gn: Generalize process_version() and move it to build/util

build/util/process_version.gni

 # Copyright 2014 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.
 
 import("//build/config/chrome_build.gni")
 
 # Runs the version processing script over the given template file to produce
 # an output file. This is used for generating various forms of files that
 # incorporate the product name and version.
 #
 # Unlike GYP, this will actually compile the resulting file, so you don't need
 # to add it separately to the sources, just depend on the target.
 #
-# This template automatically includes VERSION, LASTCHANGE, and BRANDING. It
-# automatically uses the template file .
-# GYP parameterizes this template file but all current invocations use this
-# same one. If in the future we need to set it, this should be added as an
-# optional argument.
-#
 # In GYP this is a rule that runs once per ".ver" file. In GN this just
 # processes one file per invocation of the template so you may have to have
 # multiple targets.
 #
 # Parameters:
 #   sources (optional):
 #     List of file names to read. When converting a GYP target, this should
 #     list the 'source' (see above) as well as any extra_variable_files.
+#     The files will be passed to version.py in the order specified here.
 #
 #   output:
 #     File name of file to write. In GYP this is unspecified and it will
 #     make up a file name for you based on the input name, and tack on
 #     "_version.rc" to the end. But in GN you need to specify the full name.
 #
 #   template_file (optional):
 #     Template file to use (not a list). Most Windows uses for generating
-#     resources will want to specify the chrome_version_rc_template defined
-#     below.
+#     resources will want to use process_version_rc_template() instead.
 #
 #   extra_args (optional):
 #     Extra arguments to pass to version.py. Any "-f <filename>" args should
 #     use sources instead.
 #
 #   process_only (optional, defaults to false)
 #     Set to generate only one action that processes the version file and
 #     doesn't attempt to link the result into a source set. This is for if
 #     you are processing the version as data only.
 #
 #   visibility (optional)
 #
 # Example:
 #   process_version("myversion") {
-#     sources = [ "myfile.h.in" ]
+#     sources = [
+#       "//chrome/VERSION"
+#       "myfile.h.in"
+#     ]
 #     output = "$target_gen_dir/myfile.h"
-#     extra_args = ["-e", "FOO=42"]
-#     extra_files = [ "foo/BRANDING" ]
+#     extra_args = [ "-e", "FOO=42" ]
 #   }
 template("process_version") {
   assert(defined(invoker.output), "Output must be defined for $target_name")
 
   process_only = defined(invoker.process_only) && invoker.process_only
 
   if (process_only) {
     action_name = target_name
   } else {
     action_name = target_name + "_action"
     source_set_name = target_name
   }
 
   action(action_name) {
     script = "//build/util/version.py"
 
-    lastchange_path = "//build/util/LASTCHANGE"
-    version_path = "//chrome/VERSION"
-    if (is_chrome_branded) {
-      branding_path = "//chrome/app/theme/google_chrome/BRANDING"
-    } else {
-      branding_path = "//chrome/app/theme/chromium/BRANDING"
-    }
-
-    inputs = [
-      version_path,
-      lastchange_path,
-      branding_path,
-    ]
+    inputs = []
     if (defined(invoker.inputs)) {
       inputs += invoker.inputs
     }
     if (defined(invoker.template_file)) {
       inputs += [ invoker.template_file ]
     }
 
     outputs = [
       invoker.output,
     ]
 
     args = []
 
     if (is_official_build) {
       args += [ "--official" ]
     }
 
     if (defined(invoker.sources)) {
       inputs += invoker.sources
       foreach(i, invoker.sources) {
         args += [
           "-f",
           rebase_path(i, root_build_dir),
         ]
       }
     }
 
-    args += [
-      "-f",
-      rebase_path(version_path, root_build_dir),
-      "-f",
-      rebase_path(branding_path, root_build_dir),
-      "-f",
-      rebase_path(lastchange_path, root_build_dir),
-    ]
     if (defined(invoker.extra_args)) {
       args += invoker.extra_args
     }
     args += [
       "-o",
       rebase_path(invoker.output, root_build_dir),
     ]
     if (defined(invoker.template_file)) {
       args += [ rebase_path(invoker.template_file, root_build_dir) ]
     }
@@ skipping 13 matching lines @@
     source_set(source_set_name) {
       forward_variables_from(invoker, [ "visibility" ])
       sources = get_target_outputs(":$action_name")
       public_deps = [
         ":$action_name",
       ]
     }
   }
 }
 
-chrome_version_rc_template = "//chrome/app/chrome_version.rc.version"
+# This is a wrapper around process_version() that eases the task of processing
+# a .rc.version file (used especially on Windows).
+#
+# This template automatically includes VERSION, LASTCHANGE and BRANDING, and
+# any additional source files are passed after those (so their values can
+# override the ones specified by those 3 files).
+#
+# Parameters:
+#   sources (optional):
+#     List of files with value definitions that will be passed in addition to
+#     VERSION, LASTCHANGE and BRANDING.
+#
+#   template_file (optional):
+#     Template file to use (not a list). If not specified, a default value,
+#     //chrome/app/chrome_version.rc.version will be used.
+#
+# This template forwards all other parameters directly to process_version().
+#
+# Examples:
+#   process_version_rc_template("my_exe_version") {
+#     output = "$target_gen_dir/my_exe_version.rc"
+#     sources = [ "frob/my_exe.ver" ]
+#     extra_args = [ "-e", "FOO=42" ]
+#   }
+#
+#   process_version_rc_template("my_dll_version") {
+#     output = "$target_gen_dir/my_dll_version.rc"
+#     template_file = [ "//foo/bar/my_dll_version.rc.version" ]
+#   }
+template("process_version_rc_template") {
+  if (defined(invoker.template_file)) {
+    _template_file = invoker.template_file
+  } else {
+    _template_file = "//chrome/app/chrome_version.rc.version"

[brettw, 2016/09/06 22:52:31]

Since this depends on files from //chrome, it should really be in the //chrome
directory. This was why the script used to be in //chrome with TODOs about
layering violations.

Your change allows these layering violations to be fixed (yay), we just need to
split apart the definitions so stuff in //build never references anything
outside of //build.

+  }
+  _sources = [
+    "//build/util/LASTCHANGE",
+    "//chrome/VERSION",
+    branding_file_path,
+  ]
+  if (defined(invoker.sources)) {
+    _sources += invoker.sources
+  }
+
+  process_version(target_name) {
+    template_file = _template_file
+    sources = _sources
+    forward_variables_from(invoker,
+                           "*",
+                           [
+                             "sources",
+                             "template_file",
+                           ])
+  }
+}