[cp-patches] Re: Absolute URL parsing bug

[Per Bothner]

Andrew Haley wrote:
> This URL is an absolute URL because its path begins with a "/":
>
> "jar:file:/usr/src/redhat/BUILD/jonas-4.3.3/jonas/output/JONAS_4_3_3/examples/webservices/beans/ws/temp/ejbjars/ws.jar!/META-INF/wsdl/ssbEndpoint.wsdl"
>
> [ An absolute file URL can look like:
>
>    absoluteURI = "file" ":" abs_path
>    abs_path = "/" path_segments
>
> That is, there is no need for "//".

I don't see that in any of the specs.  Technically, "file:/tmp/foo.html" 
is not a valid URI, as far as I can tell.  I notice that firefox 
rewrites it (in the navigation bar) to "file:///tmp/foo.html".

Now in practice we may want to allow "file:/tmp/foo.html", but it should 
be viewed as an unofficial short-hand for "file:///tmp/foo.html".

> And indeed, the URL spec in the
> SDK docs says 'If the spec's path component begins with a slash
> character "/" then the path is treated as absolute...' ]

The *path* is absolute, but the URI isn't.

This matters when resolving a relative URL against a base URI, such as 
he URL of the containing document.

If we have a base URI "http://bar.com/baz/index.html"; and a reference 
"/tmp/foo.html" then the resolved URI is "http://bar.com/tmp/foo.html";.

> But we parse the spec looking for "//" to determine if a URL is
> absolute,

A URL is absolute *only* if it has a "scheme".