Re: [alsa-devel] [PATCH][RFC][alsa-utils 5/9] alsactl: use link list to maintain source of events

Dne 5.10.2018 v 16:47 Takashi Sakamoto napsal(a):

At present, handlers for control nodes are maintained by one-dimensional array. This is not necessarily useful to maintain handlers with associated information.

This commit adds link-list for the maintenance.

Thanks for the improved code.

Please, use macros in list.h to manage linked list which are inherited from the kernel here.

Jaroslav

Signed-off-by: Takashi Sakamoto o-takashi@sakamocchi.jp

alsactl/monitor.c | 84 +++++++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 84 insertions(+)

diff --git a/alsactl/monitor.c b/alsactl/monitor.c index cf5c50a..8b16307 100644 --- a/alsactl/monitor.c +++ b/alsactl/monitor.c @@ -29,6 +29,16 @@ static int signal_type; static bool interrupted;

+struct src_entry {

• snd_ctl_t *handle;
• char *name;
• unsigned int pfd_count;
• struct {

• struct src_entry *prev;
  

• struct src_entry *next;
  

• } list;

+};

#define MAX_CARDS 256

struct snd_card_iterator { @@ -59,6 +69,72 @@ static const char *snd_card_iterator_next(struct snd_card_iterator *iter) return (const char *)iter->name; }

+static inline void remove_source_entry(struct src_entry *src) +{

• struct src_entry *prev = src->list.prev;
• struct src_entry *next = src->list.next;
• if (prev)

• prev->list.next = src->list.next;
  

• if (next)

• next->list.prev = src->list.prev;
  

• free(src->name);
• free(src);

+}

+static void clear_source_list(struct src_entry **srcs) +{

• while (*srcs) {

• struct src_entry *src = *srcs;
  

• *srcs = src->list.next;
  

• remove_source_entry(src);
  

• }

+}

+static int insert_source_entry(struct src_entry **head, snd_ctl_t *handle,

• 	       const char *name)
  

+{

• struct src_entry *src;
• int count;
• int err;
• src = calloc(1, sizeof(*src));
• if (!src)

• return -ENOMEM;
  

• src->handle = handle;
• src->name = strdup(name);
• if (!src->name) {

• err = -ENOMEM;
  

• goto error;
  

• }
• count = snd_ctl_poll_descriptors_count(handle);
• if (count < 0) {

• err = count;
  

• goto error;
  

• }
• if (count == 0) {

• err = -ENXIO;
  

• goto error;
  

• }
• src->pfd_count = count;
• if (*head) {

• src->list.next = (*head)->list.next;
  

• src->list.prev = *head;
  

• (*head)->list.next = src;
  

• } else {

• *head = src;
  

• }
• return 0;

+error:

• free(src);
• return err;

+}

static int open_ctl(const char *name, snd_ctl_t **ctlp) { snd_ctl_t *ctl; @@ -259,6 +335,7 @@ static int prepare_signal_handler(void)

int monitor(const char *name) {

• struct src_entry *srcs = NULL; snd_ctl_t *ctls[MAX_CARDS] = {0}; int ncards = 0; int show_cards;

@@ -281,6 +358,9 @@ int monitor(const char *name) snd_card_iterator_init(&iter); while ((cardname = snd_card_iterator_next(&iter))) { err = open_ctl(cardname, &ctls[ncards]);

• 	if (err < 0)
  

• 		goto error;
  

• 	err = insert_source_entry(&srcs, ctls[ncards], cardname);
  if (err < 0)
  	goto error;
  ++ncards;
  

@@ -288,6 +368,9 @@ int monitor(const char *name) show_cards = 1; } else { err = open_ctl(name, &ctls[0]);

• if (err < 0)
  

• 	goto error;
  

• err = insert_source_entry(&srcs, ctls[ncards], name);
  

  if (err < 0) goto error; ncards++;

@@ -300,6 +383,7 @@ int monitor(const char *name) clear_dispatcher(epfd, ctls, ncards);

error:

• clear_source_list(&srcs); for (i = 0; i < ncards; i++) { if (ctls[i]) snd_ctl_close(ctls[i]);