Improved debugging python GDB helpers.

Added printing for WebCore::QualifiedName.
Added a new command that will print the path from a WebCore::Node to the root.

The command is really only half-baked, but hopefully will provide a good starting point for other new commands.
(And it did help me track down an SVG bug.)

BUG=none
TEST=none
Patch from Bryan Yeung <bryeung@chromium.org>.

Review URL: http://codereview.chromium.org/598051

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@39215 0039d316-1c4b-4281-b951-d872f2087c98

1 files changed, 76 insertions, 1 deletions

diff --git a/tools/gdb/webkit.py b/tools/gdb/webkit.py
index 2e1cf12..11dfd06 100644
--- a/tools/gdb/webkit.py
+++ b/tools/gdb/webkit.py
@@ -38,7 +38,7 @@ def ustring_to_string(ptr, length=None):
     return string + extra
 
 
-class StringPrinter:
+class StringPrinter(object):
     "Shared code between different string-printing classes"
     def __init__(self, val):
         self.val = val
@@ -74,12 +74,47 @@ class WebCoreStringPrinter(StringPrinter):
                                  self.get_length())
 
 
+class WebCoreQualifiedNamePrinter(StringPrinter):
+    "Print a WebCore::QualifiedName"
+
+    def __init__(self, val):
+        super(WebCoreQualifiedNamePrinter, self).__init__(val)
+        self.prefix_length = 0
+        self.length = 0
+        if self.val['m_impl']:
+            self.prefix_printer = WebCoreStringPrinter(
+                self.val['m_impl']['m_prefix']['m_string'])
+            self.local_name_printer = WebCoreStringPrinter(
+                self.val['m_impl']['m_localName']['m_string'])
+            self.prefix_length = self.prefix_printer.get_length()
+            if self.prefix_length > 0:
+                self.length = (self.prefix_length + 1 +
+                    self.local_name_printer.get_length())
+            else:
+                self.length = self.local_name_printer.get_length()
+
+    def get_length(self):
+        return self.length
+
+    def to_string(self):
+        if self.get_length() == 0:
+            return "(null)"
+        else:
+            if self.prefix_length > 0:
+                return (self.prefix_printer.to_string() + ":" +
+                    self.local_name_printer.to_string())
+            else:
+                return self.local_name_printer.to_string()
+
+
+
 def lookup_function(val):
     """Function used to load pretty printers; will be passed to GDB."""
     lookup_tag = val.type.tag
     printers = {
         "WebCore::AtomicString": WebCoreAtomicStringPrinter,
         "WebCore::String": WebCoreStringPrinter,
+        "WebCore::QualifiedName": WebCoreQualifiedNamePrinter,
     }
     name = val.type.tag
     if name in printers:
@@ -94,3 +129,43 @@ def lookup_function(val):
 
 
 gdb.pretty_printers.append(lookup_function)
+
+
+
+class PrintPathToRootCommand(gdb.Command):
+  """Command for printing WebKit Node trees.
+Usage: printpathtoroot variable_name
+"""
+
+  def __init__(self):
+      super(PrintPathToRootCommand, self).__init__("printpathtoroot",
+          gdb.COMMAND_SUPPORT,
+          gdb.COMPLETE_NONE)
+
+  def invoke(self, arg, from_tty):
+      element_type = gdb.lookup_type('WebCore::Element')
+      node_type = gdb.lookup_type('WebCore::Node')
+      frame = gdb.selected_frame()
+      try:
+          val = gdb.Frame.read_var(frame, arg)
+      except:
+          print "No such variable, or invalid type"
+          return
+
+      target_type = str(val.type.target().strip_typedefs())
+      if target_type == str(node_type):
+          stack = []
+          while val:
+              stack.append([val,
+                  val.cast(element_type.pointer()).dereference()['m_tagName']])
+              val = val.dereference()['m_parent']
+
+          padding = ''
+          while len(stack) > 0:
+              pair = stack.pop()
+              print padding, pair[1], pair[0]
+              padding = padding + '  '
+      else:
+          print 'Sorry: I don\'t know how to deal with %s yet.' % target_type
+
+PrintPathToRootCommand()