_eval (pop, pool, node->parent);
+            its_value_list_merge (result, values);
+            its_value_list_destroy (values);
+            free (values);
+          }
+      }
+      break;
+
+    default:
+      break;
+    }
+
+  return result;
+}
+
+static struct its_rule_class_ty its_extension_escape_rule_class =
+  {
+    sizeof (struct its_rule_ty),
+    its_extension_escape_rule_constructor,
+    its_rule_destructor,
+    its_rule_apply,
+    its_extension_escape_rule_eval,
+  };
+
+static struct its_rule_ty *
+its_rule_alloc (struct its_rule_class_ty *method_table, xmlNode *node)
+{
+  struct its_rule_ty *pop;
+
+  pop = (struct its_rule_ty *) xcalloc (1, method_table->size);
+  pop->methods = method_table;
+  if (method_table->constructor)
+    method_table->constructor (pop, node);
+  return pop;
+}
+
+static struct its_rule_ty *
+its_rule_parse (xmlDoc *doc, xmlNode *node)
+{
+  const char *name = (const char *) node->name;
+  void *value;
+
+  if (hash_find_entry (&classes, name, strlen (name), &value) == 0)
+    {
+      struct its_rule_ty *result;
+      xmlNs **namespaces;
+
+      result = its_rule_alloc ((struct its_rule_class_ty *) value, node);
+      namespaces = xmlGetNsList (doc, node);
+      if (namespaces)
+        {
+          size_t i;
+          for (i = 0; namespaces[i] != NULL; i++)
+            ;
+          result->namespaces = XCALLOC (i + 1, xmlNs *);
+          for (i = 0; namespaces[i] != NULL; i++)
+            result->namespaces[i] = xmlCopyNamespace (namespaces[i]);
+        }
+      xmlFree (namespaces);
+      return result;
+    }
+
+  return NULL;
+}
+
+static void
+its_rule_destroy (struct its_rule_ty *pop)
+{
+  if (pop->methods->destructor)
+    pop->methods->destructor (pop);
+}
+
+static void
+init_classes (void)
+{
+#define ADD_RULE_CLASS(n, c) \
+  hash_insert_entry (&classes, n, strlen (n), &c);
+
+  ADD_RULE_CLASS ("translateRule", its_translate_rule_class);
+  ADD_RULE_CLASS ("locNoteRule", its_localization_note_rule_class);
+  ADD_RULE_CLASS ("withinTextRule", its_element_within_text_rule_class);
+  ADD_RULE_CLASS ("preserveSpaceRule", its_preserve_space_rule_class);
+  ADD_RULE_CLASS ("contextRule", its_extension_context_rule_class);
+  ADD_RULE_CLASS ("escapeRule", its_extension_escape_rule_class);
+
+#undef ADD_RULE_CLASS
+}
+
+struct its_rule_list_ty *
+its_rule_list_alloc (void)
+{
+  struct its_rule_list_ty *result;
+
+  if (classes.table == NULL)
+    {
+      hash_init (&classes, 10);
+      init_classes ();
+    }
+
+  result = XCALLOC (1, struct its_rule_list_ty);
+  return result;
+}
+
+void
+its_rule_list_free (struct its_rule_list_ty *rules)
+{
+  size_t i;
+
+  for (i = 0; i < rules->nitems; i++)
+    {
+      its_rule_destroy (rules->items[i]);
+      free (rules->items[i]);
+    }
+  free (rules->items);
+  its_pool_destroy (&rules->pool);
+}
+
+static bool
+its_rule_list_add_from_doc (struct its_rule_list_ty *rules,
+                            xmlDoc *doc)
+{
+  xmlNode *root, *node;
+
+  root = xmlDocGetRootElement (doc);
+  if (!(xmlStrEqual (root->name, BAD_CAST "rules")
+        && xmlStrEqual (root->ns->href, BAD_CAST ITS_NS)))
+    {
+      error (0, 0, _("the root element is not \"rules\""
+                     " under namespace %s"),
+             ITS_NS);
+      xmlFreeDoc (doc);
+      return false;
+    }
+
+  for (node = root->children; node; node = node->next)
+    {
+      struct its_rule_ty *rule;
+
+      rule = its_rule_parse (doc, node);
+      if (!rule)
+        continue;
+
+      if (rules->nitems == rules->nitems_max)
+        {
+          rules->nitems_max = 2 * rules->nitems_max + 1;
+          rules->items =
+            xrealloc (rules->items,
+                      sizeof (struct its_rule_ty *) * rules->nitems_max);
+        }
+      rules->items[rules->nitems++] = rule;
+    }
+
+  return true;
+}
+
+bool
+its_rule_list_add_from_file (struct its_rule_list_ty *rules,
+                             const char *filename)
+{
+  xmlDoc *doc;
+  bool result;
+
+  doc = xmlReadFile (filename, "utf-8",
+                     XML_PARSE_NONET
+                     | XML_PARSE_NOWARNING
+                     | XML_PARSE_NOBLANKS
+                     | XML_PARSE_NOERROR);
+  if (doc == NULL)
+    {
+      xmlError *err = xmlGetLastError ();
+      error (0, 0, _("cannot read %s: %s"), filename, err->message);
+      return false;
+    }
+
+  result = its_rule_list_add_from_doc (rules, doc);
+  xmlFreeDoc (doc);
+  return result;
+}
+
+bool
+its_rule_list_add_from_string (struct its_rule_list_ty *rules,
+                               const char *rule)
+{
+  xmlDoc *doc;
+  bool result;
+
+  doc = xmlReadMemory (rule, strlen (rule),
+                       "(internal)",
+                       NULL,
+                       XML_PARSE_NONET
+                       | XML_PARSE_NOWARNING
+                       | XML_PARSE_NOBLANKS
+                       | XML_PARSE_NOERROR);
+  if (doc == NULL)
+    {
+      xmlError *err = xmlGetLastError ();
+      error (0, 0, _("cannot read %s: %s"), "(internal)", err->message);
+      return false;
+    }
+
+  result = its_rule_list_add_from_doc (rules, doc);
+  xmlFreeDoc (doc);
+  return result;
+}
+
+static void
+its_rule_list_apply (struct its_rule_list_ty *rules, xmlDoc *doc)
+{
+  size_t i;
+
+  for (i = 0; i < rules->nitems; i++)
+    {
+      struct its_rule_ty *rule = rules->items[i];
+      rule->methods->apply (rule, &rules->pool, doc);
+    }
+}
+
+static struct its_value_list_ty *
+its_rule_list_eval (its_rule_list_ty *rules, xmlNode *node)
+{
+  struct its_value_list_ty *result;
+  size_t i;
+
+  result = XCALLOC (1, struct its_value_list_ty);
+  for (i = 0; i < rules->nitems; i++)
+    {
+      struct its_rule_ty *rule = rules->items[i];
+      struct its_value_list_ty *values;
+
+      values = rule->methods->eval (rule, &rules->pool, node);
+      its_value_list_merge (result, values);
+      its_value_list_destroy (values);
+      free (values);
+    }
+
+  return result;
+}
+
+static bool
+its_rule_list_is_translatable (its_rule_list_ty *rules,
+                               xmlNode *node,
+                               int depth)
+{
+  struct its_value_list_ty *values;
+  const char *value;
+  xmlNode *n;
+
+  if (node->type != XML_ELEMENT_NODE
+      && node->type != XML_ATTRIBUTE_NODE)
+    return false;
+
+  values = its_rule_list_eval (rules, node);
+
+  /* Check if NODE has translate="yes".  */
+  value = its_value_list_get_value (values, "translate");
+  if (!(value && strcmp (value, "yes") == 0))
+    {
+      its_value_list_destroy (values);
+      free (values);
+      return false;
+    }
+
+  /* Check if NODE has withinText="yes", if NODE is not top-level.  */
+  if (depth > 0)
+    {
+      value = its_value_list_get_value (values, "withinText");
+      if (!(value && strcmp (value, "yes") == 0))
+        {
+          its_value_list_destroy (values);
+          free (values);
+          return false;
+        }
+    }
+
+  its_value_list_destroy (values);
+  free (values);
+
+  for (n = node->children; n; n = n->next)
+    {
+      switch (n->type)
+        {
+        case XML_ELEMENT_NODE:
+          if (!its_rule_list_is_translatable (rules, n, depth + 1))
+            return false;
+          break;
+
+        case XML_TEXT_NODE:
+        case XML_ENTITY_REF_NODE:
+          break;
+
+        default:
+          return false;
+        }
+    }
+
+  return true;
+}
+
+static void
+its_rule_list_extract_nodes (its_rule_list_ty *rules,
+                             struct its_node_list_ty *nodes,
+                             xmlNode *node)
+{
+  if (node->type == XML_ELEMENT_NODE)
+    {
+      xmlNode *n;
+
+      if (node->properties)
+        {
+          xmlAttr *attr = node->properties;
+          for (; attr; attr = attr->next)
+            {
+              xmlNode *n = (xmlNode *) attr;
+              if (its_rule_list_is_translatable (rules, n, 0))
+                its_node_list_append (nodes, n);
+            }
+        }
+
+      if (its_rule_list_is_translatable (rules, node, 0))
+        its_node_list_append (nodes, node);
+      else
+        {
+          for (n = node->children; n; n = n->next)
+            its_rule_list_extract_nodes (rules, nodes, n);
+        }
+    }
+}
+
+static char *
+_its_get_content (struct its_rule_list_ty *rules, xmlNode *node,
+                  const char *pointer,
+                  enum its_whitespace_type_ty whitespace,
+                  bool no_escape)
+{
+  xmlXPathContext *context;
+  xmlXPathObject *object;
+  size_t i;
+  char *result = NULL;
+
+  context = xmlXPathNewContext (node->doc);
+  if (!context)
+    {
+      error (0, 0, _("cannot create XPath context"));
+      return NULL;
+    }
+
+  for (i = 0; i < rules->nitems; i++)
+    {
+      struct its_rule_ty *rule = rules->items[i];
+      if (rule->namespaces)
+        {
+          size_t i;
+          for (i = 0; rule->namespaces[i] != NULL; i++)
+            {
+              xmlNs *ns = rule->namespaces[i];
+              xmlXPathRegisterNs (context, ns->prefix, ns->href);
+            }
+        }
+    }
+
+  xmlXPathSetContextNode (node, context);
+  object = xmlXPathEvalExpression (BAD_CAST pointer, context);
+  if (!object)
+    {
+      xmlXPathFreeContext (context);
+      error (0, 0, _("cannot evaluate XPath location path: %s"),
+             pointer);
+      return NULL;
+    }
+
+  switch (object->type)
+    {
+    case XPATH_NODESET:
+      {
+        xmlNodeSet *nodes = object->nodesetval;
+        string_list_ty sl;
+        size_t i;
+
+        string_list_init (&sl);
+        for (i = 0; i < nodes->nodeNr; i++)
+          {
+            char *content = _its_collect_text_content (nodes->nodeTab[i],
+                                                       whitespace,
+                                                       no_escape);
+            string_list_append (&sl, content);
+            free (content);
+          }
+        result = string_list_concat (&sl);
+        string_list_destroy (&sl);
+      }
+      break;
+
+    case XPATH_STRING:
+      result = xstrdup ((const char *) object->stringval);
+      break;
+
+    default:
+      break;
+    }
+
+  xmlXPathFreeObject (object);
+  xmlXPathFreeContext (context);
+
+  return result;
+}
+
+static void
+_its_comment_append (string_list_ty *comments, const char *data)
+{
+  /* Split multiline comment into lines, and remove leading and trailing
+     whitespace.  */
+  char *copy = xstrdup (data);
+  char *p;
+  char *q;
+
+  for (p = copy; (q = strchr (p, '\n')) != NULL; p = q + 1)
+    {
+      while (p[0] == ' ' || p[0] == '\t')
+        p++;
+      while (q > p && (q[-1] == ' ' || q[-1] == '\t'))
+        q--;
+      *q = '\0';
+      string_list_append (comments, p);
+    }
+  q = p + strlen (p);
+  while (p[0] == ' ' || p[0] == '\t')
+    p++;
+  while (q > p && (q[-1] == ' ' || q[-1] == '\t'))
+    q--;
+  *q = '\0';
+  string_list_append (comments, p);
+  free (copy);
+}
+
+static void
+its_rule_list_extract_text (its_rule_list_ty *rules,
+                            xmlNode *node,
+                            const char *logical_filename,
+                            flag_context_list_table_ty *flag_table,
+                            message_list_ty *mlp,
+                            its_extract_callback_ty callback)
+{
+  if (node->type == XML_ELEMENT_NODE
+      || node->type == XML_ATTRIBUTE_NODE)
+    {
+      struct its_value_list_ty *values;
+      const char *value;
+      char *msgid = NULL, *msgctxt = NULL, *comment = NULL;
+      enum its_whitespace_type_ty whitespace;
+      bool no_escape;
+      
+      values = its_rule_list_eval (rules, node);
+
+      value = its_value_list_get_value (values, "locNote");
+      if (value)
+        comment = xstrdup (value);
+      else
+        {
+          value = its_value_list_get_value (values, "locNotePointer");
+          if (value)
+            comment = _its_get_content (rules, node, value, ITS_WHITESPACE_TRIM,
+                                        false);
+        }
+
+      if (comment != NULL && *comment != '\0')
+        {
+          string_list_ty comments;
+          char *tmp;
+
+          string_list_init (&comments);
+          _its_comment_append (&comments, comment);
+          tmp = string_list_join (&comments, "\n", '\0', false);
+          free (comment);
+          comment = tmp;
+        }
+      else
+        /* Extract comments preceding the node.  */
+        {
+          xmlNode *sibling;
+          string_list_ty comments;
+
+          string_list_init (&comments);
+          for (sibling = node->prev; sibling; sibling = sibling->prev)
+            if (sibling->type != XML_COMMENT_NODE || sibling->prev == NULL)
+              break;
+          if (sibling)
+            {
+              if (sibling->type != XML_COMMENT_NODE)
+                sibling = sibling->next;
+              for (; sibling && sibling->type == XML_COMMENT_NODE;
+                   sibling = sibling->next)
+                {
+                  xmlChar *content = xmlNodeGetContent (sibling);
+                  _its_comment_append (&comments, (const char *) content);
+                  xmlFree (content);
+                }
+              free (comment);
+              comment = string_list_join (&comments, "\n", '\0', false);
+              string_list_destroy (&comments);
+            }
+        }
+      
+      value = its_value_list_get_value (values, "space");
+      if (value && strcmp (value, "preserve") == 0)
+        whitespace = ITS_WHITESPACE_PRESERVE;
+      else if (value && strcmp (value, "trim") == 0)
+        whitespace = ITS_WHITESPACE_TRIM;
+      else
+        whitespace = ITS_WHITESPACE_NORMALIZE;
+
+      value = its_value_list_get_value (values, "escape");
+      no_escape = value != NULL && strcmp (value, "no") == 0;
+
+      value = its_value_list_get_value (values, "contextPointer");
+      if (value)
+        msgctxt = _its_get_content (rules, node, value, ITS_WHITESPACE_PRESERVE,
+                                    no_escape);
+
+      value = its_value_list_get_value (values, "textPointer");
+      if (value)
+        msgid = _its_get_content (rules, node, value, ITS_WHITESPACE_PRESERVE,
+                                  no_escape);
+      its_value_list_destroy (values);
+      free (values);
+
+      if (msgid == NULL)
+        msgid = _its_collect_text_content (node, whitespace, no_escape);
+      if (*msgid != '\0')
+        {
+          lex_pos_ty pos;
+          message_ty *message;
+          char *marker;
+
+          pos.file_name = xstrdup (logical_filename);
+          pos.line_number = xmlGetLineNo (node);
+
+          if (node->type == XML_ELEMENT_NODE)
+            {
+              assert (node->parent);
+              marker = xasprintf ("%s/%s", node->parent->name, node->name);
+            }
+          else
+            {
+              assert (node->parent && node->parent->parent);
+              marker = xasprintf ("%s/%s@%s",
+                                  node->parent->parent->name,
+                                  node->parent->name,
+                                  node->name);
+            }
+
+          if (msgctxt != NULL && *msgctxt == '\0')
+            {
+              free (msgctxt);
+              msgctxt = NULL;
+            }
+
+          message = callback (mlp, msgctxt, msgid, &pos, comment, marker,
+                              whitespace);
+          free (marker);
+        }
+      free (msgctxt);
+      free (msgid);
+      free (comment);
+    }
+}
+
+void
+its_rule_list_extract (its_rule_list_ty *rules,
+                       FILE *fp, const char *real_filename,
+                       const char *logical_filename,
+                       flag_context_list_table_ty *flag_table,
+                       msgdomain_list_ty *mdlp,
+                       its_extract_callback_ty callback)
+{
+  xmlDoc *doc;
+  struct its_node_list_ty nodes;
+  size_t i;
+
+  doc = xmlReadFd (fileno (fp), logical_filename, NULL,
+                   XML_PARSE_NONET
+                   | XML_PARSE_NOWARNING
+                   | XML_PARSE_NOBLANKS
+                   | XML_PARSE_NOERROR);
+  if (doc == NULL)
+    {
+      xmlError *err = xmlGetLastError ();
+      error (0, 0, _("cannot read %s: %s"), logical_filename, err->message);
+      return;
+    }
+
+  its_rule_list_apply (rules, doc);
+
+  memset (&nodes, 0, sizeof (struct its_node_list_ty));
+  its_rule_list_extract_nodes (rules,
+                               &nodes,
+                               xmlDocGetRootElement (doc));
+
+  for (i = 0; i < nodes.nitems; i++)
+    its_rule_list_extract_text (rules, nodes.items[i],
+                                logical_filename,
+                                flag_table,
+                                mdlp->item[0]->messages,
+                                callback);
+
+  free (nodes.items);
+  xmlFreeDoc (doc);
+}
diff --git a/gettext-tools/src/its.h b/gettext-tools/src/its.h
new file mode 100644
index 0000000..d26bbcc
--- /dev/null
+++ b/gettext-tools/src/its.h
@@ -0,0 +1,73 @@
+/* Internationalization Tag Set (ITS) handling
+   Copyright (C) 2015 Free Software Foundation, Inc.
+
+   This file was written by Daiki Ueno <ueno@gnu.org>, 2015.
+
+   This program is free software: you can redistribute it and/or modify
+   it under the terms of the GNU General Public License as published by
+   the Free Software Foundation; either version 3 of the License, or
+   (at your option) any later version.
+
+   This program is distributed in the hope that it will be useful,
+   but WITHOUT ANY WARRANTY; without even the implied warranty of
+   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+   GNU General Public License for more details.
+
+   You should have received a copy of the GNU General Public License
+   along with this program.  If not, see <http://www.gnu.org/licenses/>.  */
+
+#ifndef _ITS_H_
+#define _ITS_H_
+
+#include "message.h"
+#include "xgettext.h"
+
+#ifdef __cplusplus
+extern "C" {
+#endif
+
+enum its_whitespace_type_ty
+{
+  ITS_WHITESPACE_PRESERVE,
+  ITS_WHITESPACE_NORMALIZE,
+  ITS_WHITESPACE_TRIM
+};
+
+typedef struct its_rule_list_ty its_rule_list_ty;
+
+typedef message_ty *
+        (*its_extract_callback_ty) (message_list_ty *mlp,
+                                    const char *msgctxt,
+                                    const char *msgid,
+                                    lex_pos_ty *pos,
+                                    const char *extracted_comment,
+                                    const char *marker,
+                                    enum its_whitespace_type_ty whitespace);
+
+/* Creates a fresh its_rule_list_ty holding global ITS rules.  */
+extern its_rule_list_ty *its_rule_list_alloc (void);
+
+/* Releases memory allocated for RULES.  */
+extern void its_rule_list_free (its_rule_list_ty *rules);
+
+/* Loads global ITS rules from STRING.  */
+extern bool its_rule_list_add_from_string (struct its_rule_list_ty *rules,
+                                           const char *rule);
+
+/* Loads global ITS rules from FILENAME.  */
+extern bool its_rule_list_add_from_file (its_rule_list_ty *rules,
+                                         const char *filename);
+
+/* Extracts messages from FP, accoding to the loaded ITS rules.  */
+extern void its_rule_list_extract (its_rule_list_ty *rules,
+                                   FILE *fp, const char *real_filename,
+                                   const char *logical_filename,
+                                   flag_context_list_table_ty *flag_table,
+                                   msgdomain_list_ty *mdlp,
+                                   its_extract_callback_ty callback);
+
+#ifdef __cplusplus
+}
+#endif
+
+#endif	/* _ITS_H_ */
diff --git a/gettext-tools/src/locating-rule.c b/gettext-tools/src/locating-rule.c
new file mode 100644
index 0000000..2a1de19
--- /dev/null
+++ b/gettext-tools/src/locating-rule.c
@@ -0,0 +1,437 @@
+/* XML resource locating rules
+   Copyright (C) 2015 Free Software Foundation, Inc.
+
+   This file was written by Daiki Ueno <ueno@gnu.org>, 2015.
+
+   This program is free software: you can redistribute it and/or modify
+   it under the terms of the GNU General Public License as published by
+   the Free Software Foundation; either version 3 of the License, or
+   (at your option) any later version.
+
+   This program is distributed in the hope that it will be useful,
+   but WITHOUT ANY WARRANTY; without even the implied warranty of
+   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+   GNU General Public License for more details.
+
+   You should have received a copy of the GNU General Public License
+   along with this program.  If not, see <http://www.gnu.org/licenses/>.  */
+
+#ifdef HAVE_CONFIG_H
+# include <config.h>
+#endif
+
+/* Specification.  */
+#include "locating-rule.h"
+
+#include "basename.h"
+#include "concat-filename.h"
+#include "c-strcase.h"
+
+#if HAVE_DIRENT_H
+# include <dirent.h>
+#endif
+
+#if HAVE_DIRENT_H
+# define HAVE_DIR 1
+#else
+# define HAVE_DIR 0
+#endif
+
+#include "dir-list.h"
+#include <errno.h>
+#include "error.h"
+#include "filename.h"
+#include <fnmatch.h>
+#include "gettext.h"
+#include "hash.h"
+#include <libxml/parser.h>
+#include <libxml/uri.h>
+#include "xalloc.h"
+
+#define _(str) gettext (str)
+
+#define LOCATING_RULES_NS "https://www.gnu.org/s/gettext/ns/locating-rules/1.0"
+
+struct document_locating_rule_ty
+{
+  char *ns;
+  char *local_name;
+
+  char *target;
+};
+
+struct document_locating_rule_list_ty
+{
+  struct document_locating_rule_ty *items;
+  size_t nitems;
+  size_t nitems_max;
+};
+
+struct locating_rule_ty
+{
+  char *pattern;
+  char *name;
+
+  struct document_locating_rule_list_ty doc_rules;
+  char *target;
+};
+
+struct locating_rule_list_ty
+{
+  struct locating_rule_ty *items;
+  size_t nitems;
+  size_t nitems_max;
+};
+
+static char *
+get_attribute (xmlNode *node, const char *attr)
+{
+  xmlChar *value;
+  char *result;
+
+  value = xmlGetProp (node, BAD_CAST attr);
+  result = xstrdup ((const char *) value);
+  xmlFree (value);
+
+  return result;
+}
+
+static const char *
+document_locating_rule_match (struct document_locating_rule_ty *rule,
+                              xmlDoc *doc)
+{
+  xmlNode *root;
+
+  root = xmlDocGetRootElement (doc);
+  if (rule->ns != NULL)
+    {
+      if (root->ns == NULL
+          || !xmlStrEqual (root->ns->href, BAD_CAST rule->ns))
+        return NULL;
+    }
+
+  if (rule->local_name != NULL)
+    {
+      if (!xmlStrEqual (root->name,
+                        BAD_CAST rule->local_name))
+        return NULL;
+    }
+
+  return rule->target;
+}
+
+static const char *
+locating_rule_match (struct locating_rule_ty *rule,
+                     const char *filename,
+                     const char *name)
+{
+  if (name != NULL)
+    {
+      if (rule->name == NULL || c_strcasecmp (name, rule->name) != 0)
+        return NULL;
+    }
+  else
+    {
+      const char *base;
+      char *reduced;
+      int err;
+
+      base = strrchr (filename, '/');
+      if (!base)
+        base = filename;
+
+      reduced = xstrdup (base);
+      /* Remove a trailing ".in" - it's a generic suffix.  */
+      while (strlen (reduced) >= 3
+             && memcmp (reduced + strlen (reduced) - 3, ".in", 3) == 0)
+        reduced[strlen (reduced) - 3] = '\0';
+
+      err = fnmatch (rule->pattern, basename (reduced), FNM_PATHNAME);
+      free (reduced);
+      if (err != 0)
+        return NULL;
+    }
+
+  /* Check documentRules.  */
+  if (rule->doc_rules.nitems > 0)
+    {
+      const char *target;
+      xmlDoc *doc;
+      size_t i;
+
+      doc = xmlReadFile (filename, NULL,
+                         XML_PARSE_NONET
+                         | XML_PARSE_NOWARNING
+                         | XML_PARSE_NOBLANKS
+                         | XML_PARSE_NOERROR);
+      if (doc == NULL)
+        {
+          xmlError *err = xmlGetLastError ();
+          error (0, 0, _("cannot read %s: %s"), filename, err->message);
+          return NULL;
+        }
+
+      for (i = 0, target = NULL; i < rule->doc_rules.nitems; i++)
+        {
+          target =
+            document_locating_rule_match (&rule->doc_rules.items[i], doc);
+          if (target)
+            break;
+        }
+      xmlFreeDoc (doc);
+      if (target != NULL)
+        return target;
+    }
+
+  if (rule->target != NULL)
+    return rule->target;
+
+  return NULL;
+}
+
+const char *
+locating_rule_list_locate (struct locating_rule_list_ty *rules,
+                           const char *filename,
+                           const char *name)
+{
+  const char *target = NULL;
+  size_t i;
+
+  for (i = 0; i < rules->nitems; i++)
+    {
+      if (IS_ABSOLUTE_PATH (filename))
+        {
+          target = locating_rule_match (&rules->items[i], filename, name);
+          if (target != NULL)
+            return target;
+        }
+      else
+        {
+          int j;
+
+          for (j = 0; ; ++j)
+            {
+              const char *dir = dir_list_nth (j);
+              char *new_filename;
+
+              if (dir == NULL)
+                break;
+              
+              new_filename = xconcatenated_filename (dir, filename, NULL);
+              target = locating_rule_match (&rules->items[i], new_filename,
+                                            name);
+              free (new_filename);
+              if (target != NULL)
+                return target;
+            }
+        }
+    }
+
+  return NULL;
+}
+
+static void
+missing_attribute (xmlNode *node, const char *attribute)
+{
+  error (0, 0, _("\"%s\" node does not have \"%s\""), node->name, attribute);
+}
+
+static void
+document_locating_rule_destroy (struct document_locating_rule_ty *rule)
+{
+  free (rule->ns);
+  free (rule->local_name);
+  free (rule->target);
+}
+
+static void
+document_locating_rule_list_add (struct document_locating_rule_list_ty *rules,
+                                 xmlNode *node)
+{
+  struct document_locating_rule_ty rule;
+
+  if (!xmlHasProp (node, BAD_CAST "target"))
+    {
+      missing_attribute (node, "target");
+      return;
+    }
+
+  memset (&rule, 0, sizeof (struct document_locating_rule_ty));
+
+  if (xmlHasProp (node, BAD_CAST "ns"))
+    rule.ns = get_attribute (node, "ns");
+  if (xmlHasProp (node, BAD_CAST "localName"))
+    rule.local_name = get_attribute (node, "localName");
+  rule.target = get_attribute (node, "target");
+
+  if (rules->nitems == rules->nitems_max)
+    {
+      rules->nitems_max = 2 * rules->nitems_max + 1;
+      rules->items =
+        xrealloc (rules->items,
+                  sizeof (struct document_locating_rule_ty)
+                  * rules->nitems_max);
+    }
+  memcpy (&rules->items[rules->nitems++], &rule,
+          sizeof (struct document_locating_rule_ty));
+}
+
+static void
+locating_rule_destroy (struct locating_rule_ty *rule)
+{
+  size_t i;
+
+  for (i = 0; i < rule->doc_rules.nitems; i++)
+    document_locating_rule_destroy (&rule->doc_rules.items[i]);
+  free (rule->doc_rules.items);
+
+  free (rule->name);
+  free (rule->pattern);
+  free (rule->target);
+}
+
+static bool
+locating_rule_list_add_from_file (struct locating_rule_list_ty *rules,
+                                  const char *rule_file_name)
+{
+  xmlDoc *doc;
+  xmlNode *root, *node;
+
+  doc = xmlReadFile (rule_file_name, "utf-8",
+                     XML_PARSE_NONET
+                     | XML_PARSE_NOWARNING
+                     | XML_PARSE_NOBLANKS
+                     | XML_PARSE_NOERROR);
+  if (doc == NULL)
+    {
+      error (0, 0, _("cannot read XML file %s"), rule_file_name);
+      return false;
+    }
+
+  root = xmlDocGetRootElement (doc);
+  if (!(xmlStrEqual (root->name, BAD_CAST "locatingRules")
+#if 0
+        && root->ns
+        && xmlStrEqual (root->ns->href, BAD_CAST LOCATING_RULES_NS)
+#endif
+        ))
+    {
+      error (0, 0, _("the root element is not \"locatingRules\""));
+      xmlFreeDoc (doc);
+      return false;
+    }
+
+  for (node = root->children; node; node = node->next)
+    {
+      if (xmlStrEqual (node->name, BAD_CAST "locatingRule"))
+        {
+          struct locating_rule_ty rule;
+
+          if (!xmlHasProp (node, BAD_CAST "pattern"))
+            {
+              missing_attribute (node, "pattern");
+              xmlFreeDoc (doc);
+              continue;
+            }
+
+          memset (&rule, 0, sizeof (struct locating_rule_ty));
+          rule.pattern = get_attribute (node, "pattern");
+          if (xmlHasProp (node, BAD_CAST "name"))
+            rule.name = get_attribute (node, "name");
+          if (xmlHasProp (node, BAD_CAST "target"))
+            rule.target = get_attribute (node, "target");
+          else
+            {
+              xmlNode *n;
+
+              for (n = node->children; n; n = n->next)
+                {
+                  if (xmlStrEqual (n->name, BAD_CAST "documentRule"))
+                    document_locating_rule_list_add (&rule.doc_rules, n);
+                }
+            }
+          if (rules->nitems == rules->nitems_max)
+            {
+              rules->nitems_max = 2 * rules->nitems_max + 1;
+              rules->items =
+                xrealloc (rules->items,
+                          sizeof (struct locating_rule_ty) * rules->nitems_max);
+            }
+          memcpy (&rules->items[rules->nitems++], &rule,
+                  sizeof (struct locating_rule_ty));
+        }
+    }
+
+  xmlFreeDoc (doc);
+  return true;
+}
+
+bool
+locating_rule_list_add_from_directory (struct locating_rule_list_ty *rules,
+                                       const char *directory)
+{
+#if HAVE_DIR
+  DIR *dirp;
+
+  dirp = opendir (directory);
+  if (dirp == NULL)
+    return false;
+
+  for (;;)
+    {
+      struct dirent *dp;
+
+      errno = 0;
+      dp = readdir (dirp);
+      if (dp != NULL)
+        {
+          const char *name = dp->d_name;
+          size_t namlen = strlen (name);
+
+          if (namlen > 4 && memcmp (name + namlen - 4, ".loc", 4) == 0)
+            {
+              char *locator_file_name =
+                xconcatenated_filename (directory, name, NULL);
+              locating_rule_list_add_from_file (rules, locator_file_name);
+              free (locator_file_name);
+            }
+        }
+      else if (errno != 0)
+        return false;
+      else
+        break;
+    }
+  if (closedir (dirp))
+    return false;
+
+#endif
+  return true;
+}
+
+struct locating_rule_list_ty *
+locating_rule_list_alloc (void)
+{
+  struct locating_rule_list_ty *result;
+
+  xmlCheckVersion (LIBXML_VERSION);
+
+  result = XCALLOC (1, struct locating_rule_list_ty);
+
+  return result;
+}
+
+void
+locating_rule_list_destroy (struct locating_rule_list_ty *rules)
+{
+  while (rules->nitems-- > 0)
+    locating_rule_destroy (&rules->items[rules->nitems]);
+  free (rules->items);
+}
+
+void
+locating_rule_list_free (struct locating_rule_list_ty *rules)
+{
+  if (rules != NULL)
+    locating_rule_list_destroy (rules);
+  free (rules);
+}
diff --git a/gettext-tools/src/locating-rule.h b/gettext-tools/src/locating-rule.h
new file mode 100644
index 0000000..f1214bc
--- /dev/null
+++ b/gettext-tools/src/locating-rule.h
@@ -0,0 +1,50 @@
+/* XML resource locating rules
+   Copyright (C) 2015 Free Software Foundation, Inc.
+
+   This file was written by Daiki Ueno <ueno@gnu.org>, 2015.
+
+   This program is free software: you can redistribute it and/or modify
+   it under the terms of the GNU General Public License as published by
+   the Free Software Foundation; either version 3 of the License, or
+   (at your option) any later version.
+
+   This program is distributed in the hope that it will be useful,
+   but WITHOUT ANY WARRANTY; without even the implied warranty of
+   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+   GNU General Public License for more details.
+
+   You should have received a copy of the GNU General Public License
+   along with this program.  If not, see <http://www.gnu.org/licenses/>.  */
+
+#ifndef _LOCATING_RULE_H
+#define _LOCATING_RULE_H
+
+#include <stdbool.h>
+
+#ifdef __cplusplus
+extern "C" {
+#endif
+
+typedef struct locating_rule_list_ty locating_rule_list_ty;
+
+/* Creates a fresh locating_rule_list_ty.  */
+extern struct locating_rule_list_ty *locating_rule_list_alloc (void);
+
+extern bool
+       locating_rule_list_add_from_directory (locating_rule_list_ty *rules,
+                                         const char *directory);
+
+/* Determines the location of resource associated with FILENAME,
+   accoding to the loaded locating rules.  */
+extern const char *locating_rule_list_locate (locating_rule_list_ty *rules,
+                                              const char *filename,
+                                              const char *name);
+
+/* Releases memory allocated for RULES.  */
+extern void locating_rule_list_free (locating_rule_list_ty *rules);
+
+#ifdef __cplusplus
+}
+#endif
+
+#endif  /* _LOCATING_RULE_H */
diff --git a/gettext-tools/src/xgettext.c b/gettext-tools/src/xgettext.c
index 89d4d45..bb63a26 100644
--- a/gettext-tools/src/xgettext.c
+++ b/gettext-tools/src/xgettext.c
@@ -29,6 +29,7 @@
 #include <stdlib.h>
 #include <stdbool.h>
 #include <string.h>
+#include <sys/stat.h>
 #include <locale.h>
 #include <limits.h>
 
@@ -71,6 +72,8 @@
 #include "propername.h"
 #include "sentence.h"
 #include "unistr.h"
+#include "its.h"
+#include "locating-rule.h"
 #include "gettext.h"
 
 /* A convenience macro.  I don't like writing gettext() every time.  */
@@ -105,6 +108,10 @@
 #include "x-desktop.h"
 
 
+#define SIZEOF(a) (sizeof(a) / sizeof(a[0]))
+#define ENDOF(a) ((a) + SIZEOF(a))
+
+
 /* If nonzero add all comments immediately preceding one of the keywords. */
 static bool add_all_comments = false;
 
@@ -205,6 +212,17 @@ const char *xgettext_current_source_encoding;
 iconv_t xgettext_current_source_iconv;
 #endif
 
+static locating_rule_list_ty *its_locating_rules;
+
+#define ITS_ROOT_UNTRANSLATABLE \
+  "<its:rules xmlns:its=\"http://www.w3.org/2005/11/its\"" \
+  "           version=\"2.0\">" \
+  "  <its:translateRule selector=\"/*\" translate=\"no\"/>" \
+  "</its:rules>"
+
+/* If nonzero add comments used by itstool. */
+static bool add_itstool_comments = false;
+
 /* Long options.  */
 static const struct option long_options[] =
 {
@@ -228,6 +246,7 @@ static const struct option long_options[] =
   { "from-code", required_argument, NULL, CHAR_MAX + 3 },
   { "help", no_argument, NULL, 'h' },
   { "indent", no_argument, NULL, 'i' },
+  { "itstool", no_argument, NULL, CHAR_MAX + 19 },
   { "join-existing", no_argument, NULL, 'j' },
   { "kde", no_argument, NULL, CHAR_MAX + 10 },
   { "keyword", optional_argument, NULL, 'k' },
@@ -288,6 +307,9 @@ static void usage (int status)
 static void read_exclusion_file (char *file_name);
 static void extract_from_file (const char *file_name, extractor_ty extractor,
                                msgdomain_list_ty *mdlp);
+static void extract_from_xml_file (const char *file_name,
+                                   its_rule_list_ty *rules,
+                                   msgdomain_list_ty *mdlp);
 static message_ty *construct_header (void);
 static void finalize_header (msgdomain_list_ty *mdlp);
 static extractor_ty language_to_extractor (const char *name);
@@ -306,6 +328,7 @@ main (int argc, char *argv[])
   bool some_additional_keywords = false;
   bool sort_by_msgid = false;
   bool sort_by_filepos = false;
+  char *its_dirs[2] = { NULL, NULL };
   const char *file_name;
   const char *files_from = NULL;
   string_list_ty *file_list;
@@ -378,7 +401,6 @@ main (int argc, char *argv[])
         x_tcl_extract_all ();
         x_perl_extract_all ();
         x_php_extract_all ();
-        x_glade_extract_all ();
         x_lua_extract_all ();
         x_javascript_extract_all ();
         x_vala_extract_all ();
@@ -458,7 +480,6 @@ main (int argc, char *argv[])
         x_tcl_keyword (optarg);
         x_perl_keyword (optarg);
         x_php_keyword (optarg);
-        x_glade_keyword (optarg);
         x_lua_keyword (optarg);
         x_javascript_keyword (optarg);
         x_vala_keyword (optarg);
@@ -634,6 +655,10 @@ main (int argc, char *argv[])
           error (EXIT_FAILURE, 0, _("sentence end type '%s' unknown"), optarg);
         break;
 
+      case CHAR_MAX + 19: /* --itstool */
+        add_itstool_comments = true;
+        break;
+
       default:
         usage (EXIT_FAILURE);
         /* NOTREACHED */
@@ -694,6 +719,30 @@ xgettext cannot work without keywords to look for"));
       usage (EXIT_FAILURE);
     }
 
+  {
+    const char *gettextdatadir;
+    char *versioned_gettextdatadir;
+
+    /* Make it possible to override the locator file location.  This
+       is necessary for running the testsuite before "make
+       install".  */
+    gettextdatadir = getenv ("GETTEXTDATADIR");
+    if (gettextdatadir == NULL || gettextdatadir[0] == '\0')
+      gettextdatadir = relocate (GETTEXTDATADIR);
+
+    its_dirs[0] = xconcatenated_filename (gettextdatadir, "its", NULL);
+
+    versioned_gettextdatadir =
+      xasprintf ("%s%s", relocate (GETTEXTDATADIR), PACKAGE_SUFFIX);
+    its_dirs[1] = xconcatenated_filename (versioned_gettextdatadir, "its",
+                                          NULL);
+    free (versioned_gettextdatadir);
+
+    its_locating_rules = locating_rule_list_alloc ();
+    for (i = 0; i < SIZEOF (its_dirs); i++)
+      locating_rule_list_add_from_directory (its_locating_rules, its_dirs[i]);
+  }
+
   /* Determine extractor from language.  */
   if (language != NULL)
     extractor = language_to_extractor (language);
@@ -792,6 +841,7 @@ This version was built without iconv()."),
     {
       const char *filename;
       extractor_ty this_file_extractor;
+      its_rule_list_ty *its_rules = NULL;
 
       filename = file_list->item[i];
 
@@ -799,11 +849,9 @@ This version was built without iconv()."),
         this_file_extractor = extractor;
       else
         {
+          const char *language_from_extension = NULL;
           const char *base;
           char *reduced;
-          const char *extension;
-          const char *language;
-          const char *p;
 
           base = strrchr (filename, '/');
           if (!base)
@@ -815,39 +863,103 @@ This version was built without iconv()."),
                  && memcmp (reduced + strlen (reduced) - 3, ".in", 3) == 0)
             reduced[strlen (reduced) - 3] = '\0';
 
-          /* Work out what the file extension is.  */
-          language = NULL;
-          p = reduced + strlen (reduced);
-          for (; p > reduced && language == NULL; p--)
+          /* If no language is specified with -L, deduce it the extension.  */
+          if (language == NULL)
             {
-              if (*p == '.')
+              const char *p;
+
+              /* Work out what the file extension is.  */
+              p = reduced + strlen (reduced);
+              for (; p > reduced && language_from_extension == NULL; p--)
                 {
-                  extension = p + 1;
+                  if (*p == '.')
+                    {
+                      const char *extension = p + 1;
 
-                  /* Derive the language from the extension, and the extractor
-                     function from the language.  */
-                  language = extension_to_language (extension);
+                      /* Derive the language from the extension, and
+                         the extractor function from the language.  */
+                      language_from_extension =
+                        extension_to_language (extension);
+                    }
                 }
             }
 
-          if (language == NULL)
+          /* If language is not determined from the file name
+             extension, check ITS locating rules.  */
+          if (language_from_extension == NULL
+              && strcmp (filename, "-") != 0)
             {
-              extension = strrchr (reduced, '.');
-              if (extension == NULL)
-                extension = "";
-              else
-                extension++;
-              error (0, 0, _("\
+              const char *its_basename;
+
+              its_basename = locating_rule_list_locate (its_locating_rules,
+                                                          filename,
+                                                          language);
+
+              if (its_basename != NULL)
+                {
+                  size_t j;
+
+                  its_rules = its_rule_list_alloc ();
+
+                  /* If the ITS file is identified by the name,
+                     set the root element untranslatable.  */
+                  if (language != NULL)
+                    its_rule_list_add_from_string (its_rules,
+                                                   ITS_ROOT_UNTRANSLATABLE);
+
+                  for (j = 0; j < SIZEOF (its_dirs); j++)
+                    {
+                      char *its_filename =
+                        xconcatenated_filename (its_dirs[j], its_basename,
+                                                NULL);
+                      struct stat statbuf;
+                      bool ok = false;
+
+                      if (stat (its_filename, &statbuf) == 0)
+                        ok = its_rule_list_add_from_file (its_rules,
+                                                          its_filename);
+                      free (its_filename);
+                      if (ok)
+                        break;
+                    }
+                  if (j == SIZEOF (its_dirs))
+                    {
+                      its_rule_list_free (its_rules);
+                      its_rules = NULL;
+                    }
+                }
+            }
+
+          if (its_rules == NULL)
+            {
+              if (language_from_extension == NULL)
+                {
+                  const char *extension = strrchr (reduced, '.');
+                  if (extension == NULL)
+                    extension = "";
+                  else
+                    extension++;
+                  error (0, 0, _("\
 warning: file '%s' extension '%s' is unknown; will try C"), filename, extension);
-              language = "C";
+                  language_from_extension = "C";
+                }
+
+              this_file_extractor =
+                language_to_extractor (language_from_extension);
             }
-          this_file_extractor = language_to_extractor (language);
 
           free (reduced);
         }
 
-      /* Extract the strings from the file.  */
-      extract_from_file (filename, this_file_extractor, mdlp);
+      if (its_rules != NULL)
+        {
+          /* Extract the strings from the file, using ITS.  */
+          extract_from_xml_file (filename, its_rules, mdlp);
+          its_rule_list_free (its_rules);
+        }
+      else
+        /* Extract the strings from the file.  */
+        extract_from_file (filename, this_file_extractor, mdlp);
     }
   string_list_free (file_list);
 
@@ -889,6 +1001,12 @@ warning: file '%s' extension '%s' is unknown; will try C"), filename, extension)
   /* Write the PO file.  */
   msgdomain_list_print (mdlp, file_name, output_syntax, force_po, do_debug);
 
+  if (its_locating_rules)
+    locating_rule_list_free (its_locating_rules);
+
+  for (i = 0; i < SIZEOF (its_dirs); i++)
+    free (its_dirs[i]);
+
   exit (EXIT_SUCCESS);
 }
 
@@ -1051,6 +1169,8 @@ Output details:\n"));
       printf (_("\
       --stringtable-output    write out a NeXTstep/GNUstep .strings file\n"));
       printf (_("\
+      --itstool               write out itstool comments\n"));
+      printf (_("\
   -w, --width=NUMBER          set output page width\n"));
       printf (_("\
       --no-wrap               do not break long message lines, longer than\n\
@@ -2112,6 +2232,63 @@ extract_from_file (const char *file_name, extractor_ty extractor,
   free (real_file_name);
 }
 
+static message_ty *
+xgettext_its_extract_callback (message_list_ty *mlp,
+                               const char *msgctxt,
+                               const char *msgid,
+                               lex_pos_ty *pos,
+                               const char *extracted_comment,
+                               const char *marker,
+                               enum its_whitespace_type_ty whitespace)
+{
+  message_ty *message;
+
+  message = remember_a_message (mlp,
+                                msgctxt == NULL ? NULL : xstrdup (msgctxt),
+                                xstrdup (msgid),
+                                null_context, pos,
+                                extracted_comment, NULL);
+
+  if (add_itstool_comments)
+    {
+      char *dot = xasprintf ("(itstool) path: %s", marker);
+      message_comment_dot_append (message, dot);
+      free (dot);
+
+      if (whitespace == ITS_WHITESPACE_PRESERVE)
+        message->do_wrap = no;
+    }
+
+  return message;
+}
+
+static void
+extract_from_xml_file (const char *file_name,
+                       its_rule_list_ty *rules,
+                       msgdomain_list_ty *mdlp)
+{
+  char *logical_file_name;
+  char *real_file_name;
+  FILE *fp = xgettext_open (file_name, &logical_file_name, &real_file_name);
+
+  /* Set the default for the source file encoding.  May be overridden by
+     the extractor function.  */
+  xgettext_current_source_encoding = xgettext_global_source_encoding;
+#if HAVE_ICONV
+  xgettext_current_source_iconv = xgettext_global_source_iconv;
+#endif
+
+  its_rule_list_extract (rules, fp, real_file_name, logical_file_name,
+                         NULL,
+                         mdlp,
+                         xgettext_its_extract_callback);
+
+  if (fp != stdin)
+    fclose (fp);
+  free (logical_file_name);
+  free (real_file_name);
+}
+
 
 
 /* Error message about non-ASCII character in a specific lexical context.  */
@@ -3663,10 +3840,6 @@ finalize_header (msgdomain_list_ty *mdlp)
 }
 
 
-#define SIZEOF(a) (sizeof(a) / sizeof(a[0]))
-#define ENDOF(a) ((a) + SIZEOF(a))
-
-
 static extractor_ty
 language_to_extractor (const char *name)
 {
diff --git a/gettext-tools/tests/Makefile.am b/gettext-tools/tests/Makefile.am
index a1f4a59..bb24284 100644
--- a/gettext-tools/tests/Makefile.am
+++ b/gettext-tools/tests/Makefile.am
@@ -113,6 +113,7 @@ TESTS = gettext-1 gettext-2 gettext-3 gettext-4 gettext-5 gettext-6 gettext-7 \
 	xgettext-vala-1 \
 	xgettext-gsettings-1 \
 	xgettext-desktop-1 \
+	xgettext-its-1 \
 	format-awk-1 format-awk-2 \
 	format-boost-1 format-boost-2 \
 	format-c-1 format-c-2 format-c-3 format-c-4 format-c-5 \
diff --git a/gettext-tools/tests/init-env.in b/gettext-tools/tests/init-env.in
index 1ee4775..5d5bb89 100644
--- a/gettext-tools/tests/init-env.in
+++ b/gettext-tools/tests/init-env.in
@@ -1,6 +1,10 @@
 # Variable needed by LTLIBINTL.
 top_builddir=../..
 
+# Variable needed by xgettext.
+GETTEXTDATADIR="$abs_top_srcdir"
+export GETTEXTDATADIR
+
 OBJEXT="@OBJEXT@"
 EXEEXT="@EXEEXT@"
 CC="@CC@"
diff --git a/gettext-tools/tests/xgettext-its-1 b/gettext-tools/tests/xgettext-its-1
new file mode 100755
index 0000000..26a149c
--- /dev/null
+++ b/gettext-tools/tests/xgettext-its-1
@@ -0,0 +1,255 @@
+#!/bin/sh
+. "${srcdir=.}/init.sh"; path_prepend_ . ../src
+
+# Test of ITS support.
+
+: ${XGETTEXT=xgettext}
+
+GETTEXTDATADIR=.
+export GETTEXTDATADIR
+
+cat <<\EOF > empty.xml
+<?xml version="1.0"?>
+<empty></empty>
+EOF
+
+${XGETTEXT} --itstool -o empty.pot empty.xml 2>empty.err || { cat empty.err; exit 1; }
+
+test -d its || mkdir its
+
+cat <<\EOF > its/empty-1.loc
+<?xml version="1.0"?>
+<locatingRules/>
+EOF
+
+${XGETTEXT} --itstool -o empty.pot empty.xml 2>empty.err || { cat empty.err; exit 1; }
+
+cat <<\EOF > its/empty-2.loc
+<?xml version="1.0"?>
+<locatingRules>
+  <locatingRule pattern="*.xml">
+    <documentRule prefix="" localName="empty" target="empty.its"/>
+  </locatingRule>
+</locatingRules>
+EOF
+
+${XGETTEXT} --itstool -o empty.pot empty.xml 2>empty.err || { cat empty.err; exit 1; }
+
+cat <<\EOF > its/empty.its
+<?xml version="1.0"?>
+<its:rules xmlns:its="http://www.w3.org/2005/11/its" version="1.0">
+</its:rules>
+EOF
+
+${XGETTEXT} --itstool -o empty.pot empty.xml 2>empty.err || { cat empty.err; exit 1; }
+
+cat <<\EOF > its/messages.loc
+<?xml version="1.0"?>
+<locatingRules>
+  <locatingRule pattern="*.xml">
+    <documentRule localName="messages" target="messages.its"/>
+  </locatingRule>
+  <locatingRule pattern="*.msg">
+    <documentRule localName="messages" target="messages.its"/>
+  </locatingRule>
+</locatingRules>
+EOF
+
+cat <<\EOF > its/messages.its
+<?xml version="1.0"?>
+<its:rules xmlns:its="http://www.w3.org/2005/11/its"
+           xmlns:gt="https://www.gnu.org/s/gettext/ns/its/extensions/1.0"
+           xmlns:msg="http://www.gnu.org/s/gettext/ns/messages/1.0"
+           version="1.0">
+  <!-- Invalid: no selector -->
+  <its:translateRule translate="yes"/>
+  <!-- Invalid: no translate -->
+  <its:translateRule selector="/"/>
+
+  <its:translateRule selector="//msg:message/@comment" translate="yes"/>
+  <its:translateRule selector="//msg:note" translate="no"/>
+  <its:translateRule selector="//msg:p[@translatable = 'no']"
+    translate="no"/>
+
+  <!-- Invalid: no selector -->
+  <its:locNoteRule locNoteType="alert"/>
+  <!-- Invalid: no locNoteType -->
+  <its:locNoteRule selector="/"/>
+  <its:locNoteRule selector="//msg:message/*" locNoteType="alert"
+    locNotePointer="../msg:note"/>
+  <its:locNoteRule selector="//msg:code" locNoteType="alert">
+    <its:locNote>This is code</its:locNote>
+  </its:locNoteRule>
+  <its:locNoteRule selector="//msg:message/@comment" locNoteType="alert">
+    <its:locNote>This is a comment</its:locNote>
+  </its:locNoteRule>
+
+  <!-- Invalid: no selector -->
+  <its:withinTextRule withinText="yes"/>
+  <!-- Invalid: no withinText -->
+  <its:withinTextRule selector="/"/>
+  <its:withinTextRule selector="//msg:span | //msg:link" withinText="yes"/>
+
+  <!-- Invalid: no selector -->
+  <its:preserveSpaceRule space="preserve"/>
+  <!-- Invalid: no space -->
+  <its:preserveSpaceRule selector="/"/>
+  <its:preserveSpaceRule selector="//msg:code" space="preserve"/>
+
+  <gt:contextRule selector="//msg:p[@context = 'yes']"
+                  contextPointer="substring-before(., '|')"
+                  textPointer="substring-after(., '|')"/>
+</its:rules>
+EOF
+
+cat <<\EOF >messages.xml
+<?xml version="1.0"?>
+<!DOCTYPE messages PUBLIC "" "" [
+<!ENTITY foo "bar">
+]>
+<messages xmlns="http://www.gnu.org/s/gettext/ns/messages/1.0"
+          xmlns:its="http://www.w3.org/2005/11/its">
+  <message>
+    <p>This is a test message &foo;&gt;&lt;&amp;&quot;"</p>
+  </message>
+  <message>
+    <p its:translate="no">This is a non-translatable message</p>
+  </message>
+  <message>
+    <p>This is a test message, with an <span>element</span> in a <link href="http://www.gnu.org/s/gettext">text</link></p>
+  </message>
+  <message>
+    <code>  $ echo '  ' &gt;&gt; /dev/null
+  $ cat &lt; /dev/yes
+  $ sleep 10 &amp;
+</code>
+  </message>
+  <message comment="This is a comment &lt;&gt;&amp;&quot;">
+    <p>This is a test message, with an attribute</p>
+  </message>
+  <message>
+    <note>
+      This is a localization note
+    </note>
+    <p>This is a test message, with a localization note</p>
+  </message>
+  <message>
+    <p its:locNote="This is a local localization note" its:locNoteType="alert">
+      This is a test message, with a local localization note
+    </p>
+  </message>
+  <message>
+    <!-- empty element, which shouldn't be extracted -->
+    <p></p>
+  </message>
+  <message>
+    <p xml:space="preserve"> This is a message with  space  preserved</p>
+  </message>
+  <message>
+    <p translatable="no">This is a non-translatable string</p>
+  </message>
+  <message its:translate="no">
+    <p>This is a non-translatable string</p>
+  </message>
+  <message>
+    <!-- This is a comment -->
+    <p context="yes">context|A translatable string with a context prefixed</p>
+  </message>
+  <message>
+    <p xml:space="trim"> Leading/trailing  whitespaces are  removed,
+      but not middle  
+    </p>
+  </message>
+</messages>
+EOF
+
+cat <<\EOF >messages.ok
+#. (itstool) path: message/p
+#: messages.xml:8
+msgid "This is a test message &foo;&gt;&lt;&amp;\"\""
+msgstr ""
+
+#. (itstool) path: message/p
+#: messages.xml:14
+msgid "This is a test message, with an <span>element</span> in a <link href=\"http://www.gnu.org/s/gettext\">text</link>"
+msgstr ""
+
+#. This is code
+#. (itstool) path: message/code
+#: messages.xml:17
+#, no-wrap
+msgid ""
+"  $ echo '  ' &gt;&gt; /dev/null\n"
+"  $ cat &lt; /dev/yes\n"
+"  $ sleep 10 &amp;\n"
+msgstr ""
+
+#. This is a comment
+#. (itstool) path: messages/message@comment
+#: messages.xml:22
+msgid "This is a comment &lt;&gt;&amp;&quot;"
+msgstr ""
+
+#. (itstool) path: message/p
+#: messages.xml:23
+msgid "This is a test message, with an attribute"
+msgstr ""
+
+#. This is a localization note
+#. (itstool) path: message/p
+#: messages.xml:29
+msgid "This is a test message, with a localization note"
+msgstr ""
+
+#. This is a local localization note
+#. (itstool) path: message/p
+#: messages.xml:32
+msgid "This is a test message, with a local localization note"
+msgstr ""
+
+#. (itstool) path: message/p
+#: messages.xml:41
+#, no-wrap
+msgid " This is a message with  space  preserved"
+msgstr ""
+
+#. This is a comment
+#. (itstool) path: message/p
+#: messages.xml:51
+msgctxt "context"
+msgid "A translatable string with a context prefixed"
+msgstr ""
+
+#. (itstool) path: message/p
+#: messages.xml:54
+msgid ""
+"Leading/trailing  whitespaces are  removed,\n"
+"      but not middle"
+msgstr ""
+EOF
+
+: ${DIFF=diff}
+
+${XGETTEXT} --itstool --no-wrap --omit-header -o messages.pot messages.xml 2>messages.err || { cat messages.err; exit 1; }
+${DIFF} messages.ok messages.pot
+result=$?
+test $result = 0 || exit $result
+
+# Check if locating rules can work with --directory, and extra ".in"
+# file name extension.
+test -d data || mkdir data
+test -d po || mkdir po
+
+cp messages.xml data/messages.msg.in
+
+cd po
+GETTEXTDATADIR=..
+export GETTEXTDATADIR
+
+${XGETTEXT} --itstool --no-wrap --omit-header --directory=.. -o messages.pot.in data/messages.msg.in 2>messages.err || { cat messages.err; exit 1; }
+sed -e 's!^#: data/messages.msg.in!#: messages.xml!' \
+  < messages.pot.in > messages.pot
+
+${DIFF} ../messages.ok messages.pot
+result=$?
+test $result = 0 || exit $result