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/*
* Copyright (C) 2010 Igalia S.L.
*
* This library is free software; you can redistribute it and/or
* modify it under the terms of the GNU Lesser 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
* Lesser General Public License for more details.
*
* You should have received a copy of the GNU Lesser General Public
* License along with this library; if not, write to the Free Software
* Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
*/
#include "config.h"
#include "DOMObjectCache.h"
#include "Document.h"
#include "Node.h"
#include <glib-object.h>
#include <wtf/HashMap.h>
namespace WebKit {
typedef struct {
GObject* object;
WebCore::Frame* frame;
guint timesReturned;
} DOMObjectCacheData;
typedef HashMap<void*, DOMObjectCacheData*> DOMObjectMap;
static DOMObjectMap& domObjects()
{
static DOMObjectMap staticDOMObjects;
return staticDOMObjects;
}
static WebCore::Frame* getFrameFromHandle(void* objectHandle)
{
WebCore::Node* node = static_cast<WebCore::Node*>(objectHandle);
if (!node->inDocument())
return 0;
WebCore::Document* document = node->document();
if (!document)
return 0;
return document->frame();
}
void DOMObjectCache::forget(void* objectHandle)
{
DOMObjectCacheData* cacheData = domObjects().get(objectHandle);
ASSERT(cacheData);
g_slice_free(DOMObjectCacheData, cacheData);
domObjects().take(objectHandle);
}
static void weakRefNotify(gpointer data, GObject* zombie)
{
gboolean* objectDead = static_cast<gboolean*>(data);
*objectDead = TRUE;
}
void DOMObjectCache::clearByFrame(WebCore::Frame* frame)
{
Vector<DOMObjectCacheData*> toUnref;
// Unreffing the objects removes them from the cache in their
// finalize method, so just save them to do that while we are not
// iterating the cache itself.
DOMObjectMap::iterator end = domObjects().end();
for (DOMObjectMap::iterator iter = domObjects().begin(); iter != end; ++iter) {
DOMObjectCacheData* data = iter->value;
ASSERT(data);
if ((!frame || data->frame == frame) && data->timesReturned)
toUnref.append(data);
}
Vector<DOMObjectCacheData*>::iterator last = toUnref.end();
for (Vector<DOMObjectCacheData*>::iterator it = toUnref.begin(); it != last; ++it) {
DOMObjectCacheData* data = *it;
// We can't really know what the user has done with the DOM
// objects, so in case any of the external references to them
// were unreffed (but not all, otherwise the object would be
// dead and out of the cache) we'll add a weak ref before we
// start to get rid of the cache's own references; if the
// object dies in the middle of the process, we'll just stop.
gboolean objectDead = FALSE;
g_object_weak_ref(data->object, weakRefNotify, &objectDead);
// We need to check objectDead first, otherwise the cache data
// might be garbage already.
while (!objectDead && data->timesReturned > 0) {
// If this is the last unref we are going to do,
// disconnect the weak ref. We cannot do it afterwards
// because the object might be dead at that point.
if (data->timesReturned == 1) {
g_object_weak_unref(data->object, weakRefNotify, &objectDead);
// At this point, the next time the DOMObject is
// unref'ed it will be finalized,
// DOMObject::finalize() will call
// DOMObjectCache::forget(), which will free 'data'.
// Toggling 'objectDead' here will ensure we don't
// dereference an invalid pointer in the next
// iteration.
objectDead = TRUE;
}
data->timesReturned--;
g_object_unref(data->object);
}
}
}
DOMObjectCache::~DOMObjectCache()
{
clearByFrame();
}
void* DOMObjectCache::get(void* objectHandle)
{
DOMObjectCacheData* data = domObjects().get(objectHandle);
if (!data)
return 0;
// We want to add one ref each time a wrapper is returned, so that
// the user can manually unref them if he chooses to.
ASSERT(data->object);
data->timesReturned++;
return g_object_ref(data->object);
}
void* DOMObjectCache::put(void* objectHandle, void* wrapper)
{
if (domObjects().get(objectHandle))
return wrapper;
DOMObjectCacheData* data = g_slice_new(DOMObjectCacheData);
data->object = static_cast<GObject*>(wrapper);
data->frame = 0;
data->timesReturned = 1;
domObjects().set(objectHandle, data);
return wrapper;
}
void* DOMObjectCache::put(WebCore::Node* objectHandle, void* wrapper)
{
// call the ::put version that takes void* to do the basic cache
// insertion work
put(static_cast<void*>(objectHandle), wrapper);
DOMObjectCacheData* data = domObjects().get(objectHandle);
ASSERT(data);
data->frame = getFrameFromHandle(objectHandle);
return wrapper;
}
}
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