perlfunc.py

#!/usr/bin/env python
# -*- coding: utf-8 -*-

"""
/*  Copyright 2007, Jose Rodriguez (a.k.a. Boriel), http://www.boriel.com
**
**  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 of the License, 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 can read it at: http://www.gnu.org/copyleft/gpl.html or
**  write to the Free Software Foundation, Inc., 59 Temple Place,
**  Suite 330, Boston, MA  02111-1307  USA
*/
"""

import tempfile
import os
import sys
from subprocess import Popen, PIPE

# Python version (2, 3)
PY_VERSION = sys.version_info[0]

# Initialize types
if PY_VERSION == 3:
    unicode = str


# Dictionary containing PERL5LIB path for each function
__PERL5LIB = {}

# Default PERL include PATH
__DEFAULT_PERL5LIB = '.'


# Executes system command and captures output
def sys_exec(cmd, shell=True, env=None):
    if env is None:
        env = os.environ
    
    a = Popen(cmd, shell=shell, stdout=PIPE, stderr=PIPE, env=env)
    a.wait()          # Wait process to terminate
    if a.returncode:  # Not 0 => Error
        raise BaseException(str(a.communicate()[1]))

    return a.communicate()[0].decode('utf-8')


# Perl path
PERL = sys_exec('which perl').strip(' \t\n\r')

# Set to True to leave the tmp file (for debug)
DEBUG = False


def perlargs(*args):
    def perl_elem(x):
        if x is None:
            return 'undef'

        if isinstance(x, (str, unicode)):
            return "'%s'" % str(x).replace("'", "\\'")

        return str(x)

    def perl_vector(vec):
        sep = result = ''
        for i in vec:
            result += sep
            if isinstance(i, list):
                result += '[' + perl_vector(i) + ']'
            elif isinstance(i, dict):
                result += '{' + perl_dict(i) + '}'
            else:
                result += perl_elem(i)
            sep = ', '

        return result

    def perl_dict(vec):
        sep = result = ''
        for i, t in vec.items():
            result += sep + str(i) + ' => '
            if isinstance(t, list):
                result += '[' + perl_vector(t) + ']'
            elif isinstance(t, dict):
                result += '{' + perl_dict(t) + '}'
            else:
                result += perl_elem(t)
            sep = ', '

        return result

    sep = ''
    result = '('
    for i in args:
        result += sep
        if isinstance(i, dict):
            result += '(' + perl_dict(i) + ')'
        elif isinstance(i, list):
            result += '(' + perl_vector(i) + ')'
        else:
            result += perl_elem(i)
        sep = ', '

    result += ')'

    return result


# Decorator which allows to call a perl function from python
def perlfunc(fn):
    def new(*args):
        tmppipe, pipename = tempfile.mkstemp('.pipe', 'tmp_', '/tmp', text=True)
        os.close(tmppipe)

        tmpfile, tmpname = tempfile.mkstemp('.pl', 'tmp_', '/tmp', text=True)
        os.write(tmpfile, fn.__doc__.encode('utf-8'))  # Writes the perl code
        os.write(tmpfile, (r'''
        {
            my @rst;
            my $len;
            my $i;

            open(DAT, ">''' + pipename + '''") || die("Cannot Open File for communication");
    
            @rst = (%s%s);
            if (@rst) {
                $len = @rst;
            } else {
                $len = 0;
                print DAT 'None';
            }
    
            if ($len > 1) {
                print DAT '[';
            }
    
            for ($i = 0; $i < $len; $i++) {
                if ($i) {
                    print DAT ', ';
                }
    
                $rst[$i] =~ s/\'/\\\'/g;
                print DAT "'" . $rst[$i] . "'";
            }
    
            if ($len > 1) {
                print DAT ']';
            }

            close(DAT);
        }

        ''' % (fn.__name__, perlargs(*args))).encode('utf-8'))
        os.close(tmpfile)

        try:
            env = os.environ                            # Get OS environment vars
            env['PERL5LIB'] = __PERL5LIB[fn.__name__]  # Adds our PERL5LIB if defined
        except KeyError:
            env = os.environ
            env['PERL5LIB'] = __DEFAULT_PERL5LIB

        # Eval perl code
        result_stdout = sys_exec([PERL] + [tmpname], False, env=env)
        if DEBUG:
            print('STDOUT: ' + result_stdout)
        with open(pipename, 'rt') as pipe:
            result_str = pipe.read()

        try:
            result = eval(result_str)
        except:
            result = result_str

        # Erases tmp file
        if not DEBUG:
            os.unlink(tmpname)
            os.unlink(pipename)

        return result

    return new  # Decorated function


# Decorator which adds perl includes
def perlreq(*modules):
    def require_inc(fn):
        def new(*args):
            return fn(*args)

        new.__name__ = fn.__name__
        new.__doc__ = fn.__doc__ if fn.__doc__ is not None else ''

        for i in modules:
            if i.endswith(".pm"):
                new.__doc__ = 'use %s;\n' % i[:-3] + new.__doc__
            else:
                new.__doc__ = 'require(\'%s\');\n' % i + new.__doc__
        return new

    return require_inc

    
# Decorator which changes perl include path
def perl5lib(*paths):
    def include_fun(fn):
        global __PERL5LIB

        def new(*args):
            return fn(*args)

        new.__name__ = fn.__name__
        new.__doc__ = fn.__doc__

        try:
            PATH = __PERL5LIB[fn.__name__] + ':'
        except KeyError:  # Not defined in __PERL5LIB yet
            PATH = ''

        __PERL5LIB[fn.__name__] = PATH + ':'.join(paths)
        return new

    return include_fun