Add destructor for demarshalled messages

This is required because we don't want to free messages that just
refer to the unparsed message (like SpiceMsgData).

Also, in the future we might need it for more complex demarshalling.

1 files changed, 18 insertions, 7 deletions

diff --git a/python_modules/demarshal.py b/python_modules/demarshal.py
index 8b90458c..b1c41354 100644
--- a/python_modules/demarshal.py
+++ b/python_modules/demarshal.py
@@ -41,9 +41,10 @@ def write_parser_helpers(writer):
 
     writer.newline()
     writer.statement("typedef struct PointerInfo PointerInfo")
+    writer.statement("typedef void (*message_destructor_t)(uint8_t *message)");
     writer.statement("typedef uint8_t * (*parse_func_t)(uint8_t *message_start, uint8_t *message_end, uint8_t *struct_data, PointerInfo *ptr_info, int minor)")
-    writer.statement("typedef uint8_t * (*parse_msg_func_t)(uint8_t *message_start, uint8_t *message_end, int minor, size_t *size_out)")
-    writer.statement("typedef uint8_t * (*spice_parse_channel_func_t)(uint8_t *message_start, uint8_t *message_end, uint16_t message_type, int minor, size_t *size_out)")
+    writer.statement("typedef uint8_t * (*parse_msg_func_t)(uint8_t *message_start, uint8_t *message_end, int minor, size_t *size_out, message_destructor_t *free_message)")
+    writer.statement("typedef uint8_t * (*spice_parse_channel_func_t)(uint8_t *message_start, uint8_t *message_end, uint16_t message_type, int minor, size_t *size_out, message_destructor_t *free_message)")
 
     writer.newline()
     writer.begin_block("struct PointerInfo")
@@ -820,6 +821,13 @@ def write_ptr_info_check(writer):
                 writer.error_check("end == NULL")
     writer.newline()
 
+def write_nofree(writer):
+    if writer.is_generated("helper", "nofree"):
+        return
+    writer = writer.function_helper()
+    scope = writer.function("nofree", "static void", "uint8_t *data")
+    writer.end_block()
+
 def write_msg_parser(writer, message):
     msg_name = message.c_name()
     function_name = "parse_%s" % msg_name
@@ -833,7 +841,7 @@ def write_msg_parser(writer, message):
     writer.newline()
     parent_scope = writer.function(function_name,
                                    "uint8_t *",
-                                   "uint8_t *message_start, uint8_t *message_end, int minor, size_t *size", True)
+                                   "uint8_t *message_start, uint8_t *message_end, int minor, size_t *size, message_destructor_t *free_message", True)
     parent_scope.variable_def("SPICE_GNUC_UNUSED uint8_t *", "pos");
     parent_scope.variable_def("uint8_t *", "start = message_start");
     parent_scope.variable_def("uint8_t *", "data = NULL");
@@ -860,8 +868,10 @@ def write_msg_parser(writer, message):
     writer.newline().comment("Validated extents and calculated size").newline()
 
     if message.has_attr("nocopy"):
+        write_nofree(writer)
         writer.assign("data", "message_start")
         writer.assign("*size", "message_end - message_start")
+        writer.assign("*free_message", "nofree")
     else:
         writer.assign("data", "(uint8_t *)malloc(mem_size)")
         writer.error_check("data == NULL")
@@ -882,6 +892,7 @@ def write_msg_parser(writer, message):
 
         writer.newline()
         writer.assign("*size", "end - data")
+        writer.assign("*free_message", "(message_destructor_t) free")
 
     writer.statement("return data")
     writer.newline()
@@ -922,7 +933,7 @@ def write_channel_parser(writer, channel, server):
     writer.newline()
     scope = writer.function(function_name,
                             "uint8_t *",
-                            "uint8_t *message_start, uint8_t *message_end, uint16_t message_type, int minor, size_t *size_out")
+                            "uint8_t *message_start, uint8_t *message_end, uint16_t message_type, int minor, size_t *size_out, message_destructor_t *free_message")
 
     helpers = writer.function_helper()
 
@@ -944,7 +955,7 @@ def write_channel_parser(writer, channel, server):
     for r in ranges:
         d = d + 1
         with writer.if_block("message_type >= %d && message_type < %d" % (r[0], r[1]), d > 1, False):
-            writer.statement("return funcs%d[message_type-%d](message_start, message_end, minor, size_out)" % (d, r[0]))
+            writer.statement("return funcs%d[message_type-%d](message_start, message_end, minor, size_out, free_message)" % (d, r[0]))
     writer.newline()
 
     writer.statement("return NULL")
@@ -1006,7 +1017,7 @@ def write_full_protocol_parser(writer, is_server):
         function_name = "spice_parse_reply"
     scope = writer.function(function_name,
                             "uint8_t *",
-                            "uint8_t *message_start, uint8_t *message_end, uint32_t channel, uint16_t message_type, int minor, size_t *size_out")
+                            "uint8_t *message_start, uint8_t *message_end, uint32_t channel, uint16_t message_type, int minor, size_t *size_out, message_destructor_t *free_message")
     scope.variable_def("spice_parse_channel_func_t", "func" )
 
     if is_server:
@@ -1015,7 +1026,7 @@ def write_full_protocol_parser(writer, is_server):
         writer.assign("func", "spice_get_client_channel_parser(channel, NULL)")
 
     with writer.if_block("func != NULL"):
-        writer.statement("return func(message_start, message_end, message_type, minor, size_out)")
+        writer.statement("return func(message_start, message_end, message_type, minor, size_out, free_message)")
 
     writer.statement("return NULL")
     writer.end_block()