rename libavahi-core to avahi-core

git-svn-id: file:///home/lennart/svn/public/avahi/trunk@57 941a03a8-eaeb-0310-b9a0-b1bbd8fe43fe

1 files changed, 372 insertions, 0 deletions

diff --git a/avahi-core/cache.c b/avahi-core/cache.c
new file mode 100644
index 0000000..0307b8e
--- /dev/null
+++ b/avahi-core/cache.c
@@ -0,0 +1,372 @@
+/* $Id$ */
+
+/***
+  This file is part of avahi.
+ 
+  avahi is free software; you can redistribute it and/or modify it
+  under the terms of the GNU Lesser General Public License as
+  published by the Free Software Foundation; either version 2.1 of the
+  License, or (at your option) any later version.
+ 
+  avahi is distributed in the hope that it will be useful, but WITHOUT
+  ANY WARRANTY; without even the implied warranty of MERCHANTABILITY
+  or FITNESS FOR A PARTICULAR PURPOSE. See the GNU Lesser General
+  Public License for more details.
+ 
+  You should have received a copy of the GNU Lesser General Public
+  License along with avahi; if not, write to the Free Software
+  Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307
+  USA.
+***/
+
+#ifdef HAVE_CONFIG_H
+#include <config.h>
+#endif
+
+#include <string.h>
+
+#include "util.h"
+#include "cache.h"
+
+static void remove_entry(AvahiCache *c, AvahiCacheEntry *e) {
+    AvahiCacheEntry *t;
+
+    g_assert(c);
+    g_assert(e);
+
+/*     g_message("removing from cache: %p %p", c, e); */
+
+    /* Remove from hash table */
+    t = g_hash_table_lookup(c->hash_table, e->record->key);
+    AVAHI_LLIST_REMOVE(AvahiCacheEntry, by_key, t, e);
+    if (t)
+        g_hash_table_replace(c->hash_table, t->record->key, t);
+    else
+        g_hash_table_remove(c->hash_table, e->record->key);
+
+    /* Remove from linked list */
+    AVAHI_LLIST_REMOVE(AvahiCacheEntry, entry, c->entries, e);
+        
+    if (e->time_event)
+        avahi_time_event_queue_remove(c->server->time_event_queue, e->time_event);
+
+    avahi_subscription_notify(c->server, c->interface, e->record, AVAHI_SUBSCRIPTION_REMOVE);
+
+    avahi_record_unref(e->record);
+    
+    g_free(e);
+}
+
+AvahiCache *avahi_cache_new(AvahiServer *server, AvahiInterface *iface) {
+    AvahiCache *c;
+    g_assert(server);
+
+    c = g_new(AvahiCache, 1);
+    c->server = server;
+    c->interface = iface;
+    c->hash_table = g_hash_table_new((GHashFunc) avahi_key_hash, (GEqualFunc) avahi_key_equal);
+
+    AVAHI_LLIST_HEAD_INIT(AvahiCacheEntry, c->entries);
+    
+    return c;
+}
+
+void avahi_cache_free(AvahiCache *c) {
+    g_assert(c);
+
+    while (c->entries)
+        remove_entry(c, c->entries);
+    
+    g_hash_table_destroy(c->hash_table);
+    
+    g_free(c);
+}
+
+AvahiCacheEntry *avahi_cache_lookup_key(AvahiCache *c, AvahiKey *k) {
+    g_assert(c);
+    g_assert(k);
+
+    g_assert(!avahi_key_is_pattern(k));
+    
+    return g_hash_table_lookup(c->hash_table, k);
+}
+
+gpointer avahi_cache_walk(AvahiCache *c, AvahiKey *pattern, AvahiCacheWalkCallback cb, gpointer userdata) {
+    gpointer ret;
+    
+    g_assert(c);
+    g_assert(pattern);
+    g_assert(cb);
+    
+    if (avahi_key_is_pattern(pattern)) {
+        AvahiCacheEntry *e, *n;
+        
+        for (e = c->entries; e; e = n) {
+            n = e->entry_next;
+            
+            if (avahi_key_pattern_match(pattern, e->record->key))
+                if ((ret = cb(c, pattern, e, userdata)))
+                    return ret;
+        }
+        
+    } else {
+        AvahiCacheEntry *e, *n;
+
+        for (e = avahi_cache_lookup_key(c, pattern); e; e = n) {
+            n = e->by_key_next;
+                
+            if ((ret = cb(c, pattern, e, userdata)))
+                return ret;
+        }
+    }
+
+    return NULL;
+}
+
+static gpointer lookup_record_callback(AvahiCache *c, AvahiKey *pattern, AvahiCacheEntry *e, void *userdata) {
+    g_assert(c);
+    g_assert(pattern);
+    g_assert(e);
+
+    if (avahi_record_equal_no_ttl(e->record, userdata))
+        return e;
+
+    return NULL;
+}
+
+AvahiCacheEntry *avahi_cache_lookup_record(AvahiCache *c, AvahiRecord *r) {
+    g_assert(c);
+    g_assert(r);
+
+    return avahi_cache_walk(c, r->key, lookup_record_callback, r);
+}
+
+static void next_expiry(AvahiCache *c, AvahiCacheEntry *e, guint percent);
+
+static void elapse_func(AvahiTimeEvent *t, void *userdata) {
+    AvahiCacheEntry *e = userdata;
+    
+    g_assert(t);
+    g_assert(e);
+
+    if (e->state == AVAHI_CACHE_FINAL) {
+        remove_entry(e->cache, e);
+        g_message("Removing entry from cache due to expiration");
+    } else {
+        guint percent = 0;
+    
+        switch (e->state) {
+            case AVAHI_CACHE_VALID:
+                e->state = AVAHI_CACHE_EXPIRY1;
+                percent = 85;
+                break;
+                
+            case AVAHI_CACHE_EXPIRY1:
+                e->state = AVAHI_CACHE_EXPIRY2;
+                percent = 90;
+                break;
+            case AVAHI_CACHE_EXPIRY2:
+                e->state = AVAHI_CACHE_EXPIRY3;
+                percent = 95;
+                break;
+                
+            case AVAHI_CACHE_EXPIRY3:
+                e->state = AVAHI_CACHE_FINAL;
+                percent = 100;
+                break;
+
+            default:
+                ;
+        }
+
+        g_assert(percent > 0);
+
+        g_message("Requesting cache entry update at %i%%.", percent);
+
+        /* Request a cache update, if we are subscribed to this entry */
+        if (avahi_is_subscribed(e->cache->server, e->record->key))
+            avahi_interface_post_query(e->cache->interface, e->record->key, TRUE);
+
+        /* Check again later */
+        next_expiry(e->cache, e, percent);
+    }
+}
+
+static void update_time_event(AvahiCache *c, AvahiCacheEntry *e) {
+    g_assert(c);
+    g_assert(e);
+    
+    if (e->time_event)
+        avahi_time_event_queue_update(c->server->time_event_queue, e->time_event, &e->expiry);
+    else
+        e->time_event = avahi_time_event_queue_add(c->server->time_event_queue, &e->expiry, elapse_func, e);
+}
+
+static void next_expiry(AvahiCache *c, AvahiCacheEntry *e, guint percent) {
+    gulong usec;
+
+    g_assert(c);
+    g_assert(e);
+    g_assert(percent > 0 && percent <= 100);
+
+    e->expiry = e->timestamp;
+
+    usec = e->record->ttl * 10000;
+
+    /* 2% jitter */
+    usec = g_random_int_range(usec*percent, usec*(percent+2));
+    
+    g_time_val_add(&e->expiry, usec);
+    update_time_event(c, e);
+}
+
+void avahi_cache_update(AvahiCache *c, AvahiRecord *r, gboolean unique, const AvahiAddress *a) {
+    AvahiCacheEntry *e, *t;
+    gchar *txt;
+    
+    g_assert(c);
+    g_assert(r && r->ref >= 1);
+
+    g_message("cache update: %s", (txt = avahi_record_to_string(r)));
+    g_free(txt);
+
+    if (r->ttl == 0) {
+
+        /* This is a goodbye request */
+
+        if ((e = avahi_cache_lookup_record(c, r))) {
+
+            e->state = AVAHI_CACHE_FINAL;
+            g_get_current_time(&e->timestamp);
+            e->expiry = e->timestamp;
+            g_time_val_add(&e->expiry, 1000000); /* 1s */
+            update_time_event(c, e);
+        }
+
+    } else {
+
+        /* This is an update request */
+
+        if ((t = e = avahi_cache_lookup_key(c, r->key))) {
+        
+            if (unique) {
+                
+                /* For unique records, remove all entries but one */
+                while (e->by_key_next)
+                    remove_entry(c, e->by_key_next);
+                
+            } else {
+                
+                /* For non-unique record, look for exactly the same entry */
+                for (; e; e = e->by_key_next)
+                    if (avahi_record_equal_no_ttl(e->record, r))
+                        break;
+            }
+        }
+    
+        if (e) {
+            
+/*         g_message("found matching cache entry"); */
+            
+            /* We are the first in the linked list so let's replace the hash table key with the new one */
+            if (e->by_key_prev == NULL)
+                g_hash_table_replace(c->hash_table, r->key, e);
+            
+            /* Notify subscribers */
+            if (!avahi_record_equal_no_ttl(e->record, r))
+                avahi_subscription_notify(c->server, c->interface, r, AVAHI_SUBSCRIPTION_CHANGE);    
+            
+            /* Update the record */
+            avahi_record_unref(e->record);
+            e->record = avahi_record_ref(r);
+            
+        } else {
+            /* No entry found, therefore we create a new one */
+            
+/*         g_message("couldn't find matching cache entry"); */
+            
+            e = g_new(AvahiCacheEntry, 1);
+            e->cache = c;
+            e->time_event = NULL;
+            e->record = avahi_record_ref(r);
+
+            /* Append to hash table */
+            AVAHI_LLIST_PREPEND(AvahiCacheEntry, by_key, t, e);
+            g_hash_table_replace(c->hash_table, e->record->key, t);
+
+            /* Append to linked list */
+            AVAHI_LLIST_PREPEND(AvahiCacheEntry, entry, c->entries, e);
+
+            /* Notify subscribers */
+            avahi_subscription_notify(c->server, c->interface, e->record, AVAHI_SUBSCRIPTION_NEW);
+        } 
+        
+        e->origin = *a;
+        g_get_current_time(&e->timestamp);
+        next_expiry(c, e, 80);
+        e->state = AVAHI_CACHE_VALID;
+    }
+}
+
+static gpointer drop_key_callback(AvahiCache *c, AvahiKey *pattern, AvahiCacheEntry *e, gpointer userdata) {
+    g_assert(c);
+    g_assert(pattern);
+    g_assert(e);
+
+    remove_entry(c, e);
+    return NULL;
+}
+
+void avahi_cache_drop_key(AvahiCache *c, AvahiKey *k) {
+    g_assert(c);
+    g_assert(k);
+
+    avahi_cache_walk(c, k, drop_key_callback, NULL);
+}
+
+void avahi_cache_drop_record(AvahiCache *c, AvahiRecord *r) {
+    AvahiCacheEntry *e;
+    
+    g_assert(c);
+    g_assert(r);
+
+    if ((e = avahi_cache_lookup_record(c, r))) 
+        remove_entry(c, e);
+}
+
+static void func(gpointer key, gpointer data, gpointer userdata) {
+    AvahiCacheEntry *e = data;
+    AvahiKey *k = key;
+    gchar *t;
+
+    g_assert(k);
+    g_assert(e);
+    
+    t = avahi_record_to_string(e->record);
+    fprintf((FILE*) userdata, "%s\n", t);
+    g_free(t);
+}
+
+void avahi_cache_dump(AvahiCache *c, FILE *f) {
+    g_assert(c);
+    g_assert(f);
+
+    fprintf(f, ";;; CACHE DUMP FOLLOWS ;;;\n");
+    g_hash_table_foreach(c->hash_table, func, f);
+}
+
+gboolean avahi_cache_entry_half_ttl(AvahiCache *c, AvahiCacheEntry *e) {
+    GTimeVal now;
+    guint age;
+    
+    g_assert(c);
+    g_assert(e);
+
+    g_get_current_time(&now);
+
+    age = avahi_timeval_diff(&now, &e->timestamp)/1000000;
+
+    g_message("age: %u, ttl/2: %u", age, e->record->ttl);
+    
+    return age >= e->record->ttl/2;
+}