the cb_data can be used by creating the structure with cb_data_new,
and then there are two possibilities:
- use it in a single callback function, and destroy it with a call to
g_free.
Example:
- calling function:
struct cb_data *cbd = cb_data_new(cb, data);
if (g_at_chat_send(chat, buf, NULL, at_cgatt_cb, cbd, g_free) > 0)
return;
g_free(cbd);
- called function (here at_cgatt_cb):
static void at_cgatt_cb(gboolean ok, GAtResult *result,
gpointer user_data)
{
struct cb_data *cbd = user_data;
ofono_gprs_cb_t cb = cbd->cb;
struct ofono_error error;
decode_at_error(&error,
g_at_result_final_response(result));
cb(&error, cbd->data);
}
note the absence of explicit g_free(cbd);
- pass it through a train of callback functions, adding a reference at
each pass cb_data_ref, and removing it with cb_data_unref.
the use of cb_data_ref would replace a new object creation, while the
use of cb_data_unref the use of g_free.
Example:
- calling function:
struct cb_data *cbd = cb_data_new(cb, data);
// no cb_ref at the creation
if (g_at_chat_send(chat, buf, NULL,
at_lte_set_default_attach_info_cb,
cbd, cb_data_unref) > 0)
goto end;
cb_data_unref(cbd);
- called function 1 (at_lte_set_default_attach_info_cb):
static void at_lte_set_default_attach_info_cb(gboolean ok,
GAtResult *result, gpointer user_data)
{
struct cb_data *cbd = user_data;
cbd = cb_data_ref(cbd);
if (g_at_chat_send(chat, buf, NULL,
at_cgatt_cb, cbd, cb_data_unref) > 0)
return;
cb_data_unref(cbd);
}
- called function 2 (at_cgatt_cb):
like above. no call to g_free or cb_data_unref. The terminal function
doesn't need to know about the reference scheme.
---
drivers/atmodem/atutil.h | 24 ++++++++++++++++++++++++
1 file changed, 24 insertions(+)
diff --git a/drivers/atmodem/atutil.h b/drivers/atmodem/atutil.h
index f1389a94..190ee17f 100644
--- a/drivers/atmodem/atutil.h
+++ b/drivers/atmodem/atutil.h
@@ -114,12 +114,36 @@ static inline struct cb_data *cb_data_new(void *cb, void
*data)
struct cb_data *ret;
ret = g_new0(struct cb_data, 1);
+ ret->ref_count = 1;
ret->cb = cb;
ret->data = data;
return ret;
}
+static inline struct cb_data *cb_data_ref(struct cb_data *cbd)
+{
+ if (cbd == NULL)
+ return NULL;
+
+ g_atomic_int_inc(&cbd->ref_count);
+
+ return cbd;
+}
+
+static inline void cb_data_unref(struct cb_data *cbd)
+{
+ gboolean is_zero;
+
+ if (cbd == NULL)
+ return;
+
+ is_zero = g_atomic_int_dec_and_test(&cbd->ref_count);
+
+ if (is_zero == TRUE)
+ g_free(cbd);
+}
+
static inline int at_util_convert_signal_strength(int strength)
{
int result;
--
2.17.1
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