s3-memcache: update memcache to use new DLIST macros

[abartlet/samba.git/.git] / source3 / lib / memcache.c

diff --git a/source3/lib/memcache.c b/source3/lib/memcache.c
index 17630066ae2a395dceccb8881692cfe8c6216f15..5c4bafa17d075c8bee7b99dd323c488c8a2428dc 100644 (file)
--- a/source3/lib/memcache.c
+++ b/source3/lib/memcache.c
@@ -18,7 +18,9 @@
 */
 
 #include "memcache.h"
-#include "rbtree.h"
+#include "../lib/util/rbtree.h"
+
+static struct memcache *global_cache;
 
 struct memcache_element {
        struct rb_node rb_node;
@@ -29,12 +31,33 @@ struct memcache_element {
 };
 
 struct memcache {
-       struct memcache_element *mru, *lru;
+       struct memcache_element *mru;
        struct rb_root tree;
        size_t size;
        size_t max_size;
 };
 
+static void memcache_element_parse(struct memcache_element *e,
+                                  DATA_BLOB *key, DATA_BLOB *value);
+
+static bool memcache_is_talloc(enum memcache_number n)
+{
+       bool result;
+
+       switch (n) {
+       case GETPWNAM_CACHE:
+       case PDB_GETPWSID_CACHE:
+       case SINGLETON_CACHE_TALLOC:
+               result = true;
+               break;
+       default:
+               result = false;
+               break;
+       }
+
+       return result;
+}
+
 static int memcache_destructor(struct memcache *cache) {
        struct memcache_element *e, *next;
 
@@ -58,6 +81,12 @@ struct memcache *memcache_init(TALLOC_CTX *mem_ctx, size_t max_size)
        return result;
 }
 
+void memcache_set_global(struct memcache *cache)
+{
+       TALLOC_FREE(global_cache);
+       global_cache = cache;
+}
+
 static struct memcache_element *memcache_node2elem(struct rb_node *node)
 {
        return (struct memcache_element *)
@@ -83,11 +112,11 @@ static int memcache_compare(struct memcache_element *e, enum memcache_number n,
 {
        DATA_BLOB this_key, this_value;
 
-       if ((int)e->n < (int)n) return -1;
-       if ((int)e->n > (int)n) return 1;
+       if ((int)e->n < (int)n) return 1;
+       if ((int)e->n > (int)n) return -1;
 
-       if (e->keylength < key.length) return -1;
-       if (e->keylength > key.length) return 1;
+       if (e->keylength < key.length) return 1;
+       if (e->keylength > key.length) return -1;
 
        memcache_element_parse(e, &this_key, &this_value);
        return memcmp(this_key.data, key.data, key.length);
@@ -119,38 +148,62 @@ bool memcache_lookup(struct memcache *cache, enum memcache_number n,
 {
        struct memcache_element *e;
 
+       if (cache == NULL) {
+               cache = global_cache;
+       }
+       if (cache == NULL) {
+               return false;
+       }
+
        e = memcache_find(cache, n, key);
        if (e == NULL) {
                return false;
        }
 
        if (cache->size != 0) {
-               /*
-                * Do LRU promotion only when we will ever shrink
-                */
-               if (e == cache->lru) {
-                       cache->lru = e->prev;
-               }
                DLIST_PROMOTE(cache->mru, e);
-               if (cache->mru == NULL) {
-                       cache->mru = e;
-               }
        }
 
        memcache_element_parse(e, &key, value);
        return true;
 }
 
+void *memcache_lookup_talloc(struct memcache *cache, enum memcache_number n,
+                            DATA_BLOB key)
+{
+       DATA_BLOB value;
+       void *result;
+
+       if (!memcache_lookup(cache, n, key, &value)) {
+               return NULL;
+       }
+
+       if (value.length != sizeof(result)) {
+               return NULL;
+       }
+
+       memcpy(&result, value.data, sizeof(result));
+
+       return result;
+}
+
 static void memcache_delete_element(struct memcache *cache,
                                    struct memcache_element *e)
 {
        rb_erase(&e->rb_node, &cache->tree);
 
-       if (e == cache->lru) {
-               cache->lru = e->prev;
-       }
        DLIST_REMOVE(cache->mru, e);
 
+       if (memcache_is_talloc(e->n)) {
+               DATA_BLOB cache_key, cache_value;
+               void *ptr;
+
+               memcache_element_parse(e, &cache_key, &cache_value);
+               SMB_ASSERT(cache_value.length == sizeof(ptr));
+               memcpy(&ptr, cache_value.data, sizeof(ptr));
+               TALLOC_FREE(ptr);
+       }
+
        cache->size -= memcache_element_size(e->keylength, e->valuelength);
 
        SAFE_FREE(e);
@@ -162,8 +215,8 @@ static void memcache_trim(struct memcache *cache)
                return;
        }
 
-       while ((cache->size > cache->max_size) && (cache->lru != NULL)) {
-               memcache_delete_element(cache, cache->lru);
+       while ((cache->size > cache->max_size) && DLIST_TAIL(cache->mru)) {
+               memcache_delete_element(cache, DLIST_TAIL(cache->mru));
        }
 }
 
@@ -172,6 +225,13 @@ void memcache_delete(struct memcache *cache, enum memcache_number n,
 {
        struct memcache_element *e;
 
+       if (cache == NULL) {
+               cache = global_cache;
+       }
+       if (cache == NULL) {
+               return;
+       }
+
        e = memcache_find(cache, n, key);
        if (e == NULL) {
                return;
@@ -189,6 +249,13 @@ void memcache_add(struct memcache *cache, enum memcache_number n,
        DATA_BLOB cache_key, cache_value;
        size_t element_size;
 
+       if (cache == NULL) {
+               cache = global_cache;
+       }
+       if (cache == NULL) {
+               return;
+       }
+
        if (key.length == 0) {
                return;
        }
@@ -199,6 +266,12 @@ void memcache_add(struct memcache *cache, enum memcache_number n,
                memcache_element_parse(e, &cache_key, &cache_value);
 
                if (value.length <= cache_value.length) {
+                       if (memcache_is_talloc(e->n)) {
+                               void *ptr;
+                               SMB_ASSERT(cache_value.length == sizeof(ptr));
+                               memcpy(&ptr, cache_value.data, sizeof(ptr));
+                               TALLOC_FREE(ptr);
+                       }
                        /*
                         * We can reuse the existing record
                         */
@@ -246,18 +319,39 @@ void memcache_add(struct memcache *cache, enum memcache_number n,
        rb_insert_color(&e->rb_node, &cache->tree);
 
        DLIST_ADD(cache->mru, e);
-       if (cache->lru == NULL) {
-               cache->lru = e;
-       }
 
        cache->size += element_size;
        memcache_trim(cache);
 }
 
+void memcache_add_talloc(struct memcache *cache, enum memcache_number n,
+                        DATA_BLOB key, void *pptr)
+{
+       void **ptr = (void **)pptr;
+       void *p;
+
+       if (cache == NULL) {
+               cache = global_cache;
+       }
+       if (cache == NULL) {
+               return;
+       }
+
+       p = talloc_move(cache, ptr);
+       memcache_add(cache, n, key, data_blob_const(&p, sizeof(p)));
+}
+
 void memcache_flush(struct memcache *cache, enum memcache_number n)
 {
        struct rb_node *node;
 
+       if (cache == NULL) {
+               cache = global_cache;
+       }
+       if (cache == NULL) {
+               return;
+       }
+
        /*
         * Find the smallest element of number n
         */
@@ -267,10 +361,18 @@ void memcache_flush(struct memcache *cache, enum memcache_number n)
                return;
        }
 
+       /*
+        * First, find *any* element of number n
+        */
+
        while (true) {
                struct memcache_element *elem = memcache_node2elem(node);
                struct rb_node *next;
 
+               if ((int)elem->n == (int)n) {
+                       break;
+               }
+
                if ((int)elem->n < (int)n) {
                        next = node->rb_right;
                }
@@ -283,15 +385,36 @@ void memcache_flush(struct memcache *cache, enum memcache_number n)
                node = next;
        }
 
-       node = rb_next(node);
        if (node == NULL) {
                return;
        }
 
+       /*
+        * Then, find the leftmost element with number n
+        */
+
+       while (true) {
+               struct rb_node *prev = rb_prev(node);
+               struct memcache_element *elem;
+
+               if (prev == NULL) {
+                       break;
+               }
+               elem = memcache_node2elem(prev);
+               if ((int)elem->n != (int)n) {
+                       break;
+               }
+               node = prev;
+       }
+
        while (node != NULL) {
                struct memcache_element *e = memcache_node2elem(node);
                struct rb_node *next = rb_next(node);
 
+               if (e->n != n) {
+                       break;
+               }
+
                memcache_delete_element(cache, e);
                node = next;
        }