Commit 1752d8dd authored by Sven Gestegård Robertz's avatar Sven Gestegård Robertz
Browse files

pragma todo added

parent fbeec9d9
Discussion 141023
*** new labcomm packet types:
TYPE_DEF = 0x03 // for (possibly) hierarchical type definitions
TYPE_BINDING = 0x04 // binding a sample def to a type def
*** rewrite malloc of received samples to utilize the packet length field
to allocate a single object before parsing the sample byte stream
*** labcomm language: add type for type_ref to facilitate references to
labcomm sample_defs (and type_defs) in (primarily) pragmas
E.g., sample ... foo;
sample ... bar;
sample struct {
type[2] some_refs;
} some_pragma;
my_lc_some_pragma sp;
sp.some_refs = {&labcomm_signature_my_lc_foo,
labcomm_encode_my_lc_some_pragma(enc, &sp);
This is to avoid exposing local_to_remote and remote_to_local
*** refactor {encoder,decoder}registry to separate the actual encoder
from the registry
- currently, the assignment of local indices is done in the "constructor"
which means that the registries will be very thin
*** labcomm_pragma_builder(struct labcomm_encoder *enc);
- looks like an encoder to enable reuse of the generated encode functions
- allocates memory in the enclosing encoder, enc.
- deallocates memory when packet is sent
*** Pragma handler
- is a decoder, to which the user registers handlers for pragma samples
- has/gets a byte_array_reader in the context
- the "surrounding" decoder will deallocate the pragma packet when the
pragma handler returns
______________preliminary sketch of pragma____________________
A pragma "packet" is a sequence of fields, where each field is
a labcomm sample (in order to keep labcomm in-band self-describing).
A pragma packet has a type, which is a globally unique string
A pragma packet has a type, which is a globally unique string
(e.g., java package-like name, URI, or UUID)
One predefined pragma sample type is labcomm_type_ref, which is used to refer
......@@ -20,8 +75,8 @@ struct labcom_pragma_packet * = labcomm_pragma_new(struct labcomm_encoder e*,
void labcomm_pragma_add_ref(struct labcomm_signature sig);
// the semantics if more than one type reference field is undefined
// (as far as labcomm is concerned).
// One possible (pragma-type defined) semantic is that the latest type
// (as far as labcomm is concerned).
// One possible (pragma-type defined) semantic is that the latest type
// reference applies to the fields following it.
A pragma packet is (under the hood) a struct labcomm_encoder, so that we
......@@ -37,13 +92,13 @@ labcomm_pragma_send(pp, enc);
#define labcomm_pragma_add_field(some_pragma_sample_type, value) \
labcomm_encode_#some_pragma_sample_type, value)
labcomm_encode_#some_pragma_sample_type, value)
int labcomm_encode_test_twoLines( struct labcomm_encoder *e,
int labcomm_encode_test_twoLines( struct labcomm_encoder *e,
test_twoLines *v)
return labcomm_internal_encode(e,
return labcomm_internal_encode(e,
(labcomm_enc oder_function) encode_test_twoLines,
......@@ -56,16 +111,30 @@ alt 1. standard handlers, parameter pragma_type to handle function
-- this means adding a parameter to all handlers
(where null means not pragma)
void handle_some_pragma(some_pragma *v, void *context, char * pragma_type);
alt 2. standard handlers, but separate register_pragma_handler function
use the handler context to store and communicate pragma-specific data.
-- this means that the decoder interface needs to be extended,
and that the handler context for pragmas need to be specified
(by labcomm)
(by labcomm)
alt 3 have a single handler for pragma packets as the interface upwards
from the labcomm lib. That handler is then responsible for managing
and multiplexing pragma types based on the type field in the pragma
void handle_some_pragma(some_pragma *v, void *context, char * pragma_type);
The labcomm libraries can provide a default implementation of a
pragma_handler, to facilitate the common cases and reduce the
amount of boilerplate code.
struct pragma_packet {
char *pragma_type;
char *packed_data;
void handle_pragma(struct pragma_packet *p, void *context);
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