Python wrapper: support for inbound group sessions

1 files changed, 86 insertions, 0 deletions

diff --git a/python/olm/inbound_group_session.py b/python/olm/inbound_group_session.py
new file mode 100644
index 0000000..6c01095
--- /dev/null
+++ b/python/olm/inbound_group_session.py
@@ -0,0 +1,86 @@
+import json
+
+from ._base import *
+
+lib.olm_inbound_group_session_size.argtypes = []
+lib.olm_inbound_group_session_size.restype = c_size_t
+
+lib.olm_inbound_group_session.argtypes = [c_void_p]
+lib.olm_inbound_group_session.restype = c_void_p
+
+lib.olm_inbound_group_session_last_error.argtypes = [c_void_p]
+lib.olm_inbound_group_session_last_error.restype = c_char_p
+
+def inbound_group_session_errcheck(res, func, args):
+    if res == ERR:
+        raise OlmError("%s: %s" % (
+            func.__name__, lib.olm_inbound_group_session_last_error(args[0])
+        ))
+    return res
+
+
+def inbound_group_session_function(func, *types):
+    func.argtypes = (c_void_p,) + types
+    func.restypes = c_size_t
+    func.errcheck = inbound_group_session_errcheck
+
+
+inbound_group_session_function(
+    lib.olm_pickle_inbound_group_session, c_void_p, c_size_t, c_void_p, c_size_t
+)
+inbound_group_session_function(
+    lib.olm_unpickle_inbound_group_session, c_void_p, c_size_t, c_void_p, c_size_t
+)
+
+inbound_group_session_function(
+    lib.olm_init_inbound_group_session, c_uint32, c_void_p, c_size_t
+)
+
+inbound_group_session_function(
+    lib.olm_group_decrypt_max_plaintext_length, c_void_p, c_size_t
+)
+inbound_group_session_function(
+    lib.olm_group_decrypt,
+    c_void_p, c_size_t, # message
+    c_void_p, c_size_t, # plaintext
+)
+
+class InboundGroupSession(object):
+    def __init__(self):
+        self.buf = create_string_buffer(lib.olm_inbound_group_session_size())
+        self.ptr = lib.olm_inbound_group_session(self.buf)
+
+    def pickle(self, key):
+        key_buffer = create_string_buffer(key)
+        pickle_length = lib.olm_pickle_inbound_group_session_length(self.ptr)
+        pickle_buffer = create_string_buffer(pickle_length)
+        lib.olm_pickle_inbound_group_session(
+            self.ptr, key_buffer, len(key), pickle_buffer, pickle_length
+        )
+        return pickle_buffer.raw
+
+    def unpickle(self, key, pickle):
+        key_buffer = create_string_buffer(key)
+        pickle_buffer = create_string_buffer(pickle)
+        lib.olm_unpickle_inbound_group_session(
+            self.ptr, key_buffer, len(key), pickle_buffer, len(pickle)
+        )
+
+    def init(self, message_index, session_key):
+        key_buffer = create_string_buffer(session_key)
+        lib.olm_init_inbound_group_session(
+            self.ptr, message_index, key_buffer, len(session_key)
+        )
+
+    def decrypt(self, message):
+        message_buffer = create_string_buffer(message)
+        max_plaintext_length = lib.olm_group_decrypt_max_plaintext_length(
+            self.ptr, message_buffer, len(message)
+        )
+        plaintext_buffer = create_string_buffer(max_plaintext_length)
+        message_buffer = create_string_buffer(message)
+        plaintext_length = lib.olm_group_decrypt(
+            self.ptr, message_buffer, len(message),
+            plaintext_buffer, max_plaintext_length
+        )
+        return plaintext_buffer.raw[:plaintext_length]