i3bar: properly restart status command after config change

RELEASE-NOTES-next

@@ -25,3 +25,4 @@ strongly encouraged to upgrade.
   • fix duplicate bindcode after i3-config-wizard
   • clear pixmap before drawing to prevent visual grabage in clients using 'Shape'
   • i3bar: properly close file descriptors
+  • i3bar: properly restart status command after config change

i3bar/include/child.h

@@ -42,6 +42,12 @@ typedef struct {
     bool click_events_init;
 } i3bar_child;
 
+/*
+ * Remove all blocks from the given statusline.
+ * If free_resources is set, the fields of each status block will be free'd.
+ */
+void clear_statusline(struct statusline_head *head, bool free_resources);
+
 /*
  * Start a child process with the specified command and reroute stdin.
  * We actually start a $SHELL to execute the command so we don't have to care

i3bar/src/child.c

@@ -27,7 +27,7 @@
 #include <yajl/yajl_parse.h>
 
 /* Global variables for child_*() */
-i3bar_child child;
+i3bar_child child = {0};
 #define DLOG_CHILD DLOG("%s: pid=%ld stopped=%d stop_signal=%d cont_signal=%d click_events=%d click_events_init=%d\n", \
                         __func__, (long)child.pid, child.stopped, child.stop_signal, child.cont_signal, child.click_events, child.click_events_init)
 
@@ -66,7 +66,7 @@ int child_stdin;
  * Remove all blocks from the given statusline.
  * If free_resources is set, the fields of each status block will be free'd.
  */
-static void clear_statusline(struct statusline_head *head, bool free_resources) {
+void clear_statusline(struct statusline_head *head, bool free_resources) {
     struct status_block *first;
     while (!TAILQ_EMPTY(head)) {
         first = TAILQ_FIRST(head);

i3bar/src/config.c

@@ -184,7 +184,6 @@ static int config_string_cb(void *params_, const unsigned char *val, size_t _len
 
     if (!strcmp(cur_key, "status_command")) {
         DLOG("command = %.*s\n", len, val);
-        FREE(config.command);
         sasprintf(&config.command, "%.*s", len, val);
         return 1;
     }

i3bar/src/ipc.c

@@ -170,6 +170,15 @@ static void got_mode_event(char *event) {
     draw_bars(false);
 }
 
+static bool strings_differ(char *a, char *b) {
+    const bool a_null = (a == NULL);
+    const bool b_null = (b == NULL);
+    if (a_null != b_null) {
+        return true;
+    }
+    return strcmp(a, b) != 0;
+}
+
 /*
  * Called, when a barconfig_update event arrives (i.e. i3 changed the bar hidden_state or mode)
  *
@@ -190,8 +199,11 @@ static void got_bar_config_update(char *event) {
 
     /* update the configuration with the received settings */
     DLOG("Received bar config update \"%s\"\n", event);
-    char *old_command = config.command ? sstrdup(config.command) : NULL;
+
+    char *old_command = config.command;
+    config.command = NULL;
     bar_display_mode_t old_mode = config.hide_on_modifier;
+
     parse_config_json(event);
     if (old_mode != config.hide_on_modifier) {
         reconfig_windows(true);
@@ -202,8 +214,9 @@ static void got_bar_config_update(char *event) {
     init_colors(&(config.colors));
 
     /* restart status command process */
-    if (old_command && strcmp(old_command, config.command) != 0) {
+    if (strings_differ(old_command, config.command)) {
         kill_child();
+        clear_statusline(&statusline_head, true);
         start_child(config.command);
     }
     free(old_command);