1 files changed, 274 insertions, 0 deletions
diff --git a/js/src/vm/ErrorObject.cpp b/js/src/vm/ErrorObject.cpp
new file mode 100644
index 000000000..47b61b57b
--- /dev/null
+++ b/js/src/vm/ErrorObject.cpp
@@ -0,0 +1,274 @@
+/* -*- Mode: C++; tab-width: 8; indent-tabs-mode: nil; c-basic-offset: 4 -*-
+ * vim: set ts=8 sw=4 et tw=78:
+ *
+ * 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
+ErrorObject_checkAndUnwrapThis(JSContext* cx, CallArgs& args, const char* fnName,
+                               MutableHandle<ErrorObject*> error)
+{
+    const Value& thisValue = args.thisv();
+
+    if (!thisValue.isObject()) {
+        JS_ReportErrorNumberASCII(cx, GetErrorMessage, nullptr, JSMSG_NOT_NONNULL_OBJECT,
+                                  InformalValueTypeName(thisValue));
+        return false;
+    }
+
+    // Walk up the prototype chain until we find the first ErrorObject that has
+    // the slots we need. This allows us to support the poor-man's subclassing
+    // of error: Object.create(Error.prototype).
+
+    RootedObject target(cx, CheckedUnwrap(&thisValue.toObject()));
+    if (!target) {
+        JS_ReportErrorASCII(cx, "Permission denied to access object");
+        return false;
+    }
+
+    RootedObject proto(cx);
+    while (!target->is<ErrorObject>()) {
+        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, fnName, thisValue.toObject().getClass()->name);
+            return false;
+        }
+
+        target = CheckedUnwrap(proto);
+        if (!target) {
+            JS_ReportErrorASCII(cx, "Permission denied to access object");
+            return false;
+        }
+    }
+
+    error.set(&target->as<ErrorObject>());
+    return true;
+}
+
+/* static */ bool
+js::ErrorObject::getStack(JSContext* cx, unsigned argc, Value* vp)
+{
+    CallArgs args = CallArgsFromVp(argc, vp);
+    Rooted<ErrorObject*> error(cx);
+    if (!ErrorObject_checkAndUnwrapThis(cx, args, "(get stack)", &error))
+        return false;
+
+    RootedObject savedFrameObj(cx, error->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 MOZ_ALWAYS_INLINE bool
+IsObject(HandleValue v)
+{
+    return v.isObject();
+}
+
+/* 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)
+{
+    const Value& thisValue = args.thisv();
+    MOZ_ASSERT(thisValue.isObject());
+    RootedObject thisObj(cx, &thisValue.toObject());
+
+    if (!args.requireAtLeast(cx, "(set stack)", 1))
+        return false;
+    RootedValue val(cx, args[0]);
+
+    return DefineProperty(cx, thisObj, cx->names().stack, val);
+}