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authormnissler@chromium.org <mnissler@chromium.org@0039d316-1c4b-4281-b951-d872f2087c98>2010-08-17 15:04:42 +0000
committermnissler@chromium.org <mnissler@chromium.org@0039d316-1c4b-4281-b951-d872f2087c98>2010-08-17 15:04:42 +0000
commitc369ffd33760e7b2f6aad22b3747dff321bf497a (patch)
tree18a08bfd012b1f17f24f22042e7af4dd2fe541e9 /chrome/browser/file_path_watcher_win.cc
parent9d03e7300b24129e53ac5f7894c003336c35f170 (diff)
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Revert 56341 - Add support for watching directories to FileWatcher.
BUG=none TEST=Unit tests in file_watcher_unittest.cc. Review URL: http://codereview.chromium.org/3149004 TBR=mnissler@chromium.org Review URL: http://codereview.chromium.org/3165027 git-svn-id: svn://svn.chromium.org/chrome/trunk/src@56349 0039d316-1c4b-4281-b951-d872f2087c98
Diffstat (limited to 'chrome/browser/file_path_watcher_win.cc')
-rw-r--r--chrome/browser/file_path_watcher_win.cc228
1 files changed, 0 insertions, 228 deletions
diff --git a/chrome/browser/file_path_watcher_win.cc b/chrome/browser/file_path_watcher_win.cc
deleted file mode 100644
index 03cb318..0000000
--- a/chrome/browser/file_path_watcher_win.cc
+++ /dev/null
@@ -1,228 +0,0 @@
-// Copyright (c) 2009 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.
-
-#include "chrome/browser/file_path_watcher.h"
-
-#include "base/file_path.h"
-#include "base/file_util.h"
-#include "base/logging.h"
-#include "base/object_watcher.h"
-#include "base/ref_counted.h"
-#include "base/time.h"
-
-namespace {
-
-class FilePathWatcherImpl : public FilePathWatcher::PlatformDelegate,
- public base::ObjectWatcher::Delegate {
- public:
- FilePathWatcherImpl() : delegate_(NULL), handle_(INVALID_HANDLE_VALUE) {}
-
- virtual bool Watch(const FilePath& path, FilePathWatcher::Delegate* delegate);
-
- // Callback from MessageLoopForIO.
- virtual void OnObjectSignaled(HANDLE object);
-
- private:
- virtual ~FilePathWatcherImpl();
-
- // Setup a watch handle for directory |dir|. Returns true if no fatal error
- // occurs. |handle| will receive the handle value if |dir| is watchable,
- // otherwise INVALID_HANDLE_VALUE.
- static bool SetupWatchHandle(const FilePath& dir, HANDLE* handle)
- WARN_UNUSED_RESULT;
-
- // (Re-)Initialize the watch handle.
- bool UpdateWatch() WARN_UNUSED_RESULT;
-
- // Destroy the watch handle.
- void DestroyWatch();
-
- // Delegate to notify upon changes.
- scoped_refptr<FilePathWatcher::Delegate> delegate_;
-
- // Path we're supposed to watch (passed to delegate).
- FilePath target_;
-
- // Handle for FindFirstChangeNotification.
- HANDLE handle_;
-
- // ObjectWatcher to watch handle_ for events.
- base::ObjectWatcher watcher_;
-
- // Keep track of the last modified time of the file. We use nulltime
- // to represent the file not existing.
- base::Time last_modified_;
-
- // The time at which we processed the first notification with the
- // |last_modified_| time stamp.
- base::Time first_notification_;
-
- DISALLOW_COPY_AND_ASSIGN(FilePathWatcherImpl);
-};
-
-bool FilePathWatcherImpl::Watch(const FilePath& path,
- FilePathWatcher::Delegate* delegate) {
- DCHECK(target_.value().empty()); // Can only watch one path.
- delegate_ = delegate;
- target_ = path;
-
- if (!UpdateWatch())
- return false;
-
- watcher_.StartWatching(handle_, this);
-
- return true;
-}
-
-void FilePathWatcherImpl::OnObjectSignaled(HANDLE object) {
- DCHECK(object == handle_);
- // Make sure we stay alive through the body of this function.
- scoped_refptr<FilePathWatcherImpl> keep_alive(this);
-
- if (!UpdateWatch()) {
- delegate_->OnError();
- return;
- }
-
- // Check whether the event applies to |target_| and notify the delegate.
- file_util::FileInfo file_info;
- bool file_exists = file_util::GetFileInfo(target_, &file_info);
- if (file_exists && (last_modified_.is_null() ||
- last_modified_ != file_info.last_modified)) {
- last_modified_ = file_info.last_modified;
- first_notification_ = base::Time::Now();
- delegate_->OnFilePathChanged(target_);
- } else if (file_exists && !first_notification_.is_null()) {
- // The target's last modification time is equal to what's on record. This
- // means that either an unrelated event occurred, or the target changed
- // again (file modification times only have a resolution of 1s). Comparing
- // file modification times against the wall clock is not reliable to find
- // out whether the change is recent, since this code might just run too
- // late. Moreover, there's no guarantee that file modification time and wall
- // clock times come from the same source.
- //
- // Instead, the time at which the first notification carrying the current
- // |last_notified_| time stamp is recorded. Later notifications that find
- // the same file modification time only need to be forwarded until wall
- // clock has advanced one second from the initial notification. After that
- // interval, client code is guaranteed to having seen the current revision
- // of the file.
- if (base::Time::Now() - first_notification_ >
- base::TimeDelta::FromSeconds(1)) {
- // Stop further notifications for this |last_modification_| time stamp.
- first_notification_ = base::Time();
- }
- delegate_->OnFilePathChanged(target_);
- } else if (!file_exists && !last_modified_.is_null()) {
- last_modified_ = base::Time();
- delegate_->OnFilePathChanged(target_);
- }
-
- watcher_.StartWatching(handle_, this);
-}
-
-FilePathWatcherImpl::~FilePathWatcherImpl() {
- if (handle_ != INVALID_HANDLE_VALUE)
- DestroyWatch();
-}
-
-// static
-bool FilePathWatcherImpl::SetupWatchHandle(const FilePath& dir,
- HANDLE* handle) {
- *handle = FindFirstChangeNotification(
- dir.value().c_str(),
- false, // Don't watch subtrees
- FILE_NOTIFY_CHANGE_FILE_NAME | FILE_NOTIFY_CHANGE_SIZE |
- FILE_NOTIFY_CHANGE_LAST_WRITE | FILE_NOTIFY_CHANGE_DIR_NAME |
- FILE_NOTIFY_CHANGE_ATTRIBUTES | FILE_NOTIFY_CHANGE_SECURITY);
- if (*handle != INVALID_HANDLE_VALUE) {
- // Make sure the handle we got points to an existing directory. It seems
- // that windows sometimes hands out watches to direectories that are
- // about to go away, but doesn't sent notifications if that happens.
- if (!file_util::DirectoryExists(dir)) {
- FindCloseChangeNotification(*handle);
- *handle = INVALID_HANDLE_VALUE;
- }
- return true;
- }
-
- // If FindFirstChangeNotification failed because the target directory
- // doesn't exist, access is denied (happens if the file is already gone but
- // there are still handles open), or the target is not a directory, try the
- // immediate parent directory instead.
- DWORD error_code = GetLastError();
- if (error_code != ERROR_FILE_NOT_FOUND &&
- error_code != ERROR_PATH_NOT_FOUND &&
- error_code != ERROR_ACCESS_DENIED &&
- error_code != ERROR_DIRECTORY) {
- PLOG(ERROR) << "FindFirstChangeNotification failed for "
- << dir.value();
- return false;
- }
-
- return true;
-}
-
-bool FilePathWatcherImpl::UpdateWatch() {
- if (handle_ != INVALID_HANDLE_VALUE)
- DestroyWatch();
-
- file_util::FileInfo file_info;
- if (file_util::GetFileInfo(target_, &file_info)) {
- last_modified_ = file_info.last_modified;
- first_notification_ = base::Time::Now();
- }
-
- // Start at the target and walk up the directory chain until we succesfully
- // create a watch handle in |handle_|. |child_dirs| keeps a stack of child
- // directories stripped from target, in reverse order.
- std::vector<FilePath> child_dirs;
- FilePath watched_path(target_);
- while (true) {
- if (!SetupWatchHandle(watched_path, &handle_))
- return false;
-
- // Break if a valid handle is returned. Try the parent directory otherwise.
- if (handle_ != INVALID_HANDLE_VALUE)
- break;
-
- // Abort if we hit the root directory.
- child_dirs.push_back(watched_path.BaseName());
- FilePath parent(watched_path.DirName());
- if (parent == watched_path) {
- LOG(ERROR) << "Reached the root directory";
- return false;
- }
- watched_path = parent;
- }
-
- // At this point, handle_ is valid. However, the bottom-up search that the
- // above code performs races against directory creation. So try to walk back
- // down and see whether any children appeared in the mean time.
- while (!child_dirs.empty()) {
- watched_path = watched_path.Append(child_dirs.back());
- child_dirs.pop_back();
- HANDLE temp_handle = INVALID_HANDLE_VALUE;
- if (!SetupWatchHandle(watched_path, &temp_handle))
- return false;
- if (temp_handle == INVALID_HANDLE_VALUE)
- break;
- FindCloseChangeNotification(handle_);
- handle_ = temp_handle;
- }
-
- return true;
-}
-
-void FilePathWatcherImpl::DestroyWatch() {
- watcher_.StopWatching();
- FindCloseChangeNotification(handle_);
- handle_ = INVALID_HANDLE_VALUE;
-}
-
-} // namespace
-
-FilePathWatcher::FilePathWatcher() {
- impl_ = new FilePathWatcherImpl();
-}