// 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 CHROME_BROWSER_CHROMEOS_FILE_MANAGER_FILE_WATCHER_H_
#define CHROME_BROWSER_CHROMEOS_FILE_MANAGER_FILE_WATCHER_H_
#include <map>
#include <string>
#include "base/callback_forward.h"
#include "base/files/file_path.h"
#include "base/files/file_path_watcher.h"
#include "base/memory/weak_ptr.h"
namespace file_manager {
// This class is used to watch changes in the given virtual path, remember
// what extensions are watching the path.
//
// For local files, the class maintains a FilePathWatcher instance and
// remembers what extensions are watching the path.
//
// For remote files (ex. files on Drive), the class just remembers what
// extensions are watching the path. The actual file watching for remote
// files is handled differently in EventRouter.
class FileWatcher {
public:
typedef base::Callback<void(bool success)> BoolCallback;
// Creates a FileWatcher associated with the virtual path.
explicit FileWatcher(const base::FilePath& virtual_path);
~FileWatcher();
// Remembers that the extension of |extension_id| is watching the virtual
// path.
//
// If this function is called more than once with the same extension ID,
// the class increments the counter internally, and RemoveExtension()
// decrements the counter, and forgets the extension when the counter
// becomes zero.
void AddExtension(const std::string& extension_id);
// Forgets that the extension of |extension_id| is watching the virtual path,
// or just decrements the internal counter for the extension ID. See the
// comment at AddExtension() for details.
void RemoveExtension(const std::string& extension_id);
// Returns IDs of the extensions watching virtual_path. The returned list
// is sorted in the alphabetical order and contains no duplicates.
std::vector<std::string> GetExtensionIds() const;
// Returns the virtual path associated with the FileWatcher.
const base::FilePath& virtual_path() const { return virtual_path_; }
// Starts watching a local file at |local_path|. |file_watcher_callback|
// will be called when changes are notified.
//
// |callback| will be called with true, if the file watch is started
// successfully, or false if failed. |callback| must not be null.
void WatchLocalFile(
const base::FilePath& local_path,
const base::FilePathWatcher::Callback& file_watcher_callback,
const BoolCallback& callback);
private:
// Called when a FilePathWatcher is created and started.
// |file_path_watcher| is NULL, if the watcher wasn't started successfully.
void OnWatcherStarted(const BoolCallback& callback,
base::FilePathWatcher* file_path_watcher);
base::FilePathWatcher* local_file_watcher_;
base::FilePath virtual_path_;
// Map of extension-id to counter. See the comment at AddExtension() for
// why we need to count.
typedef std::map<std::string, int> ExtensionCountMap;
ExtensionCountMap extensions_;
// Note: This should remain the last member so it'll be destroyed and
// invalidate the weak pointers before any other members are destroyed.
base::WeakPtrFactory<FileWatcher> weak_ptr_factory_;
};
} // namespace file_manager
#endif // CHROME_BROWSER_CHROMEOS_FILE_MANAGER_FILE_WATCHER_H_