X-Git-Url: http://git.tuebingen.mpg.de/?p=paraslash.git;a=blobdiff_plain;f=filter_common.c;h=b406951e8ff145542e9ad579bde5311b7e3be1aa;hp=5a5e9d037a96ce1e8db44ae9f60964688ae8a5f5;hb=e79198e9851faddfd64e47654b5bc66fbc574255;hpb=4adde8dae3317fa83b81e7a860c9ed9133e99bb0

diff --git a/filter_common.c b/filter_common.c
index 5a5e9d03..b406951e 100644
--- a/filter_common.c
+++ b/filter_common.c
@@ -28,15 +28,15 @@
  *
  * \param filter_num Between zero and NUM_SUPPORTED_FILTERS, inclusively.
  *
- * \return Pointer to the filter identified by the given filter number.
+ * \return Pointer to the filter identified by the given filter number, or
+ * NULL if the filter number is out of range.
  *
- * It is a fatal error if the given number is out of range. In this case
- * the function aborts.
+ * \sa filter_name().
  */
 const struct filter *filter_get(int filter_num)
 {
-	assert(filter_num >= 1);
-	assert(filter_num <= LSG_NUM_FILTER_CMD_SUBCOMMANDS);
+	if (filter_num < 1 || filter_num > LSG_NUM_FILTER_CMD_SUBCOMMANDS)
+		return NULL;
 	return lls_user_data(FILTER_CMD(filter_num));
 }
 
@@ -45,8 +45,18 @@ static inline bool filter_supported(int filter_num)
 	return lls_user_data(FILTER_CMD(filter_num));
 }
 
+/**
+ * Return the name of a filter, given its number.
+ *
+ * \param filter_num See \ref filter_get().
+ *
+ * \return A pointer to a string literal, or NULL if filter_num is out of
+ * range. The caller must not attempt to call free(3) on the returned pointer.
+ */
 const char *filter_name(int filter_num)
 {
+	if (filter_num < 1 || filter_num > LSG_NUM_FILTER_CMD_SUBCOMMANDS)
+		return NULL;
 	return lls_command_name(FILTER_CMD(filter_num));
 }
 
@@ -142,6 +152,26 @@ void print_filter_helps(bool detailed)
 	}
 }
 
+/**
+ * Print a short summary of all available filters to stdout.
+ *
+ * For each supported filter, the filter name and the purpose text is printed
+ * in a single line. Since no options are shown, the filter list is more
+ * concise than the text obtained from print_filter_helps().
+ */
+void print_filter_list(void)
+{
+	int i;
+
+	printf("Available filters:\n");
+	FOR_EACH_FILTER(i) {
+		const struct lls_command *cmd = FILTER_CMD(i);
+		if (!filter_supported(i))
+			continue;
+		printf("%-9s %s\n", filter_name(i), lls_purpose(cmd));
+	}
+}
+
 /**
  * Set select timeout of the scheduler.
  *