Add support for persistent file access in apps.

apps/saved_files_service.h

Index: apps/saved_files_service.h
diff --git a/apps/saved_files_service.h b/apps/saved_files_service.h
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+++ b/apps/saved_files_service.h
@@ -0,0 +1,102 @@
+// Copyright 2013 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 APPS_SAVED_FILES_SERVICE_H_
+#define APPS_SAVED_FILES_SERVICE_H_
+
+#include <map>
+#include <set>
+#include <string>
+#include <vector>
+
+#include "base/files/file_path.h"
+#include "base/stl_util.h"
+#include "chrome/browser/profiles/profile_keyed_service.h"
+#include "content/public/browser/notification_observer.h"
+#include "content/public/browser/notification_registrar.h"
+
+class Profile;
+
+namespace apps {
+
+// Represents a file entry that a user has given an extension permission to

[Matt Giuca, 2013/05/17 08:28:45]

s/extension/app

[Sam McNally, 2013/05/20 01:17:13]

Done.

+// access. Intended to be persisted to disk (in the Preferences file), so should
+// remain serializable.
+struct SavedFileEntry {

[Matt Giuca, 2013/05/17 08:28:45]

If it's serializable, how do you serialize it? Shouldn't there be a method for
doing so?

[Sam McNally, 2013/05/20 01:17:13]

See AddSavedFileEntry and friends in saved_files_service.cc.

+  SavedFileEntry()
+      : writable(false),
+        sequence_number(0) {}
+
+  SavedFileEntry(const std::string& id,
+                 const base::FilePath& path,
+                 bool writable,
+                 int sequence_number)
+      : id(id),
+        path(path),
+        writable(writable),
+        sequence_number(sequence_number) {}
+
+  std::string id;

[Matt Giuca, 2013/05/17 08:28:45]

Document (briefly) each of these fields.

[Sam McNally, 2013/05/20 01:17:13]

Done.

+  base::FilePath path;
+  bool writable;
+  int sequence_number;
+};
+
+class SavedFilesService : public ProfileKeyedService,
+                          public content::NotificationObserver {
+ public:
+  explicit SavedFilesService(Profile* profile);
+  virtual ~SavedFilesService();
+
+  static SavedFilesService* Get(Profile* profile);
+
+  void RetainFileEntry(const std::string& extension_id,

[Matt Giuca, 2013/05/17 08:28:45]

Document.

[Sam McNally, 2013/05/20 01:17:13]

Done.

+                       const std::string& id,
+                       const base::FilePath& file_path,
+                       bool writable);
+
+  void MoveEntryToFrontOfQueue(const std::string& extension_id,

[Matt Giuca, 2013/05/17 08:28:45]

Document.

[Sam McNally, 2013/05/20 01:17:13]

Done.

+                               const std::string& id);
+
+  bool IsRetained(const std::string& extension_id, const std::string& id);

[Matt Giuca, 2013/05/17 08:28:45]

Document.

[Sam McNally, 2013/05/20 01:17:13]

Done.

+
+  bool GetFileEntry(const std::string& extension_id,

[Matt Giuca, 2013/05/17 08:28:45]

Document.

[Sam McNally, 2013/05/20 01:17:13]

Done.

+                    const std::string& id,
+                    SavedFileEntry* out);
+
+  std::vector<SavedFileEntry> GetAllFileEntries(

[Matt Giuca, 2013/05/17 08:28:45]

Document.

[Sam McNally, 2013/05/20 01:17:13]

Done.

+      const std::string& extension_id);
+
+  void ClearExtensionForTest(const std::string& extension_id);

[Matt Giuca, 2013/05/17 08:28:45]

Document.

[Sam McNally, 2013/05/20 01:17:13]

Done.

+
+  static void SetMaxSequenceNumberForTest(int max_value);

[Matt Giuca, 2013/05/17 08:28:45]

Document these four, and explain (in a paragraph above) that these should only
be used for testing purposes, and not in production code. I know the name
implies this, but it's always good to document as well.

Or, perhaps better yet, make them private and make the test class a friend.

[Sam McNally, 2013/05/20 01:17:13]

Done.

+  static void ClearMaxSequenceNumberForTest();
+  static void SetLruSizeForTest(int size);
+  static void ClearLruSizeForTest();
+
+ private:
+  class SavedFiles;
+
+  // content::NotificationObserver.
+  virtual void Observe(int type,
+                       const content::NotificationSource& source,
+                       const content::NotificationDetails& details) OVERRIDE;
+
+  SavedFiles* GetOrInsert(const std::string& extension_id);
+
+  void ClearExtension(const std::string& extension_id);
+
+  std::map<std::string, SavedFiles*> extension_id_to_saved_files_;
+  STLValueDeleter<std::map<std::string, SavedFiles*> >
+      extension_id_to_saved_files_deleter_;
+  std::set<std::string> extensions_to_clear_;
+  content::NotificationRegistrar registrar_;
+  Profile* profile_;
+
+  DISALLOW_COPY_AND_ASSIGN(SavedFilesService);
+};
+
+}  // namespace apps
+
+#endif  // APPS_SAVED_FILES_SERVICE_H_