1 files changed, 71 insertions, 0 deletions
diff --git a/python/gevent/resolver_thread.py b/python/gevent/resolver_thread.py
new file mode 100644
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--- /dev/null
+++ b/python/gevent/resolver_thread.py
@@ -0,0 +1,71 @@
+# Copyright (c) 2012-2015 Denis Bilenko. See LICENSE for details.
+"""
+Native thread-based hostname resolver.
+"""
+import _socket
+from gevent._compat import text_type
+from gevent.hub import get_hub
+
+
+__all__ = ['Resolver']
+
+
+# trigger import of encodings.idna to avoid https://github.com/gevent/gevent/issues/349
+text_type('foo').encode('idna')
+
+
+class Resolver(object):
+    """
+    Implementation of the resolver API using native threads and native resolution
+    functions.
+
+    Using the native resolution mechanisms ensures the highest
+    compatibility with what a non-gevent program would return
+    including good support for platform specific configuration
+    mechanisms. The use of native (non-greenlet) threads ensures that
+    a caller doesn't block other greenlets.
+
+    This implementation also has the benefit of being very simple in comparison to
+    :class:`gevent.resolver_ares.Resolver`.
+
+    .. tip::
+
+        Most users find this resolver to be quite reliable in a
+        properly monkey-patched environment. However, there have been
+        some reports of long delays, slow performance or even hangs,
+        particularly in long-lived programs that make many, many DNS
+        requests. If you suspect that may be happening to you, try the
+        ares resolver (and submit a bug report).
+    """
+    def __init__(self, hub=None):
+        if hub is None:
+            hub = get_hub()
+        self.pool = hub.threadpool
+        if _socket.gaierror not in hub.NOT_ERROR:
+            # Do not cause lookup failures to get printed by the default
+            # error handler. This can be very noisy.
+            hub.NOT_ERROR += (_socket.gaierror, _socket.herror)
+
+    def __repr__(self):
+        return '<gevent.resolver_thread.Resolver at 0x%x pool=%r>' % (id(self), self.pool)
+
+    def close(self):
+        pass
+
+    # from briefly reading socketmodule.c, it seems that all of the functions
+    # below are thread-safe in Python, even if they are not thread-safe in C.
+
+    def gethostbyname(self, *args):
+        return self.pool.apply(_socket.gethostbyname, args)
+
+    def gethostbyname_ex(self, *args):
+        return self.pool.apply(_socket.gethostbyname_ex, args)
+
+    def getaddrinfo(self, *args, **kwargs):
+        return self.pool.apply(_socket.getaddrinfo, args, kwargs)
+
+    def gethostbyaddr(self, *args, **kwargs):
+        return self.pool.apply(_socket.gethostbyaddr, args, kwargs)
+
+    def getnameinfo(self, *args, **kwargs):
+        return self.pool.apply(_socket.getnameinfo, args, kwargs)