PPAPI: Disallow blocking callbacks while handling a blocking message

ppapi/tests/test_message_handler.cc

 // 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.
 
 #include "ppapi/tests/test_message_handler.h"
 
 #include <string.h>
 #include <algorithm>
 #include <map>
 #include <sstream>
 
 #include "ppapi/c/pp_var.h"
 #include "ppapi/c/ppb_file_io.h"
 #include "ppapi/c/ppb_messaging.h"
 #include "ppapi/c/ppp_message_handler.h"
+#include "ppapi/cpp/completion_callback.h"
 #include "ppapi/cpp/file_io.h"
 #include "ppapi/cpp/file_ref.h"
 #include "ppapi/cpp/file_system.h"
 #include "ppapi/cpp/instance.h"
 #include "ppapi/cpp/message_handler.h"
 #include "ppapi/cpp/module_impl.h"
+#include "ppapi/cpp/network_list.h"
+#include "ppapi/cpp/network_monitor.h"
 #include "ppapi/cpp/var.h"
 #include "ppapi/cpp/var_array.h"
 #include "ppapi/cpp/var_array_buffer.h"
 #include "ppapi/cpp/var_dictionary.h"
 #include "ppapi/tests/pp_thread.h"
 #include "ppapi/tests/test_utils.h"
 #include "ppapi/tests/testing_instance.h"
 
 // Windows defines 'PostMessage', so we have to undef it.
 #ifdef PostMessage
@@ skipping 83 matching lines @@
       testing_instance_->PostMessage(var);
   }
 
   virtual pp::Var HandleBlockingMessage(pp::InstanceHandle instance,
                                         const pp::Var& var) {
     if (pp::MessageLoop::GetCurrent() != message_handler_loop_)
       AddError("HandleBlockingMessage was called on the wrong thread!");
     if (instance.pp_instance() != testing_instance_->pp_instance())
       AddError("HandleBlockingMessage was passed the wrong instance!");
 
+    // Attempt a blocking operation; make sure it's disallowed.
+    pp::NetworkMonitor monitor(instance);
+    PP_Resource out_param = 0;
+    pp::CompletionCallbackWithOutput<pp::NetworkList> blocking_callback(
+        &out_param);
+    int32_t error = monitor.UpdateNetworkList(blocking_callback);
+    if (error != PP_ERROR_WOULD_BLOCK_THREAD) {
+      AddError("HandleBlockingMessage was allowed to do a blocking call!");
+      pp::Module::Get()->core()->ReleaseResource(out_param);
+    }
+
     return var;
   }
 
   virtual void WasUnregistered(pp::InstanceHandle instance) {
     if (pp::MessageLoop::GetCurrent() != message_handler_loop_)
       AddError("Destroy was called on the wrong thread!");
     if (instance.pp_instance() != testing_instance_->pp_instance())
       AddError("Destroy was passed the wrong instance!");
     destroy_event_.Signal();
   }
@@ skipping 124 matching lines @@
   // That should be fixed before this API goes to stable. See crbug.com/384528
   js_code += "plugin.postMessage('FINISHED_TEST');\n";
   instance_->EvalScript(js_code);
   handler.WaitForTestFinishedMessage();
   handler.Unregister();
   ASSERT_SUBTEST_SUCCESS(handler.WaitForDestroy());
 
   PASS();
 }