Mojo: POSIX: Add a PlatformChannelSendmsgWithHandles().

mojo/embedder/platform_channel_utils_posix.h

 // Copyright 2014 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 MOJO_EMBEDDER_PLATFORM_CHANNEL_UTILS_POSIX_H_
 #define MOJO_EMBEDDER_PLATFORM_CHANNEL_UTILS_POSIX_H_
 
 #include <stddef.h>
 #include <sys/types.h>  // For |ssize_t|.
 
 #include <deque>
 
 #include "base/memory/scoped_ptr.h"
 #include "mojo/embedder/platform_handle.h"
 #include "mojo/system/system_impl_export.h"
 
 struct iovec;  // Declared in <sys/uio.h>.
 
 namespace mojo {
 namespace embedder {
 
 // The maximum number of handles that can be sent "at once" using
-// |PlatformChannelSendHandles()|.
+// |PlatformChannelSendmsgWithHandles()|.
 // TODO(vtl): This number is taken from ipc/file_descriptor_set_posix.h:
 // |FileDescriptorSet::kMaxDescriptorsPerMessage|. Where does it come from?
 const size_t kPlatformChannelMaxNumHandles = 7;
 
 // Use these to write to a socket created using |PlatformChannelPair| (or
 // equivalent). These are like |write()| and |writev()|, but handle |EINTR| and
 // never raise |SIGPIPE|. (Note: On Mac, the suppression of |SIGPIPE| is set up
 // by |PlatformChannelPair|.)
 MOJO_SYSTEM_IMPL_EXPORT ssize_t PlatformChannelWrite(PlatformHandle h,
                                                      const void* bytes,
                                                      size_t num_bytes);
 MOJO_SYSTEM_IMPL_EXPORT ssize_t PlatformChannelWritev(PlatformHandle h,
                                                       struct iovec* iov,
                                                       size_t num_iov);
 
+// Writes data, and the given set of |PlatformHandle|s (i.e., file descriptors)
+// over the Unix domain socket given by |h| (e.g., created using
+// |PlatformChannelPair()|). All the handles must be valid, and there must be at
+// least one and at most |kPlatformChannelMaxNumHandles| handles. The return
+// value is as for |sendmsg()|, namely -1 on failure and otherwise the number of
+// bytes of data sent on success (note that this may not be all the data
+// specified by |iov|). (The handles are not closed, regardless of success or
+// failure.)
+MOJO_SYSTEM_IMPL_EXPORT ssize_t PlatformChannelSendmsgWithHandles(
+    PlatformHandle h,
+    struct iovec* iov,
+    size_t num_iov,
+    PlatformHandle* platform_handles,
+    size_t num_platform_handles);
+
+// TODO(vtl): Remove this once I've switched things over to
+// |PlatformChannelSendmsgWithHandles()|.
 // Sends |PlatformHandle|s (i.e., file descriptors) over the Unix domain socket
 // (e.g., created using PlatformChannelPair|). (These will be sent in a single
 // message having one null byte of data and one control message header with all
 // the file descriptors.) All of the handles must be valid, and there must be at
 // most |kPlatformChannelMaxNumHandles| (and at least one handle). Returns true
 // on success, in which case it closes all the handles.
 MOJO_SYSTEM_IMPL_EXPORT bool PlatformChannelSendHandles(PlatformHandle h,
                                                         PlatformHandle* handles,
                                                         size_t num_handles);
 
 // Wrapper around |recvmsg()|, which will extract any attached file descriptors
 // (in the control message) to |PlatformHandle|s (and append them to
 // |platform_handles|). (This also handles |EINTR|.)
 MOJO_SYSTEM_IMPL_EXPORT ssize_t PlatformChannelRecvmsg(
     PlatformHandle h,
     void* buf,
     size_t num_bytes,
     std::deque<PlatformHandle>* platform_handles);
 
 }  // namespace embedder
 }  // namespace mojo
 
 #endif  // MOJO_EMBEDDER_PLATFORM_CHANNEL_UTILS_POSIX_H_