dom/canvas/CanvasUtils.cpp

   1 /* -*- Mode: C++; tab-width: 20; indent-tabs-mode: nil; c-basic-offset: 4 -*- */
   2 /* This Source Code Form is subject to the terms of the Mozilla Public
   3  * License, v. 2.0. If a copy of the MPL was not distributed with this
   4  * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
   5
   6 #include <stdlib.h>
   7 #include <stdarg.h>
   8
   9 #include "prprf.h"
  10
  11 #include "nsIServiceManager.h"
  12
  13 #include "nsIConsoleService.h"
  14 #include "nsIDOMCanvasRenderingContext2D.h"
  15 #include "nsICanvasRenderingContextInternal.h"
  16 #include "nsIHTMLCollection.h"
  17 #include "mozilla/dom/HTMLCanvasElement.h"
  18 #include "nsIPrincipal.h"
  19
  20 #include "nsGfxCIID.h"
  21
  22 #include "nsTArray.h"
  23
  24 #include "CanvasUtils.h"
  25 #include "mozilla/gfx/Matrix.h"
  26
  27 using namespace mozilla::gfx;
  28
  29 namespace mozilla {
  30 namespace CanvasUtils {
  31
  32 void
  33 DoDrawImageSecurityCheck(dom::HTMLCanvasElement *aCanvasElement,
  34                          nsIPrincipal *aPrincipal,
  35                          bool forceWriteOnly,
  36                          bool CORSUsed)
  37 {
  38     NS_PRECONDITION(aPrincipal, "Must have a principal here");
  39
  40     // Callers should ensure that mCanvasElement is non-null before calling this
  41     if (!aCanvasElement) {
  42         NS_WARNING("DoDrawImageSecurityCheck called without canvas element!");
  43         return;
  44     }
  45
  46     if (aCanvasElement->IsWriteOnly())
  47         return;
  48
  49     // If we explicitly set WriteOnly just do it and get out
  50     if (forceWriteOnly) {
  51         aCanvasElement->SetWriteOnly();
  52         return;
  53     }
  54
  55     // No need to do a security check if the image used CORS for the load
  56     if (CORSUsed)
  57         return;
  58
  59     if (aCanvasElement->NodePrincipal()->Subsumes(aPrincipal)) {
  60         // This canvas has access to that image anyway
  61         return;
  62     }
  63
  64     aCanvasElement->SetWriteOnly();
  65 }
  66
  67 bool
  68 CoerceDouble(JS::Value v, double* d)
  69 {
  70     if (v.isDouble()) {
  71         *d = v.toDouble();
  72     } else if (v.isInt32()) {
  73         *d = double(v.toInt32());
  74     } else if (v.isUndefined()) {
  75         *d = 0.0;
  76     } else {
  77         return false;
  78     }
  79     return true;
  80 }
  81
  82 } // namespace CanvasUtils
  83 } // namespace mozilla