Index: src/platform/update_engine/extent_writer.cc |
diff --git a/src/platform/update_engine/extent_writer.cc b/src/platform/update_engine/extent_writer.cc |
new file mode 100644 |
index 0000000000000000000000000000000000000000..1ae565b03776549be8c1820663f16fb9bab7e399 |
--- /dev/null |
+++ b/src/platform/update_engine/extent_writer.cc |
@@ -0,0 +1,67 @@ |
+// Copyright (c) 2009 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/extent_writer.h" |
+#include <errno.h> |
+#include <unistd.h> |
+#include <algorithm> |
+ |
+using std::min; |
+ |
+namespace chromeos_update_engine { |
+ |
+namespace { |
+// Returns true on success. |
+bool WriteAll(int fd, const void *buf, size_t count) { |
+ const char* c_buf = reinterpret_cast<const char*>(buf); |
+ ssize_t bytes_written = 0; |
+ while (bytes_written < static_cast<ssize_t>(count)) { |
+ ssize_t rc = write(fd, c_buf + bytes_written, count - bytes_written); |
+ TEST_AND_RETURN_FALSE_ERRNO(rc >= 0); |
+ bytes_written += rc; |
+ } |
+ return true; |
+} |
+} |
+ |
+bool DirectExtentWriter::Write(const void* bytes, size_t count) { |
+ if (count == 0) |
+ return true; |
+ const char* c_bytes = reinterpret_cast<const char*>(bytes); |
+ size_t bytes_written = 0; |
+ while (count - bytes_written > 0) { |
+ TEST_AND_RETURN_FALSE(next_extent_index_ < extents_.size()); |
+ uint64 bytes_remaining_next_extent = |
+ extents_[next_extent_index_].num_blocks() * block_size_ - |
+ extent_bytes_written_; |
+ CHECK_NE(bytes_remaining_next_extent, 0); |
+ size_t bytes_to_write = |
+ static_cast<size_t>(min(static_cast<uint64>(count - bytes_written), |
+ bytes_remaining_next_extent)); |
+ TEST_AND_RETURN_FALSE(bytes_to_write > 0); |
+ |
+ if (extents_[next_extent_index_].start_block() != kSparseHole) { |
+ const off64_t offset = |
+ extents_[next_extent_index_].start_block() * block_size_ + |
+ extent_bytes_written_; |
+ TEST_AND_RETURN_FALSE_ERRNO(lseek64(fd_, offset, SEEK_SET) != |
+ static_cast<off64_t>(-1)); |
+ TEST_AND_RETURN_FALSE( |
+ WriteAll(fd_, c_bytes + bytes_written, bytes_to_write)); |
+ } |
+ bytes_written += bytes_to_write; |
+ extent_bytes_written_ += bytes_to_write; |
+ if (bytes_remaining_next_extent == bytes_to_write) { |
+ // We filled this extent |
+ CHECK_EQ(extent_bytes_written_, |
+ extents_[next_extent_index_].num_blocks() * block_size_); |
+ // move to next extent |
+ extent_bytes_written_ = 0; |
+ next_extent_index_++; |
+ } |
+ } |
+ return true; |
+} |
+ |
+} // namespace chromeos_update_engine |