## Amazon S3 manager
 ## Author: Michal Ludvig <michal@logix.cz>
 ##         http://www.logix.cz/michal
 ## License: GPL Version 2
 ## Copyright: TGRMN Software and contributors
 

 import httplib
 from urlparse import urlparse
 from threading import Semaphore
 from logging import debug, info, warning, error
 
 from Config import Config

 from Exceptions import ParameterError

 
 __all__ = [ "ConnMan" ]
 
 class http_connection(object):

     def __init__(self, id, hostname, ssl, cfg):

         self.hostname = hostname
         self.ssl = ssl
         self.id = id
         self.counter = 0

         if cfg.proxy_host != "":
             self.c = httplib.HTTPConnection(cfg.proxy_host, cfg.proxy_port)
         elif not ssl:

             self.c = httplib.HTTPConnection(hostname)
         else:
             self.c = httplib.HTTPSConnection(hostname)
 
 class ConnMan(object):
     conn_pool_sem = Semaphore()
     conn_pool = {}
     conn_max_counter = 800    ## AWS closes connection after some ~90 requests
 
     @staticmethod
     def get(hostname, ssl = None):

         cfg = Config()

         if ssl == None:

             ssl = cfg.use_https

         conn = None

         if cfg.proxy_host != "":
             if ssl:
                 raise ParameterError("use_ssl=True can't be used with proxy")
             conn_id = "proxy://%s:%s" % (cfg.proxy_host, cfg.proxy_port)
         else:
             conn_id = "http%s://%s" % (ssl and "s" or "", hostname)

         ConnMan.conn_pool_sem.acquire()
         if not ConnMan.conn_pool.has_key(conn_id):
             ConnMan.conn_pool[conn_id] = []
         if len(ConnMan.conn_pool[conn_id]):
             conn = ConnMan.conn_pool[conn_id].pop()
             debug("ConnMan.get(): re-using connection: %s#%d" % (conn.id, conn.counter))
         ConnMan.conn_pool_sem.release()
         if not conn:
             debug("ConnMan.get(): creating new connection: %s" % conn_id)

             conn = http_connection(conn_id, hostname, ssl, cfg)

             conn.c.connect()
         conn.counter += 1
         return conn
 
     @staticmethod
     def put(conn):

         if conn.id.startswith("proxy://"):
             conn.c.close()
             debug("ConnMan.put(): closing proxy connection (keep-alive not yet supported)")
             return
 

         if conn.counter >= ConnMan.conn_max_counter:
             conn.c.close()
             debug("ConnMan.put(): closing over-used connection")
             return
 
         ConnMan.conn_pool_sem.acquire()
         ConnMan.conn_pool[conn.id].append(conn)
         ConnMan.conn_pool_sem.release()
         debug("ConnMan.put(): connection put back to pool (%s#%d)" % (conn.id, conn.counter))