Java compiler patch: compile resource files into executables

[Zack Weinberg]

On Sun, Sep 02, 2001 at 09:21:40PM -0700, Anthony Green wrote:
> Zack wrote:
> > This facility will be useful to programs written in other languages.
> > Would you mind documenting the format of the .o file generated by gcj
> > in this mode, so that a C program could make use of it?
> 
> Ok.  Where would you like to see these docs?  Comments in source?  Or texinfo?

Texinfo, ideally, since it is a user-useful feature.

> It's basically a couple of unsigned longs followed by the resource
> name and data.  The .o also contains a constructor function for
> calling _Jv_RegisterResource with a pointer to this whole mess.  I
> plan to add a -z# option to compress the resource data.  The java
> runtime change to support this is trivial, and jc1 already links in
> zlib.

Let me give a simple example of the sort of code one would like to be
able to write.  The appended shell script generates a self-extracting
archive.  What needs to be documented is what the embedded C program
should do instead of declaring and using the arch_length and arch_data
externs.

(There would be less trivial applications that wanted to have access
to the resource name and properties (if any) as well, of course.)

zw

#! /bin/sh

mkdir /tmp/sea$$ || exit 1
tar cf - $2 | gzip > /tmp/sea$$/arch.tar.gz
cat > /tmp/sea$$/code.c <<\EOF
#include <stdio.h>

extern size_t arch_length;
extern unsigned char arch_data[];

int
main(void)
{
    /* error checks left out for brevity */
    FILE *pipe = popen("zcat | tar xf -", "w");
    fwrite(arch_data, 1, arch_length, pipe);
    return !!pclose(pipe);
}
EOF

gcj -R arch -o /tmp/sea$$/arch.o /tmp/sea$$/arch.tar.gz
gcc -c -o /tmp/sea$$/code.o /tmp/sea$$/code.c
gcc -o $1 /tmp/sea$$/code.o /tmp/sea$$/arch.o
rm -rf /tmp/sea$$