1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
|
// Copyright 2015 The Chromium Authors. All rights reserved.
// Copyright (C) 2016 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:
//
// * Redistributions of source code must retain the above copyright
// notice, this list of conditions and the following disclaimer.
// * 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.
// * Neither the name of Google Inc. nor the names of its
// contributors may be used to endorse or promote products derived from
// this software without specific prior written permission.
//
// THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
// "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 THE COPYRIGHT
// OWNER 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 OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
// (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
// OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
#include "config.h"
#include "CSSSupportsParser.h"
#include "CSSParserImpl.h"
namespace WebCore {
CSSSupportsParser::SupportsResult CSSSupportsParser::supportsCondition(CSSParserTokenRange range, CSSParserImpl& parser)
{
// FIXME: The spec allows leading whitespace in @supports but not CSS.supports,
// but major browser vendors allow it in CSS.supports also.
range.consumeWhitespace();
return CSSSupportsParser(parser).consumeCondition(range);
}
enum ClauseType { Unresolved, Conjunction, Disjunction };
CSSSupportsParser::SupportsResult CSSSupportsParser::consumeCondition(CSSParserTokenRange range)
{
if (range.peek().type() == IdentToken || range.peek().type() == FunctionToken)
return consumeNegation(range);
bool result;
ClauseType clauseType = Unresolved;
auto previousTokenType = IdentToken;
while (true) {
SupportsResult nextResult = consumeConditionInParenthesis(range, previousTokenType);
if (nextResult == Invalid)
return Invalid;
bool nextSupported = nextResult;
if (clauseType == Unresolved)
result = nextSupported;
else if (clauseType == Conjunction)
result &= nextSupported;
else
result |= nextSupported;
if (range.atEnd())
break;
range.consumeWhitespace();
if (range.atEnd())
break;
const CSSParserToken& token = range.peek();
if (token.type() != IdentToken && token.type() != FunctionToken)
return Invalid;
previousTokenType = token.type();
if (clauseType == Unresolved)
clauseType = token.value().length() == 3 ? Conjunction : Disjunction;
if ((clauseType == Conjunction && !equalIgnoringASCIICase(token.value(), "and"))
|| (clauseType == Disjunction && !equalIgnoringASCIICase(token.value(), "or")))
return Invalid;
if (token.type() == IdentToken)
range.consumeIncludingWhitespace();
}
return result ? Supported : Unsupported;
}
CSSSupportsParser::SupportsResult CSSSupportsParser::consumeNegation(CSSParserTokenRange range)
{
ASSERT(range.peek().type() == IdentToken || range.peek().type() == FunctionToken);
auto tokenType = range.peek().type();
if (!equalIgnoringASCIICase(range.peek().value(), "not"))
return Invalid;
if (range.peek().type() == IdentToken)
range.consumeIncludingWhitespace();
SupportsResult result = consumeConditionInParenthesis(range, tokenType);
range.consumeWhitespace();
if (!range.atEnd() || result == Invalid)
return Invalid;
return result ? Unsupported : Supported;
}
CSSSupportsParser::SupportsResult CSSSupportsParser::consumeConditionInParenthesis(CSSParserTokenRange& range, CSSParserTokenType startTokenType)
{
if (startTokenType == IdentToken && range.peek().type() != LeftParenthesisToken)
return Invalid;
CSSParserTokenRange innerRange = range.consumeBlock();
innerRange.consumeWhitespace();
SupportsResult result = consumeCondition(innerRange);
if (result != Invalid)
return result;
if (innerRange.peek().type() == FunctionToken) {
innerRange.consumeComponentValue();
return Unsupported;
}
return innerRange.peek().type() == IdentToken && m_parser.supportsDeclaration(innerRange) ? Supported : Unsupported;
}
} // namespace WebCore
|
