The chrome.lockScreen.data API implementation

extensions/browser/api/lock_screen_data/data_item.h

+// Copyright 2017 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 EXTENSIONS_BROWSER_API_LOCK_SCREEN_DATA_DATA_ITEM_H_
+#define EXTENSIONS_BROWSER_API_LOCK_SCREEN_DATA_DATA_ITEM_H_
+
+#include <memory>
+#include <string>
+#include <vector>
+
+#include "base/callback.h"
+#include "base/memory/ref_counted.h"
+#include "base/memory/weak_ptr.h"
+
+namespace content {
+class BrowserContext;
+}
+
+namespace base {
+class DictionaryValue;
+class SequencedTaskRunner;
+}  // namespace base
+
+namespace extensions {
+
+class ValueStoreCache;
+
+namespace lock_screen_data {
+
+enum class OperationResult;
+
+// Wrapper around a per extension value store backed lock screen data item.
+class DataItem {
+ public:
+  using WriteCallback = base::Callback<void(OperationResult result)>;
+  using ReadCallback =
+      base::Callback<void(OperationResult result,
+                          std::unique_ptr<std::vector<char>> data)>;
+  using RegisteredValuesCallback =
+      base::Callback<void(OperationResult result,
+                          std::unique_ptr<base::DictionaryValue> values)>;
+
+  // Gets all registered data items for the extension with the provided
+  // extension ID - the items are returned as a DictionaryValue with keys set
+  // to data item IDs.
+  static void GetRegisteredValuesForExtension(
+      content::BrowserContext* context,
+      ValueStoreCache* value_store_cache,
+      base::SequencedTaskRunner* task_runner,
+      const std::string& extension_id,
+      const RegisteredValuesCallback& callback);
+
+  // Clears data item value store for the extension with the provided extension
+  // ID.
+  static void DeleteAllItemsForExtension(content::BrowserContext* context,
+                                         ValueStoreCache* value_store_cache,
+                                         base::SequencedTaskRunner* task_runner,
+                                         const std::string& extension_id,
+                                         const base::Closure& callback);
+
+  // |id| - Data item ID.
+  // |extension_id| - The extension that owns the item.
+  // |context| - The browser context to which the owning extension is attached.
+  // |value_store_cache| - Used to retrieve value store for the extension with
+  //     |extension_id| ID. Not owned - the caller should ensure the value store
+  //     cache outlives the data item. Note that DataItem post tasks with
+  //     unretained |value_store_cache| to |task_runner|, which means any usage
+  //     of DataItem should happen before value store cache deletion is
+  ///    scheduled to |task_runner|.
+  // |task_runner| - The task runner on which value store should be used. Note
+  //     that the Data item does not retain a reference to the task runner -
+  //     the caller should ensure |task_runner| outlives the data item.
+  // |crypto_key| - Symmetric AES key for encrypting/decrypting data item
+  //     content.
+  DataItem(const std::string& id,
+           const std::string& extension_id,
+           content::BrowserContext* context,
+           ValueStoreCache* value_store_cache,
+           base::SequencedTaskRunner* task_runner,
+           const std::string& crypto_key);
+  virtual ~DataItem();
+
+  // Registers the data item in the persistent data item storage.
+  virtual void Register(const WriteCallback& callback);
+
+  // Sets the data item content, saving it to persistent data storage.
+  // This will fail if the data item is not registered.
+  virtual void Write(const std::vector<char>& data,
+                     const WriteCallback& callback);
+
+  // Gets the data item content from the persistent data storage.
+  // This will fail is the item is not registered.
+  virtual void Read(const ReadCallback& callback);
+
+  // Unregisters the data item, and clears previously persisted data item
+  // content.
+  virtual void Delete(const WriteCallback& callback);
+
+  const std::string& id() const { return id_; }
+
+  const std::string& extension_id() const { return extension_id_; }
+
+ private:
+  // Internal callback for write operations - wraps |callback| to ensure
+  // |callback| is not run after |this| has been destroyed.
+  void OnWriteDone(const WriteCallback& callback,
+                   std::unique_ptr<OperationResult> result);
+
+  // Internal callback for the read operation - wraps |callback| to ensure
+  // |callback| is not run after |this| has been destroyed.
+  void OnReadDone(const ReadCallback& callback,
+                  std::unique_ptr<OperationResult> result,
+                  std::unique_ptr<std::vector<char>> data);
+
+  // The data item ID.
+  std::string id_;
+
+  // The ID of the extension that owns the data item.
+  std::string extension_id_;
+
+  content::BrowserContext* context_;
+
+  // Cache used to retrieve the values store to which the data item should be
+  // saved - the value stores are mapped by the extension ID.
+  ValueStoreCache* value_store_cache_;
+
+  // Task runner on which value store should be accessed.
+  base::SequencedTaskRunner* task_runner_;
+
+  // They symmetric AES key that should be used to encrypt data item content
+  // when the content is written to the storage, and to decrypt item content
+  // when reading it from the storage.
+  const std::string crypto_key_;
+
+  base::WeakPtrFactory<DataItem> weak_ptr_factory_;
+
+  DISALLOW_COPY_AND_ASSIGN(DataItem);
+};
+
+}  // namespace lock_screen_data
+}  // namespace extensions
+
+#endif  // EXTENSIONS_BROWSER_API_LOCK_SCREEN_DATA_DATA_ITEM_H_