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 class FileImpl;
  19 class PBlobParent;
  20
  21 } // namespace dom
  22
  23 namespace ipc {
  24
  25 class PBackgroundParent;
  26
  27 // This class is not designed for public consumption beyond the few static
  28 // member functions.
  29 class BackgroundParent MOZ_FINAL
  30 {
  31   friend class mozilla::dom::ContentParent;
  32
  33   typedef base::ProcessId ProcessId;
  34   typedef mozilla::dom::ContentParent ContentParent;
  35   typedef mozilla::dom::FileImpl FileImpl;
  36   typedef mozilla::ipc::Transport Transport;
  37
  38 public:
  39   // This function allows the caller to determine if the given parent actor
  40   // corresponds to a child actor from another process or a child actor from a
  41   // different thread in the same process.
  42   // This function may only be called on the background thread.
  43   static bool
  44   IsOtherProcessActor(PBackgroundParent* aBackgroundActor);
  45
  46   // This function returns the ContentParent associated with the parent actor if
  47   // the parent actor corresponds to a child actor from another process. If the
  48   // parent actor corresponds to a child actor from a different thread in the
  49   // same process then this function returns null.
  50   // This function may only be called on the background thread. However,
  51   // ContentParent is not threadsafe and the returned pointer may not be used on
  52   // any thread other than the main thread. Callers must take care to use (and
  53   // release) the returned pointer appropriately.
  54   static already_AddRefed<ContentParent>
  55   GetContentParent(PBackgroundParent* aBackgroundActor);
  56
  57   static mozilla::dom::PBlobParent*
  58   GetOrCreateActorForBlobImpl(PBackgroundParent* aBackgroundActor,
  59                               FileImpl* aBlobImpl);
  60
  61   // Get a value that represents the ContentParent associated with the parent
  62   // actor for comparison. The value is not guaranteed to uniquely identify the
  63   // ContentParent after the ContentParent has died. This function may only be
  64   // called on the background thread.
  65   static intptr_t
  66   GetRawContentParentForComparison(PBackgroundParent* aBackgroundActor);
  67
  68 private:
  69   // Only called by ContentParent for cross-process actors.
  70   static PBackgroundParent*
  71   Alloc(ContentParent* aContent,
  72         Transport* aTransport,
  73         ProcessId aOtherProcess);
  74 };
  75
  76 // Implemented in BackgroundImpl.cpp.
  77 bool
  78 IsOnBackgroundThread();
  79
  80 #ifdef DEBUG
  81
  82 // Implemented in BackgroundImpl.cpp.
  83 void
  84 AssertIsOnBackgroundThread();
  85
  86 #else
  87
  88 inline void
  89 AssertIsOnBackgroundThread()
  90 { }
  91
  92 #endif // DEBUG
  93
  94 } // namespace ipc
  95 } // namespace mozilla
  96
  97 #endif // mozilla_ipc_backgroundparent_h__