Add GN template for generated extensions API targets.

extensions/generated_extensions_api.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.
+
+# Defines a static library corresponding to the output of schema compiler tools
+# over a set of extensions API schemas (IDL or JSON format.) The library target
+# has implicit hard dependencies on all schema files listed by the invoker and
+# is itself a hard dependency.
+#
+# Invocations of this template may use the following variables:
+#
+# sources [required] A list of schema files to be compiled.
+#
+# root_namespace [required] The namespace in which generated API code is to be
+#   wrapped. C++ namespace syntax is accepted for nested namespace
+#   (e.g. "foo::bar::api").
+#
+# impl_dir [required] The path containing C++ implementations of API functions.
+#   This path is used as the root path when looking for
+#   {schema}/{schema}_api.h headers during the API bundle generation phase.
+#   Such headers, if found, are automatically included by the generated code.
+#
+# uncompiled_sources [optional] A list of schema files which should not be
+#   compiled, but which should still be processed for API bundle generation.
+#
+# deps [optional] If any deps are specified they will be inherited by the
+#   static library target.
+#
+# The static libarary target also inherits the visibility and output_name
+# of its invoker.
+
+template("generated_extensions_api") {
+  assert(defined(invoker.sources),
+         "\"sources\" must be defined for the $target_name template.")
+  assert(defined(invoker.root_namespace),
+         "\"root_namespace\" must be defined for the $target_name template.")
+  assert(defined(invoker.impl_dir),
+         "\"impl_dir\" must be defined for the $target_name template.")
+
+  # Keep a copy of the target_name here since it will be trampled
+  # in nested targets.
+  target_visibility = ":$target_name"
+
+  generated_config_name = target_name + "_generated_config"
+  config(generated_config_name) {
+    include_dirs = [ target_gen_dir ]
+    visibility = target_visibility
+  }
+
+  schemas = invoker.sources
+  root_namespace = invoker.root_namespace
+  impl_dir = invoker.impl_dir
+  uncompiled_schemas = []
+  if (defined(invoker.uncompiled_sources)) {
+    uncompiled_schemas = invoker.uncompiled_sources
+  }
+
+  compiler_root = "//tools/json_schema_compiler"
+  compiler_script = "$compiler_root/compiler.py"
+  compiler_sources = [
+    "$compiler_root/cc_generator.py",
+    "$compiler_root/code.py",
+    "$compiler_root/compiler.py",
+    "$compiler_root/cpp_generator.py",
+    "$compiler_root/cpp_type_generator.py",
+    "$compiler_root/cpp_util.py",
+    "$compiler_root/h_generator.py",
+    "$compiler_root/idl_schema.py",
+    "$compiler_root/model.py",
+    "$compiler_root/util_cc_helper.py",
+  ]
+
+  # This list mirrors the outputs that will be generated by the following
+  # action_foreach. It's used by the static_library target.
+  compiled_schema_outputs = process_file_template(
+    schemas,
+    [ "$target_gen_dir/{{source_name_part}}.cc",
+      "$target_gen_dir/{{source_name_part}}.h",
+    ])
+
+  schema_generator_name = target_name + "_schema_generator"
+  action_foreach(schema_generator_name) {
+    script = compiler_script
+    hard_dep = true
+    source_prereqs = compiler_sources
+    sources = schemas
+    outputs = [
+      "$target_gen_dir/{{source_name_part}}.cc",
+      "$target_gen_dir/{{source_name_part}}.h",
+    ]
+    args = [
+      "{{source}}",
+      "--root=" + rebase_path("//", root_build_dir),
+      "--destdir=" + rebase_path(root_gen_dir, root_build_dir),
+      "--namespace=$root_namespace",
+      "--generator=cpp" ]
+    visibility = target_visibility
+  }
+
+  bundle_generator_name = target_name + "_bundle_generator"
+  bundle_outputs = [
+    "$target_gen_dir/generated_api.cc",
+    "$target_gen_dir/generated_api.h",
+    "$target_gen_dir/generated_schemas.cc",
+    "$target_gen_dir/generated_schemas.h",
+  ]
+  action(bundle_generator_name) {
+    script = compiler_script
+    hard_dep = true
+    source_prereqs = compiler_sources + schemas + uncompiled_schemas
+    outputs = bundle_outputs
+    args = [
+      "--root=" + rebase_path("//", root_build_dir),
+      "--destdir=" + rebase_path(root_gen_dir, root_build_dir),
+      "--namespace=$root_namespace",
+      "--generator=cpp-bundle",
+      "--impl-dir=" + rebase_path(impl_dir, "//"),
+    ] +
+      rebase_path(schemas, root_build_dir) +
+      rebase_path(uncompiled_schemas, root_build_dir)
+  }
+
+  source_set(target_name) {
+    hard_dep = true
+    sources = compiled_schema_outputs + bundle_outputs
+    deps = [
+      ":$schema_generator_name",
+      ":$bundle_generator_name",
+      "//tools/json_schema_compiler:generated_api_util",
+    ]
+
+    if (defined(invoker.deps)) {
+      deps += invoker.deps
+    }
+    direct_dependent_configs = [ ":$generated_config_name" ]
+
+    if (defined(invoker.visibility)) {
+      visibility = invoker.visibility
+    }
+    if (defined(invoker.output_name)) {
+      output_name = invoker.output_name
+    }
+  }
+}