webkit/fileapi/syncable/syncable_file_operation_runner.h

   1 // Copyright (c) 2012 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 WEBKIT_FILEAPI_SYNCABLE_SYNCABLE_FILE_OPERATION_RUNNER_H_
   6 #define WEBKIT_FILEAPI_SYNCABLE_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 "webkit/fileapi/file_system_url.h"
  17 #include "webkit/fileapi/syncable/local_file_sync_status.h"
  18 #include "webkit/storage/webkit_storage_export.h"
  19
  20 namespace fileapi {
  21 class FileSystemURL;
  22 }
  23
  24 namespace sync_file_system {
  25
  26 // This class must run only on IO thread.
  27 // Owned by LocalFileSyncContext.
  28 class WEBKIT_STORAGE_EXPORT SyncableFileOperationRunner
  29     : public base::NonThreadSafe,
  30       public base::SupportsWeakPtr<SyncableFileOperationRunner>,
  31       public LocalFileSyncStatus::Observer {
  32  public:
  33   // Represents an operation task (which usually wraps one FileSystemOperation).
  34   class Task {
  35    public:
  36     Task() {}
  37     virtual ~Task() {}
  38
  39     // Only one of Run() or Cancel() is called.
  40     virtual void Run() = 0;
  41     virtual void Cancel() = 0;
  42
  43    protected:
  44     // This is never called after Run() or Cancel() is called.
  45     virtual const std::vector<fileapi::FileSystemURL>& target_paths() const = 0;
  46
  47    private:
  48     friend class SyncableFileOperationRunner;
  49     bool IsRunnable(LocalFileSyncStatus* status) const;
  50     void Start(LocalFileSyncStatus* status);
  51     static void CancelAndDelete(Task* task);
  52
  53     DISALLOW_COPY_AND_ASSIGN(Task);
  54   };
  55
  56   SyncableFileOperationRunner(int64 max_inflight_tasks,
  57                               LocalFileSyncStatus* sync_status);
  58   virtual ~SyncableFileOperationRunner();
  59
  60   // LocalFileSyncStatus::Observer overrides.
  61   virtual void OnSyncEnabled(const fileapi::FileSystemURL& url) OVERRIDE;
  62   virtual void OnWriteEnabled(const fileapi::FileSystemURL& url) OVERRIDE;
  63
  64   // Runs the given |task| if no sync operation is running on any of
  65   // its target_paths(). This also runs pending tasks that have become
  66   // runnable (before running the given operation).
  67   // If there're ongoing sync tasks on the target_paths this method
  68   // just queues up the |task|.
  69   // Pending tasks are cancelled when this class is destructed.
  70   void PostOperationTask(scoped_ptr<Task> task);
  71
  72   // Runs a next runnable task (if there's any).
  73   void RunNextRunnableTask();
  74
  75   // Called when an operation is completed. This will make |target_paths|
  76   // writable and may start a next runnable task.
  77   void OnOperationCompleted(
  78       const std::vector<fileapi::FileSystemURL>& target_paths);
  79
  80   LocalFileSyncStatus* sync_status() const { return sync_status_; }
  81
  82   int64 num_pending_tasks() const {
  83     return static_cast<int64>(pending_tasks_.size());
  84   }
  85
  86   int64 num_inflight_tasks() const { return num_inflight_tasks_; }
  87
  88  private:
  89   // Returns true if we should start more tasks.
  90   bool ShouldStartMoreTasks() const;
  91
  92   // Keeps track of the writing/syncing status. Not owned.
  93   LocalFileSyncStatus* sync_status_;
  94
  95   std::list<Task*> pending_tasks_;
  96
  97   const int64 max_inflight_tasks_;
  98   int64 num_inflight_tasks_;
  99
 100   DISALLOW_COPY_AND_ASSIGN(SyncableFileOperationRunner);
 101 };
 102
 103 }  // namespace sync_file_system
 104
 105 #endif  // WEBKIT_FILEAPI_SYNCABLE_SYNCABLE_FILE_OPERATION_RUNNER_H_