Support script response files in GN.

tools/gn/functions_target.cc

 // 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/functions.h"
 
 #include "tools/gn/config_values_generator.h"
 #include "tools/gn/err.h"
 #include "tools/gn/parse_tree.h"
 #include "tools/gn/scope.h"
@@ skipping 90 matching lines @@
     "  handling. If you want to pass the sources to your script, you must do\n"
     "  so explicitly by including them in the \"args\". Note also that this\n"
     "  means there is no special handling of paths since GN doesn't know\n"
     "  which of the args are paths and not. You will want to use\n"
     "  rebase_path() to convert paths to be relative to the root_build_dir.\n"
     "\n"
     "  You can dynamically write input dependencies (for incremental rebuilds\n"
     "  if an input file changes) by writing a depfile when the script is run\n"
     "  (see \"gn help depfile\"). This is more flexible than \"inputs\".\n"
     "\n"
+    "  If the command line length is very long, you can use response files\n"
+    "  to pass args to your script. See \"gn help response_file_contents\".\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 \"inputs\" variable.\n"
     "\n"
     ACTION_DEPS
     "\n"
     "Outputs\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, console, data, data_deps, depfile, deps, outputs*, script*,\n"
-    "  inputs, sources\n"
+    "  args, console, data, data_deps, depfile, deps, inputs, outputs*,\n"
+    "  response_file_contents, script*, 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"
@@ skipping 33 matching lines @@
     "  \"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 \"inputs\" variable. These files are treated as\n"
     "  dependencies of each script invocation.\n"
     "\n"
+    "  If the command line length is very long, you can use response files\n"
+    "  to pass args to your script. See \"gn help response_file_contents\".\n"
+    "\n"
     "  You can dynamically write input dependencies (for incremental rebuilds\n"
     "  if an input file changes) by writing a depfile when the script is run\n"
     "  (see \"gn help depfile\"). This is more flexible than \"inputs\".\n"
     "\n"
     ACTION_DEPS
     "\n"
     "Outputs\n"
     "\n"
     SCRIPT_EXECUTION_CONTEXT
     "\n"
     "File name handling\n"
     "\n"
     SCRIPT_EXECUTION_OUTPUTS
     "\n"
     "Variables\n"
     "\n"
-    "  args, console, data, data_deps, depfile, deps, outputs*, script*,\n"
-    "  inputs, sources*\n"
+    "  args, console, data, data_deps, depfile, deps, inputs, outputs*,\n"
+    "  response_file_contents, script*, 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"
@@ skipping 338 matching lines @@
   const Template* templ = scope->GetTemplate(target_type);
   if (templ)
     return templ->Invoke(scope, function, sub_args, block, err);
 
   // Otherwise, assume the target is a built-in target type.
   return ExecuteGenericTarget(target_type.c_str(), scope, function, sub_args,
                               block, err);
 }
 
 }  // namespace functions