new module 'javaversion'

[Bruno Haible]

For the javacomp module, it is necessary to know which java version
the java executer understands. (That means both the bytecoded class
version number as well as the API level.)

I added this new module.

========================= modules/javaversion ============================
Description:
Determine the Java version supported by javaexec.

Files:
lib/javaversion.h
lib/javaversion.c
lib/javaversion.java
lib/javaversion.class

Depends-on:
javaexec
stdbool
pipe
wait-process
getline
gettext-h

configure.ac:

Makefile.am:
lib_SOURCES += javaversion.h javaversion.c

Include:
"javaversion.h"

License:
GPL

Maintainer:
Bruno Haible

============================ lib/javaversion.h ===========================
/* Determine the Java version supported by javaexec.
   Copyright (C) 2006 Free Software Foundation, Inc.
   Written by Bruno Haible <address@hidden>, 2006.

   This program is free software; you can redistribute it and/or modify
   it under the terms of the GNU General Public License as published by
   the Free Software Foundation; either version 2, or (at your option)
   any later version.

   This program is distributed in the hope that it will be useful,
   but WITHOUT ANY WARRANTY; without even the implied warranty of
   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
   GNU General Public License for more details.

   You should have received a copy of the GNU General Public License
   along with this program; if not, write to the Free Software Foundation,
   Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA.  */

#ifndef _JAVAVERSION_H
#define _JAVAVERSION_H


#ifdef __cplusplus
extern "C" {
#endif


/* Return information about the Java version used by execute_java_class().
   This is the value of System.getProperty("java.specification.version").
   Some possible values are: 1.1, 1.2, 1.3, 1.4, 1.5, 1.6.  Return NULL if
   the Java version cannot be determined.  */
extern char * javaexec_version (void);


#ifdef __cplusplus
}
#endif


#endif /* _JAVAVERSION_H */
============================ lib/javaversion.c ===========================
/* Determine the Java version supported by javaexec.
   Copyright (C) 2006 Free Software Foundation, Inc.
   Written by Bruno Haible <address@hidden>, 2006.

   This program is free software; you can redistribute it and/or modify
   it under the terms of the GNU General Public License as published by
   the Free Software Foundation; either version 2, or (at your option)
   any later version.

   This program is distributed in the hope that it will be useful,
   but WITHOUT ANY WARRANTY; without even the implied warranty of
   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
   GNU General Public License for more details.

   You should have received a copy of the GNU General Public License
   along with this program; if not, write to the Free Software Foundation,
   Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA.  */

#ifdef HAVE_CONFIG_H
# include <config.h>
#endif

/* Specification.  */
#include "javaversion.h"

#include <errno.h>
#include <stdbool.h>
#include <stdio.h>

#if ENABLE_RELOCATABLE
# include "relocatable.h"
#else
# define relocate(pathname) (pathname)
#endif

#include "javaexec.h"
#include "pipe.h"
#include "wait-process.h"
#include "error.h"
#include "getline.h"
#include "gettext.h"

#define _(str) gettext (str)


struct locals
{
  /* OUT */
  char *line;
};

static bool
execute_and_read_line (const char *progname,
                       const char *prog_path, char **prog_argv,
                       void *private_data)
{
  struct locals *l = (struct locals *) private_data;
  pid_t child;
  int fd[1];
  FILE *fp;
  char *line;
  size_t linesize;
  size_t linelen;
  int exitstatus;

  /* Open a pipe to the JVM.  */
  child = create_pipe_in (progname, prog_path, prog_argv, DEV_NULL, false,
                          true, false, fd);

  if (child == -1)
    return false;

  /* Retrieve its result.  */
  fp = fdopen (fd[0], "r");
  if (fp == NULL)
    {
      error (0, errno, _("fdopen() failed"));
      return false;
    }

  line = NULL; linesize = 0;
  linelen = getline (&line, &linesize, fp);
  if (linelen == (size_t)(-1))
    {
      error (0, 0, _("%s subprocess I/O error"), progname);
      return false;
    }
  if (linelen > 0 && line[linelen - 1] == '\n')
    line[linelen - 1] = '\0';

  fclose (fp);

  /* Remove zombie process from process list, and retrieve exit status.  */
  exitstatus = wait_subprocess (child, progname, true, false, true, false);
  if (exitstatus != 0)
    {
      free (line);
      return false;
    }

  l->line = line;
  return false;
}

char *
javaexec_version (void)
{
  const char *class_name = "javaversion";
  const char *pkgdatadir = relocate (PKGDATADIR);
  const char *args[1];
  struct locals locals;

  args[0] = NULL;
  locals.line = NULL;
  execute_java_class (class_name, &pkgdatadir, 1, true, NULL, args,
                      false, false, execute_and_read_line, &locals);

  return locals.line;
}
============================ lib/javaversion.java ===========================
/* Show the Java version.
 * Copyright (C) 2006 Free Software Foundation, Inc.
 *
 * This program is free software; you can redistribute it and/or modify
 * it under the terms of the GNU General Public License as published by
 * the Free Software Foundation; either version 2, or (at your option)
 * any later version.
 *
 * This program is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * GNU General Public License for more details.
 *
 * You should have received a copy of the GNU General Public License
 * along with this program; if not, write to the Free Software Foundation,
 * Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA.
 */

/**
 * This program shows the Java version.
 *
 * This program _must_ be compiled with
 *   javac -d . -target 1.1 javaversion.java
 * since its purpose is to show the version of _any_ Java implementation.
 *
 * @author Bruno Haible
 */
public class javaversion {
  public static void main (String[] args) {
    System.out.println(System.getProperty("java.specification.version"));
  }
}



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