add method for checking gofmt using go/format package (not currently switched on)

check/gofmt.go

@@ -19,6 +19,7 @@ func (g GoFmt) Weight() float64 {
 // Percentage returns the percentage of .go files that pass gofmt
 func (g GoFmt) Percentage() (float64, []FileSummary, error) {
 	return GoTool(g.Dir, g.Filenames, []string{"gometalinter", "--deadline=180s", "--disable-all", "--enable=gofmt"})
+	// return GoFmtNative(g.Dir, g.Filenames)
 }
 
 // Description returns the description of gofmt

check/utils.go

@@ -2,7 +2,10 @@ package check
 
 import (
 	"bufio"
+	"bytes"
 	"fmt"
+	"go/format"
+	"io/ioutil"
 	"os"
 	"os/exec"
 	"path/filepath"
@@ -167,6 +170,26 @@ func (fs *FileSummary) AddError(out string) error {
 	return nil
 }
 
+func fileURL(dir, filename string) string {
+	var fileURL string
+	base := strings.TrimPrefix(dir, "repos/src/")
+	switch {
+	case strings.HasPrefix(base, "golang.org/x/"):
+		var pkg string
+		if len(strings.Split(base, "/")) >= 3 {
+			pkg = strings.Split(base, "/")[2]
+		}
+		return fmt.Sprintf("https://github.com/golang/%s/blob/master%s", pkg, strings.TrimPrefix(filename, "/"+base))
+	case strings.HasPrefix(base, "github.com/"):
+		if len(strings.Split(base, "/")) == 4 {
+			base = strings.Join(strings.Split(base, "/")[0:3], "/")
+		}
+		return fmt.Sprintf("https://%s/blob/master%s", base, strings.TrimPrefix(filename, "/"+base))
+	}
+
+	return fileURL
+}
+
 // GoTool runs a given go command (for example gofmt, go tool vet)
 // on a directory
 func GoTool(dir string, filenames, command []string) (float64, []FileSummary, error) {
@@ -206,21 +229,7 @@ outer:
 			continue outer
 		}
 
-		var fileURL string
-		base := strings.TrimPrefix(dir, "repos/src/")
-		switch {
-		case strings.HasPrefix(base, "golang.org/x/"):
-			var pkg string
-			if len(strings.Split(base, "/")) >= 3 {
-				pkg = strings.Split(base, "/")[2]
-			}
-			fileURL = fmt.Sprintf("https://github.com/golang/%s/blob/master%s", pkg, strings.TrimPrefix(filename, "/"+base))
-		case strings.HasPrefix(base, "github.com/"):
-			if len(strings.Split(base, "/")) == 4 {
-				base = strings.Join(strings.Split(base, "/")[0:3], "/")
-			}
-			fileURL = fmt.Sprintf("https://%s/blob/master%s", base, strings.TrimPrefix(filename, "/"+base))
-		}
+		fu := fileURL(dir, filename)
 		fs := fsMap[filename]
 		if fs.Filename == "" {
 			fs.Filename = filename
@@ -231,7 +240,7 @@ outer:
 				}
 
 			}
-			fs.FileURL = fileURL
+			fs.FileURL = fu
 		}
 		err = fs.AddError(out.Text())
 		if err != nil {
@@ -276,3 +285,45 @@ outer:
 
 	return float64(len(filenames)-len(failed)) / float64(len(filenames)), failed, nil
 }
+
+// GoFmtNative runs gofmt via golang's stdlib format pkg
+func GoFmtNative(dir string, filenames []string) (float64, []FileSummary, error) {
+	var failed = []FileSummary{}
+	for _, f := range filenames {
+		for _, skip := range skipSuffixes {
+			if strings.HasSuffix(f, skip) {
+				continue
+			}
+		}
+
+		if autoGenerated(f) {
+			continue
+		}
+
+		b, err := ioutil.ReadFile(f)
+		if err != nil {
+			return 0, []FileSummary{}, err
+		}
+		g, err := format.Source(b)
+		if err != nil {
+			return 0, []FileSummary{}, err
+		}
+		if !bytes.Equal(b, g) {
+			filename := strings.TrimPrefix(f, "repos/src")
+			fs := FileSummary{}
+			fs.Filename = filename
+			if strings.HasPrefix(filename, "/github.com") {
+				sp := strings.Split(filename, "/")
+				if len(sp) > 3 {
+					fs.Filename = strings.Join(sp[3:], "/")
+				}
+			}
+			fu := fileURL(dir, strings.TrimPrefix(f, "repos/src"))
+			fs.FileURL = fu
+			fs.Errors = append(fs.Errors, Error{1, "file is not gofmted"})
+			failed = append(failed, fs)
+		}
+	}
+
+	return float64(len(filenames)-len(failed)) / float64(len(filenames)), failed, nil
+}