Initial error handling code

src/core/SkValidationUtils.h

Index: src/core/SkValidationUtils.h
diff --git a/src/core/SkValidationUtils.h b/src/core/SkValidationUtils.h
new file mode 100644
index 0000000000000000000000000000000000000000..e4bb83332159f18be17ea2422ecd91fa87f35c45
--- /dev/null
+++ b/src/core/SkValidationUtils.h
@@ -0,0 +1,58 @@
+/*
+ * Copyright 2013 Google Inc.
+ *
+ * Use of this source code is governed by a BSD-style license that can be
+ * found in the LICENSE file.
+ */
+
+#ifndef SkValidationUtils_DEFINED
+#define SkValidationUtils_DEFINED
+
+#include "SkBitmap.h"
+#include "SkXfermode.h"
+
+/** Returns true if coeff's value is in the SkXfermode::Coeff enum.
+  */
+static inline bool SkIsValidCoeff(SkXfermode::Coeff coeff) {
+    return coeff >= 0 && coeff < SkXfermode::kCoeffCount;
+}
+
+/** Returns true if mode's value is in the SkXfermode::Mode enum.
+  */
+static inline bool SkIsValidMode(SkXfermode::Mode mode) {
+    return (mode >= 0) && (mode <= SkXfermode::kLastMode);
+}
+
+/** Returns true if config's value is in the SkBitmap::Config enum.
+  */
+static inline bool SkIsValidConfig(SkBitmap::Config config) {
+    return (config >= 0) && (config <= SkBitmap::kLastConfig);
+}
+
+/** Returns true if the rect's dimensions are between 0 and SK_MaxS32
+  */
+static inline bool SkIsValidRect(const SkIRect& rect) {
+    return !rect.isInverted() &&
+           // Make sure width() and height() are also valid
+           ((rect.fLeft >= 0) || (rect.fRight <= 0) ||

[reed1, 2013/09/04 20:37:41]

Is this section the same as

rect.width() >= 0 && rect.height() >= 0

?

+            ((rect.fRight - SK_MaxS32) <= rect.fLeft)) &&
+           ((rect.fTop >= 0) || (rect.fBottom <= 0) ||
+            ((rect.fBottom - SK_MaxS32) <= rect.fTop));
+}
+
+/** Returns true if the rect's dimensions are between 0 and SK_ScalarMax
+  */
+static inline bool SkIsValidRect(const SkRect& rect) {
+    return SkScalarIsFinite(rect.fLeft) &&

[reed1, 2013/09/04 20:37:41]

Is all of this the same as

return !rect.inverted() && SkScalarIsFinite(rect.width()) &&
SkScalarIsFinite(rect.height());

?

+           SkScalarIsFinite(rect.fTop) &&
+           SkScalarIsFinite(rect.fRight) &&
+           SkScalarIsFinite(rect.fBottom) &&
+           !rect.isInverted() &&
+           // Make sure width() and height() are also valid
+           ((rect.fLeft >= 0) || (rect.fRight <= 0) ||
+            ((rect.fRight - SK_ScalarMax) <= rect.fLeft)) &&
+           ((rect.fTop >= 0) || (rect.fBottom <= 0) ||
+            ((rect.fBottom - SK_ScalarMax) <= rect.fTop));
+}
+
+#endif