client: extract capability-to-name function from CapabilityString()

This makes this more flexible and improves the testability of this.

Author: dveeden

client/conn.go

@@ -581,72 +581,9 @@ func (c *Conn) CapabilityString() string {
 		field := uint32(1 << bits.TrailingZeros32(capability))
 		capability ^= field
 
-		switch field {
-		case mysql.CLIENT_LONG_PASSWORD:
-			caps = append(caps, "CLIENT_LONG_PASSWORD")
-		case mysql.CLIENT_FOUND_ROWS:
-			caps = append(caps, "CLIENT_FOUND_ROWS")
-		case mysql.CLIENT_LONG_FLAG:
-			caps = append(caps, "CLIENT_LONG_FLAG")
-		case mysql.CLIENT_CONNECT_WITH_DB:
-			caps = append(caps, "CLIENT_CONNECT_WITH_DB")
-		case mysql.CLIENT_NO_SCHEMA:
-			caps = append(caps, "CLIENT_NO_SCHEMA")
-		case mysql.CLIENT_COMPRESS:
-			caps = append(caps, "CLIENT_COMPRESS")
-		case mysql.CLIENT_ODBC:
-			caps = append(caps, "CLIENT_ODBC")
-		case mysql.CLIENT_LOCAL_FILES:
-			caps = append(caps, "CLIENT_LOCAL_FILES")
-		case mysql.CLIENT_IGNORE_SPACE:
-			caps = append(caps, "CLIENT_IGNORE_SPACE")
-		case mysql.CLIENT_PROTOCOL_41:
-			caps = append(caps, "CLIENT_PROTOCOL_41")
-		case mysql.CLIENT_INTERACTIVE:
-			caps = append(caps, "CLIENT_INTERACTIVE")
-		case mysql.CLIENT_SSL:
-			caps = append(caps, "CLIENT_SSL")
-		case mysql.CLIENT_IGNORE_SIGPIPE:
-			caps = append(caps, "CLIENT_IGNORE_SIGPIPE")
-		case mysql.CLIENT_TRANSACTIONS:
-			caps = append(caps, "CLIENT_TRANSACTIONS")
-		case mysql.CLIENT_RESERVED:
-			caps = append(caps, "CLIENT_RESERVED")
-		case mysql.CLIENT_SECURE_CONNECTION:
-			caps = append(caps, "CLIENT_SECURE_CONNECTION")
-		case mysql.CLIENT_MULTI_STATEMENTS:
-			caps = append(caps, "CLIENT_MULTI_STATEMENTS")
-		case mysql.CLIENT_MULTI_RESULTS:
-			caps = append(caps, "CLIENT_MULTI_RESULTS")
-		case mysql.CLIENT_PS_MULTI_RESULTS:
-			caps = append(caps, "CLIENT_PS_MULTI_RESULTS")
-		case mysql.CLIENT_PLUGIN_AUTH:
-			caps = append(caps, "CLIENT_PLUGIN_AUTH")
-		case mysql.CLIENT_CONNECT_ATTRS:
-			caps = append(caps, "CLIENT_CONNECT_ATTRS")
-		case mysql.CLIENT_PLUGIN_AUTH_LENENC_CLIENT_DATA:
-			caps = append(caps, "CLIENT_PLUGIN_AUTH_LENENC_CLIENT_DATA")
-		case mysql.CLIENT_CAN_HANDLE_EXPIRED_PASSWORDS:
-			caps = append(caps, "CLIENT_CAN_HANDLE_EXPIRED_PASSWORDS")
-		case mysql.CLIENT_SESSION_TRACK:
-			caps = append(caps, "CLIENT_SESSION_TRACK")
-		case mysql.CLIENT_DEPRECATE_EOF:
-			caps = append(caps, "CLIENT_DEPRECATE_EOF")
-		case mysql.CLIENT_OPTIONAL_RESULTSET_METADATA:
-			caps = append(caps, "CLIENT_OPTIONAL_RESULTSET_METADATA")
-		case mysql.CLIENT_ZSTD_COMPRESSION_ALGORITHM:
-			caps = append(caps, "CLIENT_ZSTD_COMPRESSION_ALGORITHM")
-		case mysql.CLIENT_QUERY_ATTRIBUTES:
-			caps = append(caps, "CLIENT_QUERY_ATTRIBUTES")
-		case mysql.MULTI_FACTOR_AUTHENTICATION:
-			caps = append(caps, "MULTI_FACTOR_AUTHENTICATION")
-		case mysql.CLIENT_CAPABILITY_EXTENSION:
-			caps = append(caps, "CLIENT_CAPABILITY_EXTENSION")
-		case mysql.CLIENT_SSL_VERIFY_SERVER_CERT:
-			caps = append(caps, "CLIENT_SSL_VERIFY_SERVER_CERT")
-		case mysql.CLIENT_REMEMBER_OPTIONS:
-			caps = append(caps, "CLIENT_REMEMBER_OPTIONS")
-		default:
+		if capname, ok := mysql.CapNames[field]; ok {
+			caps = append(caps, capname)
+		} else {
 			caps = append(caps, fmt.Sprintf("(%d)", field))
 		}
 	}

client/conn_test.go

@@ -237,3 +237,10 @@ func (s *connTestSuite) TestUseDB() {
 	err = s.c.UseDB("test")
 	require.NoError(s.T(), err)
 }
+
+func TestCapabilityString(t *testing.T) {
+	conn := Conn{
+		capability: mysql.CLIENT_PROTOCOL_41 | mysql.CLIENT_DEPRECATE_EOF,
+	}
+	require.Equal(t, "CLIENT_PROTOCOL_41|CLIENT_DEPRECATE_EOF", conn.CapabilityString())
+}

mysql/const.go

@@ -122,6 +122,41 @@ const (
 	CLIENT_REMEMBER_OPTIONS
 )
 
+var CapNames = map[uint32]string{
+	CLIENT_LONG_PASSWORD:                  "CLIENT_LONG_PASSWORD",
+	CLIENT_FOUND_ROWS:                     "CLIENT_FOUND_ROWS",
+	CLIENT_LONG_FLAG:                      "CLIENT_LONG_FLAG",
+	CLIENT_CONNECT_WITH_DB:                "CLIENT_CONNECT_WITH_DB",
+	CLIENT_NO_SCHEMA:                      "CLIENT_NO_SCHEMA",
+	CLIENT_COMPRESS:                       "CLIENT_COMPRESS",
+	CLIENT_ODBC:                           "CLIENT_ODBC",
+	CLIENT_LOCAL_FILES:                    "CLIENT_LOCAL_FILES",
+	CLIENT_IGNORE_SPACE:                   "CLIENT_IGNORE_SPACE",
+	CLIENT_PROTOCOL_41:                    "CLIENT_PROTOCOL_41",
+	CLIENT_INTERACTIVE:                    "CLIENT_INTERACTIVE",
+	CLIENT_SSL:                            "CLIENT_SSL",
+	CLIENT_IGNORE_SIGPIPE:                 "CLIENT_IGNORE_SIGPIPE",
+	CLIENT_TRANSACTIONS:                   "CLIENT_TRANSACTIONS",
+	CLIENT_RESERVED:                       "CLIENT_RESERVED",
+	CLIENT_SECURE_CONNECTION:              "CLIENT_SECURE_CONNECTION",
+	CLIENT_MULTI_STATEMENTS:               "CLIENT_MULTI_STATEMENTS",
+	CLIENT_MULTI_RESULTS:                  "CLIENT_MULTI_RESULTS",
+	CLIENT_PS_MULTI_RESULTS:               "CLIENT_PS_MULTI_RESULTS",
+	CLIENT_PLUGIN_AUTH:                    "CLIENT_PLUGIN_AUTH",
+	CLIENT_CONNECT_ATTRS:                  "CLIENT_CONNECT_ATTRS",
+	CLIENT_PLUGIN_AUTH_LENENC_CLIENT_DATA: "CLIENT_PLUGIN_AUTH_LENENC_CLIENT_DATA",
+	CLIENT_CAN_HANDLE_EXPIRED_PASSWORDS:   "CLIENT_CAN_HANDLE_EXPIRED_PASSWORDS",
+	CLIENT_SESSION_TRACK:                  "CLIENT_SESSION_TRACK",
+	CLIENT_DEPRECATE_EOF:                  "CLIENT_DEPRECATE_EOF",
+	CLIENT_OPTIONAL_RESULTSET_METADATA:    "CLIENT_OPTIONAL_RESULTSET_METADATA",
+	CLIENT_ZSTD_COMPRESSION_ALGORITHM:     "CLIENT_ZSTD_COMPRESSION_ALGORITHM",
+	CLIENT_QUERY_ATTRIBUTES:               "CLIENT_QUERY_ATTRIBUTES",
+	MULTI_FACTOR_AUTHENTICATION:           "MULTI_FACTOR_AUTHENTICATION",
+	CLIENT_CAPABILITY_EXTENSION:           "CLIENT_CAPABILITY_EXTENSION",
+	CLIENT_SSL_VERIFY_SERVER_CERT:         "CLIENT_SSL_VERIFY_SERVER_CERT",
+	CLIENT_REMEMBER_OPTIONS:               "CLIENT_REMEMBER_OPTIONS",
+}
+
 const (
 	MYSQL_TYPE_DECIMAL byte = iota
 	MYSQL_TYPE_TINY