blob: c28956b55619e91a8a1fc33a2a378257a1bfff6d [file] [log] [blame]
// 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>
#include "update_engine/graph_types.h"
#include "update_engine/utils.h"
using std::min;
namespace chromeos_update_engine {
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_t bytes_remaining_next_extent =
extents_[next_extent_index_].num_blocks() * block_size_ -
extent_bytes_written_;
CHECK_NE(bytes_remaining_next_extent, static_cast<uint64_t>(0));
size_t bytes_to_write =
static_cast<size_t>(min(static_cast<uint64_t>(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(
utils::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