Add SETRANGE command implementation and tests

src/redis.c

@@ -80,6 +80,7 @@ struct redisCommand readonlyCommandTable[] = {
     {"exists",existsCommand,2,0,NULL,1,1,1},
     {"setbit",setbitCommand,4,REDIS_CMD_DENYOOM,NULL,1,1,1},
     {"getbit",getbitCommand,3,0,NULL,1,1,1},
+    {"setrange",setrangeCommand,4,REDIS_CMD_DENYOOM,NULL,1,1,1},
     {"incr",incrCommand,2,REDIS_CMD_DENYOOM,NULL,1,1,1},
     {"decr",decrCommand,2,REDIS_CMD_DENYOOM,NULL,1,1,1},
     {"mget",mgetCommand,-2,0,NULL,1,-1,1},

src/redis.h

@@ -889,6 +889,7 @@ void delCommand(redisClient *c);
 void existsCommand(redisClient *c);
 void setbitCommand(redisClient *c);
 void getbitCommand(redisClient *c);
+void setrangeCommand(redisClient *c);
 void incrCommand(redisClient *c);
 void decrCommand(redisClient *c);
 void incrbyCommand(redisClient *c);

src/t_string.c

@@ -5,6 +5,14 @@
  * String Commands
  *----------------------------------------------------------------------------*/
 
+static int checkStringLength(redisClient *c, long long size) {
+    if (size > 512*1024*1024) {
+        addReplyError(c,"string exceeds maximum allowed size (512MB)");
+        return REDIS_ERR;
+    }
+    return REDIS_OK;
+}
+
 void setGenericCommand(redisClient *c, int nx, robj *key, robj *val, robj *expire) {
     int retval;
     long seconds = 0; /* initialized to avoid an harmness warning */
@@ -172,6 +180,83 @@ void getbitCommand(redisClient *c) {
     addReply(c, on ? shared.cone : shared.czero);
 }
 
+void setrangeCommand(redisClient *c) {
+    robj *o;
+    long offset;
+    sds value = c->argv[3]->ptr;
+
+    if (getLongFromObjectOrReply(c,c->argv[2],&offset,NULL) != REDIS_OK)
+        return;
+
+    o = lookupKeyWrite(c->db,c->argv[1]);
+    if (o == NULL) {
+        /* Negative offset is always 0 for non-existing keys */
+        if (offset < 0) offset = 0;
+
+        /* Return 0 when setting nothing on a non-existing string */
+        if (sdslen(value) == 0) {
+            addReply(c,shared.czero);
+            return;
+        }
+
+        /* Return when the resulting string exceeds allowed size */
+        if (checkStringLength(c,offset+sdslen(value)) != REDIS_OK)
+            return;
+
+        o = createObject(REDIS_STRING,sdsempty());
+        dbAdd(c->db,c->argv[1],o);
+    } else {
+        int olen;
+
+        /* Key exists, check type */
+        if (checkType(c,o,REDIS_STRING))
+            return;
+
+        /* Find out existing value length */
+        if (o->encoding == REDIS_ENCODING_INT) {
+            char llbuf[32];
+            olen = ll2string(llbuf,sizeof(llbuf),(long)o->ptr);
+        } else {
+            olen = sdslen(o->ptr);
+        }
+
+        /* Return existing string length when setting nothing */
+        if (sdslen(value) == 0) {
+            addReplyLongLong(c,olen);
+            return;
+        }
+
+        /* Convert negative indexes. Note that for SETRANGE, the meaning of a
+         * negative index is a little different than for other commands.
+         * Here, an offset of -1 points to the trailing NULL byte of the
+         * string instead of the last character. */
+        if (offset < 0) {
+            offset = olen+1+offset;
+            if (offset < 0) offset = 0;
+        }
+
+        /* Return when the resulting string exceeds allowed size */
+        if (checkStringLength(c,offset+sdslen(value)) != REDIS_OK)
+            return;
+
+        /* Create a copy when the object is shared or encoded. */
+        if (o->refcount != 1 || o->encoding != REDIS_ENCODING_RAW) {
+            robj *decoded = getDecodedObject(o);
+            o = createStringObject(decoded->ptr, sdslen(decoded->ptr));
+            decrRefCount(decoded);
+            dbReplace(c->db,c->argv[1],o);
+        }
+    }
+
+    if (sdslen(value) > 0) {
+        o->ptr = sdsgrowzero(o->ptr,offset+sdslen(value));
+        memcpy((char*)o->ptr+offset,value,sdslen(value));
+        touchWatchedKey(c->db,c->argv[1]);
+        server.dirty++;
+    }
+    addReplyLongLong(c,sdslen(o->ptr));
+}
+
 void mgetCommand(redisClient *c) {
     int j;
 

tests/unit/basic.tcl

@@ -458,4 +458,108 @@ start_server {tags {"basic"}} {
         assert_equal 0 [r getbit mykey 100]
         assert_equal 0 [r getbit mykey 10000]
     }
+
+    test "SETRANGE against non-existing key" {
+        r del mykey
+        assert_equal 3 [r setrange mykey 0 foo]
+        assert_equal "foo" [r get mykey]
+
+        r del mykey
+        assert_equal 0 [r setrange mykey 0 ""]
+        assert_equal 0 [r exists mykey]
+
+        r del mykey
+        assert_equal 4 [r setrange mykey 1 foo]
+        assert_equal "\000foo" [r get mykey]
+
+        r del mykey
+        assert_equal 3 [r setrange mykey -1 foo]
+        assert_equal "foo" [r get mykey]
+
+        r del mykey
+        assert_equal 3 [r setrange mykey -100 foo]
+        assert_equal "foo" [r get mykey]
+    }
+
+    test "SETRANGE against string-encoded key" {
+        r set mykey "foo"
+        assert_equal 3 [r setrange mykey 0 b]
+        assert_equal "boo" [r get mykey]
+
+        r set mykey "foo"
+        assert_equal 3 [r setrange mykey 0 ""]
+        assert_equal "foo" [r get mykey]
+
+        r set mykey "foo"
+        assert_equal 3 [r setrange mykey 1 b]
+        assert_equal "fbo" [r get mykey]
+
+        r set mykey "foo"
+        assert_equal 6 [r setrange mykey -1 bar]
+        assert_equal "foobar" [r get mykey]
+
+        r set mykey "foo"
+        assert_equal 5 [r setrange mykey -2 bar]
+        assert_equal "fobar" [r get mykey]
+
+        r set mykey "foo"
+        assert_equal 3 [r setrange mykey -20 bar]
+        assert_equal "bar" [r get mykey]
+
+        r set mykey "foo"
+        assert_equal 7 [r setrange mykey 4 bar]
+        assert_equal "foo\000bar" [r get mykey]
+    }
+
+    test "SETRANGE against integer-encoded key" {
+        r set mykey 1234
+        assert_encoding int mykey
+        assert_equal 4 [r setrange mykey 0 2]
+        assert_encoding raw mykey
+        assert_equal 2234 [r get mykey]
+
+        # Shouldn't change encoding when nothing is set
+        r set mykey 1234
+        assert_encoding int mykey
+        assert_equal 4 [r setrange mykey 0 ""]
+        assert_encoding int mykey
+        assert_equal 1234 [r get mykey]
+
+        r set mykey 1234
+        assert_encoding int mykey
+        assert_equal 4 [r setrange mykey 1 3]
+        assert_encoding raw mykey
+        assert_equal 1334 [r get mykey]
+
+        r set mykey 1234
+        assert_encoding int mykey
+        assert_equal 5 [r setrange mykey -1 5]
+        assert_encoding raw mykey
+        assert_equal 12345 [r get mykey]
+
+        r set mykey 1234
+        assert_encoding int mykey
+        assert_equal 4 [r setrange mykey -2 5]
+        assert_encoding raw mykey
+        assert_equal 1235 [r get mykey]
+
+        r set mykey 1234
+        assert_encoding int mykey
+        assert_equal 6 [r setrange mykey 5 2]
+        assert_encoding raw mykey
+        assert_equal "1234\0002" [r get mykey]
+    }
+
+    test "SETRANGE against key with wrong type" {
+        r del mykey
+        r lpush mykey "foo"
+        assert_error "*wrong kind*" {r setrange mykey 0 bar}
+    }
+
+    test "SETRANGE with out of range offset" {
+        r del mykey
+        assert_error "*maximum allowed size*" {r setrange mykey [expr 512*1024*1024-4] world}
+        r set mykey "hello"
+        assert_error "*maximum allowed size*" {r setrange mykey [expr 512*1024*1024-4] world}
+    }
 }