added setup_extension() method to ext_module to return

distutils.core.Extension object for a weave generated extension.  This
is helpful in using weave extensions within setup.py files.

added logic inside ext_module.generate_module to check whether the
new extension module code is different from the code that may already 
exist in a previously generated extension module file.  If the code is
the same, the file is not overwritten.  This prevents setup.py from thinking
the module is always out of date and must be recompiled.

1 files changed, 38 insertions, 18 deletions

diff --git a/weave/ext_tools.py b/weave/ext_tools.py
index 6d21e11ef..241e98d6e 100644
--- a/weave/ext_tools.py
+++ b/weave/ext_tools.py
@@ -283,19 +283,8 @@ class ext_module:
         for i in self.functions:
             i.set_compiler(compiler)
         self.compiler = compiler    
-        
-    def compile(self,location='.',compiler=None, verbose = 0, **kw):
-        
-        if compiler is not None:
-            self.compiler = compiler
-        
-        # !! removed -- we don't have any compiler dependent code
-        # currently in spec or info classes    
-        # hmm.  Is there a cleaner way to do this?  Seems like
-        # choosing the compiler spagettis around a little.        
-        #compiler = build_tools.choose_compiler(self.compiler)    
-        #self.set_compiler(compiler)
-        
+
+    def build_kw_and_file(self,location,kw):    
         arg_specs = self.arg_specs()
         info = self.build_information()
         _source_files = info.sources()
@@ -316,8 +305,28 @@ class ext_module:
                                    info.extra_compile_args()
         kw['extra_link_args'] = kw.get('extra_link_args',[]) + \
                                    info.extra_link_args()
-        
+        kw['sources'] = kw.get('sources',[]) + source_files        
         file = self.generate_file(location=location)
+        return kw,file
+    
+    def setup_extension(self,location='.',**kw):
+        kw,file = self.build_kw_and_file(location,kw)
+        return build_tools.create_extension(file, **kw)
+            
+    def compile(self,location='.',compiler=None, verbose = 0, **kw):
+        
+        if compiler is not None:
+            self.compiler = compiler
+        
+        # !! removed -- we don't have any compiler dependent code
+        # currently in spec or info classes    
+        # hmm.  Is there a cleaner way to do this?  Seems like
+        # choosing the compiler spagettis around a little.        
+        #compiler = build_tools.choose_compiler(self.compiler)    
+        #self.set_compiler(compiler)
+        
+        kw,file = self.build_kw_and_file(location,kw)
+        
         # This is needed so that files build correctly even when different
         # versions of Python are running around.
         # Imported at beginning of file now to help with test paths.
@@ -327,7 +336,6 @@ class ext_module:
         temp = catalog.intermediate_dir()
                 
         success = build_tools.build_extension(file, temp_dir = temp,
-                                              sources = source_files,                                              
                                               compiler_name = compiler,
                                               verbose = verbose, **kw)
         if not success:
@@ -338,9 +346,21 @@ def generate_file_name(module_name,module_location):
     return os.path.abspath(module_file)
 
 def generate_module(module_string, module_file):
-    f =open(module_file,'w')
-    f.write(module_string)
-    f.close()
+    """ generate the source code file.  Only overwrite
+        the existing file if the actual source has changed.
+    """
+    file_changed = 1
+    if os.path.exists(module_file):
+        f =open(module_file,'r')
+        old_string = f.read()
+        f.close()
+        if old_string == module_string:
+            file_changed = 0
+    if file_changed:
+        print 'file changed'
+        f =open(module_file,'w')
+        f.write(module_string)
+        f.close()
     return module_file
 
 def assign_variable_types(variables,local_dict = {}, global_dict = {},