cmd: Use readline library. (#98)

Using this library we have history out of the box.

Author: ajnavarro

Diff for: cmd/gitql/shell.go

@@ -1,11 +1,15 @@
 package main
 
 import (
-	"bufio"
-	"bytes"
 	"fmt"
-	"os"
 	"strings"
+
+	"github.com/chzyer/readline"
+)
+
+const (
+	initPrompt      = "!> "
+	multilinePrompt = "!>>> "
 )
 
 type CmdShell struct {
@@ -21,69 +25,56 @@ func (c *CmdShell) Execute(args []string) error {
 		return err
 	}
 
-	fmt.Print(`
+	rl, err := readline.NewEx(&readline.Config{
+		Prompt:                 initPrompt,
+		HistoryFile:            "/tmp/gitql-history",
+		DisableAutoSaveHistory: true,
+	})
+	if err != nil {
+		return err
+	}
+
+	rl.Terminal.Print(fmt.Sprint(`
            gitQL SHELL
            -----------
 You must end your queries with ';'
 
-`)
-
-	s := bufio.NewScanner(os.Stdin)
-
-	s.Split(scanQueries)
+`))
 
+	var cmds []string
 	for {
-		fmt.Print("!> ")
-
-		if !s.Scan() {
+		line, err := rl.Readline()
+		if err != nil {
 			break
 		}
+		line = strings.TrimSpace(line)
+		if len(line) == 0 {
+			continue
+		}
+		cmds = append(cmds, line)
+		if !strings.HasSuffix(line, ";") {
+			rl.SetPrompt(multilinePrompt)
+			continue
+		}
 
-		query := s.Text()
-
-		query = strings.Replace(query, "\n", " ", -1)
-		query = strings.TrimSpace(query)
+		query := strings.Join(cmds, " ")
+		cmds = cmds[:0]
+		rl.SetPrompt(initPrompt)
+		rl.SaveHistory(query)
 
-		fmt.Printf("\n--> Executing query: %s\n\n", query)
+		rl.Terminal.Print(fmt.Sprintf("\n--> Executing query: %s\n\n", query))
 
 		schema, rowIter, err := c.executeQuery(query)
 		if err != nil {
-			c.printError(err)
+			rl.Terminal.Print(fmt.Sprintf("ERROR: %v\n\n", err))
 			continue
 		}
 
 		if err := c.printQuery(schema, rowIter, "pretty"); err != nil {
-			c.printError(err)
+			rl.Terminal.Print(fmt.Sprintf("ERROR: %v\n\n", err))
+			continue
 		}
 	}
 
-	return s.Err()
-}
-
-func (c *CmdShell) printError(err error) {
-	fmt.Printf("ERROR: %v\n\n", err)
-}
-
-func scanQueries(data []byte, atEOF bool) (int, []byte, error) {
-	if atEOF && len(data) == 0 {
-		return 0, nil, nil
-	}
-	if i := bytes.IndexByte(data, ';'); i >= 0 {
-		// We have a full newline-terminated line.
-		return i + 1, dropCR(data[0:i]), nil
-	}
-	// If we're at EOF, we have a final, non-terminated line. Return it.
-	if atEOF {
-		return len(data), dropCR(data), nil
-	}
-	// Request more data.
-	return 0, nil, nil
-}
-
-// dropCR drops a terminal \r from the data.
-func dropCR(data []byte) []byte {
-	if len(data) > 0 && data[len(data)-1] == '\r' {
-		return data[0 : len(data)-1]
-	}
-	return data
+	return rl.Close()
 }