From d8f7de1b16ff7e68f7dd9464243efbdc547063fa Mon Sep 17 00:00:00 2001
From: Takashi Iwai <tiwai@suse.de>
Date: Mon, 14 Feb 2005 15:09:09 +0000
Subject: [PATCH] Support dl-object cache

Added the support of dl-object caches for PCM plugins.
---
 include/local.h      |  5 ++++
 include/pcm_ioplug.h |  3 ++
 src/conf.c           |  4 +++
 src/dlmisc.c         | 68 ++++++++++++++++++++++++++++++++++++++++++++
 src/pcm/pcm.c        | 16 +++++++++--
 5 files changed, 93 insertions(+), 3 deletions(-)

diff --git a/include/local.h b/include/local.h
index 6df4abca..61ec10d8 100644
--- a/include/local.h
+++ b/include/local.h
@@ -232,4 +232,9 @@ static inline int snd_open_device(const char *filename, int fmode)
 #define snd_open_device(filename, fmode) open(filename, fmode);
 #endif
 
+/* dlobj cache */
+void *snd_dlobj_cache_lookup(const char *name);
+int snd_dlobj_cache_add(const char *name, void *dlobj, void *open_func);
+void snd_dlobj_cache_cleanup(void);
+
 #endif
diff --git a/include/pcm_ioplug.h b/include/pcm_ioplug.h
index 62c064ac..03b0540b 100644
--- a/include/pcm_ioplug.h
+++ b/include/pcm_ioplug.h
@@ -37,10 +37,13 @@ enum {
 typedef struct snd_pcm_ioplug snd_pcm_ioplug_t;
 typedef struct snd_pcm_ioplug_callback snd_pcm_ioplug_callback_t;
 
+#define SND_PCM_IOPLUG_FLAG_LISTED	(1<<0)
+
 /* exported pcm data */
 struct snd_pcm_ioplug {
 	/* must be filled before calling snd_pcm_ioplug_create() */
 	const char *name;
+	unsigned int flags;	/* SND_PCM_IOPLUG_FLAG_XXX */
 	int poll_fd;
 	unsigned int poll_events;
 	unsigned int mmap_rw;		/* pseudo mmap */
diff --git a/src/conf.c b/src/conf.c
index 066e07e1..26007832 100644
--- a/src/conf.c
+++ b/src/conf.c
@@ -3113,6 +3113,10 @@ int snd_config_update_free_global(void)
 		snd_config_update_free(snd_config_global_update);
 	snd_config_global_update = NULL;
 	pthread_mutex_unlock(&snd_config_update_mutex);
+
+	/* FIXME: better to place this in another place... */
+	snd_dlobj_cache_cleanup();
+
 	return 0;
 }
 
diff --git a/src/dlmisc.c b/src/dlmisc.c
index a5d174d7..6298e483 100644
--- a/src/dlmisc.c
+++ b/src/dlmisc.c
@@ -29,6 +29,7 @@
 
 #define _GNU_SOURCE
 #include <dlfcn.h>
+#include "list.h"
 #include "local.h"
 
 #ifndef DOC_HIDDEN
@@ -143,3 +144,70 @@ void *snd_dlsym(void *handle, const char *name, const char *version)
 		return NULL;
 	return dlsym(handle, name);
 }
+
+/*
+ * dlobj cache
+ *
+ * FIXME: add reference counter and proper locking
+ */
+
+struct dlobj_cache {
+	const char *name;
+	void *obj;
+	void *func;
+	struct list_head list;
+};
+
+static LIST_HEAD(pcm_dlobj_list);
+
+void *snd_dlobj_cache_lookup(const char *name)
+{
+	struct list_head *p;
+	struct dlobj_cache *c;
+
+	list_for_each(p, &pcm_dlobj_list) {
+		c = list_entry(p, struct dlobj_cache, list);
+		if (strcmp(c->name, name) == 0)
+			return c->func;
+	}
+	return NULL;
+}
+
+int snd_dlobj_cache_add(const char *name, void *dlobj, void *open_func)
+{
+	struct list_head *p;
+	struct dlobj_cache *c;
+
+	list_for_each(p, &pcm_dlobj_list) {
+		c = list_entry(p, struct dlobj_cache, list);
+		if (strcmp(c->name, name) == 0)
+			return 0; /* already exists */
+	}
+	c = malloc(sizeof(*c));
+	if (! c)
+		return -ENOMEM;
+	c->name = strdup(name);
+	if (! c->name) {
+		free(c);
+		return -ENOMEM;
+	}
+	c->obj = dlobj;
+	c->func = open_func;
+	list_add_tail(&c->list, &pcm_dlobj_list);
+	return 0;
+}
+
+void snd_dlobj_cache_cleanup(void)
+{
+	struct list_head *p;
+	struct dlobj_cache *c;
+
+	while (! list_empty(&pcm_dlobj_list)) {
+		p = pcm_dlobj_list.next;
+		c = list_entry(p, struct dlobj_cache, list);
+		list_del(p);
+		snd_dlclose(c->obj);
+		free(c->name);
+		free(c);
+	}
+}
diff --git a/src/pcm/pcm.c b/src/pcm/pcm.c
index a4df4698..c2fc9547 100644
--- a/src/pcm/pcm.c
+++ b/src/pcm/pcm.c
@@ -2019,6 +2019,11 @@ static int snd_pcm_open_conf(snd_pcm_t **pcmp, const char *name,
 #ifndef PIC
 	snd_pcm_open_symbols();	/* this call is for static linking only */
 #endif
+	open_func = snd_dlobj_cache_lookup(open_name);
+	if (open_func) {
+		err = 0;
+		goto _err;
+	}
 	h = snd_dlopen(lib, RTLD_NOW);
 	if (h)
 		open_func = snd_dlsym(h, open_name, SND_DLSYM_VERSION(SND_PCM_DLSYM_VERSION));
@@ -2032,17 +2037,22 @@ static int snd_pcm_open_conf(snd_pcm_t **pcmp, const char *name,
 		err = -ENXIO;
 	}
        _err:
-	if (type_conf)
-		snd_config_delete(type_conf);
 	if (err >= 0) {
 		err = open_func(pcmp, name, pcm_root, pcm_conf, stream, mode);
 		if (err >= 0) {
+			if (h /*&& (mode & SND_PCM_KEEP_ALIVE)*/) {
+				snd_dlobj_cache_add(open_name, h, open_func);
+				h = NULL;
+			}
 			(*pcmp)->dl_handle = h;
 			err = 0;
 		} else {
-			snd_dlclose(h);
+			if (h)
+				snd_dlclose(h);
 		}
 	}
+	if (type_conf)
+		snd_config_delete(type_conf);
 	if (buf)
 		free(buf);
 	if (buf1)
-- 
2.47.1