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/* -*- Mode: C++; tab-width: 8; indent-tabs-mode: nil; c-basic-offset: 4 -*-
*
* 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/Range.h"
#include "jsexn.h"
#include "js/CallArgs.h"
#include "js/CharacterEncoding.h"
#include "vm/GlobalObject.h"
#include "vm/String.h"
#include "jsobjinlines.h"
#include "vm/NativeObject-inl.h"
#include "vm/SavedStacks-inl.h"
#include "vm/Shape-inl.h"
using namespace js;
/* static */ Shape*
js::ErrorObject::assignInitialShape(ExclusiveContext* cx, Handle<ErrorObject*> obj)
{
MOZ_ASSERT(obj->empty());
if (!obj->addDataProperty(cx, cx->names().fileName, FILENAME_SLOT, 0))
return nullptr;
if (!obj->addDataProperty(cx, cx->names().lineNumber, LINENUMBER_SLOT, 0))
return nullptr;
return obj->addDataProperty(cx, cx->names().columnNumber, COLUMNNUMBER_SLOT, 0);
}
/* static */ bool
js::ErrorObject::init(JSContext* cx, Handle<ErrorObject*> obj, JSExnType type,
ScopedJSFreePtr<JSErrorReport>* errorReport, HandleString fileName,
HandleObject stack, uint32_t lineNumber, uint32_t columnNumber,
HandleString message)
{
AssertObjectIsSavedFrameOrWrapper(cx, stack);
assertSameCompartment(cx, obj, stack);
// Null out early in case of error, for exn_finalize's sake.
obj->initReservedSlot(ERROR_REPORT_SLOT, PrivateValue(nullptr));
if (!EmptyShape::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()|.
RootedShape messageShape(cx);
if (message) {
messageShape = obj->addDataProperty(cx, cx->names().message, MESSAGE_SLOT, 0);
if (!messageShape)
return false;
MOZ_ASSERT(messageShape->slot() == MESSAGE_SLOT);
}
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(JSEXN_ERR <= type && type < JSEXN_LIMIT);
JSErrorReport* report = errorReport ? errorReport->forget() : nullptr;
obj->initReservedSlot(EXNTYPE_SLOT, Int32Value(type));
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));
if (message)
obj->setSlotWithType(cx, messageShape, StringValue(message));
return true;
}
/* static */ ErrorObject*
js::ErrorObject::create(JSContext* cx, JSExnType errorType, HandleObject stack,
HandleString fileName, uint32_t lineNumber, uint32_t columnNumber,
ScopedJSFreePtr<JSErrorReport>* report, HandleString message,
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 Class* clasp = ErrorObject::classForType(errorType);
JSObject* obj = NewObjectWithGivenProto(cx, clasp, proto);
if (!obj)
return nullptr;
errObject = &obj->as<ErrorObject>();
}
if (!ErrorObject::init(cx, errObject, errorType, report, fileName, stack,
lineNumber, columnNumber, message))
{
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.
JSAutoByteString filenameStr;
if (!filenameStr.encodeLatin1(cx, fileName(cx)))
return nullptr;
report.filename = filenameStr.ptr();
// Coordinates.
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;
if (!message->ensureFlat(cx))
return nullptr;
UniquePtr<char[], JS::FreePolicy> utf8 = StringToNewUTF8CharsZ(cx, *message);
if (!utf8)
return nullptr;
report.initOwnedMessage(utf8.release());
// Cache and return.
JSErrorReport* copy = CopyErrorReport(cx, &report);
if (!copy)
return nullptr;
setReservedSlot(ERROR_REPORT_SLOT, PrivateValue(copy));
return copy;
}
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 target(cx, CheckedUnwrap(obj));
if (!target) {
JS_ReportErrorASCII(cx, "Permission denied to access object");
return false;
}
RootedObject proto(cx);
while (!IsErrorProtoKey(StandardProtoKeyOrNull(target))) {
if (!GetPrototype(cx, target, &proto))
return false;
if (!proto) {
// We walked the whole prototype chain and did not find an Error
// object.
JS_ReportErrorNumberASCII(cx, GetErrorMessage, nullptr, JSMSG_INCOMPATIBLE_PROTO,
js_Error_str, "(get stack)", obj->getClass()->name);
return false;
}
target = CheckedUnwrap(proto);
if (!target) {
JS_ReportErrorASCII(cx, "Permission denied to access object");
return false;
}
}
result.set(target);
return true;
}
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;
}
RootedObject savedFrameObj(cx, obj->as<ErrorObject>().stack());
RootedString stackString(cx);
if (!BuildStackString(cx, savedFrameObj, &stackString))
return false;
if (cx->stackFormat() == js::StackFormat::V8) {
// When emulating V8 stack frames, we also need to prepend the
// stringified Error to the stack string.
HandlePropertyName name = cx->names().ErrorToStringWithTrailingNewline;
RootedValue val(cx);
if (!GlobalObject::getSelfHostedFunction(cx, cx->global(), name, name, 0, &val))
return false;
RootedValue rval(cx);
if (!js::Call(cx, val, args.thisv(), &rval))
return false;
if (!rval.isString())
return false;
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 DefineProperty(cx, thisObj, cx->names().stack, val);
}
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