Adding support for sharing memory between the module and the engine

src/aof.c

@@ -1955,8 +1955,9 @@ static int rioWriteHashIteratorCursor(rio *r, hashTypeIterator *hi, int what) {
         else
             return rioWriteBulkLongLong(r, vll);
     } else if (hi->encoding == OBJ_ENCODING_HASHTABLE) {
-        sds value = hashTypeCurrentFromHashTable(hi, what);
-        return rioWriteBulkString(r, value, sdslen(value));
+        size_t len;
+        char *value = hashTypeCurrentFromHashTable(hi, what, &len);
+        return rioWriteBulkString(r, value, len);
     }
 
     serverPanic("Unknown hash encoding");
@@ -1974,7 +1975,8 @@ int rewriteHashObject(rio *r, robj *key, robj *o) {
         while (hashTypeNext(&hi) != C_ERR) {
             long long expiry = entryGetExpiry(hi.next);
             sds field = entryGetField(hi.next);
-            sds value = entryGetValue(hi.next);
+            size_t value_len;
+            char *value = entryGetValue(hi.next, &value_len);
             if (rioWriteBulkCount(r, '*', 8) == 0) return 0;
             if (rioWriteBulkString(r, "HSETEX", 6) == 0) return 0;
             if (rioWriteBulkObject(r, key) == 0) return 0;
@@ -1983,7 +1985,7 @@ int rewriteHashObject(rio *r, robj *key, robj *o) {
             if (rioWriteBulkString(r, "FIELDS", 6) == 0) return 0;
             if (rioWriteBulkLongLong(r, 1) == 0) return 0;
             if (rioWriteBulkString(r, field, sdslen(field)) == 0) return 0;
-            if (rioWriteBulkString(r, value, sdslen(value)) == 0) return 0;
+            if (rioWriteBulkString(r, value, value_len) == 0) return 0;
             volatile_items++;
         }
         hashTypeResetIterator(&hi);

src/db.c

@@ -1001,6 +1001,12 @@ int objectTypeCompare(robj *o, long long target) {
         return 1;
 }
 
+static void addScanDataItem(vector *result, const char *buf, size_t len) {
+    stringRef *item = vectorPush(result);
+    item->buf = buf;
+    item->len = len;
+}
+
 /* Hashtable scan callback used by scanCallback when scanning the keyspace. */
 void keysScanCallback(void *privdata, void *entry, int didx) {
     scanData *data = (scanData *)privdata;
@@ -1031,15 +1037,14 @@ void keysScanCallback(void *privdata, void *entry, int didx) {
     }
 
     /* Keep this key. */
-    sds *item = vectorPush(data->result);
-    *item = key;
+    addScanDataItem(data->result, (const char *)key, sdslen(key));
 }
 
 /* This callback is used by scanGenericCommand in order to collect elements
  * returned by the dictionary iterator into a list. */
 void hashtableScanCallback(void *privdata, void *entry) {
     scanData *data = (scanData *)privdata;
-    sds val = NULL;
+    stringRef val = {NULL, 0};
     sds key = NULL;
 
     robj *o = data->o;
@@ -1059,7 +1064,7 @@ void hashtableScanCallback(void *privdata, void *entry) {
     } else if (o->type == OBJ_HASH) {
         key = entryGetField(entry);
         if (!data->only_keys) {
-            val = entryGetValue(entry);
+            val.buf = entryGetValue(entry, &val.len);
         }
     } else {
         serverPanic("Type not handled in hashtable SCAN callback.");
@@ -1081,15 +1086,15 @@ void hashtableScanCallback(void *privdata, void *entry) {
         if (!data->only_keys) {
             char buf[MAX_LONG_DOUBLE_CHARS];
             int len = ld2string(buf, sizeof(buf), node->score, LD_STR_AUTO);
-            val = sdsnewlen(buf, len);
+            sds tmp = sdsnewlen(buf, len);
+            val.buf = (const char *)tmp;
+            val.len = sdslen(tmp);
         }
     }
 
-    sds *item = vectorPush(data->result);
-    *item = key;
-    if (val) {
-        item = vectorPush(data->result);
-        *item = val;
+    addScanDataItem(data->result, (const char *)key, sdslen(key));
+    if (val.buf) {
+        addScanDataItem(data->result, val.buf, val.len);
     }
 }
 
@@ -1244,7 +1249,7 @@ void scanGenericCommand(client *c, robj *o, unsigned long long cursor) {
         /* scanning ZSET allocates temporary strings even though it's a dict */
         free_callback = sdsfree;
     }
-    vectorInit(&result, SCAN_VECTOR_INITIAL_ALLOC, sizeof(sds));
+    vectorInit(&result, SCAN_VECTOR_INITIAL_ALLOC, sizeof(stringRef));
 
     /* For main hash table scan or scannable data structure. */
     if (!o || ht) {
@@ -1305,8 +1310,8 @@ void scanGenericCommand(client *c, robj *o, unsigned long long cursor) {
             if (use_pattern && !stringmatchlen(pat, sdslen(pat), key, len, 0)) {
                 continue;
             }
-            sds *item = vectorPush(&result);
-            *item = sdsnewlen(key, len);
+            sds item = sdsnewlen(key, len);
+            addScanDataItem(&result, (const char *)item, sdslen(item));
         }
         setTypeReleaseIterator(si);
         cursor = 0;
@@ -1326,13 +1331,13 @@ void scanGenericCommand(client *c, robj *o, unsigned long long cursor) {
                 continue;
             }
             /* add key object */
-            sds *item = vectorPush(&result);
-            *item = sdsnewlen(str, len);
+            sds item = sdsnewlen(str, len);
+            addScanDataItem(&result, (const char *)item, sdslen(item));
             /* add value object */
             if (!only_keys) {
                 str = lpGet(p, &len, intbuf);
-                item = vectorPush(&result);
-                *item = sdsnewlen(str, len);
+                item = sdsnewlen(str, len);
+                addScanDataItem(&result, (const char *)item, sdslen(item));
             }
             p = lpNext(o->ptr, p);
         }
@@ -1347,10 +1352,10 @@ void scanGenericCommand(client *c, robj *o, unsigned long long cursor) {
 
     addReplyArrayLen(c, vectorLen(&result));
     for (uint32_t i = 0; i < vectorLen(&result); i++) {
-        sds *key = vectorGet(&result, i);
-        addReplyBulkCBuffer(c, *key, sdslen(*key));
+        stringRef *key = vectorGet(&result, i);
+        addReplyBulkCBuffer(c, key->buf, key->len);
         if (free_callback) {
-            free_callback(*key);
+            free_callback((sds)(key->buf));
         }
     }