Add initial prototype for the GN meta-buildsystem.

tools/gn/scope_per_file_provider.cc

Index: tools/gn/scope_per_file_provider.cc
diff --git a/tools/gn/scope_per_file_provider.cc b/tools/gn/scope_per_file_provider.cc
new file mode 100644
index 0000000000000000000000000000000000000000..1799d9e12b96060bc16b1ba950dbfe2e2a8a91c1
--- /dev/null
+++ b/tools/gn/scope_per_file_provider.cc
@@ -0,0 +1,186 @@
+// 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/scope_per_file_provider.h"
+
+#include "tools/gn/filesystem_utils.h"
+#include "tools/gn/settings.h"
+#include "tools/gn/source_file.h"
+#include "tools/gn/toolchain_manager.h"
+#include "tools/gn/value.h"
+
+const char* ScopePerFileProvider::kDefaultToolchain =
+    "default_toolchain";
+const char* ScopePerFileProvider::kPythonPath =
+    "python_path";
+const char* ScopePerFileProvider::kToolchain =
+    "toolchain";
+const char* ScopePerFileProvider::kRootOutputDirName =
+    "root_output_dir";
+const char* ScopePerFileProvider::kRootGenDirName =
+    "root_gen_dir";
+const char* ScopePerFileProvider::kTargetOutputDirName =
+    "target_output_dir";
+const char* ScopePerFileProvider::kTargetGenDirName =
+    "target_gen_dir";
+const char* ScopePerFileProvider::kRelativeRootOutputDirName =
+    "relative_root_output_dir";
+const char* ScopePerFileProvider::kRelativeRootGenDirName =
+    "relative_root_gen_dir";
+const char* ScopePerFileProvider::kRelativeTargetOutputDirName =
+    "relative_target_output_dir";
+const char* ScopePerFileProvider::kRelativeTargetGenDirName =
+    "relative_target_gen_dir";
+
+ScopePerFileProvider::ScopePerFileProvider(Scope* scope,
+                                           const SourceFile& source_file)
+    : ProgrammaticProvider(scope),
+      source_file_(source_file) {
+}
+
+ScopePerFileProvider::~ScopePerFileProvider() {
+}
+
+const Value* ScopePerFileProvider::GetProgrammaticValue(
+    const base::StringPiece& ident) {
+  if (ident == kDefaultToolchain)
+    return GetDefaultToolchain();
+  if (ident == kPythonPath)
+    return GetPythonPath();
+
+  if (ident == kTargetOutputDirName)
+    return GetTargetOutputDir();
+  if (ident == kTargetGenDirName)
+    return GetTargetGenDir();
+
+  if (ident == kRelativeRootOutputDirName)
+    return GetRelativeRootOutputDir();
+  if (ident == kRelativeRootGenDirName)
+    return GetRelativeRootGenDir();
+  if (ident == kRelativeTargetOutputDirName)
+    return GetRelativeTargetOutputDir();
+  if (ident == kRelativeTargetGenDirName)
+    return GetRelativeTargetGenDir();
+  return NULL;
+}
+
+// static
+Value ScopePerFileProvider::GetRootOutputDir(const Settings* settings) {
+  return Value(NULL, GetRootOutputDirWithNoLastSlash(settings));
+}
+
+// static
+Value ScopePerFileProvider::GetRootGenDir(const Settings* settings) {
+  return Value(NULL, GetRootGenDirWithNoLastSlash(settings));
+}
+
+const Value* ScopePerFileProvider::GetDefaultToolchain() {
+  if (!default_toolchain_) {
+    const ToolchainManager& toolchain_manager =
+        scope_->settings()->build_settings()->toolchain_manager();
+    default_toolchain_.reset(new Value(NULL,
+        toolchain_manager.GetDefaultToolchainUnlocked().GetUserVisibleName(
+            false)));
+  }
+  return default_toolchain_.get();
+}
+
+const Value* ScopePerFileProvider::GetPythonPath() {
+  if (!python_path_) {
+    python_path_.reset(new Value(NULL,
+        FilePathToUTF8(scope_->settings()->build_settings()->python_path())));
+  }
+  return python_path_.get();
+}
+
+const Value* ScopePerFileProvider::GetToolchain() {
+  if (!toolchain_) {
+    toolchain_.reset(new Value(NULL,
+        scope_->settings()->toolchain()->label().GetUserVisibleName(false)));
+  }
+  return toolchain_.get();
+}
+
+const Value* ScopePerFileProvider::GetTargetOutputDir() {
+  if (!target_output_dir_) {
+    target_output_dir_.reset(new Value(NULL,
+        GetRootOutputDirWithNoLastSlash(scope_->settings()) +
+        GetFileDirWithNoLastSlash()));
+  }
+  return target_output_dir_.get();
+}
+
+const Value* ScopePerFileProvider::GetTargetGenDir() {
+  if (!target_output_dir_) {
+    target_gen_dir_.reset(new Value(NULL,
+        GetRootGenDirWithNoLastSlash(scope_->settings()) +
+        GetFileDirWithNoLastSlash()));
+  }
+  return target_gen_dir_.get();
+}
+
+const Value* ScopePerFileProvider::GetRelativeRootOutputDir() {
+  if (!relative_root_output_dir_) {
+    relative_root_output_dir_.reset(new Value(NULL,
+        GetRelativeRootWithNoLastSlash() +
+        GetRootOutputDirWithNoLastSlash(scope_->settings())));
+  }
+  return relative_root_output_dir_.get();
+}
+
+const Value* ScopePerFileProvider::GetRelativeRootGenDir() {
+  if (!relative_root_gen_dir_) {
+    relative_root_gen_dir_.reset(new Value(NULL,
+        GetRelativeRootWithNoLastSlash() +
+        GetRootGenDirWithNoLastSlash(scope_->settings())));
+  }
+  return relative_root_gen_dir_.get();
+}
+
+const Value* ScopePerFileProvider::GetRelativeTargetOutputDir() {
+  if (!relative_target_output_dir_) {
+    relative_target_output_dir_.reset(new Value(NULL,
+        GetRelativeRootWithNoLastSlash() +
+        GetRootOutputDirWithNoLastSlash(scope_->settings()) + "obj/" +
+        GetFileDirWithNoLastSlash()));
+  }
+  return relative_target_output_dir_.get();
+}
+
+const Value* ScopePerFileProvider::GetRelativeTargetGenDir() {
+  if (!relative_target_gen_dir_) {
+    relative_target_gen_dir_.reset(new Value(NULL,
+        GetRelativeRootWithNoLastSlash() +
+        GetRootGenDirWithNoLastSlash(scope_->settings()) +
+        GetFileDirWithNoLastSlash()));
+  }
+  return relative_target_gen_dir_.get();
+}
+
+// static
+std::string ScopePerFileProvider::GetRootOutputDirWithNoLastSlash(
+    const Settings* settings) {
+  const std::string& output_dir =
+      settings->build_settings()->build_dir().value();
+  CHECK(!output_dir.empty());
+  return output_dir.substr(0, output_dir.size() - 1);
+}
+
+// static
+std::string ScopePerFileProvider::GetRootGenDirWithNoLastSlash(
+    const Settings* settings) {
+  return GetRootOutputDirWithNoLastSlash(settings) + "/gen";
+}
+
+std::string ScopePerFileProvider::GetFileDirWithNoLastSlash() const {
+  std::string dir_value = source_file_.GetDir().value();
+  return dir_value.substr(0, dir_value.size() - 1);
+}
+
+std::string ScopePerFileProvider::GetRelativeRootWithNoLastSlash() const {
+  std::string inverted = InvertDir(source_file_.GetDir());
+  if (inverted.empty())
+    return ".";
+  return inverted.substr(0, inverted.size() - 1);
+}