IPC::Message Refactoring: Move POSIX specific bits to PlatformFileAttachment

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 MessageAttachment;
 
 // -----------------------------------------------------------------------------
-// A MessageAttachmentSet is an ordered set of POSIX file descriptors. These are
-// associated with IPC messages so that descriptors can be transmitted over a
-// UNIX domain socket.
+// 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 underlying UNIX

[agl, 2015/01/30 19:34:02]

"the" before "underlying"

[Hajime Morrita, 2015/01/30 21:01:29]

Done.

+// 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 true if no unconsumed descriptors remain
   bool empty() const { return 0 == size(); }
 
-  void AddAttachment(scoped_refptr<MessageAttachment> attachment);
+  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 attachments, or nullptr on error

[agl, 2015/01/30 19:34:02]

s/attachments/attachment/

[Hajime Morrita, 2015/01/30 21:01:29]

Done.

   scoped_refptr<MessageAttachment> GetAttachmentAt(unsigned index);
 
 #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;
 
   // ---------------------------------------------------------------------------
-  // Interfaces for building during message serialisation...
-
-  // Add a descriptor to the end of the set. Returns false iff the set is full.
-  bool AddToBorrow(base::PlatformFile fd);
-  // Add a descriptor to the end of the set and automatically close it after
-  // transmission. Returns false iff the set is full.
-  bool AddToOwn(base::ScopedFD fd);
-
-  // ---------------------------------------------------------------------------
-  // ---------------------------------------------------------------------------
-  // Interfaces for accessing during message deserialisation...
-
-  // Take the nth descriptor from the beginning of the set,
-  // transferring the ownership of the descriptor taken. Code using this
-  // /must/ access the descriptors 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: file descriptor, or -1 on error
-  base::PlatformFile TakeDescriptorAt(unsigned n);
-
-  // ---------------------------------------------------------------------------
-
-  // ---------------------------------------------------------------------------
   // Interfaces for transmission...
 
   // Fill an array with file descriptors without 'consuming' them. CommitAll
   // must be called after these descriptors have been transmitted.
   //   buffer: (output) a buffer of, at least, size() integers.
   void PeekDescriptors(base::PlatformFile* buffer) const;
   // 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();
@@ skipping 20 matching lines @@
 
  private:
   friend class base::RefCountedThreadSafe<MessageAttachmentSet>;
 
   ~MessageAttachmentSet();
 
   // A vector of attachments of the message, which might be |PlatformFile| or
   // |MessagePipe|.
   std::vector<scoped_refptr<MessageAttachment>> attachments_;
 
-#if defined(OS_POSIX)
-  // A vector of owning descriptors. If this message is sent, then file
-  // descriptors are sent as control data. After sending, any owning descriptors
-  // are closed. If this message has been received then all received
-  // descriptors are owned by this message.
-  ScopedVector<base::ScopedFD> owned_descriptors_;
-#endif
-
   // This contains the index of the next descriptor which should be consumed.
   // It's used in a couple of ways. Firstly, at destruction we can check that
   // 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_