[Offline pages] Adding persistent request queue based on SQLite

components/offline_pages/background/request_queue_store_sql.h

Index: components/offline_pages/background/request_queue_store_sql.h
diff --git a/components/offline_pages/background/request_queue_store_sql.h b/components/offline_pages/background/request_queue_store_sql.h
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+++ b/components/offline_pages/background/request_queue_store_sql.h
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+// Copyright 2016 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 COMPONENTS_OFFLINE_PAGES_BACKGROUND_REQUEST_QUEUE_STORE_SQL_H_
+#define COMPONENTS_OFFLINE_PAGES_BACKGROUND_REQUEST_QUEUE_STORE_SQL_H_
+
+#include <stdint.h>
+
+#include <memory>
+#include <vector>
+
+#include "base/files/file_path.h"
+#include "base/memory/weak_ptr.h"
+#include "components/offline_pages/background/request_queue_store.h"
+
+namespace base {
+class SequencedTaskRunner;
+}
+
+namespace sql {
+class Connection;
+}
+
+namespace offline_pages {
+
+// SQLite implementation of RequestQueueStore.
+class RequestQueueStoreSQL : public RequestQueueStore {
+ public:
+  RequestQueueStoreSQL(
+      scoped_refptr<base::SequencedTaskRunner> background_task_runner,
+      const base::FilePath& database_dir);
+  ~RequestQueueStoreSQL() override;
+
+  // RequestQueueStore implementation.
+  void GetRequests(const GetRequestsCallback& callback) override;
+  void AddOrUpdateRequest(const SavePageRequest& offline_page,
+                          const UpdateCallback& callback) override;
+  void RemoveRequests(const std::vector<int64_t>& request_ids,
+                      const RemoveCallback& callback) override;
+  void Reset(const ResetCallback& callback) override;
+
+ private:
+  // Synchronous implementations, these are run on the background thread
+  // and actually do the work to access SQL.  The implementations above
+  // simply dispatch to the corresponding *Sync method on the background thread.
+  // 'runner' is where to run the callback.
+  static void GetRequestsSync(
+      sql::Connection* db,
+      scoped_refptr<base::SingleThreadTaskRunner> runner,
+      const GetRequestsCallback& callback);
+  static void AddOrUpdateRequestSync(
+      sql::Connection* db,
+      scoped_refptr<base::SingleThreadTaskRunner> runner,
+      const SavePageRequest& offline_page,
+      const UpdateCallback& callback);
+  static void RemoveRequestsSync(
+      sql::Connection* db,
+      scoped_refptr<base::SingleThreadTaskRunner> runner,
+      const std::vector<int64_t>& request_ids,
+      const RemoveCallback& callback);
+  static void ResetSync(sql::Connection* db,
+                        const base::FilePath& db_file_path,
+                        scoped_refptr<base::SingleThreadTaskRunner> runner,
+                        const ResetCallback& callback);
+
+  // Used to initialize DB connection.
+  static void OpenConnectionSync(
+      sql::Connection* db,
+      scoped_refptr<base::SingleThreadTaskRunner> runner,
+      const base::FilePath& path,
+      const base::Callback<void(bool)>& callback);
+  void OpenConnection();
+  void OnOpenConnectionDone(bool success);
+
+  // Used to finalize connection reset.
+  void OnResetDone(const ResetCallback& callback, bool success);
+
+  // Background thread where all SQL access should be run.
+  scoped_refptr<base::SequencedTaskRunner> background_task_runner_;
+
+  // Path to the database on disk.
+  base::FilePath db_file_path_;
+
+  // Database connection.
+  std::unique_ptr<sql::Connection> db_;
+
+  base::WeakPtrFactory<RequestQueueStoreSQL> weak_ptr_factory_;
+  DISALLOW_COPY_AND_ASSIGN(RequestQueueStoreSQL);
+};
+
+}  // namespace offline_pages
+
+#endif  // COMPONENTS_OFFLINE_PAGES_BACKGROUND_REQUEST_QUEUE_STORE_SQL_H_