Google OAuth Device Flow support for FNL

services/authentication/accounts_db_manager.h

+// 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 SERVICES_AUTHENTICATION_ACCOUNTS_DB_MANAGER_H_
+#define SERVICES_AUTHENTICATION_ACCOUNTS_DB_MANAGER_H_
+
+#include <type_traits>
+
+#include "base/macros.h"
+#include "mojo/services/files/interfaces/files.mojom.h"
+#include "services/authentication/authentication_impl_db.mojom.h"
+#include "services/authentication/credentials_impl_db.mojom.h"
+
+namespace authentication {
+
+// Implementation of user account management service on systems like FNL. This
+// uses native mojo files service as the underlying mechanism to store user
+// credentials and supports operations such as to add a new user account, update
+// existing user credentials and fetching current credentials for a given user.
+class AccountsDbManager {
+ public:
+  // Constructor that takes a directory handle to create or open existing auth
+  // and credentials db files. It also initializes the in-memory cache with the
+  // file contents from the disk.
+  AccountsDbManager(const mojo::files::DirectoryPtr directory);
+  ~AccountsDbManager();
+  // Returns true, if there are no errors during Db initialization or commits.
+  bool isValid();
+  // Fetches auth credentials for a given user account.
+  authentication::CredentialsPtr GetCredentials(const mojo::String& username);
+  // Returns a list of all users registered on the device.
+  mojo::Array<mojo::String> GetAllUsers();
+  // Updates or adds new auth credentials for a given user account.
+  void UpdateCredentials(const mojo::String& username,
+                         const authentication::CredentialsPtr creds);
+  // Returns previously used account name for the given application or null if
+  // not found.
+  mojo::String GetAuthorizedUserForApp(mojo::String app_url);
+  // Updates the grants database for the given application and username.
+  void UpdateAuthorization(mojo::String app_url, mojo::String username);
+
+ private:
+  // DB Init Options for tracking the init state of in-memory contents.
+  enum DBInitOptions {
+    // Default init state.
+    START_INIT = 0x01,
+    // Credentials db in-memory content is populated successfully.
+    CREDENTIALS_DB_INIT_SUCCESS = 0x02,
+    // Authorizations db in-memory content is populated successfully.
+    AUTHORIZATIONS_DB_INIT_SUCCESS = 0x04
+  };
+
+  // Errors for tracking the lifecycle of AccountsDbManager object.
+  enum Error {
+    NONE = 1,
+    // File read error on credentials db.
+    CREDENTIALS_DB_READ_ERROR,
+    // File write error on credentials db.
+    CREDENTIALS_DB_WRITE_ERROR,
+    // File validate error on credentials db.
+    CREDENTIALS_DB_VALIDATE_ERROR,
+    // File read error on authorizations db.
+    AUTHORIZATIONS_DB_READ_ERROR,
+    // File write error on authorizations db.
+    AUTHORIZATIONS_DB_WRITE_ERROR,
+    // File validate error on authorizations db.
+    AUTHORIZATIONS_DB_VALIDATE_ERROR
+  };
+
+  // Populates contents with existing user credentials.
+  void Initialize();
+  // Reads from credentials file and populates in-memory contents cache.
+  void OnCredentialsFileReadResponse(const mojo::files::Error error,
+                                     const mojo::Array<uint8_t> bytes_read);
+  // Parses response from credentials file write operation
+  void OnCredentialsFileWriteResponse(const mojo::files::Error error,
+                                      const uint32_t num_bytes_written);
+  // Reads from auth file and populates in-memory grants cache.
+  void OnAuthorizationsFileReadResponse(const mojo::files::Error error,
+                                        const mojo::Array<uint8_t> bytes_read);
+  // Parses response from auth file write operation
+  void OnAuthorizationsFileWriteResponse(const mojo::files::Error error,
+                                         const uint32_t num_bytes_written);
+  // Waits for the credentials db file handle to finish the blocking read
+  // operation as part of initialization, before proceeding further.
+  void ensureCredentialsDbInit();
+  // Waits for the authorizations db file handle to finish the blocking read
+  // operation as part of initialization, before proceeding further.
+  void ensureAuthorizationsDbInit();
+
+  // File pointer to the stored account credentials db file.
+  mojo::files::FilePtr creds_db_file_;
+  // File pointer to the list of authorized modules.
+  mojo::files::FilePtr auth_db_file_;
+  // In-memory store for credential data for all users.
+  authentication::CredentialStore creds_store_;
+  // In-memory store for list of authorized apps.
+  authentication::Db auth_grants_;
+  // Flag to track in-memory contents init state.
+  unsigned char db_init_option_ = START_INIT;
+  // Flag to track the current error status.
+  Error error_ = NONE;
+
+  DISALLOW_COPY_AND_ASSIGN(AccountsDbManager);
+};
+
+}  // namespace authentication
+
+#endif  // SERVICES_AUTHENTICATION_ACCOUNTS_DB_MANAGER_H_