diff options
Diffstat (limited to 'js/src/vm/ErrorObject.cpp')
| -rw-r--r-- | js/src/vm/ErrorObject.cpp | 818 |
1 files changed, 818 insertions, 0 deletions
diff --git a/js/src/vm/ErrorObject.cpp b/js/src/vm/ErrorObject.cpp new file mode 100644 index 0000000000..193733d67a --- /dev/null +++ b/js/src/vm/ErrorObject.cpp @@ -0,0 +1,818 @@ +/* -*- Mode: C++; tab-width: 8; indent-tabs-mode: nil; c-basic-offset: 2 -*- + * vim: set ts=8 sw=2 et 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 "vm/ErrorObject-inl.h" + +#include "mozilla/Assertions.h" +#include "mozilla/Attributes.h" +#include "mozilla/DebugOnly.h" +#include "mozilla/Maybe.h" + +#include <utility> + +#include "jsexn.h" +#include "jspubtd.h" +#include "NamespaceImports.h" + +#include "gc/AllocKind.h" +#include "gc/GCContext.h" +#include "js/CallArgs.h" +#include "js/CallNonGenericMethod.h" +#include "js/CharacterEncoding.h" // JS::ConstUTF8CharsZ +#include "js/Class.h" +#include "js/ColumnNumber.h" // JS::ColumnNumberOneOrigin +#include "js/Conversions.h" +#include "js/ErrorReport.h" +#include "js/friend/ErrorMessages.h" // js::GetErrorMessage, JSMSG_* +#include "js/friend/StackLimits.h" // js::AutoCheckRecursionLimit +#include "js/PropertySpec.h" +#include "js/RootingAPI.h" +#include "js/Stack.h" +#include "js/TypeDecls.h" +#include "js/Utility.h" +#include "js/Value.h" +#include "js/Wrapper.h" +#include "util/StringBuffer.h" +#include "vm/GlobalObject.h" +#include "vm/Iteration.h" +#include "vm/JSAtomUtils.h" // ClassName +#include "vm/JSFunction.h" +#include "vm/JSObject.h" +#include "vm/NativeObject.h" +#include "vm/ObjectOperations.h" +#include "vm/SavedStacks.h" +#include "vm/SelfHosting.h" +#include "vm/Shape.h" +#include "vm/Stack.h" +#include "vm/StringType.h" +#include "vm/ToSource.h" // js::ValueToSource + +#include "vm/JSContext-inl.h" +#include "vm/JSObject-inl.h" +#include "vm/ObjectOperations-inl.h" +#include "vm/SavedStacks-inl.h" +#include "vm/Shape-inl.h" + +using namespace js; + +#define IMPLEMENT_ERROR_PROTO_CLASS(name) \ + { \ + #name ".prototype", JSCLASS_HAS_CACHED_PROTO(JSProto_##name), \ + JS_NULL_CLASS_OPS, \ + &ErrorObject::classSpecs[JSProto_##name - JSProto_Error] \ + } + +const JSClass ErrorObject::protoClasses[JSEXN_ERROR_LIMIT] = { + IMPLEMENT_ERROR_PROTO_CLASS(Error), + + IMPLEMENT_ERROR_PROTO_CLASS(InternalError), + IMPLEMENT_ERROR_PROTO_CLASS(AggregateError), + IMPLEMENT_ERROR_PROTO_CLASS(EvalError), + IMPLEMENT_ERROR_PROTO_CLASS(RangeError), + IMPLEMENT_ERROR_PROTO_CLASS(ReferenceError), + IMPLEMENT_ERROR_PROTO_CLASS(SyntaxError), + IMPLEMENT_ERROR_PROTO_CLASS(TypeError), + IMPLEMENT_ERROR_PROTO_CLASS(URIError), + + IMPLEMENT_ERROR_PROTO_CLASS(DebuggeeWouldRun), + IMPLEMENT_ERROR_PROTO_CLASS(CompileError), + IMPLEMENT_ERROR_PROTO_CLASS(LinkError), + IMPLEMENT_ERROR_PROTO_CLASS(RuntimeError)}; + +static bool exn_toSource(JSContext* cx, unsigned argc, Value* vp); + +static const JSFunctionSpec error_methods[] = { + JS_FN("toSource", exn_toSource, 0, 0), + JS_SELF_HOSTED_FN("toString", "ErrorToString", 0, 0), JS_FS_END}; + +// Error.prototype and NativeError.prototype have own .message and .name +// properties. +#define COMMON_ERROR_PROPERTIES(name) \ + JS_STRING_PS("message", "", 0), JS_STRING_PS("name", #name, 0) + +static const JSPropertySpec error_properties[] = { + COMMON_ERROR_PROPERTIES(Error), + // Only Error.prototype has .stack! + JS_PSGS("stack", ErrorObject::getStack, ErrorObject::setStack, 0), + JS_PS_END}; + +#define IMPLEMENT_NATIVE_ERROR_PROPERTIES(name) \ + static const JSPropertySpec name##_properties[] = { \ + COMMON_ERROR_PROPERTIES(name), JS_PS_END}; + +IMPLEMENT_NATIVE_ERROR_PROPERTIES(InternalError) +IMPLEMENT_NATIVE_ERROR_PROPERTIES(AggregateError) +IMPLEMENT_NATIVE_ERROR_PROPERTIES(EvalError) +IMPLEMENT_NATIVE_ERROR_PROPERTIES(RangeError) +IMPLEMENT_NATIVE_ERROR_PROPERTIES(ReferenceError) +IMPLEMENT_NATIVE_ERROR_PROPERTIES(SyntaxError) +IMPLEMENT_NATIVE_ERROR_PROPERTIES(TypeError) +IMPLEMENT_NATIVE_ERROR_PROPERTIES(URIError) +IMPLEMENT_NATIVE_ERROR_PROPERTIES(DebuggeeWouldRun) +IMPLEMENT_NATIVE_ERROR_PROPERTIES(CompileError) +IMPLEMENT_NATIVE_ERROR_PROPERTIES(LinkError) +IMPLEMENT_NATIVE_ERROR_PROPERTIES(RuntimeError) + +#define IMPLEMENT_NATIVE_ERROR_SPEC(name) \ + { \ + ErrorObject::createConstructor, ErrorObject::createProto, nullptr, \ + nullptr, nullptr, name##_properties, nullptr, JSProto_Error \ + } + +#define IMPLEMENT_NONGLOBAL_ERROR_SPEC(name) \ + { \ + ErrorObject::createConstructor, ErrorObject::createProto, nullptr, \ + nullptr, nullptr, name##_properties, nullptr, \ + JSProto_Error | ClassSpec::DontDefineConstructor \ + } + +const ClassSpec ErrorObject::classSpecs[JSEXN_ERROR_LIMIT] = { + {ErrorObject::createConstructor, ErrorObject::createProto, nullptr, nullptr, + error_methods, error_properties}, + + IMPLEMENT_NATIVE_ERROR_SPEC(InternalError), + IMPLEMENT_NATIVE_ERROR_SPEC(AggregateError), + IMPLEMENT_NATIVE_ERROR_SPEC(EvalError), + IMPLEMENT_NATIVE_ERROR_SPEC(RangeError), + IMPLEMENT_NATIVE_ERROR_SPEC(ReferenceError), + IMPLEMENT_NATIVE_ERROR_SPEC(SyntaxError), + IMPLEMENT_NATIVE_ERROR_SPEC(TypeError), + IMPLEMENT_NATIVE_ERROR_SPEC(URIError), + + IMPLEMENT_NONGLOBAL_ERROR_SPEC(DebuggeeWouldRun), + IMPLEMENT_NONGLOBAL_ERROR_SPEC(CompileError), + IMPLEMENT_NONGLOBAL_ERROR_SPEC(LinkError), + IMPLEMENT_NONGLOBAL_ERROR_SPEC(RuntimeError)}; + +#define IMPLEMENT_ERROR_CLASS_CORE(name, reserved_slots) \ + { \ + #name, \ + JSCLASS_HAS_CACHED_PROTO(JSProto_##name) | \ + JSCLASS_HAS_RESERVED_SLOTS(reserved_slots) | \ + JSCLASS_BACKGROUND_FINALIZE, \ + &ErrorObjectClassOps, \ + &ErrorObject::classSpecs[JSProto_##name - JSProto_Error] \ + } + +#define IMPLEMENT_ERROR_CLASS(name) \ + IMPLEMENT_ERROR_CLASS_CORE(name, ErrorObject::RESERVED_SLOTS) + +// Only used for classes that could be a Wasm trap. Classes that use this +// macro should be kept in sync with the exception types that mightBeWasmTrap() +// will return true for. +#define IMPLEMENT_ERROR_CLASS_MAYBE_WASM_TRAP(name) \ + IMPLEMENT_ERROR_CLASS_CORE(name, ErrorObject::RESERVED_SLOTS_MAYBE_WASM_TRAP) + +static void exn_finalize(JS::GCContext* gcx, JSObject* obj); + +static const JSClassOps ErrorObjectClassOps = { + nullptr, // addProperty + nullptr, // delProperty + nullptr, // enumerate + nullptr, // newEnumerate + nullptr, // resolve + nullptr, // mayResolve + exn_finalize, // finalize + nullptr, // call + nullptr, // construct + nullptr, // trace +}; + +const JSClass ErrorObject::classes[JSEXN_ERROR_LIMIT] = { + IMPLEMENT_ERROR_CLASS(Error), + IMPLEMENT_ERROR_CLASS_MAYBE_WASM_TRAP(InternalError), + IMPLEMENT_ERROR_CLASS(AggregateError), IMPLEMENT_ERROR_CLASS(EvalError), + IMPLEMENT_ERROR_CLASS(RangeError), IMPLEMENT_ERROR_CLASS(ReferenceError), + IMPLEMENT_ERROR_CLASS(SyntaxError), IMPLEMENT_ERROR_CLASS(TypeError), + IMPLEMENT_ERROR_CLASS(URIError), + // These Error subclasses are not accessible via the global object: + IMPLEMENT_ERROR_CLASS(DebuggeeWouldRun), + IMPLEMENT_ERROR_CLASS(CompileError), IMPLEMENT_ERROR_CLASS(LinkError), + IMPLEMENT_ERROR_CLASS_MAYBE_WASM_TRAP(RuntimeError)}; + +static void exn_finalize(JS::GCContext* gcx, JSObject* obj) { + if (JSErrorReport* report = obj->as<ErrorObject>().getErrorReport()) { + // Bug 1560019: This allocation is not currently tracked. + gcx->deleteUntracked(report); + } +} + +static ErrorObject* CreateErrorObject(JSContext* cx, const CallArgs& args, + unsigned messageArg, JSExnType exnType, + HandleObject proto) { + // Compute the error message, if any. + RootedString message(cx, nullptr); + if (args.hasDefined(messageArg)) { + message = ToString<CanGC>(cx, args[messageArg]); + if (!message) { + return nullptr; + } + } + + // Don't interpret the two parameters following the message parameter as the + // non-standard fileName and lineNumber arguments when we have an options + // object argument. + bool hasOptions = args.get(messageArg + 1).isObject(); + + Rooted<mozilla::Maybe<Value>> cause(cx, mozilla::Nothing()); + if (hasOptions) { + RootedObject options(cx, &args[messageArg + 1].toObject()); + + bool hasCause = false; + if (!HasProperty(cx, options, cx->names().cause, &hasCause)) { + return nullptr; + } + + if (hasCause) { + RootedValue causeValue(cx); + if (!GetProperty(cx, options, options, cx->names().cause, &causeValue)) { + return nullptr; + } + cause = mozilla::Some(causeValue.get()); + } + } + + // Find the scripted caller, but only ones we're allowed to know about. + NonBuiltinFrameIter iter(cx, cx->realm()->principals()); + + RootedString fileName(cx); + uint32_t sourceId = 0; + if (!hasOptions && args.length() > messageArg + 1) { + fileName = ToString<CanGC>(cx, args[messageArg + 1]); + } else { + fileName = cx->runtime()->emptyString; + if (!iter.done()) { + if (const char* cfilename = iter.filename()) { + fileName = JS_NewStringCopyUTF8Z( + cx, JS::ConstUTF8CharsZ(cfilename, strlen(cfilename))); + } + if (iter.hasScript()) { + sourceId = iter.script()->scriptSource()->id(); + } + } + } + if (!fileName) { + return nullptr; + } + + uint32_t lineNumber; + JS::ColumnNumberOneOrigin columnNumber; + if (!hasOptions && args.length() > messageArg + 2) { + if (!ToUint32(cx, args[messageArg + 2], &lineNumber)) { + return nullptr; + } + } else { + JS::TaggedColumnNumberOneOrigin tmp; + lineNumber = iter.done() ? 0 : iter.computeLine(&tmp); + columnNumber = JS::ColumnNumberOneOrigin(tmp.oneOriginValue()); + } + + RootedObject stack(cx); + if (!CaptureStack(cx, &stack)) { + return nullptr; + } + + return ErrorObject::create(cx, exnType, stack, fileName, sourceId, lineNumber, + columnNumber, nullptr, message, cause, proto); +} + +static bool Error(JSContext* cx, unsigned argc, Value* vp) { + CallArgs args = CallArgsFromVp(argc, vp); + + // ECMA ed. 3, 15.11.1 requires Error, etc., to construct even when + // called as functions, without operator new. But as we do not give + // each constructor a distinct JSClass, we must get the exception type + // ourselves. + JSExnType exnType = + JSExnType(args.callee().as<JSFunction>().getExtendedSlot(0).toInt32()); + + MOZ_ASSERT(exnType != JSEXN_AGGREGATEERR, + "AggregateError has its own constructor function"); + + JSProtoKey protoKey = + JSCLASS_CACHED_PROTO_KEY(&ErrorObject::classes[exnType]); + + // ES6 19.5.1.1 mandates the .prototype lookup happens before the toString + RootedObject proto(cx); + if (!GetPrototypeFromBuiltinConstructor(cx, args, protoKey, &proto)) { + return false; + } + + auto* obj = CreateErrorObject(cx, args, 0, exnType, proto); + if (!obj) { + return false; + } + + args.rval().setObject(*obj); + return true; +} + +// AggregateError ( errors, message ) +static bool AggregateError(JSContext* cx, unsigned argc, Value* vp) { + CallArgs args = CallArgsFromVp(argc, vp); + + mozilla::DebugOnly<JSExnType> exnType = + JSExnType(args.callee().as<JSFunction>().getExtendedSlot(0).toInt32()); + + MOZ_ASSERT(exnType == JSEXN_AGGREGATEERR); + + // Steps 1-2. (9.1.13 OrdinaryCreateFromConstructor, steps 1-2). + RootedObject proto(cx); + if (!GetPrototypeFromBuiltinConstructor(cx, args, JSProto_AggregateError, + &proto)) { + return false; + } + + // TypeError anyway, but this gives a better error message. + if (!args.requireAtLeast(cx, "AggregateError", 1)) { + return false; + } + + // 9.1.13 OrdinaryCreateFromConstructor, step 3. + // Step 3. + Rooted<ErrorObject*> obj( + cx, CreateErrorObject(cx, args, 1, JSEXN_AGGREGATEERR, proto)); + if (!obj) { + return false; + } + + // Step 4. + + Rooted<ArrayObject*> errorsList(cx); + if (!IterableToArray(cx, args.get(0), &errorsList)) { + return false; + } + + // Step 5. + RootedValue errorsVal(cx, JS::ObjectValue(*errorsList)); + if (!NativeDefineDataProperty(cx, obj, cx->names().errors, errorsVal, 0)) { + return false; + } + + // Step 6. + args.rval().setObject(*obj); + return true; +} + +/* static */ +JSObject* ErrorObject::createProto(JSContext* cx, JSProtoKey key) { + JSExnType type = ExnTypeFromProtoKey(key); + + if (type == JSEXN_ERR) { + return GlobalObject::createBlankPrototype( + cx, cx->global(), &ErrorObject::protoClasses[JSEXN_ERR]); + } + + RootedObject protoProto( + cx, GlobalObject::getOrCreateErrorPrototype(cx, cx->global())); + if (!protoProto) { + return nullptr; + } + + return GlobalObject::createBlankPrototypeInheriting( + cx, &ErrorObject::protoClasses[type], protoProto); +} + +/* static */ +JSObject* ErrorObject::createConstructor(JSContext* cx, JSProtoKey key) { + JSExnType type = ExnTypeFromProtoKey(key); + RootedObject ctor(cx); + + if (type == JSEXN_ERR) { + ctor = GenericCreateConstructor<Error, 1, gc::AllocKind::FUNCTION_EXTENDED>( + cx, key); + } else { + RootedFunction proto( + cx, GlobalObject::getOrCreateErrorConstructor(cx, cx->global())); + if (!proto) { + return nullptr; + } + + Native native; + unsigned nargs; + if (type == JSEXN_AGGREGATEERR) { + native = AggregateError; + nargs = 2; + } else { + native = Error; + nargs = 1; + } + + ctor = + NewFunctionWithProto(cx, native, nargs, FunctionFlags::NATIVE_CTOR, + nullptr, ClassName(key, cx), proto, + gc::AllocKind::FUNCTION_EXTENDED, TenuredObject); + } + + if (!ctor) { + return nullptr; + } + + ctor->as<JSFunction>().setExtendedSlot(0, Int32Value(type)); + return ctor; +} + +/* static */ +SharedShape* js::ErrorObject::assignInitialShape(JSContext* cx, + Handle<ErrorObject*> obj) { + MOZ_ASSERT(obj->empty()); + + constexpr PropertyFlags propFlags = {PropertyFlag::Configurable, + PropertyFlag::Writable}; + + if (!NativeObject::addPropertyInReservedSlot(cx, obj, cx->names().fileName, + FILENAME_SLOT, propFlags)) { + return nullptr; + } + + if (!NativeObject::addPropertyInReservedSlot(cx, obj, cx->names().lineNumber, + LINENUMBER_SLOT, propFlags)) { + return nullptr; + } + + if (!NativeObject::addPropertyInReservedSlot( + cx, obj, cx->names().columnNumber, COLUMNNUMBER_SLOT, propFlags)) { + return nullptr; + } + + return obj->sharedShape(); +} + +/* static */ +bool js::ErrorObject::init(JSContext* cx, Handle<ErrorObject*> obj, + JSExnType type, UniquePtr<JSErrorReport> errorReport, + HandleString fileName, HandleObject stack, + uint32_t sourceId, uint32_t lineNumber, + JS::ColumnNumberOneOrigin columnNumber, + HandleString message, + Handle<mozilla::Maybe<JS::Value>> cause) { + MOZ_ASSERT(JSEXN_ERR <= type && type < JSEXN_ERROR_LIMIT); + AssertObjectIsSavedFrameOrWrapper(cx, stack); + cx->check(obj, stack); + + // Null out early in case of error, for exn_finalize's sake. + obj->initReservedSlot(ERROR_REPORT_SLOT, PrivateValue(nullptr)); + + if (!SharedShape::ensureInitialCustomShape<ErrorObject>(cx, obj)) { + return false; + } + + // The .message property isn't part of the initial shape because it's + // present in some error objects -- |Error.prototype|, |new Error("f")|, + // |new Error("")| -- but not in others -- |new Error(undefined)|, + // |new Error()|. + if (message) { + constexpr PropertyFlags propFlags = {PropertyFlag::Configurable, + PropertyFlag::Writable}; + if (!NativeObject::addPropertyInReservedSlot(cx, obj, cx->names().message, + MESSAGE_SLOT, propFlags)) { + return false; + } + } + + // Similar to the .message property, .cause is present only in some error + // objects -- |new Error("f", {cause: cause})| -- but not in other -- + // |Error.prototype|, |new Error()|, |new Error("f")|. + if (cause.isSome()) { + constexpr PropertyFlags propFlags = {PropertyFlag::Configurable, + PropertyFlag::Writable}; + if (!NativeObject::addPropertyInReservedSlot(cx, obj, cx->names().cause, + CAUSE_SLOT, propFlags)) { + return false; + } + } + + MOZ_ASSERT(obj->lookupPure(NameToId(cx->names().fileName))->slot() == + FILENAME_SLOT); + MOZ_ASSERT(obj->lookupPure(NameToId(cx->names().lineNumber))->slot() == + LINENUMBER_SLOT); + MOZ_ASSERT(obj->lookupPure(NameToId(cx->names().columnNumber))->slot() == + COLUMNNUMBER_SLOT); + MOZ_ASSERT_IF( + message, + obj->lookupPure(NameToId(cx->names().message))->slot() == MESSAGE_SLOT); + MOZ_ASSERT_IF( + cause.isSome(), + obj->lookupPure(NameToId(cx->names().cause))->slot() == CAUSE_SLOT); + + JSErrorReport* report = errorReport.release(); + obj->initReservedSlot(STACK_SLOT, ObjectOrNullValue(stack)); + obj->setReservedSlot(ERROR_REPORT_SLOT, PrivateValue(report)); + obj->initReservedSlot(FILENAME_SLOT, StringValue(fileName)); + obj->initReservedSlot(LINENUMBER_SLOT, Int32Value(lineNumber)); + obj->initReservedSlot(COLUMNNUMBER_SLOT, + Int32Value(columnNumber.oneOriginValue())); + if (message) { + obj->initReservedSlot(MESSAGE_SLOT, StringValue(message)); + } + if (cause.isSome()) { + obj->initReservedSlot(CAUSE_SLOT, *cause.get()); + } else { + obj->initReservedSlot(CAUSE_SLOT, MagicValue(JS_ERROR_WITHOUT_CAUSE)); + } + obj->initReservedSlot(SOURCEID_SLOT, Int32Value(sourceId)); + if (obj->mightBeWasmTrap()) { + MOZ_ASSERT(JSCLASS_RESERVED_SLOTS(obj->getClass()) > WASM_TRAP_SLOT); + obj->initReservedSlot(WASM_TRAP_SLOT, BooleanValue(false)); + } + + return true; +} + +/* static */ +ErrorObject* js::ErrorObject::create(JSContext* cx, JSExnType errorType, + HandleObject stack, HandleString fileName, + uint32_t sourceId, uint32_t lineNumber, + JS::ColumnNumberOneOrigin columnNumber, + UniquePtr<JSErrorReport> report, + HandleString message, + Handle<mozilla::Maybe<JS::Value>> cause, + HandleObject protoArg /* = nullptr */) { + AssertObjectIsSavedFrameOrWrapper(cx, stack); + + RootedObject proto(cx, protoArg); + if (!proto) { + proto = GlobalObject::getOrCreateCustomErrorPrototype(cx, cx->global(), + errorType); + if (!proto) { + return nullptr; + } + } + + Rooted<ErrorObject*> errObject(cx); + { + const JSClass* clasp = ErrorObject::classForType(errorType); + JSObject* obj = NewObjectWithGivenProto(cx, clasp, proto); + if (!obj) { + return nullptr; + } + errObject = &obj->as<ErrorObject>(); + } + + if (!ErrorObject::init(cx, errObject, errorType, std::move(report), fileName, + stack, sourceId, lineNumber, columnNumber, message, + cause)) { + return nullptr; + } + + return errObject; +} + +JSErrorReport* js::ErrorObject::getOrCreateErrorReport(JSContext* cx) { + if (JSErrorReport* r = getErrorReport()) { + return r; + } + + // We build an error report on the stack and then use CopyErrorReport to do + // the nitty-gritty malloc stuff. + JSErrorReport report; + + // Type. + JSExnType type_ = type(); + report.exnType = type_; + + // Filename. + RootedString filename(cx, fileName(cx)); + UniqueChars filenameStr = JS_EncodeStringToUTF8(cx, filename); + if (!filenameStr) { + return nullptr; + } + report.filename = JS::ConstUTF8CharsZ(filenameStr.get()); + + // Coordinates. + report.sourceId = sourceId(); + report.lineno = lineNumber(); + report.column = columnNumber(); + + // Message. Note that |new Error()| will result in an undefined |message| + // slot, so we need to explicitly substitute the empty string in that case. + RootedString message(cx, getMessage()); + if (!message) { + message = cx->runtime()->emptyString; + } + + UniqueChars utf8 = StringToNewUTF8CharsZ(cx, *message); + if (!utf8) { + return nullptr; + } + report.initOwnedMessage(utf8.release()); + + // Cache and return. + UniquePtr<JSErrorReport> copy = CopyErrorReport(cx, &report); + if (!copy) { + return nullptr; + } + setReservedSlot(ERROR_REPORT_SLOT, PrivateValue(copy.get())); + return copy.release(); +} + +static bool FindErrorInstanceOrPrototype(JSContext* cx, HandleObject obj, + MutableHandleObject result) { + // Walk up the prototype chain until we find an error object instance or + // prototype object. This allows code like: + // Object.create(Error.prototype).stack + // or + // function NYI() { } + // NYI.prototype = new Error; + // (new NYI).stack + // to continue returning stacks that are useless, but at least don't throw. + + RootedObject curr(cx, obj); + RootedObject target(cx); + do { + target = CheckedUnwrapStatic(curr); + if (!target) { + ReportAccessDenied(cx); + return false; + } + if (IsErrorProtoKey(StandardProtoKeyOrNull(target))) { + result.set(target); + return true; + } + + if (!GetPrototype(cx, curr, &curr)) { + return false; + } + } while (curr); + + // We walked the whole prototype chain and did not find an Error + // object. + JS_ReportErrorNumberASCII(cx, GetErrorMessage, nullptr, + JSMSG_INCOMPATIBLE_PROTO, "Error", "(get stack)", + obj->getClass()->name); + return false; +} + +static MOZ_ALWAYS_INLINE bool IsObject(HandleValue v) { return v.isObject(); } + +/* static */ +bool js::ErrorObject::getStack(JSContext* cx, unsigned argc, Value* vp) { + CallArgs args = CallArgsFromVp(argc, vp); + // We accept any object here, because of poor-man's subclassing of Error. + return CallNonGenericMethod<IsObject, getStack_impl>(cx, args); +} + +/* static */ +bool js::ErrorObject::getStack_impl(JSContext* cx, const CallArgs& args) { + RootedObject thisObj(cx, &args.thisv().toObject()); + + RootedObject obj(cx); + if (!FindErrorInstanceOrPrototype(cx, thisObj, &obj)) { + return false; + } + + if (!obj->is<ErrorObject>()) { + args.rval().setString(cx->runtime()->emptyString); + return true; + } + + // Do frame filtering based on the ErrorObject's principals. This ensures we + // don't see chrome frames when chrome code accesses .stack over Xrays. + JSPrincipals* principals = obj->as<ErrorObject>().realm()->principals(); + + RootedObject savedFrameObj(cx, obj->as<ErrorObject>().stack()); + RootedString stackString(cx); + if (!BuildStackString(cx, principals, savedFrameObj, &stackString)) { + return false; + } + + if (cx->runtime()->stackFormat() == js::StackFormat::V8) { + // When emulating V8 stack frames, we also need to prepend the + // stringified Error to the stack string. + Handle<PropertyName*> name = cx->names().ErrorToStringWithTrailingNewline; + FixedInvokeArgs<0> args2(cx); + RootedValue rval(cx); + if (!CallSelfHostedFunction(cx, name, args.thisv(), args2, &rval)) { + return false; + } + + if (!rval.isString()) { + args.rval().setString(cx->runtime()->emptyString); + return true; + } + + RootedString stringified(cx, rval.toString()); + stackString = ConcatStrings<CanGC>(cx, stringified, stackString); + } + + args.rval().setString(stackString); + return true; +} + +/* static */ +bool js::ErrorObject::setStack(JSContext* cx, unsigned argc, Value* vp) { + CallArgs args = CallArgsFromVp(argc, vp); + // We accept any object here, because of poor-man's subclassing of Error. + return CallNonGenericMethod<IsObject, setStack_impl>(cx, args); +} + +/* static */ +bool js::ErrorObject::setStack_impl(JSContext* cx, const CallArgs& args) { + RootedObject thisObj(cx, &args.thisv().toObject()); + + if (!args.requireAtLeast(cx, "(set stack)", 1)) { + return false; + } + RootedValue val(cx, args[0]); + + return DefineDataProperty(cx, thisObj, cx->names().stack, val); +} + +void js::ErrorObject::setFromWasmTrap() { + MOZ_ASSERT(mightBeWasmTrap()); + MOZ_ASSERT(JSCLASS_RESERVED_SLOTS(getClass()) > WASM_TRAP_SLOT); + setReservedSlot(WASM_TRAP_SLOT, BooleanValue(true)); +} + +JSString* js::ErrorToSource(JSContext* cx, HandleObject obj) { + RootedValue nameVal(cx); + RootedString name(cx); + if (!GetProperty(cx, obj, obj, cx->names().name, &nameVal) || + !(name = ToString<CanGC>(cx, nameVal))) { + return nullptr; + } + + RootedValue messageVal(cx); + RootedString message(cx); + if (!GetProperty(cx, obj, obj, cx->names().message, &messageVal) || + !(message = ValueToSource(cx, messageVal))) { + return nullptr; + } + + RootedValue filenameVal(cx); + RootedString filename(cx); + if (!GetProperty(cx, obj, obj, cx->names().fileName, &filenameVal) || + !(filename = ValueToSource(cx, filenameVal))) { + return nullptr; + } + + RootedValue linenoVal(cx); + uint32_t lineno; + if (!GetProperty(cx, obj, obj, cx->names().lineNumber, &linenoVal) || + !ToUint32(cx, linenoVal, &lineno)) { + return nullptr; + } + + JSStringBuilder sb(cx); + if (!sb.append("(new ") || !sb.append(name) || !sb.append("(")) { + return nullptr; + } + + if (!sb.append(message)) { + return nullptr; + } + + if (!filename->empty()) { + if (!sb.append(", ") || !sb.append(filename)) { + return nullptr; + } + } + if (lineno != 0) { + /* We have a line, but no filename, add empty string */ + if (filename->empty() && !sb.append(", \"\"")) { + return nullptr; + } + + JSString* linenumber = ToString<CanGC>(cx, linenoVal); + if (!linenumber) { + return nullptr; + } + if (!sb.append(", ") || !sb.append(linenumber)) { + return nullptr; + } + } + + if (!sb.append("))")) { + return nullptr; + } + + return sb.finishString(); +} + +/* + * Return a string that may eval to something similar to the original object. + */ +static bool exn_toSource(JSContext* cx, unsigned argc, Value* vp) { + AutoCheckRecursionLimit recursion(cx); + if (!recursion.check(cx)) { + return false; + } + CallArgs args = CallArgsFromVp(argc, vp); + + RootedObject obj(cx, ToObject(cx, args.thisv())); + if (!obj) { + return false; + } + + JSString* str = ErrorToSource(cx, obj); + if (!str) { + return false; + } + + args.rval().setString(str); + return true; +} |