main.go: support to generate multiple custom dats (#3367)

This allows to remove any unwanted lists without modifying the domains
data, and you can generate multiple custom v2ray dat files in a single
command.

As long as the source data is consistent, any list remains in the trimed
dat contains the same rules comparing to the list in full dat.

Use the new option `datprofile` to specify the config json file path.
`outputname` will be ignored when `datprofile` is set.

Co-authored-by: database64128 <free122448@hotmail.com>

.gitignore

@@ -4,9 +4,9 @@
 /domain-list-community
 /domain-list-community.exe
 
-# Generated dat file.
-dlc.dat
+# Generated dat files.
+/*.dat
 
 # Exported plaintext lists.
-/*.yml
 /*.txt
+/*.yml

main.go

@@ -2,6 +2,7 @@ package main
 
 import (
 	"bufio"
+	"encoding/json"
 	"flag"
 	"fmt"
 	"os"
@@ -19,6 +20,7 @@ var (
 	dataPath    = flag.String("datapath", "./data", "Path to your custom 'data' directory")
 	outputName  = flag.String("outputname", "dlc.dat", "Name of the generated dat file")
 	outputDir   = flag.String("outputdir", "./", "Directory to place all generated files")
+	datProfile  = flag.String("datprofile", "", "Path of config file used to assemble custom dats")
 	exportLists = flag.String("exportlists", "", "Lists to be flattened and exported in plaintext format, separated by ',' comma")
 )
 
@@ -47,6 +49,23 @@ type Processor struct {
 	cirIncMap map[string]bool
 }
 
+type GeoSites struct {
+	Sites   []*router.GeoSite
+	SiteIdx map[string]int
+}
+
+type DatTask struct {
+	Name  string   `json:"name"`
+	Mode  string   `json:"mode"`
+	Lists []string `json:"lists"`
+}
+
+const (
+	ModeAll       string = "all"
+	ModeAllowlist string = "allowlist"
+	ModeDenylist  string = "denylist"
+)
+
 func makeProtoList(listName string, entries []*Entry) *router.GeoSite {
 	site := &router.GeoSite{
 		CountryCode: listName,
@@ -76,6 +95,90 @@ func makeProtoList(listName string, entries []*Entry) *router.GeoSite {
 	return site
 }
 
+func loadTasks(path string) ([]DatTask, error) {
+	f, err := os.Open(path)
+	if err != nil {
+		return nil, err
+	}
+	defer f.Close()
+
+	var tasks []DatTask
+	dec := json.NewDecoder(f)
+	if err := dec.Decode(&tasks); err != nil {
+		return nil, fmt.Errorf("failed to decode json: %w", err)
+	}
+	for i, t := range tasks {
+		if t.Name == "" {
+			return nil, fmt.Errorf("task[%d]: name is required", i)
+		}
+		switch t.Mode {
+		case ModeAll, ModeAllowlist, ModeDenylist:
+		default:
+			return nil, fmt.Errorf("task[%d] %q: invalid mode %q", i, t.Name, t.Mode)
+		}
+	}
+	return tasks, nil
+}
+
+func (gs *GeoSites) assembleDat(task DatTask) error {
+	datFileName := strings.ToLower(filepath.Base(task.Name))
+	geoSiteList := new(router.GeoSiteList)
+
+	switch task.Mode {
+	case ModeAll:
+		geoSiteList.Entry = gs.Sites
+	case ModeAllowlist:
+		allowedIdxes := make([]int, 0, len(task.Lists))
+		for _, list := range task.Lists {
+			if idx, ok := gs.SiteIdx[strings.ToUpper(list)]; ok {
+				allowedIdxes = append(allowedIdxes, idx)
+			} else {
+				return fmt.Errorf("list %q not found for allowlist task", list)
+			}
+		}
+		slices.Sort(allowedIdxes)
+		allowedlen := len(allowedIdxes)
+		if allowedlen == 0 {
+			return fmt.Errorf("allowlist needs at least one valid list")
+		}
+		geoSiteList.Entry = make([]*router.GeoSite, allowedlen)
+		for i, idx := range allowedIdxes {
+			geoSiteList.Entry[i] = gs.Sites[idx]
+		}
+	case ModeDenylist:
+		deniedMap := make(map[int]bool, len(task.Lists))
+		for _, list := range task.Lists {
+			if idx, ok := gs.SiteIdx[strings.ToUpper(list)]; ok {
+				deniedMap[idx] = true
+			} else {
+				fmt.Printf("[Warn] list %q not found in denylist task %q", list, task.Name)
+			}
+		}
+		deniedlen := len(deniedMap)
+		if deniedlen == 0 {
+			fmt.Printf("[Warn] nothing to deny in task %q", task.Name)
+			geoSiteList.Entry = gs.Sites
+		} else {
+			geoSiteList.Entry = make([]*router.GeoSite, 0, len(gs.Sites)-deniedlen)
+			for i, site := range gs.Sites {
+				if !deniedMap[i] {
+					geoSiteList.Entry = append(geoSiteList.Entry, site)
+				}
+			}
+		}
+	}
+
+	protoBytes, err := proto.Marshal(geoSiteList)
+	if err != nil {
+		return fmt.Errorf("failed to marshal: %w", err)
+	}
+	if err := os.WriteFile(filepath.Join(*outputDir, datFileName), protoBytes, 0644); err != nil {
+		return fmt.Errorf("failed to write file %q: %w", datFileName, err)
+	}
+	fmt.Printf("dat %q has been generated successfully\n", datFileName)
+	return nil
+}
+
 func writePlainList(listname string, entries []*Entry) error {
 	file, err := os.Create(filepath.Join(*outputDir, strings.ToLower(listname)+".txt"))
 	if err != nil {
@@ -443,25 +546,39 @@ func run() error {
 		}
 	}
 
-	// Generate dat file
-	protoList := &router.GeoSiteList{Entry: make([]*router.GeoSite, 0, sitesCount)}
+	// Generate proto sites
+	gs := &GeoSites{
+		Sites:   make([]*router.GeoSite, 0, sitesCount),
+		SiteIdx: make(map[string]int, sitesCount),
+	}
 	for siteName, siteEntries := range processor.finalMap {
-		protoList.Entry = append(protoList.Entry, makeProtoList(siteName, siteEntries))
+		gs.Sites = append(gs.Sites, makeProtoList(siteName, siteEntries))
 	}
 	processor = nil
-	// Sort protoList so the marshaled list is reproducible
-	slices.SortFunc(protoList.Entry, func(a, b *router.GeoSite) int {
+	// Sort proto sites so the generated file is reproducible
+	slices.SortFunc(gs.Sites, func(a, b *router.GeoSite) int {
 		return strings.Compare(a.CountryCode, b.CountryCode)
 	})
+	for i := range sitesCount {
+		gs.SiteIdx[gs.Sites[i].CountryCode] = i
+	}
 
-	protoBytes, err := proto.Marshal(protoList)
-	if err != nil {
-		return fmt.Errorf("failed to marshal: %w", err)
+	// Load tasks and generate dat files
+	var tasks []DatTask
+	if *datProfile == "" {
+		tasks = []DatTask{{Name: *outputName, Mode: ModeAll}}
+	} else {
+		var err error
+		tasks, err = loadTasks(*datProfile)
+		if err != nil {
+			return fmt.Errorf("failed to loadTasks %q: %v", *datProfile, err)
+		}
 	}
-	if err := os.WriteFile(filepath.Join(*outputDir, *outputName), protoBytes, 0644); err != nil {
-		return fmt.Errorf("failed to write output: %w", err)
+	for _, task := range tasks {
+		if err := gs.assembleDat(task); err != nil {
+			fmt.Printf("[Error] failed to assembleDat %q: %v", task.Name, err)
+		}
 	}
-	fmt.Printf("%q has been generated successfully\n", *outputName)
 	return nil
 }