#!/usr/bin/env python
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"""Manage TCP ports for unit tests; started by run_tests.py"""

import argparse
import BaseHTTPServer
import hashlib
import os
import socket
import sys
import time

argp = argparse.ArgumentParser(description='Server for httpcli_test')
argp.add_argument('-p', '--port', default=12345, type=int)
args = argp.parse_args()

print 'port server running on port %d' % args.port

pool = []
in_use = {}

with open(sys.argv[0]) as f:
  _MY_VERSION = hashlib.sha1(f.read()).hexdigest()


def refill_pool():
  """Scan for ports not marked for being in use"""
  for i in range(10000, 65000):
    if len(pool) > 100: break
    if i in in_use:
      age = time.time() - in_use[i]
      if age < 600:
        continue
      del in_use[i]
    s = socket.socket(socket.AF_INET, socket.SOCK_STREAM)
    try:
      s.bind(('localhost', i))
      pool.append(i)
    except:
      pass # we really don't care about failures
    finally:
      s.close()


def allocate_port():
  global pool
  global in_use
  if not pool:
    refill_pool()
  port = pool[0]
  pool = pool[1:]
  in_use[port] = time.time()
  return port


class Handler(BaseHTTPServer.BaseHTTPRequestHandler):

  def do_GET(self):
    if self.path == '/get':
      # allocate a new port, it will stay bound for ten minutes and until
      # it's unused
      self.send_response(200)
      self.send_header('Content-Type', 'text/plain')
      self.end_headers()
      p = allocate_port()
      self.log_message('allocated port %d' % p)
      self.wfile.write('%d' % p)
    elif self.path == '/version_and_pid':
      # fetch a version string and the current process pid
      self.send_response(200)
      self.send_header('Content-Type', 'text/plain')
      self.end_headers()
      self.wfile.write('%s+%d' % (_MY_VERSION, os.getpid()))


BaseHTTPServer.HTTPServer(('', args.port), Handler).serve_forever()