| OLD | NEW |
|---|
| (Empty) |
| 1 // Copyright (c) 2010 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 #include "chrome/browser/file_path_watcher.h" | |
| 6 | |
| 7 #include <errno.h> | |
| 8 #include <string.h> | |
| 9 #include <sys/inotify.h> | |
| 10 #include <sys/ioctl.h> | |
| 11 #include <sys/select.h> | |
| 12 #include <unistd.h> | |
| 13 | |
| 14 #include <algorithm> | |
| 15 #include <set> | |
| 16 #include <utility> | |
| 17 #include <vector> | |
| 18 | |
| 19 #include "base/eintr_wrapper.h" | |
| 20 #include "base/file_path.h" | |
| 21 #include "base/file_util.h" | |
| 22 #include "base/hash_tables.h" | |
| 23 #include "base/lock.h" | |
| 24 #include "base/logging.h" | |
| 25 #include "base/message_loop.h" | |
| 26 #include "base/scoped_ptr.h" | |
| 27 #include "base/singleton.h" | |
| 28 #include "base/task.h" | |
| 29 #include "base/thread.h" | |
| 30 | |
| 31 namespace { | |
| 32 | |
| 33 class FilePathWatcherImpl; | |
| 34 | |
| 35 // Singleton to manage all inotify watches. | |
| 36 // TODO(tony): It would be nice if this wasn't a singleton. | |
| 37 // http://crbug.com/38174 | |
| 38 class InotifyReader { | |
| 39 public: | |
| 40 typedef int Watch; // Watch descriptor used by AddWatch and RemoveWatch. | |
| 41 static const Watch kInvalidWatch = -1; | |
| 42 | |
| 43 // Watch directory |path| for changes. |watcher| will be notified on each | |
| 44 // change. Returns kInvalidWatch on failure. | |
| 45 Watch AddWatch(const FilePath& path, FilePathWatcherImpl* watcher); | |
| 46 | |
| 47 // Remove |watch|. Returns true on success. | |
| 48 bool RemoveWatch(Watch watch, FilePathWatcherImpl* watcher); | |
| 49 | |
| 50 // Callback for InotifyReaderTask. | |
| 51 void OnInotifyEvent(const inotify_event* event); | |
| 52 | |
| 53 private: | |
| 54 friend struct DefaultSingletonTraits<InotifyReader>; | |
| 55 | |
| 56 typedef std::set<FilePathWatcherImpl*> WatcherSet; | |
| 57 | |
| 58 InotifyReader(); | |
| 59 ~InotifyReader(); | |
| 60 | |
| 61 // We keep track of which delegates want to be notified on which watches. | |
| 62 base::hash_map<Watch, WatcherSet> watchers_; | |
| 63 | |
| 64 // Lock to protect watchers_. | |
| 65 Lock lock_; | |
| 66 | |
| 67 // Separate thread on which we run blocking read for inotify events. | |
| 68 base::Thread thread_; | |
| 69 | |
| 70 // File descriptor returned by inotify_init. | |
| 71 const int inotify_fd_; | |
| 72 | |
| 73 // Use self-pipe trick to unblock select during shutdown. | |
| 74 int shutdown_pipe_[2]; | |
| 75 | |
| 76 // Flag set to true when startup was successful. | |
| 77 bool valid_; | |
| 78 | |
| 79 DISALLOW_COPY_AND_ASSIGN(InotifyReader); | |
| 80 }; | |
| 81 | |
| 82 class FilePathWatcherImpl : public FilePathWatcher::PlatformDelegate { | |
| 83 public: | |
| 84 FilePathWatcherImpl(); | |
| 85 virtual ~FilePathWatcherImpl() {} | |
| 86 | |
| 87 // Called for each event coming from the watch. |fired_watch| identifies the | |
| 88 // watch that fired, |child| indicates what has changed, and is relative to | |
| 89 // the currently watched path for |fired_watch|. The flag |created| is true if | |
| 90 // the object appears, and |is_directory| is set when the event refers to a | |
| 91 // directory. | |
| 92 void OnFilePathChanged(InotifyReader::Watch fired_watch, | |
| 93 const FilePath::StringType& child, | |
| 94 bool created, | |
| 95 bool is_directory); | |
| 96 | |
| 97 // Start watching |path| for changes and notify |delegate| on each change. | |
| 98 // Returns true if watch for |path| has been added successfully. | |
| 99 virtual bool Watch(const FilePath& path, FilePathWatcher::Delegate* delegate); | |
| 100 | |
| 101 // Cancel the watch. This unregisters the instance with InotifyReader. | |
| 102 virtual void Cancel(); | |
| 103 | |
| 104 private: | |
| 105 // Inotify watches are installed for all directory components of |target_|. A | |
| 106 // WatchEntry instance holds the watch descriptor for a component and the | |
| 107 // subdirectory for that identifies the next component. | |
| 108 struct WatchEntry { | |
| 109 WatchEntry(InotifyReader::Watch watch, const FilePath::StringType& subdir) | |
| 110 : watch_(watch), | |
| 111 subdir_(subdir) {} | |
| 112 | |
| 113 InotifyReader::Watch watch_; | |
| 114 FilePath::StringType subdir_; | |
| 115 }; | |
| 116 typedef std::vector<WatchEntry> WatchVector; | |
| 117 | |
| 118 // Reconfigure to watch for the most specific parent directory of |target_| | |
| 119 // that exists. Updates |watched_path_|. Returns true on success. | |
| 120 bool UpdateWatches() WARN_UNUSED_RESULT; | |
| 121 | |
| 122 // Delegate to notify upon changes. | |
| 123 scoped_refptr<FilePathWatcher::Delegate> delegate_; | |
| 124 | |
| 125 // The file or directory we're supposed to watch. | |
| 126 FilePath target_; | |
| 127 | |
| 128 // The vector of watches and next component names for all path components, | |
| 129 // starting at the root directory. The last entry corresponds to the watch for | |
| 130 // |target_| and always stores an empty next component name in |subdir_|. | |
| 131 WatchVector watches_; | |
| 132 | |
| 133 DISALLOW_COPY_AND_ASSIGN(FilePathWatcherImpl); | |
| 134 }; | |
| 135 | |
| 136 class InotifyReaderTask : public Task { | |
| 137 public: | |
| 138 InotifyReaderTask(InotifyReader* reader, int inotify_fd, int shutdown_fd) | |
| 139 : reader_(reader), | |
| 140 inotify_fd_(inotify_fd), | |
| 141 shutdown_fd_(shutdown_fd) { | |
| 142 } | |
| 143 | |
| 144 virtual void Run() { | |
| 145 while (true) { | |
| 146 fd_set rfds; | |
| 147 FD_ZERO(&rfds); | |
| 148 FD_SET(inotify_fd_, &rfds); | |
| 149 FD_SET(shutdown_fd_, &rfds); | |
| 150 | |
| 151 // Wait until some inotify events are available. | |
| 152 int select_result = | |
| 153 HANDLE_EINTR(select(std::max(inotify_fd_, shutdown_fd_) + 1, | |
| 154 &rfds, NULL, NULL, NULL)); | |
| 155 if (select_result < 0) { | |
| 156 DPLOG(WARNING) << "select failed"; | |
| 157 return; | |
| 158 } | |
| 159 | |
| 160 if (FD_ISSET(shutdown_fd_, &rfds)) | |
| 161 return; | |
| 162 | |
| 163 // Adjust buffer size to current event queue size. | |
| 164 int buffer_size; | |
| 165 int ioctl_result = HANDLE_EINTR(ioctl(inotify_fd_, FIONREAD, | |
| 166 &buffer_size)); | |
| 167 | |
| 168 if (ioctl_result != 0) { | |
| 169 DPLOG(WARNING) << "ioctl failed"; | |
| 170 return; | |
| 171 } | |
| 172 | |
| 173 std::vector<char> buffer(buffer_size); | |
| 174 | |
| 175 ssize_t bytes_read = HANDLE_EINTR(read(inotify_fd_, &buffer[0], | |
| 176 buffer_size)); | |
| 177 | |
| 178 if (bytes_read < 0) { | |
| 179 DPLOG(WARNING) << "read from inotify fd failed"; | |
| 180 return; | |
| 181 } | |
| 182 | |
| 183 ssize_t i = 0; | |
| 184 while (i < bytes_read) { | |
| 185 inotify_event* event = reinterpret_cast<inotify_event*>(&buffer[i]); | |
| 186 size_t event_size = sizeof(inotify_event) + event->len; | |
| 187 DCHECK(i + event_size <= static_cast<size_t>(bytes_read)); | |
| 188 reader_->OnInotifyEvent(event); | |
| 189 i += event_size; | |
| 190 } | |
| 191 } | |
| 192 } | |
| 193 | |
| 194 private: | |
| 195 InotifyReader* reader_; | |
| 196 int inotify_fd_; | |
| 197 int shutdown_fd_; | |
| 198 | |
| 199 DISALLOW_COPY_AND_ASSIGN(InotifyReaderTask); | |
| 200 }; | |
| 201 | |
| 202 InotifyReader::InotifyReader() | |
| 203 : thread_("inotify_reader"), | |
| 204 inotify_fd_(inotify_init()), | |
| 205 valid_(false) { | |
| 206 shutdown_pipe_[0] = -1; | |
| 207 shutdown_pipe_[1] = -1; | |
| 208 if (inotify_fd_ >= 0 && pipe(shutdown_pipe_) == 0 && thread_.Start()) { | |
| 209 thread_.message_loop()->PostTask( | |
| 210 FROM_HERE, new InotifyReaderTask(this, inotify_fd_, shutdown_pipe_[0])); | |
| 211 valid_ = true; | |
| 212 } | |
| 213 } | |
| 214 | |
| 215 InotifyReader::~InotifyReader() { | |
| 216 if (valid_) { | |
| 217 // Write to the self-pipe so that the select call in InotifyReaderTask | |
| 218 // returns. | |
| 219 ssize_t ret = HANDLE_EINTR(write(shutdown_pipe_[1], "", 1)); | |
| 220 DPCHECK(ret > 0); | |
| 221 DCHECK_EQ(ret, 1); | |
| 222 thread_.Stop(); | |
| 223 } | |
| 224 if (inotify_fd_ >= 0) | |
| 225 close(inotify_fd_); | |
| 226 if (shutdown_pipe_[0] >= 0) | |
| 227 close(shutdown_pipe_[0]); | |
| 228 if (shutdown_pipe_[1] >= 0) | |
| 229 close(shutdown_pipe_[1]); | |
| 230 } | |
| 231 | |
| 232 InotifyReader::Watch InotifyReader::AddWatch( | |
| 233 const FilePath& path, FilePathWatcherImpl* watcher) { | |
| 234 if (!valid_) | |
| 235 return kInvalidWatch; | |
| 236 | |
| 237 AutoLock auto_lock(lock_); | |
| 238 | |
| 239 Watch watch = inotify_add_watch(inotify_fd_, path.value().c_str(), | |
| 240 IN_CREATE | IN_DELETE | | |
| 241 IN_CLOSE_WRITE | IN_MOVE | | |
| 242 IN_ONLYDIR); | |
| 243 | |
| 244 if (watch == kInvalidWatch) | |
| 245 return kInvalidWatch; | |
| 246 | |
| 247 watchers_[watch].insert(watcher); | |
| 248 | |
| 249 return watch; | |
| 250 } | |
| 251 | |
| 252 bool InotifyReader::RemoveWatch(Watch watch, | |
| 253 FilePathWatcherImpl* watcher) { | |
| 254 if (!valid_) | |
| 255 return false; | |
| 256 | |
| 257 AutoLock auto_lock(lock_); | |
| 258 | |
| 259 watchers_[watch].erase(watcher); | |
| 260 | |
| 261 if (watchers_[watch].empty()) { | |
| 262 watchers_.erase(watch); | |
| 263 return (inotify_rm_watch(inotify_fd_, watch) == 0); | |
| 264 } | |
| 265 | |
| 266 return true; | |
| 267 } | |
| 268 | |
| 269 void InotifyReader::OnInotifyEvent(const inotify_event* event) { | |
| 270 if (event->mask & IN_IGNORED) | |
| 271 return; | |
| 272 | |
| 273 FilePath::StringType child(event->len ? event->name : FILE_PATH_LITERAL("")); | |
| 274 AutoLock auto_lock(lock_); | |
| 275 | |
| 276 for (WatcherSet::iterator watcher = watchers_[event->wd].begin(); | |
| 277 watcher != watchers_[event->wd].end(); | |
| 278 ++watcher) { | |
| 279 BrowserThread::PostTask(BrowserThread::FILE, FROM_HERE, | |
| 280 NewRunnableMethod(*watcher, | |
| 281 &FilePathWatcherImpl::OnFilePathChanged, | |
| 282 event->wd, | |
| 283 child, | |
| 284 event->mask & (IN_CREATE | IN_MOVED_TO), | |
| 285 event->mask & IN_ISDIR)); | |
| 286 } | |
| 287 } | |
| 288 | |
| 289 FilePathWatcherImpl::FilePathWatcherImpl() | |
| 290 : delegate_(NULL) { | |
| 291 } | |
| 292 | |
| 293 void FilePathWatcherImpl::OnFilePathChanged(InotifyReader::Watch fired_watch, | |
| 294 const FilePath::StringType& child, | |
| 295 bool created, | |
| 296 bool is_directory) { | |
| 297 DCHECK(BrowserThread::CurrentlyOn(BrowserThread::FILE)); | |
| 298 | |
| 299 // Find the entry in |watches_| that corresponds to |fired_watch|. | |
| 300 WatchVector::const_iterator watch_entry(watches_.begin()); | |
| 301 for ( ; watch_entry != watches_.end(); ++watch_entry) { | |
| 302 if (fired_watch == watch_entry->watch_) | |
| 303 break; | |
| 304 } | |
| 305 | |
| 306 // If this notification is from a previous generation of watches or the watch | |
| 307 // has been cancelled (|watches_| is empty then), bail out. | |
| 308 if (watch_entry == watches_.end()) | |
| 309 return; | |
| 310 | |
| 311 // Check whether a path component of |target_| changed. | |
| 312 bool change_on_target_path = child.empty() || child == watch_entry->subdir_; | |
| 313 | |
| 314 // Check whether the change references |target_| or a direct child. | |
| 315 DCHECK(watch_entry->subdir_.empty() || (watch_entry + 1) != watches_.end()); | |
| 316 bool target_changed = watch_entry->subdir_.empty() || | |
| 317 (watch_entry->subdir_ == child && (++watch_entry)->subdir_.empty()); | |
| 318 | |
| 319 // Update watches if a directory component of the |target_| path (dis)appears. | |
| 320 if (is_directory && change_on_target_path && !UpdateWatches()) { | |
| 321 delegate_->OnError(); | |
| 322 return; | |
| 323 } | |
| 324 | |
| 325 // Report the following events: | |
| 326 // - The target or a direct child of the target got changed (in case the | |
| 327 // watched path refers to a directory). | |
| 328 // - One of the parent directories got moved or deleted, since the target | |
| 329 // disappears in this case. | |
| 330 // - One of the parent directories appears. The event corresponding to the | |
| 331 // target appearing might have been missed in this case, so recheck. | |
| 332 if (target_changed || | |
| 333 (change_on_target_path && !created) || | |
| 334 (change_on_target_path && file_util::PathExists(target_))) { | |
| 335 delegate_->OnFilePathChanged(target_); | |
| 336 } | |
| 337 } | |
| 338 | |
| 339 bool FilePathWatcherImpl::Watch(const FilePath& path, | |
| 340 FilePathWatcher::Delegate* delegate) { | |
| 341 DCHECK(BrowserThread::CurrentlyOn(BrowserThread::FILE)); | |
| 342 DCHECK(target_.empty()); | |
| 343 | |
| 344 delegate_ = delegate; | |
| 345 target_ = path; | |
| 346 std::vector<FilePath::StringType> comps; | |
| 347 target_.GetComponents(&comps); | |
| 348 DCHECK(!comps.empty()); | |
| 349 for (std::vector<FilePath::StringType>::const_iterator comp(++comps.begin()); | |
| 350 comp != comps.end(); ++comp) { | |
| 351 watches_.push_back(WatchEntry(InotifyReader::kInvalidWatch, *comp)); | |
| 352 } | |
| 353 watches_.push_back(WatchEntry(InotifyReader::kInvalidWatch, | |
| 354 FilePath::StringType())); | |
| 355 return UpdateWatches(); | |
| 356 } | |
| 357 | |
| 358 void FilePathWatcherImpl::Cancel() { | |
| 359 // Switch to the file thread if necessary so we can access |watches_|. | |
| 360 if (!BrowserThread::CurrentlyOn(BrowserThread::FILE)) { | |
| 361 BrowserThread::PostTask(BrowserThread::FILE, FROM_HERE, | |
| 362 NewRunnableMethod(this, &FilePathWatcherImpl::Cancel)); | |
| 363 return; | |
| 364 } | |
| 365 | |
| 366 for (WatchVector::iterator watch_entry(watches_.begin()); | |
| 367 watch_entry != watches_.end(); ++watch_entry) { | |
| 368 if (watch_entry->watch_ != InotifyReader::kInvalidWatch) | |
| 369 Singleton<InotifyReader>::get()->RemoveWatch(watch_entry->watch_, this); | |
| 370 } | |
| 371 watches_.clear(); | |
| 372 delegate_ = NULL; | |
| 373 target_.clear(); | |
| 374 } | |
| 375 | |
| 376 bool FilePathWatcherImpl::UpdateWatches() { | |
| 377 // Ensure this runs on the file thread exclusively in order to avoid | |
| 378 // concurrency issues. | |
| 379 DCHECK(BrowserThread::CurrentlyOn(BrowserThread::FILE)); | |
| 380 | |
| 381 // Walk the list of watches and update them as we go. | |
| 382 FilePath path(FILE_PATH_LITERAL("/")); | |
| 383 bool path_valid = true; | |
| 384 for (WatchVector::iterator watch_entry(watches_.begin()); | |
| 385 watch_entry != watches_.end(); ++watch_entry) { | |
| 386 InotifyReader::Watch old_watch = watch_entry->watch_; | |
| 387 if (path_valid) { | |
| 388 watch_entry->watch_ = | |
| 389 Singleton<InotifyReader>::get()->AddWatch(path, this); | |
| 390 if (watch_entry->watch_ == InotifyReader::kInvalidWatch) { | |
| 391 path_valid = false; | |
| 392 } | |
| 393 } else { | |
| 394 watch_entry->watch_ = InotifyReader::kInvalidWatch; | |
| 395 } | |
| 396 if (old_watch != InotifyReader::kInvalidWatch && | |
| 397 old_watch != watch_entry->watch_) { | |
| 398 Singleton<InotifyReader>::get()->RemoveWatch(old_watch, this); | |
| 399 } | |
| 400 path = path.Append(watch_entry->subdir_); | |
| 401 } | |
| 402 | |
| 403 return true; | |
| 404 } | |
| 405 | |
| 406 } // namespace | |
| 407 | |
| 408 FilePathWatcher::FilePathWatcher() { | |
| 409 impl_ = new FilePathWatcherImpl(); | |
| 410 } | |
| OLD | NEW |
|---|
Chromium Code Reviews
