Revert 214254 "Add initial prototype for the GN meta-buildsystem."

trunk/src/tools/gn/import_manager.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/import_manager.h"
-
-#include "base/memory/scoped_ptr.h"
-#include "base/stl_util.h"
-#include "tools/gn/parse_tree.h"
-#include "tools/gn/scheduler.h"
-
-namespace {
-
-// Returns a newly-allocated scope on success, null on failure.
-Scope* UncachedImport(const Settings* settings,
-                      const SourceFile& file,
-                      const ParseNode* node_for_err,
-                      Err* err) {
-  const ParseNode* node = g_scheduler->input_file_manager()->SyncLoadFile(
-      node_for_err->GetRange(), settings->build_settings(), file, err);
-  if (!node)
-    return NULL;
-  const BlockNode* block = node->AsBlock();
-  CHECK(block);
-
-  scoped_ptr<Scope> scope(new Scope(settings->base_config()));
-  scope->SetProcessingImport();
-  block->ExecuteBlockInScope(scope.get(), err);
-  if (err->has_error())
-    return NULL;
-  scope->ClearProcessingImport();
-
-  return scope.release();
-}
-
-}  // namesapce
-
-ImportManager::ImportManager() {
-}
-
-ImportManager::~ImportManager() {
-  STLDeleteContainerPairSecondPointers(imports_.begin(), imports_.end());
-}
-
-bool ImportManager::DoImport(const SourceFile& file,
-                             const ParseNode* node_for_err,
-                             Scope* scope,
-                             Err* err) {
-  // See if we have a cached import, but be careful to actually do the scope
-  // copying outside of the lock.
-  const Scope* imported_scope = NULL;
-  {
-    base::AutoLock lock(lock_);
-    ImportMap::const_iterator found = imports_.find(file);
-    if (found != imports_.end())
-      imported_scope = found->second;
-  }
-
-  if (!imported_scope) {
-    // Do a new import of the file.
-    imported_scope = UncachedImport(scope->settings(), file,
-                                    node_for_err, err);
-    if (!imported_scope)
-      return false;
-
-    // We loaded the file outside the lock. This means that there could be a
-    // race and the file was already loaded on a background thread. Recover
-    // from this and use the existing one if that happens.
-    {
-      base::AutoLock lock(lock_);
-      ImportMap::const_iterator found = imports_.find(file);
-      if (found != imports_.end()) {
-        delete imported_scope;
-        imported_scope = found->second;
-      } else {
-        imports_[file] = imported_scope;
-      }
-    }
-  }
-
-  return imported_scope->NonRecursiveMergeTo(scope, node_for_err,
-                                             "import", err);
-}