Completely rewrite signal handling.

Instead of using libuv signal handlers, we now simply use
signal.set_wakeup_fd function (exactly the same approach as
in asyncio).  As the result, the new code is *much* simpler,
and uvloop programs don't mess with low-level signal
processing APIs.

Author: 1st1

uvloop/_noop.py

@@ -0,0 +1,3 @@
+def noop():
+    """Empty function to invoke CPython ceval loop."""
+    return

uvloop/cbhandles.pyx

@@ -30,7 +30,6 @@ cdef class Handle:
         cdef:
             int cb_type
             object callback
-            bint old_exec_py_code
 
         if self.cancelled:
             return
@@ -40,12 +39,6 @@ cdef class Handle:
         Py_INCREF(self)   # Since _run is a cdef and there's no BoundMethod,
                           # we guard 'self' manually (since the callback
                           # might cause GC of the handle.)
-        old_exec_py_code = self.loop._executing_py_code
-        # old_exec_py_code might be 0 -- that means that this
-        # handle is run by libuv callback or something
-        # and it can be 1 -- that means that we're calling it
-        # from a UVHandle (for instance UVIdle) callback.
-        self.loop._executing_py_code = 1
         try:
             if cb_type == 1:
                 callback = self.arg1
@@ -91,7 +84,6 @@ cdef class Handle:
             self.loop.call_exception_handler(context)
 
         finally:
-            self.loop._executing_py_code = old_exec_py_code
             Py_DECREF(self)
 
     cdef _cancel(self):
@@ -177,9 +169,6 @@ cdef class TimerHandle:
             self.timer = None  # let it die asap
 
     cdef _run(self):
-        cdef:
-            bint old_exec_py_code
-
         if self.closed == 1:
             return
 
@@ -189,11 +178,6 @@ cdef class TimerHandle:
 
         Py_INCREF(self)  # Since _run is a cdef and there's no BoundMethod,
                          # we guard 'self' manually.
-        old_exec_py_code = self.loop._executing_py_code
-        IF DEBUG:
-            if old_exec_py_code == 1:
-                raise RuntimeError('Python exec-mode before TimerHandle._run')
-        self.loop._executing_py_code = 1
         if self.loop._debug:
             started = time_monotonic()
         try:
@@ -220,7 +204,6 @@ cdef class TimerHandle:
                         'Executing %r took %.3f seconds',
                         self, delta)
         finally:
-            self.loop._executing_py_code = old_exec_py_code
             Py_DECREF(self)
 
     # Public API

uvloop/handles/signal.pxd

@@ -832,13 +832,9 @@ cdef void __uv_stream_on_read(uv.uv_stream_t* stream,
 
     cdef:
         Loop loop = <Loop>stream.loop.data
-        bint old_exec_py_code
 
-    old_exec_py_code = loop._executing_py_code
-    loop._executing_py_code = 1
     # Don't need try-finally, __uv_stream_on_read_impl is void
     __uv_stream_on_read_impl(stream, nread, buf)
-    loop._executing_py_code = old_exec_py_code
 
 
 cdef void __uv_stream_on_write(uv.uv_write_t* req, int status) with gil:
@@ -852,10 +848,6 @@ cdef void __uv_stream_on_write(uv.uv_write_t* req, int status) with gil:
 
     cdef:
         Loop loop = <UVStream>(<_StreamWriteContext> req.data).stream._loop
-        bint old_exec_py_code
 
-    old_exec_py_code = loop._executing_py_code
-    loop._executing_py_code = 1
     # Don't need try-finally, __uv_stream_on_write_impl is void
     __uv_stream_on_write_impl(req, status)
-    loop._executing_py_code = old_exec_py_code

uvloop/handles/signal.pyx

@@ -2,6 +2,7 @@
 import asyncio
 import collections
 import concurrent.futures
+import errno
 import functools
 import gc
 import inspect

uvloop/handles/stream.pyx

@@ -3,6 +3,7 @@ import asyncio, asyncio.log, asyncio.base_events, \
        asyncio.futures
 import collections
 import concurrent.futures
+import errno
 import functools
 import gc
 import inspect
@@ -43,6 +44,8 @@ cdef col_Counter = collections.Counter
 cdef cc_ThreadPoolExecutor = concurrent.futures.ThreadPoolExecutor
 cdef cc_Future = concurrent.futures.Future
 
+cdef errno_EINVAL = errno.EINVAL
+
 cdef ft_partial = functools.partial
 
 cdef gc_disable = gc.disable
@@ -57,6 +60,7 @@ cdef socket_gaierror = socket.gaierror
 cdef socket_error = socket.error
 cdef socket_timeout = socket.timeout
 cdef socket_socket = socket.socket
+cdef socket_socketpair = socket.socketpair
 cdef socket_getservbyname = socket.getservbyname
 
 cdef int socket_EAI_ADDRFAMILY = getattr(socket, 'EAI_ADDRFAMILY', -1)
@@ -110,6 +114,10 @@ cdef int subprocess_DEVNULL = subprocess.DEVNULL
 cdef subprocess_SubprocessError = subprocess.SubprocessError
 
 cdef int signal_NSIG = std_signal.NSIG
+cdef signal_signal = std_signal.signal
+cdef signal_set_wakeup_fd = std_signal.set_wakeup_fd
+cdef signal_default_int_handler = std_signal.default_int_handler
+cdef signal_SIG_DFL = std_signal.SIG_DFL
 
 cdef time_sleep = time.sleep
 cdef time_monotonic = time.monotonic
@@ -122,7 +130,7 @@ cdef warnings_warn = warnings.warn
 
 # Cython doesn't clean-up imported objects properly in Py3 mode,
 # so we delete refs to all modules manually (except sys)
-del asyncio, concurrent, collections
+del asyncio, concurrent, collections, errno
 del functools, inspect, itertools, socket, os, threading
 del std_signal, subprocess, ssl
 del time, traceback, warnings

uvloop/includes/__init__.py

@@ -21,7 +21,6 @@ cdef class UVHandle
 
 cdef class UVAsync(UVHandle)
 cdef class UVTimer(UVHandle)
-cdef class UVSignal(UVHandle)
 cdef class UVIdle(UVHandle)
 
 ctypedef object (*method_t)(object)
@@ -45,11 +44,6 @@ cdef class Loop:
 
         long _thread_id
         bint _thread_is_main
-        bint _sigint_check
-
-        SignalsStack py_signals
-        SignalsStack uv_signals
-        bint _executing_py_code
 
         object _task_factory
         object _exception_handler
@@ -58,19 +52,18 @@ cdef class Loop:
         set _queued_streams
         Py_ssize_t _ready_len
 
+        dict _signal_handlers
+        object _ssock
+        object _csock
+
         set _timers
         dict _polls
 
-        dict _signal_handlers
-        bint _custom_sigint
-
         UVProcess active_process_handler
 
         UVAsync handler_async
         UVIdle handler_idle
         UVCheck handler_check__exec_writes
-        UVSignal handler_sigint
-        UVSignal handler_sighup
 
         object _last_error
 
@@ -121,10 +114,6 @@ cdef class Loop:
 
     cdef _on_wake(self)
     cdef _on_idle(self)
-    cdef _on_sigint(self)
-    cdef _on_sighup(self)
-
-    cdef _check_sigint(self)
 
     cdef __run(self, uv.uv_run_mode)
     cdef _run(self, uv.uv_run_mode)
@@ -177,6 +166,12 @@ cdef class Loop:
 
     cdef _sock_set_reuseport(self, int fd)
 
+    cdef _setup_signals(self)
+    cdef _shutdown_signals(self)
+    cdef _handle_signal(self, sig)
+    cdef _read_from_self(self)
+    cdef _process_self_data(self, data)
+
     cdef _set_coroutine_wrapper(self, bint enabled)
 
 
@@ -187,7 +182,6 @@ include "handles/async_.pxd"
 include "handles/idle.pxd"
 include "handles/check.pxd"
 include "handles/timer.pxd"
-include "handles/signal.pxd"
 include "handles/poll.pxd"
 include "handles/basetransport.pxd"
 include "handles/stream.pxd"
@@ -201,5 +195,3 @@ include "request.pxd"
 include "handles/udp.pxd"
 
 include "server.pxd"
-
-include "os_signal.pxd"