From 63eb070e78d6603752f5d065fa2e0b14af4afc1d Mon Sep 17 00:00:00 2001
From: Christian Zangl <laktak@cdak.net>
Date: Sun, 22 Dec 2024 19:12:22 +0100
Subject: [PATCH] implement db export to json

---
 README.md          |  3 ++
 cmd/chkbit/main.go | 11 ++++++
 store.go           | 86 +++++++++++++++++++++++++++++++++++++++-------
 3 files changed, 87 insertions(+), 13 deletions(-)

diff --git a/README.md b/README.md
index ec0066f..ecd29e7 100644
--- a/README.md
+++ b/README.md
@@ -122,6 +122,9 @@ Commands:
   init-db <path> [flags]
     initialize a new index database at the given path for use with --db
 
+  export-db <path> [flags]
+    export a database to a json for archiving
+
   show-ignored-only <paths> ... [flags]
     only show ignored files
 
diff --git a/cmd/chkbit/main.go b/cmd/chkbit/main.go
index 259821f..a176238 100644
--- a/cmd/chkbit/main.go
+++ b/cmd/chkbit/main.go
@@ -67,6 +67,10 @@ type CLI struct {
 		Force bool   `help:"force init if a database already exists"`
 	} `cmd:"" help:"initialize a new index database at the given path for use with --db"`
 
+	ExportDb struct {
+		Path string `arg:"" help:"directory for the database"`
+	} `cmd:"" help:"export a database to a json for archiving"`
+
 	ShowIgnoredOnly struct {
 		Paths []string `arg:""  name:"paths" help:"directories to list"`
 	} `cmd:"" help:"only show ignored files"`
@@ -377,6 +381,13 @@ func (m *Main) run() int {
 			return 1
 		}
 		return 0
+	case "export-db <path>":
+		m.log("chkbit export-db " + cli.ExportDb.Path)
+		if err := chkbit.ExportIndexDb(cli.ExportDb.Path, cli.IndexName); err != nil {
+			fmt.Println("error: " + err.Error())
+			return 1
+		}
+		return 0
 	case "tips":
 		fmt.Println(strings.ReplaceAll(helpTips, "<config-file>", configPath))
 		return 0
diff --git a/store.go b/store.go
index 223e7ff..48054fa 100644
--- a/store.go
+++ b/store.go
@@ -1,6 +1,7 @@
 package chkbit
 
 import (
+	"encoding/json"
 	"errors"
 	"io"
 	"os"
@@ -38,19 +39,8 @@ func (s *store) Open(readOnly bool) error {
 	var err error
 	s.readOnly = readOnly
 	if s.useDb {
-		optR := &bolt.Options{
-			ReadOnly:     true,
-			Timeout:      0,
-			NoGrowSync:   false,
-			FreelistType: bolt.FreelistArrayType,
-		}
-		optW := &bolt.Options{
-			Timeout:      0,
-			NoGrowSync:   false,
-			FreelistType: bolt.FreelistArrayType,
-		}
 		s.dbFile = getDbFile(s.dbPath, s.indexName, "")
-		s.connR, err = bolt.Open(s.dbFile, 0600, optR)
+		s.connR, err = bolt.Open(s.dbFile, 0600, getBoltOptions(true))
 
 		if !readOnly {
 			s.newFile = getDbFile(s.dbPath, s.indexName, newDbSuffix)
@@ -64,7 +54,7 @@ func (s *store) Open(readOnly bool) error {
 				return err
 			}
 
-			s.connW, err = bolt.Open(s.newFile, 0600, optW)
+			s.connW, err = bolt.Open(s.newFile, 0600, getBoltOptions(false))
 			if err == nil {
 				err = s.connW.Update(func(tx *bolt.Tx) error {
 					_, err := tx.CreateBucketIfNotExists([]byte("data"))
@@ -188,6 +178,67 @@ func LocateIndexDb(path, indexName string) (string, error) {
 	}
 }
 
+func ExportIndexDb(path, indexName string) error {
+
+	dbFile := getDbFile(path, indexName, "")
+	connR, err := bolt.Open(dbFile, 0600, getBoltOptions(true))
+	if err != nil {
+		return err
+	}
+
+	file, err := os.Create(getDbFile(path, indexName, ".json"))
+	if err != nil {
+		return err
+	}
+	defer file.Close() // Ensure the file is closed when the function exits
+
+	_, err = file.WriteString("{")
+	if err != nil {
+		return err
+	}
+
+	err = connR.View(func(tx *bolt.Tx) error {
+		b := tx.Bucket([]byte("data"))
+		c := b.Cursor()
+		var ierr error
+		first := true
+		for k, v := c.First(); k != nil; k, v = c.Next() {
+
+			if first {
+				first = false
+			} else {
+				if _, ierr = file.WriteString(","); ierr != nil {
+					break
+				}
+			}
+
+			if idxPath, ierr := json.Marshal(string(k)); ierr == nil {
+				if _, ierr = file.Write(idxPath); ierr != nil {
+					break
+				}
+			} else {
+				break
+			}
+
+			if _, ierr = file.WriteString(":"); ierr != nil {
+				break
+			}
+
+			if _, ierr = file.Write(v); ierr != nil {
+				break
+			}
+		}
+		return ierr
+	})
+
+	_, err = file.WriteString("}")
+	if err != nil {
+		return err
+	}
+
+	return err
+}
+
 func getDbFile(path, indexFilename, suffix string) string {
 	return filepath.Join(path, indexFilename+dbSuffix+suffix)
 }
@@ -217,3 +268,12 @@ func copyFile(src, dst string) error {
 	_, err = io.Copy(df, sf)
 	return err
 }
+
+func getBoltOptions(readOnly bool) *bolt.Options {
+	return &bolt.Options{
+		ReadOnly:     readOnly,
+		Timeout:      0,
+		NoGrowSync:   false,
+		FreelistType: bolt.FreelistArrayType,
+	}
+}