tools/gn/scheduler.h

   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 <map>
   9
  10 #include "base/atomic_ref_count.h"
  11 #include "base/basictypes.h"
  12 #include "base/files/file_path.h"
  13 #include "base/message_loop/message_loop.h"
  14 #include "base/run_loop.h"
  15 #include "base/synchronization/lock.h"
  16 #include "base/threading/sequenced_worker_pool.h"
  17 #include "tools/gn/input_file_manager.h"
  18
  19 class Target;
  20
  21 // Maintains the thread pool and error state.
  22 class Scheduler {
  23  public:
  24   Scheduler();
  25   ~Scheduler();
  26
  27   bool Run();
  28
  29   base::MessageLoop* main_loop() { return &main_loop_; }
  30   base::SequencedWorkerPool* pool() { return pool_.get(); }
  31
  32   InputFileManager* input_file_manager() { return input_file_manager_.get(); }
  33
  34   bool verbose_logging() const { return verbose_logging_; }
  35   void set_verbose_logging(bool v) { verbose_logging_ = v; }
  36
  37   // TODO(brettw) data race on this access (benign?).
  38   bool is_failed() const { return is_failed_; }
  39
  40   void Log(const std::string& verb, const std::string& msg);
  41   void FailWithError(const Err& err);
  42
  43   void ScheduleWork(const base::Closure& work);
  44
  45   void Shutdown();
  46
  47   // Declares that the given file was read and affected the build output.
  48   //
  49   // TODO(brettw) this is global rather than per-BuildSettings. If we
  50   // start using >1 build settings, then we probably want this to take a
  51   // BuildSettings object so we know the depdency on a per-build basis.
  52   // If moved, most of the Add/Get functions below should move as well.
  53   void AddGenDependency(const base::FilePath& file);
  54   std::vector<base::FilePath> GetGenDependencies() const;
  55
  56   // Tracks calls to write_file for resolving with the unknown generated
  57   // inputs (see AddUnknownGeneratedInput below).
  58   void AddWrittenFile(const SourceFile& file);
  59
  60   // Unknown generated inputs are files that a target declares as an input
  61   // in the output directory, but which aren't generated by any dependency.
  62   //
  63   // Some of these files will be files written by write_file and will be
  64   // GenDependencies (see AddWrittenFile above). There are OK and include
  65   // things like response files for scripts. Others cases will be ones where
  66   // the file is generated by a target that's not a dependency.
  67   //
  68   // In order to distinguish these two cases, the checking for these input
  69   // files needs to be done after all targets are complete. This also has the
  70   // nice side effect that if a target generates the file we can find it and
  71   // tell the user which dependency is missing.
  72   //
  73   // The result returned by GetUnknownGeneratedInputs will not count any files
  74   // that were written by write_file during execution.
  75   void AddUnknownGeneratedInput(const Target* target, const SourceFile& file);
  76   std::multimap<SourceFile, const Target*> GetUnknownGeneratedInputs() const;
  77   void ClearUnknownGeneratedInputsAndWrittenFiles();  // For testing.
  78
  79   // We maintain a count of the things we need to do that works like a
  80   // refcount. When this reaches 0, the program exits.
  81   void IncrementWorkCount();
  82   void DecrementWorkCount();
  83
  84  private:
  85   void LogOnMainThread(const std::string& verb, const std::string& msg);
  86   void FailWithErrorOnMainThread(const Err& err);
  87
  88   void DoTargetFileWrite(const Target* target);
  89
  90   void DoWork(const base::Closure& closure);
  91
  92   void OnComplete();
  93
  94   base::MessageLoop main_loop_;
  95   scoped_refptr<base::SequencedWorkerPool> pool_;
  96
  97   scoped_refptr<InputFileManager> input_file_manager_;
  98
  99   base::RunLoop runner_;
 100
 101   bool verbose_logging_;
 102
 103   base::AtomicRefCount work_count_;
 104
 105   mutable base::Lock lock_;
 106   bool is_failed_;
 107
 108   // Used to track whether the worker pool has been shutdown. This is necessary
 109   // to clean up after tests that make a scheduler but don't run the message
 110   // loop.
 111   bool has_been_shutdown_;
 112
 113   // Protected by the lock. See the corresponding Add/Get functions above.
 114   std::vector<base::FilePath> gen_dependencies_;
 115   std::vector<SourceFile> written_files_;
 116   std::multimap<SourceFile, const Target*> unknown_generated_inputs_;
 117
 118   DISALLOW_COPY_AND_ASSIGN(Scheduler);
 119 };
 120
 121 extern Scheduler* g_scheduler;
 122
 123 #endif  // TOOLS_GN_SCHEDULER_H_
 124