Mojo: Make MessageInTransit more opaque still.

mojo/system/raw_channel_posix_unittest.cc

 // Copyright 2013 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.
 
 // TODO(vtl): Factor out the remaining POSIX-specific bits of this test (once we
 // have a non-POSIX implementation).
 
 #include "mojo/system/raw_channel.h"
 
 #include <fcntl.h>
@@ skipping 127 matching lines @@
           read(handle_.fd, buffer, sizeof(buffer)));
       if (read_size < 0) {
         PCHECK(errno == EAGAIN || errno == EWOULDBLOCK);
         read_size = 0;
       }
 
       // Append newly-read data to |bytes_|.
       bytes_.insert(bytes_.end(), buffer, buffer + read_size);
 
       // If we have the header....
-      if (bytes_.size() >= sizeof(MessageInTransit)) {
-        const MessageInTransit* message =
-            reinterpret_cast<const MessageInTransit*>(bytes_.data());
-        CHECK_EQ(reinterpret_cast<size_t>(message) %
-                     MessageInTransit::kMessageAlignment, 0u);
+      size_t message_size;
+      if (MessageInTransit::GetNextMessageSize(bytes_.data(), bytes_.size(),
+                                               &message_size)) {
+        // If we've read the whole message....
+        if (bytes_.size() >= message_size) {
+          const MessageInTransit* message =
+              MessageInTransit::CreateReadOnlyFromBuffer(bytes_.data());
+          CHECK_EQ(message->main_buffer_size(), message_size);
 
-        if (message->data_size() != expected_size) {
-          LOG(ERROR) << "Wrong size: " << message->data_size() << " instead of "
-                     << expected_size << " bytes.";
-          return false;
-        }
+          if (message->data_size() != expected_size) {
+            LOG(ERROR) << "Wrong size: " << message_size << " instead of "
+                       << expected_size << " bytes.";
+            return false;
+          }
 
-        // If we've read the whole message....
-        if (bytes_.size() >= message->main_buffer_size()) {
           if (!CheckMessageData(message->data(), message->data_size())) {
             LOG(ERROR) << "Incorrect message data.";
             return false;
           }
 
           // Erase message data.
           bytes_.erase(bytes_.begin(),
                        bytes_.begin() +
                            message->main_buffer_size());
           return true;
@@ skipping 374 matching lines @@
                         FROM_HERE,
                         base::Bind(&RawChannel::Shutdown,
                                    base::Unretained(rc.get())));
 
   EXPECT_FALSE(rc->WriteMessage(MakeTestMessage(1)));
 }
 
 }  // namespace
 }  // namespace system
 }  // namespace mojo