Hi Lukasz,
On Tue, Apr 29, 2014, Lukasz Rymanowski wrote:
> +static void gatt_request_complete(void *data, const uint8_t *pdu, uint16_t len)
> +{
> + struct req_data *d = data;
> +
> + if (pdu)
> + g_attrib_send(d->dev->attrib, 0, pdu, len, NULL, NULL, NULL);
> + else
> + error("gatt: gatt_request_complete: pdu not present ?!");
> +
> + free(d);
> +}
> +
> +static uint8_t read_request(const uint8_t *cmd, uint16_t cmd_len,
> + struct gatt_device *dev)
> +{
> + uint16_t handle;
> + uint16_t len;
> + uint16_t offset = 0;
> + struct req_data *req_data;
> +
> + DBG("");
> +
> + req_data = new0(struct req_data, 1);
> + if (!req_data)
> + return ATT_ECODE_INSUFF_RESOURCES;
> +
> + switch (cmd[0]) {
> + case ATT_OP_READ_BLOB_REQ:
> + len = dec_read_blob_req(cmd, cmd_len, &handle, &offset);
> + if (!len) {
> + free(req_data);
> + return ATT_ECODE_INVALID_PDU;
> + }
> + req_data->long_read = true;
> + break;
> + case ATT_OP_READ_REQ:
> + len = dec_read_req(cmd, cmd_len, &handle);
> + if (!len) {
> + free(req_data);
> + return ATT_ECODE_INVALID_PDU;
> + }
> + break;
> + default:
> + error("gatt: Unexpected read type 0x%02x", cmd[0]);
> + free(req_data);
> + return ATT_ECODE_REQ_NOT_SUPP;
> + }
> +
> + req_data->dev = dev;
> + req_data->opcode = cmd[0];
> +
> + if (!gatt_db_read(gatt_db, handle, offset, req_data, gatt_request_complete)) {
> + free(req_data);
> + return ATT_ECODE_UNLIKELY;
> + }
I don't understand the need to have so many levels of callback passing
instead of having simple direct calls, especially since all functions
are in the same c-file anyway. I.e. why can't the characteristic
read/write callbacks be responsible themselves for sending the response
PDU (if that's all your gatt_request_complete function is needed for).
This passing a callback (gatt_request_complete in this case) as a
parameter to another callback (the read/write callback) doesn't really
help in keeping things simple and understandable.
Johan
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