1//===- FileOutputBuffer.cpp -----------------------------------------------===//
2//
3//                     The MCLinker Project
4//
5// This file is distributed under the University of Illinois Open Source
6// License. See LICENSE.TXT for details.
7//
8//===----------------------------------------------------------------------===//
9#include "mcld/Support/FileOutputBuffer.h"
10#include "mcld/Support/FileHandle.h"
11#include "mcld/Support/Path.h"
12
13namespace mcld {
14
15FileOutputBuffer::FileOutputBuffer(llvm::sys::fs::mapped_file_region* pRegion,
16                                   FileHandle& pFileHandle)
17    : m_pRegion(pRegion), m_FileHandle(pFileHandle) {
18}
19
20FileOutputBuffer::~FileOutputBuffer() {
21  // Unmap buffer, letting OS flush dirty pages to file on disk.
22  m_pRegion.reset();
23}
24
25std::error_code
26FileOutputBuffer::create(FileHandle& pFileHandle,
27                         size_t pSize,
28                         std::unique_ptr<FileOutputBuffer>& pResult) {
29  std::error_code ec;
30
31  // Resize the file before mapping the file region.
32  ec = llvm::sys::fs::resize_file(pFileHandle.handler(), pSize);
33  if (ec)
34    return ec;
35
36  std::unique_ptr<llvm::sys::fs::mapped_file_region> mapped_file(
37      new llvm::sys::fs::mapped_file_region(pFileHandle.handler(),
38          llvm::sys::fs::mapped_file_region::readwrite, pSize, 0, ec));
39  if (ec)
40    return ec;
41
42  pResult.reset(new FileOutputBuffer(mapped_file.get(), pFileHandle));
43  if (pResult)
44    mapped_file.release();
45
46  return std::error_code();
47}
48
49MemoryRegion FileOutputBuffer::request(size_t pOffset, size_t pLength) {
50  if (pOffset > getBufferSize() || (pOffset + pLength) > getBufferSize())
51    return MemoryRegion();
52  return MemoryRegion(getBufferStart() + pOffset, pLength);
53}
54
55llvm::StringRef FileOutputBuffer::getPath() const {
56  return m_FileHandle.path().native();
57}
58
59}  // namespace mcld
60