Start of ctypes-based python bindings for libcontextprovider.

2 files changed, 105 insertions, 0 deletions

diff --git a/python/CTypesHelpers.py b/python/CTypesHelpers.py
new file mode 100644
index 00000000..bada4e0d
--- /dev/null
+++ b/python/CTypesHelpers.py
@@ -0,0 +1,65 @@
+# From http://wwwx.cs.unc.edu/~gb/wp/blog/2007/02/11/ctypes-tricks/
+
+from ctypes import *
+
+def cfunc(name, dll, result, *args):
+    '''build and apply a ctypes prototype complete with parameter flags'''
+    atypes = []
+    aflags = []
+    for arg in args:
+        atypes.append(arg[1])
+        aflags.append((arg[2], arg[0]) + arg[3:])
+    return CFUNCTYPE(result, *atypes)((name, dll), tuple(aflags))
+
+class ListPOINTER(object):
+    '''Just like a POINTER but accept a list of ctype as an argument'''
+    def __init__(self, etype):
+        self.etype = etype
+
+    def from_param(self, param):
+        if isinstance(param, (list,tuple)):
+            return (self.etype * len(param))(*param)
+
+class ListPOINTER2(object):
+    '''Just like POINTER(POINTER(ctype)) but accept a list of lists of ctype'''
+    def __init__(self, etype):
+        self.etype = etype
+
+    def from_param(self, param):
+        if isinstance(param, (list,tuple)):
+            val = (POINTER(self.etype) * len(param))()
+            for i,v in enumerate(param):
+                if isinstance(v, (list,tuple)):
+                    val[i] = (self.etype * len(v))(*v)
+                else:
+                    raise TypeError, 'nested list or tuple required at %d' % i
+            return val
+        else:
+            raise TypeError, 'list or tuple required'
+
+
+class ByRefArg(object):
+    '''Just like a POINTER but accept an argument and pass it byref'''
+    def __init__(self, atype):
+        self.atype = atype
+
+    def from_param(self, param):
+        return byref(self.atype(param))
+
+# hack the ctypes.Structure class to include printing the fields
+class _Structure(Structure):
+    def __repr__(self):
+        '''Print the fields'''
+        res = []
+        for field in self._fields_:
+            res.append('%s=%s' % (field[0], repr(getattr(self, field[0]))))
+        return self.__class__.__name__ + '(' + ','.join(res) + ')'
+    @classmethod
+    def from_param(cls, obj):
+        '''Magically construct from a tuple'''
+        if isinstance(obj, cls):
+            return obj
+        if isinstance(obj, tuple):
+            return cls(*obj)
+        raise TypeError
+
diff --git a/python/ContextProvider.py b/python/ContextProvider.py
new file mode 100644
index 00000000..4048fc16
--- /dev/null
+++ b/python/ContextProvider.py
@@ -0,0 +1,40 @@
+from ctypes import *
+from CTypesHelpers import *
+
+
+class STRING_SET(c_void_p):
+    pass
+
+class CHANGE_SET(c_void_p):
+    pass
+
+class ContextProvider:
+    def __init__(self):
+        self.define_types()
+        self.define_functions()
+
+    def define_types(self):
+        self.dll = CDLL("libcontextprovider.so")
+        self.STRING_ARRAY = POINTER(c_char_p)
+        self.GET_CALLBACK = CFUNCTYPE(STRING_SET, CHANGE_SET, c_void_p)
+        self.SUBSCRIBE_CALLBACK = CFUNCTYPE(STRING_SET, c_void_p)
+
+    def define_functions(self):
+        self.init = cfunc('context_provider_init', self.dll, None,
+                            ('provided_keys', ListPOINTER (c_char_p), 1),
+                            ('useSessionBus', c_int, 1),
+                            ('get_cb', self.GET_CALLBACK, 1),
+                            ('get_cb_target', c_void_p, 1),
+                            ('first_cb', self.SUBSCRIBE_CALLBACK, 1),
+                            ('first_cb_target', c_void_p, 1),
+                            ('last_cb', self.SUBSCRIBE_CALLBACK, 1),
+                            ('last_cb_target', c_void_p, 1))
+        self.no_of_subscribers = cfunc('context_provider_no_of_subscribers', self.dll, c_int,
+                                    ('key', c_char_p, 1))
+
+        self.change_set_create = ('context_provider_change_set_create', self.dll, CHANGE_SET,
+                                    None);
+
+
+if __name__ == "__main__":
+    cp = ContextProvider()