Changing SpawnChild to return a struct.

mojo/edk/system/message_pipe_dispatcher.cc

 // Copyright 2015 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.
 
 #include "mojo/edk/system/message_pipe_dispatcher.h"
 
 #include <limits>
 #include <memory>
 
 #include "base/logging.h"
@@ skipping 268 matching lines @@
   // that it specifies a size at least as large as the next available payload.
   //
   // If |read_any_size| is true, the input value of |*num_bytes| is ignored.
   // This flag exists to support both new and old API behavior.
 
   ports::ScopedMessage ports_message;
   ReadMessageFilter filter(read_any_size, may_discard, num_bytes, num_handles,
                            &no_space, &invalid_message);
   int rv = node_controller_->node()->GetMessage(port_, &ports_message, &filter);
 
-  if (invalid_message)
+  if (invalid_message) {
+    NOTREACHED();
     return MOJO_RESULT_UNKNOWN;
+  }
 
   if (rv != ports::OK && rv != ports::ERROR_PORT_PEER_CLOSED) {
     if (rv == ports::ERROR_PORT_UNKNOWN ||
         rv == ports::ERROR_PORT_STATE_UNEXPECTED)
       return MOJO_RESULT_INVALID_ARGUMENT;
 
     NOTREACHED();
     return MOJO_RESULT_UNKNOWN;  // TODO: Add a better error code here?
   }
 
@@ skipping 19 matching lines @@
   // in which to receive it.
 
   std::unique_ptr<PortsMessage> msg(
       static_cast<PortsMessage*>(ports_message.release()));
 
   const MessageHeader* header =
       static_cast<const MessageHeader*>(msg->payload_bytes());
   const DispatcherHeader* dispatcher_headers =
       reinterpret_cast<const DispatcherHeader*>(header + 1);
 
-  if (header->num_dispatchers > std::numeric_limits<uint16_t>::max())
+  if (header->num_dispatchers > std::numeric_limits<uint16_t>::max()) {
+    NOTREACHED();
     return MOJO_RESULT_UNKNOWN;
+  }
 
   // Deserialize dispatchers.
   if (header->num_dispatchers > 0) {
     CHECK(handles);
     std::vector<DispatcherInTransit> dispatchers(header->num_dispatchers);
     size_t data_payload_index = sizeof(MessageHeader) +
         header->num_dispatchers * sizeof(DispatcherHeader);
-    if (data_payload_index > header->header_size)
+    if (data_payload_index > header->header_size) {
+      NOTREACHED();
       return MOJO_RESULT_UNKNOWN;
+    }
     const char* dispatcher_data = reinterpret_cast<const char*>(
         dispatcher_headers + header->num_dispatchers);
     size_t port_index = 0;
     size_t platform_handle_index = 0;
     ScopedPlatformHandleVectorPtr msg_handles = msg->TakeHandles();
     const size_t num_msg_handles = msg_handles ? msg_handles->size() : 0;
     for (size_t i = 0; i < header->num_dispatchers; ++i) {
       const DispatcherHeader& dh = dispatcher_headers[i];
       Type type = static_cast<Type>(dh.type);
 
       size_t next_payload_index = data_payload_index + dh.num_bytes;
       if (msg->num_payload_bytes() < next_payload_index ||
           next_payload_index < data_payload_index) {
+        NOTREACHED();
         return MOJO_RESULT_UNKNOWN;
       }
 
       size_t next_port_index = port_index + dh.num_ports;
-      if (msg->num_ports() < next_port_index || next_port_index < port_index)
+      if (msg->num_ports() < next_port_index || next_port_index < port_index) {
+        NOTREACHED();
         return MOJO_RESULT_UNKNOWN;
+      }
 
       size_t next_platform_handle_index =
           platform_handle_index + dh.num_platform_handles;
       if (num_msg_handles < next_platform_handle_index ||
           next_platform_handle_index < platform_handle_index) {
+        NOTREACHED();
         return MOJO_RESULT_UNKNOWN;
       }
 
       PlatformHandle* out_handles =
           num_msg_handles ? msg_handles->data() + platform_handle_index
                           : nullptr;
       dispatchers[i].dispatcher = Dispatcher::Deserialize(
           type, dispatcher_data, dh.num_bytes, msg->ports() + port_index,
           dh.num_ports, out_handles, dh.num_platform_handles);
-      if (!dispatchers[i].dispatcher)
+      if (!dispatchers[i].dispatcher) {
+        NOTREACHED();
         return MOJO_RESULT_UNKNOWN;
+      }
 
       dispatcher_data += dh.num_bytes;
       data_payload_index = next_payload_index;
       port_index = next_port_index;
       platform_handle_index = next_platform_handle_index;
     }
 
     if (!node_controller_->core()->AddDispatchersFromTransit(dispatchers,
-                                                             handles))
+                                                             handles)) {
+      NOTREACHED();
       return MOJO_RESULT_UNKNOWN;
+    }
   }
 
   CHECK(msg);
   *message = MessageForTransit::WrapPortsMessage(std::move(msg));
   return MOJO_RESULT_OK;
 }
 
 HandleSignalsState
 MessagePipeDispatcher::GetHandleSignalsState() const {
   base::AutoLock lock(signal_lock_);
@@ skipping 198 matching lines @@
                << " endpoint " << endpoint_ << " [port=" << port_.name() << "]";
     }
   }
 #endif
 
   awakables_.AwakeForStateChange(GetHandleSignalsStateNoLock());
 }
 
 }  // namespace edk
 }  // namespace mojo