chrome/browser/sync_file_system/local/syncable_file_operation_runner.h

   1 // Copyright 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 CHROME_BROWSER_SYNC_FILE_SYSTEM_LOCAL_SYNCABLE_FILE_OPERATION_RUNNER_H_
   6 #define CHROME_BROWSER_SYNC_FILE_SYSTEM_LOCAL_SYNCABLE_FILE_OPERATION_RUNNER_H_
   7
   8 #include <list>
   9 #include <vector>
  10
  11 #include "base/basictypes.h"
  12 #include "base/callback.h"
  13 #include "base/memory/scoped_ptr.h"
  14 #include "base/memory/weak_ptr.h"
  15 #include "base/threading/non_thread_safe.h"
  16 #include "chrome/browser/sync_file_system/local/local_file_sync_status.h"
  17 #include "storage/browser/fileapi/file_system_url.h"
  18
  19 namespace storage {
  20 class FileSystemURL;
  21 }
  22
  23 namespace sync_file_system {
  24
  25 // This class must run only on IO thread.
  26 // Owned by LocalFileSyncContext.
  27 class SyncableFileOperationRunner
  28     : public base::NonThreadSafe,
  29       public base::SupportsWeakPtr<SyncableFileOperationRunner>,
  30       public LocalFileSyncStatus::Observer {
  31  public:
  32   // Represents an operation task (which usually wraps one FileSystemOperation).
  33   class Task {
  34    public:
  35     Task() {}
  36     virtual ~Task() {}
  37
  38     // Only one of Run() or Cancel() is called.
  39     virtual void Run() = 0;
  40     virtual void Cancel() = 0;
  41
  42    protected:
  43     // This is never called after Run() or Cancel() is called.
  44     virtual const std::vector<storage::FileSystemURL>& target_paths() const = 0;
  45
  46    private:
  47     friend class SyncableFileOperationRunner;
  48     bool IsRunnable(LocalFileSyncStatus* status) const;
  49     void Start(LocalFileSyncStatus* status);
  50     static void CancelAndDelete(Task* task);
  51
  52     DISALLOW_COPY_AND_ASSIGN(Task);
  53   };
  54
  55   SyncableFileOperationRunner(int64 max_inflight_tasks,
  56                               LocalFileSyncStatus* sync_status);
  57   ~SyncableFileOperationRunner() override;
  58
  59   // LocalFileSyncStatus::Observer overrides.
  60   void OnSyncEnabled(const storage::FileSystemURL& url) override;
  61   void OnWriteEnabled(const storage::FileSystemURL& url) override;
  62
  63   // Runs the given |task| if no sync operation is running on any of
  64   // its target_paths(). This also runs pending tasks that have become
  65   // runnable (before running the given operation).
  66   // If there're ongoing sync tasks on the target_paths this method
  67   // just queues up the |task|.
  68   // Pending tasks are cancelled when this class is destructed.
  69   void PostOperationTask(scoped_ptr<Task> task);
  70
  71   // Runs a next runnable task (if there's any).
  72   void RunNextRunnableTask();
  73
  74   // Called when an operation is completed. This will make |target_paths|
  75   // writable and may start a next runnable task.
  76   void OnOperationCompleted(
  77       const std::vector<storage::FileSystemURL>& target_paths);
  78
  79   LocalFileSyncStatus* sync_status() const { return sync_status_; }
  80
  81   int64 num_pending_tasks() const {
  82     return static_cast<int64>(pending_tasks_.size());
  83   }
  84
  85   int64 num_inflight_tasks() const { return num_inflight_tasks_; }
  86
  87  private:
  88   // Returns true if we should start more tasks.
  89   bool ShouldStartMoreTasks() const;
  90
  91   // Keeps track of the writing/syncing status. Not owned.
  92   LocalFileSyncStatus* sync_status_;
  93
  94   std::list<Task*> pending_tasks_;
  95
  96   const int64 max_inflight_tasks_;
  97   int64 num_inflight_tasks_;
  98
  99   DISALLOW_COPY_AND_ASSIGN(SyncableFileOperationRunner);
 100 };
 101
 102 }  // namespace sync_file_system
 103
 104 #endif  // CHROME_BROWSER_SYNC_FILE_SYSTEM_LOCAL_SYNCABLE_FILE_OPERATION_RUNNER_H_