fs: re-implement CutoffMode, LogLevel, TerminalColorMode with Enum

This almost 100% backwards compatible. The only difference being that
in the rc options/get output CutoffMode, LogLevel, TerminalColorMode
will be output as strings instead of integers. This is a lot more
convenient for the user. They still accept integer inputs though so
the fallout from this should be minimal.

fs/cutoffmode.go

@@ -1,58 +1,22 @@
 package fs
 
-import (
-	"fmt"
-	"strings"
-)
+type cutoffModeChoices struct{}
+
+func (cutoffModeChoices) Choices() []string {
+	return []string{
+		CutoffModeHard:     "HARD",
+		CutoffModeSoft:     "SOFT",
+		CutoffModeCautious: "CAUTIOUS",
+	}
+}
 
 // CutoffMode describes the possible delete modes in the config
-type CutoffMode byte
+type CutoffMode = Enum[cutoffModeChoices]
 
-// MaxTransferMode constants
+// CutoffMode constants
 const (
 	CutoffModeHard CutoffMode = iota
 	CutoffModeSoft
 	CutoffModeCautious
 	CutoffModeDefault = CutoffModeHard
 )
-
-var cutoffModeToString = []string{
-	CutoffModeHard:     "HARD",
-	CutoffModeSoft:     "SOFT",
-	CutoffModeCautious: "CAUTIOUS",
-}
-
-// String turns a LogLevel into a string
-func (m CutoffMode) String() string {
-	if m >= CutoffMode(len(cutoffModeToString)) {
-		return fmt.Sprintf("CutoffMode(%d)", m)
-	}
-	return cutoffModeToString[m]
-}
-
-// Set a LogLevel
-func (m *CutoffMode) Set(s string) error {
-	for n, name := range cutoffModeToString {
-		if s != "" && name == strings.ToUpper(s) {
-			*m = CutoffMode(n)
-			return nil
-		}
-	}
-	return fmt.Errorf("unknown cutoff mode %q", s)
-}
-
-// Type of the value
-func (m CutoffMode) Type() string {
-	return "string"
-}
-
-// UnmarshalJSON makes sure the value can be parsed as a string or integer in JSON
-func (m *CutoffMode) UnmarshalJSON(in []byte) error {
-	return UnmarshalJSONFlag(in, m, func(i int64) error {
-		if i < 0 || i >= int64(len(cutoffModeToString)) {
-			return fmt.Errorf("out of range cutoff mode %d", i)
-		}
-		*m = (CutoffMode)(i)
-		return nil
-	})
-}

fs/cutoffmode_test.go

@@ -22,7 +22,7 @@ func TestCutoffModeString(t *testing.T) {
 	}{
 		{CutoffModeHard, "HARD"},
 		{CutoffModeSoft, "SOFT"},
-		{99, "CutoffMode(99)"},
+		{99, "Unknown(99)"},
 	} {
 		cm := test.in
 		got := cm.String()

fs/enum.go

@@ -91,14 +91,17 @@ func (e *Enum[C]) Scan(s fmt.ScanState, ch rune) error {
 	return e.Set(string(token))
 }
 
-// UnmarshalJSON parses it as a string
+// UnmarshalJSON parses it as a string or an integer
 func (e *Enum[C]) UnmarshalJSON(in []byte) error {
-	var choice string
-	err := json.Unmarshal(in, &choice)
-	if err != nil {
-		return err
+	choices := e.Choices()
+	return UnmarshalJSONFlag(in, e, func(i int64) error {
+		if i < 0 || i >= int64(len(choices)) {
+			return fmt.Errorf("%d is out of range: must be 0..%d", i, len(choices))
 		}
-	return e.Set(choice)
+		*e = Enum[C](i)
+		return nil
+	})
+
 }
 
 // MarshalJSON encodes it as string

fs/enum_test.go

@@ -107,16 +107,20 @@ func TestEnumUnmarshalJSON(t *testing.T) {
 	for _, test := range []struct {
 		in   string
 		want choice
-		err  bool
+		err  string
 	}{
-		{`"A"`, choiceA, false},
-		{`"B"`, choiceB, false},
-		{`"D"`, choice(0), true},
+		{`"A"`, choiceA, ""},
+		{`"B"`, choiceB, ""},
+		{`0`, choiceA, ""},
+		{`1`, choiceB, ""},
+		{`"D"`, choice(0), `invalid choice "D" from: A, B, C`},
+		{`100`, choice(0), `100 is out of range: must be 0..3`},
 	} {
 		var got choice
 		err := json.Unmarshal([]byte(test.in), &got)
-		if test.err {
+		if test.err != "" {
 			require.Error(t, err, test.in)
+			assert.ErrorContains(t, err, test.err)
 		} else {
 			require.NoError(t, err, test.in)
 		}

fs/log.go

@@ -10,7 +10,7 @@ import (
 )
 
 // LogLevel describes rclone's logs.  These are a subset of the syslog log levels.
-type LogLevel byte
+type LogLevel = Enum[logLevelChoices]
 
 // Log levels.  These are the syslog levels of which we only use a
 // subset.
@@ -34,7 +34,10 @@ const (
 	LogLevelDebug  // Debug level, needs -vv
 )
 
-var logLevelToString = []string{
+type logLevelChoices struct{}
+
+func (logLevelChoices) Choices() []string {
+	return []string{
 		LogLevelEmergency: "EMERGENCY",
 		LogLevelAlert:     "ALERT",
 		LogLevelCritical:  "CRITICAL",
@@ -44,42 +47,12 @@ var logLevelToString = []string{
 		LogLevelInfo:      "INFO",
 		LogLevelDebug:     "DEBUG",
 	}
-
-// String turns a LogLevel into a string
-func (l LogLevel) String() string {
-	if l >= LogLevel(len(logLevelToString)) {
-		return fmt.Sprintf("LogLevel(%d)", l)
-	}
-	return logLevelToString[l]
 }
 
-// Set a LogLevel
-func (l *LogLevel) Set(s string) error {
-	for n, name := range logLevelToString {
-		if s != "" && name == s {
-			*l = LogLevel(n)
-			return nil
-		}
-	}
-	return fmt.Errorf("unknown log level %q", s)
-}
-
-// Type of the value
-func (l LogLevel) Type() string {
+func (logLevelChoices) Type() string {
 	return "LogLevel"
 }
 
-// UnmarshalJSON makes sure the value can be parsed as a string or integer in JSON
-func (l *LogLevel) UnmarshalJSON(in []byte) error {
-	return UnmarshalJSONFlag(in, l, func(i int64) error {
-		if i < 0 || i >= int64(LogLevel(len(logLevelToString))) {
-			return fmt.Errorf("unknown log level %d", i)
-		}
-		*l = (LogLevel)(i)
-		return nil
-	})
-}
-
 // LogPrintPid enables process pid in log
 var LogPrintPid = false
 

fs/log_test.go

@@ -39,7 +39,7 @@ func TestLogLevelString(t *testing.T) {
 	}{
 		{LogLevelEmergency, "EMERGENCY"},
 		{LogLevelDebug, "DEBUG"},
-		{99, "LogLevel(99)"},
+		{99, "Unknown(99)"},
 	} {
 		logLevel := test.in
 		got := logLevel.String()

fs/terminalcolormode.go

@@ -1,12 +1,7 @@
 package fs
 
-import (
-	"fmt"
-	"strings"
-)
-
 // TerminalColorMode describes how ANSI codes should be handled
-type TerminalColorMode byte
+type TerminalColorMode = Enum[terminalColorModeChoices]
 
 // TerminalColorMode constants
 const (
@@ -15,43 +10,12 @@ const (
 	TerminalColorModeAlways
 )
 
-var terminalColorModeToString = []string{
+type terminalColorModeChoices struct{}
+
+func (terminalColorModeChoices) Choices() []string {
+	return []string{
 		TerminalColorModeAuto:   "AUTO",
 		TerminalColorModeNever:  "NEVER",
 		TerminalColorModeAlways: "ALWAYS",
 	}
-
-// String converts a TerminalColorMode to a string
-func (m TerminalColorMode) String() string {
-	if m >= TerminalColorMode(len(terminalColorModeToString)) {
-		return fmt.Sprintf("TerminalColorMode(%d)", m)
-	}
-	return terminalColorModeToString[m]
-}
-
-// Set a TerminalColorMode
-func (m *TerminalColorMode) Set(s string) error {
-	for n, name := range terminalColorModeToString {
-		if s != "" && name == strings.ToUpper(s) {
-			*m = TerminalColorMode(n)
-			return nil
-		}
-	}
-	return fmt.Errorf("unknown terminal color mode %q", s)
-}
-
-// Type of TerminalColorMode
-func (m TerminalColorMode) Type() string {
-	return "string"
-}
-
-// UnmarshalJSON converts a string/integer in JSON to a TerminalColorMode
-func (m *TerminalColorMode) UnmarshalJSON(in []byte) error {
-	return UnmarshalJSONFlag(in, m, func(i int64) error {
-		if i < 0 || i >= int64(len(terminalColorModeToString)) {
-			return fmt.Errorf("out of range terminal color mode %d", i)
-		}
-		*m = (TerminalColorMode)(i)
-		return nil
-	})
 }

fs/terminalcolormode_test.go

@@ -17,7 +17,7 @@ func TestTerminalColorModeString(t *testing.T) {
 		{TerminalColorModeAuto, "AUTO"},
 		{TerminalColorModeAlways, "ALWAYS"},
 		{TerminalColorModeNever, "NEVER"},
-		{36, "TerminalColorMode(36)"},
+		{36, "Unknown(36)"},
 	} {
 		tcm := test.in
 		assert.Equal(t, test.want, tcm.String(), test.in)