initial add evdns.pxi from pyevent trunk

--HG--
extra : transplant_source : %7CY%BF%0AC%23%B0%B3ITS%AB%F35%C1%00%1E%0C%12%9F

gevent/evdns.pxi

+cdef extern from "arpa/inet.h":
+    struct in_addr
+    char *inet_ntoa(in_addr n)
+
+cdef extern from "evdns.h":
+    ctypedef void (*evdns_handler)(int result, char t, int count, int ttl,
+                                   void *addrs, void *arg)
+
+    int evdns_init()
+    char *evdns_err_to_string(int err)
+    int evdns_resolve_ipv4(char *name, int flags, evdns_handler callback,
+                           void *arg)
+    int evdns_resolve_ipv6(char *name, int flags, evdns_handler callback,
+                           void *arg)
+    int evdns_resolve_reverse(char *ip, int flags, evdns_handler callback,
+                              void *arg)
+    int evdns_resolve_reverse_ipv6(char *ip, int flags, evdns_handler callback,
+                                   void *arg)
+    void evdns_shutdown(int fail_requests)
+
+# Result codes
+DNS_ERR_NONE		= 0
+DNS_ERR_FORMAT		= 1
+DNS_ERR_SERVERFAILED	= 2
+DNS_ERR_NOTEXIST	= 3
+DNS_ERR_NOTIMPL		= 4
+DNS_ERR_REFUSED		= 5
+DNS_ERR_TRUNCATED	= 65
+DNS_ERR_UNKNOWN		= 66
+DNS_ERR_TIMEOUT		= 67
+DNS_ERR_SHUTDOWN	= 68
+
+# Types
+DNS_IPv4_A		= 1
+DNS_PTR			= 2
+DNS_IPv6_AAAA		= 3
+
+# Flags
+DNS_QUERY_NO_SEARCH	= 1
+
+def dns_init():
+    """Initialize async DNS resolver."""
+    evdns_init()
+    #__evdns_cbargs.clear()
+
+cdef void __evdns_callback(int result, char t, int count, int ttl,
+                     void *addrs, void *arg) with gil:
+    cdef int i
+    cdef in_addr *inaddrs
+    ctx = <tuple>(arg)
+    (callback, args) = ctx
+    Py_DECREF(ctx)
+
+    if t == DNS_IPv4_A:
+        x = []
+        inaddrs = <in_addr *>addrs
+        for i from 0 <= i < count:
+            #x.append(PyString_FromStringAndSize(<char *>addrs + (i * 4), 4))
+            x.append(PyString_FromString(inet_ntoa(inaddrs[i])))
+    elif t == DNS_IPv6_AAAA:
+        x = []
+        for i from 0 <= i < count:
+            x.append(PyString_FromStringAndSize(<char *>addrs + (i * 16), 16))
+    elif t == DNS_PTR and count == 1: # only 1 PTR possible
+        x = PyString_FromString((<char **>addrs)[0])
+    else:
+        x = None
+    try:
+        callback(result, t, ttl, x, args)
+    except:
+        # JJJ commented this out and added trackback print
+        #__event_abort()
+        traceback.print_exc()
+
+    
+def dns_resolve_ipv4(char *name, int flags, callback, *args):
+    """Lookup an A record for a given name.
+
+    Arguments:
+
+    name     -- DNS hostname
+    flags    -- either 0 or DNS_QUERY_NO_SEARCH
+    callback -- callback with (result, type, ttl, addrs, *args) prototype
+    args     -- option callback arguments
+    """
+    cdef long long i
+    t = (callback, args)
+    Py_INCREF(t)
+    evdns_resolve_ipv4(name, flags, __evdns_callback, <void *>t)
+
+def dns_resolve_ipv6(char *name, int flags, callback, *args):
+    """Lookup an AAAA record for a given name.
+
+    Arguments:
+
+    name     -- DNS hostname
+    flags    -- either 0 or DNS_QUERY_NO_SEARCH
+    callback -- callback with (result, type, ttl, addrs, *args) prototype
+    args     -- option callback arguments
+    """
+    cdef long long i
+    t = (callback, args)
+    Py_INCREF(t)
+    evdns_resolve_ipv6(name, flags, __evdns_callback, <void *>t)
+
+def dns_resolve_reverse(char *ip, int flags, callback, *args):
+    """Lookup a PTR record for a given IPv4 address.
+
+    Arguments:
+
+    name     -- IPv4 address (as 4-byte binary string)
+    flags    -- either 0 or DNS_QUERY_NO_SEARCH
+    callback -- callback with (result, type, ttl, addrs, *args) prototype
+    args     -- option callback arguments
+    """
+    cdef long long i
+    t = (callback, args)
+    Py_INCREF(t)
+    evdns_resolve_reverse(ip, flags, __evdns_callback, <void *>t)
+
+def dns_resolve_reverse_ipv6(char *ip, int flags, callback, *args):
+    """Lookup a PTR record for a given IPv6 address.
+
+    Arguments:
+
+    name     -- IPv6 address (as 16-byte binary string)
+    flags    -- either 0 or DNS_QUERY_NO_SEARCH
+    callback -- callback with (result, type, ttl, addrs, *args) prototype
+    args     -- option callback arguments
+    """
+    cdef long long i
+    t = (callback, args)
+    Py_INCREF(t)
+    evdns_resolve_reverse(ip, flags, __evdns_callback, <void *>t)
+
+def dns_shutdown(int fail_requests=0):
+    """Shutdown the async DNS resolver and terminate all active requests."""
+    evdns_shutdown(fail_requests)
+