From 712c2028568df7760bc98d95577e35709078bfea Mon Sep 17 00:00:00 2001
From: Jeffery To <jeffery.to@gmail.com>
Date: Sun, 8 Nov 2020 21:51:09 +0800
Subject: [PATCH] Use CFFI in out-of-line API mode (#49)

Currently, ffi.py is called during setup to generate augeas.py; this
file would normally be used for out-of-line ABI mode. ffi.py is also
imported at run-time, instead of the generated augeas.py, and used in
in-line ABI mode.

This changes usage of CFFI to out-of-line API mode (CFFI's "main mode of
usage"): ffi.py is called during setup to generate _augeas.abi3.so (a C
extension module); this generated module is imported at run-time.

With this change, the headers/development files for augeas (i.e.
libaugeas-dev on Debian, augeas-devel on Fedora, etc.) and the C
compiler are required for build/setup. (These were not necessary
previously.)

Closes https://github.com/hercules-team/python-augeas/issues/48.
---
 augeas/__init__.py |  2 +-
 augeas/ffi.py      | 27 ++++++++++++++++++++++-----
 setup.py           |  1 +
 3 files changed, 24 insertions(+), 6 deletions(-)

--- a/augeas/__init__.py
+++ b/augeas/__init__.py
@@ -32,7 +32,7 @@ format and the transformation into a tre
 
 from sys import version_info as _pyver
 
-from augeas.ffi import ffi, lib
+from _augeas import ffi, lib
 
 __author__ = "Nathaniel McCallum <nathaniel@natemccallum.com>"
 __credits__ = """Jeff Schroeder <jeffschroeder@computer.org>
--- a/augeas/ffi.py
+++ b/augeas/ffi.py
@@ -1,9 +1,28 @@
+import os
+import subprocess
+
 from cffi import FFI
 
+def get_include_dirs():
+    XML2_CONFIG = os.environ.get('XML2_CONFIG', 'xml2-config')
+    PKG_CONFIG = os.environ.get('PKG_CONFIG', 'pkg-config')
+    try:
+        stdout = subprocess.check_output([XML2_CONFIG, '--cflags'])
+    except (OSError, subprocess.CalledProcessError):
+        try:
+            stdout = subprocess.check_output([PKG_CONFIG, '--cflags', 'libxml-2.0'])
+        except (OSError, subprocess.CalledProcessError):
+            stdout = b''
+    cflags = stdout.decode('utf-8').split()
+    return [cflag[2:] for cflag in cflags if cflag.startswith('-I')]
+
 ffi = FFI()
-ffi.set_source("augeas",
-               None,
-               libraries=['augeas'])
+ffi.set_source("_augeas",
+               """
+               #include <augeas.h>
+               """,
+               libraries=['augeas'],
+               include_dirs=get_include_dirs())
 
 ffi.cdef("""
 typedef struct augeas augeas;
@@ -44,7 +63,5 @@ const char *aug_error_details(augeas *au
 void free(void *);
 """)
 
-lib = ffi.dlopen("augeas")
-
 if __name__ == "__main__":
     ffi.compile(verbose=True)
--- a/setup.py
+++ b/setup.py
@@ -22,6 +22,7 @@ setup(name=name,
       setup_requires=["cffi>=1.0.0"],
       cffi_modules=["augeas/ffi.py:ffi"],
       install_requires=["cffi>=1.0.0"],
+      zip_safe=False,
       url="http://augeas.net/",
       classifiers=[
           "Programming Language :: Python :: 2.7",