Introduce MinidumpStringWriter and its test

minidump/minidump_writer_util.h

Index: minidump/minidump_writer_util.h
diff --git a/minidump/minidump_writer_util.h b/minidump/minidump_writer_util.h
new file mode 100644
index 0000000000000000000000000000000000000000..deb3648d67717ccc2d10db24310b33c94f49423d
--- /dev/null
+++ b/minidump/minidump_writer_util.h
@@ -0,0 +1,90 @@
+// 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_MINIDUMP_MINIDUMP_WRITER_UTIL_H_
+#define CRASHPAD_MINIDUMP_MINIDUMP_WRITER_UTIL_H_
+
+#include <stdint.h>
+#include <sys/types.h>
+#include <time.h>
+
+#include <string>
+
+#include "base/basictypes.h"
+#include "base/strings/string16.h"
+
+namespace crashpad {
+namespace internal {
+
+//! \brief A collection of utility functions used by the MinidumpWritable family
+//!     of classes.
+class MinidumpWriterUtil final {
+ public:
+  //! \brief Assigns a `time_t` value, logging a warning if the result overflows
+  //!     the destination buffer and will be truncated.
+  //!
+  //! \param[out] destination A pointer to the variable to be assigned to.
+  //! \param[in] source The value to assign.
+  //!
+  //! The minidump format uses `uint32_t` for many timestamp values, but
+  //! `time_t` may be wider than this. These year 2038 bugs are a limitation of
+  //! the minidump format. An out-of-range error will be noted with a warning,
+  //! but is not considered fatal. \a source will be truncated and assigned to
+  //! \a destination in this case.
+  //!
+  //! For `time_t` values with nonfatal overflow semantics, this function is
+  //! used in preference to AssignIfInRange(), which fails without performing an
+  //! assignment when an out-of-range condition is detected.
+  static void AssignTimeT(uint32_t* destination, time_t source);
+
+  //! \brief Converts a UTF-8 string to UTF-16 and returns it. If the string
+  //!     cannot be converted losslessly, indicating that the input is not
+  //!     well-formed UTF-8, a warning is logged.
+  //!
+  //! \param[in] utf8 The UTF-8-encoded string to convert.
+  //!
+  //! \return The \a utf8 string, converted to UTF-16 encoding. If the
+  //!     conversion is lossy, U+FFFD “replacement characters” will be
+  //!     introduced.
+  static string16 ConvertUTF8ToUTF16(const std::string& utf8);
+
+  //! \brief Converts a UTF-8 string to UTF-16 and places it into a buffer of
+  //!     fixed size, taking care to `NUL`-terminate the buffer and not to
+  //!     overflow it. If the string will be truncated or if it cannot be
+  //!     converted losslessly, a warning is logged.
+  //!
+  //! Any unused portion of the \a destination buffer that is not written to by
+  //! the converted string will be overwritten with `NUL` UTF-16 code units,
+  //! thus, this function always writes \a destination_size `char16` units.
+  //!
+  //! If the conversion is lossy, U+FFFD “replacement characters” will be
+  //! introduced.
+  //!
+  //! \param[out] destination A pointer to the destination buffer, where the
+  //!     UTF-16-encoded string will be written.
+  //! \param[in] destination_size The size of \a destination in `char16` units,
+  //!     including space used by a `NUL` terminator.
+  //! \param[in] source The UTF-8-encoded input string.
+  static void AssignUTF8ToUTF16(char16* destination,
+                                size_t destination_size,
+                                const std::string& source);
+
+ private:
+  DISALLOW_IMPLICIT_CONSTRUCTORS(MinidumpWriterUtil);
+};
+
+}  // namespace internal
+}  // namespace crashpad
+
+#endif  // CRASHPAD_MINIDUMP_MINIDUMP_WRITER_UTIL_H_