gecko/dom/bindings/CallbackObject.cpp
Bobby Holley c10703b2f4 Bug 877261 - Stop taking a cx in XPCWrappedJS::GetNewOrUsed. r=Ms2ger
Some of these callers seem to be passing a ccx when they don't need to, but
let's just remove the param all together for consistency.
2013-06-04 21:11:19 -07:00

213 lines
7.3 KiB
C++

/* -*- Mode: C++; tab-width: 2; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
/* vim:set ts=2 sw=2 sts=2 et cindent: */
/* This Source Code Form is subject to the terms of the Mozilla Public
* License, v. 2.0. If a copy of the MPL was not distributed with this
* file, You can obtain one at http://mozilla.org/MPL/2.0/. */
#include "mozilla/dom/CallbackObject.h"
#include "jsfriendapi.h"
#include "nsIScriptGlobalObject.h"
#include "nsIXPConnect.h"
#include "nsIScriptContext.h"
#include "nsPIDOMWindow.h"
#include "nsJSUtils.h"
#include "nsCxPusher.h"
#include "nsIScriptSecurityManager.h"
#include "xpcprivate.h"
namespace mozilla {
namespace dom {
NS_INTERFACE_MAP_BEGIN_CYCLE_COLLECTION(CallbackObject)
NS_INTERFACE_MAP_ENTRY(mozilla::dom::CallbackObject)
NS_INTERFACE_MAP_ENTRY(nsISupports)
NS_INTERFACE_MAP_END
NS_IMPL_CYCLE_COLLECTING_ADDREF(CallbackObject)
NS_IMPL_CYCLE_COLLECTING_RELEASE(CallbackObject)
NS_IMPL_CYCLE_COLLECTION_UNLINK_BEGIN(CallbackObject)
tmp->DropCallback();
NS_IMPL_CYCLE_COLLECTION_UNLINK_END
NS_IMPL_CYCLE_COLLECTION_TRAVERSE_BEGIN(CallbackObject)
NS_IMPL_CYCLE_COLLECTION_TRAVERSE_SCRIPT_OBJECTS
NS_IMPL_CYCLE_COLLECTION_TRAVERSE_END
NS_IMPL_CYCLE_COLLECTION_TRACE_BEGIN(CallbackObject)
NS_IMPL_CYCLE_COLLECTION_TRACE_JS_MEMBER_CALLBACK(mCallback)
NS_IMPL_CYCLE_COLLECTION_TRACE_END
CallbackObject::CallSetup::CallSetup(JS::Handle<JSObject*> aCallback,
ErrorResult& aRv,
ExceptionHandling aExceptionHandling)
: mCx(nullptr)
, mErrorResult(aRv)
, mExceptionHandling(aExceptionHandling)
{
xpc_UnmarkGrayObject(aCallback);
// We need to produce a useful JSContext here. Ideally one that the callback
// is in some sense associated with, so that we can sort of treat it as a
// "script entry point". Though once we actually have script entry points,
// we'll need to do the script entry point bits once we have an actual
// callable.
// First, find the real underlying callback.
JSObject* realCallback = js::UncheckedUnwrap(aCallback);
// Now get the nsIScriptGlobalObject for this callback.
JSContext* cx = nullptr;
nsIScriptContext* ctx = nullptr;
nsIScriptGlobalObject* sgo = nsJSUtils::GetStaticScriptGlobal(realCallback);
if (sgo) {
// Make sure that if this is a window it's the current inner, since the
// nsIScriptContext and hence JSContext are associated with the outer
// window. Which means that if someone holds on to a function from a
// now-unloaded document we'd have the new document as the script entry
// point...
nsCOMPtr<nsPIDOMWindow> win = do_QueryInterface(sgo);
if (win) {
MOZ_ASSERT(win->IsInnerWindow());
nsPIDOMWindow* outer = win->GetOuterWindow();
if (!outer || win != outer->GetCurrentInnerWindow()) {
// Just bail out from here
return;
}
}
// if not a window at all, just press on
ctx = sgo->GetContext();
if (ctx) {
// We don't check whether scripts are enabled on ctx, because
// CheckFunctionAccess will do that anyway... and because we ignore them
// being disabled if the callee is system.
cx = ctx->GetNativeContext();
}
}
if (!cx) {
// We didn't manage to hunt down a script global to work with. Just fall
// back on using the safe context.
cx = nsContentUtils::GetSafeJSContext();
}
// Go ahead and stick our callable in a Rooted, to make sure it can't go
// gray again. We can do this even though we're not in the right compartment
// yet, because Rooted<> does not care about compartments.
mRootedCallable.construct(cx, aCallback);
// Make sure our JSContext is pushed on the stack.
mCxPusher.Push(cx);
// After this point we guarantee calling ScriptEvaluated() if we
// have an nsIScriptContext.
// XXXbz Why, if, say CheckFunctionAccess fails? I know that's how
// nsJSContext::CallEventHandler used to work, but is it required?
// FIXME: Bug 807369.
mCtx = ctx;
// Check that it's ok to run this callback at all.
// FIXME: Bug 807371: we want a less silly check here.
// Make sure to unwrap aCallback before passing it in, because
// getting principals from wrappers is silly.
nsresult rv = nsContentUtils::GetSecurityManager()->
CheckFunctionAccess(cx, js::UncheckedUnwrap(aCallback), nullptr);
if (NS_FAILED(rv)) {
// Security check failed. We're done here.
return;
}
// Enter the compartment of our callback, so we can actually work with it.
mAc.construct(cx, aCallback);
// And now we're ready to go.
mCx = cx;
// Make sure the JS engine doesn't report exceptions we want to re-throw
if (mExceptionHandling == eRethrowExceptions) {
mSavedJSContextOptions = JS_GetOptions(cx);
JS_SetOptions(cx, mSavedJSContextOptions | JSOPTION_DONT_REPORT_UNCAUGHT);
}
}
CallbackObject::CallSetup::~CallSetup()
{
// First things first: if we have a JSContext, report any pending
// errors on it, unless we were told to re-throw them.
if (mCx) {
bool dealtWithPendingException = false;
if (mExceptionHandling == eRethrowExceptions) {
// Restore the old context options
JS_SetOptions(mCx, mSavedJSContextOptions);
mErrorResult.MightThrowJSException();
if (JS_IsExceptionPending(mCx)) {
JS::Rooted<JS::Value> exn(mCx);
if (JS_GetPendingException(mCx, exn.address())) {
mErrorResult.ThrowJSException(mCx, exn);
JS_ClearPendingException(mCx);
dealtWithPendingException = true;
}
}
}
if (!dealtWithPendingException) {
// Either we're supposed to report our exceptions, or we're supposed to
// re-throw them but we failed to JS_GetPendingException. Either way,
// just report the pending exception, if any.
nsJSUtils::ReportPendingException(mCx);
}
}
// If we have an mCtx, we need to call ScriptEvaluated() on it. But we have
// to do that after we pop the JSContext stack (see bug 295983). And to get
// our nesting right we have to destroy our JSAutoCompartment first. But be
// careful: it might not have been constructed at all!
mAc.destroyIfConstructed();
// XXXbz For that matter why do we need to manually call ScriptEvaluated at
// all? nsCxPusher::Pop will do that nowadays if !mScriptIsRunning, so the
// concerns from bug 295983 don't seem relevant anymore. Do we want to make
// sure it's still called when !mScriptIsRunning? I guess play it safe for
// now and do what CallEventHandler did, which is call always.
// Popping an nsCxPusher is safe even if it never got pushed.
mCxPusher.Pop();
if (mCtx) {
mCtx->ScriptEvaluated(true);
}
}
already_AddRefed<nsISupports>
CallbackObjectHolderBase::ToXPCOMCallback(CallbackObject* aCallback,
const nsIID& aIID) const
{
if (!aCallback) {
return nullptr;
}
AutoSafeJSContext cx;
JS::Rooted<JSObject*> callback(cx, aCallback->Callback());
JSAutoCompartment ac(cx, callback);
nsRefPtr<nsXPCWrappedJS> wrappedJS;
nsresult rv =
nsXPCWrappedJS::GetNewOrUsed(callback, aIID,
nullptr, getter_AddRefs(wrappedJS));
if (NS_FAILED(rv) || !wrappedJS) {
return nullptr;
}
nsCOMPtr<nsISupports> retval;
rv = wrappedJS->QueryInterface(aIID, getter_AddRefs(retval));
if (NS_FAILED(rv)) {
return nullptr;
}
return retval.forget();
}
} // namespace dom
} // namespace mozilla