dom/canvas/CanvasUtils.h

   1 /* -*- Mode: C++; tab-width: 20; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
   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 #ifndef _CANVASUTILS_H_
   7 #define _CANVASUTILS_H_
   8
   9 #include "CanvasRenderingContextHelper.h"
  10 #include "mozilla/CheckedInt.h"
  11 #include "mozilla/dom/ToJSValue.h"
  12 #include "jsapi.h"
  13 #include "js/Array.h"  // JS::GetArrayLength
  14 #include "mozilla/FloatingPoint.h"
  15
  16 class nsIPrincipal;
  17
  18 namespace mozilla {
  19
  20 namespace dom {
  21 class Document;
  22 class HTMLCanvasElement;
  23 }  // namespace dom
  24
  25 namespace CanvasUtils {
  26
  27 bool GetCanvasContextType(const nsAString& str,
  28                           dom::CanvasContextType* const out_type);
  29
  30 // Check that the rectangle [x,y,w,h] is a subrectangle of
  31 // [0,0,realWidth,realHeight]
  32
  33 inline bool CheckSaneSubrectSize(int32_t x, int32_t y, int32_t w, int32_t h,
  34                                  int32_t realWidth, int32_t realHeight) {
  35   CheckedInt32 checked_xmost = CheckedInt32(x) + w;
  36   CheckedInt32 checked_ymost = CheckedInt32(y) + h;
  37
  38   return w >= 0 && h >= 0 && x >= 0 && y >= 0 && checked_xmost.isValid() &&
  39          checked_xmost.value() <= realWidth && checked_ymost.isValid() &&
  40          checked_ymost.value() <= realHeight;
  41 }
  42
  43 // Flag aCanvasElement as write-only if drawing an image with aPrincipal
  44 // onto it would make it such.
  45
  46 void DoDrawImageSecurityCheck(dom::HTMLCanvasElement* aCanvasElement,
  47                               nsIPrincipal* aPrincipal, bool forceWriteOnly,
  48                               bool CORSUsed);
  49
  50 // Check if the context is chrome or has the permission to drawWindow
  51 bool HasDrawWindowPrivilege(JSContext* aCx, JSObject* aObj);
  52
  53 // Check site-specific permission and display prompt if appropriate.
  54 bool IsImageExtractionAllowed(dom::Document* aDocument, JSContext* aCx,
  55                               nsIPrincipal& aPrincipal);
  56
  57 // Make a double out of |v|, treating undefined values as 0.0 (for
  58 // the sake of sparse arrays).  Return true iff coercion
  59 // succeeded.
  60 bool CoerceDouble(const JS::Value& v, double* d);
  61
  62 /* Float validation stuff */
  63 #define VALIDATE(_f) \
  64   if (!IsFinite(_f)) return false
  65
  66 inline bool FloatValidate(double f1) {
  67   VALIDATE(f1);
  68   return true;
  69 }
  70
  71 inline bool FloatValidate(double f1, double f2) {
  72   VALIDATE(f1);
  73   VALIDATE(f2);
  74   return true;
  75 }
  76
  77 inline bool FloatValidate(double f1, double f2, double f3) {
  78   VALIDATE(f1);
  79   VALIDATE(f2);
  80   VALIDATE(f3);
  81   return true;
  82 }
  83
  84 inline bool FloatValidate(double f1, double f2, double f3, double f4) {
  85   VALIDATE(f1);
  86   VALIDATE(f2);
  87   VALIDATE(f3);
  88   VALIDATE(f4);
  89   return true;
  90 }
  91
  92 inline bool FloatValidate(double f1, double f2, double f3, double f4,
  93                           double f5) {
  94   VALIDATE(f1);
  95   VALIDATE(f2);
  96   VALIDATE(f3);
  97   VALIDATE(f4);
  98   VALIDATE(f5);
  99   return true;
 100 }
 101
 102 inline bool FloatValidate(double f1, double f2, double f3, double f4, double f5,
 103                           double f6) {
 104   VALIDATE(f1);
 105   VALIDATE(f2);
 106   VALIDATE(f3);
 107   VALIDATE(f4);
 108   VALIDATE(f5);
 109   VALIDATE(f6);
 110   return true;
 111 }
 112
 113 #undef VALIDATE
 114
 115 template <typename T>
 116 nsresult JSValToDashArray(JSContext* cx, const JS::Value& patternArray,
 117                           nsTArray<T>& dashes) {
 118   // The cap is pretty arbitrary.  16k should be enough for
 119   // anybody...
 120   static const uint32_t MAX_NUM_DASHES = 1 << 14;
 121
 122   if (!patternArray.isPrimitive()) {
 123     JS::Rooted<JSObject*> obj(cx, patternArray.toObjectOrNull());
 124     uint32_t length;
 125     if (!JS::GetArrayLength(cx, obj, &length)) {
 126       // Not an array-like thing
 127       return NS_ERROR_INVALID_ARG;
 128     } else if (length > MAX_NUM_DASHES) {
 129       // Too many dashes in the pattern
 130       return NS_ERROR_ILLEGAL_VALUE;
 131     }
 132
 133     bool haveNonzeroElement = false;
 134     for (uint32_t i = 0; i < length; ++i) {
 135       JS::Rooted<JS::Value> elt(cx);
 136       double d;
 137       if (!JS_GetElement(cx, obj, i, &elt)) {
 138         return NS_ERROR_FAILURE;
 139       }
 140       if (!(CoerceDouble(elt, &d) && FloatValidate(d) && d >= 0.0)) {
 141         // Pattern elements must be finite "numbers" >= 0.
 142         return NS_ERROR_INVALID_ARG;
 143       } else if (d > 0.0) {
 144         haveNonzeroElement = true;
 145       }
 146       if (!dashes.AppendElement(d, mozilla::fallible)) {
 147         return NS_ERROR_OUT_OF_MEMORY;
 148       }
 149     }
 150
 151     if (dashes.Length() > 0 && !haveNonzeroElement) {
 152       // An all-zero pattern makes no sense.
 153       return NS_ERROR_ILLEGAL_VALUE;
 154     }
 155   } else if (!(patternArray.isUndefined() || patternArray.isNull())) {
 156     // undefined and null mean "reset to no dash".  Any other
 157     // random garbage is a type error.
 158     return NS_ERROR_INVALID_ARG;
 159   }
 160
 161   return NS_OK;
 162 }
 163
 164 template <typename T>
 165 void DashArrayToJSVal(nsTArray<T>& dashes, JSContext* cx,
 166                       JS::MutableHandle<JS::Value> retval,
 167                       mozilla::ErrorResult& rv) {
 168   if (dashes.IsEmpty()) {
 169     retval.setNull();
 170     return;
 171   }
 172   JS::Rooted<JS::Value> val(cx);
 173   if (!mozilla::dom::ToJSValue(cx, dashes, retval)) {
 174     rv.Throw(NS_ERROR_OUT_OF_MEMORY);
 175   }
 176 }
 177
 178 // returns true if write-only mode must used for this principal based on
 179 // the incumbent global.
 180 bool CheckWriteOnlySecurity(bool aCORSUsed, nsIPrincipal* aPrincipal,
 181                             bool aHadCrossOriginRedirects);
 182
 183 }  // namespace CanvasUtils
 184 }  // namespace mozilla
 185
 186 #endif /* _CANVASUTILS_H_ */