added HSETNX

redis.c

@@ -705,6 +705,7 @@ static void substrCommand(redisClient *c);
 static void zrankCommand(redisClient *c);
 static void zrevrankCommand(redisClient *c);
 static void hsetCommand(redisClient *c);
+static void hsetnxCommand(redisClient *c);
 static void hgetCommand(redisClient *c);
 static void hmsetCommand(redisClient *c);
 static void hmgetCommand(redisClient *c);
@@ -783,6 +784,7 @@ static struct redisCommand cmdTable[] = {
     {"zrank",zrankCommand,3,REDIS_CMD_BULK,NULL,1,1,1},
     {"zrevrank",zrevrankCommand,3,REDIS_CMD_BULK,NULL,1,1,1},
     {"hset",hsetCommand,4,REDIS_CMD_BULK|REDIS_CMD_DENYOOM,NULL,1,1,1},
+    {"hsetnx",hsetnxCommand,4,REDIS_CMD_BULK|REDIS_CMD_DENYOOM,NULL,1,1,1},
     {"hget",hgetCommand,3,REDIS_CMD_BULK,NULL,1,1,1},
     {"hmset",hmsetCommand,-4,REDIS_CMD_BULK|REDIS_CMD_DENYOOM,NULL,1,1,1},
     {"hmget",hmgetCommand,-3,REDIS_CMD_BULK,NULL,1,1,1},
@@ -6247,6 +6249,20 @@ static void hsetCommand(redisClient *c) {
     server.dirty++;
 }
 
+static void hsetnxCommand(redisClient *c) {
+    robj *o;
+    if ((o = hashLookupWriteOrCreate(c,c->argv[1])) == NULL) return;
+    hashTryConversion(o,c->argv,2,3);
+
+    if (hashExists(o, c->argv[2])) {
+        addReply(c, shared.czero);
+    } else {
+        hashReplace(o,c->argv[2],c->argv[3]);
+        addReply(c, shared.cone);
+        server.dirty++;
+    }
+}
+
 static void hmsetCommand(redisClient *c) {
     int i;
     robj *o;

redis.tcl

@@ -46,7 +46,7 @@ foreach redis_bulk_cmd {
 
 # Flag commands requiring last argument as a bulk write operation
 foreach redis_multibulk_cmd {
-    mset msetnx hset hmset hmget
+    mset msetnx hset hsetnx hmset hmget
 } {
     set ::redis::multibulkarg($redis_multibulk_cmd) {}
 }

test-redis.tcl

@@ -1652,6 +1652,30 @@ proc main {} {
         set _ $rv
     } {0 newval1 1 0 newval2 1 1 1}
 
+    test {HSETNX target key missing - small hash} {
+        $r hsetnx smallhash __123123123__ foo
+        $r hget smallhash __123123123__
+    } {foo}
+
+    test {HSETNX target key exists - small hash} {
+        $r hsetnx smallhash __123123123__ bar
+        set result [$r hget smallhash __123123123__]
+        $r hdel smallhash __123123123__
+        set _ $result
+    } {foo}
+
+    test {HSETNX target key missing - big hash} {
+        $r hsetnx bighash __123123123__ foo
+        $r hget bighash __123123123__
+    } {foo}
+
+    test {HSETNX target key exists - big hash} {
+        $r hsetnx bighash __123123123__ bar
+        set result [$r hget bighash __123123123__]
+        $r hdel bighash __123123123__
+        set _ $result
+    } {foo}
+
     test {HMSET wrong number of args} {
         catch {$r hmset smallhash key1 val1 key2} err
         format $err