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 * Copyright (C) 2010 Google Inc. All rights reserved.
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 * modification, are permitted provided that the following conditions are
 * met:
 *
 *     * Redistributions of source code must retain the above copyright
 * notice, this list of conditions and the following disclaimer.
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 * copyright notice, this list of conditions and the following disclaimer
 * in the documentation and/or other materials provided with the
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 * this software without specific prior written permission.
 *
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#ifndef AsyncFileSystem_h
#define AsyncFileSystem_h

#if ENABLE(FILE_SYSTEM)

#include "PlatformString.h"
#include "Timer.h"
#include <wtf/PassOwnPtr.h>

namespace WebCore {

class AsyncFileSystem;
class AsyncFileSystemCallbacks;
class AsyncFileWriterClient;

// This class provides async interface for platform-specific file system implementation.  Note that all the methods take platform paths.
class AsyncFileSystem {
    WTF_MAKE_NONCOPYABLE(AsyncFileSystem);
public:
    virtual ~AsyncFileSystem() { }

    // FileSystem type
    enum Type {
        Temporary,
        Persistent,
        External,
    };

    virtual void stop() { }
    virtual bool hasPendingActivity() { return false; }

    static bool isAvailable();

    // Subclass must implement this if it supports synchronous operations.
    // This should return false if there are no pending operations.
    virtual bool waitForOperationToComplete() { return false; }

    // Creates and returns a new platform-specific AsyncFileSystem instance if the platform has its own implementation.
    static PassOwnPtr<AsyncFileSystem> create(Type, const String& rootPath);

    // Opens a new file system. The create parameter specifies whether or not to create the path if it does not already exists.
    static void openFileSystem(const String& basePath, const String& storageIdentifier, Type, bool create, PassOwnPtr<AsyncFileSystemCallbacks>);

    // Moves a file or directory from srcPath to destPath.
    // AsyncFileSystemCallbacks::didSucceed() is called when the operation is completed successfully.
    // AsyncFileSystemCallbacks::didFail() is called otherwise.
    virtual void move(const String& srcPath, const String& destPath, PassOwnPtr<AsyncFileSystemCallbacks>) = 0;

    // Copies a file or directory from srcPath to destPath.
    // AsyncFileSystemCallbacks::didSucceed() is called when the operation is completed successfully.
    // AsyncFileSystemCallbacks::didFail() is called otherwise.
    virtual void copy(const String& srcPath, const String& destPath, PassOwnPtr<AsyncFileSystemCallbacks>) = 0;

    // Deletes a file or directory at a given path.
    // It is an error to try to remove a directory that is not empty.
    // AsyncFileSystemCallbacks::didSucceed() is called when the operation is completed successfully.
    // AsyncFileSystemCallbacks::didFail() is called otherwise.
    virtual void remove(const String& path, PassOwnPtr<AsyncFileSystemCallbacks>) = 0;

    // Recursively deletes a directory at a given path.
    // AsyncFileSystemCallbacks::didSucceed() is called when the operation is completed successfully.
    // AsyncFileSystemCallbacks::didFail() is called otherwise.
    virtual void removeRecursively(const String& path, PassOwnPtr<AsyncFileSystemCallbacks>) = 0;

    // Retrieves the metadata information of the file or directory at a given path.
    // AsyncFileSystemCallbacks::didReadMetadata() is called when the operation is completed successfully.
    // AsyncFileSystemCallbacks::didFail() is called otherwise.
    virtual void readMetadata(const String& path, PassOwnPtr<AsyncFileSystemCallbacks>) = 0;

    // Creates a file at a given path.  If exclusive flag is true, it fails if the path already exists.
    // AsyncFileSystemCallbacks::didSucceed() is called when the operation is completed successfully.
    // AsyncFileSystemCallbacks::didFail() is called otherwise.
    virtual void createFile(const String& path, bool exclusive, PassOwnPtr<AsyncFileSystemCallbacks>) = 0;

    // Creates a directory at a given path.  If exclusive flag is true, it fails if the path already exists.
    // AsyncFileSystemCallbacks::didSucceed() is called when the operation is completed successfully.
    // AsyncFileSystemCallbacks::didFail() is called otherwise.
    virtual void createDirectory(const String& path, bool exclusive, PassOwnPtr<AsyncFileSystemCallbacks>) = 0;

    // Checks if a file exists at a given path.
    // AsyncFileSystemCallbacks::didSucceed() is called if the file exists.
    // AsyncFileSystemCallbacks::didFail() is called otherwise.
    virtual void fileExists(const String& path, PassOwnPtr<AsyncFileSystemCallbacks>) = 0;

    // Checks if a directory exists at a given path.
    // AsyncFileSystemCallbacks::didSucceed() is called if the directory exists.
    // AsyncFileSystemCallbacks::didFail() is called otherwise.
    virtual void directoryExists(const String& path, PassOwnPtr<AsyncFileSystemCallbacks>) = 0;

    // Reads directory entries of a given directory at path.
    // AsyncFileSystemCallbacks::didReadDirectoryEntry() is called when each directory entry is called. AsyncFileSystemCallbacks::didReadDirectoryEntries() is called after a chunk of directory entries have been read.
    // AsyncFileSystemCallbacks::didFail() is when there is an error.
    virtual void readDirectory(const String& path, PassOwnPtr<AsyncFileSystemCallbacks>) = 0;

    // Creates an AsyncFileWriter for a given file path.
    // AsyncFileSystemCallbacks::didCreateFileWriter() is called when an AsyncFileWriter is created successfully.
    // AsyncFileSystemCallbacks::didFail() is called otherwise.
    virtual void createWriter(AsyncFileWriterClient* client, const String& path, PassOwnPtr<AsyncFileSystemCallbacks>) = 0;

    // Converts a given absolute virtual path to a platform path that starts with the platform root path of this file system.
    virtual String virtualToPlatformPath(const String& path) const;

    // Getter for this file system's root path.
    String root() const { return m_platformRootPath; }

    Type type() const { return m_type; }

protected:
    AsyncFileSystem(Type type, const String& platformRootPath)
        : m_type(type)
        , m_platformRootPath(platformRootPath)
    {
    }

    Type m_type;
    String m_platformRootPath;
};

} // namespace WebCore

#endif // ENABLE(FILE_SYSTEM)

#endif // AsyncFileSystem_h