[webkit-dev] Custom exception messages for IDL defined methods that raise DOMException.

Adam Barth abarth at webkit.org
Mon Nov 14 17:17:34 PST 2011

For SQLException, there are a hundred exception codes reserved,

    static const int SQLExceptionOffset = 1000;
    static const int SQLExceptionMax = 1099;

of which, we appear to only be using eight.  It sounds like you're
considering exposing more than a finite enumerated number of error
codes, however.  Do we really want to make SQLite error messages part
of the web platform?  What if we want to upgrade to a newer version of
SQLite in the future (which might have different error codes)?

IMHO, we shouldn't be investing much more effort into WebSQLDatabase.
It's something of a dead-end for the platform.  If you're set on
investing more effort, one path forward is to figure out which are the
most important kinds of errors to distinguish and to give them error
codes.  You can then give them descriptions as usual without needing
any custom bindings.


On Mon, Nov 14, 2011 at 4:58 PM, Michael Nordman <michaeln at google.com> wrote:
> I guess the exception of interest is  SQLException.
> Take a look at Database.cpp line 103. The ' errorMessage' string on that
> line contains more detailed information about what went wrong in the act of
> opening the database, including things like an sqlite error code and sqlite
> error message. These strings are formed in the bowls of
> AbstractDatabase::performOpenAndVerify().
> On Mon, Nov 14, 2011 at 4:48 PM, Adam Barth <abarth at webkit.org> wrote:
>> I'm not sure exactly what you're trying to do, but one option is to
>> add a new type of DOMException:
>> http://trac.webkit.org/browser/trunk/Source/WebCore/dom/DOMExceptions.in
>> Another option is to customize the message from an existing exception
>> (here are the DOMCore exceptions):
>> http://trac.webkit.org/browser/trunk/Source/WebCore/dom/DOMCoreException.cpp
>> If you show me the spec you're trying to implement, I might have a
>> more concept suggestion of the best way to implement it.
>> Adam
>> On Mon, Nov 14, 2011 at 4:44 PM, Michael Nordman <michaeln at google.com>
>> wrote:
>> > I have a case where given an IDL defined method thats defined to raise a
>> > DOMException, I'd like to set a custom exception message from within the
>> > webcore implementation and have that message percolate up into script
>> > via
>> > the bindings layer(s) and be accessible as the exception.message
>> > attribute.
>> > I don't see a non-custom way of doing that and am wondering if there
>> > should
>> > be support for something like this w/o having to resort to custom
>> > bindings?
>> > The particular methods I'm looking at are the openDatabase(...) method
>> > of
>> > DOMWindow and WorkerContext, but this seems like it might be useful in
>> > other
>> > cases as well.
>> >
>> > _______________________________________________
>> > webkit-dev mailing list
>> > webkit-dev at lists.webkit.org
>> > http://lists.webkit.org/mailman/listinfo.cgi/webkit-dev
>> >
>> >

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