shl: register: add destroy callback

The new destroy callback is called whenever an entries last reference is
dropped. This will allow modules to keep reference of its code users.

Signed-off-by: David Herrmann <dh.herrmann@googlemail.com>

diff --git a/src/shl_register.h b/src/shl_register.h
index df1d3d5..d00edff 100644 (file)
--- a/src/shl_register.h
+++ b/src/shl_register.h
@@ -45,6 +45,8 @@
 #include <string.h>
 #include "shl_dlist.h"
 
+typedef void (*shl_register_destroy_cb) (void *data);
+
 struct shl_register_record {
        struct shl_dlist list;
 
@@ -52,6 +54,7 @@ struct shl_register_record {
        unsigned long ref;
        char *name;
        void *data;
+       shl_register_destroy_cb destroy;
 };
 
 struct shl_register {
@@ -95,6 +98,8 @@ static inline void shl_register_record_unref(struct shl_register_record *record)
        if (ref)
                return;
 
+       if (record->destroy)
+               record->destroy(record->data);
        pthread_mutex_destroy(&record->mutex);
        free(record->name);
        free(record);
@@ -147,8 +152,9 @@ static inline void shl_register_free(struct shl_register *reg)
        free(reg);
 }
 
-static inline int shl_register_add(struct shl_register *reg, const char *name,
-                                  void *data)
+static inline int shl_register_add_cb(struct shl_register *reg,
+                                     const char *name, void *data,
+                                     shl_register_destroy_cb destroy)
 {
        struct shl_dlist *iter;
        struct shl_register_record *record;
@@ -178,6 +184,7 @@ static inline int shl_register_add(struct shl_register *reg, const char *name,
        memset(record, 0, sizeof(*record));
        record->ref = 1;
        record->data = data;
+       record->destroy = destroy;
 
        ret = pthread_mutex_init(&record->mutex, NULL);
        if (ret) {
@@ -204,6 +211,12 @@ out_unlock:
        return ret;
 }
 
+static inline int shl_register_add(struct shl_register *reg, const char *name,
+                                  void *data)
+{
+       return shl_register_add_cb(reg, name, data, NULL);
+}
+
 static inline void shl_register_remove(struct shl_register *reg,
                                       const char *name)
 {