rmutil: provide function to extract module-specific type

rmutil/util.c

@@ -231,3 +231,18 @@ RedisModuleCallReply *RedisModule_CallReplyArrayElementByPath(RedisModuleCallRep
 
   return ele;
 }
+
+int RedisModule_TryGetValue(RedisModuleKey *key, const RedisModuleType *type, void **out) {
+  if (key == NULL) {
+    return RMUTIL_VALUE_MISSING;
+  }
+  int keytype = RedisModule_KeyType(key);
+  if (keytype == REDISMODULE_KEYTYPE_EMPTY) {
+    return RMUTIL_VALUE_EMPTY;
+  } else if (keytype == REDISMODULE_KEYTYPE_MODULE && RedisModule_ModuleTypeGetType(key) == type) {
+    *out = RedisModule_ModuleTypeGetValue(key);
+    return RMUTIL_VALUE_OK;
+  } else {
+    return RMUTIL_VALUE_MISMATCH;
+  }
+}

rmutil/util.h

@@ -111,4 +111,23 @@ int RMUtilInfo_GetDouble(RMUtilInfo *info, const char *key, double *d);
 RedisModuleCallReply *RedisModule_CallReplyArrayElementByPath(RedisModuleCallReply *rep,
                                                               const char *path);
 
+/**
+ * Extract the module type from an opened key.
+ */
+typedef enum {
+  RMUTIL_VALUE_OK = 0,
+  RMUTIL_VALUE_MISSING,
+  RMUTIL_VALUE_EMPTY,
+  RMUTIL_VALUE_MISMATCH
+} RMUtil_TryGetValueStatus;
+
+/**
+ * Tries to extract the module-specific type from the value.
+ * @param key an opened key (may be null)
+ * @param type the pointer to the type to match to
+ * @param[out] out if the value is present, will be set to it.
+ * @return a value in the @ref RMUtil_TryGetValueStatus enum.
+ */
+int RedisModule_TryGetValue(RedisModuleKey *key, const RedisModuleType *type, void **out);
+
 #endif