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content / browser / file_system_access / file_path_watcher / file_path_watcher_fsevents.h [blame]
// Copyright 2024 The Chromium Authors
// Use of this source code is governed by a BSD-style license that can be
// found in the LICENSE file.
#ifndef CONTENT_BROWSER_FILE_SYSTEM_ACCESS_FILE_PATH_WATCHER_FILE_PATH_WATCHER_FSEVENTS_H_
#define CONTENT_BROWSER_FILE_SYSTEM_ACCESS_FILE_PATH_WATCHER_FILE_PATH_WATCHER_FSEVENTS_H_
#include <CoreServices/CoreServices.h>
#include <stddef.h>
#include <map>
#include <vector>
#include "base/apple/scoped_dispatch_object.h"
#include "base/files/file_path.h"
#include "base/memory/weak_ptr.h"
#include "content/browser/file_system_access/file_path_watcher/file_path_watcher.h"
#include "content/browser/file_system_access/file_path_watcher/file_path_watcher_histogram.h"
namespace content {
// Mac-specific file watcher implementation based on FSEvents.
// There are trade-offs between the FSEvents implementation and a kqueue
// implementation. The biggest issues are that FSEvents on 10.6 sometimes drops
// events and kqueue does not trigger for modifications to a file in a watched
// directory. See file_path_watcher_mac.cc for the code that decides when to
// use which one.
class FilePathWatcherFSEvents : public FilePathWatcher::PlatformDelegate {
public:
FilePathWatcherFSEvents();
FilePathWatcherFSEvents(const FilePathWatcherFSEvents&) = delete;
FilePathWatcherFSEvents& operator=(const FilePathWatcherFSEvents&) = delete;
~FilePathWatcherFSEvents() override;
// Represents a single FSEvents event.
struct ChangeEvent {
FSEventStreamEventFlags event_flags;
base::FilePath event_path;
std::optional<uint64_t> event_inode;
};
// FilePathWatcher::PlatformDelegate overrides.
bool Watch(const base::FilePath& path,
Type type,
const FilePathWatcher::Callback& callback) override;
bool WatchWithChangeInfo(
const base::FilePath& path,
const WatchOptions& options,
const FilePathWatcher::CallbackWithChangeInfo& callback) override;
void Cancel() override;
private:
static void FSEventsCallback(ConstFSEventStreamRef stream,
void* event_watcher,
size_t num_events,
void* event_paths,
const FSEventStreamEventFlags flags[],
const FSEventStreamEventId event_ids[]);
// Called on the watcher task runner from the FSEventsCallback whenever
// there is a change to the paths.
void OnFilePathsChanged(bool is_root_changed_event,
FSEventStreamEventId root_change_at,
std::map<FSEventStreamEventId, ChangeEvent> events);
// Called on the watcher task runner thread to dispatch path events.
void DispatchEvents(std::map<FSEventStreamEventId, ChangeEvent> events);
// (Re-)Initialize the event stream to start reporting events from
// |start_event|.
WatchWithChangeInfoResult UpdateEventStream(FSEventStreamEventId start_event);
// Returns true if resolving the target path got a different result than
// last time it was done.
bool ResolveTargetPath();
// Report an error watching the given target.
void ReportError(const base::FilePath& target);
// Destroy the event stream.
void DestroyEventStream();
// Start watching the FSEventStream. Returns `true` if the FS Events event
// stream starts successfully.
bool StartEventStream(FSEventStreamEventId start_event,
const base::FilePath& path);
bool recursive_watch_ = false;
bool report_modified_path_ = false;
// Callback to notify upon changes.
// (Only accessed from the task_runner() thread).
FilePathWatcher::CallbackWithChangeInfo callback_;
// The dispatch queue on which the event stream is scheduled.
base::apple::ScopedDispatchObject<dispatch_queue_t> queue_;
base::FilePath target_;
base::FilePath resolved_target_;
// Signals whether to check for a target deletion or creation event, and
// coalesce the event if needed.
bool coalesce_next_target_deletion_ = false;
bool coalesce_next_target_creation_ = false;
// Backend stream we receive event callbacks from (strong reference).
// (Only accessed from the libdispatch queue.)
FSEventStreamRef fsevent_stream_ = nullptr;
base::WeakPtrFactory<FilePathWatcherFSEvents> weak_factory_{this};
};
} // namespace content
#endif // CONTENT_BROWSER_FILE_SYSTEM_ACCESS_FILE_PATH_WATCHER_FILE_PATH_WATCHER_FSEVENTS_H_