hameg-hmo: Avoid getting stuck upon SCPI timeouts.

[libsigrok.git] / src / scpi / scpi.c

diff --git a/src/scpi/scpi.c b/src/scpi/scpi.c
index 62e81bebeedab94822786daa317a6d7151b8bdcf..2477cf2323971c314880c3bc235732fd076c0af3 100644 (file)
--- a/src/scpi/scpi.c
+++ b/src/scpi/scpi.c
@@ -100,7 +100,7 @@ static const struct sr_scpi_dev_inst *scpi_devs[] = {
 #ifdef HAVE_LIBGPIB
        &scpi_libgpib_dev,
 #endif
-#ifdef HAVE_LIBSERIALPORT
+#ifdef HAVE_SERIAL_COMM
        &scpi_serial_dev, /* Must be last as it matches any resource. */
 #endif
 };
@@ -407,6 +407,21 @@ SR_PRIV int sr_scpi_open(struct sr_scpi_dev_inst *scpi)
        return scpi->open(scpi);
 }
 
+/**
+ * Get the connection ID of the SCPI device.
+ *
+ * @param scpi Previously initialized SCPI device structure.
+ * @param connection_id Pointer where to store the connection ID. The caller
+ *        is responsible for g_free()ing the string when it is no longer needed.
+ *
+ * @return SR_OK on success, SR_ERR on failure.
+ */
+SR_PRIV int sr_scpi_connection_id(struct sr_scpi_dev_inst *scpi,
+               char **connection_id)
+{
+       return scpi->connection_id(scpi, connection_id);
+}
+
 /**
  * Add an event source for an SCPI device.
  *
@@ -946,6 +961,7 @@ SR_PRIV int sr_scpi_get_block(struct sr_scpi_dev_inst *scpi,
 {
        int ret;
        GString* response;
+       gsize oldlen;
        char buf[10];
        long llen;
        long datalen;
@@ -975,14 +991,14 @@ SR_PRIV int sr_scpi_get_block(struct sr_scpi_dev_inst *scpi,
        *scpi_response = NULL;
 
        /* Get (the first chunk of) the response. */
-       while (response->len < 2) {
+       do {
                ret = scpi_read_response(scpi, response, timeout);
                if (ret < 0) {
                        g_mutex_unlock(&scpi->scpi_mutex);
                        g_string_free(response, TRUE);
                        return ret;
                }
-       }
+       } while (response->len < 2);
 
        /*
         * SCPI protocol data blocks are preceeded with a length spec.
@@ -1029,25 +1045,33 @@ SR_PRIV int sr_scpi_get_block(struct sr_scpi_dev_inst *scpi,
        g_string_erase(response, 0, 2 + llen);
 
        /*
-        * If the initially assumed length does not cover the data block
-        * length, then re-allocate the buffer size to the now known
-        * length, and keep reading more chunks of response data.
+        * Re-allocate the buffer size to the now known length
+        * and keep reading more chunks of response data.
         */
-       if (response->len < (unsigned long)(datalen)) {
-               int oldlen = response->len;
-               g_string_set_size(response, datalen);
-               g_string_set_size(response, oldlen);
-       }
-
-       while (response->len < (unsigned long)(datalen)) {
-               ret = scpi_read_response(scpi, response, timeout);
-               if (ret < 0) {
-                       g_mutex_unlock(&scpi->scpi_mutex);
-                       g_string_free(response, TRUE);
-                       return ret;
-               }
-               if (ret > 0)
-                       timeout = g_get_monotonic_time() + scpi->read_timeout_us;
+       oldlen = response->len;
+       g_string_set_size(response, datalen);
+       g_string_set_size(response, oldlen);
+
+       if (oldlen < (unsigned long)(datalen)) {
+               do {
+                       oldlen = response->len;
+                       ret = scpi_read_response(scpi, response, timeout);
+
+                       /* On timeout truncate the buffer and send the partial response
+                        * instead of getting stuck on timeouts...
+                        */
+                       if (ret == SR_ERR_TIMEOUT) {
+                               datalen = oldlen;
+                               break;
+                       }
+                       if (ret < 0) {
+                               g_mutex_unlock(&scpi->scpi_mutex);
+                               g_string_free(response, TRUE);
+                               return ret;
+                       }
+                       if (ret > 0)
+                               timeout = g_get_monotonic_time() + scpi->read_timeout_us;
+               } while (response->len < (unsigned long)(datalen));
        }
 
        g_mutex_unlock(&scpi->scpi_mutex);