tests/tinyproxy.py

dirstate: when calling rebuild(), avoid some N^2 codepaths

I had a user repo with 200k files in it. Calling `hg debugrebuilddirstate` took
tens of minutes (I didn't wait for it). In that situation,
changedfiles==allfiles, and both are lists. This meant that we had to run an
average of 100k comparisons, for each of 200k files, just to check whether a
file needed to have normallookup called (it always did), or drop.

While it's probably not a huge issue, in my very awkward synthetic benchmark I
wrote (not using a benchmark library or anything), I was seeing some slowdowns
for small-changedfiles and very-large-allfiles invocations, with an inflection
somewhere around 10 items in changedfiles (regardless of the size of allfiles);
above 10 items in changedfiles, the new code appears to always be faster. For
the case of 50k files in changedfiles and the same items in allfiles, I'm seeing
differences of 15s of just running comparisons vs. 0.003793s. I haven't bothered
to run a comparison of 200k items in changedfiles and allfiles. :)

Differential Revision: https://phab.mercurial-scm.org/D7665

#!/usr/bin/env python

from __future__ import absolute_import, print_function

__doc__ = """Tiny HTTP Proxy.

This module implements GET, HEAD, POST, PUT and DELETE methods
on BaseHTTPServer, and behaves as an HTTP proxy.  The CONNECT
method is also implemented experimentally, but has not been
tested yet.

Any help will be greatly appreciated.           SUZUKI Hisao
"""

__version__ = "0.2.1"

import optparse
import os
import select
import socket
import sys

from mercurial import (
    pycompat,
    util,
)

httpserver = util.httpserver
socketserver = util.socketserver
urlreq = util.urlreq

if os.environ.get('HGIPV6', '0') == '1':
    family = socket.AF_INET6
else:
    family = socket.AF_INET


class ProxyHandler(httpserver.basehttprequesthandler):
    __base = httpserver.basehttprequesthandler
    __base_handle = __base.handle

    server_version = "TinyHTTPProxy/" + __version__
    rbufsize = 0  # self.rfile Be unbuffered

    def handle(self):
        (ip, port) = self.client_address
        allowed = getattr(self, 'allowed_clients', None)
        if allowed is not None and ip not in allowed:
            self.raw_requestline = self.rfile.readline()
            if self.parse_request():
                self.send_error(403)
        else:
            self.__base_handle()

    def log_request(self, code='-', size='-'):
        xheaders = [h for h in self.headers.items() if h[0].startswith('x-')]
        self.log_message(
            '"%s" %s %s%s',
            self.requestline,
            str(code),
            str(size),
            ''.join([' %s:%s' % h for h in sorted(xheaders)]),
        )
        # Flush for Windows, so output isn't lost on TerminateProcess()
        sys.stdout.flush()
        sys.stderr.flush()

    def _connect_to(self, netloc, soc):
        i = netloc.find(':')
        if i >= 0:
            host_port = netloc[:i], int(netloc[i + 1 :])
        else:
            host_port = netloc, 80
        print("\t" "connect to %s:%d" % host_port)
        try:
            soc.connect(host_port)
        except socket.error as arg:
            try:
                msg = arg[1]
            except (IndexError, TypeError):
                msg = arg
            self.send_error(404, msg)
            return 0
        return 1

    def do_CONNECT(self):
        soc = socket.socket(family, socket.SOCK_STREAM)
        try:
            if self._connect_to(self.path, soc):
                self.log_request(200)
                self.wfile.write(
                    pycompat.bytestr(self.protocol_version)
                    + b" 200 Connection established\r\n"
                )
                self.wfile.write(
                    b"Proxy-agent: %s\r\n"
                    % pycompat.bytestr(self.version_string())
                )
                self.wfile.write(b"\r\n")
                self._read_write(soc, 300)
        finally:
            print("\t" "bye")
            soc.close()
            self.connection.close()

    def do_GET(self):
        (scm, netloc, path, params, query, fragment) = urlreq.urlparse(
            self.path, 'http'
        )
        if scm != 'http' or fragment or not netloc:
            self.send_error(400, "bad url %s" % self.path)
            return
        soc = socket.socket(family, socket.SOCK_STREAM)
        try:
            if self._connect_to(netloc, soc):
                self.log_request()
                url = urlreq.urlunparse(('', '', path, params, query, ''))
                soc.send(
                    b"%s %s %s\r\n"
                    % (
                        pycompat.bytestr(self.command),
                        pycompat.bytestr(url),
                        pycompat.bytestr(self.request_version),
                    )
                )
                self.headers['Connection'] = 'close'
                del self.headers['Proxy-Connection']
                for key, val in self.headers.items():
                    soc.send(
                        b"%s: %s\r\n"
                        % (pycompat.bytestr(key), pycompat.bytestr(val))
                    )
                soc.send(b"\r\n")
                self._read_write(soc)
        finally:
            print("\t" "bye")
            soc.close()
            self.connection.close()

    def _read_write(self, soc, max_idling=20):
        iw = [self.connection, soc]
        ow = []
        count = 0
        while True:
            count += 1
            (ins, _, exs) = select.select(iw, ow, iw, 3)
            if exs:
                break
            if ins:
                for i in ins:
                    if i is soc:
                        out = self.connection
                    else:
                        out = soc
                    try:
                        data = i.recv(8192)
                    except socket.error:
                        break
                    if data:
                        out.send(data)
                        count = 0
            else:
                print("\t" "idle", count)
            if count == max_idling:
                break

    do_HEAD = do_GET
    do_POST = do_GET
    do_PUT = do_GET
    do_DELETE = do_GET


class ThreadingHTTPServer(socketserver.ThreadingMixIn, httpserver.httpserver):
    def __init__(self, *args, **kwargs):
        httpserver.httpserver.__init__(self, *args, **kwargs)
        a = open("proxy.pid", "w")
        a.write(str(os.getpid()) + "\n")
        a.close()


def runserver(port=8000, bind=""):
    server_address = (bind, port)
    ProxyHandler.protocol_version = "HTTP/1.0"
    httpd = ThreadingHTTPServer(server_address, ProxyHandler)
    sa = httpd.socket.getsockname()
    print("Serving HTTP on", sa[0], "port", sa[1], "...")
    try:
        httpd.serve_forever()
    except KeyboardInterrupt:
        print("\nKeyboard interrupt received, exiting.")
        httpd.server_close()
        sys.exit(0)


if __name__ == '__main__':
    argv = sys.argv
    if argv[1:] and argv[1] in ('-h', '--help'):
        print(argv[0], "[port [allowed_client_name ...]]")
    else:
        if argv[2:]:
            allowed = []
            for name in argv[2:]:
                client = socket.gethostbyname(name)
                allowed.append(client)
                print("Accept: %s (%s)" % (client, name))
            ProxyHandler.allowed_clients = allowed
            del argv[2:]
        else:
            print("Any clients will be served...")

        parser = optparse.OptionParser()
        parser.add_option(
            '-b',
            '--bind',
            metavar='ADDRESS',
            help='Specify alternate bind address ' '[default: all interfaces]',
            default='',
        )
        (options, args) = parser.parse_args()
        port = 8000
        if len(args) == 1:
            port = int(args[0])
        runserver(port, options.bind)