Introduce MinidumpStringWriter and its test

minidump/minidump_string_writer.cc

Index: minidump/minidump_string_writer.cc
diff --git a/minidump/minidump_string_writer.cc b/minidump/minidump_string_writer.cc
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+++ b/minidump/minidump_string_writer.cc
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+// 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.
+
+#include "minidump/minidump_string_writer.h"
+
+#include "base/logging.h"
+#include "minidump/minidump_writer_util.h"
+#include "util/numeric/safe_assignment.h"
+
+namespace crashpad {
+namespace internal {
+
+template <typename Traits>
+MinidumpStringWriter<Traits>::MinidumpStringWriter()
+    : MinidumpWritable(), string_base_(), string_() {
+}
+
+template <typename Traits>
+MinidumpStringWriter<Traits>::~MinidumpStringWriter() {
+}
+
+template <typename Traits>
+bool MinidumpStringWriter<Traits>::Freeze() {
+  DCHECK_EQ(state(), kStateMutable);
+
+  if (!MinidumpWritable::Freeze()) {
+    return false;
+  }
+
+  size_t string_bytes = string_.size() * sizeof(string_[0]);
+  if (!AssignIfInRange(&string_base_.Length, string_bytes)) {
+    LOG(ERROR) << "string_bytes " << string_bytes << " out of range";
+    return false;
+  }
+
+  return true;
+}
+
+template <typename Traits>
+size_t MinidumpStringWriter<Traits>::SizeOfObject() {
+  DCHECK_GE(state(), kStateFrozen);
+
+  // Include the NUL terminator.
+  return sizeof(string_base_) + (string_.size() + 1) * sizeof(string_[0]);
+}
+
+template <typename Traits>
+bool MinidumpStringWriter<Traits>::WriteObject(
+    FileWriterInterface* file_writer) {
+  DCHECK_EQ(state(), kStateWritable);
+
+  // The string’s length is stored in string_base_, and its data is stored in
+  // string_. Write them both.
+  WritableIoVec iov;
+  iov.iov_base = &string_base_;
+  iov.iov_len = sizeof(string_base_);
+  std::vector<WritableIoVec> iovecs(1, iov);
+
+  // Include the NUL terminator.
+  iov.iov_base = &string_[0];
+  iov.iov_len = (string_.size() + 1) * sizeof(string_[0]);
+  iovecs.push_back(iov);
+
+  return file_writer->WriteIoVec(&iovecs);
+}
+
+// Explicit template instantiation of the forms of MinidumpStringWriter<> used
+// as base classes.
+template class MinidumpStringWriter<MinidumpStringWriterUTF16Traits>;
+template class MinidumpStringWriter<MinidumpStringWriterUTF8Traits>;
+
+void MinidumpUTF16StringWriter::SetUTF8(const std::string& string_utf8) {
+  DCHECK_EQ(state(), kStateMutable);
+
+  set_string(MinidumpWriterUtil::ConvertUTF8ToUTF16(string_utf8));
+}
+
+}  // namespace internal
+}  // namespace crashpad