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
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
|
/*
* Copyright (C) 2013 Google, 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 GOOGLE 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 GOOGLE 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
* 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"
#if ENABLE(THREADED_HTML_PARSER)
#include "HTMLIdentifier.h"
#include "HTMLNames.h"
#include <wtf/HashMap.h>
#include <wtf/MainThread.h>
#include <wtf/text/StringHash.h>
namespace WebCore {
using namespace HTMLNames;
typedef std::pair<unsigned, StringImpl*> IdentifierEntry;
typedef HashMap<unsigned, IdentifierEntry, AlreadyHashed> IdentifierTable;
unsigned HTMLIdentifier::maxNameLength = 0;
static IdentifierTable& identifierTable()
{
DEFINE_STATIC_LOCAL(IdentifierTable, table, ());
ASSERT(isMainThread() || !table.isEmpty());
return table;
}
#ifndef NDEBUG
bool HTMLIdentifier::hasIndex(const StringImpl* string)
{
const IdentifierTable& table = identifierTable();
return table.contains(string->hash());
}
#endif
unsigned HTMLIdentifier::findIndex(const UChar* characters, unsigned length)
{
// We don't need to try hashing if we know the string is too long.
if (length > maxNameLength)
return invalidIndex;
// computeHashAndMaskTop8Bits is the function StringImpl::hash() uses.
unsigned hash = StringHasher::computeHashAndMaskTop8Bits(characters, length);
const IdentifierTable& table = identifierTable();
ASSERT(!table.isEmpty());
IdentifierTable::const_iterator it = table.find(hash);
if (it == table.end())
return invalidIndex;
// It's possible to have hash collisions between arbitrary strings and
// known identifiers (e.g. "bvvfg" collides with "script").
// However ASSERTs in addNames() guard against there ever being collisions
// between known identifiers.
if (!equal(it->value.second, characters, length))
return invalidIndex;
return it->value.first;
}
const unsigned kHTMLNamesIndexOffset = 0;
const unsigned kHTMLAttrsIndexOffset = 1000;
COMPILE_ASSERT(kHTMLAttrsIndexOffset > HTMLTagsCount, kHTMLAttrsIndexOffset_should_be_larger_than_HTMLTagsCount);
static const String& nameForIndex(unsigned index)
{
unsigned adjustedIndex;
QualifiedName** names;
if (index < kHTMLAttrsIndexOffset) {
ASSERT(index < kHTMLNamesIndexOffset + HTMLTagsCount);
adjustedIndex = index - kHTMLNamesIndexOffset;
names = getHTMLTags();
} else {
ASSERT(index < kHTMLAttrsIndexOffset + HTMLAttrsCount);
adjustedIndex = index - kHTMLAttrsIndexOffset;
names = getHTMLAttrs();
}
// HTMLAttrs and HTMLNames may have collisions, but
// we shouldn't care which we ended up storing, since their
// components are all AtomicStrings and should use the same
// underlying StringImpl*.
return names[adjustedIndex]->localName().string();
}
const String& HTMLIdentifier::asString() const
{
ASSERT(isMainThread());
if (m_index != invalidIndex)
return nameForIndex(m_index);
return m_string;
}
const StringImpl* HTMLIdentifier::asStringImpl() const
{
if (m_index != invalidIndex)
return nameForIndex(m_index).impl();
return m_string.impl();
}
void HTMLIdentifier::addNames(QualifiedName** names, unsigned namesCount, unsigned indexOffset)
{
IdentifierTable& table = identifierTable();
for (unsigned i = 0; i < namesCount; ++i) {
StringImpl* name = names[i]->localName().impl();
unsigned hash = name->hash();
unsigned index = i + indexOffset;
IdentifierEntry entry(index, name);
IdentifierTable::AddResult addResult = table.add(hash, entry);
maxNameLength = std::max(maxNameLength, name->length());
// Ensure we're using the same hashing algorithm to get and set.
ASSERT_UNUSED(addResult, !addResult.isNewEntry || HTMLIdentifier::findIndex(name->characters(), name->length()) == index);
// We expect some hash collisions, but only for identical strings.
// Since all of these names are AtomicStrings pointers should be equal.
// Note: If you hit this ASSERT, then we had a hash collision among
// HTMLNames strings, and we need to re-design how we use this hash!
ASSERT_UNUSED(addResult, !addResult.isNewEntry || name == addResult.iterator->value.second);
}
}
void HTMLIdentifier::init()
{
ASSERT(isMainThread()); // Not technically necessary, but this is our current expected usage.
static bool isInitialized = false;
if (isInitialized)
return;
isInitialized = true;
// FIXME: We should atomize small whitespace (\n, \n\n, etc.)
addNames(getHTMLTags(), HTMLTagsCount, kHTMLNamesIndexOffset);
addNames(getHTMLAttrs(), HTMLAttrsCount, kHTMLAttrsIndexOffset);
}
}
#endif // ENABLE(THREADED_HTML_PARSER)
|
