| 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/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/lazy_instance.h" | |
| 24 #include "base/logging.h" | |
| 25 #include "base/message_loop.h" | |
| 26 #include "base/scoped_ptr.h" | |
| 27 #include "base/synchronization/lock.h" | |
| 28 #include "base/task.h" | |
| 29 #include "base/threading/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 ::base::DefaultLazyInstanceTraits<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 base::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 | |
| 86 // Called for each event coming from the watch. |fired_watch| identifies the | |
| 87 // watch that fired, |child| indicates what has changed, and is relative to | |
| 88 // the currently watched path for |fired_watch|. The flag |created| is true if | |
| 89 // the object appears, and |is_directory| is set when the event refers to a | |
| 90 // directory. | |
| 91 void OnFilePathChanged(InotifyReader::Watch fired_watch, | |
| 92 const FilePath::StringType& child, | |
| 93 bool created, | |
| 94 bool is_directory); | |
| 95 | |
| 96 // Start watching |path| for changes and notify |delegate| on each change. | |
| 97 // Returns true if watch for |path| has been added successfully. | |
| 98 virtual bool Watch(const FilePath& path, FilePathWatcher::Delegate* delegate); | |
| 99 | |
| 100 // Cancel the watch. This unregisters the instance with InotifyReader. | |
| 101 virtual void Cancel(); | |
| 102 | |
| 103 private: | |
| 104 virtual ~FilePathWatcherImpl() {} | |
| 105 | |
| 106 // Inotify watches are installed for all directory components of |target_|. A | |
| 107 // WatchEntry instance holds the watch descriptor for a component and the | |
| 108 // subdirectory for that identifies the next component. | |
| 109 struct WatchEntry { | |
| 110 WatchEntry(InotifyReader::Watch watch, const FilePath::StringType& subdir) | |
| 111 : watch_(watch), | |
| 112 subdir_(subdir) {} | |
| 113 | |
| 114 InotifyReader::Watch watch_; | |
| 115 FilePath::StringType subdir_; | |
| 116 }; | |
| 117 typedef std::vector<WatchEntry> WatchVector; | |
| 118 | |
| 119 // Reconfigure to watch for the most specific parent directory of |target_| | |
| 120 // that exists. Updates |watched_path_|. Returns true on success. | |
| 121 bool UpdateWatches() WARN_UNUSED_RESULT; | |
| 122 | |
| 123 // Delegate to notify upon changes. | |
| 124 scoped_refptr<FilePathWatcher::Delegate> delegate_; | |
| 125 | |
| 126 // The file or directory we're supposed to watch. | |
| 127 FilePath target_; | |
| 128 | |
| 129 // The vector of watches and next component names for all path components, | |
| 130 // starting at the root directory. The last entry corresponds to the watch for | |
| 131 // |target_| and always stores an empty next component name in |subdir_|. | |
| 132 WatchVector watches_; | |
| 133 | |
| 134 DISALLOW_COPY_AND_ASSIGN(FilePathWatcherImpl); | |
| 135 }; | |
| 136 | |
| 137 class InotifyReaderTask : public Task { | |
| 138 public: | |
| 139 InotifyReaderTask(InotifyReader* reader, int inotify_fd, int shutdown_fd) | |
| 140 : reader_(reader), | |
| 141 inotify_fd_(inotify_fd), | |
| 142 shutdown_fd_(shutdown_fd) { | |
| 143 } | |
| 144 | |
| 145 virtual void Run() { | |
| 146 while (true) { | |
| 147 fd_set rfds; | |
| 148 FD_ZERO(&rfds); | |
| 149 FD_SET(inotify_fd_, &rfds); | |
| 150 FD_SET(shutdown_fd_, &rfds); | |
| 151 | |
| 152 // Wait until some inotify events are available. | |
| 153 int select_result = | |
| 154 HANDLE_EINTR(select(std::max(inotify_fd_, shutdown_fd_) + 1, | |
| 155 &rfds, NULL, NULL, NULL)); | |
| 156 if (select_result < 0) { | |
| 157 DPLOG(WARNING) << "select failed"; | |
| 158 return; | |
| 159 } | |
| 160 | |
| 161 if (FD_ISSET(shutdown_fd_, &rfds)) | |
| 162 return; | |
| 163 | |
| 164 // Adjust buffer size to current event queue size. | |
| 165 int buffer_size; | |
| 166 int ioctl_result = HANDLE_EINTR(ioctl(inotify_fd_, FIONREAD, | |
| 167 &buffer_size)); | |
| 168 | |
| 169 if (ioctl_result != 0) { | |
| 170 DPLOG(WARNING) << "ioctl failed"; | |
| 171 return; | |
| 172 } | |
| 173 | |
| 174 std::vector<char> buffer(buffer_size); | |
| 175 | |
| 176 ssize_t bytes_read = HANDLE_EINTR(read(inotify_fd_, &buffer[0], | |
| 177 buffer_size)); | |
| 178 | |
| 179 if (bytes_read < 0) { | |
| 180 DPLOG(WARNING) << "read from inotify fd failed"; | |
| 181 return; | |
| 182 } | |
| 183 | |
| 184 ssize_t i = 0; | |
| 185 while (i < bytes_read) { | |
| 186 inotify_event* event = reinterpret_cast<inotify_event*>(&buffer[i]); | |
| 187 size_t event_size = sizeof(inotify_event) + event->len; | |
| 188 DCHECK(i + event_size <= static_cast<size_t>(bytes_read)); | |
| 189 reader_->OnInotifyEvent(event); | |
| 190 i += event_size; | |
| 191 } | |
| 192 } | |
| 193 } | |
| 194 | |
| 195 private: | |
| 196 InotifyReader* reader_; | |
| 197 int inotify_fd_; | |
| 198 int shutdown_fd_; | |
| 199 | |
| 200 DISALLOW_COPY_AND_ASSIGN(InotifyReaderTask); | |
| 201 }; | |
| 202 | |
| 203 static base::LazyInstance<InotifyReader> g_inotify_reader( | |
| 204 base::LINKER_INITIALIZED); | |
| 205 | |
| 206 InotifyReader::InotifyReader() | |
| 207 : thread_("inotify_reader"), | |
| 208 inotify_fd_(inotify_init()), | |
| 209 valid_(false) { | |
| 210 shutdown_pipe_[0] = -1; | |
| 211 shutdown_pipe_[1] = -1; | |
| 212 if (inotify_fd_ >= 0 && pipe(shutdown_pipe_) == 0 && thread_.Start()) { | |
| 213 thread_.message_loop()->PostTask( | |
| 214 FROM_HERE, new InotifyReaderTask(this, inotify_fd_, shutdown_pipe_[0])); | |
| 215 valid_ = true; | |
| 216 } | |
| 217 } | |
| 218 | |
| 219 InotifyReader::~InotifyReader() { | |
| 220 if (valid_) { | |
| 221 // Write to the self-pipe so that the select call in InotifyReaderTask | |
| 222 // returns. | |
| 223 ssize_t ret = HANDLE_EINTR(write(shutdown_pipe_[1], "", 1)); | |
| 224 DPCHECK(ret > 0); | |
| 225 DCHECK_EQ(ret, 1); | |
| 226 thread_.Stop(); | |
| 227 } | |
| 228 if (inotify_fd_ >= 0) | |
| 229 close(inotify_fd_); | |
| 230 if (shutdown_pipe_[0] >= 0) | |
| 231 close(shutdown_pipe_[0]); | |
| 232 if (shutdown_pipe_[1] >= 0) | |
| 233 close(shutdown_pipe_[1]); | |
| 234 } | |
| 235 | |
| 236 InotifyReader::Watch InotifyReader::AddWatch( | |
| 237 const FilePath& path, FilePathWatcherImpl* watcher) { | |
| 238 if (!valid_) | |
| 239 return kInvalidWatch; | |
| 240 | |
| 241 base::AutoLock auto_lock(lock_); | |
| 242 | |
| 243 Watch watch = inotify_add_watch(inotify_fd_, path.value().c_str(), | |
| 244 IN_CREATE | IN_DELETE | | |
| 245 IN_CLOSE_WRITE | IN_MOVE | | |
| 246 IN_ONLYDIR); | |
| 247 | |
| 248 if (watch == kInvalidWatch) | |
| 249 return kInvalidWatch; | |
| 250 | |
| 251 watchers_[watch].insert(watcher); | |
| 252 | |
| 253 return watch; | |
| 254 } | |
| 255 | |
| 256 bool InotifyReader::RemoveWatch(Watch watch, | |
| 257 FilePathWatcherImpl* watcher) { | |
| 258 if (!valid_) | |
| 259 return false; | |
| 260 | |
| 261 base::AutoLock auto_lock(lock_); | |
| 262 | |
| 263 watchers_[watch].erase(watcher); | |
| 264 | |
| 265 if (watchers_[watch].empty()) { | |
| 266 watchers_.erase(watch); | |
| 267 return (inotify_rm_watch(inotify_fd_, watch) == 0); | |
| 268 } | |
| 269 | |
| 270 return true; | |
| 271 } | |
| 272 | |
| 273 void InotifyReader::OnInotifyEvent(const inotify_event* event) { | |
| 274 if (event->mask & IN_IGNORED) | |
| 275 return; | |
| 276 | |
| 277 FilePath::StringType child(event->len ? event->name : FILE_PATH_LITERAL("")); | |
| 278 base::AutoLock auto_lock(lock_); | |
| 279 | |
| 280 for (WatcherSet::iterator watcher = watchers_[event->wd].begin(); | |
| 281 watcher != watchers_[event->wd].end(); | |
| 282 ++watcher) { | |
| 283 BrowserThread::PostTask(BrowserThread::FILE, FROM_HERE, | |
| 284 NewRunnableMethod(*watcher, | |
| 285 &FilePathWatcherImpl::OnFilePathChanged, | |
| 286 event->wd, | |
| 287 child, | |
| 288 event->mask & (IN_CREATE | IN_MOVED_TO), | |
| 289 event->mask & IN_ISDIR)); | |
| 290 } | |
| 291 } | |
| 292 | |
| 293 FilePathWatcherImpl::FilePathWatcherImpl() | |
| 294 : delegate_(NULL) { | |
| 295 } | |
| 296 | |
| 297 void FilePathWatcherImpl::OnFilePathChanged(InotifyReader::Watch fired_watch, | |
| 298 const FilePath::StringType& child, | |
| 299 bool created, | |
| 300 bool is_directory) { | |
| 301 DCHECK(BrowserThread::CurrentlyOn(BrowserThread::FILE)); | |
| 302 | |
| 303 // Find the entry in |watches_| that corresponds to |fired_watch|. | |
| 304 WatchVector::const_iterator watch_entry(watches_.begin()); | |
| 305 for ( ; watch_entry != watches_.end(); ++watch_entry) { | |
| 306 if (fired_watch == watch_entry->watch_) | |
| 307 break; | |
| 308 } | |
| 309 | |
| 310 // If this notification is from a previous generation of watches or the watch | |
| 311 // has been cancelled (|watches_| is empty then), bail out. | |
| 312 if (watch_entry == watches_.end()) | |
| 313 return; | |
| 314 | |
| 315 // Check whether a path component of |target_| changed. | |
| 316 bool change_on_target_path = child.empty() || child == watch_entry->subdir_; | |
| 317 | |
| 318 // Check whether the change references |target_| or a direct child. | |
| 319 DCHECK(watch_entry->subdir_.empty() || (watch_entry + 1) != watches_.end()); | |
| 320 bool target_changed = watch_entry->subdir_.empty() || | |
| 321 (watch_entry->subdir_ == child && (++watch_entry)->subdir_.empty()); | |
| 322 | |
| 323 // Update watches if a directory component of the |target_| path (dis)appears. | |
| 324 if (is_directory && change_on_target_path && !UpdateWatches()) { | |
| 325 delegate_->OnError(); | |
| 326 return; | |
| 327 } | |
| 328 | |
| 329 // Report the following events: | |
| 330 // - The target or a direct child of the target got changed (in case the | |
| 331 // watched path refers to a directory). | |
| 332 // - One of the parent directories got moved or deleted, since the target | |
| 333 // disappears in this case. | |
| 334 // - One of the parent directories appears. The event corresponding to the | |
| 335 // target appearing might have been missed in this case, so recheck. | |
| 336 if (target_changed || | |
| 337 (change_on_target_path && !created) || | |
| 338 (change_on_target_path && file_util::PathExists(target_))) { | |
| 339 delegate_->OnFilePathChanged(target_); | |
| 340 } | |
| 341 } | |
| 342 | |
| 343 bool FilePathWatcherImpl::Watch(const FilePath& path, | |
| 344 FilePathWatcher::Delegate* delegate) { | |
| 345 DCHECK(BrowserThread::CurrentlyOn(BrowserThread::FILE)); | |
| 346 DCHECK(target_.empty()); | |
| 347 | |
| 348 delegate_ = delegate; | |
| 349 target_ = path; | |
| 350 std::vector<FilePath::StringType> comps; | |
| 351 target_.GetComponents(&comps); | |
| 352 DCHECK(!comps.empty()); | |
| 353 for (std::vector<FilePath::StringType>::const_iterator comp(++comps.begin()); | |
| 354 comp != comps.end(); ++comp) { | |
| 355 watches_.push_back(WatchEntry(InotifyReader::kInvalidWatch, *comp)); | |
| 356 } | |
| 357 watches_.push_back(WatchEntry(InotifyReader::kInvalidWatch, | |
| 358 FilePath::StringType())); | |
| 359 return UpdateWatches(); | |
| 360 } | |
| 361 | |
| 362 void FilePathWatcherImpl::Cancel() { | |
| 363 // Switch to the file thread if necessary so we can access |watches_|. | |
| 364 if (!BrowserThread::CurrentlyOn(BrowserThread::FILE)) { | |
| 365 BrowserThread::PostTask(BrowserThread::FILE, FROM_HERE, | |
| 366 NewRunnableMethod(this, &FilePathWatcherImpl::Cancel)); | |
| 367 return; | |
| 368 } | |
| 369 | |
| 370 for (WatchVector::iterator watch_entry(watches_.begin()); | |
| 371 watch_entry != watches_.end(); ++watch_entry) { | |
| 372 if (watch_entry->watch_ != InotifyReader::kInvalidWatch) | |
| 373 g_inotify_reader.Get().RemoveWatch(watch_entry->watch_, this); | |
| 374 } | |
| 375 watches_.clear(); | |
| 376 delegate_ = NULL; | |
| 377 target_.clear(); | |
| 378 } | |
| 379 | |
| 380 bool FilePathWatcherImpl::UpdateWatches() { | |
| 381 // Ensure this runs on the file thread exclusively in order to avoid | |
| 382 // concurrency issues. | |
| 383 DCHECK(BrowserThread::CurrentlyOn(BrowserThread::FILE)); | |
| 384 | |
| 385 // Walk the list of watches and update them as we go. | |
| 386 FilePath path(FILE_PATH_LITERAL("/")); | |
| 387 bool path_valid = true; | |
| 388 for (WatchVector::iterator watch_entry(watches_.begin()); | |
| 389 watch_entry != watches_.end(); ++watch_entry) { | |
| 390 InotifyReader::Watch old_watch = watch_entry->watch_; | |
| 391 if (path_valid) { | |
| 392 watch_entry->watch_ = g_inotify_reader.Get().AddWatch(path, this); | |
| 393 if (watch_entry->watch_ == InotifyReader::kInvalidWatch) { | |
| 394 path_valid = false; | |
| 395 } | |
| 396 } else { | |
| 397 watch_entry->watch_ = InotifyReader::kInvalidWatch; | |
| 398 } | |
| 399 if (old_watch != InotifyReader::kInvalidWatch && | |
| 400 old_watch != watch_entry->watch_) { | |
| 401 g_inotify_reader.Get().RemoveWatch(old_watch, this); | |
| 402 } | |
| 403 path = path.Append(watch_entry->subdir_); | |
| 404 } | |
| 405 | |
| 406 return true; | |
| 407 } | |
| 408 | |
| 409 } // namespace | |
| 410 | |
| 411 FilePathWatcher::FilePathWatcher() { | |
| 412 impl_ = new FilePathWatcherImpl(); | |
| 413 } | |
| OLD | NEW |
|---|
Chromium Code Reviews
Issue 6825063:
Patch for bug 74983 (among others) to be applied to M11 696 branch. (Closed)
Base URL: svn://svn.chromium.org/chrome/branches/696/src