ipc/glue/BackgroundParent.h

   1 /* This Source Code Form is subject to the terms of the Mozilla Public
   2  * License, v. 2.0. If a copy of the MPL was not distributed with this file,
   3  * You can obtain one at http://mozilla.org/MPL/2.0/. */
   4
   5 #ifndef mozilla_ipc_backgroundparent_h__
   6 #define mozilla_ipc_backgroundparent_h__
   7
   8 #include "base/process.h"
   9 #include "mozilla/Attributes.h"
  10 #include "mozilla/ipc/Transport.h"
  11
  12 template <class> struct already_AddRefed;
  13
  14 namespace mozilla {
  15 namespace dom {
  16
  17 class ContentParent;
  18
  19 } // namespace dom
  20
  21 namespace ipc {
  22
  23 class PBackgroundParent;
  24
  25 // This class is not designed for public consumption beyond the few static
  26 // member functions.
  27 class BackgroundParent MOZ_FINAL
  28 {
  29   friend class mozilla::dom::ContentParent;
  30
  31   typedef base::ProcessId ProcessId;
  32   typedef mozilla::dom::ContentParent ContentParent;
  33   typedef mozilla::ipc::Transport Transport;
  34
  35 public:
  36   // This function allows the caller to determine if the given parent actor
  37   // corresponds to a child actor from another process or a child actor from a
  38   // different thread in the same process.
  39   // This function may only be called on the background thread.
  40   static bool
  41   IsOtherProcessActor(PBackgroundParent* aBackgroundActor);
  42
  43   // This function returns the ContentParent associated with the parent actor if
  44   // the parent actor corresponds to a child actor from another process. If the
  45   // parent actor corresponds to a child actor from a different thread in the
  46   // same process then this function returns null.
  47   // This function may only be called on the background thread. However,
  48   // ContentParent is not threadsafe and the returned pointer may not be used on
  49   // any thread other than the main thread. Callers must take care to use (and
  50   // release) the returned pointer appropriately.
  51   static already_AddRefed<ContentParent>
  52   GetContentParent(PBackgroundParent* aBackgroundActor);
  53
  54 private:
  55   // Only called by ContentParent for cross-process actors.
  56   static PBackgroundParent*
  57   Alloc(ContentParent* aContent,
  58         Transport* aTransport,
  59         ProcessId aOtherProcess);
  60 };
  61
  62 // Implemented in BackgroundImpl.cpp.
  63 bool
  64 IsOnBackgroundThread();
  65
  66 #ifdef DEBUG
  67
  68 // Implemented in BackgroundImpl.cpp.
  69 void
  70 AssertIsOnBackgroundThread();
  71
  72 #else
  73
  74 inline void
  75 AssertIsOnBackgroundThread()
  76 { }
  77
  78 #endif // DEBUG
  79
  80 } // namespace ipc
  81 } // namespace mozilla
  82
  83 #endif // mozilla_ipc_backgroundparent_h__