# ====================================================================
 # The Apache Software License, Version 1.1
 #
 # Copyright (c) 2000-2002 The Apache Software Foundation.  All rights
 # reserved.
 #
 # Redistribution and use in source and binary forms, with or without
 # modification, are permitted provided that the following conditions
 # are met:
 #
 # 1. Redistributions of source code must retain the above copyright
 #    notice, this list of conditions and the following disclaimer.
 #
 # 2. Redistributions in binary form must reproduce the above copyright
 #    notice, this list of conditions and the following disclaimer in
 #    the documentation and/or other materials provided with the
 #    distribution.
 #
 # 3. The end-user documentation included with the redistribution,
 #    if any, must include the following acknowledgment:
 #       "This product includes software developed by the
 #        Apache Software Foundation (http://www.apache.org/)."
 #    Alternately, this acknowledgment may appear in the software itself,
 #    if and wherever such third-party acknowledgments normally appear.
 #
 # 4. The names "Apache" and "Apache Software Foundation" must
 #    not be used to endorse or promote products derived from this
 #    software without prior written permission. For written
 #    permission, please contact apache@apache.org.
 #
 # 5. Products derived from this software may not be called "Apache",
 #    "mod_python", or "modpython", nor may these terms appear in their
 #    name, without prior written permission of the Apache Software
 #    Foundation.
 #
 # THIS SOFTWARE IS PROVIDED ``AS IS'' AND ANY EXPRESSED OR IMPLIED
 # WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
 # OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
 # DISCLAIMED.  IN NO EVENT SHALL THE APACHE SOFTWARE FOUNDATION OR
 # ITS CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
 # SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
 # LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF
 # USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND
 # ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY,
 # OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT
 # OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
 # SUCH DAMAGE.
 # ====================================================================
 #
 # This software consists of voluntary contributions made by many
 # individuals on behalf of the Apache Software Foundation.  For more
 # information on the Apache Software Foundation, please see
 # <http://www.apache.org/>.
 #
 # Originally developed by Gregory Trubetskoy.
 #
 # $Id: cgihandler.py,v 1.12 2002/12/28 03:43:40 grisha Exp $

import apache
import imp
import os
import sys

# if threads are not available
# create a functionless lock object
try:
    import threading
    _lock = threading.Lock()
except (ImportError, AttributeError):
    class DummyLock:
        def acquire(self):
            pass
        def release(self):
            pass
    _lock = DummyLock()

# the next statement  deserves some explaining.
# it seems that the standard os.environ object looses
# memory if the environment is manipulated frequently. Since for
# CGI you have to rebuild it for every request, your httpd will
# grow rather fast. I am not exactly sure why it happens and if there
# is a more sensible remedy, but this seems to work OK.
os.environ = {}

original = sys.modules.keys()

# find out the standard library location
stdlib, x = os.path.split(os.__file__)

def handler(req):

    ### if you don't need indirect modules reloaded, comment out
    ### code unitl ### end

    # if there are any new modules since the import of this module,
    # delete them.
    for m in sys.modules.keys():
        if m not in original:
            # unless they are part of standard library
            mod = sys.modules[m]
            if hasattr(mod, "__file__"):
                path, x = os.path.split(mod.__file__)
                if path != stdlib:
                    del sys.modules[m]
    ### end

    # get the filename of the script
    if req.subprocess_env.has_key("script_filename"):
        dir, file = os.path.split(req.subprocess_env["script_filename"])
    else:
        dir, file = os.path.split(req.filename)
    module_name, ext = os.path.splitext(file)

    _lock.acquire()
    try:

        try:

            # The CGI spec requires us to set current working
            # directory to that of the script. This is not
            # thread safe, this is why we must obtain the lock.
            cwd = os.getcwd()
            os.chdir(dir)

            # simulate cgi environment
            env, si, so = apache.setup_cgi(req)

            try:
                # we do not search the pythonpath (security reasons)
                fd, path, desc = imp.find_module(module_name, [dir])
            except ImportError:
                raise apache.SERVER_RETURN, apache.HTTP_NOT_FOUND

            # this executes the module
            imp.load_module(module_name, fd, path, desc)

            return apache.OK

        finally:
            # unsimulate the cgi environment
            apache.restore_nocgi(env, si, so)
            try:
                fd.close()
            except: pass
            os.chdir(cwd)
    finally:
        _lock.release()