all: simplify parsing statement for magic command get

This changes minimize code duplication when parsing magic command
between "#get:" and "#get!" using single function parseStatementGetPut.

In the returned Statement, we changes where to store the source argument
into args[0] instead of in cmd for better readability and minimize
confusion in Copy/SudoCopy.

While at it, we add unit test for "#get:".
Unit test for "#get!" is not possible right now, because it will prompt
for password.

1 files changed, 43 insertions, 20 deletions

diff --git a/statement.go b/statement.go
index 84071dd..4b8b1a2 100644
--- a/statement.go
+++ b/statement.go
@@ -5,6 +5,7 @@ package awwan
 
 import (
 	"bytes"
+	"errors"
 	"fmt"
 	"strings"
 
@@ -12,7 +13,7 @@ import (
 )
 
 const (
-	statementKindDefault = iota
+	statementKindDefault int = iota
 	statementKindComment
 	statementKindRequire
 	statementKindGet
@@ -21,6 +22,15 @@ const (
 	statementKindSudoPut
 )
 
+// List of magic command.
+var (
+	cmdMagicGet     = []byte(`#get:`)
+	cmdMagicPut     = []byte(`#put:`)
+	cmdMagicSudoGet = []byte(`#get!`)
+	cmdMagicSudoPut = []byte(`#put!`)
+	cmdMagicRequire = []byte(`#require:`)
+)
+
 // Statement contains parsed raw line from the script.
 type Statement struct {
 	cmd  string
@@ -33,7 +43,7 @@ type Statement struct {
 // It will return nil if raw line is empty.
 func ParseStatement(raw []byte) (stmt *Statement, err error) {
 	var (
-		logp = "ParseStatement"
+		logp = `ParseStatement`
 
 		cmd  string
 		args []string
@@ -46,15 +56,9 @@ func ParseStatement(raw []byte) (stmt *Statement, err error) {
 
 	if bytes.HasPrefix(raw, cmdMagicGet) {
 		raw = raw[len(cmdMagicGet):]
-		cmd, args = libexec.ParseCommandArgs(string(raw))
-		if len(cmd) == 0 || len(args) == 0 {
-			return nil, fmt.Errorf("%s: %s missing argument", logp, cmdMagicGet)
-		}
-		stmt = &Statement{
-			kind: statementKindGet,
-			cmd:  cmd,
-			args: args,
-			raw:  raw,
+		stmt, err = parseStatementGetPut(statementKindGet, raw)
+		if err != nil {
+			return nil, fmt.Errorf(`%s: %q: %w`, logp, cmdMagicGet, err)
 		}
 		return stmt, nil
 	}
@@ -74,15 +78,9 @@ func ParseStatement(raw []byte) (stmt *Statement, err error) {
 	}
 	if bytes.HasPrefix(raw, cmdMagicSudoGet) {
 		raw = raw[len(cmdMagicSudoGet):]
-		cmd, args = libexec.ParseCommandArgs(string(raw))
-		if len(cmd) == 0 || len(args) == 0 {
-			return nil, fmt.Errorf("%s: %s missing argument", logp, cmdMagicSudoGet)
-		}
-		stmt = &Statement{
-			kind: statementKindSudoGet,
-			cmd:  cmd,
-			args: args,
-			raw:  raw,
+		stmt, err = parseStatementGetPut(statementKindSudoGet, raw)
+		if err != nil {
+			return nil, fmt.Errorf(`%s: %q: %w`, logp, cmdMagicSudoGet, err)
 		}
 		return stmt, nil
 	}
@@ -131,3 +129,28 @@ func ParseStatement(raw []byte) (stmt *Statement, err error) {
 func (stmt *Statement) String() string {
 	return fmt.Sprintf("%s %s", stmt.cmd, strings.Join(stmt.args, " "))
 }
+
+// parseStatementGetPut parse the raw "#get" or "#put" statement.
+func parseStatementGetPut(kind int, raw []byte) (stmt *Statement, err error) {
+	var (
+		cmd  string
+		args []string
+	)
+
+	cmd, args = libexec.ParseCommandArgs(string(raw))
+	if len(cmd) == 0 {
+		return nil, errors.New(`missing arguments`)
+	}
+	if len(args) == 0 {
+		return nil, errors.New(`missing destination file`)
+	}
+	if len(args) > 1 {
+		return nil, errors.New(`too many arguments`)
+	}
+	stmt = &Statement{
+		kind: kind,
+		args: []string{cmd, args[0]},
+		raw:  raw,
+	}
+	return stmt, nil
+}