Removing duplicate functions and symbol names in core/css

third_party/WebKit/Source/core/css/CSSPrimitiveValue.h

 /*
  * (C) 1999-2003 Lars Knoll (knoll@kde.org)
  * Copyright (C) 2004, 2005, 2006, 2008 Apple Inc. All rights reserved.
  * Copyright (C) 2007 Alexey Proskuryakov <ap@webkit.org>
  *
  * This library is free software; you can redistribute it and/or
  * modify it under the terms of the GNU Library General Public
  * License as published by the Free Software Foundation; either
  * version 2 of the License, or (at your option) any later version.
  *
@@ skipping 303 matching lines @@
     // FIXME: oilpan: Should be a member, but no support for members in unions.
     // Just trace the raw ptr for now.
     CSSCalcValue* calc;
   } m_value;
 };
 
 using CSSLengthArray = CSSPrimitiveValue::CSSLengthArray;
 
 DEFINE_CSS_VALUE_TYPE_CASTS(CSSPrimitiveValue, isPrimitiveValue());
 
+template <>
+int CSSPrimitiveValue::computeLength(const CSSToLengthConversionData&) const;
+
+template <>
+Length CSSPrimitiveValue::computeLength(const CSSToLengthConversionData&) const;
+
+template <>
+unsigned CSSPrimitiveValue::computeLength(
+    const CSSToLengthConversionData&) const;
+
+template <>
+short CSSPrimitiveValue::computeLength(const CSSToLengthConversionData&) const;
+
+template <>
+float CSSPrimitiveValue::computeLength(const CSSToLengthConversionData&) const;
+
+template <>
+double CSSPrimitiveValue::computeLength(const CSSToLengthConversionData&) const;

[rune, 2017/04/05 10:54:39]

Can you explain why these are necessary?

[Daniel Bratell, 2017/04/05 12:05:39]

The computeLength functions have explicit specializations in
CSSPrimitiveValue.cpp which are used, but only if the calling code knows about
them. In CSSGradientValue.cpp these functions were called and got automatic
instantiations which then collided with the explicit instantiations in the
compiler. I think the linker would have made them the same anyway, but it
doesn't work if it's in the same compilation unit.

The exact error message is:
In file included from gen/blink/core/css_jumbo.cpp:53:
gen/blink/core/../../../../../third_party/WebKit/Source/core/css/CSSPrimitiveValue.cpp:310:26:
error: explicit specialization of 'computeLength<float>' after instantiation
float CSSPrimitiveValue::computeLength(
                         ^
gen/blink/core/../../../../../third_party/WebKit/Source/core/css/CSSGradientValue.cpp:495:35:
note: implicit instantiation first required here
          length = stop.m_offset->computeLength<float>(conversionData);
                                  ^
In file included from gen/blink/core/css_jumbo.cpp:53:
gen/blink/core/../../../../../third_party/WebKit/Source/core/css/CSSPrimitiveValue.cpp:316:27:
error: explicit specialization of 'computeLength<double>' after instantiation
double CSSPrimitiveValue::computeLength(
                          ^
gen/blink/core/../../../../../third_party/WebKit/Source/core/css/CSSCalculationValue.cpp:190:22:
note: implicit instantiation first required here
            m_value->computeLength<double>(conversionData) * multiplier);
                     ^

[rune, 2017/04/05 19:40:22]

I don't know enough about templates and compilers to say if there's a better
way, and without a comment why they're here someone might just remove these
declarations later on. The rest looks good. If you remove these changes, I can
approve.

 }  // namespace blink
 
 #endif  // CSSPrimitiveValue_h