reduce complexity of finding andinitializing dll

pystacia/api/__init__.py

@@ -31,21 +31,69 @@ def dll_template(osname, abi):
     return None
 
 
-def find_library(name, abis, environ=None, osname=None, factory=None):
-    logger.debug('Trying to find ImageMagick...')
+def process_depends(depends_path, path, osname, factory):
+    depends = open(depends_path)
+
+    for line in depends:
+        depname, depabi = line.split()
+        template = formattable(dll_template(osname, depabi))
+        dll_path = join(path, template.format(name=depname,
+                                              abi=depabi))
+        try:
+            factory(dll_path)
+        except:
+            pass
 
-    paths = []
+    depends.close()
 
-    if not environ:
-        environ = os.environ
+
+def find_in_path(path, name, abis, osname, factory):
+    depends_path = join(path, 'depends.txt')
+    if exists(depends_path):
+        process_depends(depends_path, path, osname, factory)
+
+    for abi in abis:
+        template = dll_template(osname, abi)
+        if not template:
+            continue
+
+        template = formattable(template)
+
+        dll_path = join(path, template.format(name=name, abi=abi))
+
+        logger.debug('Trying: ' + dll_path)
+
+        if exists(dll_path):
+            logger.debug('Found: ' + dll_path)
+
+            if osname == 'windows':
+                old_path = getcwd()
+                chdir(path)
+
+            try:
+                factory(dll_path)
+            except:
+                from sys import exc_info
+                msg = formattable('Caught exception while loading '
+                                  '{0}: {1}. Rolling back')
+                logger.debug(msg.format(dll_path, exc_info()[1]))
+
+                if osname == 'windows':
+                    chdir(old_path)
+            else:
+                if osname == 'windows':
+                    chdir(old_path)
+
+                return dll_path
+
+
+def gather_paths(environ):
+    paths = []
 
     path = registry.get('library_path', environ.get('PYSTACIA_LIBRARY_PATH'))
     if path:
         paths.append(path)
 
-    if not osname:
-        osname = get_osname()
-
     if not registry.get('skip_package', environ.get('PYSTACIA_SKIP_PACKAGE')):
         import pystacia
         path = dirname(pystacia.__file__)
@@ -64,65 +112,33 @@ def find_library(name, abis, environ=None, osname=None, factory=None):
     if not registry.get('skip_cwd', environ.get('PYSTACIA_SKIP_CWD')):
         paths.append(getcwd())
 
+    return paths
+
+
+def find_library(name, abis, environ=None, osname=None, factory=None):
+    logger.debug('Trying to find ImageMagick...')
+
+    if not environ:
+        environ = os.environ
+
     if not factory:
         factory = CDLL
 
+    if not osname:
+        osname = get_osname()
+
+    paths = gather_paths(environ)
+
     logger.debug('Following paths will be searched: ' + ';'.join(paths))
 
     for path in paths:
         if not exists(path):
             logger.debug('Path does not exist: ' + path)
             continue
 
-        depends_path = join(path, 'depends.txt')
-        if exists(depends_path):
-            depends = open(depends_path)
-
-            for line in depends:
-                depname, depabi = line.split()
-                template = formattable(dll_template(osname, depabi))
-                dll_path = join(path, template.format(name=depname,
-                                                      abi=depabi))
-                try:
-                    factory(dll_path)
-                except:
-                    pass
-
-            depends.close()
-
-        for abi in abis:
-            template = dll_template(osname, abi)
-            if not template:
-                continue
-
-            template = formattable(template)
-
-            dll_path = join(path, template.format(name=name, abi=abi))
-
-            logger.debug('Trying: ' + dll_path)
-
-            if exists(dll_path):
-                logger.debug('Found: ' + dll_path)
-
-                if osname == 'windows':
-                    old_path = getcwd()
-                    chdir(path)
-
-                try:
-                    factory(dll_path)
-                except:
-                    from sys import exc_info
-                    msg = formattable('Caught exception while loading '
-                                      '{0}: {1}. Rolling back')
-                    logger.debug(msg.format(dll_path, exc_info()[1]))
-
-                    if osname == 'windows':
-                        chdir(old_path)
-                else:
-                    if osname == 'windows':
-                        chdir(old_path)
-
-                    return dll_path
+        dll_path = find_in_path(path, name, abis, osname, factory)
+        if dll_path:
+            return dll_path
 
     # still nothing? let ctypes figure it out
     if not registry.get('skip_system', environ.get('PYSTACIA_SKIP_SYSTEM')):
@@ -152,6 +168,33 @@ def rollback(self):
 __lock = Lock()
 
 
+def init_dll(dll):
+    def shutdown():
+        logger.debug('Cleaning up traced instances')
+        _cleanup()
+
+        c_call(None, 'terminus')
+
+        if jython:
+            from java.lang import System  # @UnresolvedImport
+            System.exit(0)
+
+    logger.debug('Critical section - init MagickWand')
+    with __lock:
+        if not dll.__inited:
+            c_call(None, 'genesis', __init=False)
+
+            logger.debug('Registering atexit handler')
+            atexit.register(shutdown)
+
+            dll.__inited = True
+
+    version = magick.get_version()
+    if version < min_version:
+        msg = formattable('Unsupported version of MagickWand {0}')
+        warn(msg.format(version))
+
+
 def get_dll(init=True, environ=None, isolated=False):
     """Find ImageMagick DLL and initialize it.
 
@@ -184,30 +227,7 @@ def get_dll(init=True, environ=None, isolated=False):
     dll = get_dll.__dll
 
     if init and not dll.__inited:
-        def shutdown():
-            logger.debug('Cleaning up traced instances')
-            _cleanup()
-
-            c_call(None, 'terminus')
-
-            if jython:
-                from java.lang import System  # @UnresolvedImport
-                System.exit(0)
-
-        logger.debug('Critical section - init MagickWand')
-        with __lock:
-            if not dll.__inited:
-                c_call(None, 'genesis', __init=False)
-
-                logger.debug('Registering atexit handler')
-                atexit.register(shutdown)
-
-                dll.__inited = True
-
-        version = magick.get_version()
-        if version < min_version:
-            msg = formattable('Unsupported version of MagickWand {0}')
-            warn(msg.format(version))
+        init_dll(dll)
 
     return dll