Define the Settings interface for a CrashReportDatabase and provide a Mac implementation.

client/settings.h

+// Copyright 2015 The Crashpad Authors. All rights reserved.
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//     http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+#ifndef CRASHPAD_CLIENT_SETTINGS_H_
+#define CRASHPAD_CLIENT_SETTINGS_H_
+
+#include <time.h>
+
+#include <string>
+
+#include "base/basictypes.h"
+#include "base/files/file_path.h"
+#include "util/file/file_io.h"
+#include "util/misc/uuid.h"
+
+namespace crashpad {
+
+//! \brief An interface for accessing and modifying the settings of a
+//!     CrashReportDatabase.
+//!
+//! This class cannot be instantiated directly, but rather an instance of it

[Mark Mentovai, 2015/03/09 19:12:36]

“cannot” makes it sound like it’s physically impossible, but that’s not the case
(the constructor is public). Instead, say “must not”.

[Robert Sesek, 2015/03/09 21:16:27]

Done.

+//! should be retrieved via CrashReportDatabase::GetSettings().
+class Settings {
+ public:
+  explicit Settings(const base::FilePath& file_path);
+  ~Settings();
+
+  bool Initialize();
+
+  //! \brief Retrieves the immutable identifier for this client, which is used
+  //!     to locate all crash reports from a specific Crashpad database.

[Mark Mentovai, 2015/03/09 19:12:36]

used on a server

[Robert Sesek, 2015/03/09 21:16:27]

Done.

+  //!
+  //! This is automatically initialized when the database is created.
+  //!
+  //! \param[out] client_id The unique client identifier.
+  //!
+  //! \return On success, returns `true`, otherwise returns `false` with an
+  //!     error logged.
+  bool GetClientID(UUID* client_id);
+
+  //! \brief Retrieves the user’s preference for submitting crash reports to a
+  //!     collection server.
+  //!
+  //! The default value is `false`.
+  //!
+  //! \param[out] enabled Whether crash reports should be uploaded.
+  //!
+  //! \return On success, returns `true`, otherwise returns `false` with an
+  //!     error logged.
+  bool GetUploadsEnabled(bool* enabled);
+
+  //! \brief Sets the user’s preference for submitting crash reports to a
+  //!     collection server.
+  //!
+  //! \param[in] enabled Whether crash reports should be uploaded.
+  //!
+  //! \return On success, returns `true`, otherwise returns `false` with an
+  //!     error logged.
+  bool SetUploadsEnabled(bool enabled);
+
+  //! \brief Retrieves the last time at which a report was attempted to be
+  //!     uploaded.
+  //!
+  //! The default value is `0` if it has never been set before.
+  //!
+  //! \param[out] time The last time at which a report was uploaded.
+  //!
+  //! \return On success, returns `true`, otherwise returns `false` with an
+  //!     error logged.
+  bool GetLastUploadAttemptTime(time_t* time);
+
+  //! \brief Sets the last time at which a report was attempted to be uploaded.
+  //!
+  //! This is only meant to be used internally by the CrashReportDatabase.
+  //!
+  //! \param[in] time The last time at which a report was uploaded.
+  //!
+  //! \return On success, returns `true`, otherwise returns `false` with an
+  //!     error logged.
+  bool SetLastUploadAttemptTime(time_t time);
+
+ private:
+  struct Data;
+
+  // Opens the settings file for reading. On error, logs a message and returns
+  // the invalid handle.
+  ScopedFileHandle OpenForReading();
+
+  // Opens the settings file for writing. On error, logs a message and returns
+  // the invalid handle.
+  ScopedFileHandle OpenForWriting();

[Mark Mentovai, 2015/03/09 19:12:36]

OpenForReadingAndWriting(), and adjust the comment accordingly.

[Robert Sesek, 2015/03/09 21:16:27]

Done.

+
+  // Opens the settings file and reads the data. If that fails, an error will
+  // be logged and the settings will be recovered and re-initialized. If that
+  // fails, returns false.

[Mark Mentovai, 2015/03/09 19:12:36]

Add the word “also” before the final “fails.” Also say that it logs more stuff
if recovery fails.

[Robert Sesek, 2015/03/09 21:16:27]

Done.

+  bool OpenAndReadSettings(Data* out_data);
+
+  // Reads the settings from |handle|. Logs an error and returns false on
+  // failure. This does not perform recovery.
+  bool ReadSettings(FileHandle handle, Data* out_data);
+
+  // Writes the settings to |handle|. Logs an error and returns false on
+  // failure. This does not perform recovery.
+  bool WriteSettings(FileHandle handle, const Data* data);

[Mark Mentovai, 2015/03/09 19:12:36]

const Data& instead of const Data* for the const in-parameter that is required.
Looks like that works well at all call sites.

[Robert Sesek, 2015/03/09 21:16:27]

Done.

+
+  // Recovers the settings file by re-initializing the data. If |handle| is the
+  // invalid handle, this will open the file; if it is not, then it must be the
+  // result of OpenForWriting(). The new settings data are stored in |out_data|.

[Mark Mentovai, 2015/03/09 19:12:36]

Also say that the caller must not be holding a handle if it passes in an invalid
handle for this argument.

[Robert Sesek, 2015/03/09 21:16:27]

Done.

+  // Returns true on success and false on failure, with an error logged.
+  bool RecoverSettings(FileHandle handle, Data* out_data);
+
+  // Initializes a settings file and writes the data to |handle|. Returns true
+  // on success and false on failure, with an error logged.
+  bool InitializeSettings(FileHandle handle);
+
+  const char* file_path() { return file_path_.value().c_str(); }
+
+  base::FilePath file_path_;
+
+  DISALLOW_COPY_AND_ASSIGN(Settings);
+};
+
+}  // namespace crashpad
+
+#endif  // CRASHPAD_CLIENT_SETTINGS_H_