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 // 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.

 #ifndef BASE_WIN_SCOPED_PROCESS_INFORMATION_H_

 #define BASE_WIN_SCOPED_PROCESS_INFORMATION_H_

 #include <windows.h>

 #include "base/basictypes.h"

 #include "base/base_export.h"

 #include "base/win/scoped_handle.h"

 namespace base {

 namespace win {

 // Manages the closing of process and thread handles from PROCESS_INFORMATION

 // structures. Allows clients to take ownership of either handle independently.

 class BASE_EXPORT ScopedProcessInformation {

  public:

   // Helper object to contain the effect of Receive() to the funtion that needs

   // a pointer.

   class Receiver {

    public:

     explicit Receiver(ScopedProcessInformation* owner)

         : info_(),

           owner_(owner) {}

     ~Receiver() { owner_->Set(info_); }

     operator PROCESS_INFORMATION*() { return &info_; }

    private:

     PROCESS_INFORMATION info_;

     ScopedProcessInformation* owner_;

   };

   ScopedProcessInformation();

   ~ScopedProcessInformation();

   // Returns an object that may be passed to API calls such as CreateProcess.

   // DCHECKs that the object is not currently holding any handles.

   // HANDLEs stored in the returned PROCESS_INFORMATION will be owned by this

   // instance.

   // The intended use case is something like this:

   //   if (::CreateProcess(..., startup_info, scoped_proces_info.Receive()))

   Receiver Receive();

   // Returns true iff this instance is holding a thread and/or process handle.

   bool IsValid() const;

   // Closes the held thread and process handles, if any.

   void Close();

   // Populates this instance with the provided |process_info|.

   void Set(const PROCESS_INFORMATION& process_info);

   // Populates this instance with duplicate handles and the thread/process IDs

   // from |other|. Returns false in case of failure, in which case this instance

   // will be completely unpopulated.

   bool DuplicateFrom(const ScopedProcessInformation& other);

   // Transfers ownership of the held PROCESS_INFORMATION, if any, away from this

   // instance.

   PROCESS_INFORMATION Take();

   // Transfers ownership of the held process handle, if any, away from this

   // instance. Note that the related process_id will also be cleared.

   HANDLE TakeProcessHandle();

   // Transfers ownership of the held thread handle, if any, away from this

   // instance. Note that the related thread_id will also be cleared.

   HANDLE TakeThreadHandle();

   // Returns the held process handle, if any, while retaining ownership.

   HANDLE process_handle() const {

     return process_handle_.Get();

   }

   // Returns the held thread handle, if any, while retaining ownership.

   HANDLE thread_handle() const {

     return thread_handle_.Get();

   }

   // Returns the held process id, if any.

   DWORD process_id() const {

     return process_id_;

   }

   // Returns the held thread id, if any.

   DWORD thread_id() const {

     return thread_id_;

   }

  private:

   ScopedHandle process_handle_;

   ScopedHandle thread_handle_;

   DWORD process_id_;

   DWORD thread_id_;

   DISALLOW_COPY_AND_ASSIGN(ScopedProcessInformation);

 };

 }  // namespace win

 }  // namespace base

 #endif  // BASE_WIN_SCOPED_PROCESS_INFORMATION_H_