Add FileReaderInterface. Move StringFileWriter to StringFile and

util/file/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 "util/file/file_writer.h"
 
 #include <algorithm>
 
 #include <limits.h>
 
 #include "base/logging.h"
+#include "base/numerics/safe_conversions.h"
+#include "build/build_config.h"
 
 #if defined(OS_POSIX)
 #include <sys/uio.h>
 #include <unistd.h>
 #include "base/posix/eintr_wrapper.h"
 #endif  // OS_POSIX
 
 namespace crashpad {
 
 #if defined(OS_POSIX)
 // Ensure type compatibility between WritableIoVec and iovec.
 static_assert(sizeof(WritableIoVec) == sizeof(iovec), "WritableIoVec size");
 static_assert(offsetof(WritableIoVec, iov_base) == offsetof(iovec, iov_base),
               "WritableIoVec base offset");
 static_assert(offsetof(WritableIoVec, iov_len) == offsetof(iovec, iov_len),
               "WritableIoVec len offset");
 #endif  // OS_POSIX
 
 WeakFileHandleFileWriter::WeakFileHandleFileWriter(FileHandle file_handle)
     : file_handle_(file_handle) {
 }
 
 WeakFileHandleFileWriter::~WeakFileHandleFileWriter() {
 }
 
 bool WeakFileHandleFileWriter::Write(const void* data, size_t size) {
   DCHECK_NE(file_handle_, kInvalidFileHandle);
-
-  // TODO(mark): Write no more than SSIZE_MAX bytes in a single call.
-  ssize_t written = WriteFile(file_handle_, data, size);
-  if (written < 0) {
-    PLOG(ERROR) << "write";
-    return false;
-  } else if (written == 0) {
-    LOG(ERROR) << "write: returned 0";
-    return false;
-  }
-
-  return true;
+  return LoggingWriteFile(file_handle_, data, size);
 }
 
 bool WeakFileHandleFileWriter::WriteIoVec(std::vector<WritableIoVec>* iovecs) {
   DCHECK_NE(file_handle_, kInvalidFileHandle);
 
 #if defined(OS_POSIX)
 
   ssize_t size = 0;
   for (const WritableIoVec& iov : *iovecs) {
     // TODO(mark): Check to avoid overflow of ssize_t, and fail with EINVAL.
@@ skipping 107 matching lines @@
   DCHECK(file_.is_valid());
   return weak_file_handle_file_writer_.WriteIoVec(iovecs);
 }
 
 FileOffset FileWriter::Seek(FileOffset offset, int whence) {
   DCHECK(file_.is_valid());
   return weak_file_handle_file_writer_.Seek(offset, whence);
 }
 
 }  // namespace crashpad