write: Improve help text of --writer.

[paraslash.git] / filter_common.c

diff --git a/filter_common.c b/filter_common.c
index 8ce66ea878c309d96e98e944f21af02670d9060c..6fb9bd96ef8278b3e328198e24db78664a956542 100644 (file)
--- a/filter_common.c
+++ b/filter_common.c
@@ -1,5 +1,5 @@
 /*
- * Copyright (C) 2005-2014 Andre Noll <maan@systemlinux.org>
+ * Copyright (C) 2005 Andre Noll <maan@tuebingen.mpg.de>
  *
  * Licensed under the GPL v2. For licencing details see COPYING.
  */
@@ -19,8 +19,28 @@
 #include "error.h"
 #include "string.h"
 
+/** Iterate over the array of supported filters. */
+#define FOR_EACH_SUPPORTED_FILTER(j)  for (j = 0; j < NUM_SUPPORTED_FILTERS; j++)
+
 /** The array of supported filters. */
-struct filter filters[NUM_SUPPORTED_FILTERS] = {FILTER_ARRAY};
+static struct filter filters[NUM_SUPPORTED_FILTERS] = {FILTER_ARRAY};
+
+/**
+ * Obtain a reference to a filter structure.
+ *
+ * \param filter_num Between zero and NUM_SUPPORTED_FILTERS, inclusively.
+ *
+ * \return Pointer to the filter identified by the given filter number.
+ *
+ * It is a fatal error if the given number is out of range. In this case
+ * the function aborts.
+ */
+const struct filter *filter_get(int filter_num)
+{
+       assert(filter_num >= 0);
+       assert(filter_num < NUM_SUPPORTED_FILTERS);
+       return filters + filter_num;
+}
 
 /**
  * Call the init function of each supported filter.
@@ -31,7 +51,7 @@ void filter_init(void)
        int i;
 
        FOR_EACH_SUPPORTED_FILTER(i)
-               filters[i].init(filters + i);
+               filter_get(i)->init((struct filter *)filter_get(i));
 }
 
 /*
@@ -40,7 +60,7 @@ void filter_init(void)
  */
 static int parse_filter_args(int filter_num, char *options, void **conf)
 {
-       struct filter *f = &filters[filter_num];
+       const struct filter *f = filter_get(filter_num);
        int ret, argc;
        char **argv;
 
@@ -80,7 +100,7 @@ int check_filter_arg(char *fa, void **conf)
        *conf = NULL;
 //     PARA_DEBUG_LOG("arg: %s\n", fa);
        FOR_EACH_SUPPORTED_FILTER(j) {
-               const char *name = filters[j].name;
+               const char *name = filter_get(j)->name;
                size_t len = strlen(name);
                char c;
                if (strlen(fa) < len)
@@ -90,7 +110,7 @@ int check_filter_arg(char *fa, void **conf)
                c = fa[len];
                if (c && c != ' ')
                        continue;
-               if (c && !filters[j].parse_config)
+               if (c && !filter_get(j)->parse_config)
                        return -E_BAD_FILTER_OPTIONS;
                return parse_filter_args(j, c? fa + len + 1 :
                        fa + strlen(fa), conf);
@@ -113,12 +133,12 @@ void print_filter_helps(unsigned flags)
                        printf_or_die("\n                  ");
                        num = 0;
                }
-               num += printf_or_die("%s%s", i? " " : "", filters[i].name);
+               num += printf_or_die("%s%s", i? " " : "", filter_get(i)->name);
        }
        printf_or_die("\n");
 
        FOR_EACH_SUPPORTED_FILTER(i) {
-               struct filter *f = filters + i;
+               struct filter *f = (struct filter *)filter_get(i);
 
                if (!f->help.short_help)
                        continue;
@@ -132,18 +152,17 @@ void print_filter_helps(unsigned flags)
  * Set select timeout of the scheduler.
  *
  * \param s The scheduler.
- * \param t The task struct of this filter.
+ * \param context Pointer to the filter node (task context).
  *
  * This looks at the status of the btr node of the filter. If data is available
  * in the input queue of the filter, or if an error occurred, a minimal timeout
  * for the next select call is requested from the scheduler. Otherwise the
  * scheduler timeout is left unchanged.
  */
-void generic_filter_pre_select(struct sched *s, struct task *t)
+void generic_filter_pre_select(struct sched *s, void *context)
 {
-       struct filter_node *fn = container_of(t, struct filter_node, task);
+       struct filter_node *fn = context;
 
-       t->error = 0;
        if (btr_node_status(fn->btrn, fn->min_iqs, BTR_NT_INTERNAL) != 0)
                sched_min_delay(s);
 }