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      1 // Copyright (c) 2013 The Chromium Authors. All rights reserved.
      2 // Use of this source code is governed by a BSD-style license that can be
      3 // found in the LICENSE file.
      4 
      5 #ifndef TOOLS_GN_SCHEDULER_H_
      6 #define TOOLS_GN_SCHEDULER_H_
      7 
      8 #include "base/atomic_ref_count.h"
      9 #include "base/basictypes.h"
     10 #include "base/files/file_path.h"
     11 #include "base/message_loop/message_loop.h"
     12 #include "base/run_loop.h"
     13 #include "base/synchronization/lock.h"
     14 #include "base/threading/sequenced_worker_pool.h"
     15 #include "tools/gn/input_file_manager.h"
     16 
     17 class Target;
     18 
     19 // Maintains the thread pool and error state.
     20 class Scheduler {
     21  public:
     22   Scheduler();
     23   ~Scheduler();
     24 
     25   bool Run();
     26 
     27   base::MessageLoop* main_loop() { return &main_loop_; }
     28   base::SequencedWorkerPool* pool() { return pool_.get(); }
     29 
     30   InputFileManager* input_file_manager() { return input_file_manager_.get(); }
     31 
     32   bool verbose_logging() const { return verbose_logging_; }
     33   void set_verbose_logging(bool v) { verbose_logging_ = v; }
     34 
     35   // TODO(brettw) data race on this access (benign?).
     36   bool is_failed() const { return is_failed_; }
     37 
     38   void Log(const std::string& verb, const std::string& msg);
     39   void FailWithError(const Err& err);
     40 
     41   void ScheduleWork(const base::Closure& work);
     42 
     43   void Shutdown();
     44 
     45   // Declares that the given file was read and affected the build output.
     46   //
     47   // TODO(brettw) this is global rather than per-BuildSettings. If we
     48   // start using >1 build settings, then we probably want this to take a
     49   // BuildSettings object so we know the depdency on a per-build basis.
     50   void AddGenDependency(const base::FilePath& file);
     51   std::vector<base::FilePath> GetGenDependencies() const;
     52 
     53   // We maintain a count of the things we need to do that works like a
     54   // refcount. When this reaches 0, the program exits.
     55   void IncrementWorkCount();
     56   void DecrementWorkCount();
     57 
     58  private:
     59   void LogOnMainThread(const std::string& verb, const std::string& msg);
     60   void FailWithErrorOnMainThread(const Err& err);
     61 
     62   void DoTargetFileWrite(const Target* target);
     63 
     64   void DoWork(const base::Closure& closure);
     65 
     66   void OnComplete();
     67 
     68   base::MessageLoop main_loop_;
     69   scoped_refptr<base::SequencedWorkerPool> pool_;
     70 
     71   scoped_refptr<InputFileManager> input_file_manager_;
     72 
     73   base::RunLoop runner_;
     74 
     75   bool verbose_logging_;
     76 
     77   base::AtomicRefCount work_count_;
     78 
     79   mutable base::Lock lock_;
     80   bool is_failed_;
     81 
     82   // Used to track whether the worker pool has been shutdown. This is necessary
     83   // to clean up after tests that make a scheduler but don't run the message
     84   // loop.
     85   bool has_been_shutdown_;
     86 
     87   // Additional input dependencies. Protected by the lock.
     88   std::vector<base::FilePath> gen_dependencies_;
     89 
     90   DISALLOW_COPY_AND_ASSIGN(Scheduler);
     91 };
     92 
     93 extern Scheduler* g_scheduler;
     94 
     95 #endif  // TOOLS_GN_SCHEDULER_H_
     96 
     97