Expr: handle JSON arrays as expr tuples.

expr.c

@@ -699,6 +699,63 @@ int exprTokensEqual(exprtoken *a, exprtoken *b) {
     return exprTokenToNum(a) == exprTokenToNum(b);
 }
 
+/* Convert a json object to an expression token. There is only
+ * limited support for JSON arrays: they must be composed of
+ * just numbers and strings. Returns NULL if the JSON object
+ * cannot be converted. */
+exprtoken *exprJsonToToken(cJSON *js) {
+    if (cJSON_IsNumber(js)) {
+        exprtoken *obj = exprNewToken(EXPR_TOKEN_NUM);
+        obj->num = cJSON_GetNumberValue(js);
+        return obj;
+    } else if (cJSON_IsString(js)) {
+        exprtoken *obj = exprNewToken(EXPR_TOKEN_STR);
+        char *strval = cJSON_GetStringValue(js);
+        obj->str.heapstr = RedisModule_Strdup(strval);
+        obj->str.start = obj->str.heapstr;
+        obj->str.len = strlen(obj->str.heapstr);
+        return obj;
+    } else if (cJSON_IsArray(js)) {
+        // First, scan the array to ensure it only
+        // contains strings and numbers. Otherwise the
+        // expression will evaluate to false.
+        int array_size = cJSON_GetArraySize(js);
+
+        for (int j = 0; j < array_size; j++) {
+            cJSON *item = cJSON_GetArrayItem(js, j);
+            if (!cJSON_IsNumber(item) && !cJSON_IsString(item)) return NULL;
+        }
+
+        // Create a tuple token for the array.
+        exprtoken *obj = exprNewToken(EXPR_TOKEN_TUPLE);
+        obj->tuple.len = array_size;
+        obj->tuple.ele = NULL;
+        if (obj->tuple.len == 0) return obj; // No elements, already ok.
+
+        obj->tuple.ele =
+            RedisModule_Alloc(sizeof(exprtoken*) * obj->tuple.len);
+
+        // Convert each array element to a token.
+        for (size_t j = 0; j < obj->tuple.len; j++) {
+            cJSON *item = cJSON_GetArrayItem(js, j);
+            if (cJSON_IsNumber(item)) {
+                exprtoken *eleToken = exprNewToken(EXPR_TOKEN_NUM);
+                eleToken->num = cJSON_GetNumberValue(item);
+                obj->tuple.ele[j] = eleToken;
+            } else if (cJSON_IsString(item)) {
+                exprtoken *eleToken = exprNewToken(EXPR_TOKEN_STR);
+                char *strval = cJSON_GetStringValue(item);
+                eleToken->str.heapstr = RedisModule_Strdup(strval);
+                eleToken->str.start = eleToken->str.heapstr;
+                eleToken->str.len = strlen(eleToken->str.heapstr);
+                obj->tuple.ele[j] = eleToken;
+            }
+        }
+        return obj;
+    }
+    return NULL; // No conversion possible for this type.
+}
+
 /* Execute the compiled expression program. Returns 1 if the final stack value
  * evaluates to true, 0 otherwise. Also returns 0 if any selector callback
  * fails. */
@@ -728,28 +785,19 @@ int exprRun(exprstate *es, char *json, size_t json_len) {
                     /* Fill the token according to the JSON type stored
                      * at the attribute. */
                     if (attrib) {
-                        if (cJSON_IsNumber(attrib)) {
+                        exprtoken *obj = exprJsonToToken(attrib);
-                            exprtoken *obj = exprNewToken(EXPR_TOKEN_NUM);
+                        if (obj) {
-                            obj->num = cJSON_GetNumberValue(attrib);
                             exprStackPush(&es->values_stack, obj);
-                        } else if (cJSON_IsString(attrib)) {
+                            continue;
-                            exprtoken *obj = exprNewToken(EXPR_TOKEN_STR);
-                            char *strval = cJSON_GetStringValue(attrib);
-                            obj->str.heapstr = RedisModule_Strdup(strval);
-                            obj->str.start = obj->str.heapstr;
-                            obj->str.len = strlen(obj->str.heapstr);
-                            exprStackPush(&es->values_stack, obj);
-                        } else {
-                            /* XXX: fixme: turn JS arrays into tuples. */
-                            attrib = NULL; // Unsupported type.
                         }
                     }
-                    if (attrib) continue; // Selector found and pushed on stack.
                 }
             }
 
+            // Selector not found or JSON object not convertible to
+            // expression tokens. Evaluate the expression to false.
             if (parsed_json) cJSON_Delete(parsed_json);
-            return 0;  // Selector not found: expression evaluates to false.
+            return 0;
         }
 
         // Push non-operator values directly onto the stack.