Extended error reporting for SVG attribute parsing

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

 /*
  * Copyright (C) Research In Motion Limited 2011. All rights reserved.
  * Copyright (C) 2011 Apple, Inc. All rights reserved.
  *
  * Redistribution and use in source and binary forms, with or without
  * modification, are permitted provided that the following conditions
  * are met:
  * 1. Redistributions of source code must retain the above copyright
  *    notice, this list of conditions and the following disclaimer.
  * 2. Redistributions in binary form must reproduce the above copyright
  *    notice, this list of conditions and the following disclaimer in the
  *    documentation and/or other materials provided with the distribution.
  *
  * THIS SOFTWARE IS PROVIDED BY APPLE INC. ``AS IS'' AND ANY
  * EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
  * PURPOSE ARE DISCLAIMED.  IN NO EVENT SHALL APPLE INC. OR
  * CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL,
  * EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO,
  * PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR
  * PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY
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  */
 
 #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