[fsp] Add support for observing entries and notifying about changes.

chrome/browser/chromeos/file_system_provider/fake_provided_file_system.h

 // Copyright 2014 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_SYSTEM_PROVIDER_FAKE_PROVIDED_FILE_SYSTEM_H_
 #define CHROME_BROWSER_CHROMEOS_FILE_SYSTEM_PROVIDER_FAKE_PROVIDED_FILE_SYSTEM_H_
 
 #include <map>
 #include <string>
 #include <vector>
 
 #include "base/callback.h"
 #include "base/memory/linked_ptr.h"
 #include "base/memory/weak_ptr.h"
+#include "base/observer_list.h"
 #include "base/task/cancelable_task_tracker.h"
 #include "chrome/browser/chromeos/file_system_provider/provided_file_system_info.h"
 #include "chrome/browser/chromeos/file_system_provider/provided_file_system_interface.h"
+#include "chrome/browser/chromeos/file_system_provider/provided_file_system_observer.h"
 
 class Profile;
 
 namespace base {
 class Time;
 }  // namespace base
 
 namespace net {
 class IOBuffer;
 }  // namespace net
@@ skipping 87 matching lines @@
   virtual AbortCallback Truncate(
       const base::FilePath& file_path,
       int64 length,
       const storage::AsyncFileUtil::StatusCallback& callback) OVERRIDE;
   virtual AbortCallback WriteFile(
       int file_handle,
       net::IOBuffer* buffer,
       int64 offset,
       int length,
       const storage::AsyncFileUtil::StatusCallback& callback) OVERRIDE;
+  virtual AbortCallback ObserveDirectory(

[mtomasz, 2014/10/03 04:22:47]

Currently we support observing directories only, never single files, but it will
be added as ObserveFile in the future.

I want to separate these two methods, since |recursive| doesn't make sense for
files, but only for directories.

+      const base::FilePath& directory_path,
+      bool recursive,
+      const storage::AsyncFileUtil::StatusCallback& callback) OVERRIDE;
+  virtual AbortCallback UnobserveEntry(

[mtomasz, 2014/10/03 04:22:47]

Method for unobserving files would have the same signature, hence there will be
only one method UnobserveEntry which will unobserve both directories and files.

+      const base::FilePath& entry_path,
+      const storage::AsyncFileUtil::StatusCallback& callback) OVERRIDE;
   virtual const ProvidedFileSystemInfo& GetFileSystemInfo() const OVERRIDE;
   virtual RequestManager* GetRequestManager() OVERRIDE;
+  virtual ObservedEntries* GetObservedEntries() OVERRIDE;
+  virtual void AddObserver(ProvidedFileSystemObserver* observer) OVERRIDE;

[mtomasz, 2014/10/03 04:22:47]

Cache implementation will add itself as an observer. So it will be able to
invalidate entries which are changed remotely.

+  virtual void RemoveObserver(ProvidedFileSystemObserver* observer) OVERRIDE;
+  virtual bool Notify(

[mtomasz, 2014/10/03 04:22:47]

This is called from file_system_provider_api.cc, so by providing extensions.
This method simply updates the tag in the internal collection of observed
entries, and notifies observers.

+      const base::FilePath& observed_path,
+      ProvidedFileSystemObserver::ChangeType change_type,
+      const ProvidedFileSystemObserver::ChildChanges& child_changes,
+      const std::string& tag) OVERRIDE;
   virtual base::WeakPtr<ProvidedFileSystemInterface> GetWeakPtr() OVERRIDE;
 
   // Factory callback, to be used in Service::SetFileSystemFactory(). The
   // |event_router| argument can be NULL.
   static ProvidedFileSystemInterface* Create(
       Profile* profile,
       const ProvidedFileSystemInfo& file_system_info);
 
  private:
   typedef std::map<base::FilePath, linked_ptr<FakeEntry> > Entries;
@@ skipping 12 matching lines @@
   // returning a response for the operation, which will be cancelled, hence not
   // called.
   void AbortMany(const std::vector<int>& task_ids,
                  const storage::AsyncFileUtil::StatusCallback& callback);
 
   ProvidedFileSystemInfo file_system_info_;
   Entries entries_;
   OpenedFilesMap opened_files_;
   int last_file_handle_;
   base::CancelableTaskTracker tracker_;
+  ObserverList<ProvidedFileSystemObserver> observers_;
 
   base::WeakPtrFactory<FakeProvidedFileSystem> weak_ptr_factory_;
   DISALLOW_COPY_AND_ASSIGN(FakeProvidedFileSystem);
 };
 
 }  // namespace file_system_provider
 }  // namespace chromeos
 
 #endif  // CHROME_BROWSER_CHROMEOS_FILE_SYSTEM_PROVIDER_FAKE_PROVIDED_FILE_SYSTEM_H_