base: Move MemoryMappedFile out of file_util.h and into its own header file.

base/files/memory_mapped_file_win.cc

+// Copyright 2013 The Chromium 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 "base/files/memory_mapped_file.h"
+
+#include "base/file_path.h"
+#include "base/logging.h"
+#include "base/metrics/histogram.h"
+#include "base/string16.h"
+#include "base/threading/thread_restrictions.h"
+
+namespace base {
+
+MemoryMappedFile::MemoryMappedFile()
+    : file_(INVALID_HANDLE_VALUE),
+      file_mapping_(INVALID_HANDLE_VALUE),
+      data_(NULL),
+      length_(INVALID_FILE_SIZE) {
+}
+
+bool MemoryMappedFile::InitializeAsImageSection(const FilePath& file_name) {
+  if (IsValid())
+    return false;
+  file_ = CreatePlatformFile(file_name, PLATFORM_FILE_OPEN | PLATFORM_FILE_READ,
+                             NULL, NULL);
+
+  if (file_ == kInvalidPlatformFileValue) {
+    DLOG(ERROR) << "Couldn't open " << file_name.AsUTF8Unsafe();
+    return false;
+  }
+
+  if (!MapFileToMemoryInternalEx(SEC_IMAGE)) {
+    CloseHandles();
+    return false;
+  }
+
+  return true;
+}
+
+bool MemoryMappedFile::MapFileToMemoryInternal() {
+  return MapFileToMemoryInternalEx(0);
+}
+
+bool MemoryMappedFile::MapFileToMemoryInternalEx(int flags) {
+  ThreadRestrictions::AssertIOAllowed();
+
+  if (file_ == INVALID_HANDLE_VALUE)
+    return false;
+
+  length_ = ::GetFileSize(file_, NULL);
+  if (length_ == INVALID_FILE_SIZE)
+    return false;
+
+  file_mapping_ = ::CreateFileMapping(file_, NULL, PAGE_READONLY | flags,
+                                      0, 0, NULL);
+  if (!file_mapping_) {
+    // According to msdn, system error codes are only reserved up to 15999.
+    // http://msdn.microsoft.com/en-us/library/ms681381(v=VS.85).aspx.
+    UMA_HISTOGRAM_ENUMERATION("MemoryMappedFile.CreateFileMapping",
+                              logging::GetLastSystemErrorCode(), 16000);
+    return false;
+  }
+
+  data_ = static_cast<uint8*>(
+      ::MapViewOfFile(file_mapping_, FILE_MAP_READ, 0, 0, 0));
+  if (!data_) {
+    UMA_HISTOGRAM_ENUMERATION("MemoryMappedFile.MapViewOfFile",
+                              logging::GetLastSystemErrorCode(), 16000);
+  }
+  return data_ != NULL;
+}
+
+void MemoryMappedFile::CloseHandles() {
+  if (data_)
+    ::UnmapViewOfFile(data_);
+  if (file_mapping_ != INVALID_HANDLE_VALUE)
+    ::CloseHandle(file_mapping_);
+  if (file_ != INVALID_HANDLE_VALUE)
+    ::CloseHandle(file_);
+
+  data_ = NULL;
+  file_mapping_ = file_ = INVALID_HANDLE_VALUE;
+  length_ = INVALID_FILE_SIZE;
+}
+
+}  // namespace base