base/files/memory_mapped_file_win.cc

   1 // Copyright 2013 The Chromium Authors. All rights reserved.
   2 // Use of this source code is governed by a BSD-style license that can be
   3 // found in the LICENSE file.
   4
   5 #include "base/files/memory_mapped_file.h"
   6
   7 #include "base/files/file_path.h"
   8 #include "base/logging.h"
   9 #include "base/metrics/histogram.h"
  10 #include "base/string16.h"
  11 #include "base/threading/thread_restrictions.h"
  12
  13 namespace base {
  14
  15 MemoryMappedFile::MemoryMappedFile()
  16     : file_(INVALID_HANDLE_VALUE),
  17       file_mapping_(INVALID_HANDLE_VALUE),
  18       data_(NULL),
  19       length_(INVALID_FILE_SIZE) {
  20 }
  21
  22 bool MemoryMappedFile::InitializeAsImageSection(const FilePath& file_name) {
  23   if (IsValid())
  24     return false;
  25   file_ = CreatePlatformFile(file_name, PLATFORM_FILE_OPEN | PLATFORM_FILE_READ,
  26                              NULL, NULL);
  27
  28   if (file_ == kInvalidPlatformFileValue) {
  29     DLOG(ERROR) << "Couldn't open " << file_name.AsUTF8Unsafe();
  30     return false;
  31   }
  32
  33   if (!MapFileToMemoryInternalEx(SEC_IMAGE)) {
  34     CloseHandles();
  35     return false;
  36   }
  37
  38   return true;
  39 }
  40
  41 bool MemoryMappedFile::MapFileToMemoryInternal() {
  42   return MapFileToMemoryInternalEx(0);
  43 }
  44
  45 bool MemoryMappedFile::MapFileToMemoryInternalEx(int flags) {
  46   ThreadRestrictions::AssertIOAllowed();
  47
  48   if (file_ == INVALID_HANDLE_VALUE)
  49     return false;
  50
  51   length_ = ::GetFileSize(file_, NULL);
  52   if (length_ == INVALID_FILE_SIZE)
  53     return false;
  54
  55   file_mapping_ = ::CreateFileMapping(file_, NULL, PAGE_READONLY | flags,
  56                                       0, 0, NULL);
  57   if (!file_mapping_) {
  58     // According to msdn, system error codes are only reserved up to 15999.
  59     // http://msdn.microsoft.com/en-us/library/ms681381(v=VS.85).aspx.
  60     UMA_HISTOGRAM_ENUMERATION("MemoryMappedFile.CreateFileMapping",
  61                               logging::GetLastSystemErrorCode(), 16000);
  62     return false;
  63   }
  64
  65   data_ = static_cast<uint8*>(
  66       ::MapViewOfFile(file_mapping_, FILE_MAP_READ, 0, 0, 0));
  67   if (!data_) {
  68     UMA_HISTOGRAM_ENUMERATION("MemoryMappedFile.MapViewOfFile",
  69                               logging::GetLastSystemErrorCode(), 16000);
  70   }
  71   return data_ != NULL;
  72 }
  73
  74 void MemoryMappedFile::CloseHandles() {
  75   if (data_)
  76     ::UnmapViewOfFile(data_);
  77   if (file_mapping_ != INVALID_HANDLE_VALUE)
  78     ::CloseHandle(file_mapping_);
  79   if (file_ != INVALID_HANDLE_VALUE)
  80     ::CloseHandle(file_);
  81
  82   data_ = NULL;
  83   file_mapping_ = file_ = INVALID_HANDLE_VALUE;
  84   length_ = INVALID_FILE_SIZE;
  85 }
  86
  87 }  // namespace base