michael@0: // Copyright (c) 2012 The Chromium Authors. All rights reserved.
michael@0: // Use of this source code is governed by a BSD-style license that can be
michael@0: // found in the LICENSE file.
michael@0: 
michael@0: #ifndef SANDBOX_SRC_WIN2K_THREADPOOL_H_
michael@0: #define SANDBOX_SRC_WIN2K_THREADPOOL_H_
michael@0: 
michael@0: #include <list>
michael@0: #include <algorithm>
michael@0: #include "sandbox/win/src/crosscall_server.h"
michael@0: 
michael@0: namespace sandbox {
michael@0: 
michael@0: // Win2kThreadPool a simple implementation of a thread provider as required
michael@0: // for the sandbox IPC subsystem. See sandbox\crosscall_server.h for the details
michael@0: // and requirements of this interface.
michael@0: //
michael@0: // Implementing the thread provider as a thread pool is desirable in the case
michael@0: // of shared memory IPC because it can generate a large number of waitable
michael@0: // events: as many as channels. A thread pool does not create a thread per
michael@0: // event, instead maintains a few idle threads but can create more if the need
michael@0: // arises.
michael@0: //
michael@0: // This implementation simply thunks to the nice thread pool API of win2k.
michael@0: class Win2kThreadPool : public ThreadProvider {
michael@0:  public:
michael@0:   Win2kThreadPool() {
michael@0:     ::InitializeCriticalSection(&lock_);
michael@0:   }
michael@0:   virtual ~Win2kThreadPool();
michael@0: 
michael@0:   virtual bool RegisterWait(const void* cookie, HANDLE waitable_object,
michael@0:                             CrossCallIPCCallback callback,
michael@0:                             void* context);
michael@0: 
michael@0:   virtual bool UnRegisterWaits(void* cookie);
michael@0: 
michael@0:   // Returns the total number of wait objects associated with
michael@0:   // the thread pool.
michael@0:   size_t OutstandingWaits();
michael@0: 
michael@0:  private:
michael@0:   // record to keep track of a wait and its associated cookie.
michael@0:   struct PoolObject {
michael@0:     const void* cookie;
michael@0:     HANDLE wait;
michael@0:   };
michael@0:   // The list of pool wait objects.
michael@0:   typedef std::list<PoolObject> PoolObjects;
michael@0:   PoolObjects pool_objects_;
michael@0:   // This lock protects the list of pool wait objects.
michael@0:   CRITICAL_SECTION lock_;
michael@0:   DISALLOW_COPY_AND_ASSIGN(Win2kThreadPool);
michael@0: };
michael@0: 
michael@0: }  // namespace sandbox
michael@0: 
michael@0: #endif  // SANDBOX_SRC_WIN2K_THREADPOOL_H_