Move mojo edk into mojo/edk

mojo/embedder/platform_shared_buffer.h

-// Copyright 2014 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.
-
-#ifndef MOJO_EMBEDDER_PLATFORM_SHARED_BUFFER_H_
-#define MOJO_EMBEDDER_PLATFORM_SHARED_BUFFER_H_
-
-#include <stddef.h>
-
-#include "base/macros.h"
-#include "base/memory/ref_counted.h"
-#include "base/memory/scoped_ptr.h"
-#include "mojo/embedder/scoped_platform_handle.h"
-#include "mojo/system/system_impl_export.h"
-
-namespace mojo {
-namespace embedder {
-
-class PlatformSharedBufferMapping;
-
-// |PlatformSharedBuffer| is an interface for a thread-safe, ref-counted wrapper
-// around OS-specific shared memory. It has the following features:
-//   - A |PlatformSharedBuffer| simply represents a piece of shared memory that
-//     *may* be mapped and *may* be shared to another process.
-//   - A single |PlatformSharedBuffer| may be mapped multiple times. The
-//     lifetime of the mapping (owned by |PlatformSharedBufferMapping|) is
-//     separate from the lifetime of the |PlatformSharedBuffer|.
-//   - Sizes/offsets (of the shared memory and mappings) are arbitrary, and not
-//     restricted by page size. However, more memory may actually be mapped than
-//     requested.
-//
-// It currently does NOT support the following:
-//   - Sharing read-only. (This will probably eventually be supported.)
-//
-// TODO(vtl): Rectify this with |base::SharedMemory|.
-class MOJO_SYSTEM_IMPL_EXPORT PlatformSharedBuffer
-    : public base::RefCountedThreadSafe<PlatformSharedBuffer> {
- public:
-  // Gets the size of shared buffer (in number of bytes).
-  virtual size_t GetNumBytes() const = 0;
-
-  // Maps (some) of the shared buffer into memory; [|offset|, |offset + length|]
-  // must be contained in [0, |num_bytes|], and |length| must be at least 1.
-  // Returns null on failure.
-  virtual scoped_ptr<PlatformSharedBufferMapping> Map(size_t offset,
-                                                      size_t length) = 0;
-
-  // Checks if |offset| and |length| are valid arguments.
-  virtual bool IsValidMap(size_t offset, size_t length) = 0;
-
-  // Like |Map()|, but doesn't check its arguments (which should have been
-  // preflighted using |IsValidMap()|).
-  virtual scoped_ptr<PlatformSharedBufferMapping> MapNoCheck(size_t offset,
-                                                             size_t length) = 0;
-
-  // Duplicates the underlying platform handle and passes it to the caller.
-  // TODO(vtl): On POSIX, we'll need two FDs to support sharing read-only.
-  virtual ScopedPlatformHandle DuplicatePlatformHandle() = 0;
-
-  // Passes the underlying platform handle to the caller. This should only be
-  // called if there's a unique reference to this object (owned by the caller).
-  // After calling this, this object should no longer be used, but should only
-  // be disposed of.
-  virtual ScopedPlatformHandle PassPlatformHandle() = 0;
-
- protected:
-  friend class base::RefCountedThreadSafe<PlatformSharedBuffer>;
-
-  PlatformSharedBuffer() {}
-  virtual ~PlatformSharedBuffer() {}
-
- private:
-  DISALLOW_COPY_AND_ASSIGN(PlatformSharedBuffer);
-};
-
-// An interface for a mapping of a |PlatformSharedBuffer| (compararable to a
-// "file view" in Windows); see above. Created by (implementations of)
-// |PlatformSharedBuffer::Map()|. Automatically unmaps memory on destruction.
-//
-// Mappings are NOT thread-safe.
-//
-// Note: This is an entirely separate class (instead of
-// |PlatformSharedBuffer::Mapping|) so that it can be forward-declared.
-class MOJO_SYSTEM_IMPL_EXPORT PlatformSharedBufferMapping {
- public:
-  // IMPORTANT: Implementations must implement a destructor that unmaps memory.
-  virtual ~PlatformSharedBufferMapping() {}
-
-  virtual void* GetBase() const = 0;
-  virtual size_t GetLength() const = 0;
-
- protected:
-  PlatformSharedBufferMapping() {}
-
- private:
-  DISALLOW_COPY_AND_ASSIGN(PlatformSharedBufferMapping);
-};
-
-}  // namespace embedder
-}  // namespace mojo
-
-#endif  // MOJO_EMBEDDER_PLATFORM_SHARED_BUFFER_H_