Re: [tcljava-dev] package unknown - looking for pkgIndex.tcl in the java classpath

[Christian B. <chr...@lf...>]

Hello,

any thoughts on the patch idea? Did anyone experience problems? If you 
find the idea useful, I'll be happy to send a "real" patch (diff) for 
tclPkgUnknown.

Greetings,

Christian

Christian Brensing wrote:
> Hello,
>
> I have written for a project a patch for tclPkgUnknown that allows 
> loading a jar bundled package (or any other package available in the 
> classpath) with a root pkgIndex.tcl using 'package require foo'. It's 
> implemented by looking first for root classpath resources named 
> 'pkgIndex.tcl' and sourcing them via 'source -url' (it uses the 
> commands from the java package). The patch itself is a procedure named 
> jaclPkgUnknown which delegates to the standard tclPkgUnknown found in 
> init.tcl for scanning the auto_path directories as well. You can use 
> the classpath loading by specifying this proc as the package unknown 
> script. The proc is as follows:
>
> # jaclPkgUnknown --
> #
> #   Tcl/Java specific procedure for the "package unknown" function. It is
> #   invoked when a package that's needed can't be found. It scans 
> first the
> #   current thread's ContextClassLoader looking for root resources named
> #   pkgIndex.tcl and sources any such resources that are found to 
> setup the
> #   package database. Subsequently it calls the standard unknown 
> procedure
> #   'tclPkgUnknown' which scans the auto_path directories as well.
> #
> # Arguments:
> #   name        Name of desired package. Not used.
> #   version     Version of desired package. Not used.
> #   exact       Either "-exact" or omitted. Not used.
>
> proc jaclPkgUnknown {name version {exact {}}} {
>    package require java
>      global dir
>      if {[info exists dir]} {
>        set save_dir $dir
>    }
>      # Looking for /pkgIndex.tcl via the the thread's ContextClassLoader
>    set tccl [[java::call Thread currentThread] getContextClassLoader]
>    set urls [$tccl getResources pkgIndex.tcl]
>    while {[$urls hasMoreElements]} {
>        set url [[$urls nextElement] toString]
>        if {[string first "file:" $url] == 0} {
>            # Extract the path from the file url and set dir to its parent
>            set filename [string range $url 5 [string length $url]]
>            set dir [file dirname $filename]
>        } elseif {[string first "jar:file:" $url] == 0} {
>            # Set dir to a root resource location
>            set dir "resource:/"
>        } else {
>            tclLog "can't read package index from url \"$url\": 
> protocol not supported"
>            continue
>        }
>              if [catch {source -url $url} msg] {
>            error "error reading package index file from url \"$url\": 
> $msg"
>        }
>    }
>      # Delegate to standard unknown procedure
>    tclPkgUnknown $name $version $exact
>      if {[info exists save_dir]} {
>        set dir $save_dir
>    } else {
>        unset dir
>    }
> }
>
> The proc doesn't function if the sourced pkgIndex.tcl (found in a jar 
> file) uses file globbing since dir is set to resource:/.
>
> I hope the patch will be useful.
>
> Greetings from Munich,
>
> Christian
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