1 files changed, 73 insertions, 0 deletions
diff --git a/chromium/net/disk_cache/mapped_file.h b/chromium/net/disk_cache/mapped_file.h
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index 00000000000..4649b90d1c9
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+++ b/chromium/net/disk_cache/mapped_file.h
@@ -0,0 +1,73 @@
+// Copyright (c) 2012 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.
+
+// See net/disk_cache/disk_cache.h for the public interface of the cache.
+
+#ifndef NET_DISK_CACHE_MAPPED_FILE_H_
+#define NET_DISK_CACHE_MAPPED_FILE_H_
+
+#include "net/base/net_export.h"
+#include "net/disk_cache/file.h"
+#include "net/disk_cache/file_block.h"
+
+namespace base {
+class FilePath;
+}
+
+namespace disk_cache {
+
+// This class implements a memory mapped file used to access block-files. The
+// idea is that the header and bitmap will be memory mapped all the time, and
+// the actual data for the blocks will be access asynchronously (most of the
+// time).
+class NET_EXPORT_PRIVATE MappedFile : public File {
+ public:
+  MappedFile() : File(true), init_(false) {}
+
+  // Performs object initialization. name is the file to use, and size is the
+  // amount of data to memory map from the file. If size is 0, the whole file
+  // will be mapped in memory.
+  void* Init(const base::FilePath& name, size_t size);
+
+  void* buffer() const {
+    return buffer_;
+  }
+
+  // Loads or stores a given block from the backing file (synchronously).
+  bool Load(const FileBlock* block);
+  bool Store(const FileBlock* block);
+
+  // Flush the memory-mapped section to disk (synchronously).
+  void Flush();
+
+ private:
+  virtual ~MappedFile();
+
+  bool init_;
+#if defined(OS_WIN)
+  HANDLE section_;
+#endif
+  void* buffer_;  // Address of the memory mapped buffer.
+  size_t view_size_;  // Size of the memory pointed by buffer_.
+#if defined(POSIX_AVOID_MMAP)
+  void* snapshot_;  // Copy of the buffer taken when it was last flushed.
+#endif
+
+  DISALLOW_COPY_AND_ASSIGN(MappedFile);
+};
+
+// Helper class for calling Flush() on exit from the current scope.
+class ScopedFlush {
+ public:
+  explicit ScopedFlush(MappedFile* file) : file_(file) {}
+  ~ScopedFlush() {
+    file_->Flush();
+  }
+ private:
+  MappedFile* file_;
+};
+
+}  // namespace disk_cache
+
+#endif  // NET_DISK_CACHE_MAPPED_FILE_H_