set with ifeq support

Signed-off-by: Sarthak Aggarwal <[email protected]>

Author: sarthakaggarwal97

src/t_string.c

@@ -76,6 +76,7 @@ static int checkStringLength(client *c, long long size, long long append) {
 #define OBJ_EXAT (1 << 6)    /* Set if timestamp in second is given */
 #define OBJ_PXAT (1 << 7)    /* Set if timestamp in ms is given */
 #define OBJ_PERSIST (1 << 8) /* Set if we need to remove the ttl */
+#define OBJ_SET_IFEQ (1 << 9) /* Set if we need compare and set */
 
 /* Forward declaration */
 static int getExpireMillisecondsOrReply(client *c, robj *expire, int flags, int unit, long long *milliseconds);
@@ -87,7 +88,8 @@ void setGenericCommand(client *c,
                        robj *expire,
                        int unit,
                        robj *ok_reply,
-                       robj *abort_reply) {
+                       robj *abort_reply,
+                       robj *comparison) {
     long long milliseconds = 0; /* initialized to avoid any harmness warning */
     int found = 0;
     int setkey_flags = 0;
@@ -102,6 +104,15 @@ void setGenericCommand(client *c,
 
     found = (lookupKeyWrite(c->db, key) != NULL);
 
+    /* Handle the IFEQ conditional check */
+    if ((flags & OBJ_SET_IFEQ) && found) {
+        robj *current_value = lookupKeyRead(c->db, key);
+        if (current_value == NULL || compareStringObjects(current_value, comparison) != 0) {
+            addReply(c, abort_reply ? abort_reply : shared.null[c->resp]);
+            return;
+        }
+    }
+
     if ((flags & OBJ_SET_NX && found) || (flags & OBJ_SET_XX && !found)) {
         if (!(flags & OBJ_SET_GET)) {
             addReply(c, abort_reply ? abort_reply : shared.null[c->resp]);
@@ -208,7 +219,7 @@ static int getExpireMillisecondsOrReply(client *c, robj *expire, int flags, int
  * string arguments used in SET and GET command.
  *
  * Get specific commands - PERSIST/DEL
- * Set specific commands - XX/NX/GET
+ * Set specific commands - XX/NX/GET/IFEQ
  * Common commands - EX/EXAT/PX/PXAT/KEEPTTL
  *
  * Function takes pointers to client, flags, unit, pointer to pointer of expire obj if needed
@@ -219,7 +230,7 @@ static int getExpireMillisecondsOrReply(client *c, robj *expire, int flags, int
  * Input flags are updated upon parsing the arguments. Unit and expire are updated if there are any
  * EX/EXAT/PX/PXAT arguments. Unit is updated to millisecond if PX/PXAT is set.
  */
-int parseExtendedStringArgumentsOrReply(client *c, int *flags, int *unit, robj **expire, int command_type) {
+int parseExtendedStringArgumentsOrReply(client *c, int *flags, int *unit, robj **expire, robj **compare_val, int command_type) {
     int j = command_type == COMMAND_GET ? 2 : 3;
     for (; j < c->argc; j++) {
         char *opt = c->argv[j]->ptr;
@@ -295,7 +306,17 @@ int parseExtendedStringArgumentsOrReply(client *c, int *flags, int *unit, robj *
             *unit = UNIT_MILLISECONDS;
             *expire = next;
             j++;
-        } else {
+        } else if ((opt[0] == 'i' || opt[0] == 'I') &&
+            (opt[1] == 'f' || opt[1] == 'F') &&
+            (opt[2] == 'e' || opt[2] == 'E') &&
+            (opt[3] == 'q' || opt[3] == 'Q') && opt[4] == '\0' &&
+            next && (command_type == COMMAND_SET))
+        {
+            *flags |= OBJ_SET_IFEQ;
+            *compare_val = next;
+            j++;
+        }
+        else {
             addReplyErrorObject(c,shared.syntaxerr);
             return C_ERR;
         }
@@ -308,30 +329,31 @@ int parseExtendedStringArgumentsOrReply(client *c, int *flags, int *unit, robj *
  *     [EXAT <seconds-timestamp>][PXAT <milliseconds-timestamp>] */
 void setCommand(client *c) {
     robj *expire = NULL;
+    robj *comparison = NULL;
     int unit = UNIT_SECONDS;
     int flags = OBJ_NO_FLAGS;
 
-    if (parseExtendedStringArgumentsOrReply(c, &flags, &unit, &expire, COMMAND_SET) != C_OK) {
+    if (parseExtendedStringArgumentsOrReply(c, &flags, &unit, &expire, &comparison, COMMAND_SET) != C_OK) {
         return;
     }
 
     c->argv[2] = tryObjectEncoding(c->argv[2]);
-    setGenericCommand(c, flags, c->argv[1], c->argv[2], expire, unit, NULL, NULL);
+    setGenericCommand(c, flags, c->argv[1], c->argv[2], expire, unit, NULL, NULL, comparison);
 }
 
 void setnxCommand(client *c) {
     c->argv[2] = tryObjectEncoding(c->argv[2]);
-    setGenericCommand(c, OBJ_SET_NX, c->argv[1], c->argv[2], NULL, 0, shared.cone, shared.czero);
+    setGenericCommand(c, OBJ_SET_NX, c->argv[1], c->argv[2], NULL, 0, shared.cone, shared.czero, NULL);
 }
 
 void setexCommand(client *c) {
     c->argv[3] = tryObjectEncoding(c->argv[3]);
-    setGenericCommand(c, OBJ_EX, c->argv[1], c->argv[3], c->argv[2], UNIT_SECONDS, NULL, NULL);
+    setGenericCommand(c, OBJ_EX, c->argv[1], c->argv[3], c->argv[2], UNIT_SECONDS, NULL, NULL, NULL);
 }
 
 void psetexCommand(client *c) {
     c->argv[3] = tryObjectEncoding(c->argv[3]);
-    setGenericCommand(c, OBJ_PX, c->argv[1], c->argv[3], c->argv[2], UNIT_MILLISECONDS, NULL, NULL);
+    setGenericCommand(c, OBJ_PX, c->argv[1], c->argv[3], c->argv[2], UNIT_MILLISECONDS, NULL, NULL, NULL);
 }
 
 int getGenericCommand(client *c) {
@@ -374,10 +396,11 @@ void getCommand(client *c) {
  */
 void getexCommand(client *c) {
     robj *expire = NULL;
+    robj *comparison = NULL;
     int unit = UNIT_SECONDS;
     int flags = OBJ_NO_FLAGS;
 
-    if (parseExtendedStringArgumentsOrReply(c, &flags, &unit, &expire, COMMAND_GET) != C_OK) {
+    if (parseExtendedStringArgumentsOrReply(c, &flags, &unit, &expire, &comparison, COMMAND_GET) != C_OK) {
         return;
     }
 

tests/unit/type/string.tcl

@@ -582,6 +582,19 @@ if {[string match {*jemalloc*} [s mem_allocator]]} {
       set err1
     } {*WRONGTYPE*}
 
+    test "SET with IFEQ conditional" {
+        # Setting an initial value for the key
+        r set foo "initial_value"
+
+        # Trying to set the key only if the value is exactly "initial_value"
+        assert_equal OK [r set foo "new_value" ifeq "initial_value"]
+        assert_equal "new_value" [r get foo]
+
+        # Trying to set the key only if the value is NOT "initial_value"
+        assert_equal {} [r set foo "should_not_set" ifeq "wrong_value"]
+        assert_equal "new_value" [r get foo]
+    }
+
     test {Extended SET EX option} {
         r del foo
         r set foo bar ex 10