pkg/manager: remove a dependency on grep

Instead of calling grep (the implementations of which may differ in
different environments), traverse the directory and grep files with a
special pkg/osutil helper functionality.

2 files changed, 44 insertions, 0 deletions

diff --git a/pkg/osutil/fileutil.go b/pkg/osutil/fileutil.go
index cd5b602cf..01319bd5c 100644
--- a/pkg/osutil/fileutil.go
+++ b/pkg/osutil/fileutil.go
@@ -4,8 +4,10 @@
 package osutil
 
 import (
+	"bytes"
 	"fmt"
 	"io"
+	"io/fs"
 	"os"
 	"path/filepath"
 )
@@ -81,3 +83,28 @@ func WriteTempFile(data []byte) (string, error) {
 	f.Close()
 	return f.Name(), nil
 }
+
+// GrepFiles returns the list of files (relative to root) that include target.
+// If ext is not empty, the files will be filtered by the extension.
+// The function assumes that the files are not too big and may fit in memory.
+func GrepFiles(root, ext string, target []byte) ([]string, error) {
+	var ret []string
+	err := filepath.WalkDir(root, func(path string, d fs.DirEntry, err error) error {
+		if err != nil {
+			return err
+		}
+		if d.IsDir() || filepath.Ext(path) != ext {
+			return nil
+		}
+		content, err := os.ReadFile(path)
+		if err != nil {
+			return fmt.Errorf("failed to open %s: %w", path, err)
+		}
+		if bytes.Contains(content, target) {
+			rel, _ := filepath.Rel(root, path)
+			ret = append(ret, rel)
+		}
+		return nil
+	})
+	return ret, err
+}
diff --git a/pkg/osutil/fileutil_test.go b/pkg/osutil/fileutil_test.go
index 33a450fda..7609ca83b 100644
--- a/pkg/osutil/fileutil_test.go
+++ b/pkg/osutil/fileutil_test.go
@@ -9,6 +9,9 @@ import (
 	"strconv"
 	"sync"
 	"testing"
+
+	"github.com/stretchr/testify/assert"
+	"github.com/stretchr/testify/require"
 )
 
 func TestProcessTempDir(t *testing.T) {
@@ -60,3 +63,17 @@ func TestProcessTempDir(t *testing.T) {
 		}()
 	}
 }
+
+func TestGrepFiles(t *testing.T) {
+	dir := t.TempDir()
+	require.NoError(t, FillDirectory(dir, map[string]string{
+		"a.c":     `must be found`,
+		"a/b.c":   `nested`,
+		"a/b/c.c": `even more nested, must be found`,
+		"a.txt":   `must be found, but has a different extension`,
+	}))
+
+	ret, err := GrepFiles(dir, ".c", []byte(`must be found`))
+	require.NoError(t, err)
+	assert.ElementsMatch(t, []string{"a.c", "a/b/c.c"}, ret)
+}