Add sr_spew/SR_LOG_SPEW for even more debug output.

This is meant for really extensive debug output which can slow down
operation significantly and should thus only be enabled if really needed.

log.c

@@ -32,12 +32,12 @@ static int sr_loglevel = SR_LOG_WARN; /* Show errors+warnings per default. */
  * and so on) libsigrok will output. Using SR_LOG_NONE disables all messages.
  *
  * @param loglevel The loglevel to set (SR_LOG_NONE, SR_LOG_ERR, SR_LOG_WARN,
- *                 SR_LOG_INFO, or SR_LOG_DBG).
+ *                 SR_LOG_INFO, SR_LOG_DBG, or SR_LOG_SPEW).
  * @return SR_OK upon success, SR_ERR_ARG upon invalid loglevel.
  */
 int sr_set_loglevel(int loglevel)
 {
-	if (loglevel < SR_LOG_NONE || loglevel > SR_LOG_DBG) {
+	if (loglevel < SR_LOG_NONE || loglevel > SR_LOG_SPEW) {
 		sr_err("log: %s: invalid loglevel %d", __func__, loglevel);
 		return SR_ERR_ARG;
 	}
@@ -85,6 +85,18 @@ int sr_log(int loglevel, const char *format, ...)
 	return ret;
 }
 
+int sr_spew(const char *format, ...)
+{
+	int ret;
+	va_list args;
+
+	va_start(args, format);
+	ret = sr_logv(SR_LOG_SPEW, format, args);
+	va_end(args);
+
+	return ret;
+}
+
 int sr_dbg(const char *format, ...)
 {
 	int ret;

sigrok-internal.h

@@ -42,6 +42,7 @@ int load_hwplugins(void);
 /*--- log.c -----------------------------------------------------------------*/
 
 int sr_log(int loglevel, const char *format, ...);
+int sr_spew(const char *format, ...);
 int sr_dbg(const char *format, ...);
 int sr_info(const char *format, ...);
 int sr_warn(const char *format, ...);

sigrok.h

@@ -73,6 +73,7 @@ extern "C" {
 #define SR_LOG_WARN	2
 #define SR_LOG_INFO	3
 #define SR_LOG_DBG	4
+#define SR_LOG_SPEW	5
 
 typedef int (*sr_receive_data_callback) (int fd, int revents, void *user_data);