Add support for persistent file access in apps.

chrome/browser/extensions/api/file_system/saved_files_service.h

Index: chrome/browser/extensions/api/file_system/saved_files_service.h
diff --git a/chrome/browser/extensions/api/file_system/saved_files_service.h b/chrome/browser/extensions/api/file_system/saved_files_service.h
new file mode 100644
index 0000000000000000000000000000000000000000..823b8529ccfe06e5beedac7037fcef1d50b913c5
--- /dev/null
+++ b/chrome/browser/extensions/api/file_system/saved_files_service.h
@@ -0,0 +1,100 @@
+// Copyright (c) 2013 The Chromium Authors. All rights reserved.

[benwells, 2013/05/16 06:50:17]

Super nit: no (c)

[Matt Giuca, 2013/05/16 07:20:06]

Meta-nit: This is a tiny nit, not a super nit.

[Sam McNally, 2013/05/17 03:38:52]

Done.

+// Use of this source code is governed by a BSD-style license that can be
+// found in the LICENSE file.
+
+#ifndef CHROME_BROWSER_EXTENSIONS_API_FILE_SYSTEM_SAVED_FILES_SERVICE_H_
+#define CHROME_BROWSER_EXTENSIONS_API_FILE_SYSTEM_SAVED_FILES_SERVICE_H_
+
+#include <map>
+#include <set>
+#include <string>
+#include <vector>
+#include "base/files/file_path.h"

[benwells, 2013/05/16 06:50:17]

Nit: blank line between <> includes and others

[Sam McNally, 2013/05/17 03:38:52]

Done.

+#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 extensions {

[benwells, 2013/05/16 06:50:17]

I'm thinking this should be in the apps folder / namespace as it is kind of
shared by a variety of apis.

[Sam McNally, 2013/05/17 03:38:52]

Done.

+
+// Represents a file entry that a user has given an extension permission to
+// access. Intended to be persisted to disk (in the Preferences file), so should
+// remain serializable.
+struct SavedFileEntry {
+  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;
+  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 AddFileEntry(const std::string& extension_id,

[benwells, 2013/05/16 06:50:17]

Nit: I assume this maps to retainFileEntry, can we make its name something like
RetainFileEntry?

[Sam McNally, 2013/05/17 03:38:52]

Done.

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

[benwells, 2013/05/16 06:50:17]

Nit: IsRetained?

[Sam McNally, 2013/05/17 03:38:52]

Done.

+
+  bool GetFileEntry(const std::string& extension_id,
+                    const std::string& id,
+                    SavedFileEntry* out);
+
+  void GetFileEntries(const std::string& extension_id,

[benwells, 2013/05/16 06:50:17]

Why not return the vector?

Nit: GetAllFileEntries

[Sam McNally, 2013/05/17 03:38:52]

Done.

+                      std::vector<SavedFileEntry>* out);
+
+  void ClearExtensionForTest(const std::string& extension_id);
+
+ 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);
+};
+
+void SetMaxSequenceNumberForTest(int max_value);

[benwells, 2013/05/16 06:50:17]

Nit: Please make these static methods on the service.

[Sam McNally, 2013/05/17 03:38:52]

Done.

+void ClearMaxSequenceNumberForTest();
+void SetLruSizeForTest(int size);
+void ClearLruSizeForTest();
+
+}  // namespace extensions
+
+#endif  // CHROME_BROWSER_EXTENSIONS_API_FILE_SYSTEM_SAVED_FILES_SERVICE_H_