Implement the memory mapped file class for posix.

base/file_util.cc

 // Copyright (c) 2006-2008 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/file_util.h"
 
 #include <stdio.h>
 
 #include <fstream>
 
@@ skipping 257 matching lines @@
   *file_size = info.size;
   return true;
 }
 
 bool CloseFile(FILE* file) {
   if (file == NULL)
     return true;
   return fclose(file) == 0;
 }
 
+///////////////////////////////////////////////
+// MemoryMappedFile
+
+MemoryMappedFile::~MemoryMappedFile() {
+  CloseHandles();
+}
+
+bool MemoryMappedFile::Initialize(const FilePath& file_name) {
+  if (IsValid())
+    return false;
+
+  if (!MapFileToMemory(file_name)) {
+    CloseHandles();
+    return false;
+  }
+
+  return true;
+}
+
+bool MemoryMappedFile::IsValid() {
+  return data_ != NULL;
+}
+
 // Deprecated functions ----------------------------------------------------
 
 bool AbsolutePath(std::wstring* path_str) {
   FilePath path(FilePath::FromWStringHack(*path_str));
   if (!AbsolutePath(&path))
     return false;
   *path_str = path.ToWStringHack();
   return true;
 }
 void AppendToPath(std::wstring* path, const std::wstring& new_ending) {
@@ skipping 102 matching lines @@
   FilePath directory = path.DirName();
   // If there is no separator, we will get back kCurrentDirectory.
   // In this case, clear dir.
   if (directory == path || directory.value() == FilePath::kCurrentDirectory)
     dir->clear();
   else
     *dir = directory.ToWStringHack();
 }
 }  // namespace