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Mypal/js/src/jsexn.cpp

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/* -*- Mode: C++; tab-width: 8; indent-tabs-mode: nil; c-basic-offset: 4 -*-
* vim: set ts=8 sts=4 et sw=4 tw=99:
* 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/. */
/*
* JS standard exception implementation.
*/
#include "jsexn.h"
#include "mozilla/ArrayUtils.h"
#include "mozilla/PodOperations.h"
#include "mozilla/Sprintf.h"
#include <string.h>
#include "jsapi.h"
#include "jscntxt.h"
#include "jsfun.h"
#include "jsnum.h"
#include "jsobj.h"
#include "jsprf.h"
#include "jsscript.h"
#include "jstypes.h"
#include "jsutil.h"
#include "jswrapper.h"
#include "gc/Marking.h"
#include "js/CharacterEncoding.h"
#include "vm/ErrorObject.h"
#include "vm/GlobalObject.h"
#include "vm/SavedStacks.h"
#include "vm/StringBuffer.h"
#include "jsobjinlines.h"
#include "vm/ErrorObject-inl.h"
#include "vm/SavedStacks-inl.h"
using namespace js;
using namespace js::gc;
using mozilla::ArrayLength;
using mozilla::PodArrayZero;
static void
exn_finalize(FreeOp* fop, JSObject* obj);
static bool
exn_toSource(JSContext* cx, unsigned argc, Value* vp);
#define IMPLEMENT_ERROR_PROTO_CLASS(name) \
{ \
js_Object_str, \
JSCLASS_HAS_CACHED_PROTO(JSProto_##name), \
JS_NULL_CLASS_OPS, \
&ErrorObject::classSpecs[JSProto_##name - JSProto_Error] \
}
const Class
ErrorObject::protoClasses[JSEXN_ERROR_LIMIT] = {
IMPLEMENT_ERROR_PROTO_CLASS(Error),
IMPLEMENT_ERROR_PROTO_CLASS(InternalError),
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(RuntimeError)
};
static const JSFunctionSpec error_methods[] = {
#if JS_HAS_TOSOURCE
JS_FN(js_toSource_str, exn_toSource, 0, 0),
#endif
JS_SELF_HOSTED_FN(js_toString_str, "ErrorToString", 0,0),
JS_FS_END
};
static const JSPropertySpec error_properties[] = {
JS_STRING_PS("message", "", 0),
JS_STRING_PS("name", "Error", 0),
// Only Error.prototype has .stack!
JS_PSGS("stack", ErrorObject::getStack, ErrorObject::setStack, 0),
JS_PS_END
};
#define IMPLEMENT_ERROR_PROPERTIES(name) \
{ \
JS_STRING_PS("message", "", 0), \
JS_STRING_PS("name", #name, 0), \
JS_PS_END \
}
static const JSPropertySpec other_error_properties[JSEXN_ERROR_LIMIT - 1][3] = {
IMPLEMENT_ERROR_PROPERTIES(InternalError),
IMPLEMENT_ERROR_PROPERTIES(EvalError),
IMPLEMENT_ERROR_PROPERTIES(RangeError),
IMPLEMENT_ERROR_PROPERTIES(ReferenceError),
IMPLEMENT_ERROR_PROPERTIES(SyntaxError),
IMPLEMENT_ERROR_PROPERTIES(TypeError),
IMPLEMENT_ERROR_PROPERTIES(URIError),
IMPLEMENT_ERROR_PROPERTIES(DebuggeeWouldRun),
IMPLEMENT_ERROR_PROPERTIES(CompileError),
IMPLEMENT_ERROR_PROPERTIES(RuntimeError)
};
#define IMPLEMENT_NATIVE_ERROR_SPEC(name) \
{ \
ErrorObject::createConstructor, \
ErrorObject::createProto, \
nullptr, \
nullptr, \
nullptr, \
other_error_properties[JSProto_##name - JSProto_Error - 1], \
nullptr, \
JSProto_Error \
}
#define IMPLEMENT_NONGLOBAL_ERROR_SPEC(name) \
{ \
ErrorObject::createConstructor, \
ErrorObject::createProto, \
nullptr, \
nullptr, \
nullptr, \
other_error_properties[JSProto_##name - JSProto_Error - 1], \
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(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(RuntimeError)
};
#define IMPLEMENT_ERROR_CLASS(name) \
{ \
js_Error_str, /* yes, really */ \
JSCLASS_HAS_CACHED_PROTO(JSProto_##name) | \
JSCLASS_HAS_RESERVED_SLOTS(ErrorObject::RESERVED_SLOTS) | \
JSCLASS_BACKGROUND_FINALIZE, \
&ErrorObjectClassOps, \
&ErrorObject::classSpecs[JSProto_##name - JSProto_Error ] \
}
static const ClassOps ErrorObjectClassOps = {
nullptr, /* addProperty */
nullptr, /* delProperty */
nullptr, /* getProperty */
nullptr, /* setProperty */
nullptr, /* enumerate */
nullptr, /* resolve */
nullptr, /* mayResolve */
exn_finalize,
nullptr, /* call */
nullptr, /* hasInstance */
nullptr, /* construct */
nullptr, /* trace */
};
const Class
ErrorObject::classes[JSEXN_ERROR_LIMIT] = {
IMPLEMENT_ERROR_CLASS(Error),
IMPLEMENT_ERROR_CLASS(InternalError),
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(RuntimeError)
};
size_t
ExtraMallocSize(JSErrorReport* report)
{
if (report->linebuf())
/*
* Mozilla bug 1352449. Count with null
* terminator and alignment. See CopyExtraData for
* the details about alignment.
*/
return (report->linebufLength() + 1) * sizeof(char16_t) + 1;
return 0;
}
size_t
ExtraMallocSize(JSErrorNotes::Note* note)
{
return 0;
}
bool
CopyExtraData(JSContext* cx, uint8_t** cursor, JSErrorReport* copy, JSErrorReport* report)
{
if (report->linebuf()) {
/*
* Make sure cursor is properly aligned for char16_t for platforms
* which need it and it's at the end of the buffer on exit.
*/
size_t alignment_backlog = 0;
if (size_t(*cursor) % 2)
(*cursor)++;
else
alignment_backlog = 1;
size_t linebufSize = (report->linebufLength() + 1) * sizeof(char16_t);
const char16_t* linebufCopy = (const char16_t*)(*cursor);
js_memcpy(*cursor, report->linebuf(), linebufSize);
*cursor += linebufSize + alignment_backlog;
copy->initBorrowedLinebuf(linebufCopy, report->linebufLength(), report->tokenOffset());
}
/* Copy non-pointer members. */
copy->isMuted = report->isMuted;
copy->exnType = report->exnType;
/* Note that this is before it gets flagged with JSREPORT_EXCEPTION */
copy->flags = report->flags;
/* Deep copy notes. */
if (report->notes) {
auto copiedNotes = report->notes->copy(cx);
if (!copiedNotes)
return false;
copy->notes = Move(copiedNotes);
} else {
copy->notes.reset(nullptr);
}
return true;
}
bool
CopyExtraData(JSContext* cx, uint8_t** cursor, JSErrorNotes::Note* copy, JSErrorNotes::Note* report)
{
return true;
}
template <typename T>
static T*
CopyErrorHelper(JSContext* cx, T* report)
{
/*
* We use a single malloc block to make a deep copy of JSErrorReport or
* JSErrorNotes::Note, except JSErrorNotes linked from JSErrorReport with
* the following layout:
* JSErrorReport or JSErrorNotes::Note
* char array with characters for message_
* char array with characters for filename
* char16_t array with characters for linebuf (only for JSErrorReport)
* Such layout together with the properties enforced by the following
* asserts does not need any extra alignment padding.
*/
JS_STATIC_ASSERT(sizeof(T) % sizeof(const char*) == 0);
JS_STATIC_ASSERT(sizeof(const char*) % sizeof(char16_t) == 0);
size_t filenameSize = report->filename ? strlen(report->filename) + 1 : 0;
size_t messageSize = 0;
if (report->message())
messageSize = strlen(report->message().c_str()) + 1;
/*
* The mallocSize can not overflow since it represents the sum of the
* sizes of already allocated objects.
*/
size_t mallocSize = sizeof(T) + messageSize + filenameSize + ExtraMallocSize(report);
uint8_t* cursor = cx->pod_calloc<uint8_t>(mallocSize);
if (!cursor)
return nullptr;
T* copy = new (cursor) T();
cursor += sizeof(T);
if (report->message()) {
copy->initBorrowedMessage((const char*)cursor);
js_memcpy(cursor, report->message().c_str(), messageSize);
cursor += messageSize;
}
if (report->filename) {
copy->filename = (const char*)cursor;
js_memcpy(cursor, report->filename, filenameSize);
cursor += filenameSize;
}
if (!CopyExtraData(cx, &cursor, copy, report)) {
/* js_delete calls destructor for T and js_free for pod_calloc. */
js_delete(copy);
return nullptr;
}
MOZ_ASSERT(cursor == (uint8_t*)copy + mallocSize);
/* Copy non-pointer members. */
copy->lineno = report->lineno;
copy->column = report->column;
copy->errorNumber = report->errorNumber;
return copy;
}
JSErrorNotes::Note*
js::CopyErrorNote(JSContext* cx, JSErrorNotes::Note* note)
{
return CopyErrorHelper(cx, note);
}
JSErrorReport*
js::CopyErrorReport(JSContext* cx, JSErrorReport* report)
{
return CopyErrorHelper(cx, report);
}
struct SuppressErrorsGuard
{
JSContext* cx;
JS::WarningReporter prevReporter;
JS::AutoSaveExceptionState prevState;
explicit SuppressErrorsGuard(JSContext* cx)
: cx(cx),
prevReporter(JS::SetWarningReporter(cx, nullptr)),
prevState(cx)
{}
~SuppressErrorsGuard()
{
JS::SetWarningReporter(cx, prevReporter);
}
};
// Cut off the stack if it gets too deep (most commonly for infinite recursion
// errors).
static const size_t MAX_REPORTED_STACK_DEPTH = 1u << 7;
static bool
CaptureStack(JSContext* cx, MutableHandleObject stack)
{
return CaptureCurrentStack(cx, stack,
JS::StackCapture(JS::MaxFrames(MAX_REPORTED_STACK_DEPTH)));
}
JSString*
js::ComputeStackString(JSContext* cx)
{
SuppressErrorsGuard seg(cx);
RootedObject stack(cx);
if (!CaptureStack(cx, &stack))
return nullptr;
RootedString str(cx);
if (!BuildStackString(cx, stack, &str))
return nullptr;
return str.get();
}
static void
exn_finalize(FreeOp* fop, JSObject* obj)
{
MOZ_ASSERT(fop->maybeOffMainThread());
if (JSErrorReport* report = obj->as<ErrorObject>().getErrorReport())
fop->delete_(report);
}
JSErrorReport*
js::ErrorFromException(JSContext* cx, HandleObject objArg)
{
// It's ok to UncheckedUnwrap here, since all we do is get the
// JSErrorReport, and consumers are careful with the information they get
// from that anyway. Anyone doing things that would expose anything in the
// JSErrorReport to page script either does a security check on the
// JSErrorReport's principal or also tries to do toString on our object and
// will fail if they can't unwrap it.
RootedObject obj(cx, UncheckedUnwrap(objArg));
if (!obj->is<ErrorObject>())
return nullptr;
JSErrorReport* report = obj->as<ErrorObject>().getOrCreateErrorReport(cx);
if (!report) {
MOZ_ASSERT(cx->isThrowingOutOfMemory());
cx->recoverFromOutOfMemory();
}
return report;
}
JS_PUBLIC_API(JSObject*)
ExceptionStackOrNull(HandleObject objArg)
{
JSObject* obj = CheckedUnwrap(objArg);
if (!obj || !obj->is<ErrorObject>()) {
return nullptr;
}
return obj->as<ErrorObject>().stack();
}
bool
Error(JSContext* cx, unsigned argc, Value* vp)
{
CallArgs args = CallArgsFromVp(argc, vp);
// ES6 19.5.1.1 mandates the .prototype lookup happens before the toString
RootedObject proto(cx);
if (!GetPrototypeFromCallableConstructor(cx, args, &proto))
return false;
/* Compute the error message, if any. */
RootedString message(cx, nullptr);
if (args.hasDefined(0)) {
message = ToString<CanGC>(cx, args[0]);
if (!message)
return false;
}
/* Find the scripted caller, but only ones we're allowed to know about. */
NonBuiltinFrameIter iter(cx, cx->compartment()->principals());
/* Set the 'fileName' property. */
RootedString fileName(cx);
if (args.length() > 1) {
fileName = ToString<CanGC>(cx, args[1]);
} else {
fileName = cx->runtime()->emptyString;
if (!iter.done()) {
if (const char* cfilename = iter.filename())
fileName = JS_NewStringCopyZ(cx, cfilename);
}
}
if (!fileName)
return false;
/* Set the 'lineNumber' property. */
uint32_t lineNumber, columnNumber = 0;
if (args.length() > 2) {
if (!ToUint32(cx, args[2], &lineNumber))
return false;
} else {
lineNumber = iter.done() ? 0 : iter.computeLine(&columnNumber);
// XXX: Make the column 1-based as in other browsers, instead of 0-based
// which is how SpiderMonkey stores it internally. This will be
// unnecessary once bug 1144340 is fixed.
++columnNumber;
}
RootedObject stack(cx);
if (!CaptureStack(cx, &stack))
return false;
/*
* 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());
RootedObject obj(cx, ErrorObject::create(cx, exnType, stack, fileName,
lineNumber, columnNumber, nullptr, message, proto));
if (!obj)
return false;
args.rval().setObject(*obj);
return true;
}
#if JS_HAS_TOSOURCE
/*
* Return a string that may eval to something similar to the original object.
*/
static bool
exn_toSource(JSContext* cx, unsigned argc, Value* vp)
{
JS_CHECK_RECURSION(cx, return false);
CallArgs args = CallArgsFromVp(argc, vp);
RootedObject obj(cx, ToObject(cx, args.thisv()));
if (!obj)
return false;
RootedValue nameVal(cx);
RootedString name(cx);
if (!GetProperty(cx, obj, obj, cx->names().name, &nameVal) ||
!(name = ToString<CanGC>(cx, nameVal)))
{
return false;
}
RootedValue messageVal(cx);
RootedString message(cx);
if (!GetProperty(cx, obj, obj, cx->names().message, &messageVal) ||
!(message = ValueToSource(cx, messageVal)))
{
return false;
}
RootedValue filenameVal(cx);
RootedString filename(cx);
if (!GetProperty(cx, obj, obj, cx->names().fileName, &filenameVal) ||
!(filename = ValueToSource(cx, filenameVal)))
{
return false;
}
RootedValue linenoVal(cx);
uint32_t lineno;
if (!GetProperty(cx, obj, obj, cx->names().lineNumber, &linenoVal) ||
!ToUint32(cx, linenoVal, &lineno))
{
return false;
}
StringBuffer sb(cx);
if (!sb.append("(new ") || !sb.append(name) || !sb.append("("))
return false;
if (!sb.append(message))
return false;
if (!filename->empty()) {
if (!sb.append(", ") || !sb.append(filename))
return false;
}
if (lineno != 0) {
/* We have a line, but no filename, add empty string */
if (filename->empty() && !sb.append(", \"\""))
return false;
JSString* linenumber = ToString<CanGC>(cx, linenoVal);
if (!linenumber)
return false;
if (!sb.append(", ") || !sb.append(linenumber))
return false;
}
if (!sb.append("))"))
return false;
JSString* str = sb.finishString();
if (!str)
return false;
args.rval().setString(str);
return true;
}
#endif
/* 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, cx->global(),
&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;
ctor = NewFunctionWithProto(cx, Error, 1, JSFunction::NATIVE_CTOR, nullptr,
ClassName(key, cx), proto, gc::AllocKind::FUNCTION_EXTENDED,
SingletonObject);
}
if (!ctor)
return nullptr;
ctor->as<JSFunction>().setExtendedSlot(0, Int32Value(type));
return ctor;
}
JS_FRIEND_API(JSFlatString*)
js::GetErrorTypeName(JSContext* cx, int16_t exnType)
{
/*
* JSEXN_INTERNALERR returns null to prevent that "InternalError: "
* is prepended before "uncaught exception: "
*/
if (exnType < 0 || exnType >= JSEXN_LIMIT ||
exnType == JSEXN_INTERNALERR || exnType == JSEXN_WARN)
{
return nullptr;
}
JSProtoKey key = GetExceptionProtoKey(JSExnType(exnType));
return ClassName(key, cx);
}
void
js::ErrorToException(JSContext* cx, JSErrorReport* reportp,
JSErrorCallback callback, void* userRef)
{
MOZ_ASSERT(reportp);
MOZ_ASSERT(!JSREPORT_IS_WARNING(reportp->flags));
// We cannot throw a proper object inside the self-hosting compartment, as
// we cannot construct the Error constructor without self-hosted code. Just
// print the error to stderr to help debugging.
if (cx->runtime()->isSelfHostingCompartment(cx->compartment())) {
PrintError(cx, stderr, JS::ConstUTF8CharsZ(), reportp, true);
return;
}
// Find the exception index associated with this error.
JSErrNum errorNumber = static_cast<JSErrNum>(reportp->errorNumber);
if (!callback)
callback = GetErrorMessage;
const JSErrorFormatString* errorString = callback(userRef, errorNumber);
JSExnType exnType = errorString ? static_cast<JSExnType>(errorString->exnType) : JSEXN_ERR;
MOZ_ASSERT(exnType < JSEXN_LIMIT);
MOZ_ASSERT(exnType != JSEXN_NOTE);
if (exnType == JSEXN_WARN) {
// werror must be enabled, so we use JSEXN_ERR.
MOZ_ASSERT(cx->options().werror());
exnType = JSEXN_ERR;
}
// Prevent infinite recursion.
if (cx->generatingError)
return;
AutoScopedAssign<bool> asa(&cx->generatingError, true);
// Create an exception object.
RootedString messageStr(cx, reportp->newMessageString(cx));
if (!messageStr)
return;
RootedString fileName(cx, JS_NewStringCopyZ(cx, reportp->filename));
if (!fileName)
return;
uint32_t lineNumber = reportp->lineno;
uint32_t columnNumber = reportp->column;
RootedObject stack(cx);
if (!CaptureStack(cx, &stack))
return;
js::ScopedJSFreePtr<JSErrorReport> report(CopyErrorReport(cx, reportp));
if (!report)
return;
RootedObject errObject(cx, ErrorObject::create(cx, exnType, stack, fileName,
lineNumber, columnNumber, &report, messageStr));
if (!errObject)
return;
// Throw it.
cx->setPendingException(ObjectValue(*errObject));
// Flag the error report passed in to indicate an exception was raised.
reportp->flags |= JSREPORT_EXCEPTION;
}
static bool
IsDuckTypedErrorObject(JSContext* cx, HandleObject exnObject, const char** filename_strp)
{
/*
* This function is called from ErrorReport::init and so should not generate
* any new exceptions.
*/
AutoClearPendingException acpe(cx);
bool found;
if (!JS_HasProperty(cx, exnObject, js_message_str, &found) || !found)
return false;
const char* filename_str = *filename_strp;
if (!JS_HasProperty(cx, exnObject, filename_str, &found) || !found) {
/* Now try "fileName", in case this quacks like an Error */
filename_str = js_fileName_str;
if (!JS_HasProperty(cx, exnObject, filename_str, &found) || !found)
return false;
}
if (!JS_HasProperty(cx, exnObject, js_lineNumber_str, &found) || !found)
return false;
*filename_strp = filename_str;
return true;
}
static JSString*
ErrorReportToString(JSContext* cx, JSErrorReport* reportp)
{
/*
* We do NOT want to use GetErrorTypeName() here because it will not do the
* "right thing" for JSEXN_INTERNALERR. That is, the caller of this API
* expects that "InternalError: " will be prepended but GetErrorTypeName
* goes out of its way to avoid this.
*/
JSExnType type = static_cast<JSExnType>(reportp->exnType);
RootedString str(cx);
if (type != JSEXN_WARN && type != JSEXN_NOTE)
str = ClassName(GetExceptionProtoKey(type), cx);
/*
* If "str" is null at this point, that means we just want to use
* message without prefixing it with anything.
*/
if (str) {
RootedString separator(cx, JS_NewUCStringCopyN(cx, u": ", 2));
if (!separator)
return nullptr;
str = ConcatStrings<CanGC>(cx, str, separator);
if (!str)
return nullptr;
}
RootedString message(cx, reportp->newMessageString(cx));
if (!message)
return nullptr;
if (!str)
return message;
return ConcatStrings<CanGC>(cx, str, message);
}
ErrorReport::ErrorReport(JSContext* cx)
: reportp(nullptr),
str(cx),
strChars(cx),
exnObject(cx)
{
}
ErrorReport::~ErrorReport()
{
}
bool
ErrorReport::init(JSContext* cx, HandleValue exn,
SniffingBehavior sniffingBehavior)
{
MOZ_ASSERT(!cx->isExceptionPending());
MOZ_ASSERT(!reportp);
if (exn.isObject()) {
// Because ToString below could error and an exception object could become
// unrooted, we must root our exception object, if any.
exnObject = &exn.toObject();
reportp = ErrorFromException(cx, exnObject);
if (!reportp && sniffingBehavior == NoSideEffects) {
JS_ReportErrorNumberASCII(cx, GetErrorMessage, nullptr,
JSMSG_ERR_DURING_THROW);
return false;
}
}
// Be careful not to invoke ToString if we've already successfully extracted
// an error report, since the exception might be wrapped in a security
// wrapper, and ToString-ing it might throw.
if (reportp) {
str = ErrorReportToString(cx, reportp);
} else if (exn.isSymbol()) {
RootedValue strVal(cx);
if (js::SymbolDescriptiveString(cx, exn.toSymbol(), &strVal))
str = strVal.toString();
else
str = nullptr;
} else {
str = ToString<CanGC>(cx, exn);
}
if (!str)
cx->clearPendingException();
// If ErrorFromException didn't get us a JSErrorReport, then the object
// was not an ErrorObject, security-wrapped or otherwise. However, it might
// still quack like one. Give duck-typing a chance. We start by looking for
// "filename" (all lowercase), since that's where DOMExceptions store their
// filename. Then we check "fileName", which is where Errors store it. We
// have to do it in that order, because DOMExceptions have Error.prototype
// on their proto chain, and hence also have a "fileName" property, but its
// value is "".
const char* filename_str = "filename";
if (!reportp && exnObject && IsDuckTypedErrorObject(cx, exnObject, &filename_str))
{
// Temporary value for pulling properties off of duck-typed objects.
RootedValue val(cx);
RootedString name(cx);
if (JS_GetProperty(cx, exnObject, js_name_str, &val) && val.isString())
name = val.toString();
else
cx->clearPendingException();
RootedString msg(cx);
if (JS_GetProperty(cx, exnObject, js_message_str, &val) && val.isString())
msg = val.toString();
else
cx->clearPendingException();
// If we have the right fields, override the ToString we performed on
// the exception object above with something built out of its quacks
// (i.e. as much of |NameQuack: MessageQuack| as we can make).
//
// It would be nice to use ErrorReportToString here, but we can't quite
// do it - mostly because we'd need to figure out what JSExnType |name|
// corresponds to, which may not be any JSExnType at all.
if (name && msg) {
RootedString colon(cx, JS_NewStringCopyZ(cx, ": "));
if (!colon)
return false;
RootedString nameColon(cx, ConcatStrings<CanGC>(cx, name, colon));
if (!nameColon)
return false;
str = ConcatStrings<CanGC>(cx, nameColon, msg);
if (!str)
return false;
} else if (name) {
str = name;
} else if (msg) {
str = msg;
}
if (JS_GetProperty(cx, exnObject, filename_str, &val)) {
RootedString tmp(cx, ToString<CanGC>(cx, val));
if (tmp)
filename.encodeUtf8(cx, tmp);
else
cx->clearPendingException();
} else {
cx->clearPendingException();
}
uint32_t lineno;
if (!JS_GetProperty(cx, exnObject, js_lineNumber_str, &val) ||
!ToUint32(cx, val, &lineno))
{
cx->clearPendingException();
lineno = 0;
}
uint32_t column;
if (!JS_GetProperty(cx, exnObject, js_columnNumber_str, &val) ||
!ToUint32(cx, val, &column))
{
cx->clearPendingException();
column = 0;
}
reportp = &ownedReport;
new (reportp) JSErrorReport();
ownedReport.filename = filename.ptr();
ownedReport.lineno = lineno;
ownedReport.exnType = JSEXN_INTERNALERR;
ownedReport.column = column;
if (str) {
// Note that using |str| for |message_| here is kind of wrong,
// because |str| is supposed to be of the format
// |ErrorName: ErrorMessage|, and |message_| is supposed to
// correspond to |ErrorMessage|. But this is what we've
// historically done for duck-typed error objects.
//
// If only this stuff could get specced one day...
char* utf8;
if (str->ensureFlat(cx) &&
strChars.initTwoByte(cx, str) &&
(utf8 = JS::CharsToNewUTF8CharsZ(cx, strChars.twoByteRange()).c_str()))
{
ownedReport.initOwnedMessage(utf8);
} else {
cx->clearPendingException();
str = nullptr;
}
}
}
const char* utf8Message = nullptr;
if (str)
utf8Message = toStringResultBytesStorage.encodeUtf8(cx, str);
if (!utf8Message)
utf8Message = "unknown (can't convert to string)";
if (!reportp) {
// This is basically an inlined version of
//
// JS_ReportErrorNumberUTF8(cx, GetErrorMessage, nullptr,
// JSMSG_UNCAUGHT_EXCEPTION, utf8Message);
//
// but without the reporting bits. Instead it just puts all
// the stuff we care about in our ownedReport and message_.
if (!populateUncaughtExceptionReportUTF8(cx, utf8Message)) {
// Just give up. We're out of memory or something; not much we can
// do here.
return false;
}
} else {
toStringResult_ = JS::ConstUTF8CharsZ(utf8Message, strlen(utf8Message));
/* Flag the error as an exception. */
reportp->flags |= JSREPORT_EXCEPTION;
}
return true;
}
bool
ErrorReport::populateUncaughtExceptionReportUTF8(JSContext* cx, ...)
{
va_list ap;
va_start(ap, cx);
bool ok = populateUncaughtExceptionReportUTF8VA(cx, ap);
va_end(ap);
return ok;
}
bool
ErrorReport::populateUncaughtExceptionReportUTF8VA(JSContext* cx, va_list ap)
{
new (&ownedReport) JSErrorReport();
ownedReport.flags = JSREPORT_ERROR;
ownedReport.errorNumber = JSMSG_UNCAUGHT_EXCEPTION;
// XXXbz this assumes the stack we have right now is still
// related to our exception object. It would be better if we
// could accept a passed-in stack of some sort instead.
NonBuiltinFrameIter iter(cx, cx->compartment()->principals());
if (!iter.done()) {
ownedReport.filename = iter.filename();
ownedReport.lineno = iter.computeLine(&ownedReport.column);
// XXX: Make the column 1-based as in other browsers, instead of 0-based
// which is how SpiderMonkey stores it internally. This will be
// unnecessary once bug 1144340 is fixed.
++ownedReport.column;
ownedReport.isMuted = iter.mutedErrors();
}
if (!ExpandErrorArgumentsVA(cx, GetErrorMessage, nullptr,
JSMSG_UNCAUGHT_EXCEPTION,
nullptr, ArgumentsAreUTF8, &ownedReport, ap)) {
return false;
}
toStringResult_ = ownedReport.message();
reportp = &ownedReport;
return true;
}
JSObject*
js::CopyErrorObject(JSContext* cx, Handle<ErrorObject*> err)
{
js::ScopedJSFreePtr<JSErrorReport> copyReport;
if (JSErrorReport* errorReport = err->getErrorReport()) {
copyReport = CopyErrorReport(cx, errorReport);
if (!copyReport)
return nullptr;
}
RootedString message(cx, err->getMessage());
if (message && !cx->compartment()->wrap(cx, &message))
return nullptr;
RootedString fileName(cx, err->fileName(cx));
if (!cx->compartment()->wrap(cx, &fileName))
return nullptr;
RootedObject stack(cx, err->stack());
if (!cx->compartment()->wrap(cx, &stack))
return nullptr;
uint32_t lineNumber = err->lineNumber();
uint32_t columnNumber = err->columnNumber();
JSExnType errorType = err->type();
// Create the Error object.
return ErrorObject::create(cx, errorType, stack, fileName,
lineNumber, columnNumber, &copyReport, message);
}
JS_PUBLIC_API(bool)
JS::CreateError(JSContext* cx, JSExnType type, HandleObject stack, HandleString fileName,
uint32_t lineNumber, uint32_t columnNumber, JSErrorReport* report,
HandleString message, MutableHandleValue rval)
{
assertSameCompartment(cx, stack, fileName, message);
AssertObjectIsSavedFrameOrWrapper(cx, stack);
js::ScopedJSFreePtr<JSErrorReport> rep;
if (report)
rep = CopyErrorReport(cx, report);
RootedObject obj(cx,
js::ErrorObject::create(cx, type, stack, fileName,
lineNumber, columnNumber, &rep, message));
if (!obj)
return false;
rval.setObject(*obj);
return true;
}
const char*
js::ValueToSourceForError(JSContext* cx, HandleValue val, JSAutoByteString& bytes)
{
if (val.isUndefined())
return "undefined";
if (val.isNull())
return "null";
AutoClearPendingException acpe(cx);
RootedString str(cx, JS_ValueToSource(cx, val));
if (!str)
return "<<error converting value to string>>";
StringBuffer sb(cx);
if (val.isObject()) {
RootedObject valObj(cx, val.toObjectOrNull());
ESClass cls;
if (!GetBuiltinClass(cx, valObj, &cls))
return "<<error determining class of value>>";
const char* s;
if (cls == ESClass::Array)
s = "the array ";
else if (cls == ESClass::ArrayBuffer)
s = "the array buffer ";
else if (JS_IsArrayBufferViewObject(valObj))
s = "the typed array ";
else
s = "the object ";
if (!sb.append(s, strlen(s)))
return "<<error converting value to string>>";
} else if (val.isNumber()) {
if (!sb.append("the number "))
return "<<error converting value to string>>";
} else if (val.isString()) {
if (!sb.append("the string "))
return "<<error converting value to string>>";
} else {
MOZ_ASSERT(val.isBoolean() || val.isSymbol());
return bytes.encodeLatin1(cx, str);
}
if (!sb.append(str))
return "<<error converting value to string>>";
str = sb.finishString();
if (!str)
return "<<error converting value to string>>";
return bytes.encodeLatin1(cx, str);
}
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