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/*
* Copyright (C) 2006, 2009 Apple Inc. All rights reserved.
*
* This library is free software; you can redistribute it and/or
* modify it under the terms of the GNU Library General Public
* License as published by the Free Software Foundation; either
* version 2 of the License, or (at your option) any later version.
*
* This library is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
* Library General Public License for more details.
*
* You should have received a copy of the GNU Library General Public License
* along with this library; see the file COPYING.LIB. If not, write to
* the Free Software Foundation, Inc., 51 Franklin Street, Fifth Floor,
* Boston, MA 02110-1301, USA.
*
*/
#include "config.h"
#include "StringImpl.h"
#if PLATFORM(CF)
#include <CoreFoundation/CoreFoundation.h>
#include <wtf/MainThread.h>
#include <wtf/PassRefPtr.h>
#include <wtf/Threading.h>
#if PLATFORM(MAC) && !defined(BUILDING_ON_TIGER)
#include <objc/objc-auto.h>
#endif
namespace WebCore {
namespace StringWrapperCFAllocator {
static StringImpl* currentString;
static const void* retain(const void* info)
{
return info;
}
static void release(const void*)
{
ASSERT_NOT_REACHED();
}
static CFStringRef copyDescription(const void*)
{
return CFSTR("WebCore::String-based allocator");
}
static void* allocate(CFIndex size, CFOptionFlags, void*)
{
StringImpl* underlyingString = 0;
if (isMainThread()) {
underlyingString = currentString;
if (underlyingString) {
currentString = 0;
underlyingString->ref(); // Balanced by call to deref in deallocate below.
}
}
StringImpl** header = static_cast<StringImpl**>(fastMalloc(sizeof(StringImpl*) + size));
*header = underlyingString;
return header + 1;
}
static void* reallocate(void* pointer, CFIndex newSize, CFOptionFlags, void*)
{
size_t newAllocationSize = sizeof(StringImpl*) + newSize;
StringImpl** header = static_cast<StringImpl**>(pointer) - 1;
ASSERT(!*header);
header = static_cast<StringImpl**>(fastRealloc(header, newAllocationSize));
return header + 1;
}
static void deallocateOnMainThread(void* headerPointer)
{
StringImpl** header = static_cast<StringImpl**>(headerPointer);
StringImpl* underlyingString = *header;
ASSERT(underlyingString);
underlyingString->deref(); // Balanced by call to ref in allocate above.
fastFree(header);
}
static void deallocate(void* pointer, void*)
{
StringImpl** header = static_cast<StringImpl**>(pointer) - 1;
StringImpl* underlyingString = *header;
if (!underlyingString)
fastFree(header);
else {
if (!isMainThread())
callOnMainThread(deallocateOnMainThread, header);
else {
underlyingString->deref(); // Balanced by call to ref in allocate above.
fastFree(header);
}
}
}
static CFIndex preferredSize(CFIndex size, CFOptionFlags, void*)
{
// FIXME: If FastMalloc provided a "good size" callback, we'd want to use it here.
// Note that this optimization would help performance for strings created with the
// allocator that are mutable, and those typically are only created by callers who
// make a new string using the old string's allocator, such as some of the call
// sites in CFURL.
return size;
}
static CFAllocatorRef create()
{
#if PLATFORM(MAC) && !defined(BUILDING_ON_TIGER)
// Since garbage collection isn't compatible with custom allocators, don't use this at all when garbage collection is active.
if (objc_collectingEnabled())
return 0;
#endif
CFAllocatorContext context = { 0, 0, retain, release, copyDescription, allocate, reallocate, deallocate, preferredSize };
return CFAllocatorCreate(0, &context);
}
static CFAllocatorRef allocator()
{
static CFAllocatorRef allocator = create();
return allocator;
}
}
CFStringRef StringImpl::createCFString()
{
CFAllocatorRef allocator = (m_length && isMainThread()) ? StringWrapperCFAllocator::allocator() : 0;
if (!allocator)
return CFStringCreateWithCharacters(0, reinterpret_cast<const UniChar*>(m_data), m_length);
// Put pointer to the StringImpl in a global so the allocator can store it with the CFString.
ASSERT(!StringWrapperCFAllocator::currentString);
StringWrapperCFAllocator::currentString = this;
CFStringRef string = CFStringCreateWithCharactersNoCopy(allocator, reinterpret_cast<const UniChar*>(m_data), m_length, kCFAllocatorNull);
// The allocator cleared the global when it read it, but also clear it here just in case.
ASSERT(!StringWrapperCFAllocator::currentString);
StringWrapperCFAllocator::currentString = 0;
return string;
}
// On StringImpl creation we could check if the allocator is the StringWrapperCFAllocator.
// If it is, then we could find the original StringImpl and just return that. But to
// do that we'd have to compute the offset from CFStringRef to the allocated block;
// the CFStringRef is *not* at the start of an allocated block. Testing shows 1000x
// more calls to createCFString than calls to the create functions with the appropriate
// allocator, so it's probably not urgent optimize that case.
}
#endif // PLATFORM(CF)
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