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
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
|
/*
* Copyright (C) 2010 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. AND ITS 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 APPLE INC. OR ITS 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 "VisitedLinkProvider.h"
#include "SharedMemory.h"
#include "VisitedLinkTable.h"
#include "WebContext.h"
#include "WebProcessMessages.h"
using namespace WebCore;
namespace WebKit {
static const int VisitedLinkTableMaxLoad = 2;
VisitedLinkProvider::VisitedLinkProvider(WebContext* context)
: m_context(context)
, m_visitedLinksPopulated(false)
, m_keyCount(0)
, m_tableSize(0)
, m_pendingVisitedLinksTimer(RunLoop::main(), this, &VisitedLinkProvider::pendingVisitedLinksTimerFired)
{
}
void VisitedLinkProvider::processDidFinishLaunching(WebProcessProxy* process)
{
m_processesWithoutVisitedLinkState.add(process);
if (m_keyCount)
m_pendingVisitedLinksTimer.startOneShot(0);
if (m_visitedLinksPopulated)
return;
m_context->populateVisitedLinks();
m_visitedLinksPopulated = true;
}
void VisitedLinkProvider::addVisitedLink(LinkHash linkHash)
{
m_pendingVisitedLinks.add(linkHash);
if (!m_pendingVisitedLinksTimer.isActive())
m_pendingVisitedLinksTimer.startOneShot(0);
}
void VisitedLinkProvider::processDidClose(WebProcessProxy* process)
{
m_processesWithVisitedLinkState.remove(process);
m_processesWithoutVisitedLinkState.remove(process);
}
static unsigned nextPowerOf2(unsigned v)
{
// Taken from http://www.cs.utk.edu/~vose/c-stuff/bithacks.html
// Devised by Sean Anderson, Sepember 14, 2001
v--;
v |= v >> 1;
v |= v >> 2;
v |= v >> 4;
v |= v >> 8;
v |= v >> 16;
v++;
return v;
}
static unsigned tableSizeForKeyCount(unsigned keyCount)
{
// We want the table to be at least half empty.
unsigned tableSize = nextPowerOf2(keyCount * VisitedLinkTableMaxLoad);
// Ensure that the table size is at least the size of a page.
size_t minimumTableSize = SharedMemory::systemPageSize() / sizeof(LinkHash);
if (tableSize < minimumTableSize)
return minimumTableSize;
return tableSize;
}
void VisitedLinkProvider::pendingVisitedLinksTimerFired()
{
Vector<WebCore::LinkHash> pendingVisitedLinks;
copyToVector(m_pendingVisitedLinks, pendingVisitedLinks);
m_pendingVisitedLinks.clear();
unsigned currentTableSize = m_tableSize;
// Upper bound on needed size - some of the links may be duplicates, in which case we could have done with less.
unsigned newTableSize = tableSizeForKeyCount(m_keyCount + pendingVisitedLinks.size());
// Never decrease table size when adding to it, to avoid unneeded churn.
newTableSize = std::max(currentTableSize, newTableSize);
// Links that were added.
Vector<WebCore::LinkHash> addedVisitedLinks;
// VisitedLinkTable remains internally consistent when adding, so it's OK to modify it in place
// even if a web process is accessing it at the same time.
if (currentTableSize != newTableSize) {
RefPtr<SharedMemory> newTableMemory = SharedMemory::create(newTableSize * sizeof(LinkHash));
// We failed to create the shared memory.
if (!newTableMemory) {
LOG_ERROR("Could not allocate shared memory for visited link table");
return;
}
memset(newTableMemory->data(), 0, newTableMemory->size());
RefPtr<SharedMemory> currentTableMemory = m_table.sharedMemory();
m_table.setSharedMemory(newTableMemory);
m_tableSize = newTableSize;
if (currentTableMemory) {
ASSERT(currentTableMemory->size() == currentTableSize * sizeof(LinkHash));
// Go through the current hash table and re-add all entries to the new hash table.
const LinkHash* currentLinkHashes = static_cast<const LinkHash*>(currentTableMemory->data());
for (unsigned i = 0; i < currentTableSize; ++i) {
LinkHash linkHash = currentLinkHashes[i];
if (!linkHash)
continue;
// It should always be possible to add the link hash to a new table.
if (!m_table.addLinkHash(linkHash))
ASSERT_NOT_REACHED();
}
}
}
for (size_t i = 0; i < pendingVisitedLinks.size(); ++i) {
if (m_table.addLinkHash(pendingVisitedLinks[i]))
addedVisitedLinks.append(pendingVisitedLinks[i]);
}
m_keyCount += pendingVisitedLinks.size();
for (HashSet<WebProcessProxy*>::iterator iter = m_processesWithVisitedLinkState.begin(); iter != m_processesWithVisitedLinkState.end(); ++iter) {
WebProcessProxy* process = *iter;
if (currentTableSize != newTableSize) {
// In the rare case of needing to resize the table, we'll bypass the VisitedLinkStateChanged optimization,
// and unconditionally use AllVisitedLinkStateChanged for the process.
m_processesWithoutVisitedLinkState.add(process);
continue;
}
if (addedVisitedLinks.size() <= 20)
process->send(Messages::WebProcess::VisitedLinkStateChanged(addedVisitedLinks), 0);
else
process->send(Messages::WebProcess::AllVisitedLinkStateChanged(), 0);
}
for (HashSet<WebProcessProxy*>::iterator iter = m_processesWithoutVisitedLinkState.begin(); iter != m_processesWithoutVisitedLinkState.end(); ++iter) {
WebProcessProxy* process = *iter;
SharedMemory::Handle handle;
if (!m_table.sharedMemory()->createHandle(handle, SharedMemory::ReadOnly))
return;
process->send(Messages::WebProcess::SetVisitedLinkTable(handle), 0);
process->send(Messages::WebProcess::AllVisitedLinkStateChanged(), 0);
m_processesWithVisitedLinkState.add(process);
}
m_processesWithoutVisitedLinkState.clear();
}
} // namespace WebKit
|
