https://github.com/mozilla/gecko-dev
Tip revision: 284f5c756bb7b0f967dc6ec76c7ddbf856d3bc07 authored by Carsten "Tomcat" Book on 14 December 2015, 07:24:17 UTC
merge mozilla-aurora to b2g44 a=merge
merge mozilla-aurora to b2g44 a=merge
Tip revision: 284f5c7
jsexn.cpp
/* -*- 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 <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 "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);
bool
Error(JSContext* cx, unsigned argc, Value* vp);
static bool
exn_toSource(JSContext* cx, unsigned argc, Value* vp);
static const JSPropertySpec exception_properties[] = {
JS_PSGS("stack", ErrorObject::getStack, ErrorObject::setStack, 0),
JS_PS_END
};
static const JSFunctionSpec exception_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
};
#define IMPLEMENT_ERROR_SUBCLASS(name) \
{ \
js_Error_str, /* yes, really */ \
JSCLASS_HAS_CACHED_PROTO(JSProto_##name) | \
JSCLASS_HAS_RESERVED_SLOTS(ErrorObject::RESERVED_SLOTS), \
nullptr, /* addProperty */ \
nullptr, /* delProperty */ \
nullptr, /* getProperty */ \
nullptr, /* setProperty */ \
nullptr, /* enumerate */ \
nullptr, /* resolve */ \
nullptr, /* mayResolve */ \
exn_finalize, \
nullptr, /* call */ \
nullptr, /* hasInstance */ \
nullptr, /* construct */ \
nullptr, /* trace */ \
{ \
ErrorObject::createConstructor, \
ErrorObject::createProto, \
nullptr, \
nullptr, \
exception_methods, \
exception_properties, \
nullptr, \
JSProto_Error \
} \
}
const Class
ErrorObject::classes[JSEXN_LIMIT] = {
{
js_Error_str,
JSCLASS_HAS_CACHED_PROTO(JSProto_Error) |
JSCLASS_HAS_RESERVED_SLOTS(ErrorObject::RESERVED_SLOTS),
nullptr, /* addProperty */
nullptr, /* delProperty */
nullptr, /* getProperty */
nullptr, /* setProperty */
nullptr, /* enumerate */
nullptr, /* resolve */
nullptr, /* mayResolve */
exn_finalize,
nullptr, /* call */
nullptr, /* hasInstance */
nullptr, /* construct */
nullptr, /* trace */
{
ErrorObject::createConstructor,
ErrorObject::createProto,
nullptr,
nullptr,
exception_methods,
exception_properties,
nullptr
}
},
IMPLEMENT_ERROR_SUBCLASS(InternalError),
IMPLEMENT_ERROR_SUBCLASS(EvalError),
IMPLEMENT_ERROR_SUBCLASS(RangeError),
IMPLEMENT_ERROR_SUBCLASS(ReferenceError),
IMPLEMENT_ERROR_SUBCLASS(SyntaxError),
IMPLEMENT_ERROR_SUBCLASS(TypeError),
IMPLEMENT_ERROR_SUBCLASS(URIError)
};
JSErrorReport*
js::CopyErrorReport(JSContext* cx, JSErrorReport* report)
{
/*
* We use a single malloc block to make a deep copy of JSErrorReport with
* the following layout:
* JSErrorReport
* array of copies of report->messageArgs
* char16_t array with characters for all messageArgs
* char16_t array with characters for ucmessage
* char16_t array with characters for uclinebuf and uctokenptr
* char array with characters for linebuf and tokenptr
* char array with characters for filename
* Such layout together with the properties enforced by the following
* asserts does not need any extra alignment padding.
*/
JS_STATIC_ASSERT(sizeof(JSErrorReport) % sizeof(const char*) == 0);
JS_STATIC_ASSERT(sizeof(const char*) % sizeof(char16_t) == 0);
size_t filenameSize;
size_t linebufSize;
size_t uclinebufSize;
size_t ucmessageSize;
size_t i, argsArraySize, argsCopySize, argSize;
size_t mallocSize;
JSErrorReport* copy;
uint8_t* cursor;
#define JS_CHARS_SIZE(chars) ((js_strlen(chars) + 1) * sizeof(char16_t))
filenameSize = report->filename ? strlen(report->filename) + 1 : 0;
linebufSize = report->linebuf ? strlen(report->linebuf) + 1 : 0;
uclinebufSize = report->uclinebuf ? JS_CHARS_SIZE(report->uclinebuf) : 0;
ucmessageSize = 0;
argsArraySize = 0;
argsCopySize = 0;
if (report->ucmessage) {
ucmessageSize = JS_CHARS_SIZE(report->ucmessage);
if (report->messageArgs) {
for (i = 0; report->messageArgs[i]; ++i)
argsCopySize += JS_CHARS_SIZE(report->messageArgs[i]);
/* Non-null messageArgs should have at least one non-null arg. */
MOZ_ASSERT(i != 0);
argsArraySize = (i + 1) * sizeof(const char16_t*);
}
}
/*
* The mallocSize can not overflow since it represents the sum of the
* sizes of already allocated objects.
*/
mallocSize = sizeof(JSErrorReport) + argsArraySize + argsCopySize +
ucmessageSize + uclinebufSize + linebufSize + filenameSize;
cursor = cx->pod_malloc<uint8_t>(mallocSize);
if (!cursor)
return nullptr;
copy = (JSErrorReport*)cursor;
memset(cursor, 0, sizeof(JSErrorReport));
cursor += sizeof(JSErrorReport);
if (argsArraySize != 0) {
copy->messageArgs = (const char16_t**)cursor;
cursor += argsArraySize;
for (i = 0; report->messageArgs[i]; ++i) {
copy->messageArgs[i] = (const char16_t*)cursor;
argSize = JS_CHARS_SIZE(report->messageArgs[i]);
js_memcpy(cursor, report->messageArgs[i], argSize);
cursor += argSize;
}
copy->messageArgs[i] = nullptr;
MOZ_ASSERT(cursor == (uint8_t*)copy->messageArgs[0] + argsCopySize);
}
if (report->ucmessage) {
copy->ucmessage = (const char16_t*)cursor;
js_memcpy(cursor, report->ucmessage, ucmessageSize);
cursor += ucmessageSize;
}
if (report->uclinebuf) {
copy->uclinebuf = (const char16_t*)cursor;
js_memcpy(cursor, report->uclinebuf, uclinebufSize);
cursor += uclinebufSize;
if (report->uctokenptr) {
copy->uctokenptr = copy->uclinebuf + (report->uctokenptr -
report->uclinebuf);
}
}
if (report->linebuf) {
copy->linebuf = (const char*)cursor;
js_memcpy(cursor, report->linebuf, linebufSize);
cursor += linebufSize;
if (report->tokenptr) {
copy->tokenptr = copy->linebuf + (report->tokenptr -
report->linebuf);
}
}
if (report->filename) {
copy->filename = (const char*)cursor;
js_memcpy(cursor, report->filename, filenameSize);
}
MOZ_ASSERT(cursor + filenameSize == (uint8_t*)copy + mallocSize);
/* Copy non-pointer members. */
copy->isMuted = report->isMuted;
copy->lineno = report->lineno;
copy->column = report->column;
copy->errorNumber = report->errorNumber;
copy->exnType = report->exnType;
/* Note that this is before it gets flagged with JSREPORT_EXCEPTION */
copy->flags = report->flags;
#undef JS_CHARS_SIZE
return copy;
}
struct SuppressErrorsGuard
{
JSContext* cx;
JSErrorReporter prevReporter;
JS::AutoSaveExceptionState prevState;
explicit SuppressErrorsGuard(JSContext* cx)
: cx(cx),
prevReporter(JS_SetErrorReporter(cx->runtime(), nullptr)),
prevState(cx)
{}
~SuppressErrorsGuard()
{
JS_SetErrorReporter(cx->runtime(), 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, 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)
{
if (JSErrorReport* report = obj->as<ErrorObject>().getErrorReport())
fop->free_(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;
return obj->as<ErrorObject>().getOrCreateErrorReport(cx);
}
JS_PUBLIC_API(JSObject*)
ExceptionStackOrNull(JSContext* cx, HandleObject objArg)
{
AssertHeapIsIdle(cx);
CHECK_REQUEST(cx);
assertSameCompartment(cx, objArg);
RootedObject obj(cx, 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);
/* 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.scriptFilename())
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));
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)
{
RootedObject errorProto(cx, GenericCreatePrototype(cx, key));
if (!errorProto)
return nullptr;
Rooted<ErrorObject*> err(cx, &errorProto->as<ErrorObject>());
RootedString emptyStr(cx, cx->names().empty);
JSExnType type = ExnTypeFromProtoKey(key);
if (!ErrorObject::init(cx, err, type, nullptr, emptyStr, nullptr, 0, 0, emptyStr))
return nullptr;
// The various prototypes also have .name in addition to the normal error
// instance properties.
RootedPropertyName name(cx, ClassName(key, cx));
RootedValue nameValue(cx, StringValue(name));
if (!DefineProperty(cx, err, cx->names().name, nameValue, nullptr, nullptr, 0))
return nullptr;
return errorProto;
}
/* static */ JSObject*
ErrorObject::createConstructor(JSContext* cx, JSProtoKey key)
{
RootedObject ctor(cx);
ctor = GenericCreateConstructor<Error, 1, gc::AllocKind::FUNCTION_EXTENDED>(cx, key);
if (!ctor)
return nullptr;
ctor->as<JSFunction>().setExtendedSlot(0, Int32Value(ExnTypeFromProtoKey(key)));
return ctor;
}
JS_FRIEND_API(JSFlatString*)
js::GetErrorTypeName(JSRuntime* rt, int16_t exnType)
{
/*
* JSEXN_INTERNALERR returns null to prevent that "InternalError: "
* is prepended before "uncaught exception: "
*/
if (exnType <= JSEXN_NONE || exnType >= JSEXN_LIMIT ||
exnType == JSEXN_INTERNALERR)
{
return nullptr;
}
JSProtoKey key = GetExceptionProtoKey(JSExnType(exnType));
return ClassName(key, rt);
}
bool
js::ErrorToException(JSContext* cx, const char* message, JSErrorReport* reportp,
JSErrorCallback callback, void* userRef)
{
// Tell our caller to report immediately if this report is just a warning.
MOZ_ASSERT(reportp);
if (JSREPORT_IS_WARNING(reportp->flags))
return false;
// 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_NONE;
MOZ_ASSERT(exnType < JSEXN_LIMIT);
// Return false (no exception raised) if no exception is associated
// with the given error number.
if (exnType == JSEXN_NONE)
return false;
// Prevent infinite recursion.
if (cx->generatingError)
return false;
AutoScopedAssign<bool> asa(&cx->generatingError, true);
// Create an exception object.
RootedString messageStr(cx, reportp->ucmessage ? JS_NewUCStringCopyZ(cx, reportp->ucmessage)
: JS_NewStringCopyZ(cx, message));
if (!messageStr)
return cx->isExceptionPending();
RootedString fileName(cx, JS_NewStringCopyZ(cx, reportp->filename));
if (!fileName)
return cx->isExceptionPending();
uint32_t lineNumber = reportp->lineno;
uint32_t columnNumber = reportp->column;
RootedObject stack(cx);
if (!CaptureStack(cx, &stack))
return cx->isExceptionPending();
js::ScopedJSFreePtr<JSErrorReport> report(CopyErrorReport(cx, reportp));
if (!report)
return cx->isExceptionPending();
RootedObject errObject(cx, ErrorObject::create(cx, exnType, stack, fileName,
lineNumber, columnNumber, &report, messageStr));
if (!errObject)
return cx->isExceptionPending();
// Throw it.
RootedValue errValue(cx, ObjectValue(*errObject));
JS_SetPendingException(cx, errValue);
// Flag the error report passed in to indicate an exception was raised.
reportp->flags |= JSREPORT_EXCEPTION;
return true;
}
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;
}
JS_FRIEND_API(JSString*)
js::ErrorReportToString(JSContext* cx, JSErrorReport* reportp)
{
JSExnType type = static_cast<JSExnType>(reportp->exnType);
RootedString str(cx, cx->runtime()->emptyString);
if (type != JSEXN_NONE)
str = ClassName(GetExceptionProtoKey(type), cx);
RootedString toAppend(cx, JS_NewUCStringCopyN(cx, MOZ_UTF16(": "), 2));
if (!str || !toAppend)
return nullptr;
str = ConcatStrings<CanGC>(cx, str, toAppend);
if (!str)
return nullptr;
toAppend = JS_NewUCStringCopyZ(cx, reportp->ucmessage);
if (toAppend)
str = ConcatStrings<CanGC>(cx, str, toAppend);
return str;
}
bool
js::ReportUncaughtException(JSContext* cx)
{
if (!cx->isExceptionPending())
return true;
RootedValue exn(cx);
if (!cx->getPendingException(&exn)) {
cx->clearPendingException();
return false;
}
cx->clearPendingException();
ErrorReport err(cx);
if (!err.init(cx, exn)) {
cx->clearPendingException();
return false;
}
cx->setPendingException(exn);
CallErrorReporter(cx, err.message(), err.report());
cx->clearPendingException();
return true;
}
ErrorReport::ErrorReport(JSContext* cx)
: reportp(nullptr),
message_(nullptr),
ownedMessage(nullptr),
str(cx),
strChars(cx),
exnObject(cx)
{
}
ErrorReport::~ErrorReport()
{
if (!ownedMessage)
return;
js_free(ownedMessage);
if (ownedReport.messageArgs) {
/*
* ExpandErrorArgumentsVA owns its messageArgs only if it had to
* inflate the arguments (from regular |char*|s), which is always in
* our case.
*/
size_t i = 0;
while (ownedReport.messageArgs[i])
js_free(const_cast<char16_t*>(ownedReport.messageArgs[i++]));
js_free(ownedReport.messageArgs);
}
js_free(const_cast<char16_t*>(ownedReport.ucmessage));
}
void
ErrorReport::ReportAddonExceptionToTelementry(JSContext* cx)
{
MOZ_ASSERT(exnObject);
RootedObject unwrapped(cx, UncheckedUnwrap(exnObject));
MOZ_ASSERT(unwrapped, "UncheckedUnwrap failed?");
// There is not much we can report if the exception is not an ErrorObject, let's ignore those.
if (!unwrapped->is<ErrorObject>())
return;
Rooted<ErrorObject*> errObj(cx, &unwrapped->as<ErrorObject>());
RootedObject stack(cx, errObj->stack());
// Let's ignore TOP level exceptions. For regular add-ons those will not be reported anyway,
// for SDK based once it should not be a valid case either.
// At this point the frame stack is unwound but the exception object stored the stack so let's
// use that for getting the function name.
if (!stack)
return;
JSCompartment* comp = stack->compartment();
JSAddonId* addonId = comp->addonId;
// We only want to send the report if the scope that just have thrown belongs to an add-on.
// Let's check the compartment of the youngest function on the stack, to determine that.
if (!addonId)
return;
RootedString funnameString(cx);
JS::SavedFrameResult result = GetSavedFrameFunctionDisplayName(cx, stack, &funnameString);
// AccessDenied should never be the case here for add-ons but let's not risk it.
JSAutoByteString bytes;
const char* funname = nullptr;
bool denied = result == JS::SavedFrameResult::AccessDenied;
funname = denied ? "unknown"
: funnameString ? AtomToPrintableString(cx,
&funnameString->asAtom(),
&bytes)
: "anonymous";
UniqueChars addonIdChars(JS_EncodeString(cx, addonId));
const char* filename = nullptr;
if (reportp && reportp->filename) {
filename = strrchr(reportp->filename, '/');
if (filename)
filename++;
}
if (!filename) {
filename = "FILE_NOT_FOUND";
}
char histogramKey[64];
JS_snprintf(histogramKey, sizeof(histogramKey),
"%s %s %s %u",
addonIdChars.get(),
funname,
filename,
(reportp ? reportp->lineno : 0) );
cx->runtime()->addTelemetry(JS_TELEMETRY_ADDON_EXCEPTIONS, 1, histogramKey);
}
bool
ErrorReport::init(JSContext* cx, HandleValue exn)
{
MOZ_ASSERT(!cx->isExceptionPending());
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);
// Let's see if the exception is from add-on code, if so, it should be reported
// to telementry.
ReportAddonExceptionToTelementry(cx);
}
// 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
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 = int16_t(JSEXN_NONE);
ownedReport.column = column;
if (str) {
// Note that using |str| for |ucmessage| here is kind of wrong,
// because |str| is supposed to be of the format
// |ErrorName: ErrorMessage|, and |ucmessage| 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...
if (str->ensureFlat(cx) && strChars.initTwoByte(cx, str))
ownedReport.ucmessage = strChars.twoByteChars();
}
}
if (str)
message_ = bytesStorage.encodeUtf8(cx, str);
if (!message_)
message_ = "unknown (can't convert to string)";
if (!reportp) {
// This is basically an inlined version of
//
// JS_ReportErrorNumber(cx, GetErrorMessage, nullptr,
// JSMSG_UNCAUGHT_EXCEPTION, message_);
//
// but without the reporting bits. Instead it just puts all
// the stuff we care about in our ownedReport and message_.
if (!populateUncaughtExceptionReport(cx, message_)) {
// Just give up. We're out of memory or something; not much we can
// do here.
return false;
}
} else {
/* Flag the error as an exception. */
reportp->flags |= JSREPORT_EXCEPTION;
}
return true;
}
bool
ErrorReport::populateUncaughtExceptionReport(JSContext* cx, ...)
{
va_list ap;
va_start(ap, cx);
bool ok = populateUncaughtExceptionReportVA(cx, ap);
va_end(ap);
return ok;
}
bool
ErrorReport::populateUncaughtExceptionReportVA(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.scriptFilename();
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, &ownedMessage,
&ownedReport, ArgumentsAreASCII, ap)) {
return false;
}
reportp = &ownedReport;
message_ = ownedMessage;
ownsMessageAndReport = true;
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, ©Report, 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";
}
RootedString str(cx, JS_ValueToSource(cx, val));
if (!str) {
JS_ClearPendingException(cx);
return "<<error converting value to string>>";
}
StringBuffer sb(cx);
if (val.isObject()) {
RootedObject valObj(cx, val.toObjectOrNull());
ESClassValue cls;
if (!GetBuiltinClass(cx, valObj, &cls)) {
JS_ClearPendingException(cx);
return "<<error determining class of value>>";
}
if (cls == ESClass_Array) {
sb.append("the array ");
} else if (cls == ESClass_ArrayBuffer) {
sb.append("the array buffer ");
} else if (JS_IsArrayBufferViewObject(valObj)) {
sb.append("the typed array ");
} else {
sb.append("the object ");
}
} else if (val.isNumber()) {
sb.append("the number ");
} else if (val.isString()) {
sb.append("the string ");
} else {
MOZ_ASSERT(val.isBoolean() || val.isSymbol());
return bytes.encodeLatin1(cx, str);
}
sb.append(str);
return bytes.encodeLatin1(cx, sb.finishString());
}