gras: work on module loading and python factory

naming convention, path convention, env var convention,

And, make a python factory -- but its a little halfassed.
You see, we didnt do the swig director thing yet,
so C++ cant yet create python blocks from the factory.

1 files changed, 48 insertions, 0 deletions

diff --git a/python/gras/GRAS_Loader.py b/python/gras/GRAS_Loader.py
new file mode 100644
index 0000000..b70bc60
--- /dev/null
+++ b/python/gras/GRAS_Loader.py
@@ -0,0 +1,48 @@
+# Copyright (C) by Josh Blum. See LICENSE.txt for licensing information.
+
+import os
+import sys
+
+#try to import module
+#http://effbot.org/zone/import-string.htm
+def __try_module_import(filename):
+    directory, module_name = os.path.split(filename)
+    module_name = os.path.splitext(module_name)[0]
+
+    path = list(sys.path)
+    sys.path.insert(0, directory)
+    try:
+        module = __import__(module_name)
+    except Exception as ex:
+        print 'Could not import', filename, ex
+    finally:
+        sys.path[:] = path # restore
+
+#recursive search for modules in path
+def __module_import(p):
+    if not os.path.exists(p): return
+    if os.path.isfile(p):
+        return __try_module_import(p)
+    if not os.path.isdir(p): return
+    if os.path.exists(os.path.join(p, '__init__.py')):
+        return __try_module_import(p)
+    for sub in os.listdir(p):
+        name, ext = os.path.splitext(sub)
+        #prefer .pyo over .pyc, prefer .pyc over .py
+        has_pyc = os.path.exists(os.path.join(p, name+'.pyc'))
+        has_pyo = os.path.exists(os.path.join(p, name+'.pyo'))
+        if ext == ".py" and (has_pyc or has_pyo): continue
+        if ext == ".pyc" and has_pyo: continue
+        __module_import(os.path.join(p, sub))
+
+#separate the paths and load each one
+def __load_modules_from_paths(paths, suffix):
+    if not paths: return
+    for path in paths.split(os.pathsep):
+        if not path: continue
+        if suffix: path = os.path.join(path, suffix)
+        __module_import(path)
+
+__load_modules_from_paths(os.getenv("GRAS_ROOT", "@GRAS_ROOT@"), os.path.join("lib@LIB_SUFFIX@", "gras", "python"))
+__load_modules_from_paths(os.getenv("GRAS_PATH", ""), os.path.join("lib@LIB_SUFFIX@", "gras", "python"))
+__load_modules_from_paths(os.getenv("GRAS_PYTHON_PATH", ""), "")