1 files changed, 321 insertions, 0 deletions
diff --git a/dom/canvas/CanvasRenderingContextHelper.cpp b/dom/canvas/CanvasRenderingContextHelper.cpp
new file mode 100644
index 0000000000..d45ad8883e
--- /dev/null
+++ b/dom/canvas/CanvasRenderingContextHelper.cpp
@@ -0,0 +1,321 @@
+/* -*- Mode: C++; tab-width: 2; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+#include "CanvasRenderingContextHelper.h"
+#include "GLContext.h"
+#include "ImageBitmapRenderingContext.h"
+#include "ImageEncoder.h"
+#include "mozilla/dom/BlobImpl.h"
+#include "mozilla/dom/CanvasRenderingContext2D.h"
+#include "mozilla/dom/OffscreenCanvasRenderingContext2D.h"
+#include "mozilla/GfxMessageUtils.h"
+#include "mozilla/Telemetry.h"
+#include "mozilla/UniquePtr.h"
+#include "mozilla/webgpu/CanvasContext.h"
+#include "MozFramebuffer.h"
+#include "nsContentUtils.h"
+#include "nsDOMJSUtils.h"
+#include "nsIScriptContext.h"
+#include "nsJSUtils.h"
+#include "ClientWebGLContext.h"
+
+namespace mozilla::dom {
+
+CanvasRenderingContextHelper::CanvasRenderingContextHelper()
+    : mCurrentContextType(CanvasContextType::NoContext) {}
+
+void CanvasRenderingContextHelper::ToBlob(
+    JSContext* aCx, nsIGlobalObject* aGlobal, BlobCallback& aCallback,
+    const nsAString& aType, JS::Handle<JS::Value> aParams, bool aUsePlaceholder,
+    ErrorResult& aRv) {
+  // Encoder callback when encoding is complete.
+  class EncodeCallback : public EncodeCompleteCallback {
+   public:
+    EncodeCallback(nsIGlobalObject* aGlobal, BlobCallback* aCallback)
+        : mGlobal(aGlobal), mBlobCallback(aCallback) {}
+
+    // This is called on main thread.
+    MOZ_CAN_RUN_SCRIPT
+    nsresult ReceiveBlobImpl(already_AddRefed<BlobImpl> aBlobImpl) override {
+      MOZ_ASSERT(NS_IsMainThread());
+
+      RefPtr<BlobImpl> blobImpl = aBlobImpl;
+
+      RefPtr<Blob> blob;
+
+      if (blobImpl) {
+        blob = Blob::Create(mGlobal, blobImpl);
+      }
+
+      RefPtr<BlobCallback> callback(std::move(mBlobCallback));
+      ErrorResult rv;
+
+      callback->Call(blob, rv);
+
+      mGlobal = nullptr;
+      MOZ_ASSERT(!mBlobCallback);
+
+      return rv.StealNSResult();
+    }
+
+    bool CanBeDeletedOnAnyThread() override {
+      // EncodeCallback is used from the main thread only.
+      return false;
+    }
+
+    nsCOMPtr<nsIGlobalObject> mGlobal;
+    RefPtr<BlobCallback> mBlobCallback;
+  };
+
+  RefPtr<EncodeCompleteCallback> callback =
+      new EncodeCallback(aGlobal, &aCallback);
+
+  ToBlob(aCx, callback, aType, aParams, aUsePlaceholder, aRv);
+}
+
+void CanvasRenderingContextHelper::ToBlob(
+    JSContext* aCx, EncodeCompleteCallback* aCallback, const nsAString& aType,
+    JS::Handle<JS::Value> aParams, bool aUsePlaceholder, ErrorResult& aRv) {
+  nsAutoString type;
+  nsContentUtils::ASCIIToLower(aType, type);
+
+  nsAutoString params;
+  bool usingCustomParseOptions;
+  aRv = ParseParams(aCx, type, aParams, params, &usingCustomParseOptions);
+  if (aRv.Failed()) {
+    return;
+  }
+
+  ToBlob(aCallback, type, params, usingCustomParseOptions, aUsePlaceholder,
+         aRv);
+}
+
+void CanvasRenderingContextHelper::ToBlob(EncodeCompleteCallback* aCallback,
+                                          nsAString& aType,
+                                          const nsAString& aEncodeOptions,
+                                          bool aUsingCustomOptions,
+                                          bool aUsePlaceholder,
+                                          ErrorResult& aRv) {
+  const nsIntSize elementSize = GetWidthHeight();
+  if (mCurrentContext) {
+    // We disallow canvases of width or height zero, and set them to 1, so
+    // we will have a discrepancy with the sizes of the canvas and the context.
+    // That discrepancy is OK, the rest are not.
+    if ((elementSize.width != mCurrentContext->GetWidth() &&
+         (elementSize.width != 0 || mCurrentContext->GetWidth() != 1)) ||
+        (elementSize.height != mCurrentContext->GetHeight() &&
+         (elementSize.height != 0 || mCurrentContext->GetHeight() != 1))) {
+      aRv.Throw(NS_ERROR_FAILURE);
+      return;
+    }
+  }
+
+  UniquePtr<uint8_t[]> imageBuffer;
+  int32_t format = 0;
+  auto imageSize = gfx::IntSize{elementSize.width, elementSize.height};
+  if (mCurrentContext) {
+    imageBuffer = mCurrentContext->GetImageBuffer(&format, &imageSize);
+  }
+
+  RefPtr<EncodeCompleteCallback> callback = aCallback;
+
+  aRv = ImageEncoder::ExtractDataAsync(
+      aType, aEncodeOptions, aUsingCustomOptions, std::move(imageBuffer),
+      format, {imageSize.width, imageSize.height}, aUsePlaceholder, callback);
+}
+
+already_AddRefed<nsICanvasRenderingContextInternal>
+CanvasRenderingContextHelper::CreateContext(CanvasContextType aContextType) {
+  return CreateContextHelper(aContextType, layers::LayersBackend::LAYERS_NONE);
+}
+
+already_AddRefed<nsICanvasRenderingContextInternal>
+CanvasRenderingContextHelper::CreateContextHelper(
+    CanvasContextType aContextType, layers::LayersBackend aCompositorBackend) {
+  MOZ_ASSERT(aContextType != CanvasContextType::NoContext);
+  RefPtr<nsICanvasRenderingContextInternal> ret;
+
+  switch (aContextType) {
+    case CanvasContextType::NoContext:
+      break;
+
+    case CanvasContextType::Canvas2D:
+      Telemetry::Accumulate(Telemetry::CANVAS_2D_USED, 1);
+      ret = new CanvasRenderingContext2D(aCompositorBackend);
+      break;
+
+    case CanvasContextType::OffscreenCanvas2D:
+      Telemetry::Accumulate(Telemetry::CANVAS_2D_USED, 1);
+      ret = new OffscreenCanvasRenderingContext2D(aCompositorBackend);
+      break;
+
+    case CanvasContextType::WebGL1:
+      Telemetry::Accumulate(Telemetry::CANVAS_WEBGL_USED, 1);
+
+      ret = new ClientWebGLContext(/*webgl2:*/ false);
+
+      break;
+
+    case CanvasContextType::WebGL2:
+      Telemetry::Accumulate(Telemetry::CANVAS_WEBGL_USED, 1);
+
+      ret = new ClientWebGLContext(/*webgl2:*/ true);
+
+      break;
+
+    case CanvasContextType::WebGPU:
+      // TODO
+      // Telemetry::Accumulate(Telemetry::CANVAS_WEBGPU_USED, 1);
+
+      ret = new webgpu::CanvasContext();
+
+      break;
+
+    case CanvasContextType::ImageBitmap:
+      ret = new ImageBitmapRenderingContext();
+
+      break;
+  }
+  MOZ_ASSERT(ret);
+
+  ret->Initialize();
+  return ret.forget();
+}
+
+already_AddRefed<nsISupports> CanvasRenderingContextHelper::GetOrCreateContext(
+    JSContext* aCx, const nsAString& aContextId,
+    JS::Handle<JS::Value> aContextOptions, ErrorResult& aRv) {
+  CanvasContextType contextType;
+  if (!CanvasUtils::GetCanvasContextType(aContextId, &contextType))
+    return nullptr;
+
+  return GetOrCreateContext(aCx, contextType, aContextOptions, aRv);
+}
+
+already_AddRefed<nsISupports> CanvasRenderingContextHelper::GetOrCreateContext(
+    JSContext* aCx, CanvasContextType aContextType,
+    JS::Handle<JS::Value> aContextOptions, ErrorResult& aRv) {
+  if (!mCurrentContext) {
+    // This canvas doesn't have a context yet.
+    RefPtr<nsICanvasRenderingContextInternal> context;
+    context = CreateContext(aContextType);
+    if (!context) {
+      return nullptr;
+    }
+
+    // Ensure that the context participates in CC.  Note that returning a
+    // CC participant from QI doesn't addref.
+    nsXPCOMCycleCollectionParticipant* cp = nullptr;
+    CallQueryInterface(context, &cp);
+    if (!cp) {
+      aRv.Throw(NS_ERROR_FAILURE);
+      return nullptr;
+    }
+
+    mCurrentContext = std::move(context);
+    mCurrentContextType = aContextType;
+
+    // https://html.spec.whatwg.org/multipage/canvas.html#dom-canvas-getcontext-dev
+    // Step 1. If options is not an object, then set options to null.
+    JS::Rooted<JS::Value> options(RootingCx(), aContextOptions);
+    if (!options.isObject()) {
+      options.setNull();
+    }
+
+    nsresult rv = UpdateContext(aCx, options, aRv);
+    if (NS_FAILED(rv)) {
+      // See bug 645792 and bug 1215072.
+      // We want to throw only if dictionary initialization fails,
+      // so only in case aRv has been set to some error value.
+      if (aContextType == CanvasContextType::WebGL1) {
+        Telemetry::Accumulate(Telemetry::CANVAS_WEBGL_SUCCESS, 0);
+      } else if (aContextType == CanvasContextType::WebGL2) {
+        Telemetry::Accumulate(Telemetry::CANVAS_WEBGL2_SUCCESS, 0);
+      } else if (aContextType == CanvasContextType::WebGPU) {
+        // Telemetry::Accumulate(Telemetry::CANVAS_WEBGPU_SUCCESS, 0);
+      }
+      return nullptr;
+    }
+    if (aContextType == CanvasContextType::WebGL1) {
+      Telemetry::Accumulate(Telemetry::CANVAS_WEBGL_SUCCESS, 1);
+    } else if (aContextType == CanvasContextType::WebGL2) {
+      Telemetry::Accumulate(Telemetry::CANVAS_WEBGL2_SUCCESS, 1);
+    } else if (aContextType == CanvasContextType::WebGPU) {
+      // Telemetry::Accumulate(Telemetry::CANVAS_WEBGPU_SUCCESS, 1);
+    }
+  } else {
+    // We already have a context of some type.
+    if (aContextType != mCurrentContextType) return nullptr;
+  }
+
+  nsCOMPtr<nsICanvasRenderingContextInternal> context = mCurrentContext;
+  return context.forget();
+}
+
+nsresult CanvasRenderingContextHelper::UpdateContext(
+    JSContext* aCx, JS::Handle<JS::Value> aNewContextOptions,
+    ErrorResult& aRvForDictionaryInit) {
+  if (!mCurrentContext) return NS_OK;
+
+  nsIntSize sz = GetWidthHeight();
+
+  nsCOMPtr<nsICanvasRenderingContextInternal> currentContext = mCurrentContext;
+
+  currentContext->SetOpaqueValueFromOpaqueAttr(GetOpaqueAttr());
+
+  nsresult rv = currentContext->SetContextOptions(aCx, aNewContextOptions,
+                                                  aRvForDictionaryInit);
+  if (NS_FAILED(rv)) {
+    mCurrentContext = nullptr;
+    return rv;
+  }
+
+  rv = currentContext->SetDimensions(sz.width, sz.height);
+  if (NS_FAILED(rv)) {
+    mCurrentContext = nullptr;
+  }
+
+  return rv;
+}
+
+nsresult CanvasRenderingContextHelper::ParseParams(
+    JSContext* aCx, const nsAString& aType, const JS::Value& aEncoderOptions,
+    nsAString& outParams, bool* const outUsingCustomParseOptions) {
+  // Quality parameter is only valid for the image/jpeg and image/webp MIME
+  // types.
+  if (aType.EqualsLiteral("image/jpeg") || aType.EqualsLiteral("image/webp")) {
+    if (aEncoderOptions.isNumber()) {
+      double quality = aEncoderOptions.toNumber();
+      // Quality must be between 0.0 and 1.0, inclusive
+      if (quality >= 0.0 && quality <= 1.0) {
+        outParams.AppendLiteral("quality=");
+        outParams.AppendInt(NS_lround(quality * 100.0));
+      }
+    }
+  }
+
+  // If we haven't parsed the aParams check for proprietary options.
+  // The proprietary option -moz-parse-options will take a image lib encoder
+  // parse options string as is and pass it to the encoder.
+  *outUsingCustomParseOptions = false;
+  if (outParams.Length() == 0 && aEncoderOptions.isString()) {
+    constexpr auto mozParseOptions = u"-moz-parse-options:"_ns;
+    nsAutoJSString paramString;
+    if (!paramString.init(aCx, aEncoderOptions.toString())) {
+      return NS_ERROR_FAILURE;
+    }
+    if (StringBeginsWith(paramString, mozParseOptions)) {
+      nsDependentSubstring parseOptions =
+          Substring(paramString, mozParseOptions.Length(),
+                    paramString.Length() - mozParseOptions.Length());
+      outParams.Append(parseOptions);
+      *outUsingCustomParseOptions = true;
+    }
+  }
+
+  return NS_OK;
+}
+
+}  // namespace mozilla::dom