forcely add UV_HANDLE_READABLE on pipe_t

* in order to detect peer close on O_WRONLY pipe_t
* partially reverted d8fe153
* refs libuv/libuv#2058
* refs MagicStack#317
* fixes MagicStack#311, fixes MagicStack#312

tests/test_pipes.py

@@ -43,6 +43,7 @@ def connection_lost(self, exc):
 
 class MyWritePipeProto(asyncio.BaseProtocol):
     done = None
+    paused = False
 
     def __init__(self, loop=None):
         self.state = 'INITIAL'
@@ -61,6 +62,12 @@ def connection_lost(self, exc):
         if self.done:
             self.done.set_result(None)
 
+    def pause_writing(self):
+        self.paused = True
+
+    def resume_writing(self):
+        self.paused = False
+
 
 class _BasePipeTest:
     def test_read_pipe(self):
@@ -241,6 +248,29 @@ def reader(data):
         self.loop.run_until_complete(proto.done)
         self.assertEqual('CLOSED', proto.state)
 
+    def test_write_buffer_full(self):
+        rpipe, wpipe = os.pipe()
+        pipeobj = io.open(wpipe, 'wb', 1024)
+
+        proto = MyWritePipeProto(loop=self.loop)
+        connect = self.loop.connect_write_pipe(lambda: proto, pipeobj)
+        transport, p = self.loop.run_until_complete(connect)
+        self.assertIs(p, proto)
+        self.assertIs(transport, proto.transport)
+        self.assertEqual('CONNECTED', proto.state)
+
+        for i in range(32):
+            transport.write(b'x' * 32768)
+            if proto.paused:
+                transport.write(b'x' * 32768)
+                break
+        else:
+            self.fail("Didn't reach a full buffer")
+
+        os.close(rpipe)
+        self.loop.run_until_complete(asyncio.wait_for(proto.done, 1))
+        self.assertEqual('CLOSED', proto.state)
+
 
 class Test_UV_Pipes(_BasePipeTest, tb.UVTestCase):
     pass

uvloop/handles/pipe.pxd

@@ -28,10 +28,6 @@ cdef class ReadUnixTransport(UVStream):
 
 cdef class WriteUnixTransport(UVStream):
 
-    cdef:
-        uv.uv_poll_t disconnect_listener
-        bint disconnect_listener_inited
-
     @staticmethod
     cdef WriteUnixTransport new(Loop loop, object protocol, Server server,
                                 object waiter)

uvloop/handles/pipe.pyx

@@ -12,6 +12,9 @@ cdef __pipe_init_uv_handle(UVStream handle, Loop loop):
     err = uv.uv_pipe_init(handle._loop.uvloop,
                           <uv.uv_pipe_t*>handle._handle,
                           0)
+    # UV_HANDLE_READABLE allows calling uv_read_start() on this pipe
+    # even if it is O_WRONLY, see also #317, libuv/libuv#2058
+    handle._handle.flags |= uv.UV_INTERNAL_HANDLE_READABLE
     if err < 0:
         handle._abort_init()
         raise convert_error(err)
@@ -147,10 +150,6 @@ cdef class ReadUnixTransport(UVStream):
 @cython.no_gc_clear
 cdef class WriteUnixTransport(UVStream):
 
-    def __cinit__(self):
-        self.disconnect_listener_inited = False
-        self.disconnect_listener.data = NULL
-
     @staticmethod
     cdef WriteUnixTransport new(Loop loop, object protocol, Server server,
                                 object waiter):
@@ -167,46 +166,6 @@ cdef class WriteUnixTransport(UVStream):
         __pipe_init_uv_handle(<UVStream>handle, loop)
         return handle
 
-    cdef _start_reading(self):
-        # A custom implementation for monitoring for EOF:
-        # libuv since v1.23.1 prohibits using uv_read_start on
-        # write-only FDs, so we use a throw-away uv_poll_t handle
-        # for that purpose, as suggested in
-        # https://github.com/libuv/libuv/issues/2058.
-
-        cdef int err
-
-        if not self.disconnect_listener_inited:
-            err = uv.uv_poll_init(self._loop.uvloop,
-                                  &self.disconnect_listener,
-                                  self._fileno())
-            if err < 0:
-                raise convert_error(err)
-            self.disconnect_listener.data = <void*>self
-            self.disconnect_listener_inited = True
-
-        err = uv.uv_poll_start(&self.disconnect_listener,
-                               uv.UV_READABLE | uv.UV_DISCONNECT,
-                               __on_write_pipe_poll_event)
-        if err < 0:
-            raise convert_error(err)
-
-    cdef _stop_reading(self):
-        cdef int err
-        if not self.disconnect_listener_inited:
-            return
-        err = uv.uv_poll_stop(&self.disconnect_listener)
-        if err < 0:
-            raise convert_error(err)
-
-    cdef _close(self):
-        if self.disconnect_listener_inited:
-            self.disconnect_listener.data = NULL
-            uv.uv_close(<uv.uv_handle_t *>(&self.disconnect_listener), NULL)
-            self.disconnect_listener_inited = False
-
-        UVStream._close(self)
-
     cdef _new_socket(self):
         return __pipe_get_socket(<UVSocketHandle>self)
 
@@ -220,25 +179,6 @@ cdef class WriteUnixTransport(UVStream):
         raise NotImplementedError
 
 
-cdef void __on_write_pipe_poll_event(uv.uv_poll_t* handle,
-                                     int status, int events) with gil:
-    cdef WriteUnixTransport tr
-
-    if handle.data is NULL:
-        return
-
-    tr = <WriteUnixTransport>handle.data
-    if tr._closed:
-        return
-
-    if events & uv.UV_DISCONNECT:
-        try:
-            tr._stop_reading()
-            tr._on_eof()
-        except BaseException as ex:
-            tr._fatal_error(ex, False)
-
-
 cdef class _PipeConnectRequest(UVRequest):
     cdef:
         UnixTransport transport

uvloop/includes/uv.pxd

@@ -3,6 +3,15 @@ from posix.types cimport gid_t, uid_t
 
 from . cimport system
 
+# This is an internal enum UV_HANDLE_READABLE from uv-common.h, used only by
+# handles/pipe.pyx to temporarily workaround a libuv issue libuv/libuv#2058,
+# before there is a proper fix in libuv. In short, libuv disallowed feeding a
+# write-only pipe to uv_read_start(), which was needed by uvloop to detect a
+# broken pipe without having to send anything on the write-only end. We're
+# setting UV_HANDLE_READABLE on pipe_t to workaround this limitation
+# temporarily, please see also #317.
+cdef enum:
+    UV_INTERNAL_HANDLE_READABLE = 0x00004000
 
 cdef extern from "uv.h" nogil:
     cdef int UV_TCP_IPV6ONLY
@@ -82,6 +91,7 @@ cdef extern from "uv.h" nogil:
     ctypedef struct uv_handle_t:
         void* data
         uv_loop_t* loop
+        unsigned int flags
         # ...
 
     ctypedef struct uv_idle_t: