Add simple 'read-only' mode.

It just closes the database as soon as it's done loading it.
To refresh, you have to close out and reopen.

bolt_model.go

@@ -364,6 +364,9 @@ func addBucketFromBoltBucket(path []string, bb *BoltBucket) error {
 }
 
 func deleteKey(path []string) error {
+	if AppArgs.ReadOnly {
+		return errors.New("DB is in Read-Only Mode")
+	}
 	err := db.Update(func(tx *bolt.Tx) error {
 		// len(b.path)-1 is the key we need to delete,
 		// the rest are buckets leading to that key
@@ -469,6 +472,9 @@ func renameBucket(path []string, name string) error {
 }
 
 func updatePairKey(path []string, k string) error {
+	if AppArgs.ReadOnly {
+		return errors.New("DB is in Read-Only Mode")
+	}
 	err := db.Update(func(tx *bolt.Tx) error {
 		// len(b.path)-1 is the key for the pair we're updating,
 		// the rest are buckets leading to that key
@@ -498,6 +504,9 @@ func updatePairKey(path []string, k string) error {
 }
 
 func updatePairValue(path []string, v string) error {
+	if AppArgs.ReadOnly {
+		return errors.New("DB is in Read-Only Mode")
+	}
 	err := db.Update(func(tx *bolt.Tx) error {
 		// len(b.GetPath())-1 is the key for the pair we're updating,
 		// the rest are buckets leading to that key
@@ -521,6 +530,9 @@ func updatePairValue(path []string, v string) error {
 }
 
 func insertBucket(path []string, n string) error {
+	if AppArgs.ReadOnly {
+		return errors.New("DB is in Read-Only Mode")
+	}
 	// Inserts a new bucket named 'n' at 'path'
 	err := db.Update(func(tx *bolt.Tx) error {
 		if len(path) == 0 {
@@ -558,6 +570,9 @@ func insertBucket(path []string, n string) error {
 }
 
 func insertPair(path []string, k string, v string) error {
+	if AppArgs.ReadOnly {
+		return errors.New("DB is in Read-Only Mode")
+	}
 	// Insert a new pair k => v at path
 	err := db.Update(func(tx *bolt.Tx) error {
 		if len(path) == 0 {

boltbrowser.go

@@ -1,9 +1,10 @@
 package main
 
 import (
-	"flag"
+	"errors"
 	"fmt"
 	"os"
+	"strings"
 	"time"
 
 	"github.com/boltdb/bolt"
@@ -20,27 +21,79 @@ var currentFilename string
 
 const DefaultDBOpenTimeout = time.Second
 
-var args struct {
+var AppArgs struct {
 	DBOpenTimeout time.Duration
+	ReadOnly      bool
 }
 
 func init() {
-	flag.DurationVar(&args.DBOpenTimeout, "timeout", DefaultDBOpenTimeout, "DB file open timeout")
-	flag.Usage = func() {
-		fmt.Fprintf(os.Stderr, "Usage: %s [OPTIONS] <filename(s)>\nOptions:\n", ProgramName)
-		flag.PrintDefaults()
+	AppArgs.DBOpenTimeout = DefaultDBOpenTimeout
+	AppArgs.ReadOnly = false
+}
+
+func parseArgs() {
+	var err error
+	if len(os.Args) == 1 {
+		printUsage(nil)
 	}
+	parms := os.Args[1:]
+	for i := range parms {
+		// All 'option' arguments start with "-"
+		if !strings.HasPrefix(parms[i], "-") {
+			databaseFiles = append(databaseFiles, parms[i])
+			continue
+		}
+		if strings.Contains(parms[i], "=") {
+			// Key/Value pair Arguments
+			pts := strings.Split(parms[i], "=")
+			key, val := pts[0], pts[1]
+			switch key {
+			case "-timeout":
+				AppArgs.DBOpenTimeout, err = time.ParseDuration(val)
+				if err != nil {
+					// See if we can successfully parse by adding a 's'
+					AppArgs.DBOpenTimeout, err = time.ParseDuration(val + "s")
+				}
+				// If err is still not nil, print usage
+				if err != nil {
+					printUsage(err)
+				}
+			case "-readonly", "-ro":
+				if val == "true" {
+					AppArgs.ReadOnly = true
+				}
+			case "-help":
+				printUsage(nil)
+			default:
+				printUsage(errors.New("Invalid option"))
+			}
+		} else {
+			// Single-word arguments
+			switch parms[i] {
+			case "-readonly", "-ro":
+				AppArgs.ReadOnly = true
+			case "-help":
+				printUsage(nil)
+			default:
+				printUsage(errors.New("Invalid option"))
+			}
+		}
+	}
+}
+
+func printUsage(err error) {
+	if err != nil {
+		fmt.Fprintf(os.Stderr, err.Error())
+	}
+	fmt.Fprintf(os.Stderr, "Usage: %s [OPTIONS] <filename(s)>\nOptions:\n", ProgramName)
+	fmt.Fprintf(os.Stderr, "  -timeout=duration\n        DB file open timeout (default 1s)\n")
+	fmt.Fprintf(os.Stderr, "  -ro, -readonly   \n        Open the DB in read-only mode\n")
 }
 
 func main() {
 	var err error
 
-	flag.Parse()
-
-	if flag.NArg() == 0 {
-		flag.Usage()
-		os.Exit(2)
-	}
+	parseArgs()
 
 	err = termbox.Init()
 	if err != nil {
@@ -50,10 +103,9 @@ func main() {
 	style := defaultStyle()
 	termbox.SetOutputMode(termbox.Output256)
 
-	databaseFiles := flag.Args()
 	for _, databaseFile := range databaseFiles {
 		currentFilename = databaseFile
-		db, err = bolt.Open(databaseFile, 0600, &bolt.Options{Timeout: args.DBOpenTimeout})
+		db, err = bolt.Open(databaseFile, 0600, &bolt.Options{Timeout: AppArgs.DBOpenTimeout})
 		if err == bolt.ErrTimeout {
 			termbox.Close()
 			fmt.Printf("File %s is locked. Make sure it's not used by another app and try again\n", databaseFile)
@@ -65,12 +117,17 @@ func main() {
 			} else {
 				termbox.Close()
 				fmt.Printf("Error reading file: %q\n", err.Error())
-				os.Exit(111)
+				os.Exit(1)
 			}
 		}
 
 		// First things first, load the database into memory
 		memBolt.refreshDatabase()
+		if AppArgs.ReadOnly {
+			// If we're opening it in readonly mode, close it now
+			db.Close()
+		}
+
 		// Kick off the UI loop
 		mainLoop(memBolt, style)
 		defer db.Close()