initial skiplist implementation. Most memory checks removed and zmalloc() modified to fail with an error message and abort. Anyway Redis is not designed to recover from out of memory conditions.

zmalloc.c

@@ -28,16 +28,24 @@
  * POSSIBILITY OF SUCH DAMAGE.
  */
 
+#include <stdio.h>
 #include <stdlib.h>
 #include <string.h>
 #include "config.h"
 
 static size_t used_memory = 0;
 
+static void zmalloc_oom(size_t size) {
+    fprintf(stderr, "zmalloc: Out of memory trying to allocate %lu bytes\n",
+        size);
+    fflush(stderr);
+    abort();
+}
+
 void *zmalloc(size_t size) {
     void *ptr = malloc(size+sizeof(size_t));
 
-    if (!ptr) return NULL;
+    if (!ptr) zmalloc_oom(size);
 #ifdef HAVE_MALLOC_SIZE
     used_memory += redis_malloc_size(ptr);
     return ptr;
@@ -59,7 +67,7 @@ void *zrealloc(void *ptr, size_t size) {
 #ifdef HAVE_MALLOC_SIZE
     oldsize = redis_malloc_size(ptr);
     newptr = realloc(ptr,size);
-    if (!newptr) return NULL;
+    if (!newptr) zmalloc_oom(size);
 
     used_memory -= oldsize;
     used_memory += redis_malloc_size(newptr);
@@ -68,7 +76,7 @@ void *zrealloc(void *ptr, size_t size) {
     realptr = (char*)ptr-sizeof(size_t);
     oldsize = *((size_t*)realptr);
     newptr = realloc(realptr,size+sizeof(size_t));
-    if (!newptr) return NULL;
+    if (!newptr) zmalloc_oom(size);
 
     *((size_t*)newptr) = size;
     used_memory -= oldsize;