This patch adds the btd_gatt_read_attribute() helper. It reads the
attribute value based on its read callback function. The callback can
the an abstraction for reading an external object proxy or a remote
attribute, acting as a helper function for server and client
implementations.
---
src/gatt.c | 22 ++++++++++++++++++++++
src/gatt.h | 9 +++++++++
2 files changed, 31 insertions(+)
diff --git a/src/gatt.c b/src/gatt.c
index 059e085..0137123 100644
--- a/src/gatt.c
+++ b/src/gatt.c
@@ -25,6 +25,7 @@
#include <config.h>
#endif
+#include <errno.h>
#include <glib.h>
#include "log.h"
@@ -194,6 +195,27 @@ fail:
return NULL;
}
+void btd_gatt_read_attribute(struct btd_attribute *attr,
+ btd_attr_read_result_t result,
+ void *user_data)
+{
+ /*
+ * When read_cb is available, it means that the attribute value
+ * is dynamic, and its value must be read from the external
+ * implementation. If "value_len" is set, the attribute value is
+ * constant. Additional checking are performed by the attribute server
+ * when the ATT Read request arrives based on the characteristic
+ * properties. At this point, properties bitmask doesn't need to be
+ * checked.
+ */
+ if (attr->read_cb)
+ attr->read_cb(attr, result, user_data);
+ else if (attr->value_len > 0)
+ result(0, attr->value, attr->value_len, user_data);
+ else
+ result(EPERM, NULL, 0, user_data);
+}
+
void gatt_init(void)
{
DBG("Starting GATT server");
diff --git a/src/gatt.h b/src/gatt.h
index 0021076..4363769 100644
--- a/src/gatt.h
+++ b/src/gatt.h
@@ -62,3 +62,12 @@ struct btd_attribute *btd_gatt_add_service(const bt_uuid_t *uuid);
*/
struct btd_attribute *btd_gatt_add_char(bt_uuid_t *uuid, uint8_t properties,
btd_attr_read_t read_cb);
+
+/* btd_gatt_read_attribute - Read the value of an attribute.
+ * @attr: Attribute to be read.
+ * @result: Callback function to be called with the result.
+ * @user_data: Data to be passed to the result callback function.
+ */
+void btd_gatt_read_attribute(struct btd_attribute *attr,
+ btd_attr_read_result_t result,
+ void *user_data);
--
1.8.3.1
--
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