Add initial prototype for the GN meta-buildsystem.

tools/gn/config_values_generator.cc

Index: tools/gn/config_values_generator.cc
diff --git a/tools/gn/config_values_generator.cc b/tools/gn/config_values_generator.cc
new file mode 100644
index 0000000000000000000000000000000000000000..34c3f678f8093508e3e7aa9a16d1606f25fc8688
--- /dev/null
+++ b/tools/gn/config_values_generator.cc
@@ -0,0 +1,89 @@
+// 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/config_values_generator.h"
+
+#include "tools/gn/config_values.h"
+#include "tools/gn/scope.h"
+#include "tools/gn/value.h"
+#include "tools/gn/value_extractors.h"
+
+namespace {
+
+void GetStringList(
+    const Scope* scope,
+    const char* var_name,
+    ConfigValues* config_values,
+    void (ConfigValues::* swapper_inner)(std::vector<std::string>*),
+    Err* err) {
+  const Value* value = scope->GetValue(var_name);
+  if (!value)
+    return;  // No value, empty input and succeed.
+
+  std::vector<std::string> result;
+  ExtractListOfStringValues(*value, &result, err);
+  (config_values->*swapper_inner)(&result);
+}
+
+}  // namespace
+
+ConfigValuesGenerator::ConfigValuesGenerator(ConfigValues* dest_values,
+                                             const Scope* scope,
+                                             const Token& function_token,
+                                             const SourceDir& input_dir,
+                                             Err* err)
+    : config_values_(dest_values),
+      scope_(scope),
+      function_token_(function_token),
+      input_dir_(input_dir),
+      err_(err) {
+}
+
+ConfigValuesGenerator::~ConfigValuesGenerator() {
+}
+
+void ConfigValuesGenerator::Run() {
+  FillDefines();
+  FillIncludes();
+  FillCflags();
+  FillCflags_C();
+  FillCflags_CC();
+  FillLdflags();
+}
+
+void ConfigValuesGenerator::FillDefines() {
+  GetStringList(scope_, "defines", config_values_,
+                &ConfigValues::swap_in_defines, err_);
+}
+
+void ConfigValuesGenerator::FillIncludes() {
+  const Value* value = scope_->GetValue("includes");
+  if (!value)
+    return;  // No value, empty input and succeed.
+
+  std::vector<SourceDir> includes;
+  if (!ExtractListOfRelativeDirs(*value, input_dir_, &includes, err_))
+    return;
+  config_values_->swap_in_includes(&includes);
+}
+
+void ConfigValuesGenerator::FillCflags() {
+  GetStringList(scope_, "cflags", config_values_,
+                &ConfigValues::swap_in_cflags, err_);
+}
+
+void ConfigValuesGenerator::FillCflags_C() {
+  GetStringList(scope_, "cflags_c", config_values_,
+                &ConfigValues::swap_in_cflags_c, err_);
+}
+
+void ConfigValuesGenerator::FillCflags_CC() {
+  GetStringList(scope_, "cflags_cc", config_values_,
+                &ConfigValues::swap_in_cflags_cc, err_);
+}
+
+void ConfigValuesGenerator::FillLdflags() {
+  GetStringList(scope_, "ldflags", config_values_,
+                &ConfigValues::swap_in_ldflags, err_);
+}