GN threading refactor

tools/gn/target_manager.h

-// 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.
-
-#ifndef TOOLS_GN_TARGET_MANAGER_H_
-#define TOOLS_GN_TARGET_MANAGER_H_
-
-#include <set>
-#include <vector>
-
-#include "base/basictypes.h"
-#include "base/containers/hash_tables.h"
-#include "base/synchronization/lock.h"
-#include "tools/gn/target.h"
-
-class BuildSettings;
-class Err;
-class ItemTree;
-class LocationRange;
-class ToolchainManager;
-class Value;
-
-// Manages all the targets in the system. This integrates with the ItemTree
-// to manage the target-specific rules and creation.
-//
-// This class is threadsafe.
-class TargetManager {
- public:
-  explicit TargetManager(const BuildSettings* settings);
-  ~TargetManager();
-
-  // Gets a reference to a named target. The given target name is created if
-  // it doesn't exist.
-  //
-  // The label should be fully specified in that it should include an
-  // explicit toolchain.
-  //
-  // |specified_from_here| should indicate the dependency or the target
-  // generator causing this access for error message generation.
-  //
-  // |dep_from| should be set when a target is getting a dep that it depends
-  // on. |dep_from| indicates the target that specified the dependency. It
-  // will be used to track outstanding dependencies so we can know when the
-  // target and all of its dependencies are complete. It should be null when
-  // getting a target for other reasons.
-  //
-  // On failure, |err| will be set.
-  //
-  // The returned pointer must not be dereferenced until it's generated, since
-  // it could be being generated on another thread.
-  Target* GetTarget(const Label& label,
-                    const LocationRange& specified_from_here,
-                    Target* dep_from,
-                    Err* err);
-
-  // Called by a target when it has been loaded from the .gin file. Its
-  // dependencies may or may not be resolved yet.
-  bool TargetGenerationComplete(const Label& label, Err* err);
-
-  // Returns a list of all targets.
-  void GetAllTargets(std::vector<const Target*>* all_targets) const;
-
- private:
-  const BuildSettings* build_settings_;
-
-  DISALLOW_COPY_AND_ASSIGN(TargetManager);
-};
-
-#endif  // TOOLS_GN_TARGET_MANAGER_H