Stub in more IPC attachment brokering functionality.

ipc/ipc_message_attachment_set.h

 // Copyright (c) 2011 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 IPC_IPC_MESSAGE_ATTACHMENT_SET_H_
 #define IPC_IPC_MESSAGE_ATTACHMENT_SET_H_
 
 #include <vector>
 
 #include "base/basictypes.h"
 #include "base/memory/ref_counted.h"
 #include "base/memory/scoped_vector.h"
 #include "ipc/ipc_export.h"
 
 #if defined(OS_POSIX)
 #include "base/files/file.h"
 #endif
 
 namespace IPC {
 
+class BrokerableAttachment;
 class MessageAttachment;
 
 // -----------------------------------------------------------------------------
 // A MessageAttachmentSet is an ordered set of MessageAttachment objects. These
 // are associated with IPC messages so that attachments, each of which is either
 // a platform file or a mojo handle, can be transmitted over the underlying UNIX
 // domain socket (for ChannelPosix) or Mojo MessagePipe (for ChannelMojo).
 // -----------------------------------------------------------------------------
 class IPC_EXPORT MessageAttachmentSet
     : public base::RefCountedThreadSafe<MessageAttachmentSet> {
  public:
   MessageAttachmentSet();
 
   // Return the number of attachments
   unsigned size() const;
   // Return the number of file descriptors
   unsigned num_descriptors() const;
   // Return the number of mojo handles in the attachment set
   unsigned num_mojo_handles() const;
+  // Return the number of brokerable attachments in the attachment set.
+  unsigned num_brokerable_attachments() const;
 
   // Return true if no unconsumed descriptors remain
   bool empty() const { return 0 == size(); }
 
   bool AddAttachment(scoped_refptr<MessageAttachment> attachment);
 
   // Take the nth attachment from the beginning of the set, Code using this
   // /must/ access the attachments in order, and must do it at most once.
   //
   // This interface is designed for the deserialising code as it doesn't
   // support close flags.
   //   returns: an attachment, or nullptr on error
   scoped_refptr<MessageAttachment> GetAttachmentAt(unsigned index);
 
   // This must be called after transmitting the descriptors returned by
   // PeekDescriptors. It marks all the descriptors as consumed and closes those
   // which are auto-close.
   void CommitAll();
 
+  // Returns a vector of all brokerable attachments.
+  std::vector<const BrokerableAttachment*> PeekBrokerableAttachments() const;
+
 #if defined(OS_POSIX)
   // This is the maximum number of descriptors per message. We need to know this
   // because the control message kernel interface has to be given a buffer which
   // is large enough to store all the descriptor numbers. Otherwise the kernel
   // tells us that it truncated the control data and the extra descriptors are
   // lost.
   //
   // In debugging mode, it's a fatal error to try and add more than this number
   // of descriptors to a MessageAttachmentSet.
   static const size_t kMaxDescriptorsPerMessage = 7;
@@ skipping 40 matching lines @@
   // all the descriptors have been read (with GetNthDescriptor). Secondly, we
   // can check that they are read in order.
   mutable unsigned consumed_descriptor_highwater_;
 
   DISALLOW_COPY_AND_ASSIGN(MessageAttachmentSet);
 };
 
 }  // namespace IPC
 
 #endif  // IPC_IPC_MESSAGE_ATTACHMENT_SET_H_