GN: Split custom into action and action_foreach

Previously the custom target type implemented two modes: iterate over a list of sources, and run a script once with a set of inputs. This proved a bit confusing since to differentiate these cases you had to either fill in sources or not.

This patch splits that apart into two targets: an action for running a script once, and an action_foreach for running a script over a set of inputs. This makes the differentiation explicit and allows more clear error reporting when you mess it up. I also added additional checks.

BUG=
R=scottmg@chromium.org

Review URL: https://codereview.chromium.org/200923007

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@258342 0039d316-1c4b-4281-b951-d872f2087c98

30 files changed, 648 insertions, 415 deletions

diff --git a/tools/gn/BUILD.gn b/tools/gn/BUILD.gn
index 1c2f162..badfb0b 100644
--- a/tools/gn/BUILD.gn
+++ b/tools/gn/BUILD.gn
@@ -15,6 +15,10 @@ if (!is_gyp) {
 
 static_library("gn_lib") {
   sources = [
+    "action_target_generator.cc",
+    "action_target_generator.h",
+    "action_values.cc",
+    "action_values.h",
     "args.cc",
     "args.h",
     "binary_target_generator.cc",
@@ -69,8 +73,8 @@ static_library("gn_lib") {
     "gyp_binary_target_writer.h",
     "gyp_helper.cc",
     "gyp_helper.h",
-    "gyp_script_target_writer.cc",
-    "gyp_script_target_writer.h",
+    "gyp_action_target_writer.cc",
+    "gyp_action_target_writer.h",
     "gyp_target_writer.cc",
     "gyp_target_writer.h",
     "import_manager.cc",
@@ -90,6 +94,8 @@ static_library("gn_lib") {
     "loader.h",
     "location.cc",
     "location.h",
+    "ninja_action_target_writer.cc",
+    "ninja_action_target_writer.h",
     "ninja_binary_target_writer.cc",
     "ninja_binary_target_writer.h",
     "ninja_build_writer.cc",
@@ -100,8 +106,6 @@ static_library("gn_lib") {
     "ninja_group_target_writer.h",
     "ninja_helper.cc",
     "ninja_helper.h",
-    "ninja_script_target_writer.cc",
-    "ninja_script_target_writer.h",
     "ninja_target_writer.cc",
     "ninja_target_writer.h",
     "ninja_toolchain_writer.cc",
@@ -125,10 +129,6 @@ static_library("gn_lib") {
     "scope.h",
     "scope_per_file_provider.cc",
     "scope_per_file_provider.h",
-    "script_target_generator.cc",
-    "script_target_generator.h",
-    "script_values.cc",
-    "script_values.h",
     "settings.cc",
     "settings.h",
     "setup.cc",
@@ -185,18 +185,18 @@ test("gn_unittests") {
   sources = [
     "builder_unittest.cc",
     "escape_unittest.cc",
-    "file_template_unittest.cc",
     "filesystem_utils_unittest.cc",
+    "file_template_unittest.cc",
     "function_rebase_path_unittest.cc",
+    "gyp_action_target_writer_unittest.cc",
     "gyp_binary_target_writer_unittest.cc",
-    "gyp_script_target_writer_unittest.cc",
     "input_conversion_unittest.cc",
     "label_unittest.cc",
     "loader_unittest.cc",
+    "ninja_action_target_writer_unittest.cc",
     "ninja_binary_target_writer_unittest.cc",
     "ninja_copy_target_writer_unittest.cc",
     "ninja_helper_unittest.cc",
-    "ninja_script_target_writer_unittest.cc",
     "operators_unittest.cc",
     "parser_unittest.cc",
     "path_output_unittest.cc",
diff --git a/tools/gn/action_target_generator.cc b/tools/gn/action_target_generator.cc
new file mode 100644
index 0000000..5f8f959
--- /dev/null
+++ b/tools/gn/action_target_generator.cc
@@ -0,0 +1,154 @@
+// Copyright (c) 2013 The Chromium Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style license that can be
+// found in the LICENSE file.
+
+#include "tools/gn/action_target_generator.h"
+
+#include "tools/gn/build_settings.h"
+#include "tools/gn/err.h"
+#include "tools/gn/filesystem_utils.h"
+#include "tools/gn/parse_tree.h"
+#include "tools/gn/scope.h"
+#include "tools/gn/value.h"
+#include "tools/gn/value_extractors.h"
+#include "tools/gn/variables.h"
+
+namespace {
+
+// Returns true if the list of files looks like it might have a {{ }} pattern
+// in it. Used for error checking.
+bool FileListHasPattern(const Target::FileList& files) {
+  for (size_t i = 0; i < files.size(); i++) {
+    if (files[i].value().find("{{") != std::string::npos &&
+        files[i].value().find("}}") != std::string::npos)
+      return true;
+  }
+  return false;
+}
+
+}  // namespace
+
+ActionTargetGenerator::ActionTargetGenerator(
+    Target* target,
+    Scope* scope,
+    const FunctionCallNode* function_call,
+    Target::OutputType type,
+    Err* err)
+    : TargetGenerator(target, scope, function_call, err),
+      output_type_(type) {
+}
+
+ActionTargetGenerator::~ActionTargetGenerator() {
+}
+
+void ActionTargetGenerator::DoRun() {
+  target_->set_output_type(output_type_);
+
+  FillExternal();
+  if (err_->has_error())
+    return;
+
+  FillSources();
+  if (err_->has_error())
+    return;
+  if (output_type_ == Target::ACTION_FOREACH && target_->sources().empty()) {
+    // Foreach rules must always have some sources to have an effect.
+    *err_ = Err(function_call_, "action_foreach target has no sources.",
+        "If you don't specify any sources, there is nothing to run your\n"
+        "script over.");
+    return;
+  }
+
+  FillSourcePrereqs();
+  if (err_->has_error())
+    return;
+
+  FillScript();
+  if (err_->has_error())
+    return;
+
+  FillScriptArgs();
+  if (err_->has_error())
+    return;
+
+  FillOutputs();
+  if (err_->has_error())
+    return;
+
+  FillDepfile();
+  if (err_->has_error())
+    return;
+
+  CheckOutputs();
+  if (err_->has_error())
+    return;
+
+  // Action outputs don't depend on the current toolchain so we can skip adding
+  // that dependency.
+}
+
+void ActionTargetGenerator::FillScript() {
+  // If this gets called, the target type requires a script, so error out
+  // if it doesn't have one.
+  const Value* value = scope_->GetValue(variables::kScript, true);
+  if (!value) {
+    *err_ = Err(function_call_, "This target type requires a \"script\".");
+    return;
+  }
+  if (!value->VerifyTypeIs(Value::STRING, err_))
+    return;
+
+  target_->action_values().set_script(
+      scope_->GetSourceDir().ResolveRelativeFile(value->string_value()));
+}
+
+void ActionTargetGenerator::FillScriptArgs() {
+  const Value* value = scope_->GetValue(variables::kArgs, true);
+  if (!value)
+    return;
+
+  std::vector<std::string> args;
+  if (!ExtractListOfStringValues(*value, &args, err_))
+    return;
+  target_->action_values().swap_in_args(&args);
+}
+
+void ActionTargetGenerator::FillDepfile() {
+  const Value* value = scope_->GetValue(variables::kDepfile, true);
+  if (!value)
+    return;
+  target_->action_values().set_depfile(
+      scope_->settings()->build_settings()->build_dir().ResolveRelativeFile(
+          value->string_value()));
+}
+
+void ActionTargetGenerator::CheckOutputs() {
+  const Target::FileList& outputs = target_->action_values().outputs();
+  if (outputs.empty()) {
+    *err_ = Err(function_call_, "Action has no outputs.",
+        "If you have no outputs, the build system can not tell when your\n"
+        "script needs to be run.");
+    return;
+  }
+
+  if (output_type_ == Target::ACTION) {
+    // Make sure the outputs for an action have no patterns in them.
+    if (FileListHasPattern(outputs)) {
+      *err_ = Err(function_call_, "Action has patterns in the output.",
+          "An action target should have the outputs completely specified. If\n"
+          "you want to provide a mapping from source to output, use an\n"
+          "\"action_foreach\" target.");
+      return;
+    }
+  } else if (output_type_ == Target::ACTION_FOREACH) {
+    // A foreach target should always have a pattern in the outputs.
+    if (!FileListHasPattern(outputs)) {
+      *err_ = Err(function_call_,
+          "action_foreach should have a pattern in the output.",
+          "An action_foreach target should have a source expansion pattern in\n"
+          "it to map source file to unique output file name. Otherwise, the\n"
+          "build system can't determine when your script needs to be run.");
+      return;
+    }
+  }
+}
diff --git a/tools/gn/action_target_generator.h b/tools/gn/action_target_generator.h
new file mode 100644
index 0000000..aa81c3d
--- /dev/null
+++ b/tools/gn/action_target_generator.h
@@ -0,0 +1,37 @@
+// Copyright (c) 2013 The Chromium Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style license that can be
+// found in the LICENSE file.
+
+#ifndef TOOLS_GN_ACTION_TARGET_GENERATOR_H_
+#define TOOLS_GN_ACTION_TARGET_GENERATOR_H_
+
+#include "base/compiler_specific.h"
+#include "tools/gn/target_generator.h"
+
+// Populates a Target with the values from an action[_foreach] rule.
+class ActionTargetGenerator : public TargetGenerator {
+ public:
+  ActionTargetGenerator(Target* target,
+                        Scope* scope,
+                        const FunctionCallNode* function_call,
+                        Target::OutputType type,
+                        Err* err);
+  virtual ~ActionTargetGenerator();
+
+ protected:
+  virtual void DoRun() OVERRIDE;
+
+ private:
+  void FillScript();
+  void FillScriptArgs();
+  void FillDepfile();
+
+  // Checks for errors in the outputs variable.
+  void CheckOutputs();
+
+  Target::OutputType output_type_;
+
+  DISALLOW_COPY_AND_ASSIGN(ActionTargetGenerator);
+};
+
+#endif  // TOOLS_GN_ACTION_TARGET_GENERATOR_H_
diff --git a/tools/gn/script_values.cc b/tools/gn/action_values.cc
index c5d7989..80bea62 100644
--- a/tools/gn/script_values.cc
+++ b/tools/gn/action_values.cc
@@ -2,10 +2,10 @@
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
-#include "tools/gn/script_values.h"
+#include "tools/gn/action_values.h"
 
-ScriptValues::ScriptValues() {
+ActionValues::ActionValues() {
 }
 
-ScriptValues::~ScriptValues() {
+ActionValues::~ActionValues() {
 }
diff --git a/tools/gn/script_values.h b/tools/gn/action_values.h
index 50219ef..8b883c7 100644
--- a/tools/gn/script_values.h
+++ b/tools/gn/action_values.h
@@ -2,8 +2,8 @@
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
-#ifndef TOOLS_GN_SCRIPT_VALUES_H_
-#define TOOLS_GN_SCRIPT_VALUES_H_
+#ifndef TOOLS_GN_ACTION_VALUES_H_
+#define TOOLS_GN_ACTION_VALUES_H_
 
 #include <string>
 #include <vector>
@@ -11,12 +11,12 @@
 #include "base/basictypes.h"
 #include "tools/gn/source_file.h"
 
-// Holds the values (outputs, args, script name, etc.) for a script-based
-// target.
-class ScriptValues {
+// Holds the values (outputs, args, script name, etc.) for either an action or
+// an action_foreach target.
+class ActionValues {
  public:
-  ScriptValues();
-  ~ScriptValues();
+  ActionValues();
+  ~ActionValues();
 
   // Filename of the script to execute.
   const SourceFile& script() const { return script_; }
@@ -43,7 +43,7 @@ class ScriptValues {
   std::vector<SourceFile> outputs_;
   SourceFile depfile_;
 
-  DISALLOW_COPY_AND_ASSIGN(ScriptValues);
+  DISALLOW_COPY_AND_ASSIGN(ActionValues);
 };
 
-#endif  // TOOLS_GN_SCRIPT_VALUES_H_
+#endif  // TOOLS_GN_ACTION_VALUES_H_
diff --git a/tools/gn/copy_target_generator.cc b/tools/gn/copy_target_generator.cc
index b1b9076..c88b0c4 100644
--- a/tools/gn/copy_target_generator.cc
+++ b/tools/gn/copy_target_generator.cc
@@ -38,7 +38,7 @@ void CopyTargetGenerator::DoRun() {
         "You have to specify at least one file to copy in the \"sources\".");
     return;
   }
-  if (target_->script_values().outputs().size() != 1) {
+  if (target_->action_values().outputs().size() != 1) {
     *err_ = Err(function_call_, "Copy command must have exactly one output.",
         "You must specify exactly one value in the \"outputs\" array for the "
         "destination of the copy\n(see \"gn help copy\"). If there are "
diff --git a/tools/gn/file_template.cc b/tools/gn/file_template.cc
index 92a44a9..ec34993 100644
--- a/tools/gn/file_template.cc
+++ b/tools/gn/file_template.cc
@@ -19,7 +19,7 @@ const char FileTemplate::kSourceFilePart[] = "{{source_file_part}}";
 const char kSourceExpansion_Help[] =
     "How Source Expansion Works\n"
     "\n"
-    "  Source expansion is used for the custom script and copy target types\n"
+    "  Source expansion is used for the action_foreach and copy target types\n"
     "  to map source file names to output file names or arguments.\n"
     "\n"
     "  To perform source expansion in the outputs, GN maps every entry in the\n"
@@ -34,8 +34,8 @@ const char kSourceExpansion_Help[] =
     "  as a static list of literal file names that do not depend on the\n"
     "  sources.\n"
     "\n"
-    "  See \"gn help copy\" and \"gn help custom\" for more on how this is\n"
-    "  applied.\n"
+    "  See \"gn help copy\" and \"gn help action_foreach\" for more on how\n"
+    "  this is applied.\n"
     "\n"
     "Placeholders\n"
     "\n"
@@ -59,7 +59,7 @@ const char kSourceExpansion_Help[] =
     "Examples\n"
     "\n"
     "  Non-varying outputs:\n"
-    "    script(\"hardcoded_outputs\") {\n"
+    "    action(\"hardcoded_outputs\") {\n"
     "      sources = [ \"input1.idl\", \"input2.idl\" ]\n"
     "      outputs = [ \"$target_out_dir/output1.dat\",\n"
     "                  \"$target_out_dir/output2.dat\" ]\n"
@@ -67,7 +67,7 @@ const char kSourceExpansion_Help[] =
     "  The outputs in this case will be the two literal files given.\n"
     "\n"
     "  Varying outputs:\n"
-    "    script(\"varying_outputs\") {\n"
+    "    action_foreach(\"varying_outputs\") {\n"
     "      sources = [ \"input1.idl\", \"input2.idl\" ]\n"
     "      outputs = [ \"$target_out_dir/{{source_name_part}}.h\",\n"
     "                  \"$target_out_dir/{{source_name_part}}.cc\" ]\n"
@@ -96,7 +96,7 @@ FileTemplate::~FileTemplate() {
 
 // static
 FileTemplate FileTemplate::GetForTargetOutputs(const Target* target) {
-  const Target::FileList& outputs = target->script_values().outputs();
+  const Target::FileList& outputs = target->action_values().outputs();
   std::vector<std::string> output_template_args;
   for (size_t i = 0; i < outputs.size(); i++)
     output_template_args.push_back(outputs[i].value());
diff --git a/tools/gn/function_rebase_path.cc b/tools/gn/function_rebase_path.cc
index aefedd5..a167cda 100644
--- a/tools/gn/function_rebase_path.cc
+++ b/tools/gn/function_rebase_path.cc
@@ -211,7 +211,7 @@ const char kRebasePath_Help[] =
     "  foo = rebase_path(\"source/myfile.txt\", \".\", \".\", \"to_system\")\n"
     "\n"
     "  # Typical usage for converting to the build directory for a script.\n"
-    "  custom(\"myscript\") {\n"
+    "  action(\"myscript\") {\n"
     "    # Don't convert sources, GN will automatically convert these to be\n"
     "    # relative to the build directory when it contructs the command\n"
     "    # line for your script.\n"
@@ -224,7 +224,7 @@ const char kRebasePath_Help[] =
     "      rebase_path(\"//mything/data/input.dat\", root_build_dir),\n"
     "      \"--rel\",\n"
     "      rebase_path(\"relative_path.txt\", root_build_dir)\n"
-    "    ]\n"
+    "    ] + sources\n"
     "  }\n";
 
 Value RunRebasePath(Scope* scope,
diff --git a/tools/gn/function_template.cc b/tools/gn/function_template.cc
index 0947305..f726529 100644
--- a/tools/gn/function_template.cc
+++ b/tools/gn/function_template.cc
@@ -58,7 +58,7 @@ const char kTemplate_Help[] =
     "               \"$target_gen_dir/{{source_name_part}}.h\" ]\n"
     "\n"
     "    # Intermediate target to compile IDL to C source.\n"
-    "    custom(\"${target_name}_code_gen\") {\n"
+    "    action_foreach(\"${target_name}_code_gen\") {\n"
     "      # The |sources| will be inherited from the surrounding scope so\n"
     "      # we don't need to redefine it.\n"
     "      script = \"foo.py\"\n"
diff --git a/tools/gn/functions.cc b/tools/gn/functions.cc
index 2443ad9..8d146b2 100644
--- a/tools/gn/functions.cc
+++ b/tools/gn/functions.cc
@@ -574,11 +574,12 @@ struct FunctionInfoInitializer {
     #define INSERT_FUNCTION(command) \
         map[k##command] = FunctionInfo(&Run##command, k##command##_Help);
 
+    INSERT_FUNCTION(Action)
+    INSERT_FUNCTION(ActionForEach)
     INSERT_FUNCTION(Assert)
     INSERT_FUNCTION(Component)
     INSERT_FUNCTION(Config)
     INSERT_FUNCTION(Copy)
-    INSERT_FUNCTION(Custom)
     INSERT_FUNCTION(DeclareArgs)
     INSERT_FUNCTION(Defined)
     INSERT_FUNCTION(ExecScript)
diff --git a/tools/gn/functions.h b/tools/gn/functions.h
index 60eb202..2a5d0a2 100644
--- a/tools/gn/functions.h
+++ b/tools/gn/functions.h
@@ -54,6 +54,22 @@ typedef Value (*NoBlockFunction)(Scope* scope,
                                  const std::vector<Value>& args,
                                  Err* err);
 
+extern const char kAction[];
+extern const char kAction_Help[];
+Value RunAction(Scope* scope,
+                const FunctionCallNode* function,
+                const std::vector<Value>& args,
+                BlockNode* block,
+                Err* err);
+
+extern const char kActionForEach[];
+extern const char kActionForEach_Help[];
+Value RunActionForEach(Scope* scope,
+                       const FunctionCallNode* function,
+                       const std::vector<Value>& args,
+                       BlockNode* block,
+                       Err* err);
+
 extern const char kAssert[];
 extern const char kAssert_Help[];
 Value RunAssert(Scope* scope,
@@ -83,14 +99,6 @@ Value RunCopy(const FunctionCallNode* function,
               Scope* block_scope,
               Err* err);
 
-extern const char kCustom[];
-extern const char kCustom_Help[];
-Value RunCustom(Scope* scope,
-                const FunctionCallNode* function,
-                const std::vector<Value>& args,
-                BlockNode* block,
-                Err* err);
-
 extern const char kDeclareArgs[];
 extern const char kDeclareArgs_Help[];
 Value RunDeclareArgs(Scope* scope,
diff --git a/tools/gn/functions_target.cc b/tools/gn/functions_target.cc
index 8c61f3b..9b47cf74 100644
--- a/tools/gn/functions_target.cc
+++ b/tools/gn/functions_target.cc
@@ -52,6 +52,148 @@ Value ExecuteGenericTarget(const char* target_type,
 
 }  // namespace
 
+// action ----------------------------------------------------------------------
+
+// Common help paragraph on script runtime execution directories.
+#define SCRIPT_EXECUTION_CONTEXT \
+    "  The script will be executed with the given arguments with the current\n"\
+    "  directory being that of the root build directory. If you pass files\n"\
+    "  to your script, see \"gn help to_build_path\" for how to convert\n" \
+    "  file names to be relative to the build directory (file names in the\n" \
+    "  sources, outputs, and source_prereqs will be all treated as relative\n" \
+    "  to the current build file and converted as needed automatically).\n"
+
+// Common help paragraph on script output directories.
+#define SCRIPT_EXECUTION_OUTPUTS \
+    "  All output files must be inside the output directory of the build.\n" \
+    "  You would generally use |$target_out_dir| or |$target_gen_dir| to\n" \
+    "  reference the output or generated intermediate file directories,\n" \
+    "  respectively.\n"
+
+const char kAction[] = "action";
+const char kAction_Help[] =
+    "action: Declare a target that runs a script a single time.\n"
+    "\n"
+    "  This target type allows you to run a script a single time to produce\n"
+    "  or more output files. If you want to run a script once for each of a\n"
+    "  set of input files, see \"gn help action_foreach\".\n"
+    "\n"
+    "  In an action the \"sources\" and \"source_prereqs\" are treated the\n"
+    "  same: they're both input dependencies on script execution with no\n"
+    "  special handling. If you want to pass the sources to your script, you\n"
+    "  must do so explicitly by including them in the \"args\".\n"
+    "\n"
+    "  It is recommended you put inputs to your script in the \"sources\"\n"
+    "  variable, and stuff like other Python files required to run your\n"
+    "  script in the \"source_prereqs\" variable.\n"
+    "\n"
+    "  You should specify files created by your script by specifying them in\n"
+    "  the \"outputs\".\n"
+    "\n"
+    SCRIPT_EXECUTION_CONTEXT
+    "\n"
+    "File name handling\n"
+    "\n"
+    SCRIPT_EXECUTION_OUTPUTS
+    "\n"
+    "Variables\n"
+    "\n"
+    "  args, data, datadeps, depfile, deps, outputs*, script*,\n"
+    "  source_prereqs, sources\n"
+    "  * = required\n"
+    "\n"
+    "Example\n"
+    "\n"
+    "  action(\"run_this_guy_once\") {\n"
+    "    script = \"doprocessing.py\"\n"
+    "    sources = [ \"my_configuration.txt\" ]\n"
+    "    outputs = [ \"$target_gen_dir/insightful_output.txt\" ]\n"
+    "\n"
+    "    # Our script imports this Python file so we want to rebuild if it\n"
+    "    # changes.\n"
+    "    source_prereqs = [ \"helper_library.py\" ]\n"
+    "\n"
+    "    # Note that we have to manually pass the sources to our script if\n"
+    "    # the script needs them as inputs.\n"
+    "    args = [ \"--out\", to_build_path(target_gen_dir) ] + sources\n"
+    "  }\n";
+
+Value RunAction(Scope* scope,
+                const FunctionCallNode* function,
+                const std::vector<Value>& args,
+                BlockNode* block,
+                Err* err) {
+  return ExecuteGenericTarget(functions::kAction, scope, function, args,
+                              block, err);
+}
+
+// action_foreach --------------------------------------------------------------
+
+const char kActionForEach[] = "action_foreach";
+const char kActionForEach_Help[] =
+    "action_foreach: Run a script over a set of input files.\n"
+    "\n"
+    "  This target type allows you to run a script once-per-file over a set\n"
+    "  of sources. If you want to run a script once that takes many files as\n"
+    "  input, see \"gn help action\".\n"
+    "\n"
+    "  The script will be run once per file in the \"sources\" variable. The\n"
+    "  \"outputs\" variable should specify one or more files with a source\n"
+    "  expansion pattern in it (see \"gn help source_expansion\"). The output\n"
+    "  file(s) for each script invocation should be unique. Normally you\n"
+    "  use \"{{source_name_part}}\" in each output file.\n"
+    "\n"
+    "  If your script takes additional data as input, such as a shared\n"
+    "  configuration file or a Python module it uses, those files should be\n"
+    "  listed in the \"source_prereqs\" variable. These files are treated as\n"
+    "  dependencies of each script invocation.\n"
+    "\n"
+    SCRIPT_EXECUTION_CONTEXT
+    "\n"
+    "File name handling\n"
+    "\n"
+    SCRIPT_EXECUTION_OUTPUTS
+    "\n"
+    "Variables\n"
+    "\n"
+    "  args, data, datadeps, depfile, deps, outputs*, script*,\n"
+    "  source_prereqs, sources*\n"
+    "  * = required\n"
+    "\n"
+    "Example\n"
+    "\n"
+    "  # Runs the script over each IDL file. The IDL script will generate\n"
+    "  # both a .cc and a .h file for each input.\n"
+    "  action_foreach(\"my_idl\") {\n"
+    "    script = \"idl_processor.py\"\n"
+    "    sources = [ \"foo.idl\", \"bar.idl\" ]\n"
+    "\n"
+    "    # Our script reads this file each time, so we need to list is as a\n"
+    "    # dependency so we can rebuild if it changes.\n"
+    "    source_prereqs = [ \"my_configuration.txt\" ]\n"
+    "\n"
+    "    # Transformation from source file name to output file names.\n"
+    "    outputs = [ \"$target_gen_dir/{{source_name_part}}.h\",\n"
+    "                \"$target_gen_dir/{{source_name_part}}.cc\" ]\n"
+    "\n"
+    "    # Note that since \"args\" is opaque to GN, if you specify paths\n"
+    "    # here, you will need to convert it to be relative to the build\n"
+    "    # directory using \"to_build_path()\".\n"
+    "    args = [ \"{{source}}\",\n"
+    "             \"-o\",\n"
+    "             to_build_path(relative_target_gen_dir) + \"/\" +\n"
+    "                 {{source_name_part}}.h\" ]\n"
+    "  }\n"
+    "\n";
+Value RunActionForEach(Scope* scope,
+                       const FunctionCallNode* function,
+                       const std::vector<Value>& args,
+                       BlockNode* block,
+                       Err* err) {
+  return ExecuteGenericTarget(functions::kActionForEach, scope, function, args,
+                              block, err);
+}
+
 // component -------------------------------------------------------------------
 
 const char kComponent[] = "component";
@@ -167,91 +309,6 @@ Value RunCopy(const FunctionCallNode* function,
   return Value();
 }
 
-// custom ----------------------------------------------------------------------
-
-const char kCustom[] = "custom";
-const char kCustom_Help[] =
-    "custom: Declare a script-generated target.\n"
-    "\n"
-    "  This target type allows you to run a script over a set of source\n"
-    "  files and generate a set of output files.\n"
-    "\n"
-    "  The script will be executed with the given arguments with the current\n"
-    "  directory being that of the root build directory. If you pass files\n"
-    "  to your script, see \"gn help to_build_path\" for how to convert\n"
-    "  file names to be relative to the build directory (file names in the\n"
-    "  sources, outputs, and source_prereqs will be all treated as relative\n"
-    "  to the current build file and converted as needed automatically).\n"
-    "\n"
-    "  There are two modes. The first mode is the \"per-file\" mode where you\n"
-    "  specify a list of sources and the script is run once for each one as a\n"
-    "  build rule. In this case, each file specified in the |outputs|\n"
-    "  variable must be unique when applied to each source file (normally you\n"
-    "  would reference |{{source_name_part}}| from within each one) or the\n"
-    "  build system will get confused about how to build those files. You\n"
-    "  should use the |source_prereqs| variable to list all additional\n"
-    "  dependencies of your script: these will be added as dependencies for\n"
-    "  each build step.\n"
-    "\n"
-    "  The second mode is when you just want to run a script once rather than\n"
-    "  as a general rule over a set of files. In this case you don't list any\n"
-    "  sources. Dependencies of your script are specified only in the\n"
-    "  |source_prereqs| variable and your |outputs| variable should just list\n"
-    "  all outputs.\n"
-    "\n"
-    "File name handling\n"
-    "\n"
-    "  All output files must be inside the output directory of the build.\n"
-    "  You would generally use |$target_out_dir| or |$target_gen_dir| to\n"
-    "  reference the output or generated intermediate file directories,\n"
-    "  respectively.\n"
-    "\n"
-    "  You can specify a mapping from source files to output files using\n"
-    "  source expansion (see \"gn help source_expansion\"). The placeholders\n"
-    "  will look like \"{{source}}\", for example, and can appear in\n"
-    "  either the outputs or the args lists.\n"
-    "\n"
-    "Variables\n"
-    "\n"
-    "  args, deps, outputs, script*, source_prereqs, sources\n"
-    "  * = required\n"
-    "\n"
-    "Examples\n"
-    "\n"
-    "  # Runs the script over each IDL file. The IDL script will generate\n"
-    "  # both a .cc and a .h file for each input.\n"
-    "  custom(\"general_rule\") {\n"
-    "    script = \"idl_processor.py\"\n"
-    "    sources = [ \"foo.idl\", \"bar.idl\" ]\n"
-    "    source_prereqs = [ \"my_configuration.txt\" ]\n"
-    "    outputs = [ \"$target_gen_dir/{{source_name_part}}.h\",\n"
-    "                \"$target_gen_dir/{{source_name_part}}.cc\" ]\n"
-    "\n"
-    "    # Note that since \"args\" is opaque to GN, if you specify paths\n"
-    "    # here, you will need to convert it to be relative to the build\n"
-    "    # directory using \"to_build_path()\".\n"
-    "    args = [ \"{{source}}\",\n"
-    "             \"-o\",\n"
-    "             to_build_path(relative_target_gen_dir) + \"/\" +\n"
-    "                 {{source_name_part}}.h\" ]\n"
-    "  }\n"
-    "\n"
-    "  custom(\"just_run_this_guy_once\") {\n"
-    "    script = \"doprocessing.py\"\n"
-    "    source_prereqs = [ \"my_configuration.txt\" ]\n"
-    "    outputs = [ \"$target_gen_dir/insightful_output.txt\" ]\n"
-    "    args = [ \"--output_dir\", to_build_path(target_gen_dir) ]\n"
-    "  }\n";
-
-Value RunCustom(Scope* scope,
-                const FunctionCallNode* function,
-                const std::vector<Value>& args,
-                BlockNode* block,
-                Err* err) {
-  return ExecuteGenericTarget(functions::kCustom, scope, function, args,
-                              block, err);
-}
-
 // executable ------------------------------------------------------------------
 
 const char kExecutable[] = "executable";
diff --git a/tools/gn/gn.gyp b/tools/gn/gn.gyp
index 0670ad4..fe305c1 100644
--- a/tools/gn/gn.gyp
+++ b/tools/gn/gn.gyp
@@ -10,6 +10,10 @@
         '../../base/base.gyp:base',
       ],
       'sources': [
+        'action_target_generator.cc',
+        'action_target_generator.h',
+        'action_values.cc',
+        'action_values.h',
         'args.cc',
         'args.h',
         'binary_target_generator.cc',
@@ -60,12 +64,12 @@
         'function_write_file.cc',
         'group_target_generator.cc',
         'group_target_generator.h',
+        'gyp_action_target_writer.cc',
+        'gyp_action_target_writer.h',
         'gyp_binary_target_writer.cc',
         'gyp_binary_target_writer.h',
         'gyp_helper.cc',
         'gyp_helper.h',
-        'gyp_script_target_writer.cc',
-        'gyp_script_target_writer.h',
         'gyp_target_writer.cc',
         'gyp_target_writer.h',
         'import_manager.cc',
@@ -85,6 +89,8 @@
         'loader.h',
         'location.cc',
         'location.h',
+        'ninja_action_target_writer.cc',
+        'ninja_action_target_writer.h',
         'ninja_binary_target_writer.cc',
         'ninja_binary_target_writer.h',
         'ninja_build_writer.cc',
@@ -95,8 +101,6 @@
         'ninja_group_target_writer.h',
         'ninja_helper.cc',
         'ninja_helper.h',
-        'ninja_script_target_writer.cc',
-        'ninja_script_target_writer.h',
         'ninja_target_writer.cc',
         'ninja_target_writer.h',
         'ninja_toolchain_writer.cc',
@@ -120,10 +124,6 @@
         'scope.h',
         'scope_per_file_provider.cc',
         'scope_per_file_provider.h',
-        'script_target_generator.cc',
-        'script_target_generator.h',
-        'script_values.cc',
-        'script_values.h',
         'settings.cc',
         'settings.h',
         'setup.cc',
@@ -174,18 +174,18 @@
       'sources': [
         'builder_unittest.cc',
         'escape_unittest.cc',
-        'file_template_unittest.cc',
         'filesystem_utils_unittest.cc',
+        'file_template_unittest.cc',
         'function_rebase_path_unittest.cc',
+        'gyp_action_target_writer_unittest.cc',
         'gyp_binary_target_writer_unittest.cc',
-        'gyp_script_target_writer_unittest.cc',
         'input_conversion_unittest.cc',
         'label_unittest.cc',
         'loader_unittest.cc',
+        'ninja_action_target_writer_unittest.cc',
         'ninja_binary_target_writer_unittest.cc',
-        'ninja_helper_unittest.cc',
         'ninja_copy_target_writer_unittest.cc',
-        'ninja_script_target_writer_unittest.cc',
+        'ninja_helper_unittest.cc',
         'operators_unittest.cc',
         'parser_unittest.cc',
         'path_output_unittest.cc',
diff --git a/tools/gn/gyp_script_target_writer.cc b/tools/gn/gyp_action_target_writer.cc
index 472a23b..7df2b9d 100644
--- a/tools/gn/gyp_script_target_writer.cc
+++ b/tools/gn/gyp_action_target_writer.cc
@@ -2,7 +2,7 @@
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
-#include "tools/gn/gyp_script_target_writer.h"
+#include "tools/gn/gyp_action_target_writer.h"
 
 #include "tools/gn/builder_record.h"
 #include "tools/gn/err.h"
@@ -11,11 +11,11 @@
 #include "tools/gn/settings.h"
 #include "tools/gn/target.h"
 
-// Write script targets as GYP actions that just invoke Ninja. This allows us
-// to not have to worry about duplicating the precise GN script execution
+// Write action targets as GYP actions that just invoke Ninja. This allows us
+// to not have to worry about duplicating the precise GN action execution
 // semantices in GYP for each platform (GYP varies a bit).
 
-GypScriptTargetWriter::GypScriptTargetWriter(const TargetGroup& group,
+GypActionTargetWriter::GypActionTargetWriter(const TargetGroup& group,
                                              const Toolchain* toolchain,
                                              const SourceDir& gyp_dir,
                                              std::ostream& out)
@@ -23,14 +23,14 @@ GypScriptTargetWriter::GypScriptTargetWriter(const TargetGroup& group,
                       gyp_dir, out) {
 }
 
-GypScriptTargetWriter::~GypScriptTargetWriter() {
+GypActionTargetWriter::~GypActionTargetWriter() {
 }
 
-void GypScriptTargetWriter::Run() {
+void GypActionTargetWriter::Run() {
   int indent = 4;
   std::string name = helper_.GetNameForTarget(target_);
 
-  // Put the ninja build for this script target in this directory.
+  // Put the ninja build for this action target in this directory.
   SourceDir ninja_dir(GetTargetOutputDir(target_).value() + name + "_ninja/");
 
   Indent(indent) << "{\n";
@@ -57,7 +57,7 @@ void GypScriptTargetWriter::Run() {
   Indent(indent) << "},\n";
 }
 
-void GypScriptTargetWriter::WriteActionInputs(int indent) {
+void GypActionTargetWriter::WriteActionInputs(int indent) {
   Indent(indent) << "'inputs': [\n";
 
   // Write everything that should be considered an input for dependency
@@ -79,13 +79,13 @@ void GypScriptTargetWriter::WriteActionInputs(int indent) {
   Indent(indent) << "],\n";
 }
 
-void GypScriptTargetWriter::WriteActionOutputs(int indent) {
+void GypActionTargetWriter::WriteActionOutputs(int indent) {
   Indent(indent) << "'outputs': [\n";
 
   const Target::FileList& sources = target_->sources();
   if (sources.empty()) {
     // Just write outputs directly if there are no sources.
-    const Target::FileList& output = target_->script_values().outputs();
+    const Target::FileList& output = target_->action_values().outputs();
     for (size_t output_i = 0; output_i < output.size(); output_i++) {
       Indent(indent + kExtraIndent) << "'";
       path_output_.WriteFile(out_, output[output_i]);
diff --git a/tools/gn/gyp_script_target_writer.h b/tools/gn/gyp_action_target_writer.h
index 9f277f1..1ef3a7c 100644
--- a/tools/gn/gyp_script_target_writer.h
+++ b/tools/gn/gyp_action_target_writer.h
@@ -2,21 +2,21 @@
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
-#ifndef TOOLS_GN_GYP_SCRIPT_TARGET_WRITER_H_
-#define TOOLS_GN_GYP_SCRIPT_TARGET_WRITER_H_
+#ifndef TOOLS_GN_GYP_ACTION_TARGET_WRITER_H_
+#define TOOLS_GN_GYP_ACTION_TARGET_WRITER_H_
 
 #include "base/compiler_specific.h"
 #include "tools/gn/gyp_target_writer.h"
 #include "tools/gn/target.h"
 #include "tools/gn/toolchain.h"
 
-class GypScriptTargetWriter : public GypTargetWriter {
+class GypActionTargetWriter : public GypTargetWriter {
  public:
-  GypScriptTargetWriter(const TargetGroup& group,
+  GypActionTargetWriter(const TargetGroup& group,
                         const Toolchain* toolchain,
                         const SourceDir& gyp_dir,
                         std::ostream& out);
-  virtual ~GypScriptTargetWriter();
+  virtual ~GypActionTargetWriter();
 
   virtual void Run() OVERRIDE;
 
@@ -24,7 +24,7 @@ class GypScriptTargetWriter : public GypTargetWriter {
   void WriteActionInputs(int indent);
   void WriteActionOutputs(int indent);
 
-  DISALLOW_COPY_AND_ASSIGN(GypScriptTargetWriter);
+  DISALLOW_COPY_AND_ASSIGN(GypActionTargetWriter);
 };
 
-#endif  // TOOLS_GN_GYP_SCRIPT_TARGET_WRITER_H_
+#endif  // TOOLS_GN_GYP_ACTION_TARGET_WRITER_H_
diff --git a/tools/gn/gyp_script_target_writer_unittest.cc b/tools/gn/gyp_action_target_writer_unittest.cc
index ed07a5f..14c2930 100644
--- a/tools/gn/gyp_script_target_writer_unittest.cc
+++ b/tools/gn/gyp_action_target_writer_unittest.cc
@@ -4,20 +4,20 @@
 
 #include "testing/gtest/include/gtest/gtest.h"
 #include "tools/gn/builder_record.h"
-#include "tools/gn/gyp_script_target_writer.h"
+#include "tools/gn/gyp_action_target_writer.h"
 #include "tools/gn/test_with_scope.h"
 
-TEST(GypScriptTargetWriter, Run) {
+TEST(GypActionTargetWriter, Run) {
   TestWithScope setup;
   setup.build_settings()->SetBuildDir(SourceDir("//out/Debug/"));
   scoped_ptr<Target> target(
       new Target(setup.settings(), Label(SourceDir("//foo/"), "bar")));
-  target->set_output_type(Target::CUSTOM);
+  target->set_output_type(Target::ACTION);
 
   target->sources().push_back(SourceFile("//foo/input1.txt"));
   target->sources().push_back(SourceFile("//foo/input2.txt"));
 
-  target->script_values().outputs().push_back(
+  target->action_values().outputs().push_back(
       SourceFile("//out/Debug/{{source_file_part}}.out"));
 
   BuilderRecord record(BuilderRecord::ITEM_TARGET, target->label());
@@ -28,7 +28,7 @@ TEST(GypScriptTargetWriter, Run) {
   setup.settings()->set_target_os(Settings::WIN);
 
   std::ostringstream out;
-  GypScriptTargetWriter writer(group, setup.toolchain(),
+  GypActionTargetWriter writer(group, setup.toolchain(),
                                SourceDir("//out/gn_gyp/"), out);
   writer.Run();
 
diff --git a/tools/gn/gyp_target_writer.cc b/tools/gn/gyp_target_writer.cc
index 0f362d4..789b6b0 100644
--- a/tools/gn/gyp_target_writer.cc
+++ b/tools/gn/gyp_target_writer.cc
@@ -11,8 +11,8 @@
 #include "tools/gn/build_settings.h"
 #include "tools/gn/builder_record.h"
 #include "tools/gn/filesystem_utils.h"
+#include "tools/gn/gyp_action_target_writer.h"
 #include "tools/gn/gyp_binary_target_writer.h"
-#include "tools/gn/gyp_script_target_writer.h"
 #include "tools/gn/scheduler.h"
 #include "tools/gn/settings.h"
 #include "tools/gn/target.h"
@@ -77,8 +77,9 @@ void GypTargetWriter::WriteFile(const SourceFile& gyp_file,
     switch (cur->output_type()) {
       case Target::COPY_FILES:
         break;  // TODO(brettw)
-      case Target::CUSTOM: {
-        GypScriptTargetWriter writer(targets[i], debug_toolchain,
+      case Target::ACTION:
+      case Target::ACTION_FOREACH: {
+        GypActionTargetWriter writer(targets[i], debug_toolchain,
                                      gyp_file.GetDir(), file);
         writer.Run();
         break;
diff --git a/tools/gn/ninja_script_target_writer.cc b/tools/gn/ninja_action_target_writer.cc
index f2004e3..fef58ac 100644
--- a/tools/gn/ninja_script_target_writer.cc
+++ b/tools/gn/ninja_action_target_writer.cc
@@ -2,7 +2,7 @@
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
-#include "tools/gn/ninja_script_target_writer.h"
+#include "tools/gn/ninja_action_target_writer.h"
 
 #include "base/strings/string_util.h"
 #include "tools/gn/err.h"
@@ -10,7 +10,7 @@
 #include "tools/gn/string_utils.h"
 #include "tools/gn/target.h"
 
-NinjaScriptTargetWriter::NinjaScriptTargetWriter(const Target* target,
+NinjaActionTargetWriter::NinjaActionTargetWriter(const Target* target,
                                                  const Toolchain* toolchain,
                                                  std::ostream& out)
     : NinjaTargetWriter(target, toolchain, out),
@@ -19,30 +19,32 @@ NinjaScriptTargetWriter::NinjaScriptTargetWriter(const Target* target,
           ESCAPE_NONE, false) {
 }
 
-NinjaScriptTargetWriter::~NinjaScriptTargetWriter() {
+NinjaActionTargetWriter::~NinjaActionTargetWriter() {
 }
 
-void NinjaScriptTargetWriter::Run() {
-  FileTemplate args_template(target_->script_values().args());
+void NinjaActionTargetWriter::Run() {
+  FileTemplate args_template(target_->action_values().args());
   std::string custom_rule_name = WriteRuleDefinition(args_template);
   std::string implicit_deps = GetSourcesImplicitDeps();
 
   // Collects all output files for writing below.
   std::vector<OutputFile> output_files;
 
-  if (has_sources()) {
+  if (target_->output_type() == Target::ACTION_FOREACH) {
     // Write separate build lines for each input source file.
     WriteSourceRules(custom_rule_name, implicit_deps, args_template,
                      &output_files);
   } else {
-    // No sources, write a rule that invokes the script once with the
-    // outputs as outputs, and the data as inputs.
+    DCHECK(target_->output_type() == Target::ACTION);
+
+    // Write a rule that invokes the script once with the outputs as outputs,
+    // and the data as inputs.
     out_ << "build";
-    if (target_->script_values().has_depfile()) {
+    if (target_->action_values().has_depfile()) {
       out_ << " ";
       WriteDepfile(SourceFile());
     }
-    const Target::FileList& outputs = target_->script_values().outputs();
+    const Target::FileList& outputs = target_->action_values().outputs();
     for (size_t i = 0; i < outputs.size(); i++) {
       OutputFile output_path(
           RemovePrefix(outputs[i].value(),
@@ -51,8 +53,21 @@ void NinjaScriptTargetWriter::Run() {
       out_ << " ";
       path_output_.WriteFile(out_, output_path);
     }
-    out_ << ": " << custom_rule_name << implicit_deps << std::endl;
-    if (target_->script_values().has_depfile()) {
+
+    out_ << ": " << custom_rule_name << implicit_deps;
+
+    // In the case of running the script once, we allow you to write the input
+    // dependencies in both sources and source_prereqs. source_prereqs are
+    // already in the implicit deps written above, but the sources aren't
+    // (since treating the sources this was is unique to an action).
+    const Target::FileList& sources = target_->sources();
+    for (size_t i = 0; i < sources.size(); i++) {
+      out_ << " ";
+      path_output_.WriteFile(out_, sources[i]);
+    }
+    out_ << std::endl;
+
+    if (target_->action_values().has_depfile()) {
       out_ << "  depfile = ";
       WriteDepfile(SourceFile());
       out_ << std::endl;
@@ -63,7 +78,7 @@ void NinjaScriptTargetWriter::Run() {
   WriteStamp(output_files);
 }
 
-std::string NinjaScriptTargetWriter::WriteRuleDefinition(
+std::string NinjaActionTargetWriter::WriteRuleDefinition(
     const FileTemplate& args_template) {
   // Make a unique name for this rule.
   //
@@ -90,7 +105,7 @@ std::string NinjaScriptTargetWriter::WriteRuleDefinition(
     // python without requiring this gyp_win_tool thing.
     out_ << " gyp-win-tool action-wrapper environment.x86 " << rspfile
          << std::endl;
-    out_ << "  description = CUSTOM " << target_label << std::endl;
+    out_ << "  description = ACTION " << target_label << std::endl;
     out_ << "  restat = 1" << std::endl;
     out_ << "  rspfile = " << rspfile << std::endl;
 
@@ -98,7 +113,7 @@ std::string NinjaScriptTargetWriter::WriteRuleDefinition(
     out_ << "  rspfile_content = ";
     path_output_.WriteFile(out_, settings_->build_settings()->python_path());
     out_ << " ";
-    path_output_.WriteFile(out_, target_->script_values().script());
+    path_output_.WriteFile(out_, target_->action_values().script());
     args_template.WriteWithNinjaExpansions(out_);
     out_ << std::endl;
   } else {
@@ -107,10 +122,10 @@ std::string NinjaScriptTargetWriter::WriteRuleDefinition(
     out_ << "  command = ";
     path_output_.WriteFile(out_, settings_->build_settings()->python_path());
     out_ << " ";
-    path_output_.WriteFile(out_, target_->script_values().script());
+    path_output_.WriteFile(out_, target_->action_values().script());
     args_template.WriteWithNinjaExpansions(out_);
     out_ << std::endl;
-    out_ << "  description = CUSTOM " << target_label << std::endl;
+    out_ << "  description = ACTION " << target_label << std::endl;
     out_ << "  restat = 1" << std::endl;
   }
 
@@ -118,7 +133,7 @@ std::string NinjaScriptTargetWriter::WriteRuleDefinition(
   return custom_rule_name;
 }
 
-void NinjaScriptTargetWriter::WriteArgsSubstitutions(
+void NinjaActionTargetWriter::WriteArgsSubstitutions(
     const SourceFile& source,
     const FileTemplate& args_template) {
   std::ostringstream source_file_stream;
@@ -132,7 +147,7 @@ void NinjaScriptTargetWriter::WriteArgsSubstitutions(
       out_, source_file_stream.str(), template_escape_options);
 }
 
-void NinjaScriptTargetWriter::WriteSourceRules(
+void NinjaActionTargetWriter::WriteSourceRules(
     const std::string& custom_rule_name,
     const std::string& implicit_deps,
     const FileTemplate& args_template,
@@ -155,7 +170,7 @@ void NinjaScriptTargetWriter::WriteSourceRules(
     if (args_template.has_substitutions())
       WriteArgsSubstitutions(sources[i], args_template);
 
-    if (target_->script_values().has_depfile()) {
+    if (target_->action_values().has_depfile()) {
       out_ << "  depfile = ";
       WriteDepfile(sources[i]);
       out_ << std::endl;
@@ -163,7 +178,7 @@ void NinjaScriptTargetWriter::WriteSourceRules(
   }
 }
 
-void NinjaScriptTargetWriter::WriteStamp(
+void NinjaActionTargetWriter::WriteStamp(
     const std::vector<OutputFile>& output_files) {
   out_ << "build ";
   path_output_.WriteFile(out_, helper_.GetTargetOutputFile(target_));
@@ -177,13 +192,13 @@ void NinjaScriptTargetWriter::WriteStamp(
   out_ << std::endl;
 }
 
-void NinjaScriptTargetWriter::WriteOutputFilesForBuildLine(
+void NinjaActionTargetWriter::WriteOutputFilesForBuildLine(
     const FileTemplate& output_template,
     const SourceFile& source,
     std::vector<OutputFile>* output_files) {
   // If there is a depfile specified we need to list it as the first output as
   // that is what ninja will expect the depfile to refer to itself as.
-  if (target_->script_values().has_depfile()) {
+  if (target_->action_values().has_depfile()) {
     out_ << " ";
     WriteDepfile(source);
   }
@@ -197,16 +212,16 @@ void NinjaScriptTargetWriter::WriteOutputFilesForBuildLine(
   }
 }
 
-void NinjaScriptTargetWriter::WriteDepfile(const SourceFile& source) {
+void NinjaActionTargetWriter::WriteDepfile(const SourceFile& source) {
   std::vector<std::string> result;
   GetDepfileTemplate().ApplyString(source.value(), &result);
   path_output_.WriteFile(out_, OutputFile(result[0]));
 }
 
-FileTemplate NinjaScriptTargetWriter::GetDepfileTemplate() const {
+FileTemplate NinjaActionTargetWriter::GetDepfileTemplate() const {
   std::vector<std::string> template_args;
   std::string depfile_relative_to_build_dir =
-      RemovePrefix(target_->script_values().depfile().value(),
+      RemovePrefix(target_->action_values().depfile().value(),
                    settings_->build_settings()->build_dir().value());
   template_args.push_back(depfile_relative_to_build_dir);
   return FileTemplate(template_args);
diff --git a/tools/gn/ninja_script_target_writer.h b/tools/gn/ninja_action_target_writer.h
index e32a4a6..e5ece40 100644
--- a/tools/gn/ninja_script_target_writer.h
+++ b/tools/gn/ninja_action_target_writer.h
@@ -2,8 +2,8 @@
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
-#ifndef TOOLS_GN_NINJA_SCRIPT_TARGET_WRITER_H_
-#define TOOLS_GN_NINJA_SCRIPT_TARGET_WRITER_H_
+#ifndef TOOLS_GN_NINJA_ACTION_TARGET_WRITER_H_
+#define TOOLS_GN_NINJA_ACTION_TARGET_WRITER_H_
 
 #include <vector>
 
@@ -14,22 +14,22 @@
 class FileTemplate;
 class OutputFile;
 
-// Writes a .ninja file for a custom script target type.
-class NinjaScriptTargetWriter : public NinjaTargetWriter {
+// Writes a .ninja file for a action target type.
+class NinjaActionTargetWriter : public NinjaTargetWriter {
  public:
-  NinjaScriptTargetWriter(const Target* target,
+  NinjaActionTargetWriter(const Target* target,
                           const Toolchain* toolchain,
                           std::ostream& out);
-  virtual ~NinjaScriptTargetWriter();
+  virtual ~NinjaActionTargetWriter();
 
   virtual void Run() OVERRIDE;
 
  private:
-  FRIEND_TEST_ALL_PREFIXES(NinjaScriptTargetWriter,
+  FRIEND_TEST_ALL_PREFIXES(NinjaActionTargetWriter,
                            WriteOutputFilesForBuildLine);
-  FRIEND_TEST_ALL_PREFIXES(NinjaScriptTargetWriter,
+  FRIEND_TEST_ALL_PREFIXES(NinjaActionTargetWriter,
                            WriteOutputFilesForBuildLineWithDepfile);
-  FRIEND_TEST_ALL_PREFIXES(NinjaScriptTargetWriter,
+  FRIEND_TEST_ALL_PREFIXES(NinjaActionTargetWriter,
                            WriteArgsSubstitutions);
 
   bool has_sources() const { return !target_->sources().empty(); }
@@ -77,7 +77,7 @@ class NinjaScriptTargetWriter : public NinjaTargetWriter {
   // computing intermediate strings.
   PathOutput path_output_no_escaping_;
 
-  DISALLOW_COPY_AND_ASSIGN(NinjaScriptTargetWriter);
+  DISALLOW_COPY_AND_ASSIGN(NinjaActionTargetWriter);
 };
 
-#endif  // TOOLS_GN_NINJA_SCRIPT_TARGET_WRITER_H_
+#endif  // TOOLS_GN_NINJA_ACTION_TARGET_WRITER_H_
diff --git a/tools/gn/ninja_script_target_writer_unittest.cc b/tools/gn/ninja_action_target_writer_unittest.cc
index 6319dff..c1aa6f4 100644
--- a/tools/gn/ninja_script_target_writer_unittest.cc
+++ b/tools/gn/ninja_action_target_writer_unittest.cc
@@ -7,21 +7,21 @@
 
 #include "testing/gtest/include/gtest/gtest.h"
 #include "tools/gn/file_template.h"
-#include "tools/gn/ninja_script_target_writer.h"
+#include "tools/gn/ninja_action_target_writer.h"
 #include "tools/gn/test_with_scope.h"
 
-TEST(NinjaScriptTargetWriter, WriteOutputFilesForBuildLine) {
+TEST(NinjaActionTargetWriter, WriteOutputFilesForBuildLine) {
   TestWithScope setup;
   setup.build_settings()->SetBuildDir(SourceDir("//out/Debug/"));
   Target target(setup.settings(), Label(SourceDir("//foo/"), "bar"));
 
-  target.script_values().outputs().push_back(
+  target.action_values().outputs().push_back(
       SourceFile("//out/Debug/gen/a b{{source_name_part}}.h"));
-  target.script_values().outputs().push_back(
+  target.action_values().outputs().push_back(
       SourceFile("//out/Debug/gen/{{source_name_part}}.cc"));
 
   std::ostringstream out;
-  NinjaScriptTargetWriter writer(&target, setup.toolchain(), out);
+  NinjaActionTargetWriter writer(&target, setup.toolchain(), out);
 
   FileTemplate output_template = writer.GetOutputTemplate();
 
@@ -36,20 +36,20 @@ TEST(NinjaScriptTargetWriter, WriteOutputFilesForBuildLine) {
   EXPECT_EQ(" gen/a$ bbar.h gen/bar.cc", out_str);
 }
 
-TEST(NinjaScriptTargetWriter, WriteOutputFilesForBuildLineWithDepfile) {
+TEST(NinjaActionTargetWriter, WriteOutputFilesForBuildLineWithDepfile) {
   TestWithScope setup;
   setup.build_settings()->SetBuildDir(SourceDir("//out/Debug/"));
   Target target(setup.settings(), Label(SourceDir("//foo/"), "bar"));
 
-  target.script_values().set_depfile(
+  target.action_values().set_depfile(
       SourceFile("//out/Debug/gen/{{source_name_part}}.d"));
-  target.script_values().outputs().push_back(
+  target.action_values().outputs().push_back(
       SourceFile("//out/Debug/gen/{{source_name_part}}.h"));
-  target.script_values().outputs().push_back(
+  target.action_values().outputs().push_back(
       SourceFile("//out/Debug/gen/{{source_name_part}}.cc"));
 
   std::ostringstream out;
-  NinjaScriptTargetWriter writer(&target, setup.toolchain(), out);
+  NinjaActionTargetWriter writer(&target, setup.toolchain(), out);
 
   FileTemplate output_template = writer.GetOutputTemplate();
 
@@ -64,13 +64,13 @@ TEST(NinjaScriptTargetWriter, WriteOutputFilesForBuildLineWithDepfile) {
   EXPECT_EQ(" gen/bar.d gen/bar.h gen/bar.cc", out_str);
 }
 
-TEST(NinjaScriptTargetWriter, WriteArgsSubstitutions) {
+TEST(NinjaActionTargetWriter, WriteArgsSubstitutions) {
   TestWithScope setup;
   setup.build_settings()->SetBuildDir(SourceDir("//out/Debug/"));
   Target target(setup.settings(), Label(SourceDir("//foo/"), "bar"));
 
   std::ostringstream out;
-  NinjaScriptTargetWriter writer(&target, setup.toolchain(), out);
+  NinjaActionTargetWriter writer(&target, setup.toolchain(), out);
 
   std::vector<std::string> args;
   args.push_back("-i");
@@ -88,24 +88,100 @@ TEST(NinjaScriptTargetWriter, WriteArgsSubstitutions) {
             out_str);
 }
 
-// Tests the "run script over multiple source files" mode.
-TEST(NinjaScriptTargetWriter, InvokeOverSources) {
+// Makes sure that we write sources as input dependencies for actions with
+// both sources and source_prereqs (ACTION_FOREACH treats the sources
+// differently).
+TEST(NinjaActionTargetWriter, ActionWithSources) {
   TestWithScope setup;
   setup.build_settings()->SetBuildDir(SourceDir("//out/Debug/"));
   Target target(setup.settings(), Label(SourceDir("//foo/"), "bar"));
-  target.set_output_type(Target::CUSTOM);
+  target.set_output_type(Target::ACTION);
+
+  target.action_values().set_script(SourceFile("//foo/script.py"));
+
+  target.sources().push_back(SourceFile("//foo/source.txt"));
+  target.source_prereqs().push_back(SourceFile("//foo/included.txt"));
+
+  target.action_values().outputs().push_back(
+      SourceFile("//out/Debug/foo.out"));
+
+  // Posix.
+  {
+    setup.settings()->set_target_os(Settings::LINUX);
+    setup.build_settings()->set_python_path(base::FilePath(FILE_PATH_LITERAL(
+        "/usr/bin/python")));
+
+    std::ostringstream out;
+    NinjaActionTargetWriter writer(&target, setup.toolchain(), out);
+    writer.Run();
+
+    const char expected_linux[] =
+        "rule __foo_bar___rule\n"
+        "  command = /usr/bin/python ../../foo/script.py\n"
+        "  description = ACTION //foo:bar()\n"
+        "  restat = 1"
+        "\n"
+        "\n"
+        "build foo.out: __foo_bar___rule | ../../foo/included.txt ../../foo/source.txt\n"
+        "\n"
+        "build obj/foo/bar.stamp: stamp foo.out\n";
+    std::string out_str = out.str();
+#if defined(OS_WIN)
+    std::replace(out_str.begin(), out_str.end(), '\\', '/');
+#endif
+    EXPECT_EQ(expected_linux, out_str);
+  }
+
+  // Windows.
+  {
+    // Note: we use forward slashes here so that the output will be the same on
+    // Linux and Windows.
+    setup.build_settings()->set_python_path(base::FilePath(FILE_PATH_LITERAL(
+        "C:/python/python.exe")));
+    setup.settings()->set_target_os(Settings::WIN);
+
+    std::ostringstream out;
+    NinjaActionTargetWriter writer(&target, setup.toolchain(), out);
+    writer.Run();
+
+    // TODO(brettw) I think we'll need to worry about backslashes here
+    // depending if we're on actual Windows or Linux pretending to be Windows.
+    const char expected_win[] =
+        "rule __foo_bar___rule\n"
+        "  command = C:/python/python.exe gyp-win-tool action-wrapper environment.x86 __foo_bar___rule.$unique_name.rsp\n"
+        "  description = ACTION //foo:bar()\n"
+        "  restat = 1\n"
+        "  rspfile = __foo_bar___rule.$unique_name.rsp\n"
+        "  rspfile_content = C:/python/python.exe ../../foo/script.py\n"
+        "\n"
+        "build foo.out: __foo_bar___rule | ../../foo/included.txt ../../foo/source.txt\n"
+        "\n"
+        "build obj/foo/bar.stamp: stamp foo.out\n";
+    std::string out_str = out.str();
+#if defined(OS_WIN)
+    std::replace(out_str.begin(), out_str.end(), '\\', '/');
+#endif
+    EXPECT_EQ(expected_win, out_str);
+  }
+}
+
+TEST(NinjaActionTargetWriter, ForEach) {
+  TestWithScope setup;
+  setup.build_settings()->SetBuildDir(SourceDir("//out/Debug/"));
+  Target target(setup.settings(), Label(SourceDir("//foo/"), "bar"));
+  target.set_output_type(Target::ACTION_FOREACH);
 
   target.sources().push_back(SourceFile("//foo/input1.txt"));
   target.sources().push_back(SourceFile("//foo/input2.txt"));
 
-  target.script_values().set_script(SourceFile("//foo/script.py"));
+  target.action_values().set_script(SourceFile("//foo/script.py"));
 
-  target.script_values().args().push_back("-i");
-  target.script_values().args().push_back("{{source}}");
-  target.script_values().args().push_back(
+  target.action_values().args().push_back("-i");
+  target.action_values().args().push_back("{{source}}");
+  target.action_values().args().push_back(
       "--out=foo bar{{source_name_part}}.o");
 
-  target.script_values().outputs().push_back(
+  target.action_values().outputs().push_back(
       SourceFile("//out/Debug/{{source_name_part}}.out"));
 
   target.source_prereqs().push_back(SourceFile("//foo/included.txt"));
@@ -117,14 +193,14 @@ TEST(NinjaScriptTargetWriter, InvokeOverSources) {
         "/usr/bin/python")));
 
     std::ostringstream out;
-    NinjaScriptTargetWriter writer(&target, setup.toolchain(), out);
+    NinjaActionTargetWriter writer(&target, setup.toolchain(), out);
     writer.Run();
 
     const char expected_linux[] =
         "rule __foo_bar___rule\n"
         "  command = /usr/bin/python ../../foo/script.py -i ${source} "
             "\"--out=foo$ bar${source_name_part}.o\"\n"
-        "  description = CUSTOM //foo:bar()\n"
+        "  description = ACTION //foo:bar()\n"
         "  restat = 1\n"
         "\n"
         "build input1.out: __foo_bar___rule ../../foo/input1.txt | "
@@ -154,7 +230,7 @@ TEST(NinjaScriptTargetWriter, InvokeOverSources) {
     setup.settings()->set_target_os(Settings::WIN);
 
     std::ostringstream out;
-    NinjaScriptTargetWriter writer(&target, setup.toolchain(), out);
+    NinjaActionTargetWriter writer(&target, setup.toolchain(), out);
     writer.Run();
 
     // TODO(brettw) I think we'll need to worry about backslashes here
@@ -163,7 +239,7 @@ TEST(NinjaScriptTargetWriter, InvokeOverSources) {
         "rule __foo_bar___rule\n"
         "  command = C:/python/python.exe gyp-win-tool action-wrapper "
             "environment.x86 __foo_bar___rule.$unique_name.rsp\n"
-        "  description = CUSTOM //foo:bar()\n"
+        "  description = ACTION //foo:bar()\n"
         "  restat = 1\n"
         "  rspfile = __foo_bar___rule.$unique_name.rsp\n"
         "  rspfile_content = C:/python/python.exe ../../foo/script.py -i "
@@ -189,26 +265,25 @@ TEST(NinjaScriptTargetWriter, InvokeOverSources) {
   }
 }
 
-// Tests the "run script over multiple source files" mode, with a depfile.
-TEST(NinjaScriptTargetWriter, InvokeOverSourcesWithDepfile) {
+TEST(NinjaActionTargetWriter, ForEachWithDepfile) {
   TestWithScope setup;
   setup.build_settings()->SetBuildDir(SourceDir("//out/Debug/"));
   Target target(setup.settings(), Label(SourceDir("//foo/"), "bar"));
-  target.set_output_type(Target::CUSTOM);
+  target.set_output_type(Target::ACTION_FOREACH);
 
   target.sources().push_back(SourceFile("//foo/input1.txt"));
   target.sources().push_back(SourceFile("//foo/input2.txt"));
 
-  target.script_values().set_script(SourceFile("//foo/script.py"));
-  target.script_values().set_depfile(
+  target.action_values().set_script(SourceFile("//foo/script.py"));
+  target.action_values().set_depfile(
       SourceFile("//out/Debug/gen/{{source_name_part}}.d"));
 
-  target.script_values().args().push_back("-i");
-  target.script_values().args().push_back("{{source}}");
-  target.script_values().args().push_back(
+  target.action_values().args().push_back("-i");
+  target.action_values().args().push_back("{{source}}");
+  target.action_values().args().push_back(
       "--out=foo bar{{source_name_part}}.o");
 
-  target.script_values().outputs().push_back(
+  target.action_values().outputs().push_back(
       SourceFile("//out/Debug/{{source_name_part}}.out"));
 
   target.source_prereqs().push_back(SourceFile("//foo/included.txt"));
@@ -220,14 +295,14 @@ TEST(NinjaScriptTargetWriter, InvokeOverSourcesWithDepfile) {
         "/usr/bin/python")));
 
     std::ostringstream out;
-    NinjaScriptTargetWriter writer(&target, setup.toolchain(), out);
+    NinjaActionTargetWriter writer(&target, setup.toolchain(), out);
     writer.Run();
 
     const char expected_linux[] =
         "rule __foo_bar___rule\n"
         "  command = /usr/bin/python ../../foo/script.py -i ${source} "
             "\"--out=foo$ bar${source_name_part}.o\"\n"
-        "  description = CUSTOM //foo:bar()\n"
+        "  description = ACTION //foo:bar()\n"
         "  restat = 1\n"
         "\n"
         "build gen/input1.d input1.out: __foo_bar___rule ../../foo/input1.txt"
@@ -259,7 +334,7 @@ TEST(NinjaScriptTargetWriter, InvokeOverSourcesWithDepfile) {
     setup.settings()->set_target_os(Settings::WIN);
 
     std::ostringstream out;
-    NinjaScriptTargetWriter writer(&target, setup.toolchain(), out);
+    NinjaActionTargetWriter writer(&target, setup.toolchain(), out);
     writer.Run();
 
     // TODO(brettw) I think we'll need to worry about backslashes here
@@ -268,7 +343,7 @@ TEST(NinjaScriptTargetWriter, InvokeOverSourcesWithDepfile) {
         "rule __foo_bar___rule\n"
         "  command = C:/python/python.exe gyp-win-tool action-wrapper "
             "environment.x86 __foo_bar___rule.$unique_name.rsp\n"
-        "  description = CUSTOM //foo:bar()\n"
+        "  description = ACTION //foo:bar()\n"
         "  restat = 1\n"
         "  rspfile = __foo_bar___rule.$unique_name.rsp\n"
         "  rspfile_content = C:/python/python.exe ../../foo/script.py -i "
diff --git a/tools/gn/ninja_copy_target_writer.cc b/tools/gn/ninja_copy_target_writer.cc
index 89b3e3f..9ab88e4 100644
--- a/tools/gn/ninja_copy_target_writer.cc
+++ b/tools/gn/ninja_copy_target_writer.cc
@@ -18,7 +18,7 @@ NinjaCopyTargetWriter::~NinjaCopyTargetWriter() {
 }
 
 void NinjaCopyTargetWriter::Run() {
-  CHECK(target_->script_values().outputs().size() == 1);
+  CHECK(target_->action_values().outputs().size() == 1);
   FileTemplate output_template(GetOutputTemplate());
 
   std::vector<OutputFile> output_files;
diff --git a/tools/gn/ninja_copy_target_writer_unittest.cc b/tools/gn/ninja_copy_target_writer_unittest.cc
index 5642d9d..b86508b 100644
--- a/tools/gn/ninja_copy_target_writer_unittest.cc
+++ b/tools/gn/ninja_copy_target_writer_unittest.cc
@@ -19,7 +19,7 @@ TEST(NinjaCopyTargetWriter, Run) {
   target.sources().push_back(SourceFile("//foo/input1.txt"));
   target.sources().push_back(SourceFile("//foo/input2.txt"));
 
-  target.script_values().outputs().push_back(
+  target.action_values().outputs().push_back(
       SourceFile("//out/Debug/{{source_name_part}}.out"));
 
   // Posix.
diff --git a/tools/gn/ninja_helper.cc b/tools/gn/ninja_helper.cc
index eddab213..849ec4d 100644
--- a/tools/gn/ninja_helper.cc
+++ b/tools/gn/ninja_helper.cc
@@ -135,7 +135,8 @@ OutputFile NinjaHelper::GetTargetOutputFile(const Target* target) const {
     if (target->output_type() == Target::GROUP ||
         target->output_type() == Target::SOURCE_SET ||
         target->output_type() == Target::COPY_FILES ||
-        target->output_type() == Target::CUSTOM) {
+        target->output_type() == Target::ACTION ||
+        target->output_type() == Target::ACTION_FOREACH) {
       extension = "stamp";
     } else {
       extension = GetExtensionForOutputType(target->output_type(),
diff --git a/tools/gn/ninja_target_writer.cc b/tools/gn/ninja_target_writer.cc
index adb1108..905f91f 100644
--- a/tools/gn/ninja_target_writer.cc
+++ b/tools/gn/ninja_target_writer.cc
@@ -10,10 +10,10 @@
 #include "base/file_util.h"
 #include "tools/gn/err.h"
 #include "tools/gn/file_template.h"
+#include "tools/gn/ninja_action_target_writer.h"
 #include "tools/gn/ninja_binary_target_writer.h"
 #include "tools/gn/ninja_copy_target_writer.h"
 #include "tools/gn/ninja_group_target_writer.h"
-#include "tools/gn/ninja_script_target_writer.h"
 #include "tools/gn/scheduler.h"
 #include "tools/gn/string_utils.h"
 #include "tools/gn/target.h"
@@ -61,8 +61,9 @@ void NinjaTargetWriter::RunAndWriteFile(const Target* target,
   if (target->output_type() == Target::COPY_FILES) {
     NinjaCopyTargetWriter writer(target, toolchain, file);
     writer.Run();
-  } else if (target->output_type() == Target::CUSTOM) {
-    NinjaScriptTargetWriter writer(target, toolchain, file);
+  } else if (target->output_type() == Target::ACTION ||
+             target->output_type() == Target::ACTION_FOREACH) {
+    NinjaActionTargetWriter writer(target, toolchain, file);
     writer.Run();
   } else if (target->output_type() == Target::GROUP) {
     NinjaGroupTargetWriter writer(target, toolchain, file);
@@ -110,7 +111,7 @@ std::string NinjaTargetWriter::GetSourcesImplicitDeps() const {
 }
 
 FileTemplate NinjaTargetWriter::GetOutputTemplate() const {
-  const Target::FileList& outputs = target_->script_values().outputs();
+  const Target::FileList& outputs = target_->action_values().outputs();
   std::vector<std::string> output_template_args;
   for (size_t i = 0; i < outputs.size(); i++) {
     // All outputs should be in the output dir.
diff --git a/tools/gn/script_target_generator.cc b/tools/gn/script_target_generator.cc
deleted file mode 100644
index 8f414f4..0000000
--- a/tools/gn/script_target_generator.cc
+++ /dev/null
@@ -1,95 +0,0 @@
-// Copyright (c) 2013 The Chromium Authors. All rights reserved.
-// Use of this source code is governed by a BSD-style license that can be
-// found in the LICENSE file.
-
-#include "tools/gn/script_target_generator.h"
-
-#include "tools/gn/build_settings.h"
-#include "tools/gn/err.h"
-#include "tools/gn/filesystem_utils.h"
-#include "tools/gn/parse_tree.h"
-#include "tools/gn/scope.h"
-#include "tools/gn/value.h"
-#include "tools/gn/value_extractors.h"
-#include "tools/gn/variables.h"
-
-ScriptTargetGenerator::ScriptTargetGenerator(
-    Target* target,
-    Scope* scope,
-    const FunctionCallNode* function_call,
-    Err* err)
-    : TargetGenerator(target, scope, function_call, err) {
-}
-
-ScriptTargetGenerator::~ScriptTargetGenerator() {
-}
-
-void ScriptTargetGenerator::DoRun() {
-  target_->set_output_type(Target::CUSTOM);
-
-  FillExternal();
-  if (err_->has_error())
-    return;
-
-  FillSources();
-  if (err_->has_error())
-    return;
-
-  FillSourcePrereqs();
-  if (err_->has_error())
-    return;
-
-  FillScript();
-  if (err_->has_error())
-    return;
-
-  FillScriptArgs();
-  if (err_->has_error())
-    return;
-
-  FillOutputs();
-  if (err_->has_error())
-    return;
-
-  FillDepfile();
-  if (err_->has_error())
-    return;
-
-  // Script outputs don't depend on the current toolchain so we can skip adding
-  // that dependency.
-}
-
-void ScriptTargetGenerator::FillScript() {
-  // If this gets called, the target type requires a script, so error out
-  // if it doesn't have one.
-  const Value* value = scope_->GetValue(variables::kScript, true);
-  if (!value) {
-    *err_ = Err(function_call_, "This target type requires a \"script\".");
-    return;
-  }
-  if (!value->VerifyTypeIs(Value::STRING, err_))
-    return;
-
-  target_->script_values().set_script(
-      scope_->GetSourceDir().ResolveRelativeFile(value->string_value()));
-}
-
-void ScriptTargetGenerator::FillScriptArgs() {
-  const Value* value = scope_->GetValue(variables::kArgs, true);
-  if (!value)
-    return;
-
-  std::vector<std::string> args;
-  if (!ExtractListOfStringValues(*value, &args, err_))
-    return;
-  target_->script_values().swap_in_args(&args);
-}
-
-void ScriptTargetGenerator::FillDepfile() {
-  const Value* value = scope_->GetValue(variables::kDepfile, true);
-  if (!value)
-    return;
-  target_->script_values().set_depfile(
-      scope_->settings()->build_settings()->build_dir().ResolveRelativeFile(
-          value->string_value()));
-}
diff --git a/tools/gn/script_target_generator.h b/tools/gn/script_target_generator.h
deleted file mode 100644
index 4d79e51..0000000
--- a/tools/gn/script_target_generator.h
+++ /dev/null
@@ -1,31 +0,0 @@
-// Copyright (c) 2013 The Chromium Authors. All rights reserved.
-// Use of this source code is governed by a BSD-style license that can be
-// found in the LICENSE file.
-
-#ifndef TOOLS_GN_SCRIPT_TARGET_GENERATOR_H_
-#define TOOLS_GN_SCRIPT_TARGET_GENERATOR_H_
-
-#include "base/compiler_specific.h"
-#include "tools/gn/target_generator.h"
-
-// Populates a Target with the values from a custom script rule.
-class ScriptTargetGenerator : public TargetGenerator {
- public:
-  ScriptTargetGenerator(Target* target,
-                        Scope* scope,
-                        const FunctionCallNode* function_call,
-                        Err* err);
-  virtual ~ScriptTargetGenerator();
-
- protected:
-  virtual void DoRun() OVERRIDE;
-
- private:
-  void FillScript();
-  void FillScriptArgs();
-  void FillDepfile();
-
-  DISALLOW_COPY_AND_ASSIGN(ScriptTargetGenerator);
-};
-
-#endif  // TOOLS_GN_SCRIPT_TARGET_GENERATOR_H_
diff --git a/tools/gn/target.cc b/tools/gn/target.cc
index 635c50e..56b140f 100644
--- a/tools/gn/target.cc
+++ b/tools/gn/target.cc
@@ -76,8 +76,10 @@ const char* Target::GetStringForOutputType(OutputType type) {
       return "Static library";
     case COPY_FILES:
       return "Copy";
-    case CUSTOM:
-      return "Custom";
+    case ACTION:
+      return "Action";
+    case ACTION_FOREACH:
+      return "ActionForEach";
     default:
       return "";
   }
diff --git a/tools/gn/target.h b/tools/gn/target.h
index 4501494..2cf0409 100644
--- a/tools/gn/target.h
+++ b/tools/gn/target.h
@@ -14,11 +14,11 @@
 #include "base/logging.h"
 #include "base/strings/string_piece.h"
 #include "base/synchronization/lock.h"
+#include "tools/gn/action_values.h"
 #include "tools/gn/config_values.h"
 #include "tools/gn/item.h"
 #include "tools/gn/label_ptr.h"
 #include "tools/gn/ordered_set.h"
-#include "tools/gn/script_values.h"
 #include "tools/gn/source_file.h"
 
 class InputFile;
@@ -35,7 +35,8 @@ class Target : public Item {
     STATIC_LIBRARY,
     SOURCE_SET,
     COPY_FILES,
-    CUSTOM,
+    ACTION,
+    ACTION_FOREACH,
   };
   typedef std::vector<SourceFile> FileList;
   typedef std::vector<std::string> StringVector;
@@ -131,8 +132,8 @@ class Target : public Item {
   ConfigValues& config_values() { return config_values_; }
   const ConfigValues& config_values() const { return config_values_; }
 
-  ScriptValues& script_values() { return script_values_; }
-  const ScriptValues& script_values() const { return script_values_; }
+  ActionValues& action_values() { return action_values_; }
+  const ActionValues& action_values() const { return action_values_; }
 
   const OrderedSet<SourceDir>& all_lib_dirs() const { return all_lib_dirs_; }
   const OrderedSet<std::string>& all_libs() const { return all_libs_; }
@@ -187,7 +188,7 @@ class Target : public Item {
   OrderedSet<std::string> all_libs_;
 
   ConfigValues config_values_;  // Used for all binary targets.
-  ScriptValues script_values_;  // Used for script (CUSTOM) targets.
+  ActionValues action_values_;  // Used for action[_foreach] targets.
 
   SourceFile gyp_file_;
 
diff --git a/tools/gn/target_generator.cc b/tools/gn/target_generator.cc
index 81c4394..2fb178a 100644
--- a/tools/gn/target_generator.cc
+++ b/tools/gn/target_generator.cc
@@ -4,6 +4,7 @@
 
 #include "tools/gn/target_generator.h"
 
+#include "tools/gn/action_target_generator.h"
 #include "tools/gn/binary_target_generator.h"
 #include "tools/gn/build_settings.h"
 #include "tools/gn/config.h"
@@ -15,7 +16,6 @@
 #include "tools/gn/parse_tree.h"
 #include "tools/gn/scheduler.h"
 #include "tools/gn/scope.h"
-#include "tools/gn/script_target_generator.h"
 #include "tools/gn/token.h"
 #include "tools/gn/value.h"
 #include "tools/gn/value_extractors.h"
@@ -75,8 +75,13 @@ void TargetGenerator::GenerateTarget(Scope* scope,
   if (output_type == functions::kCopy) {
     CopyTargetGenerator generator(target.get(), scope, function_call, err);
     generator.Run();
-  } else if (output_type == functions::kCustom) {
-    ScriptTargetGenerator generator(target.get(), scope, function_call, err);
+  } else if (output_type == functions::kAction) {
+    ActionTargetGenerator generator(target.get(), scope, function_call,
+                                    Target::ACTION, err);
+    generator.Run();
+  } else if (output_type == functions::kActionForEach) {
+    ActionTargetGenerator generator(target.get(), scope, function_call,
+                                    Target::ACTION_FOREACH, err);
     generator.Run();
   } else if (output_type == functions::kExecutable) {
     BinaryTargetGenerator generator(target.get(), scope, function_call,
@@ -215,7 +220,7 @@ void TargetGenerator::FillOutputs() {
             outputs[i].value(), value->list_value()[i], err_))
       return;
   }
-  target_->script_values().outputs().swap(outputs);
+  target_->action_values().outputs().swap(outputs);
 }
 
 void TargetGenerator::FillGenericConfigs(const char* var_name,
diff --git a/tools/gn/variables.cc b/tools/gn/variables.cc
index b05e818..8fac840 100644
--- a/tools/gn/variables.cc
+++ b/tools/gn/variables.cc
@@ -181,7 +181,7 @@ const char kRootOutDir_Help[] =
     "\n"
     "Example:\n"
     "\n"
-    "  custom(\"myscript\") {\n"
+    "  action(\"myscript\") {\n"
     "    # Pass the output dir to the script.\n"
     "    args = [ \"-o\", rebase_path(root_out_dir, root_build_dir) ]\n"
     "  }\n";
@@ -206,7 +206,7 @@ const char kTargetGenDir_Help[] =
     "\n"
     "Example:\n"
     "\n"
-    "  custom(\"myscript\") {\n"
+    "  action(\"myscript\") {\n"
     "    # Pass the generated output dir to the script.\n"
     "    args = [ \"-o\", rebase_path(target_gen_dir, root_build_dir) ]"
     "\n"
@@ -232,7 +232,7 @@ const char kTargetOutDir_Help[] =
     "\n"
     "Example:\n"
     "\n"
-    "  custom(\"myscript\") {\n"
+    "  action(\"myscript\") {\n"
     "    # Pass the output dir to the script.\n"
     "    args = [ \"-o\", rebase_path(target_out_dir, root_build_dir) ]"
     "\n"
@@ -263,15 +263,15 @@ const char kAllDependentConfigs_Help[] =
 
 const char kArgs[] = "args";
 const char kArgs_HelpShort[] =
-    "args: [string list] Arguments passed to a custom script.";
+    "args: [string list] Arguments passed to an action.";
 const char kArgs_Help[] =
-    "args: Arguments passed to a custom script.\n"
+    "args: Arguments passed to an action.\n"
     "\n"
-    "  For custom script targets, args is the list of arguments to pass\n"
-    "  to the script. Typically you would use source expansion (see\n"
+    "  For action and action_foreach targets, args is the list of arguments\n"
+    "  to pass to the script. Typically you would use source expansion (see\n"
     "  \"gn help source_expansion\") to insert the source file names.\n"
     "\n"
-    "  See also \"gn help custom\".\n";
+    "  See also \"gn help action\" and \"gn help action_foreach\".\n";
 
 const char kCflags[] = "cflags";
 const char kCflags_HelpShort[] =
@@ -398,25 +398,25 @@ const char kDefines_Help[] =
 
 const char kDepfile[] = "depfile";
 const char kDepfile_HelpShort[] =
-    "depfile: [string] File name for input dependencies for custom targets.";
+    "depfile: [string] File name for input dependencies for actions.";
 const char kDepfile_Help[] =
-    "depfile: [string] File name for input dependencies for custom targets.\n"
+    "depfile: [string] File name for input dependencies for actions.\n"
     "\n"
-    "  If nonempty, this string specifies that the current \"custom\" target\n"
-    "  will generate the given \".d\" file containing the dependencies of the\n"
-    "  input. Empty or unset means that the script doesn't generate the\n"
-    "  files.\n"
+    "  If nonempty, this string specifies that the current action or\n"
+    "  action_foreach target will generate the given \".d\" file containing\n"
+    "  the dependencies of the input. Empty or unset means that the script\n"
+    "  doesn't generate the files.\n"
     "\n"
     "  The .d file should go in the target output directory. If you have more\n"
     "  than one source file that the script is being run over, you can use\n"
-    "  the output file expansions described in \"gn help custom\" to name the\n"
-    "  .d file according to the input."
+    "  the output file expansions described in \"gn help action_foreach\" to\n"
+    "  name the .d file according to the input."
     "\n"
     "  The format is that of a Makefile, and all of the paths should be\n"
     "  relative to the root build directory.\n"
     "\n"
     "Example:\n"
-    "  custom(\"myscript_target\") {\n"
+    "  action_foreach(\"myscript_target\") {\n"
     "    script = \"myscript.py\"\n"
     "    sources = [ ... ]\n"
     "\n"
@@ -438,9 +438,9 @@ const char kDeps_Help[] =
     "\n"
     "  Specifies dependencies of a target. Shared and dynamic libraries will\n"
     "  be linked into the current target. Other target types that can't be\n"
-    "  linked (like custom scripts and groups) listed in \"deps\" will be\n"
-    "  treated as \"datadeps\". Likewise, if the current target isn't\n"
-    "  linkable, then all deps will be treated as \"datadeps\".\n"
+    "  linked (like actions and groups) listed in \"deps\" will be treated\n"
+    "  as \"datadeps\". Likewise, if the current target isn't linkable, then\n"
+    "  all deps will be treated as \"datadeps\".\n"
     "\n"
     "  See also \"datadeps\".\n";
 
@@ -578,7 +578,7 @@ const char kHardDep_Help[] =
     "    ...\n"
     "  }\n"
     "\n"
-    "  custom(\"myresource\") {\n"
+    "  action(\"myresource\") {\n"
     "    hard_dep = true\n"
     "    script = \"my_generator.py\"\n"
     "    outputs = \"$target_gen_dir/myresource.h\"\n"
@@ -708,27 +708,28 @@ const char kOutputName_Help[] =
 
 const char kOutputs[] = "outputs";
 const char kOutputs_HelpShort[] =
-    "outputs: [file list] Output files for custom script and copy targets.";
+    "outputs: [file list] Output files for actions and copy targets.";
 const char kOutputs_Help[] =
-    "outputs: Output files for custom script and copy targets.\n"
+    "outputs: Output files for actions and copy targets.\n"
     "\n"
-    "  Outputs is valid for \"copy\" and \"custom\" target types and\n"
-    "  indicates the resulting files. The values may contain source\n"
-    "  expansions to generate the output names from the sources (see\n"
+    "  Outputs is valid for \"copy\", \"action\", and \"action_foreach\"\n"
+    "  target types and indicates the resulting files. The values may contain\n"
+    "  source expansions to generate the output names from the sources (see\n"
     "  \"gn help source_expansion\").\n"
     "\n"
     "  For copy targets, the outputs is the destination for the copied\n"
-    "  file(s). For custom script targets, the outputs should be the list of\n"
-    "  files generated by the script.\n";
+    "  file(s). For actions, the outputs should be the list of files\n"
+    "  generated by the script.\n";
 
 const char kScript[] = "script";
 const char kScript_HelpShort[] =
-    "script: [file name] Script file for custom script targets.";
+    "script: [file name] Script file for actions.";
 const char kScript_Help[] =
-    "script: Script file for custom script targets.\n"
+    "script: Script file for actions.\n"
     "\n"
     "  An absolute or buildfile-relative file name of a Python script to run\n"
-    "  for a custom script target (see \"gn help custom\").\n";
+    "  for a action and action_foreach targets (see \"gn help action\" and\n"
+    "  \"gn help action_foreach\").\n";
 
 const char kSourcePrereqs[] = "source_prereqs";
 const char kSourcePrereqs_HelpShort[] =
@@ -757,7 +758,7 @@ const char kSourcePrereqs_Help[] =
     "  the normal include file dependency management will handle them more\n"
     "  efficiently anyway.\n"
     "\n"
-    "  For custom script targets that don't generate \".d\" files, the\n"
+    "  For action targets that don't generate \".d\" files, the\n"
     "  \"source_prereqs\" section is how you can list known compile-time\n"
     "  dependencies your script may have.\n"
     "\n"
@@ -772,7 +773,7 @@ const char kSourcePrereqs_Help[] =
     "    source_prereqs = [ \"$root_gen_dir/something/generated_data.h\" ]\n"
     "  }\n"
     "\n"
-    "  custom(\"myscript\") {\n"
+    "  action(\"myscript\") {\n"
     "    script = \"domything.py\"\n"
     "    source_prereqs = [ \"input.data\" ]\n"
     "  }\n";