WebKit/Source/JavaScriptCore/API/glib/JSCWeakValue.cpp at main · WebKit/WebKit · GitHub

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* 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 "JSCWeakValue.h"

#include "APICast.h"

#include "JSCContextPrivate.h"

#include "JSCInlines.h"

#include "JSCValuePrivate.h"

#include "JSWeakValue.h"

#include "WeakHandleOwner.h"

#include <wtf/glib/GRefPtr.h>

#include <wtf/glib/GUniquePtr.h>

#include <wtf/glib/WTFGType.h>

/**

* JSCWeakValue:

* @short_description: JavaScript weak value

* @title: JSCWeakValue

* @see_also: JSCValue

* JSCWeakValue represents a weak reference to a value in a #JSCContext. It can be used

* to keep a reference to a JavaScript value without protecting it from being garbage

* collected and without referencing the #JSCContext either.

enum {

PROP_0,

PROP_VALUE,

};

enum {

CLEARED,

LAST_SIGNAL

};

struct _JSCWeakValuePrivate {

JSC::Weak<JSC::JSGlobalObject> globalObject;

RefPtr<JSC::JSLock> lock;

JSC::JSWeakValue weakValueRef;

};

static std::array<unsigned, LAST_SIGNAL> signals;

WEBKIT_DEFINE_FINAL_TYPE(JSCWeakValue, jsc_weak_value, G_TYPE_OBJECT, GObject)

static void jscWeakValueClear(JSCWeakValue* weakValue)

{

JSCWeakValuePrivate* priv = weakValue->priv;

priv->globalObject.clear();

priv->weakValueRef.clear();

}

class JSCWeakValueHandleOwner final : public JSC::WeakHandleOwner {

public:

void finalize(JSC::Handle<JSC::Unknown>, void* context) final

{

auto* weakValue = JSC_WEAK_VALUE(context);

jscWeakValueClear(weakValue);

g_signal_emit(weakValue, signals[CLEARED], 0, nullptr);

}

};

static JSCWeakValueHandleOwner& weakValueHandleOwner()

{

static NeverDestroyed<JSCWeakValueHandleOwner> jscWeakValueHandleOwner;

return jscWeakValueHandleOwner;

}

static void jscWeakValueInitialize(JSCWeakValue* weakValue, JSCValue* value)

{

JSCWeakValuePrivate* priv = weakValue->priv;

auto* jsContext = jscContextGetJSContext(jsc_value_get_context(value));

JSC::JSGlobalObject* globalObject = toJS(jsContext);

JSC::JSLockHolder locker(globalObject->vm());

auto& owner = weakValueHandleOwner();

JSC::Weak<JSC::JSGlobalObject> weak(globalObject, &owner, weakValue);

priv->globalObject.swap(weak);

priv->lock = &globalObject->vm().apiLock();

JSC::JSValue jsValue = toJS(globalObject, jscValueGetJSValue(value));

if (jsValue.isObject())

priv->weakValueRef.setObject(uncheckedDowncast<JSC::JSObject>(jsValue.asCell()), owner, weakValue);

else if (jsValue.isString())

priv->weakValueRef.setString(uncheckedDowncast<JSC::JSString>(jsValue.asCell()), owner, weakValue);

else

priv->weakValueRef.setPrimitive(jsValue);

}

static void jscWeakValueSetProperty(GObject* object, guint propID, const GValue* value, GParamSpec* paramSpec)

{

switch (propID) {

case PROP_VALUE:

jscWeakValueInitialize(JSC_WEAK_VALUE(object), JSC_VALUE(g_value_get_object(value)));

break;

default:

G_OBJECT_WARN_INVALID_PROPERTY_ID(object, propID, paramSpec);

}

static void jscWeakValueDispose(GObject* object)

{

JSCWeakValue* weakValue = JSC_WEAK_VALUE(object);

jscWeakValueClear(weakValue);

G_OBJECT_CLASS(jsc_weak_value_parent_class)->dispose(object);

}

static void jsc_weak_value_class_init(JSCWeakValueClass* klass)

{

GObjectClass* objClass = G_OBJECT_CLASS(klass);

objClass->set_property = jscWeakValueSetProperty;

objClass->dispose = jscWeakValueDispose;

/**

* JSCWeakValue:value:

* The #JSCValue referencing the JavaScript value.

g_object_class_install_property(objClass,

PROP_VALUE,

g_param_spec_object(

"value",

nullptr, nullptr,

JSC_TYPE_VALUE,

static_cast<GParamFlags>(WEBKIT_PARAM_WRITABLE | G_PARAM_CONSTRUCT_ONLY)));

/**

* JSCWeakValue::cleared:

* @weak_value: the #JSCWeakValue

* This signal is emitted when the JavaScript value is destroyed.

signals[CLEARED] = g_signal_new(

"cleared",

G_TYPE_FROM_CLASS(klass),

G_SIGNAL_RUN_LAST,

0, nullptr, nullptr,

g_cclosure_marshal_generic,

G_TYPE_NONE, 0,

G_TYPE_NONE);

}

/**

* jsc_weak_value_new:

* @value: a #JSCValue

* Create a new #JSCWeakValue for the JavaScript value referenced by @value.

* Returns: (transfer full): a new #JSCWeakValue

JSCWeakValue* jsc_weak_value_new(JSCValue* value)

{

g_return_val_if_fail(JSC_IS_VALUE(value), nullptr);

return JSC_WEAK_VALUE(g_object_new(JSC_TYPE_WEAK_VALUE, "value", value, nullptr));

}

/**

* jsc_weak_value_get_value:

* @weak_value: a #JSCWeakValue

* Get a #JSCValue referencing the JavaScript value of @weak_value.

* Returns: (transfer full): a new #JSCValue or %NULL if @weak_value was cleared.

JSCValue* jsc_weak_value_get_value(JSCWeakValue* weakValue)

{

g_return_val_if_fail(JSC_IS_WEAK_VALUE(weakValue), nullptr);

JSCWeakValuePrivate* priv = weakValue->priv;

WTF::Locker<JSC::JSLock> locker(priv->lock.get());

RefPtr vm = priv->lock->vm();

if (!vm)

return nullptr;

JSC::JSLockHolder apiLocker(vm.get());

if (!priv->globalObject || priv->weakValueRef.isClear())

return nullptr;

JSC::JSValue value;

if (priv->weakValueRef.isPrimitive())

value = priv->weakValueRef.primitive();

else if (priv->weakValueRef.isString())

value = priv->weakValueRef.string();

else

value = priv->weakValueRef.object();

JSC::JSGlobalObject* globalObject = priv->globalObject.get();

GRefPtr<JSCContext> context = jscContextGetOrCreate(toGlobalRef(globalObject));

return jscContextGetOrCreateValue(context.get(), toRef(globalObject, value)).leakRef();

}

WebKit/Source/JavaScriptCore/API/glib/JSCWeakValue.cpp at main · WebKit/WebKit · GitHub

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