summaryrefslogtreecommitdiffstats
path: root/dom/script/ScriptSettings.cpp
blob: 3b39538e51840cd9b1685b2efd2ff2e9ec83608a (plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
312
313
314
315
316
317
318
319
320
321
322
323
324
325
326
327
328
329
330
331
332
333
334
335
336
337
338
339
340
341
342
343
344
345
346
347
348
349
350
351
352
353
354
355
356
357
358
359
360
361
362
363
364
365
366
367
368
369
370
371
372
373
374
375
376
377
378
379
380
381
382
383
384
385
386
387
388
389
390
391
392
393
394
395
396
397
398
399
400
401
402
403
404
405
406
407
408
409
410
411
412
413
414
415
416
417
418
419
420
421
422
423
424
425
426
427
428
429
430
431
432
433
434
435
436
437
438
439
440
441
442
443
444
445
446
447
448
449
450
451
452
453
454
455
456
457
458
459
460
461
462
463
464
465
466
467
468
469
470
471
472
473
474
475
476
477
478
479
480
481
482
483
484
485
486
487
488
489
490
491
492
493
494
495
496
497
498
499
500
501
502
503
504
505
506
507
508
509
510
511
512
513
514
515
516
517
518
519
520
521
522
523
524
525
526
527
528
529
530
531
532
533
534
535
536
537
538
539
540
541
542
543
544
545
546
547
548
549
550
551
552
553
554
555
556
557
558
559
560
561
562
563
564
565
566
567
568
569
570
571
572
573
574
575
576
577
578
579
580
581
582
583
584
585
586
587
588
589
590
591
592
593
594
595
596
597
598
599
600
601
602
603
604
605
606
607
608
609
610
611
612
613
614
615
616
617
618
619
620
621
622
623
624
625
626
627
628
629
630
631
632
633
634
635
636
637
638
639
640
641
642
643
644
645
646
647
648
649
650
651
652
653
654
655
656
657
658
659
660
661
662
663
664
665
666
667
668
669
670
671
672
673
674
675
676
677
678
679
680
681
682
683
684
685
686
687
688
689
690
691
692
693
694
695
696
697
698
699
700
701
702
703
704
705
706
707
708
709
/* -*- 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
 * file, You can obtain one at http://mozilla.org/MPL/2.0/. */

#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