Move Windows Sandbox, trybots version (don't commit me!)

sandbox/src/shared_handles.h

-// Copyright (c) 2010 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 SANDBOX_SRC_SHARED_HANDLES_H__
-#define SANDBOX_SRC_SHARED_HANDLES_H__
-
-#include "base/basictypes.h"
-
-#ifndef HANDLE
-// We can provide our own windows compatilble handle definition, but
-// in general we want to rely on the client of this api to include
-// the proper windows headers. Note that we don't want to bring the
-// whole <windows.h> into scope if we don't have to.
-typedef void* HANDLE;
-#endif
-
-namespace sandbox {
-
-// SharedHandles is a simple class to stash and find windows object handles
-// given a raw block of memory which is shared between two processes.
-// It addresses the need to communicate a handle value between two windows
-// processes given that they are already sharing some memory.
-//
-// This class is not exposed directly to users of the sanbox API, instead
-// we expose the wrapper methods TargetProcess::TransferHandle( ) and
-// TargetServices::GetTransferHandle()
-//
-// Use it for a small number of items, since internaly uses linear seach
-//
-// The use is very simple. Given a shared memory between proces A and B:
-// process A:
-//  HANDLE handle = SomeFunction(..);
-//  SharedHandles shared_handes;
-//  shared_handles.Init(memory)
-//  shared_handles.SetHandle(3, handle);
-//
-// process B:
-//  SharedHandles shared_handes;
-//  shared_handles.Init(memory)
-//  HANDLE handle = shared_handles.GetHandle(3);
-//
-// Note that '3' in this example is a unique id, that must be agreed before
-// transfer
-//
-// Note2: While this class can be used in a single process, there are
-// better alternatives such as STL
-//
-// Note3: Under windows a kernel object handle in one process does not
-// make sense for another process unless there is a DuplicateHandle( )
-// call involved which this class DOES NOT do that for you.
-//
-// Note4: Under windows, shared memory when created is initialized to
-// zeros always. If you are not using shared memory it is your responsability
-// to zero it for the setter process and to copy it to the getter process.
-class SharedHandles {
- public:
-  SharedHandles();
-
-  // Initializes the shared memory for use.
-  // Pass the shared memory base and size. It will internally compute
-  // how many handles can it store. If initialization fails the return value
-  // is false.
-  bool Init(void* raw_mem, size_t size_bytes);
-
-  // Sets a handle in the shared memory for transfer.
-  // Parameters:
-  // tag : an integer, different from zero that uniquely identfies the
-  // handle to transfer.
-  // handle: the handle value associated with 'tag' to tranfer
-  // Returns false if there is not enough space in the shared memory for
-  // this handle.
-  bool SetHandle(uint32 tag, HANDLE handle);
-
-  // Gets a handle previously stored by SetHandle.
-  // Parameters:
-  // tag: an integer different from zero that uniquely identfies the handle
-  // to retrieve.
-  // *handle: output handle value if the call was succesful.
-  // If a handle with the provided tag is not found the return value is false.
-  // If the tag is found the return value is true.
-  bool GetHandle(uint32 tag, HANDLE* handle);
-
- private:
-  // A single item is the tuple handle/tag
-  struct SharedItem {
-    uint32 tag;
-    void* item;
-  };
-
-  // SharedMem is used to layout the memory as an array of SharedItems
-  struct SharedMem {
-    size_t max_items;
-    SharedItem* items;
-  };
-
-  // Finds an Item tuple provided the handle tag.
-  // Uses linear search because we expect the number of handles to be
-  // small (say less than ~100).
-  SharedItem* FindByTag(uint32 tag);
-
-  SharedMem shared_;
-  DISALLOW_COPY_AND_ASSIGN(SharedHandles);
-};
-
-}  // namespace sandbox
-
-#endif  // SANDBOX_SRC_SHARED_HANDLES_H__