# hgweb/wsgicgi.py - CGI->WSGI translator

#

# Copyright 2006 Eric Hopper <hopper@omnifarious.org>

#

# This software may be used and distributed according to the terms of the

# GNU General Public License version 2 or any later version.

#

# This was originally copied from the public domain code at

# http://www.python.org/dev/peps/pep-0333/#the-server-gateway-side

import os, sys

from mercurial import util

def launch(application):

    util.set_binary(sys.stdin)

    util.set_binary(sys.stdout)

    environ = dict(os.environ.iteritems())

    environ.setdefault('PATH_INFO', '')

    if environ.get('SERVER_SOFTWARE', '').startswith('Microsoft-IIS'):

        # IIS includes script_name in path_info

        scriptname = environ['SCRIPT_NAME']

        if environ['PATH_INFO'].startswith(scriptname):

            environ['PATH_INFO'] = environ['PATH_INFO'][len(scriptname):]

    environ['wsgi.input'] = sys.stdin

    environ['wsgi.errors'] = sys.stderr

    environ['wsgi.version'] = (1, 0)

    environ['wsgi.multithread'] = False

    environ['wsgi.multiprocess'] = True

    environ['wsgi.run_once'] = True

    if environ.get('HTTPS', 'off').lower() in ('on', '1', 'yes'):

        environ['wsgi.url_scheme'] = 'https'

    else:

        environ['wsgi.url_scheme'] = 'http'

    headers_set = []

    headers_sent = []

    out = sys.stdout

    def write(data):

        if not headers_set:

            raise AssertionError("write() before start_response()")

        elif not headers_sent:

            # Before the first output, send the stored headers

            status, response_headers = headers_sent[:] = headers_set

            out.write('Status: %s\r\n' % status)

            for header in response_headers:

                out.write('%s: %s\r\n' % header)

            out.write('\r\n')

        out.write(data)

        out.flush()

    def start_response(status, response_headers, exc_info=None):

        if exc_info:

            try:

                if headers_sent:

                    # Re-raise original exception if headers sent

                    raise exc_info[0](exc_info[1], exc_info[2])

            finally:

                exc_info = None     # avoid dangling circular ref

        elif headers_set:

            raise AssertionError("Headers already set!")

        headers_set[:] = [status, response_headers]

        return write

    content = application(environ, start_response)

    try:

        for chunk in content:

            write(chunk)

    finally:

        if hasattr(content, 'close'):

            content.close()