Adds Mojo IDL.

third_party/WebKit/Source/core/mojo/MojoHandle.cpp

+// Copyright 2017 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 "core/mojo/MojoHandle.h"
+
+#include "bindings/core/v8/ArrayBufferOrArrayBufferView.h"
+#include "bindings/core/v8/ScriptState.h"
+#include "core/dom/DOMArrayBuffer.h"
+#include "core/dom/DOMArrayBufferView.h"
+#include "core/mojo/MojoReadMessageFlags.h"
+#include "core/mojo/MojoReadMessageResult.h"
+#include "core/mojo/MojoWatcher.h"
+
+// Mojo messages typically do not contain many handles. In fact most
+// messages do not contain any handle. An inline capacity of 4 should avoid
+// heap allocation in vast majority of cases.
+static const size_t kHandleVectorInlineCapacity = 4;
+
+namespace blink {
+
+MojoHandle* MojoHandle::create(mojo::ScopedHandle handle) {
+  return new MojoHandle(std::move(handle));
+}
+
+MojoHandle::MojoHandle(mojo::ScopedHandle handle)
+    : m_handle(std::move(handle)) {}
+
+void MojoHandle::close() {
+  m_handle.reset();
+}
+
+MojoWatcher* MojoHandle::watch(ScriptState* scriptState,
+                               const MojoHandleSignals& signals,
+                               MojoWatchCallback* callback) {
+  return MojoWatcher::create(m_handle.get(), signals, callback,
+                             scriptState->getExecutionContext());
+}
+
+MojoResult MojoHandle::writeMessage(
+    ArrayBufferOrArrayBufferView& buffer,
+    const HeapVector<Member<MojoHandle>>& handles) {
+  // MojoWriteMessage takes ownership of the handles, so release them here.
+  Vector<::MojoHandle, kHandleVectorInlineCapacity> rawHandles(handles.size());
+  std::transform(
+      handles.begin(), handles.end(), rawHandles.begin(),
+      [](MojoHandle* handle) { return handle->m_handle.release().value(); });
+
+  const void* bytes = nullptr;
+  uint32_t numBytes = 0;
+  if (buffer.isArrayBuffer()) {
+    DOMArrayBuffer* array = buffer.getAsArrayBuffer();
+    bytes = array->data();
+    numBytes = array->byteLength();
+  } else {
+    DOMArrayBufferView* view = buffer.getAsArrayBufferView();
+    bytes = view->baseAddress();
+    numBytes = view->byteLength();
+  }
+
+  return MojoWriteMessage(m_handle->value(), bytes, numBytes, rawHandles.data(),
+                          rawHandles.size(), MOJO_WRITE_MESSAGE_FLAG_NONE);
+}
+
+void MojoHandle::readMessage(const MojoReadMessageFlags& flagsDict,
+                             MojoReadMessageResult& resultDict) {
+  ::MojoReadMessageFlags flags = MOJO_READ_MESSAGE_FLAG_NONE;
+  if (flagsDict.mayDiscard())
+    flags |= MOJO_READ_MESSAGE_FLAG_MAY_DISCARD;
+
+  uint32_t numBytes = 0, numHandles = 0;
+  MojoResult result = MojoReadMessage(m_handle->value(), nullptr, &numBytes,
+                                      nullptr, &numHandles, flags);
+  if (result != MOJO_RESULT_RESOURCE_EXHAUSTED) {
+    resultDict.setResult(result);
+    return;
+  }
+
+  DOMArrayBuffer* buffer = DOMArrayBuffer::createUninitialized(numBytes, 1);
+  Vector<::MojoHandle, kHandleVectorInlineCapacity> rawHandles(numHandles);
+  result = MojoReadMessage(m_handle->value(), buffer->data(), &numBytes,
+                           rawHandles.data(), &numHandles, flags);
+
+  HeapVector<Member<MojoHandle>> handles(numHandles);
+  for (size_t i = 0; i < numHandles; ++i) {
+    handles[i] =
+        MojoHandle::create(mojo::MakeScopedHandle(mojo::Handle(rawHandles[i])));
+  }
+
+  resultDict.setResult(result);
+  resultDict.setBuffer(buffer);
+  resultDict.setHandles(handles);
+}
+
+}  // namespace blink