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// Copyright 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 WEBKIT_BROWSER_FILEAPI_SYNCABLE_LOCAL_FILE_SYNC_STATUS_H_
#define WEBKIT_BROWSER_FILEAPI_SYNCABLE_LOCAL_FILE_SYNC_STATUS_H_
#include <map>
#include <set>
#include "base/basictypes.h"
#include "base/compiler_specific.h"
#include "base/observer_list.h"
#include "base/threading/non_thread_safe.h"
#include "webkit/browser/fileapi/file_system_url.h"
namespace fileapi {
class FileSystemURL;
}
namespace sync_file_system {
// Represents local file sync status.
// This class is supposed to run only on IO thread.
//
// This class manages two important synchronization flags: writing (counter)
// and syncing (flag). Writing counter keeps track of which URL is in
// writing and syncing flag indicates which URL is in syncing.
//
// An entry can have multiple writers but sync is exclusive and cannot overwrap
// with any writes or syncs.
class WEBKIT_STORAGE_BROWSER_EXPORT LocalFileSyncStatus
: public base::NonThreadSafe {
public:
class WEBKIT_STORAGE_BROWSER_EXPORT Observer {
public:
Observer() {}
virtual ~Observer() {}
virtual void OnSyncEnabled(const fileapi::FileSystemURL& url) = 0;
virtual void OnWriteEnabled(const fileapi::FileSystemURL& url) = 0;
private:
DISALLOW_COPY_AND_ASSIGN(Observer);
};
LocalFileSyncStatus();
~LocalFileSyncStatus();
// Increment writing counter for |url|.
// This should not be called if the |url| is not writable.
void StartWriting(const fileapi::FileSystemURL& url);
// Decrement writing counter for |url|.
void EndWriting(const fileapi::FileSystemURL& url);
// Start syncing for |url| and disable writing.
// This should not be called if |url| is in syncing or in writing.
void StartSyncing(const fileapi::FileSystemURL& url);
// Clears the syncing flag for |url| and enable writing.
void EndSyncing(const fileapi::FileSystemURL& url);
// Returns true if the |url| or its parent or child is in writing.
bool IsWriting(const fileapi::FileSystemURL& url) const;
// Returns true if the |url| is enabled for writing (i.e. not in syncing).
bool IsWritable(const fileapi::FileSystemURL& url) const;
// Returns true if the |url| is enabled for syncing (i.e. neither in
// syncing nor writing).
bool IsSyncable(const fileapi::FileSystemURL& url) const;
void AddObserver(Observer* observer);
void RemoveObserver(Observer* observer);
private:
typedef std::map<fileapi::FileSystemURL,int64,
fileapi::FileSystemURL::Comparator> URLCountMap;
bool IsChildOrParentWriting(const fileapi::FileSystemURL& url) const;
bool IsChildOrParentSyncing(const fileapi::FileSystemURL& url) const;
// If this count is non-zero positive there're ongoing write operations.
URLCountMap writing_;
// If this flag is set sync process is running on the file.
fileapi::FileSystemURLSet syncing_;
ObserverList<Observer> observer_list_;
DISALLOW_COPY_AND_ASSIGN(LocalFileSyncStatus);
};
} // namespace sync_file_system
#endif // WEBKIT_BROWSER_FILEAPI_SYNCABLE_LOCAL_FILE_SYNC_STATUS_H_
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