Move getBufferSubDataAsync to an extension

third_party/WebKit/Source/modules/webgl/WebGLGetBufferSubDataAsync.cpp

+// Copyright 2016 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 "modules/webgl/WebGLGetBufferSubDataAsync.h"
+
+#include "core/dom/DOMException.h"
+#include "gpu/GLES2/gl2extchromium.h"
+#include "gpu/command_buffer/client/gles2_interface.h"
+#include "modules/webgl/WebGL2RenderingContextBase.h"
+
+namespace blink {
+
+WebGLGetBufferSubDataAsync::WebGLGetBufferSubDataAsync(
+    WebGLRenderingContextBase* context)
+    : WebGLExtension(context) {}
+
+WebGLExtensionName WebGLGetBufferSubDataAsync::name() const {
+  return WebGLGetBufferSubDataAsyncName;
+}
+
+WebGLGetBufferSubDataAsync* WebGLGetBufferSubDataAsync::create(
+    WebGLRenderingContextBase* context) {
+  return new WebGLGetBufferSubDataAsync(context);
+}
+
+bool WebGLGetBufferSubDataAsync::supported(WebGLRenderingContextBase* context) {
+  return true;
+}
+
+const char* WebGLGetBufferSubDataAsync::extensionName() {
+  return "WEBGL_get_buffer_sub_data_async";
+}
+
+ScriptPromise WebGLGetBufferSubDataAsync::getBufferSubDataAsync(
+    ScriptState* scriptState,
+    GLenum target,
+    GLintptr srcByteOffset,
+    DOMArrayBufferView* dstData,
+    GLuint dstOffset,
+    GLuint length) {
+  ScriptPromiseResolver* resolver = ScriptPromiseResolver::create(scriptState);
+  ScriptPromise promise = resolver->promise();
+
+  WebGLExtensionScopedContext scoped(this);
+  if (scoped.isLost()) {
+    DOMException* exception =
+        DOMException::create(InvalidStateError, "context lost");
+    resolver->reject(exception);
+    return promise;
+  }
+
+  WebGL2RenderingContextBase* context = nullptr;
+  {
+    WebGLRenderingContextBase* contextBase = scoped.context();
+    DCHECK_GE(contextBase->version(), 2u);
+    context = static_cast<WebGL2RenderingContextBase*>(contextBase);
+  }
+
+  WebGLBuffer* sourceBuffer = nullptr;
+  void* destinationDataPtr = nullptr;
+  long long destinationByteLength = 0;
+  const char* message = context->validateGetBufferSubData(
+      __FUNCTION__, target, srcByteOffset, dstData, dstOffset, length,
+      &sourceBuffer, &destinationDataPtr, &destinationByteLength);
+  if (message) {
+    // If there was a GL error, it was already synthesized in
+    // validateGetBufferSubData, so it's not done here.
+    DOMException* exception = DOMException::create(InvalidStateError, message);
+    resolver->reject(exception);
+    return promise;
+  }
+
+  message = context->validateGetBufferSubDataBounds(
+      __FUNCTION__, sourceBuffer, srcByteOffset, destinationByteLength);
+  if (message) {
+    // If there was a GL error, it was already synthesized in
+    // validateGetBufferSubDataBounds, so it's not done here.
+    DOMException* exception = DOMException::create(InvalidStateError, message);
+    resolver->reject(exception);
+    return promise;
+  }
+
+  // If the length of the copy is zero, this is a no-op.
+  if (!destinationByteLength) {
+    resolver->resolve(dstData);
+    return promise;
+  }
+
+  GLuint queryID;
+  context->contextGL()->GenQueriesEXT(1, &queryID);
+  context->contextGL()->BeginQueryEXT(GL_COMMANDS_ISSUED_CHROMIUM, queryID);
+  void* mappedData = context->contextGL()->GetBufferSubDataAsyncCHROMIUM(
+      target, srcByteOffset, destinationByteLength);
+  context->contextGL()->EndQueryEXT(GL_COMMANDS_ISSUED_CHROMIUM);
+  if (!mappedData) {
+    DOMException* exception =
+        DOMException::create(InvalidStateError, "Out of memory");
+    resolver->reject(exception);
+    return promise;
+  }
+
+  auto callbackObject = new WebGLGetBufferSubDataAsyncCallback(
+      context, resolver, mappedData, queryID, dstData, destinationDataPtr,
+      destinationByteLength);
+  context->registerGetBufferSubDataAsyncCallback(callbackObject);
+  auto callback = WTF::bind(&WebGLGetBufferSubDataAsyncCallback::resolve,
+                            wrapPersistent(callbackObject));
+  context->drawingBuffer()->contextProvider()->signalQuery(
+      queryID, convertToBaseCallback(std::move(callback)));
+
+  return promise;
+}
+
+WebGLGetBufferSubDataAsyncCallback::WebGLGetBufferSubDataAsyncCallback(
+    WebGL2RenderingContextBase* context,
+    ScriptPromiseResolver* promiseResolver,
+    void* shmReadbackResultData,
+    GLuint commandsIssuedQueryID,
+    DOMArrayBufferView* destinationArrayBufferView,
+    void* destinationDataPtr,
+    long long destinationByteLength)
+    : m_context(context),
+      m_promiseResolver(promiseResolver),
+      m_shmReadbackResultData(shmReadbackResultData),
+      m_commandsIssuedQueryID(commandsIssuedQueryID),
+      m_destinationArrayBufferView(destinationArrayBufferView),
+      m_destinationDataPtr(destinationDataPtr),
+      m_destinationByteLength(destinationByteLength) {
+  DCHECK(shmReadbackResultData);
+  DCHECK(destinationDataPtr);
+}
+
+void WebGLGetBufferSubDataAsyncCallback::destroy() {
+  DCHECK(m_shmReadbackResultData);
+  m_context->contextGL()->FreeSharedMemory(m_shmReadbackResultData);
+  m_shmReadbackResultData = nullptr;
+  DOMException* exception =
+      DOMException::create(InvalidStateError, "Context lost or destroyed");
+  m_promiseResolver->reject(exception);
+}
+
+void WebGLGetBufferSubDataAsyncCallback::resolve() {
+  if (!m_context || !m_shmReadbackResultData) {
+    DOMException* exception =
+        DOMException::create(InvalidStateError, "Context lost or destroyed");
+    m_promiseResolver->reject(exception);
+    return;
+  }
+  if (m_destinationArrayBufferView->buffer()->isNeutered()) {
+    DOMException* exception = DOMException::create(
+        InvalidStateError, "ArrayBufferView became invalid asynchronously");
+    m_promiseResolver->reject(exception);
+    return;
+  }
+  memcpy(m_destinationDataPtr, m_shmReadbackResultData,
+         m_destinationByteLength);
+  // TODO(kainino): What would happen if the DOM was suspended when the
+  // promise became resolved? Could another JS task happen between the memcpy
+  // and the promise resolution task, which would see the wrong data?
+  m_promiseResolver->resolve(m_destinationArrayBufferView);
+
+  m_context->contextGL()->DeleteQueriesEXT(1, &m_commandsIssuedQueryID);
+  this->destroy();
+  m_context->unregisterGetBufferSubDataAsyncCallback(this);
+}
+
+DEFINE_TRACE(WebGLGetBufferSubDataAsyncCallback) {
+  visitor->trace(m_context);
+  visitor->trace(m_promiseResolver);
+  visitor->trace(m_destinationArrayBufferView);
+}
+
+}  // namespace blink