Index: buffered_file_writer.cc |
diff --git a/buffered_file_writer.cc b/buffered_file_writer.cc |
new file mode 100644 |
index 0000000000000000000000000000000000000000..03b8c77bc9616298d4a64e80752fa9d0c1f4265a |
--- /dev/null |
+++ b/buffered_file_writer.cc |
@@ -0,0 +1,60 @@ |
+// Copyright (c) 2010 The Chromium OS Authors. All rights reserved. |
+// Use of this source code is governed by a BSD-style license that can be |
+// found in the LICENSE file. |
+ |
+#include "update_engine/buffered_file_writer.h" |
+ |
+namespace chromeos_update_engine { |
+ |
+BufferedFileWriter::BufferedFileWriter(FileWriter* next, size_t buffer_size) |
+ : next_(next), |
+ buffer_(new char[buffer_size]), |
+ buffer_size_(buffer_size), |
+ buffered_bytes_(0) {} |
+ |
+BufferedFileWriter::~BufferedFileWriter() {} |
+ |
+int BufferedFileWriter::Open(const char* path, int flags, mode_t mode) { |
+ return next_->Open(path, flags, mode); |
+} |
+ |
+ssize_t BufferedFileWriter::Write(const void* bytes, size_t count) { |
+ size_t copied_bytes = 0; |
+ while (copied_bytes < count) { |
+ // Buffers as many bytes as possible. |
+ size_t remaining_free = buffer_size_ - buffered_bytes_; |
+ size_t copy_bytes = count - copied_bytes; |
+ if (copy_bytes > remaining_free) { |
+ copy_bytes = remaining_free; |
+ } |
+ const char* char_bytes = reinterpret_cast<const char*>(bytes); |
+ memcpy(&buffer_[buffered_bytes_], char_bytes + copied_bytes, copy_bytes); |
+ buffered_bytes_ += copy_bytes; |
+ copied_bytes += copy_bytes; |
+ |
+ // If full, sends the buffer to the next FileWriter. |
+ if (buffered_bytes_ == buffer_size_) { |
+ ssize_t rc = WriteBuffer(); |
+ if (rc < 0) |
+ return rc; |
+ } |
+ } |
+ return count; |
+} |
+ |
+int BufferedFileWriter::Close() { |
+ // Flushes the buffer first, then closes the next FileWriter. |
+ ssize_t rc_write = WriteBuffer(); |
+ int rc_close = next_->Close(); |
+ return (rc_write < 0) ? rc_write : rc_close; |
+} |
+ |
+ssize_t BufferedFileWriter::WriteBuffer() { |
+ if (buffered_bytes_ == 0) |
+ return 0; |
+ ssize_t rc = next_->Write(&buffer_[0], buffered_bytes_); |
+ buffered_bytes_ = 0; |
+ return rc; |
+} |
+ |
+} // namespace chromeos_update_engine |