code review fixes

Author: S.Kulish

hw07_file_copying/copy.go

@@ -2,13 +2,14 @@ package main
 
 import (
 	"errors"
+	"fmt"
 	"github.com/cheggaaa/pb"
 	"io"
 	"os"
 )
 
 var (
-	ErrUnsupportedFile       = errors.New("unsupported file")
+	// ErrUnsupportedFile       = errors.New("unsupported file")
 	ErrOffsetExceedsFileSize = errors.New("offset exceeds file size")
 	ErrTheSameFile           = errors.New("you are trying to rewrite the source file")
 )
@@ -19,23 +20,22 @@ func Copy(fromPath, toPath string, offset, limit int64) error {
 	}
 
 	inFile, err := os.Open(fromPath)
-
 	if err != nil {
-		return err
+		return fmt.Errorf("open input file: %w", err)
 	}
 
+	defer inFile.Close()
+
 	fileStat, err := os.Stat(fromPath)
 	if err != nil {
-		return err
+		return fmt.Errorf("read input file info: %w", err)
 	}
 
 	fileSize := fileStat.Size()
 	if fileSize < offset {
 		return ErrOffsetExceedsFileSize
 	}
 
-	defer inFile.Close()
-
 	if limit == 0 {
 		limit = fileSize
 	}
@@ -45,9 +45,8 @@ func Copy(fromPath, toPath string, offset, limit int64) error {
 	}
 
 	outFile, err := os.Create(toPath)
-
 	if err != nil {
-		return err
+		return fmt.Errorf("open output file: %w", err)
 	}
 
 	defer outFile.Close()
@@ -61,7 +60,10 @@ func Copy(fromPath, toPath string, offset, limit int64) error {
 
 	reader := bar.NewProxyReader(inFile)
 
-	io.CopyN(outFile, reader, limit)
+	_, err = io.CopyN(outFile, reader, limit)
+	if err != nil {
+		return fmt.Errorf("copy data to file: %w", err)
+	}
 
 	bar.Finish()
 

hw07_file_copying/copy_test.go

@@ -33,21 +33,27 @@ func TestCopy(t *testing.T) {
 	err = Copy("testdata/input.txt", "/tmp/offset_is_bigger_then_file_size.txt", 100000, 0)
 	require.Error(t, err)
 
-	Copy("testdata/input.txt", "/tmp/copy_offset0_limit0.txt", 0, 0)
+	err = Copy("testdata/input.txt", "/tmp/copy_offset0_limit0.txt", 0, 0)
+	require.NoError(t, err)
 	require.Equal(t, FileMD5("testdata/out_offset0_limit0.txt"), FileMD5("/tmp/copy_offset0_limit0.txt"))
 
-	Copy("testdata/input.txt", "/tmp/copy_offset0_limit10.txt", 0, 10)
+	err = Copy("testdata/input.txt", "/tmp/copy_offset0_limit10.txt", 0, 10)
+	require.NoError(t, err)
 	require.Equal(t, FileMD5("testdata/out_offset0_limit10.txt"), FileMD5("/tmp/copy_offset0_limit10.txt"))
 
-	Copy("testdata/input.txt", "/tmp/copy_offset0_limit1000.txt", 0, 1000)
+	err = Copy("testdata/input.txt", "/tmp/copy_offset0_limit1000.txt", 0, 1000)
+	require.NoError(t, err)
 	require.Equal(t, FileMD5("testdata/out_offset0_limit1000.txt"), FileMD5("/tmp/copy_offset0_limit1000.txt"))
 
-	Copy("testdata/input.txt", "/tmp/copy_offset0_limit10000.txt", 0, 10000)
+	err = Copy("testdata/input.txt", "/tmp/copy_offset0_limit10000.txt", 0, 10000)
+	require.NoError(t, err)
 	require.Equal(t, FileMD5("testdata/out_offset0_limit10000.txt"), FileMD5("/tmp/copy_offset0_limit10000.txt"))
 
-	Copy("testdata/input.txt", "/tmp/copy_offset100_limit1000.txt", 100, 1000)
+	err = Copy("testdata/input.txt", "/tmp/copy_offset100_limit1000.txt", 100, 1000)
+	require.NoError(t, err)
 	require.Equal(t, FileMD5("testdata/out_offset100_limit1000.txt"), FileMD5("/tmp/copy_offset100_limit1000.txt"))
 
-	Copy("testdata/input.txt", "/tmp/copy_offset6000_limit1000.txt", 6000, 1000)
+	err = Copy("testdata/input.txt", "/tmp/copy_offset6000_limit1000.txt", 6000, 1000)
+	require.NoError(t, err)
 	require.Equal(t, FileMD5("testdata/out_offset6000_limit1000.txt"), FileMD5("/tmp/copy_offset6000_limit1000.txt"))
 }

hw07_file_copying/main.go

@@ -18,5 +18,5 @@ func init() {
 
 func main() {
 	flag.Parse()
-	Copy(from, to, offset, limit)
+ 	Copy(from, to, offset, limit)
 }