The Tor Browser: js/xpconnect/src/XPCJSWeakReference.cpp@6474c204b198

Cloned upstream origin tor-browser at tor-browser-31.3.0esr-4.5-1-build1
revision ID fc1c9ff7c1b2defdbc039f12214767608f46423f for hacking purpose.

     1 /* -*- Mode: C++; tab-width: 8; indent-tabs-mode: nil; c-basic-offset: 4 -*- */

     2 /* vim: set ts=8 sts=4 et sw=4 tw=99: */

     3 /* This Source Code Form is subject to the terms of the Mozilla Public

     4  * License, v. 2.0. If a copy of the MPL was not distributed with this

     5  * file, You can obtain one at http://mozilla.org/MPL/2.0/. */

     7 #include "xpcprivate.h"

     8 #include "XPCJSWeakReference.h"

    10 #include "nsContentUtils.h"

    12 using namespace JS;

    14 xpcJSWeakReference::xpcJSWeakReference()

    15 {

    16 }

    18 NS_IMPL_ISUPPORTS(xpcJSWeakReference, xpcIJSWeakReference)

    20 nsresult xpcJSWeakReference::Init(JSContext* cx, const JS::Value& object)

    21 {

    22     if (!object.isObject())

    23         return NS_OK;

    25     JS::RootedObject obj(cx, &object.toObject());

    27     XPCCallContext ccx(NATIVE_CALLER, cx);

    29     // See if the object is a wrapped native that supports weak references.

    30     nsISupports* supports =

    31         nsXPConnect::XPConnect()->GetNativeOfWrapper(cx, obj);

    32     nsCOMPtr<nsISupportsWeakReference> supportsWeakRef =

    33         do_QueryInterface(supports);

    34     if (supportsWeakRef) {

    35         supportsWeakRef->GetWeakReference(getter_AddRefs(mReferent));

    36         if (mReferent) {

    37             return NS_OK;

    38         }

    39     }

    40     // If it's not a wrapped native, or it is a wrapped native that does not

    41     // support weak references, fall back to getting a weak ref to the object.

    43     // See if object is a wrapped JSObject.

    44     nsRefPtr<nsXPCWrappedJS> wrapped;

    45     nsresult rv = nsXPCWrappedJS::GetNewOrUsed(obj,

    46                                                NS_GET_IID(nsISupports),

    47                                                getter_AddRefs(wrapped));

    48     if (!wrapped) {

    49         NS_ERROR("can't get nsISupportsWeakReference wrapper for obj");

    50         return rv;

    51     }

    53     return wrapped->GetWeakReference(getter_AddRefs(mReferent));

    54 }

    56 NS_IMETHODIMP

    57 xpcJSWeakReference::Get(JSContext* aCx, MutableHandleValue aRetval)

    58 {

    59     aRetval.setNull();

    61     if (!mReferent) {

    62         return NS_OK;

    63     }

    65     nsCOMPtr<nsISupports> supports = do_QueryReferent(mReferent);

    66     if (!supports) {

    67         return NS_OK;

    68     }

    70     nsCOMPtr<nsIXPConnectWrappedJS> wrappedObj = do_QueryInterface(supports);

    71     if (!wrappedObj) {

    72         // We have a generic XPCOM object that supports weak references here.

    73         // Wrap it and pass it out.

    74         return nsContentUtils::WrapNative(aCx, supports,

    75                                           &NS_GET_IID(nsISupports),

    76                                           aRetval);

    77     }

    79     JS::RootedObject obj(aCx, wrappedObj->GetJSObject());

    80     if (!obj) {

    81         return NS_OK;

    82     }

    84     // Most users of XPCWrappedJS don't need to worry about

    85     // re-wrapping because things are implicitly rewrapped by

    86     // xpcconvert. However, because we're doing this directly

    87     // through the native call context, we need to call

    88     // JS_WrapObject().

    89     if (!JS_WrapObject(aCx, &obj)) {

    90         return NS_ERROR_FAILURE;

    91     }

    93     aRetval.setObject(*obj);

    94     return NS_OK;

    95 }

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