libev-cffi: Use nlink_t and let the compiler fill in the definition.

Fixes #1372.

This may require a slightly stricter adherance to POSIX? It is defined by IEEE Std 1003.1 2004 (http://pubs.opengroup.org/onlinepubs/009696699/basedefs/sys/types.h.html)

CHANGES.rst

@@ -44,6 +44,10 @@
 - Avoid unbounded memory usage when creating very deep spawn trees.
   Reported in :issue:`1371` by dmrlawson.
 
+- libev-cffi: Let the compiler fill in the definition of ``nlink_t`` for
+  ``st_nlink`` in ``struct stat``, instead of trying to guess it
+  ourself. Reported in :issue:`1372` by Andreas Schwab.
+
 1.4.0 (2019-01-04)
 ==================
 

src/gevent/libev/_corecffi_build.py

@@ -15,18 +15,6 @@ import struct
 __all__ = []
 
 
-def system_bits():
-    return struct.calcsize('P') * 8
-
-
-def st_nlink_type():
-    if sys.platform == "darwin" or sys.platform.startswith("freebsd"):
-        return "short"
-    if system_bits() == 32:
-        return "unsigned long"
-    return "long long"
-
-
 from cffi import FFI
 ffi = FFI()
 
@@ -38,11 +26,15 @@ def read_source(name):
 _cdef = read_source('_corecffi_cdef.c')
 _source = read_source('_corecffi_source.c')
 
-_cdef = _cdef.replace('#define GEVENT_ST_NLINK_T int', '')
+# These defines and uses help keep the C file readable and lintable by
+# C tools.
 _cdef = _cdef.replace('#define GEVENT_STRUCT_DONE int', '')
-_cdef = _cdef.replace('GEVENT_ST_NLINK_T', st_nlink_type())
 _cdef = _cdef.replace("GEVENT_STRUCT_DONE _;", '...;')
 
+_cdef = _cdef.replace('#define GEVENT_ST_NLINK_T int',
+                      'typedef int... nlink_t;')
+_cdef = _cdef.replace('GEVENT_ST_NLINK_T', 'nlink_t')
+
 
 if sys.platform.startswith('win'):
     # We must have the vfd_open, etc, functions on

src/gevent/libev/_corecffi_source.c

@@ -19,8 +19,8 @@ static void python_handle_error(void* handle, int revents);
 static void python_stop(void* handle);
 
 static void _gevent_generic_callback(struct ev_loop* loop,
-									 struct ev_watcher* watcher,
-									 int revents)
+				     struct ev_watcher* watcher,
+				     int revents)
 {
     void* handle = watcher->data;
     int cb_result = python_callback(handle, revents);
@@ -45,7 +45,7 @@ static void _gevent_generic_callback(struct ev_loop* loop,
         default:
             fprintf(stderr,
                     "WARNING: gevent: Unexpected return value %d from Python callback "
-                    "for watcher %p and handle %d\n",
+                    "for watcher %p and handle %p\n",
                     cb_result,
                     watcher, handle);
             // XXX: Possible leaking of resources here? Should we be

src/gevent/libuv/_corecffi_build.py

 # pylint: disable=no-member
 
-# This module is only used to create and compile the gevent._corecffi module;
+# This module is only used to create and compile the gevent.libuv._corecffi module;
 # nothing should be directly imported from it except `ffi`, which should only be
 # used for `ffi.compile()`; programs should import gevent._corecfffi.
 # However, because we are using "out-of-line" mode, it is necessary to examine
@@ -16,17 +16,6 @@ __all__ = []
 
 WIN = sys.platform.startswith('win32')
 
-def system_bits():
-    return struct.calcsize('P') * 8
-
-
-def st_nlink_type():
-    if sys.platform == "darwin" or sys.platform.startswith("freebsd"):
-        return "short"
-    if system_bits() == 32:
-        return "unsigned long"
-    return "long long"
-
 
 from cffi import FFI
 ffi = FFI()
@@ -39,12 +28,17 @@ def read_source(name):
 _cdef = read_source('_corecffi_cdef.c')
 _source = read_source('_corecffi_source.c')
 
-_cdef = _cdef.replace('#define GEVENT_ST_NLINK_T int', '')
+# These defines and uses help keep the C file readable and lintable by
+# C tools.
 _cdef = _cdef.replace('#define GEVENT_STRUCT_DONE int', '')
-_cdef = _cdef.replace('#define GEVENT_UV_OS_SOCK_T int', '')
-
-_cdef = _cdef.replace('GEVENT_ST_NLINK_T', st_nlink_type())
 _cdef = _cdef.replace("GEVENT_STRUCT_DONE _;", '...;')
+
+_cdef = _cdef.replace('#define GEVENT_ST_NLINK_T int',
+                      'typedef int... nlink_t;')
+_cdef = _cdef.replace('GEVENT_ST_NLINK_T', 'nlink_t')
+
+
+_cdef = _cdef.replace('#define GEVENT_UV_OS_SOCK_T int', '')
 # uv_os_sock_t is int on POSIX and SOCKET on Win32, but socket is
 # just another name for handle, which is just another name for 'void*'
 # which we will treat as an 'unsigned long' or 'unsigned long long'