1 files changed, 130 insertions, 0 deletions
diff --git a/dom/canvas/CanvasUtils.cpp b/dom/canvas/CanvasUtils.cpp
new file mode 100644
index 000000000..c7cfed83f
--- /dev/null
+++ b/dom/canvas/CanvasUtils.cpp
@@ -0,0 +1,130 @@
+/* -*- Mode: C++; tab-width: 20; indent-tabs-mode: nil; c-basic-offset: 4 -*- */
+/* 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 <stdlib.h>
+#include <stdarg.h>
+
+#include "prprf.h"
+
+#include "nsIServiceManager.h"
+
+#include "nsIConsoleService.h"
+#include "nsIDOMCanvasRenderingContext2D.h"
+#include "nsICanvasRenderingContextInternal.h"
+#include "nsIHTMLCollection.h"
+#include "mozilla/dom/HTMLCanvasElement.h"
+#include "nsIPrincipal.h"
+
+#include "nsGfxCIID.h"
+
+#include "nsTArray.h"
+
+#include "CanvasUtils.h"
+#include "mozilla/gfx/Matrix.h"
+#include "WebGL2Context.h"
+
+using namespace mozilla::gfx;
+
+namespace mozilla {
+namespace CanvasUtils {
+
+bool
+GetCanvasContextType(const nsAString& str, dom::CanvasContextType* const out_type)
+{
+  if (str.EqualsLiteral("2d")) {
+    *out_type = dom::CanvasContextType::Canvas2D;
+    return true;
+  }
+
+  if (str.EqualsLiteral("experimental-webgl")) {
+    *out_type = dom::CanvasContextType::WebGL1;
+    return true;
+  }
+
+#ifdef MOZ_WEBGL_CONFORMANT
+  if (str.EqualsLiteral("webgl")) {
+    /* WebGL 1.0, $2.1 "Context Creation":
+     *   If the user agent supports both the webgl and experimental-webgl
+     *   canvas context types, they shall be treated as aliases.
+     */
+    *out_type = dom::CanvasContextType::WebGL1;
+    return true;
+  }
+#endif
+
+  if (WebGL2Context::IsSupported()) {
+    if (str.EqualsLiteral("webgl2")) {
+      *out_type = dom::CanvasContextType::WebGL2;
+      return true;
+    }
+  }
+
+  if (str.EqualsLiteral("bitmaprenderer")) {
+    *out_type = dom::CanvasContextType::ImageBitmap;
+    return true;
+  }
+
+  return false;
+}
+
+/**
+ * This security check utility might be called from an source that never taints
+ * others. For example, while painting a CanvasPattern, which is created from an
+ * ImageBitmap, onto a canvas. In this case, the caller could set the CORSUsed
+ * true in order to pass this check and leave the aPrincipal to be a nullptr
+ * since the aPrincipal is not going to be used.
+ */
+void
+DoDrawImageSecurityCheck(dom::HTMLCanvasElement *aCanvasElement,
+                         nsIPrincipal *aPrincipal,
+                         bool forceWriteOnly,
+                         bool CORSUsed)
+{
+    // Callers should ensure that mCanvasElement is non-null before calling this
+    if (!aCanvasElement) {
+        NS_WARNING("DoDrawImageSecurityCheck called without canvas element!");
+        return;
+    }
+
+    if (aCanvasElement->IsWriteOnly())
+        return;
+
+    // If we explicitly set WriteOnly just do it and get out
+    if (forceWriteOnly) {
+        aCanvasElement->SetWriteOnly();
+        return;
+    }
+
+    // No need to do a security check if the image used CORS for the load
+    if (CORSUsed)
+        return;
+
+    NS_PRECONDITION(aPrincipal, "Must have a principal here");
+
+    if (aCanvasElement->NodePrincipal()->Subsumes(aPrincipal)) {
+        // This canvas has access to that image anyway
+        return;
+    }
+
+    aCanvasElement->SetWriteOnly();
+}
+
+bool
+CoerceDouble(const JS::Value& v, double* d)
+{
+    if (v.isDouble()) {
+        *d = v.toDouble();
+    } else if (v.isInt32()) {
+        *d = double(v.toInt32());
+    } else if (v.isUndefined()) {
+        *d = 0.0;
+    } else {
+        return false;
+    }
+    return true;
+}
+
+} // namespace CanvasUtils
+} // namespace mozilla