# 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

from ..pycompat import getattr

from .. import pycompat

from ..utils import procutil

from . import common

def launch(application):

    procutil.setbinary(procutil.stdin)

    procutil.setbinary(procutil.stdout)

    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) :]

    stdin = procutil.stdin

    if environ.get('HTTP_EXPECT', '').lower() == '100-continue':

        stdin = common.continuereader(stdin, procutil.stdout.write)

    environ['wsgi.input'] = stdin

    environ['wsgi.errors'] = procutil.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 = procutil.stdout

    def write(data):

        if not headers_set:

            raise AssertionError(b"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(b'Status: %s\r\n' % pycompat.bytesurl(status))

            for hk, hv in response_headers:

                out.write(

                    b'%s: %s\r\n'

                    % (pycompat.bytesurl(hk), pycompat.bytesurl(hv))

                )

            out.write(b'\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:

                del exc_info  # avoid dangling circular ref

        elif headers_set:

            raise AssertionError(b"Headers already set!")

        headers_set[:] = [status, response_headers]

        return write

    content = application(environ, start_response)

    try:

        for chunk in content:

            write(chunk)

        if not headers_sent:

            write(b'')  # send headers now if body was empty

    finally:

        getattr(content, 'close', lambda: None)()