Get libev-cffi building and using a non-embedded libev.so

.travis.yml

@@ -143,6 +143,10 @@ jobs:
         - rm -rf $BUILD_LIBS/share/man/
         - ls -l $BUILD_LIBS $BUILD_LIBS/lib
         - pip install --no-build-isolation .[test]
+        - objdump -p src/gevent/libev/*so
+      script:
+        # Verify that we got non-embedded builds
+        - python -c 'import gevent.libev.corecffi as CF; assert not CF.LIBEV_EMBED'
 
     # Ok, now we switch to the test stage. These are all in addition
     # to the jobs created by the matrix (and should override the `script` command).

_setuplibev.py

 # -*- coding: utf-8 -*-
 """
 setup helpers for libev.
+
+Importing this module should have no side-effects; in particular,
+it shouldn't attempt to cythonize anything.
 """
 
 from __future__ import print_function, absolute_import, division
@@ -60,7 +63,11 @@ def configure_libev(bext, ext):
     finally:
         os.chdir(cwd)
 
-CORE = Extension(name='gevent.libev.corecext',
+def build_extension():
+    # Return the un-cythonized extension.
+    # This can be used to access things like `libraries` and `include_dirs`
+    # and `define_macros` so we DRY.
+    CORE = Extension(name='gevent.libev.corecext',
                      sources=[
                          'src/gevent/libev/corecext.pyx',
                          'src/gevent/libev/callbacks.c',
@@ -72,11 +79,11 @@ CORE = Extension(name='gevent.libev.corecext',
                                        'src/gevent/libev/stathelper.c',
                                        'src/gevent/libev/libev*.h',
                                        'deps/libev/*.[ch]'))
-if WIN:
+    if WIN:
         CORE.define_macros.append(('EV_STANDALONE', '1'))
-# QQQ libev can also use -lm, however it seems to be added implicitly
+    # QQQ libev can also use -lm, however it seems to be added implicitly
 
-if LIBEV_EMBED:
+    if LIBEV_EMBED:
         CORE.define_macros += [('LIBEV_EMBED', '1'),
                                ('EV_COMMON', ''),  # we don't use void* data
                                # libev watchers that we don't use currently:
@@ -88,7 +95,8 @@ if LIBEV_EMBED:
             os.environ["CPPFLAGS"] = ("%s %s" % (os.environ.get("CPPFLAGS", ""), "-U__llvm__")).lstrip()
         if os.environ.get('GEVENTSETUP_EV_VERIFY') is not None:
             CORE.define_macros.append(('EV_VERIFY', os.environ['GEVENTSETUP_EV_VERIFY']))
-else:
+    else:
+        CORE.define_macros += [('LIBEV_EMBED', '0')]
         CORE.libraries.append('ev')
 
-CORE = cythonize1(CORE)
+    return CORE

setup.py

@@ -46,10 +46,11 @@ __version__ = read_version()
 
 from _setuplibev import libev_configure_command
 from _setuplibev import LIBEV_EMBED
-from _setuplibev import CORE
-
+from _setuplibev import build_extension as build_libev_extension
 from _setupares import ARES
 
+CORE = cythonize1(build_libev_extension())
+
 # Get access to the greenlet header file.
 # The sysconfig dir is not enough if we're in a virtualenv
 # See https://github.com/pypa/pip/issues/4610

src/gevent/libev/_corecffi_build.py

@@ -10,21 +10,28 @@ from __future__ import absolute_import, print_function
 import sys
 import os
 import os.path # pylint:disable=no-name-in-module
+from cffi import FFI
+
+# We must be run from the directory containing setup.py.
+import _setuplibev
+
+thisdir = os.path.dirname(os.path.abspath(__file__))
+setup_dir = os.path.abspath(os.path.join(thisdir, '..', '..', '..'))
 
 
 __all__ = []
 
 
-from cffi import FFI
 ffi = FFI()
 
-thisdir = os.path.dirname(os.path.abspath(__file__))
+
 def read_source(name):
     with open(os.path.join(thisdir, name), 'r') as f:
         return f.read()
 
+# cdef goes to the cffi library and determines what can be used in
+# Python.
 _cdef = read_source('_corecffi_cdef.c')
-_source = read_source('_corecffi_source.c')
 
 # These defines and uses help keep the C file readable and lintable by
 # C tools.
@@ -35,6 +42,14 @@ _cdef = _cdef.replace('#define GEVENT_ST_NLINK_T int',
                       'typedef int... nlink_t;')
 _cdef = _cdef.replace('GEVENT_ST_NLINK_T', 'nlink_t')
 
+if _setuplibev.LIBEV_EMBED:
+    _cdef += """
+struct ev_loop {
+    int backend_fd;
+    int activecnt;
+    ...;
+};
+"""
 
 if sys.platform.startswith('win'):
     # We must have the vfd_open, etc, functions on
@@ -49,14 +64,20 @@ vfd_socket_t vfd_get(int);
 void vfd_free(int);
 """
 
+# source goes to the C compiler
+_source = read_source('_corecffi_source.c')
+
 
+distutils_ext = _setuplibev.build_extension()
 
-include_dirs = [
-    thisdir, # libev_vfd.h
-    os.path.abspath(os.path.join(thisdir, '..', '..', '..', 'deps', 'libev')),
-]
 ffi.cdef(_cdef)
-ffi.set_source('gevent.libev._corecffi', _source, include_dirs=include_dirs)
+ffi.set_source(
+    'gevent.libev._corecffi',
+    _source,
+    include_dirs=distutils_ext.include_dirs,
+    define_macros=distutils_ext.define_macros,
+    libraries=distutils_ext.libraries,
+)
 
 if __name__ == '__main__':
     # XXX: Note, on Windows, we would need to specify the external libraries
@@ -64,4 +85,17 @@ if __name__ == '__main__':
     # Python.h calls) the proper Python library---at least for PyPy. I never got
     # that to work though, and calling python functions is strongly discouraged
     # from CFFI code.
-    ffi.compile()
+
+    # On macOS to make the non-embedded case work correctly, against
+    # our local copy of libev:
+    #
+    # 1) configure and make libev
+    # 2) CPPFLAGS=-Ideps/libev/ LDFLAGS=-Ldeps/libev/.libs GEVENTSETUP_EMBED_LIBEV=0 \
+    #     python setup.py build_ext -i
+    # 3) export DYLD_LIBRARY_PATH=`pwd`/deps/libev/.libs
+    #
+    # XXX: The DYLD_LIBRARY_PATH is because the linker hard-codes
+    # /usr/local/lib/libev.4.dylib in the corecffi.so dylib, because
+    # that's the "install name" of the libev dylib that was built.
+    # Adding a -rpath to the LDFLAGS doesn't change things.
+    ffi.compile(verbose=True)

src/gevent/libev/_corecffi_cdef.c

+/* access whether we built embedded or not */
+
+#define LIBEV_EMBED ...
+
 /* libev interface */
 
 #define EV_MINPRI ...
@@ -55,11 +59,9 @@
 #define GEVENT_STRUCT_DONE int
 #define GEVENT_ST_NLINK_T int
 
-struct ev_loop {
-    int backend_fd;
-    int activecnt;
-    GEVENT_STRUCT_DONE _;
-};
+/* Note that we don't declare the ev_loop struct and fields here. */
+/* If we don't embed libev, we can't access those fields, libev */
+/* keeps it opaque.  */
 
 // Watcher types
 // base for all watchers

src/gevent/libev/_corecffi_source.c

-// passed to the real C compiler
+/* passed to the real C compiler */
+#ifndef LIBEV_EMBED
+/* We're normally used to embed libev, assume that */
+/* When this is defined, libev.h includes ev.c */
 #define LIBEV_EMBED 1
+#endif
 
 #ifdef _WIN32
 #define EV_STANDALONE 1

src/gevent/libev/corecffi.py

@@ -389,7 +389,9 @@ class loop(AbstractLoop):
             libev.gevent_reset_sigchld_handler()
 
     def fileno(self):
-        if self._ptr:
+        if self._ptr and LIBEV_EMBED:
+            # If we don't embed, we can't access these fields,
+            # the type is opaque
             fd = self._ptr.backend_fd
             if fd >= 0:
                 return fd
@@ -398,7 +400,9 @@ class loop(AbstractLoop):
     def activecnt(self):
         if not self._ptr:
             raise ValueError('operation on destroyed loop')
+        if LIBEV_EMBED:
             return self._ptr.activecnt
+        return -1
 
 
 @ffi.def_extern()
@@ -424,4 +428,4 @@ def set_syserr_cb(callback):
 
 __SYSERR_CALLBACK = None
 
-LIBEV_EMBED = True
+LIBEV_EMBED = libev.LIBEV_EMBED

src/gevent/libev/libev.h

-#if defined(LIBEV_EMBED)
-#include "ev.c"
-#undef LIBEV_EMBED
-#define LIBEV_EMBED 1
-#define gevent_ev_loop_origflags(loop) ((loop)->origflags)
-#define gevent_ev_loop_sig_pending(loop) ((loop))->sig_pending
-#define gevent_ev_loop_backend_fd(loop) ((loop))->backend_fd
-#define gevent_ev_loop_activecnt(loop) ((loop))->activecnt
-#if EV_USE_SIGNALFD
-#define gevent_ev_loop_sigfd(loop) ((loop))->sigfd
-#else
-#define gevent_ev_loop_sigfd(loop) -1
-#endif /* !EV_USE_SIGNALFD */
+#if defined(LIBEV_EMBED) && LIBEV_EMBED
+  #include "ev.c"
+  #undef LIBEV_EMBED
+  #define LIBEV_EMBED 1
+  #define gevent_ev_loop_origflags(loop) ((loop)->origflags)
+  #define gevent_ev_loop_sig_pending(loop) ((loop))->sig_pending
+  #define gevent_ev_loop_backend_fd(loop) ((loop))->backend_fd
+  #define gevent_ev_loop_activecnt(loop) ((loop))->activecnt
+  #if EV_USE_SIGNALFD
+    #define gevent_ev_loop_sigfd(loop) ((loop))->sigfd
+  #else
+    #define gevent_ev_loop_sigfd(loop) -1
+  #endif /* !EV_USE_SIGNALFD */
 #else /* !LIBEV_EMBED */
 #include "ev.h"