contacts: Add contacts::ContactDatabase.

chrome/browser/chromeos/contacts/contact_database.h

+// Copyright (c) 2012 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_CONTACTS_CONTACT_DATABASE_H_
+#define CHROME_BROWSER_CHROMEOS_CONTACTS_CONTACT_DATABASE_H_
+
+#include <vector>
+
+#include "base/basictypes.h"
+#include "base/callback.h"
+#include "base/compiler_specific.h"
+#include "base/file_path.h"
+#include "base/memory/ref_counted.h"
+#include "base/memory/scoped_ptr.h"
+#include "base/memory/scoped_vector.h"
+#include "base/memory/weak_ptr.h"
+
+namespace base {
+class SequencedTaskRunner;
+}
+
+namespace leveldb {
+class DB;
+}
+
+namespace contacts {
+
+class Contact;
+typedef std::vector<const Contact*> ContactPointers;
+
+// Interface for classes providing persistent storage of Contact objects.
+class ContactDatabaseInterface {
+ public:
+  typedef base::Callback<void(const bool* success)> InitCallback;

[satorux1, 2012/07/31 19:56:57]

It may be awkward for the client of this class to get a bool pointer, rather
than a bool.

It's a bit tedious but you might want to convert bool* to bool before passing it
to client-supplied callbacks.

[Daniel Erat, 2012/07/31 21:10:56]

Done.

+  typedef base::Callback<void(const bool* success)> SaveCallback;
+  typedef base::Callback<void(const bool* success,
+                              scoped_ptr<ScopedVector<Contact> >)> LoadCallback;
+
+  ContactDatabaseInterface() {}
+
+  // Asynchronously destroys the object after all in-progress file operations
+  // have completed.
+  virtual void DestroyOnUIThread() {}
+
+  // Asynchronously initializes the object.  |callback| will be invoked on the
+  // UI thread when complete.
+  virtual void Init(const FilePath& database_dir, InitCallback callback) = 0;
+
+  // Asynchronously saves |contacts| to the database.  If |is_full_update| is
+  // true, all existing contacts in the database not present in |contacts| will
+  // be removed.  |callback| will be invoked on the UI thread when complete.
+  // The caller must not make changes to the underlying passed-in Contact
+  // objects until the callback has been invoked.
+  virtual void SaveContacts(scoped_ptr<ContactPointers> contacts,
+                            bool is_full_update,
+                            SaveCallback callback) = 0;
+
+  // Asynchronously loads all contacts from the database and invokes |callback|
+  // when complete.
+  virtual void LoadContacts(LoadCallback callback) = 0;
+
+ protected:
+  virtual ~ContactDatabaseInterface() {}
+
+ private:
+  DISALLOW_COPY_AND_ASSIGN(ContactDatabaseInterface);
+};
+
+class ContactDatabase : public ContactDatabaseInterface {
+ public:
+  ContactDatabase();
+
+  // ContactDatabaseInterface implementation.
+  virtual void DestroyOnUIThread() OVERRIDE;
+  virtual void Init(const FilePath& database_dir,
+                    InitCallback callback) OVERRIDE;
+  virtual void SaveContacts(scoped_ptr<ContactPointers> contacts,
+                            bool is_full_update,
+                            SaveCallback callback) OVERRIDE;
+  virtual void LoadContacts(LoadCallback callback) OVERRIDE;
+
+ protected:
+  virtual ~ContactDatabase();
+
+ private:
+  // Are we currently being run by |task_runner_|?
+  bool IsRunByTaskRunner() const;
+
+  // Deletes |this|.
+  void DestroyFromTaskRunner();
+
+  // Runs |closure| after being called on the UI thread.  Used for replies sent
+  // in response to |task_runner_|'s tasks, so that weak_ptrs can be used to
+  // avoid running the replies after the ContactDatabase has been deleted.
+  void RunCallback(base::Closure closure);
+
+  // Initializes the database in |database_dir| and updates |success|.
+  void InitFromTaskRunner(const FilePath& database_dir, bool* success);
+
+  // Saves |contacts| to disk and updates |success|.
+  void SaveContactsFromTaskRunner(scoped_ptr<ContactPointers> contacts,
+                                  bool is_full_update,
+                                  bool* success);
+
+  // Loads contacts from disk and updates |success|.
+  void LoadContactsFromTaskRunner(bool* success,
+                                  ScopedVector<Contact>* contacts_out);
+
+  // Used to run blocking tasks in-order.
+  scoped_refptr<base::SequencedTaskRunner> task_runner_;
+
+  base::WeakPtrFactory<ContactDatabase> weak_ptr_factory_;

[satorux1, 2012/07/31 19:56:57]

This is very subtle but my understanding is that this should be the last member,
so that it's destructed before other members.

[satorux1, 2012/07/31 19:58:03]

This may not matter here as InvalidateWeakPtrs() is manually called, but
usually, it's implicit, and weak pointers have to be invalidated before other
members.

[Daniel Erat, 2012/07/31 21:10:56]

Done.

+
+  scoped_ptr<leveldb::DB> db_;
+
+  DISALLOW_COPY_AND_ASSIGN(ContactDatabase);
+};
+
+}  // namespace contacts
+
+#endif  // CHROME_BROWSER_CHROMEOS_CONTACTS_CONTACT_DATABASE_H_