Found out how to control the extension of distutils-built libraries.

Use a more suitable value by default when building embedded libraries.

3 files changed, 51 insertions, 6 deletions

diff --git a/cffi/api.py b/cffi/api.py
index 49b70a0..9f218a7 100644
--- a/cffi/api.py
+++ b/cffi/api.py
@@ -620,13 +620,25 @@ class FFI(object):
         recompile(self, module_name, source,
                   c_file=filename, call_c_compiler=False, **kwds)
 
-    def compile(self, tmpdir='.', verbose=0):
+    def compile(self, tmpdir='.', verbose=0, ext=None):
+        """Values recognized for the ext parameter:
+
+           - 'capi': use distutils' default to build CPython C API extensions
+           - 'system': use the system's default for dynamic libraries (.so/.dll)
+           - '.FOO': exactly .FOO
+
+           The default is 'capi' when building a non-embedded C API extension,
+           and 'system' when building an embedded library.
+        """
         from .recompiler import recompile
         #
         if not hasattr(self, '_assigned_source'):
             raise ValueError("set_source() must be called before compile()")
+        if ext not in (None, 'capi', 'system') and '.' not in ext:
+            raise ValueError("bad value for 'ext' argument: %r" % (ext,))
         module_name, source, source_extension, kwds = self._assigned_source
         return recompile(self, module_name, source, tmpdir=tmpdir,
+                         target_extention=ext,
                          source_extension=source_extension,
                          compiler_verbose=verbose, **kwds)
 
diff --git a/cffi/ffiplatform.py b/cffi/ffiplatform.py
index da2f5a5..039885b 100644
--- a/cffi/ffiplatform.py
+++ b/cffi/ffiplatform.py
@@ -21,12 +21,13 @@ def get_extension(srcfilename, modname, sources=(), **kwds):
         allsources.append(os.path.normpath(src))
     return Extension(name=modname, sources=allsources, **kwds)
 
-def compile(tmpdir, ext, compiler_verbose=0):
+def compile(tmpdir, ext, compiler_verbose=0, target_extention='capi'):
     """Compile a C extension module using distutils."""
 
     saved_environ = os.environ.copy()
     try:
-        outputfilename = _build(tmpdir, ext, compiler_verbose)
+        outputfilename = _build(tmpdir, ext, compiler_verbose,
+                                target_extention)
         outputfilename = os.path.abspath(outputfilename)
     finally:
         # workaround for a distutils bugs where some env vars can
@@ -36,7 +37,19 @@ def compile(tmpdir, ext, compiler_verbose=0):
                 os.environ[key] = value
     return outputfilename
 
-def _build(tmpdir, ext, compiler_verbose=0):
+def _save_val(name):
+    import distutils.sysconfig
+    config_vars = distutils.sysconfig.get_config_vars()
+    return config_vars.get(name, Ellipsis)
+
+def _restore_val(name, value):
+    import distutils.sysconfig
+    config_vars = distutils.sysconfig.get_config_vars()
+    config_vars[name] = value
+    if value is Ellipsis:
+        del config_vars[name]
+
+def _build(tmpdir, ext, compiler_verbose=0, target_extention='capi'):
     # XXX compact but horrible :-(
     from distutils.core import Distribution
     import distutils.errors, distutils.log
@@ -50,11 +63,25 @@ def _build(tmpdir, ext, compiler_verbose=0):
     #
     try:
         old_level = distutils.log.set_threshold(0) or 0
+        old_SO = _save_val('SO')
+        old_EXT_SUFFIX = _save_val('EXT_SUFFIX')
         try:
+            if target_extention == 'capi':
+                pass    # keep the values already in 'SO' and 'EXT_SUFFIX'
+            else:
+                if target_extention == 'system':
+                    if sys.platform == 'win32':
+                        target_extention = '.dll'
+                    else:
+                        target_extention = '.so'
+                _restore_val('SO', target_extention)
+                _restore_val('EXT_SUFFIX', target_extention)
             distutils.log.set_verbosity(compiler_verbose)
             dist.run_command('build_ext')
         finally:
             distutils.log.set_threshold(old_level)
+            _restore_val('SO', old_SO)
+            _restore_val('EXT_SUFFIX', old_EXT_SUFFIX)
     except (distutils.errors.CompileError,
             distutils.errors.LinkError) as e:
         raise VerificationError('%s: %s' % (e.__class__.__name__, e))
diff --git a/cffi/recompiler.py b/cffi/recompiler.py
index aaca566..8916a34 100644
--- a/cffi/recompiler.py
+++ b/cffi/recompiler.py
@@ -1359,7 +1359,7 @@ def _modname_to_file(outputdir, modname, extension):
 
 def recompile(ffi, module_name, preamble, tmpdir='.', call_c_compiler=True,
               c_file=None, source_extension='.c', extradir=None,
-              compiler_verbose=1, **kwds):
+              compiler_verbose=1, target_extention=None, **kwds):
     if not isinstance(module_name, str):
         module_name = module_name.encode('ascii')
     if ffi._windows_unicode:
@@ -1378,10 +1378,16 @@ def recompile(ffi, module_name, preamble, tmpdir='.', call_c_compiler=True,
         ext = ffiplatform.get_extension(ext_c_file, module_name, **kwds)
         updated = make_c_source(ffi, module_name, preamble, c_file)
         if call_c_compiler:
+            if target_extention is None:
+                if ffi._embedding is None:
+                    target_extention = 'capi'
+                else:
+                    target_extention = 'system'
             cwd = os.getcwd()
             try:
                 os.chdir(tmpdir)
-                outputfilename = ffiplatform.compile('.', ext, compiler_verbose)
+                outputfilename = ffiplatform.compile('.', ext, compiler_verbose,
+                                                     target_extention)
             finally:
                 os.chdir(cwd)
             return outputfilename