Merge pull request #3511 from dvirsky/create_string_printf

added RM_CreateStringPrintf

src/module.c

@@ -681,13 +681,33 @@ void autoMemoryCollect(RedisModuleCtx *ctx) {
  *
  * The string is created by copying the `len` bytes starting
  * at `ptr`. No reference is retained to the passed buffer. */
-RedisModuleString *RM_CreateString(RedisModuleCtx *ctx, const char *ptr, size_t len)
-{
+RedisModuleString *RM_CreateString(RedisModuleCtx *ctx, const char *ptr, size_t len) {
     RedisModuleString *o = createStringObject(ptr,len);
     autoMemoryAdd(ctx,REDISMODULE_AM_STRING,o);
     return o;
 }
 
+
+/* Create a new module string object from a printf format and arguments. 
+ * The returned string must be freed with RedisModule_FreeString(), unless automatic 
+ * memory is enabled.
+ *
+ * The string is created using the sds formatter function sdscatvprintf() */ 
+RedisModuleString *RM_CreateStringPrintf(RedisModuleCtx *ctx, const char *fmt, ...) {
+    sds s = sdsempty();
+
+    va_list ap;
+    va_start(ap, fmt);
+    s = sdscatvprintf(s, fmt, ap);
+    va_end(ap);
+
+    RedisModuleString *o = createObject(OBJ_STRING, s);
+    autoMemoryAdd(ctx,REDISMODULE_AM_STRING,o);
+
+    return o;
+}
+
+
 /* Like RedisModule_CreatString(), but creates a string starting from a long long
  * integer instead of taking a buffer and its length.
  *
@@ -3194,6 +3214,7 @@ void moduleRegisterCoreAPI(void) {
     REGISTER_API(CreateString);
     REGISTER_API(CreateStringFromLongLong);
     REGISTER_API(CreateStringFromString);
+    REGISTER_API(CreateStringPrintf);
     REGISTER_API(FreeString);
     REGISTER_API(StringPtrLen);
     REGISTER_API(AutoMemory);

src/modules/testmodule.c

@@ -93,6 +93,25 @@ int TestStringAppendAM(RedisModuleCtx *ctx, RedisModuleString **argv, int argc)
     return REDISMODULE_OK;
 }
 
+/* TEST.STRING.PRINTF -- Test string formatting. */
+int TestStringPrintf(RedisModuleCtx *ctx, RedisModuleString **argv, int argc) {
+    RedisModule_AutoMemory(ctx);
+    if (argc < 3) {
+        return RedisModule_WrongArity(ctx);
+    }
+    RedisModuleString *s = RedisModule_CreateStringPrintf(ctx, 
+        "Got %d args. argv[1]: %s, argv[2]: %s", 
+        argc, 
+        RedisModule_StringPtrLen(argv[1], NULL),
+        RedisModule_StringPtrLen(argv[2], NULL)
+    );
+
+    RedisModule_ReplyWithString(ctx,s);
+
+    return REDISMODULE_OK;
+}
+
+
 /* ----------------------------- Test framework ----------------------------- */
 
 /* Return 1 if the reply matches the specified string, otherwise log errors
@@ -163,6 +182,9 @@ int TestIt(RedisModuleCtx *ctx, RedisModuleString **argv, int argc) {
     T("test.string.append.am","");
     if (!TestAssertStringReply(ctx,reply,"foobar",6)) goto fail;
 
+    T("test.string.printf", "cc", "foo", "bar");
+    if (!TestAssertStringReply(ctx,reply,"Got 3 args. argv[1]: foo, argv[2]: bar",38)) goto fail;
+
     RedisModule_ReplyWithSimpleString(ctx,"ALL TESTS PASSED");
     return REDISMODULE_OK;
 
@@ -188,6 +210,10 @@ int RedisModule_OnLoad(RedisModuleCtx *ctx, RedisModuleString **argv, int argc)
         TestStringAppendAM,"write deny-oom",1,1,1) == REDISMODULE_ERR)
         return REDISMODULE_ERR;
 
+    if (RedisModule_CreateCommand(ctx,"test.string.printf",
+        TestStringPrintf,"write deny-oom",1,1,1) == REDISMODULE_ERR)
+        return REDISMODULE_ERR;
+
     if (RedisModule_CreateCommand(ctx,"test.it",
         TestIt,"readonly",1,1,1) == REDISMODULE_ERR)
         return REDISMODULE_ERR;

src/object.c

@@ -75,7 +75,7 @@ robj *makeObjectShared(robj *o) {
 /* Create a string object with encoding OBJ_ENCODING_RAW, that is a plain
  * string object where o->ptr points to a proper sds string. */
 robj *createRawStringObject(const char *ptr, size_t len) {
-    return createObject(OBJ_STRING,sdsnewlen(ptr,len));
+    return createObject(OBJ_STRING, sdsnewlen(ptr,len));
 }
 
 /* Create a string object with encoding OBJ_ENCODING_EMBSTR, that is

src/redismodule.h

@@ -125,6 +125,7 @@ RedisModuleCallReply *REDISMODULE_API_FUNC(RedisModule_CallReplyArrayElement)(Re
 RedisModuleString *REDISMODULE_API_FUNC(RedisModule_CreateString)(RedisModuleCtx *ctx, const char *ptr, size_t len);
 RedisModuleString *REDISMODULE_API_FUNC(RedisModule_CreateStringFromLongLong)(RedisModuleCtx *ctx, long long ll);
 RedisModuleString *REDISMODULE_API_FUNC(RedisModule_CreateStringFromString)(RedisModuleCtx *ctx, const RedisModuleString *str);
+RedisModuleString *REDISMODULE_API_FUNC(RedisModule_CreateStringPrintf)(RedisModuleCtx *ctx, const char *fmt, ...);
 void REDISMODULE_API_FUNC(RedisModule_FreeString)(RedisModuleCtx *ctx, RedisModuleString *str);
 const char *REDISMODULE_API_FUNC(RedisModule_StringPtrLen)(const RedisModuleString *str, size_t *len);
 int REDISMODULE_API_FUNC(RedisModule_ReplyWithError)(RedisModuleCtx *ctx, const char *err);
@@ -234,6 +235,7 @@ static int RedisModule_Init(RedisModuleCtx *ctx, const char *name, int ver, int
     REDISMODULE_GET_API(CreateString);
     REDISMODULE_GET_API(CreateStringFromLongLong);
     REDISMODULE_GET_API(CreateStringFromString);
+    REDISMODULE_GET_API(CreateStringPrintf);
     REDISMODULE_GET_API(FreeString);
     REDISMODULE_GET_API(StringPtrLen);
     REDISMODULE_GET_API(AutoMemory);