Mojo JS bindings: draining a DataPipe

mojo/bindings/js/core.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 "mojo/bindings/js/core.h"
 
 #include "base/bind.h"
 #include "base/logging.h"
 #include "gin/arguments.h"
 #include "gin/array_buffer.h"
 #include "gin/converter.h"
 #include "gin/dictionary.h"
 #include "gin/function_template.h"
 #include "gin/handle.h"
 #include "gin/object_template_builder.h"
 #include "gin/per_isolate_data.h"
 #include "gin/public/wrapper_info.h"
 #include "gin/wrappable.h"
+#include "mojo/bindings/js/drain_data.h"
 #include "mojo/bindings/js/handle.h"
 
 namespace mojo {
 namespace js {
 
 namespace {
 
 MojoResult CloseHandle(gin::Handle<gin::HandleWrapper> handle) {
   if (!handle->get().is_valid())
     return MOJO_RESULT_INVALID_ARGUMENT;
@@ skipping 185 matching lines @@
 
   result = MojoReadData(handle.value(), buffer.bytes(), &num_bytes, flags);
   CHECK_EQ(num_bytes, buffer.num_bytes());
 
   gin::Dictionary dictionary = gin::Dictionary::CreateEmpty(args.isolate());
   dictionary.Set("result", result);
   dictionary.Set("buffer", array_buffer);
   return dictionary;
 }
 
+// Asynchronously read all of the data available for the specified data pipe
+// consumer handle until the remote handle is closed or an error occurs. A
+// Promise is returned whose settled value is an object like this:
+// {result: core.RESULT_OK, buffer: dataArrayBuffer}. If the read failed,
+// then the Promise is rejected, the result will be the actual error code,
+// and the buffer will contain whatever was read before the error occurred.
+// The drainData data pipe handle argument is closed automatically.
+
+v8::Handle<v8::Value> DoDrainData(gin::Arguments* args, mojo::Handle handle) {
+  return (new DrainData(args->isolate(), handle))->GetPromise();
+}
+
 gin::WrapperInfo g_wrapper_info = { gin::kEmbedderNativeGin };
 
 }  // namespace
 
 const char Core::kModuleName[] = "mojo/public/js/bindings/core";
 
 v8::Local<v8::Value> Core::GetModule(v8::Isolate* isolate) {
   gin::PerIsolateData* data = gin::PerIsolateData::From(isolate);
   v8::Local<v8::ObjectTemplate> templ = data->GetObjectTemplate(
       &g_wrapper_info);
 
   if (templ.IsEmpty()) {
      templ = gin::ObjectTemplateBuilder(isolate)
         // TODO(mpcomplete): Should these just be methods on the JS Handle
         // object?
         .SetMethod("close", CloseHandle)
         .SetMethod("wait", WaitHandle)
         .SetMethod("waitMany", WaitMany)
         .SetMethod("createMessagePipe", CreateMessagePipe)
         .SetMethod("writeMessage", WriteMessage)
         .SetMethod("readMessage", ReadMessage)
         .SetMethod("createDataPipe", CreateDataPipe)
         .SetMethod("writeData", WriteData)
         .SetMethod("readData", ReadData)
+        .SetMethod("drainData", DoDrainData)
 
         .SetValue("RESULT_OK", MOJO_RESULT_OK)
         .SetValue("RESULT_CANCELLED", MOJO_RESULT_CANCELLED)
         .SetValue("RESULT_UNKNOWN", MOJO_RESULT_UNKNOWN)
         .SetValue("RESULT_INVALID_ARGUMENT", MOJO_RESULT_INVALID_ARGUMENT)
         .SetValue("RESULT_DEADLINE_EXCEEDED", MOJO_RESULT_DEADLINE_EXCEEDED)
         .SetValue("RESULT_NOT_FOUND", MOJO_RESULT_NOT_FOUND)
         .SetValue("RESULT_ALREADY_EXISTS", MOJO_RESULT_ALREADY_EXISTS)
         .SetValue("RESULT_PERMISSION_DENIED", MOJO_RESULT_PERMISSION_DENIED)
         .SetValue("RESULT_RESOURCE_EXHAUSTED", MOJO_RESULT_RESOURCE_EXHAUSTED)
@@ skipping 39 matching lines @@
         .Build();
 
     data->SetObjectTemplate(&g_wrapper_info, templ);
   }
 
   return templ->NewInstance();
 }
 
 }  // namespace js
 }  // namespace mojo