AuroraMiddleware/v8
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Added .message accessor to messages. This gives you the same

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descriptive message as is used to construct the toString() for an
error object.


git-svn-id: http://v8.googlecode.com/svn/branches/bleeding_edge@1451 ce2b1a6d-e550-0410-aec6-3dcde31c8c00
This commit is contained in:
christian.plesner.hansen@gmail.com 2009-03-09 12:50:32 +00:00
parent ee2601dc3b
commit 36dd91c562
1 changed files with 31 additions and 2 deletions
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33
src/messages.js
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@ -153,7 +153,7 @@ function MakeGenericError(constructor, type, args) {
args = [];
}
var e = new constructor();
var e = new constructor(kAddMessageAccessorsMarker);
e.type = type;
e.arguments = args;
return e;
@ -589,6 +589,29 @@ function UnsafeGetStackTraceLine(recv, fun, pos, isTopLevel) {
// ----------------------------------------------------------------------------
// Error implementation
// If this object gets passed to an error constructor the error will
// get an accessor for .message that constructs a descriptive error
// message on access.
var kAddMessageAccessorsMarker = { };
// Defines accessors for a property that is calculated the first time
// the property is read and then replaces the accessor with the value.
// Also, setting the property causes the accessors to be deleted.
function DefineOneShotAccessor(obj, name, fun) {
// Note that the accessors consistently operate on 'obj', not 'this'.
// Since the object may occur in someone else's prototype chain we
// can't rely on 'this' being the same as 'obj'.
obj.__defineGetter__(name, function () {
var value = fun(obj);
obj[name] = value;
return value;
});
obj.__defineSetter__(name, function (v) {
delete obj[name];
obj[name] = v;
});
}
function DefineError(f) {
// Store the error function in both the global object
// and the runtime object. The function is fetched
@ -607,7 +630,13 @@ function DefineError(f) {
f.prototype.name = name;
%SetCode(f, function(m) {
if (%IsConstructCall()) {
if (!IS_UNDEFINED(m)) this.message = ToString(m);
if (m === kAddMessageAccessorsMarker) {
DefineOneShotAccessor(this, 'message', function (obj) {
return FormatMessage({type: obj.type, args: obj.arguments});
});
} else if (!IS_UNDEFINED(m)) {
this.message = ToString(m);
}
} else {
return new f(m);
}