Add unique constraint to enumeration parameters

Enum parameters can now be declared unique. This prevents multiple values
for enumerations which only accept one value.

include/maxscale/modinfo.h

@@ -98,7 +98,8 @@ enum mxs_module_param_options
     MXS_MODULE_OPT_PATH_X_OK   = (1 << 1), /**< PATH: Execute permission to path required */
     MXS_MODULE_OPT_PATH_R_OK   = (1 << 2), /**< PATH: Read permission to path required */
     MXS_MODULE_OPT_PATH_W_OK   = (1 << 3), /**< PATH: Write permission to path required */
-    MXS_MODULE_OPT_PATH_F_OK   = (1 << 4)  /**< PATH: Path must exist */
+    MXS_MODULE_OPT_PATH_F_OK   = (1 << 4), /**< PATH: Path must exist */
+    MXS_MODULE_OPT_ENUM_UNIQUE = (1 << 5)  /**< ENUM: Only one value can be defined */
 };
 
 /** String to enum value mappings */

server/core/config.c

@@ -3262,7 +3262,16 @@ bool config_param_is_valid(const MXS_MODULE_PARAM *params, const char *key,
                                     break;
                                 }
                             }
+
                             tok = strtok_r(NULL, delim, &endptr);
+
+                            if ((params[i].options & MXS_MODULE_OPT_ENUM_UNIQUE) && (tok || !valid))
+                            {
+                                /** Either the only defined enum value is not valid
+                                 * or multiple values were defined */
+                                valid = false;
+                                break;
+                            }
                         }
                     }
                     break;

server/core/test/testconfig.c

@@ -39,6 +39,7 @@ int test_validity()
         {"p5", MXS_MODULE_PARAM_ENUM, "a", MXS_MODULE_OPT_NONE, enum_values},
         {"p6", MXS_MODULE_PARAM_PATH, "/tmp", MXS_MODULE_OPT_PATH_F_OK},
         {"p7", MXS_MODULE_PARAM_SERVICE, "my-service"},
+        {"p8", MXS_MODULE_PARAM_ENUM, "a", MXS_MODULE_OPT_ENUM_UNIQUE, enum_values},
         {MXS_END_MODULE_PARAMS}
     };
 
@@ -76,7 +77,13 @@ int test_validity()
     TEST(config_param_is_valid(params, "p5", "a", &ctx));
     TEST(config_param_is_valid(params, "p5", "b", &ctx));
     TEST(config_param_is_valid(params, "p5", "c", &ctx));
+    TEST(config_param_is_valid(params, "p5", "a,b", &ctx));
+    TEST(config_param_is_valid(params, "p5", "b,a", &ctx));
+    TEST(config_param_is_valid(params, "p5", "a, b, c", &ctx));
+    TEST(config_param_is_valid(params, "p5", "c,a,b", &ctx));
     TEST(!config_param_is_valid(params, "p5", "d", &ctx));
+    TEST(!config_param_is_valid(params, "p5", "a,d", &ctx));
+    TEST(!config_param_is_valid(params, "p5", "a,b,c,d", &ctx));
 
     /** Path parameter */
     TEST(config_param_is_valid(params, "p6", "/tmp", &ctx));
@@ -90,6 +97,18 @@ int test_validity()
     TEST(!config_param_is_valid(params, "p7", "test-service", NULL));
     TEST(!config_param_is_valid(params, "p7", "no-such-service", &ctx));
 
+    /** Unique enum parameter */
+    TEST(config_param_is_valid(params, "p8", "a", &ctx));
+    TEST(config_param_is_valid(params, "p8", "b", &ctx));
+    TEST(config_param_is_valid(params, "p8", "c", &ctx));
+    TEST(!config_param_is_valid(params, "p8", "a,b", &ctx));
+    TEST(!config_param_is_valid(params, "p8", "b,a", &ctx));
+    TEST(!config_param_is_valid(params, "p8", "a, b, c", &ctx));
+    TEST(!config_param_is_valid(params, "p8", "c,a,b", &ctx));
+    TEST(!config_param_is_valid(params, "p8", "d", &ctx));
+    TEST(!config_param_is_valid(params, "p8", "a,d", &ctx));
+    TEST(!config_param_is_valid(params, "p8", "a,b,c,d", &ctx));
+
     return 0;
 }