2 * Copyright (C) 2006, 2009 Apple Inc. All rights reserved.
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.
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.
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.
22 #include <wtf/text/StringImpl.h>
26 #include <CoreFoundation/CoreFoundation.h>
27 #include <wtf/MainThread.h>
28 #include <wtf/PassRefPtr.h>
29 #include <wtf/Threading.h>
32 #include <objc/objc-auto.h>
37 namespace StringWrapperCFAllocator {
39 static StringImpl* currentString;
41 static const void* retain(const void* info)
46 NO_RETURN_DUE_TO_ASSERT
47 static void release(const void*)
52 static CFStringRef copyDescription(const void*)
54 return CFSTR("WTF::String-based allocator");
57 static void* allocate(CFIndex size, CFOptionFlags, void*)
59 StringImpl* underlyingString = 0;
61 underlyingString = currentString;
62 if (underlyingString) {
64 underlyingString->ref(); // Balanced by call to deref in deallocate below.
67 StringImpl** header = static_cast<StringImpl**>(fastMalloc(sizeof(StringImpl*) + size));
68 *header = underlyingString;
72 static void* reallocate(void* pointer, CFIndex newSize, CFOptionFlags, void*)
74 size_t newAllocationSize = sizeof(StringImpl*) + newSize;
75 StringImpl** header = static_cast<StringImpl**>(pointer) - 1;
77 header = static_cast<StringImpl**>(fastRealloc(header, newAllocationSize));
81 static void deallocateOnMainThread(void* headerPointer)
83 StringImpl** header = static_cast<StringImpl**>(headerPointer);
84 StringImpl* underlyingString = *header;
85 ASSERT(underlyingString);
86 underlyingString->deref(); // Balanced by call to ref in allocate above.
90 static void deallocate(void* pointer, void*)
92 StringImpl** header = static_cast<StringImpl**>(pointer) - 1;
93 StringImpl* underlyingString = *header;
94 if (!underlyingString)
98 callOnMainThread(deallocateOnMainThread, header);
100 underlyingString->deref(); // Balanced by call to ref in allocate above.
106 static CFIndex preferredSize(CFIndex size, CFOptionFlags, void*)
108 // FIXME: If FastMalloc provided a "good size" callback, we'd want to use it here.
109 // Note that this optimization would help performance for strings created with the
110 // allocator that are mutable, and those typically are only created by callers who
111 // make a new string using the old string's allocator, such as some of the call
116 static CFAllocatorRef create()
119 // Since garbage collection isn't compatible with custom allocators, don't use this at all when garbage collection is active.
120 if (objc_collectingEnabled())
123 CFAllocatorContext context = { 0, 0, retain, release, copyDescription, allocate, reallocate, deallocate, preferredSize };
124 return CFAllocatorCreate(0, &context);
127 static CFAllocatorRef allocator()
129 static CFAllocatorRef allocator = create();
135 CFStringRef StringImpl::createCFString()
137 CFAllocatorRef allocator = (m_length && isMainThread()) ? StringWrapperCFAllocator::allocator() : 0;
139 return CFStringCreateWithCharacters(0, reinterpret_cast<const UniChar*>(characters()), m_length);
141 // Put pointer to the StringImpl in a global so the allocator can store it with the CFString.
142 ASSERT(!StringWrapperCFAllocator::currentString);
143 StringWrapperCFAllocator::currentString = this;
145 CFStringRef string = CFStringCreateWithCharactersNoCopy(allocator, reinterpret_cast<const UniChar*>(characters()), m_length, kCFAllocatorNull);
147 // The allocator cleared the global when it read it, but also clear it here just in case.
148 ASSERT(!StringWrapperCFAllocator::currentString);
149 StringWrapperCFAllocator::currentString = 0;
154 // On StringImpl creation we could check if the allocator is the StringWrapperCFAllocator.
155 // If it is, then we could find the original StringImpl and just return that. But to
156 // do that we'd have to compute the offset from CFStringRef to the allocated block;
157 // the CFStringRef is *not* at the start of an allocated block. Testing shows 1000x
158 // more calls to createCFString than calls to the create functions with the appropriate
159 // allocator, so it's probably not urgent optimize that case.