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/* -*- Mode: C++; tab-width: 8; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
/* vim: set ts=8 sts=2 et sw=2 tw=80: */
/* 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
#include "mozilla/dom/ScriptSettings.h"
#include <utility>
#include "MainThreadUtils.h"
#include "js/CharacterEncoding.h"
#include "js/CompilationAndEvaluation.h"
#include "js/Conversions.h"
#include "js/ErrorReport.h"
#include "js/Exception.h"
#include "js/GCAPI.h"
#include "js/PropertyAndElement.h" // JS_GetProperty
#include "js/TypeDecls.h"
#include "js/Value.h"
#include "js/Warnings.h"
#include "js/Wrapper.h"
#include "js/friend/ErrorMessages.h"
#include "js/loader/LoadedScript.h"
#include "js/loader/ScriptLoadRequest.h"
#include "jsapi.h"
#include "mozilla/Assertions.h"
#include "mozilla/BasePrincipal.h"
#include "mozilla/CycleCollectedJSContext.h"
#include "mozilla/DebugOnly.h"
#include "mozilla/Maybe.h"
#include "mozilla/RefPtr.h"
#include "mozilla/ThreadLocal.h"
#include "mozilla/dom/AutoEntryScript.h"
#include "mozilla/dom/BindingUtils.h"
#include "mozilla/dom/Document.h"
#include "mozilla/dom/Element.h"
#include "mozilla/dom/WorkerCommon.h"
#include "nsContentUtils.h"
#include "nsDebug.h"
#include "nsGlobalWindowInner.h"
#include "nsIGlobalObject.h"
#include "nsINode.h"
#include "nsIPrincipal.h"
#include "nsISupports.h"
#include "nsJSUtils.h"
#include "nsPIDOMWindow.h"
#include "nsString.h"
#include "nscore.h"
#include "xpcpublic.h"
namespace mozilla {
namespace dom {
static MOZ_THREAD_LOCAL(ScriptSettingsStackEntry*) sScriptSettingsTLS;
class ScriptSettingsStack {
public:
static ScriptSettingsStackEntry* Top() { return sScriptSettingsTLS.get(); }
static void Push(ScriptSettingsStackEntry* aEntry) {
MOZ_ASSERT(!aEntry->mOlder);
// Whenever JSAPI use is disabled, the next stack entry pushed must
// not be an AutoIncumbentScript.
MOZ_ASSERT_IF(!Top() || Top()->NoJSAPI(), !aEntry->IsIncumbentScript());
// Whenever the top entry is not an incumbent canidate, the next stack entry
// pushed must not be an AutoIncumbentScript.
MOZ_ASSERT_IF(Top() && !Top()->IsIncumbentCandidate(),
!aEntry->IsIncumbentScript());
aEntry->mOlder = Top();
sScriptSettingsTLS.set(aEntry);
}
static void Pop(ScriptSettingsStackEntry* aEntry) {
MOZ_ASSERT(aEntry == Top());
sScriptSettingsTLS.set(aEntry->mOlder);
}
static nsIGlobalObject* IncumbentGlobal() {
ScriptSettingsStackEntry* entry = Top();
while (entry) {
if (entry->IsIncumbentCandidate()) {
return entry->mGlobalObject;
}
entry = entry->mOlder;
}
return nullptr;
}
static ScriptSettingsStackEntry* EntryPoint() {
ScriptSettingsStackEntry* entry = Top();
while (entry) {
if (entry->IsEntryCandidate()) {
return entry;
}
entry = entry->mOlder;
}
return nullptr;
}
static nsIGlobalObject* EntryGlobal() {
ScriptSettingsStackEntry* entry = EntryPoint();
if (!entry) {
return nullptr;
}
return entry->mGlobalObject;
}
#ifdef DEBUG
static ScriptSettingsStackEntry* TopNonIncumbentScript() {
ScriptSettingsStackEntry* entry = Top();
while (entry) {
if (!entry->IsIncumbentScript()) {
return entry;
}
entry = entry->mOlder;
}
return nullptr;
}
#endif // DEBUG
};
void InitScriptSettings() {
bool success = sScriptSettingsTLS.init();
if (!success) {
MOZ_CRASH();
}
sScriptSettingsTLS.set(nullptr);
}
void DestroyScriptSettings() {
MOZ_ASSERT(sScriptSettingsTLS.get() == nullptr);
}
ScriptSettingsStackEntry::ScriptSettingsStackEntry(nsIGlobalObject* aGlobal,
Type aType)
: mGlobalObject(aGlobal), mType(aType), mOlder(nullptr) {
MOZ_ASSERT_IF(IsIncumbentCandidate() && !NoJSAPI(), mGlobalObject);
MOZ_ASSERT(!mGlobalObject || mGlobalObject->HasJSGlobal(),
"Must have an actual JS global for the duration on the stack");
MOZ_ASSERT(
!mGlobalObject ||
JS_IsGlobalObject(mGlobalObject->GetGlobalJSObjectPreserveColor()),
"No outer windows allowed");
}
ScriptSettingsStackEntry::~ScriptSettingsStackEntry() {
// We must have an actual JS global for the entire time this is on the stack.
MOZ_ASSERT_IF(mGlobalObject, mGlobalObject->HasJSGlobal());
}
// If the entry or incumbent global ends up being something that the subject
// principal doesn't subsume, we don't want to use it. This never happens on
// the web, but can happen with asymmetric privilege relationships (i.e.
// ExpandedPrincipal and System Principal).
//
// The most correct thing to use instead would be the topmost global on the
// callstack whose principal is subsumed by the subject principal. But that's
// hard to compute, so we just substitute the global of the current
// compartment. In practice, this is fine.
//
// Note that in particular things like:
//
// |SpecialPowers.wrap(crossOriginWindow).eval(open())|
//
// trigger this case. Although both the entry global and the current global
// have normal principals, the use of Gecko-specific System-Principaled JS
// puts the code from two different origins on the callstack at once, which
// doesn't happen normally on the web.
static nsIGlobalObject* ClampToSubject(nsIGlobalObject* aGlobalOrNull) {
if (!aGlobalOrNull || !NS_IsMainThread()) {
return aGlobalOrNull;
}
nsIPrincipal* globalPrin = aGlobalOrNull->PrincipalOrNull();
NS_ENSURE_TRUE(globalPrin, GetCurrentGlobal());
if (!nsContentUtils::SubjectPrincipalOrSystemIfNativeCaller()
->SubsumesConsideringDomain(globalPrin)) {
return GetCurrentGlobal();
}
return aGlobalOrNull;
}
nsIGlobalObject* GetEntryGlobal() {
return ClampToSubject(ScriptSettingsStack::EntryGlobal());
}
Document* GetEntryDocument() {
nsIGlobalObject* global = GetEntryGlobal();
nsCOMPtr<nsPIDOMWindowInner> entryWin = do_QueryInterface(global);
return entryWin ? entryWin->GetExtantDoc() : nullptr;
}
nsIGlobalObject* GetIncumbentGlobal() {
// We need the current JSContext in order to check the JS for
// scripted frames that may have appeared since anyone last
// manipulated the stack. If it's null, that means that there
// must be no entry global on the stack, and therefore no incumbent
// global either.
JSContext* cx = nsContentUtils::GetCurrentJSContext();
if (!cx) {
MOZ_ASSERT(ScriptSettingsStack::EntryGlobal() == nullptr);
return nullptr;
}
// See what the JS engine has to say. If we've got a scripted caller
// override in place, the JS engine will lie to us and pretend that
// there's nothing on the JS stack, which will cause us to check the
// incumbent script stack below.
if (JSObject* global = JS::GetScriptedCallerGlobal(cx)) {
return ClampToSubject(xpc::NativeGlobal(global));
}
// Ok, nothing from the JS engine. Let's use whatever's on the
// explicit stack.
return ClampToSubject(ScriptSettingsStack::IncumbentGlobal());
}
nsIGlobalObject* GetCurrentGlobal() {
JSContext* cx = nsContentUtils::GetCurrentJSContext();
if (!cx) {
return nullptr;
}
JSObject* global = JS::CurrentGlobalOrNull(cx);
if (!global) {
return nullptr;
}
return xpc::NativeGlobal(global);
}
nsIPrincipal* GetWebIDLCallerPrincipal() {
MOZ_ASSERT(NS_IsMainThread());
ScriptSettingsStackEntry* entry = ScriptSettingsStack::EntryPoint();
// If we have an entry point that is not NoJSAPI, we know it must be an
// AutoEntryScript.
if (!entry || entry->NoJSAPI()) {
return nullptr;
}
AutoEntryScript* aes = static_cast<AutoEntryScript*>(entry);
return aes->mWebIDLCallerPrincipal;
}
bool IsJSAPIActive() {
ScriptSettingsStackEntry* topEntry = ScriptSettingsStack::Top();
return topEntry && !topEntry->NoJSAPI();
}
namespace danger {
JSContext* GetJSContext() { return CycleCollectedJSContext::Get()->Context(); }
} // namespace danger
JS::RootingContext* RootingCx() {
return CycleCollectedJSContext::Get()->RootingCx();
}
AutoJSAPI::AutoJSAPI()
: ScriptSettingsStackEntry(nullptr, eJSAPI),
mCx(nullptr),
mIsMainThread(false) // For lack of anything better
{}
AutoJSAPI::~AutoJSAPI() {
if (!mCx) {
// No need to do anything here: we never managed to Init, so can't have an
// exception on our (nonexistent) JSContext. We also don't need to restore
// any state on it. Finally, we never made it to pushing ourselves onto the
// ScriptSettingsStack, so shouldn't pop.
MOZ_ASSERT(ScriptSettingsStack::Top() != this);
return;
}
ReportException();
if (mOldWarningReporter.isSome()) {
JS::SetWarningReporter(cx(), mOldWarningReporter.value());
}
ScriptSettingsStack::Pop(this);
}
void WarningOnlyErrorReporter(JSContext* aCx, JSErrorReport* aRep);
void AutoJSAPI::InitInternal(nsIGlobalObject* aGlobalObject, JSObject* aGlobal,
JSContext* aCx, bool aIsMainThread) {
MOZ_ASSERT(aCx);
MOZ_ASSERT(aCx == danger::GetJSContext());
MOZ_ASSERT(aIsMainThread == NS_IsMainThread());
MOZ_ASSERT(bool(aGlobalObject) == bool(aGlobal));
MOZ_ASSERT_IF(aGlobalObject,
aGlobalObject->GetGlobalJSObjectPreserveColor() == aGlobal);
#ifdef DEBUG
bool haveException = JS_IsExceptionPending(aCx);
#endif // DEBUG
mCx = aCx;
mIsMainThread = aIsMainThread;
if (aGlobal) {
JS::AssertObjectIsNotGray(aGlobal);
}
mAutoNullableRealm.emplace(mCx, aGlobal);
mGlobalObject = aGlobalObject;
ScriptSettingsStack::Push(this);
mOldWarningReporter.emplace(JS::GetWarningReporter(aCx));
JS::SetWarningReporter(aCx, WarningOnlyErrorReporter);
#ifdef DEBUG
if (haveException) {
JS::Rooted<JS::Value> exn(aCx);
JS_GetPendingException(aCx, &exn);
JS_ClearPendingException(aCx);
if (exn.isObject()) {
JS::Rooted<JSObject*> exnObj(aCx, &exn.toObject());
// Make sure we can actually read things from it. This UncheckedUwrap is
// safe because we're only getting data for a debug printf. In
// particular, we do not expose this data to anyone, which is very
// important; otherwise it could be a cross-origin information leak.
exnObj = js::UncheckedUnwrap(exnObj);
JSAutoRealm ar(aCx, exnObj);
nsAutoJSString stack, filename, name, message;
int32_t line;
JS::Rooted<JS::Value> tmp(aCx);
if (!JS_GetProperty(aCx, exnObj, "filename", &tmp)) {
JS_ClearPendingException(aCx);
}
if (tmp.isUndefined()) {
if (!JS_GetProperty(aCx, exnObj, "fileName", &tmp)) {
JS_ClearPendingException(aCx);
}
}
if (!filename.init(aCx, tmp)) {
JS_ClearPendingException(aCx);
}
if (!JS_GetProperty(aCx, exnObj, "stack", &tmp) ||
!stack.init(aCx, tmp)) {
JS_ClearPendingException(aCx);
}
if (!JS_GetProperty(aCx, exnObj, "name", &tmp) || !name.init(aCx, tmp)) {
JS_ClearPendingException(aCx);
}
if (!JS_GetProperty(aCx, exnObj, "message", &tmp) ||
!message.init(aCx, tmp)) {
JS_ClearPendingException(aCx);
}
if (!JS_GetProperty(aCx, exnObj, "lineNumber", &tmp) ||
!JS::ToInt32(aCx, tmp, &line)) {
JS_ClearPendingException(aCx);
line = 0;
}
printf_stderr("PREEXISTING EXCEPTION OBJECT: '%s: %s'\n%s:%d\n%s\n",
NS_ConvertUTF16toUTF8(name).get(),
NS_ConvertUTF16toUTF8(message).get(),
NS_ConvertUTF16toUTF8(filename).get(), line,
NS_ConvertUTF16toUTF8(stack).get());
} else {
// It's a primitive... not much we can do other than stringify it.
nsAutoJSString exnStr;
if (!exnStr.init(aCx, exn)) {
JS_ClearPendingException(aCx);
}
printf_stderr("PREEXISTING EXCEPTION PRIMITIVE: %s\n",
NS_ConvertUTF16toUTF8(exnStr).get());
}
MOZ_ASSERT(false, "We had an exception; we should not have");
}
#endif // DEBUG
}
AutoJSAPI::AutoJSAPI(nsIGlobalObject* aGlobalObject, bool aIsMainThread,
Type aType)
: ScriptSettingsStackEntry(aGlobalObject, aType),
mIsMainThread(aIsMainThread) {
MOZ_ASSERT(aGlobalObject);
MOZ_ASSERT(aGlobalObject->HasJSGlobal(), "Must have a JS global");
MOZ_ASSERT(aIsMainThread == NS_IsMainThread());
InitInternal(aGlobalObject, aGlobalObject->GetGlobalJSObject(),
danger::GetJSContext(), aIsMainThread);
}
void AutoJSAPI::Init() {
MOZ_ASSERT(!mCx, "An AutoJSAPI should only be initialised once");
InitInternal(/* aGlobalObject */ nullptr, /* aGlobal */ nullptr,
danger::GetJSContext(), NS_IsMainThread());
}
bool AutoJSAPI::Init(nsIGlobalObject* aGlobalObject, JSContext* aCx) {
MOZ_ASSERT(!mCx, "An AutoJSAPI should only be initialised once");
MOZ_ASSERT(aCx);
if (NS_WARN_IF(!aGlobalObject)) {
return false;
}
JSObject* global = aGlobalObject->GetGlobalJSObject();
if (NS_WARN_IF(!global)) {
return false;
}
InitInternal(aGlobalObject, global, aCx, NS_IsMainThread());
return true;
}
bool AutoJSAPI::Init(nsIGlobalObject* aGlobalObject) {
return Init(aGlobalObject, danger::GetJSContext());
}
bool AutoJSAPI::Init(JSObject* aObject) {
MOZ_ASSERT(!js::IsCrossCompartmentWrapper(aObject));
return Init(xpc::NativeGlobal(aObject));
}
bool AutoJSAPI::Init(nsPIDOMWindowInner* aWindow, JSContext* aCx) {
return Init(nsGlobalWindowInner::Cast(aWindow), aCx);
}
bool AutoJSAPI::Init(nsPIDOMWindowInner* aWindow) {
return Init(nsGlobalWindowInner::Cast(aWindow));
}
bool AutoJSAPI::Init(nsGlobalWindowInner* aWindow, JSContext* aCx) {
return Init(static_cast<nsIGlobalObject*>(aWindow), aCx);
}
bool AutoJSAPI::Init(nsGlobalWindowInner* aWindow) {
return Init(static_cast<nsIGlobalObject*>(aWindow));
}
// Even with autoJSAPIOwnsErrorReporting, the JS engine still sends warning
// reports to the JSErrorReporter as soon as they are generated. These go
// directly to the console, so we can handle them easily here.
//
// Eventually, SpiderMonkey will have a special-purpose callback for warnings
// only.
void WarningOnlyErrorReporter(JSContext* aCx, JSErrorReport* aRep) {
MOZ_ASSERT(aRep->isWarning());
if (!NS_IsMainThread()) {
// Reporting a warning on workers is a bit complicated because we have to
// climb our parent chain until we get to the main thread. So go ahead and
// just go through the worker or worklet ReportError codepath here.
//
// That said, it feels like we should be able to short-circuit things a bit
// here by posting an appropriate runnable to the main thread directly...
// Worth looking into sometime.
CycleCollectedJSContext* ccjscx = CycleCollectedJSContext::GetFor(aCx);
MOZ_ASSERT(ccjscx);
ccjscx->ReportError(aRep, JS::ConstUTF8CharsZ());
return;
}
RefPtr<xpc::ErrorReport> xpcReport = new xpc::ErrorReport();
nsGlobalWindowInner* win = xpc::CurrentWindowOrNull(aCx);
xpcReport->Init(aRep, nullptr, nsContentUtils::IsSystemCaller(aCx),
win ? win->WindowID() : 0);
xpcReport->LogToConsole();
}
void AutoJSAPI::ReportException() {
if (!HasException()) {
return;
}
// AutoJSAPI uses a JSAutoNullableRealm, and may be in a null realm
// when the destructor is called. However, the JS engine requires us
// to be in a realm when we fetch the pending exception. In this case,
// we enter the privileged junk scope and don't dispatch any error events.
JS::Rooted<JSObject*> errorGlobal(cx(), JS::CurrentGlobalOrNull(cx()));
if (!errorGlobal) {
if (mIsMainThread) {
errorGlobal = xpc::PrivilegedJunkScope();
} else {
errorGlobal = GetCurrentThreadWorkerGlobal();
if (!errorGlobal) {
// We might be reporting an error in debugger code that ran before the
// worker's global was created. Use the debugger global instead.
errorGlobal = GetCurrentThreadWorkerDebuggerGlobal();
if (NS_WARN_IF(!errorGlobal)) {
// An exception may have been thrown on attempt to create a global
// and now there is no realm from which to fetch the exception.
// Give up.
ClearException();
return;
}
}
}
}
MOZ_ASSERT(JS_IsGlobalObject(errorGlobal));
JSAutoRealm ar(cx(), errorGlobal);
JS::ExceptionStack exnStack(cx());
JS::ErrorReportBuilder jsReport(cx());
if (StealExceptionAndStack(&exnStack) &&
jsReport.init(cx(), exnStack, JS::ErrorReportBuilder::WithSideEffects)) {
if (mIsMainThread) {
RefPtr<xpc::ErrorReport> xpcReport = new xpc::ErrorReport();
RefPtr<nsGlobalWindowInner> inner = xpc::WindowOrNull(errorGlobal);
// For WebExtension content script, `WindowOrNull` method will return
// null, whereas we would still like to flag the exception with the
// related WindowGlobal the content script executed against. So we only
// update the `innerWindowID` and not `inner` as we don't want to dispatch
// exceptions caused by the content script to the webpage.
uint64_t innerWindowID = 0;
if (inner) {
innerWindowID = inner->WindowID();
} else if (nsGlobalWindowInner* win = xpc::SandboxWindowOrNull(
JS::GetNonCCWObjectGlobal(errorGlobal), cx())) {
innerWindowID = win->WindowID();
}
bool isChrome =
nsContentUtils::ObjectPrincipal(errorGlobal)->IsSystemPrincipal();
xpcReport->Init(jsReport.report(), jsReport.toStringResult().c_str(),
isChrome, innerWindowID);
if (inner && jsReport.report()->errorNumber != JSMSG_OUT_OF_MEMORY) {
JS::RootingContext* rcx = JS::RootingContext::get(cx());
DispatchScriptErrorEvent(inner, rcx, xpcReport, exnStack.exception(),
exnStack.stack());
} else {
JS::Rooted<JSObject*> stack(cx());
JS::Rooted<JSObject*> stackGlobal(cx());
xpc::FindExceptionStackForConsoleReport(inner, exnStack.exception(),
exnStack.stack(), &stack,
&stackGlobal);
// This error is not associated with a specific window,
// so omit the exception value to mitigate potential leaks.
xpcReport->LogToConsoleWithStack(inner, JS::NothingHandleValue, stack,
stackGlobal);
}
} else {
// On a worker or worklet, we just use the error reporting mechanism and
// don't bother with xpc::ErrorReport. This will ensure that all the
// right worker events (which are a lot more complicated than in the
// window case) get fired.
CycleCollectedJSContext* ccjscx = CycleCollectedJSContext::GetFor(cx());
MOZ_ASSERT(ccjscx);
// Before invoking ReportError, put the exception back on the context,
// because it may want to put it in its error events and has no other way
// to get hold of it. After we invoke ReportError, clear the exception on
// cx(), just in case ReportError didn't.
JS::SetPendingExceptionStack(cx(), exnStack);
ccjscx->ReportError(jsReport.report(), jsReport.toStringResult());
ClearException();
}
} else {
NS_WARNING("OOMed while acquiring uncaught exception from JSAPI");
ClearException();
}
}
bool AutoJSAPI::PeekException(JS::MutableHandle<JS::Value> aVal) {
MOZ_ASSERT_IF(mIsMainThread, IsStackTop());
MOZ_ASSERT(HasException());
MOZ_ASSERT(js::GetContextRealm(cx()));
return JS_GetPendingException(cx(), aVal);
}
bool AutoJSAPI::StealException(JS::MutableHandle<JS::Value> aVal) {
JS::ExceptionStack exnStack(cx());
if (!StealExceptionAndStack(&exnStack)) {
return false;
}
aVal.set(exnStack.exception());
return true;
}
bool AutoJSAPI::StealExceptionAndStack(JS::ExceptionStack* aExnStack) {
MOZ_ASSERT_IF(mIsMainThread, IsStackTop());
MOZ_ASSERT(HasException());
MOZ_ASSERT(js::GetContextRealm(cx()));
return JS::StealPendingExceptionStack(cx(), aExnStack);
}
#ifdef DEBUG
bool AutoJSAPI::IsStackTop() const {
return ScriptSettingsStack::TopNonIncumbentScript() == this;
}
#endif // DEBUG
AutoIncumbentScript::AutoIncumbentScript(nsIGlobalObject* aGlobalObject)
: ScriptSettingsStackEntry(aGlobalObject, eIncumbentScript),
mCallerOverride(nsContentUtils::GetCurrentJSContext()) {
ScriptSettingsStack::Push(this);
}
AutoIncumbentScript::~AutoIncumbentScript() { ScriptSettingsStack::Pop(this); }
AutoNoJSAPI::AutoNoJSAPI(JSContext* aCx)
: ScriptSettingsStackEntry(nullptr, eNoJSAPI),
JSAutoNullableRealm(aCx, nullptr),
mCx(aCx) {
// Make sure we don't seem to have an incumbent global due to
// whatever script is running right now.
JS::HideScriptedCaller(aCx);
// Make sure the fallback GetIncumbentGlobal() behavior and
// GetEntryGlobal() both return null.
ScriptSettingsStack::Push(this);
}
AutoNoJSAPI::~AutoNoJSAPI() {
ScriptSettingsStack::Pop(this);
JS::UnhideScriptedCaller(mCx);
}
} // namespace dom
AutoJSContext::AutoJSContext() : mCx(nullptr) {
JS::AutoSuppressGCAnalysis nogc;
MOZ_ASSERT(!mCx, "mCx should not be initialized!");
MOZ_ASSERT(NS_IsMainThread());
if (dom::IsJSAPIActive()) {
mCx = dom::danger::GetJSContext();
} else {
mJSAPI.Init();
mCx = mJSAPI.cx();
}
}
AutoJSContext::operator JSContext*() const { return mCx; }
AutoSafeJSContext::AutoSafeJSContext() {
MOZ_ASSERT(NS_IsMainThread());
DebugOnly<bool> ok = Init(xpc::UnprivilegedJunkScope());
MOZ_ASSERT(ok,
"This is quite odd. We should have crashed in the "
"xpc::NativeGlobal() call if xpc::UnprivilegedJunkScope() "
"returned null, and inited correctly otherwise!");
}
AutoSlowOperation::AutoSlowOperation() : mIsMainThread(NS_IsMainThread()) {
if (mIsMainThread) {
mScriptActivity.emplace(true);
}
}
void AutoSlowOperation::CheckForInterrupt() {
// For now we support only main thread!
if (mIsMainThread) {
// JS_CheckForInterrupt expects us to be in a realm, so we use a junk scope.
// In principle, it doesn't matter which one we use, since we aren't really
// running scripts here, and none of our interrupt callbacks can stop
// scripts in a junk scope anyway. In practice, though, the privileged junk
// scope is the same as the JSM global, and therefore always exists, while
// the unprivileged junk scope is created lazily, and may not exist until we
// try to use it. So we use the former for the sake of efficiency.
dom::AutoJSAPI jsapi;
MOZ_ALWAYS_TRUE(jsapi.Init(xpc::PrivilegedJunkScope()));
JS_CheckForInterrupt(jsapi.cx());
}
}
AutoAllowLegacyScriptExecution::AutoAllowLegacyScriptExecution() {
#ifdef DEBUG
// no need to do that dance if we are off the main thread,
// because we only assert if we are on the main thread!
if (!NS_IsMainThread()) {
return;
}
sAutoAllowLegacyScriptExecution++;
#endif
}
AutoAllowLegacyScriptExecution::~AutoAllowLegacyScriptExecution() {
#ifdef DEBUG
// no need to do that dance if we are off the main thread,
// because we only assert if we are on the main thread!
if (!NS_IsMainThread()) {
return;
}
sAutoAllowLegacyScriptExecution--;
MOZ_ASSERT(sAutoAllowLegacyScriptExecution >= 0,
"how can the stack guard produce a value less than 0?");
#endif
}
int AutoAllowLegacyScriptExecution::sAutoAllowLegacyScriptExecution = 0;
/*static*/
bool AutoAllowLegacyScriptExecution::IsAllowed() {
return sAutoAllowLegacyScriptExecution > 0;
}
} // namespace mozilla