Add MinidumpFileWriter

minidump/minidump_file_writer.cc

+// 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_file_writer.h"
+
+#include "base/logging.h"
+#include "minidump/minidump_writer_util.h"
+#include "util/numeric/safe_assignment.h"
+
+namespace crashpad {
+
+MinidumpFileWriter::MinidumpFileWriter()
+    : MinidumpWritable(), header_(), streams_(), stream_types_() {
+  // Don’t set the signature field right away. Leave it set to 0, so that a
+  // partially-written minidump file isn’t confused for a complete and valid
+  // one. The header will be rewritten in WriteToFile().
+  header_.Signature = 0;
+
+  header_.Version = MINIDUMP_VERSION;
+  header_.CheckSum = 0;
+  header_.Flags = MiniDumpNormal;
+}
+
+MinidumpFileWriter::~MinidumpFileWriter() {
+}
+
+void MinidumpFileWriter::SetTimestamp(time_t timestamp) {
+  DCHECK_EQ(state(), kStateMutable);
+
+  internal::MinidumpWriterUtil::AssignTimeT(&header_.TimeDateStamp, timestamp);
+}
+
+void MinidumpFileWriter::AddStream(internal::MinidumpStreamWriter* stream) {
+  DCHECK_EQ(state(), kStateMutable);
+
+  MinidumpStreamType stream_type = stream->StreamType();
+
+  auto rv = stream_types_.insert(stream_type);
+  CHECK(rv.second) << "stream_type " << stream_type << " already present";
+
+  streams_.push_back(stream);
+
+  DCHECK_EQ(streams_.size(), stream_types_.size());
+}
+
+bool MinidumpFileWriter::WriteEverything(FileWriterInterface* file_writer) {
+  DCHECK_EQ(state(), kStateMutable);
+
+  off_t start_offset = file_writer->Seek(0, SEEK_CUR);
+  if (start_offset < 0) {
+    return false;
+  }
+
+  if (!MinidumpWritable::WriteEverything(file_writer)) {
+    return false;
+  }
+
+  off_t end_offset = file_writer->Seek(0, SEEK_CUR);
+  if (end_offset < 0) {
+    return false;
+  }
+
+  // Now that the entire minidump file has been completely written, go back to
+  // the beginning and rewrite the header with the correct signature to identify
+  // it as a valid minidump file.
+  header_.Signature = MINIDUMP_SIGNATURE;
+
+  if (file_writer->Seek(start_offset, SEEK_SET) != 0) {
+    return false;
+  }
+
+  if (!file_writer->Write(&header_, sizeof(header_))) {
+    return false;
+  }
+
+  // Seek back to the end of the file, in case some non-minidump content will be
+  // written to the file after the minidump content.
+  return file_writer->Seek(end_offset, SEEK_SET);
+}
+
+bool MinidumpFileWriter::Freeze() {
+  DCHECK_EQ(state(), kStateMutable);
+
+  if (!MinidumpWritable::Freeze()) {
+    return false;
+  }
+
+  size_t stream_count = streams_.size();
+  CHECK_EQ(stream_count, stream_types_.size());
+
+  if (!AssignIfInRange(&header_.NumberOfStreams, stream_count)) {
+    LOG(ERROR) << "stream_count " << stream_count << " out of range";
+    return false;
+  }
+
+  return true;
+}
+
+size_t MinidumpFileWriter::SizeOfObject() {
+  DCHECK_GE(state(), kStateFrozen);
+  DCHECK_EQ(streams_.size(), stream_types_.size());
+
+  return sizeof(header_) + streams_.size() * sizeof(MINIDUMP_DIRECTORY);
+}
+
+std::vector<internal::MinidumpWritable*> MinidumpFileWriter::Children() {
+  DCHECK_GE(state(), kStateFrozen);
+  DCHECK_EQ(streams_.size(), stream_types_.size());
+
+  std::vector<MinidumpWritable*> children;

[Robert Sesek, 2014/08/03 15:19:59]

You're building a vector<MinidumpWritable*> yet the return type is of
vector<internal::MinidumpWitable*>. Any reason to not just use
std::vector<T>::vector(const std::vector<T>&) copy constructor?

[Mark Mentovai, 2014/08/03 20:14:10]

rsesek wrote:
streams_ is std::vector<MinidumpStream*> and the return type is
std::vector<MinidumpWritable*>. MinidumpStream inherits from MinidumpWritable,
so a MinidumpStream* is also a MinidumpWritable*, but a vector of
MinidumpStream* isn’t compatible with a vector of MinidumpWritable*.

This is just the way the language works. It’s a limitation of std::vector, I
don’t think it’s worth a comment.

[Robert Sesek, 2014/08/03 21:20:55]

Ack. I misread streams_ as MinidumpWritable* instead of MinidumpStreamWriter.

+  for (internal::MinidumpStreamWriter* stream : streams_) {
+    children.push_back(stream);
+  }
+
+  return children;
+}
+
+bool MinidumpFileWriter::WillWriteAtOffsetImpl(off_t offset) {
+  DCHECK_EQ(state(), kStateFrozen);
+  DCHECK_EQ(offset, 0);
+  DCHECK_EQ(streams_.size(), stream_types_.size());
+
+  auto directory_offset = streams_.empty() ? 0 : offset + sizeof(header_);
+  if (!AssignIfInRange(&header_.StreamDirectoryRva, directory_offset)) {
+    LOG(ERROR) << "offset " << directory_offset << " out of range";
+    return false;
+  }
+
+  return MinidumpWritable::WillWriteAtOffsetImpl(offset);
+}
+
+bool MinidumpFileWriter::WriteObject(FileWriterInterface* file_writer) {
+  DCHECK_EQ(state(), kStateWritable);
+  DCHECK_EQ(streams_.size(), stream_types_.size());
+
+  WritableIoVec iov;
+  iov.iov_base = &header_;
+  iov.iov_len = sizeof(header_);
+  std::vector<WritableIoVec> iovecs(1, iov);
+
+  if (!streams_.empty()) {
+    iov.iov_len = sizeof(MINIDUMP_DIRECTORY);

[Robert Sesek, 2014/08/03 15:19:59]

If you moved this into the loop body, you could remove the empty check and do
the for loop unconditionally.

+    for (internal::MinidumpStreamWriter* stream : streams_) {
+      iov.iov_base = stream->DirectoryListEntry();
+      iovecs.push_back(iov);
+    }
+  }
+
+  return file_writer->WriteIoVec(&iovecs);
+}
+
+}  // namespace crashpad