Add wrappers around getxattr() and setxattr().

util/mac/xattr.h

+// Copyright 2014 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_UTIL_MAC_XATTR_H_
+#define CRASHPAD_UTIL_MAC_XATTR_H_
+
+#include <time.h>
+
+#include <string>
+
+#include "base/files/file_path.h"
+#include "base/strings/string_piece.h"
+
+namespace crashpad {
+
+//! \brief Reads an extended attribute on a file.
+//!
+//! \param[in] file The path to the file.
+//! \param[in] name The name of the extended attribute to read.
+//! \param[out] value The value of the attribute.
+//!
+//! \return `true` if the read was successful, with \a value filled in. `false`
+//!     on error, with a message logged.
+bool ReadXattr(const base::FilePath& file,
+               const base::StringPiece& name,
+               std::string* value);
+
+//! \brief Writes an extended attribute on a file.
+//!
+//! \param[in] file The path to the file.
+//! \param[in] name The name of the extended attribute to write.
+//! \param[in] value The value of the attribute.
+//!
+//! \return `true` if the write was successful. `false` on error, with a message
+//!     logged.
+bool WriteXattr(const base::FilePath& file,
+                const base::StringPiece& name,
+                const std::string& value);
+
+//! \copydoc ReadXattr
+//!
+//! Only the values `"0"` and `"1"`, for `false` and `true` respectively, are
+//! valid conversions.
+bool ReadXattrBool(const base::FilePath& file,
+                   const base::StringPiece& name,
+                   bool* value);
+
+//! \copydoc WriteXattr
+bool WriteXattrBool(const base::FilePath& file,
+                    const base::StringPiece& name,
+                    bool value);
+
+//! \copydoc ReadXattr
+bool ReadXattrInt(const base::FilePath& file,
+                  const base::StringPiece& name,
+                  int* value);
+
+//! \copydoc WriteXattr
+bool WriteXattrInt(const base::FilePath& file,
+                   const base::StringPiece& name,
+                   int value);
+
+//! \copydoc ReadXattr
+bool ReadXattrTimeT(const base::FilePath& file,
+                    const base::StringPiece& name,
+                    time_t* value);
+
+//! \copydoc WriteXattr
+bool WriteXattrTimeT(const base::FilePath& file,
+                     const base::StringPiece& name,
+                     time_t value);
+
+}  // namespace crashpad
+
+#endif  // CRASHPAD_UTIL_MAC_XATTR_H_