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) 2012 The Chromium Authors. All rights reserved.
// Use of this source code is governed by a BSD-style license that can be
// found in the LICENSE file.
#include "content/common/font_cache_dispatcher_win.h"
#include <map>
#include <vector>
#include "base/logging.h"
#include "base/profiler/scoped_tracker.h"
#include "base/strings/string16.h"
#include "content/common/child_process_messages.h"
namespace content {
namespace {
typedef std::vector<base::string16> FontNameVector;
typedef std::map<FontCacheDispatcher*, FontNameVector> DispatcherToFontNames;
class FontCache {
public:
static FontCache* GetInstance() {
return Singleton<FontCache>::get();
}
void PreCacheFont(const LOGFONT& font, FontCacheDispatcher* dispatcher) {
// TODO(ananta): Remove ScopedTracker below once crbug.com/90127 is fixed.
tracked_objects::ScopedTracker tracking_profile(
FROM_HERE_WITH_EXPLICIT_FUNCTION("90127 FontCache::PreCacheFont"));
typedef std::map<base::string16, FontCache::CacheElement> FontNameToElement;
base::AutoLock lock(mutex_);
// Fetch the font into memory.
// No matter the font is cached or not, we load it to avoid GDI swapping out
// that font file.
HDC hdc = GetDC(NULL);
HFONT font_handle = CreateFontIndirect(&font);
DCHECK(NULL != font_handle);
HGDIOBJ old_font = SelectObject(hdc, font_handle);
DCHECK(NULL != old_font);
TEXTMETRIC tm;
BOOL ret = GetTextMetrics(hdc, &tm);
DCHECK(ret);
base::string16 font_name = font.lfFaceName;
int ref_count_inc = 1;
FontNameVector::iterator it =
std::find(dispatcher_font_map_[dispatcher].begin(),
dispatcher_font_map_[dispatcher].end(),
font_name);
if (it == dispatcher_font_map_[dispatcher].end()) {
// Requested font is new to cache.
dispatcher_font_map_[dispatcher].push_back(font_name);
} else {
ref_count_inc = 0;
}
if (cache_[font_name].ref_count_ == 0) { // Requested font is new to cache.
cache_[font_name].ref_count_ = 1;
} else { // Requested font is already in cache, release old handles.
SelectObject(cache_[font_name].dc_, cache_[font_name].old_font_);
DeleteObject(cache_[font_name].font_);
ReleaseDC(NULL, cache_[font_name].dc_);
}
cache_[font_name].font_ = font_handle;
cache_[font_name].dc_ = hdc;
cache_[font_name].old_font_ = old_font;
cache_[font_name].ref_count_ += ref_count_inc;
}
void ReleaseCachedFonts(FontCacheDispatcher* dispatcher) {
typedef std::map<base::string16, FontCache::CacheElement> FontNameToElement;
base::AutoLock lock(mutex_);
DispatcherToFontNames::iterator it;
it = dispatcher_font_map_.find(dispatcher);
if (it == dispatcher_font_map_.end()) {
return;
}
for (FontNameVector::iterator i = it->second.begin(), e = it->second.end();
i != e; ++i) {
FontNameToElement::iterator element;
element = cache_.find(*i);
if (element != cache_.end()) {
--((*element).second.ref_count_);
}
}
dispatcher_font_map_.erase(it);
for (FontNameToElement::iterator i = cache_.begin(); i != cache_.end(); ) {
if (i->second.ref_count_ == 0) {
cache_.erase(i++);
} else {
++i;
}
}
}
private:
struct CacheElement {
CacheElement()
: font_(NULL), old_font_(NULL), dc_(NULL), ref_count_(0) {
}
~CacheElement() {
if (font_) {
if (dc_ && old_font_) {
SelectObject(dc_, old_font_);
}
DeleteObject(font_);
}
if (dc_) {
ReleaseDC(NULL, dc_);
}
}
HFONT font_;
HGDIOBJ old_font_;
HDC dc_;
int ref_count_;
};
friend struct DefaultSingletonTraits<FontCache>;
FontCache() {
}
std::map<base::string16, CacheElement> cache_;
DispatcherToFontNames dispatcher_font_map_;
base::Lock mutex_;
DISALLOW_COPY_AND_ASSIGN(FontCache);
};
}
FontCacheDispatcher::FontCacheDispatcher()
: sender_(NULL) {
}
bool FontCacheDispatcher::Send(IPC::Message* message) {
if (sender_)
return sender_->Send(message);
delete message;
return false;
}
FontCacheDispatcher::~FontCacheDispatcher() {
}
void FontCacheDispatcher::OnFilterAdded(IPC::Sender* sender) {
sender_ = sender;
}
bool FontCacheDispatcher::OnMessageReceived(const IPC::Message& message) {
bool handled = true;
IPC_BEGIN_MESSAGE_MAP(FontCacheDispatcher, message)
IPC_MESSAGE_HANDLER(ChildProcessHostMsg_PreCacheFont, OnPreCacheFont)
IPC_MESSAGE_HANDLER(ChildProcessHostMsg_ReleaseCachedFonts,
OnReleaseCachedFonts)
IPC_MESSAGE_UNHANDLED(handled = false)
IPC_END_MESSAGE_MAP()
return handled;
}
void FontCacheDispatcher::OnChannelClosing() {
sender_ = NULL;
}
void FontCacheDispatcher::OnPreCacheFont(const LOGFONT& font) {
// If a child process is running in a sandbox, GetTextMetrics()
// can sometimes fail. If a font has not been loaded
// previously, GetTextMetrics() will try to load the font
// from the font file. However, the sandboxed process does
// not have permissions to access any font files and
// the call fails. So we make the browser pre-load the
// font for us by using a dummy call to GetTextMetrics of
// the same font.
// This means the browser process just loads the font into memory so that
// when GDI attempt to query that font info in child process, it does not
// need to load that file, hence no permission issues there. Therefore,
// when a font is asked to be cached, we always recreates the font object
// to avoid the case that an in-cache font is swapped out by GDI.
FontCache::GetInstance()->PreCacheFont(font, this);
}
void FontCacheDispatcher::OnReleaseCachedFonts() {
// Release cached fonts that requested from a pid by decrementing the ref
// count. When ref count is zero, the handles are released.
FontCache::GetInstance()->ReleaseCachedFonts(this);
}
} // namespace content
|
