feat: support convert mrs format back to text format

rules/provider/domain_strategy.go

@@ -9,6 +9,8 @@ import (
 	C "github.com/metacubex/mihomo/constant"
 	P "github.com/metacubex/mihomo/constant/provider"
 	"github.com/metacubex/mihomo/log"
+
+	"golang.org/x/exp/slices"
 )
 
 type domainStrategy struct {
@@ -78,6 +80,26 @@ func (d *domainStrategy) WriteMrs(w io.Writer) error {
 	return d.domainSet.WriteBin(w)
 }
 
+func (d *domainStrategy) DumpMrs(f func(key string) bool) {
+	if d.domainSet != nil {
+		var keys []string
+		d.domainSet.Foreach(func(key string) bool {
+			keys = append(keys, key)
+			return true
+		})
+		slices.Sort(keys)
+
+		for _, key := range keys {
+			if _, ok := slices.BinarySearch(keys, "+."+key); ok {
+				continue // ignore the rules added by trie internal processing
+			}
+			if !f(key) {
+				return
+			}
+		}
+	}
+}
+
 var _ mrsRuleStrategy = (*domainStrategy)(nil)
 
 func NewDomainStrategy() *domainStrategy {

rules/provider/ipcidr_strategy.go

@@ -3,6 +3,7 @@ package provider
 import (
 	"errors"
 	"io"
+	"net/netip"
 
 	"github.com/metacubex/mihomo/component/cidr"
 	C "github.com/metacubex/mihomo/constant"
@@ -82,6 +83,14 @@ func (i *ipcidrStrategy) WriteMrs(w io.Writer) error {
 	return i.cidrSet.WriteBin(w)
 }
 
+func (i *ipcidrStrategy) DumpMrs(f func(key string) bool) {
+	if i.cidrSet != nil {
+		i.cidrSet.Foreach(func(prefix netip.Prefix) bool {
+			return f(prefix.String())
+		})
+	}
+}
+
 func (i *ipcidrStrategy) ToIpCidr() *netipx.IPSet {
 	return i.cidrSet.ToIPSet()
 }

rules/provider/mrs_converter.go

@@ -3,6 +3,7 @@ package provider
 import (
 	"encoding/binary"
 	"errors"
+	"fmt"
 	"io"
 	"os"
 
@@ -21,6 +22,17 @@ func ConvertToMrs(buf []byte, behavior P.RuleBehavior, format P.RuleFormat, w io
 		return errors.New("empty rule")
 	}
 	if _strategy, ok := strategy.(mrsRuleStrategy); ok {
+		if format == P.MrsRule { // export to TextRule
+			_strategy.DumpMrs(func(key string) bool {
+				_, err = fmt.Fprintln(w, key)
+				if err != nil {
+					return false
+				}
+				return true
+			})
+			return nil
+		}
+
 		var encoder *zstd.Encoder
 		encoder, err = zstd.NewWriter(w)
 		if err != nil {

rules/provider/provider.go

@@ -58,6 +58,7 @@ type mrsRuleStrategy interface {
 	ruleStrategy
 	FromMrs(r io.Reader, count int) error
 	WriteMrs(w io.Writer) error
+	DumpMrs(f func(key string) bool)
 }
 
 func (rp *ruleSetProvider) Type() P.ProviderType {