1 /*
2 * Copyright (C) 2006, 2009, 2012 Apple Inc. All rights reserved.
3 *
4 * This library is free software; you can redistribute it and/or
5 * modify it under the terms of the GNU Library General Public
6 * License as published by the Free Software Foundation; either
7 * version 2 of the License, or (at your option) any later version.
8 *
9 * This library is distributed in the hope that it will be useful,
10 * but WITHOUT ANY WARRANTY; without even the implied warranty of
11 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
12 * Library General Public License for more details.
13 *
14 * You should have received a copy of the GNU Library General Public License
15 * along with this library; see the file COPYING.LIB. If not, write to
16 * the Free Software Foundation, Inc., 51 Franklin Street, Fifth Floor,
17 * Boston, MA 02110-1301, USA.
18 *
19 */
20
21 #include "config.h"
22 #include "wtf/text/StringImpl.h"
23
24 #if USE(CF)
25
26 #include "wtf/MainThread.h"
27 #include "wtf/PassRefPtr.h"
28 #include "wtf/RetainPtr.h"
29 #include "wtf/Threading.h"
30 #include <CoreFoundation/CoreFoundation.h>
31
32 namespace WTF {
33
34 namespace StringWrapperCFAllocator {
35
36 static StringImpl* currentString;
37
retain(const void * info)38 static const void* retain(const void* info)
39 {
40 return info;
41 }
42
43 NO_RETURN_DUE_TO_ASSERT
release(const void *)44 static void release(const void*)
45 {
46 ASSERT_NOT_REACHED();
47 }
48
copyDescription(const void *)49 static CFStringRef copyDescription(const void*)
50 {
51 return CFSTR("WTF::String-based allocator");
52 }
53
allocate(CFIndex size,CFOptionFlags,void *)54 static void* allocate(CFIndex size, CFOptionFlags, void*)
55 {
56 StringImpl* underlyingString = 0;
57 if (isMainThread()) {
58 underlyingString = currentString;
59 if (underlyingString) {
60 currentString = 0;
61 underlyingString->ref(); // Balanced by call to deref in deallocate below.
62 }
63 }
64 StringImpl** header = static_cast<StringImpl**>(fastMalloc(sizeof(StringImpl*) + size));
65 *header = underlyingString;
66 return header + 1;
67 }
68
reallocate(void * pointer,CFIndex newSize,CFOptionFlags,void *)69 static void* reallocate(void* pointer, CFIndex newSize, CFOptionFlags, void*)
70 {
71 size_t newAllocationSize = sizeof(StringImpl*) + newSize;
72 StringImpl** header = static_cast<StringImpl**>(pointer) - 1;
73 ASSERT(!*header);
74 header = static_cast<StringImpl**>(fastRealloc(header, newAllocationSize));
75 return header + 1;
76 }
77
deallocateOnMainThread(void * headerPointer)78 static void deallocateOnMainThread(void* headerPointer)
79 {
80 StringImpl** header = static_cast<StringImpl**>(headerPointer);
81 StringImpl* underlyingString = *header;
82 ASSERT(underlyingString);
83 underlyingString->deref(); // Balanced by call to ref in allocate above.
84 fastFree(header);
85 }
86
deallocate(void * pointer,void *)87 static void deallocate(void* pointer, void*)
88 {
89 StringImpl** header = static_cast<StringImpl**>(pointer) - 1;
90 StringImpl* underlyingString = *header;
91 if (!underlyingString) {
92 fastFree(header);
93 } else {
94 if (!isMainThread()) {
95 callOnMainThread(deallocateOnMainThread, header);
96 } else {
97 underlyingString->deref(); // Balanced by call to ref in allocate above.
98 fastFree(header);
99 }
100 }
101 }
102
preferredSize(CFIndex size,CFOptionFlags,void *)103 static CFIndex preferredSize(CFIndex size, CFOptionFlags, void*)
104 {
105 // FIXME: If FastMalloc provided a "good size" callback, we'd want to use it here.
106 // Note that this optimization would help performance for strings created with the
107 // allocator that are mutable, and those typically are only created by callers who
108 // make a new string using the old string's allocator, such as some of the call
109 // sites in CFURL.
110 return size;
111 }
112
create()113 static CFAllocatorRef create()
114 {
115 CFAllocatorContext context = { 0, 0, retain, release, copyDescription, allocate, reallocate, deallocate, preferredSize };
116 return CFAllocatorCreate(0, &context);
117 }
118
allocator()119 static CFAllocatorRef allocator()
120 {
121 static CFAllocatorRef allocator = create();
122 return allocator;
123 }
124
125 }
126
createCFString()127 RetainPtr<CFStringRef> StringImpl::createCFString()
128 {
129 // Since garbage collection isn't compatible with custom allocators, we
130 // can't use the NoCopy variants of CFStringCreate*() when GC is enabled.
131 if (!m_length || !isMainThread()) {
132 if (is8Bit())
133 return adoptCF(CFStringCreateWithBytes(0, reinterpret_cast<const UInt8*>(characters8()), m_length, kCFStringEncodingISOLatin1, false));
134 return adoptCF(CFStringCreateWithCharacters(0, reinterpret_cast<const UniChar*>(characters16()), m_length));
135 }
136 CFAllocatorRef allocator = StringWrapperCFAllocator::allocator();
137
138 // Put pointer to the StringImpl in a global so the allocator can store it with the CFString.
139 ASSERT(!StringWrapperCFAllocator::currentString);
140 StringWrapperCFAllocator::currentString = this;
141
142 CFStringRef string;
143 if (is8Bit())
144 string = CFStringCreateWithBytesNoCopy(allocator, reinterpret_cast<const UInt8*>(characters8()), m_length, kCFStringEncodingISOLatin1, false, kCFAllocatorNull);
145 else
146 string = CFStringCreateWithCharactersNoCopy(allocator, reinterpret_cast<const UniChar*>(characters16()), m_length, kCFAllocatorNull);
147 // CoreFoundation might not have to allocate anything, we clear currentString in case we did not execute allocate().
148 StringWrapperCFAllocator::currentString = 0;
149
150 return adoptCF(string);
151 }
152
153 // On StringImpl creation we could check if the allocator is the StringWrapperCFAllocator.
154 // If it is, then we could find the original StringImpl and just return that. But to
155 // do that we'd have to compute the offset from CFStringRef to the allocated block;
156 // the CFStringRef is *not* at the start of an allocated block. Testing shows 1000x
157 // more calls to createCFString than calls to the create functions with the appropriate
158 // allocator, so it's probably not urgent optimize that case.
159
160 }
161
162 #endif // USE(CF)
163