Add support for metadata properties

Closes #40.

Author: mgeier

doc/fake__jack.py

@@ -24,6 +24,10 @@ class Fake(object):
     JackTransportStarting = 3
     JackTransportNetStarting = 4
 
+    PropertyCreated = 0
+    PropertyChanged = 1
+    PropertyDeleted = 2
+
     def dlopen(self, _):
         return self
 

examples/chatty_client.py

@@ -93,6 +93,23 @@ def xrun(delay):
     print('xrun; delay', delay, 'microseconds')
 
 
+try:
+    @client.set_property_change_callback
+    def property_change(subject, key, changed):
+        print('subject {}: '.format(subject), end='')
+        if not key:
+            assert changed == jack.PROPERTY_DELETED
+            print('all properties were removed')
+            return
+        print('property {!r} was {}'.format(key, {
+            jack.PROPERTY_CREATED: 'created',
+            jack.PROPERTY_CHANGED: 'changed',
+            jack.PROPERTY_DELETED: 'removed',
+        }[changed]))
+except jack.JackError as e:
+    print(e)
+
+
 print('activating JACK')
 with client:
     print('#' * 80)

examples/metadata.py

@@ -0,0 +1,30 @@
+#!/usr/bin/env python3
+"""Set/get/remove client/port metadata."""
+from pprint import pprint
+
+import jack
+
+client = jack.Client('Metadata-Client')
+port = client.inports.register('input')
+
+client.set_property(client.uuid, jack.METADATA_PRETTY_NAME, 'Best Client Ever')
+print('Client "pretty" name:',
+      jack.get_property(client.uuid, jack.METADATA_PRETTY_NAME))
+
+client.set_property(
+    port.uuid, jack.METADATA_PRETTY_NAME, b'a good port', 'text/plain')
+print('Port "pretty" name:',
+      jack.get_property(port.uuid, jack.METADATA_PRETTY_NAME))
+
+print('All client properties:')
+pprint(jack.get_properties(client.uuid))
+
+print('All port properties:')
+pprint(jack.get_properties(port.uuid))
+
+print('All properties:')
+pprint(jack.get_all_properties())
+
+client.remove_property(port.uuid, jack.METADATA_PRETTY_NAME)
+client.remove_properties(client.uuid)
+client.remove_all_properties()

jack_build.py

@@ -244,6 +244,45 @@
 /* session.h */
 
 char* jack_client_get_uuid(jack_client_t* client);
+
+/* uuid.h */
+
+extern int jack_uuid_parse(const char* buf, jack_uuid_t*);
+
+/* metadata.h */
+
+typedef struct {
+    const char* key;
+    const char* data;
+    const char* type;
+} jack_property_t;
+int jack_set_property(jack_client_t*, jack_uuid_t subject, const char* key, const char* value, const char* type);
+int jack_get_property(jack_uuid_t subject, const char* key, char** value, char** type);
+typedef struct {
+    jack_uuid_t subject;
+    uint32_t property_cnt;
+    jack_property_t* properties;
+    uint32_t property_size;
+} jack_description_t;
+void jack_free_description(jack_description_t* desc, int free_description_itself);
+int jack_get_properties(jack_uuid_t subject, jack_description_t* desc);
+int jack_get_all_properties(jack_description_t** descs);
+int jack_remove_property(jack_client_t* client, jack_uuid_t subject, const char* key);
+int jack_remove_properties(jack_client_t* client, jack_uuid_t subject);
+int jack_remove_all_properties(jack_client_t* client);
+typedef enum {
+    PropertyCreated,
+    PropertyChanged,
+    PropertyDeleted,
+} jack_property_change_t;
+typedef void (*JackPropertyChangeCallback)(jack_uuid_t subject, const char* key, jack_property_change_t change, void* arg);
+int jack_set_property_change_callback(jack_client_t* client, JackPropertyChangeCallback callback, void* arg);
+extern const char* JACK_METADATA_PRETTY_NAME;
+extern const char* JACK_METADATA_HARDWARE;
+extern const char* JACK_METADATA_CONNECTED;
+extern const char* JACK_METADATA_PORT_GROUP;
+extern const char* JACK_METADATA_ICON_SMALL;
+extern const char* JACK_METADATA_ICON_LARGE;
 """)
 
 # Packed structure