Extended error reporting for SVG attribute parsing

third_party/WebKit/Source/core/svg/SVGParsingError.h

Index: third_party/WebKit/Source/core/svg/SVGParsingError.h
diff --git a/third_party/WebKit/Source/core/svg/SVGParsingError.h b/third_party/WebKit/Source/core/svg/SVGParsingError.h
index 5a40f9f4c101fe0bb403d1eaf80b9d6030b319c8..a5531319306ead64bc2d86f2a1cb12af6a673bd9 100644
--- a/third_party/WebKit/Source/core/svg/SVGParsingError.h
+++ b/third_party/WebKit/Source/core/svg/SVGParsingError.h
@@ -27,14 +27,71 @@
 #ifndef SVGParsingError_h
 #define SVGParsingError_h
 
+#include "wtf/MathExtras.h"
+#include "wtf/text/WTFString.h"
+
 namespace blink {
 
-enum SVGParsingError {
+class QualifiedName;
+
+enum class SVGParseStatus {
     NoError,
-    ParsingAttributeFailedError,
-    NegativeValueForbiddenError
+
+    // Syntax errors
+    TrailingGarbage,
+    ExpectedBoolean,
+    ExpectedEnumeration,
+
+    // Semantic errors
+    NegativeValue,
+
+    // Generic error
+    ParsingFailed,
+};
+
+class SVGParsingError {
+    STACK_ALLOCATED();
+public:
+    SVGParsingError(SVGParseStatus status = SVGParseStatus::NoError, size_t locus = 0)
+        : m_status(static_cast<unsigned>(status))
+        , m_locus(checkLocus(locus))
+    {
+        ASSERT(this->status() == status);
+    }
+
+    SVGParseStatus status() const { return static_cast<SVGParseStatus>(m_status); }
+
+    bool hasLocus() const { return m_locus != kNoLocus; }
+    unsigned locus() const { return m_locus; }
+
+    // Generates a string describing this error for |value| in the context of
+    // an <element, attribute>-name pair.
+    String format(const String& tagName, const QualifiedName&, const AtomicString& value) const;
+
+private:
+    static const int kLocusBits = 24;
+    static const unsigned kNoLocus = (1u << kLocusBits) - 1;
+
+    static unsigned checkLocus(size_t locus)
+    {
+        // Clamp to fit in the number of bits available. If the character index
+        // encoded by the locus does not fit in the number of bits allocated
+        // for it, the locus will be disabled (set to kNoLocus). This means
+        // that very long values will be output in their entirety. That should
+        // however be rather uncommon.
+        return clampTo<unsigned>(locus, 0, kNoLocus);
+    }
+
+    unsigned m_status : 8;
+    unsigned m_locus : kLocusBits; // The locus (character index) of the error within the parsed string.
 };
 
+inline bool operator==(const SVGParsingError& error, SVGParseStatus status)
+{
+    return error.status() == status;
+}
+inline bool operator!=(const SVGParsingError& error, SVGParseStatus status) { return !(error == status); }
+
 } // namespace blink
 
 #endif // SVGParsingError_h