Backup support

internal/buffer/backup.go

@@ -2,19 +2,51 @@ package buffer
 
 import (
 	"io"
+	"log"
+	"os"
+	"time"
 
 	"github.com/zyedidia/micro/internal/config"
 	"github.com/zyedidia/micro/internal/util"
 	"golang.org/x/text/encoding"
 )
 
+const backupMsg = `A backup was detected for this file. This likely means that micro
+crashed while editing this file, or another instance of micro is currently
+editing this file.
+
+The backup was created at %s.
+
+* 'recover' will apply the backup as unsaved changes to the current buffer.
+  When the buffer is closed, the backup will be removed.
+* 'ignore' will ignore the backup, discarding its changes. The backup file
+  will be removed.
+
+Options: [r]ecover, [i]gnore: `
+
 // Backup saves the current buffer to ConfigDir/backups
 func (b *Buffer) Backup() error {
 	if !b.Settings["backup"].(bool) {
 		return nil
 	}
 
-	name := config.ConfigDir + "/backups" + util.EscapePath(b.AbsPath)
+	sub := time.Now().Sub(b.lastbackup)
+	if sub < time.Duration(backup_time)*time.Millisecond {
+		log.Println("Backup event but not enough time has passed", sub)
+		return nil
+	}
+
+	b.lastbackup = time.Now()
+
+	backupdir := config.ConfigDir + "/backups/"
+	if _, err := os.Stat(backupdir); os.IsNotExist(err) {
+		os.Mkdir(backupdir, os.ModePerm)
+		log.Println("Creating backup dir")
+	}
+
+	name := backupdir + util.EscapePath(b.AbsPath)
+
+	log.Println("Backing up to", name)
 
 	err := overwriteFile(name, encoding.Nop, func(file io.Writer) (e error) {
 		if len(b.lines) == 0 {
@@ -43,6 +75,15 @@ func (b *Buffer) Backup() error {
 	return err
 }
 
+// RemoveBackup removes any backup file associated with this buffer
+func (b *Buffer) RemoveBackup() {
+	if !b.Settings["backup"].(bool) {
+		return
+	}
+	f := config.ConfigDir + "/backups/" + util.EscapePath(b.AbsPath)
+	os.Remove(f)
+}
+
 // ApplyBackup applies the corresponding backup file to this buffer (if one exists)
 func (b *Buffer) ApplyBackup() error {
 	return nil

internal/buffer/buffer.go

@@ -4,8 +4,10 @@ import (
 	"bytes"
 	"crypto/md5"
 	"errors"
+	"fmt"
 	"io"
 	"io/ioutil"
+	"log"
 	"os"
 	"path/filepath"
 	"strconv"
@@ -25,6 +27,8 @@ import (
 	"golang.org/x/text/transform"
 )
 
+const backup_time = 8000
+
 var (
 	OpenBuffers []*Buffer
 	LogBuf      *Buffer
@@ -109,6 +113,10 @@ type Buffer struct {
 	CurSuggestion int
 
 	Messages []*Message
+
+	// counts the number of edits
+	// resets every backup_time edits
+	lastbackup time.Time
 }
 
 // NewBufferFromFile opens a new buffer using the given path
@@ -191,9 +199,36 @@ func NewBuffer(r io.Reader, size int64, path string, startcursor Loc, btype BufT
 	}
 
 	if !found {
+		choice := 1 // ignore by default
+
 		b.SharedBuffer = new(SharedBuffer)
 		b.Type = btype
-		b.LineArray = NewLineArray(uint64(size), FFAuto, reader)
+
+		if b.Settings["backup"].(bool) {
+			backupfile := config.ConfigDir + "/backups/" + EscapePath(absPath)
+			if info, err := os.Stat(backupfile); err == nil {
+				backup, err := os.Open(backupfile)
+				if err == nil {
+					t := info.ModTime()
+					msg := fmt.Sprintf(backupMsg, t.Format("Mon Jan _2 15:04 2006"))
+					choice = screen.TermPrompt(msg, []string{"r", "i", "recover", "ignore"}, true)
+					log.Println("Choice:", choice)
+
+					if choice%2 == 0 {
+						// recover
+						b.LineArray = NewLineArray(uint64(size), FFAuto, backup)
+					} else if choice%2 == 1 {
+						// delete
+						os.Remove(backupfile)
+					}
+					backup.Close()
+				}
+			}
+		}
+
+		if choice > 0 {
+			b.LineArray = NewLineArray(uint64(size), FFAuto, reader)
+		}
 		b.EventHandler = NewEventHandler(b.SharedBuffer, b.cursors)
 	}
 
@@ -273,6 +308,7 @@ func (b *Buffer) Fini() {
 	if !b.Modified() {
 		b.Serialize()
 	}
+	b.RemoveBackup()
 }
 
 // GetName returns the name that should be displayed in the statusline
@@ -297,6 +333,8 @@ func (b *Buffer) Insert(start Loc, text string) {
 		b.EventHandler.cursors = b.cursors
 		b.EventHandler.active = b.curCursor
 		b.EventHandler.Insert(start, text)
+
+		go b.Backup()
 	}
 }
 
@@ -305,6 +343,8 @@ func (b *Buffer) Remove(start, end Loc) {
 		b.EventHandler.cursors = b.cursors
 		b.EventHandler.active = b.curCursor
 		b.EventHandler.Remove(start, end)
+
+		go b.Backup()
 	}
 }
 

internal/screen/message.go

@@ -5,6 +5,7 @@ import (
 	"fmt"
 	"os"
 	"strconv"
+	"strings"
 )
 
 // TermMessage sends a message to the user in the terminal. This usually occurs before
@@ -25,6 +26,38 @@ func TermMessage(msg ...interface{}) {
 	TempStart(screenb)
 }
 
+// TermPrompt prints a prompt and requests the user for a response
+// The result is matched against a list of options and the index of
+// the match is returned
+// If wait is true, the prompt re-prompts until a valid option is
+// chosen, otherwise if wait is false, -1 is returned for no match
+func TermPrompt(prompt string, options []string, wait bool) int {
+	screenb := TempFini()
+
+	idx := -1
+	// same behavior as do { ... } while (wait && idx == -1)
+	for ok := true; ok; ok = wait && idx == -1 {
+		reader := bufio.NewReader(os.Stdin)
+		fmt.Print(prompt)
+		resp, _ := reader.ReadString('\n')
+		resp = strings.TrimSpace(resp)
+
+		for i, opt := range options {
+			if resp == opt {
+				idx = i
+			}
+		}
+
+		if wait && idx == -1 {
+			fmt.Println("\nInvalid choice.")
+		}
+	}
+
+	TempStart(screenb)
+
+	return idx
+}
+
 // TermError sends an error to the user in the terminal. Like TermMessage except formatted
 // as an error
 func TermError(filename string, lineNum int, err string) {