Make LazyFileReader use the Afero source fs

Fixes gohugoio#2317

hugolib/site.go

@@ -836,7 +836,7 @@ func (s *Site) reReadFile(absFilePath string) (*source.File, error) {
 	jww.INFO.Println("rereading", absFilePath)
 	var file *source.File
 
-	reader, err := source.NewLazyFileReader(absFilePath)
+	reader, err := source.NewLazyFileReader(hugofs.Source(), absFilePath)
 	if err != nil {
 		return nil, err
 	}

source/filesystem.go

@@ -14,13 +14,14 @@
 package source
 
 import (
-	"github.com/spf13/hugo/hugofs"
 	"io"
 	"os"
 	"path/filepath"
 	"regexp"
 	"strings"
 
+	"github.com/spf13/hugo/hugofs"
+
 	"github.com/spf13/viper"
 
 	"github.com/spf13/hugo/helpers"
@@ -84,7 +85,7 @@ func (f *Filesystem) captureFiles() {
 			return err
 		}
 		if b {
-			rd, err := NewLazyFileReader(filePath)
+			rd, err := NewLazyFileReader(hugofs.Source(), filePath)
 			if err != nil {
 				return err
 			}

source/lazy_file_reader.go

@@ -19,14 +19,15 @@ import (
 	"errors"
 	"fmt"
 	"io"
-	"io/ioutil"
-	"os"
+
+	"github.com/spf13/afero"
 )
 
 // LazyFileReader is an io.Reader implementation to postpone reading the file
 // contents until it is really needed. It keeps filename and file contents once
 // it is read.
 type LazyFileReader struct {
+	fs       afero.Fs
 	filename string
 	contents *bytes.Reader
 	pos      int64
@@ -35,13 +36,13 @@ type LazyFileReader struct {
 // NewLazyFileReader creates and initializes a new LazyFileReader of filename.
 // It checks whether the file can be opened. If it fails, it returns nil and an
 // error.
-func NewLazyFileReader(filename string) (*LazyFileReader, error) {
-	f, err := os.Open(filename)
+func NewLazyFileReader(fs afero.Fs, filename string) (*LazyFileReader, error) {
+	f, err := fs.Open(filename)
 	if err != nil {
 		return nil, err
 	}
 	defer f.Close()
-	return &LazyFileReader{filename: filename, contents: nil, pos: 0}, nil
+	return &LazyFileReader{fs: fs, filename: filename, contents: nil, pos: 0}, nil
 }
 
 // Filename returns a file name which LazyFileReader keeps
@@ -55,7 +56,7 @@ func (l *LazyFileReader) Filename() string {
 // the file.
 func (l *LazyFileReader) Read(p []byte) (n int, err error) {
 	if l.contents == nil {
-		b, err := ioutil.ReadFile(l.filename)
+		b, err := afero.ReadFile(l.fs, l.filename)
 		if err != nil {
 			return 0, fmt.Errorf("failed to read content from %s: %s", l.filename, err.Error())
 		}
@@ -80,7 +81,7 @@ func (l *LazyFileReader) Seek(offset int64, whence int) (pos int64, err error) {
 		case 1:
 			pos = l.pos + offset
 		case 2:
-			fi, err := os.Stat(l.filename)
+			fi, err := l.fs.Stat(l.filename)
 			if err != nil {
 				return 0, fmt.Errorf("failed to get %q info: %s", l.filename, err.Error())
 			}
@@ -115,7 +116,7 @@ func (l *LazyFileReader) WriteTo(w io.Writer) (n int64, err error) {
 		l.pos += n
 		return n, err
 	}
-	f, err := os.Open(l.filename)
+	f, err := l.fs.Open(l.filename)
 	if err != nil {
 		return 0, fmt.Errorf("failed to open %s to read content: %s", l.filename, err.Error())
 	}

source/lazy_file_reader_test.go

@@ -19,25 +19,29 @@ import (
 	"io/ioutil"
 	"os"
 	"testing"
+
+	"github.com/spf13/afero"
 )
 
 func TestNewLazyFileReader(t *testing.T) {
+	fs := afero.NewOsFs()
 	filename := "itdoesnotexistfile"
-	_, err := NewLazyFileReader(filename)
+	_, err := NewLazyFileReader(fs, filename)
 	if err == nil {
 		t.Errorf("NewLazyFileReader %s: error expected but no error is returned", filename)
 	}
 
 	filename = "lazy_file_reader_test.go"
-	_, err = NewLazyFileReader(filename)
+	_, err = NewLazyFileReader(fs, filename)
 	if err != nil {
 		t.Errorf("NewLazyFileReader %s: %v", filename, err)
 	}
 }
 
 func TestFilename(t *testing.T) {
+	fs := afero.NewOsFs()
 	filename := "lazy_file_reader_test.go"
-	rd, err := NewLazyFileReader(filename)
+	rd, err := NewLazyFileReader(fs, filename)
 	if err != nil {
 		t.Fatalf("NewLazyFileReader %s: %v", filename, err)
 	}
@@ -47,18 +51,19 @@ func TestFilename(t *testing.T) {
 }
 
 func TestRead(t *testing.T) {
+	fs := afero.NewOsFs()
 	filename := "lazy_file_reader_test.go"
-	fi, err := os.Stat(filename)
+	fi, err := fs.Stat(filename)
 	if err != nil {
 		t.Fatalf("os.Stat: %v", err)
 	}
 
-	b, err := ioutil.ReadFile(filename)
+	b, err := afero.ReadFile(fs, filename)
 	if err != nil {
 		t.Fatalf("ioutil.ReadFile: %v", err)
 	}
 
-	rd, err := NewLazyFileReader(filename)
+	rd, err := NewLazyFileReader(fs, filename)
 	if err != nil {
 		t.Fatalf("NewLazyFileReader %s: %v", filename, err)
 	}
@@ -92,9 +97,9 @@ func TestSeek(t *testing.T) {
 		moveto   int64
 		expected []byte
 	}
-
+	fs := afero.NewOsFs()
 	filename := "lazy_file_reader_test.go"
-	b, err := ioutil.ReadFile(filename)
+	b, err := afero.ReadFile(fs, filename)
 	if err != nil {
 		t.Fatalf("ioutil.ReadFile: %v", err)
 	}
@@ -108,7 +113,7 @@ func TestSeek(t *testing.T) {
 		{seek: 3, expected: nil},
 		{seek: os.SEEK_SET, offset: -1, expected: nil},
 	} {
-		rd, err := NewLazyFileReader(filename)
+		rd, err := NewLazyFileReader(fs, filename)
 		if err != nil {
 			t.Errorf("[%d] NewLazyFileReader %s: %v", i, filename, err)
 			continue
@@ -140,7 +145,7 @@ func TestSeek(t *testing.T) {
 	}
 
 	// cache case
-	rd, err := NewLazyFileReader(filename)
+	rd, err := NewLazyFileReader(fs, filename)
 	if err != nil {
 		t.Fatalf("NewLazyFileReader %s: %v", filename, err)
 	}
@@ -185,6 +190,7 @@ func TestSeek(t *testing.T) {
 }
 
 func TestWriteTo(t *testing.T) {
+	fs := afero.NewOsFs()
 	filename := "lazy_file_reader_test.go"
 	fi, err := os.Stat(filename)
 	if err != nil {
@@ -196,7 +202,7 @@ func TestWriteTo(t *testing.T) {
 		t.Fatalf("ioutil.ReadFile: %v", err)
 	}
 
-	rd, err := NewLazyFileReader(filename)
+	rd, err := NewLazyFileReader(fs, filename)
 	if err != nil {
 		t.Fatalf("NewLazyFileReader %s: %v", filename, err)
 	}