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      1 // Copyright (c) 2011 The Chromium Authors. All rights reserved.
      2 // Use of this source code is governed by a BSD-style license that can be
      3 // found in the LICENSE file.
      4 
      5 #ifndef IPC_IPC_PLATFORM_FILE_H_
      6 #define IPC_IPC_PLATFORM_FILE_H_
      7 
      8 #include "base/files/file.h"
      9 #include "base/process/process.h"
     10 #include "build/build_config.h"
     11 #include "ipc/ipc_message_support_export.h"
     12 
     13 #if defined(OS_POSIX) || defined(OS_FUCHSIA)
     14 #include "base/file_descriptor_posix.h"
     15 #endif
     16 
     17 namespace IPC {
     18 
     19 #if defined(OS_WIN)
     20 class IPC_MESSAGE_SUPPORT_EXPORT PlatformFileForTransit {
     21  public:
     22   // Creates an invalid platform file.
     23   PlatformFileForTransit();
     24 
     25   // Creates a platform file that takes unofficial ownership of |handle|. Note
     26   // that ownership is not handled by a Scoped* class due to usage patterns of
     27   // this class and its POSIX counterpart [base::FileDescriptor]. When this
     28   // class is used as an input to an IPC message, the IPC subsystem will close
     29   // |handle|. When this class is used as the output from an IPC message, the
     30   // receiver is expected to take ownership of |handle|.
     31   explicit PlatformFileForTransit(HANDLE handle);
     32 
     33   // Comparison operators.
     34   bool operator==(const PlatformFileForTransit& platform_file) const;
     35   bool operator!=(const PlatformFileForTransit& platform_file) const;
     36 
     37   HANDLE GetHandle() const;
     38   bool IsValid() const;
     39 
     40  private:
     41   HANDLE handle_;
     42 };
     43 #elif defined(OS_POSIX) || defined(OS_FUCHSIA)
     44 typedef base::FileDescriptor PlatformFileForTransit;
     45 #endif
     46 
     47 inline PlatformFileForTransit InvalidPlatformFileForTransit() {
     48 #if defined(OS_WIN)
     49   return PlatformFileForTransit();
     50 #elif defined(OS_POSIX) || defined(OS_FUCHSIA)
     51   return base::FileDescriptor();
     52 #endif
     53 }
     54 
     55 inline base::PlatformFile PlatformFileForTransitToPlatformFile(
     56     const PlatformFileForTransit& transit) {
     57 #if defined(OS_WIN)
     58   return transit.GetHandle();
     59 #elif defined(OS_POSIX) || defined(OS_FUCHSIA)
     60   return transit.fd;
     61 #endif
     62 }
     63 
     64 inline base::File PlatformFileForTransitToFile(
     65     const PlatformFileForTransit& transit) {
     66 #if defined(OS_WIN)
     67   return base::File(transit.GetHandle());
     68 #elif defined(OS_POSIX) || defined(OS_FUCHSIA)
     69   return base::File(transit.fd);
     70 #endif
     71 }
     72 
     73 // Creates a new handle that can be passed through IPC. The result must be
     74 // passed to the IPC layer as part of a message, or else it will leak.
     75 IPC_MESSAGE_SUPPORT_EXPORT PlatformFileForTransit
     76 GetPlatformFileForTransit(base::PlatformFile file, bool close_source_handle);
     77 
     78 // Creates a new handle that can be passed through IPC. The result must be
     79 // passed to the IPC layer as part of a message, or else it will leak.
     80 // Note that this function takes ownership of |file|.
     81 IPC_MESSAGE_SUPPORT_EXPORT PlatformFileForTransit
     82 TakePlatformFileForTransit(base::File file);
     83 
     84 }  // namespace IPC
     85 
     86 #endif  // IPC_IPC_PLATFORM_FILE_H_
     87