package vfsgen
import (
"bytes"
"compress/gzip"
"errors"
"fmt"
"io"
"io/ioutil"
"net/http"
"os"
pathpkg "path"
"sort"
"strconv"
"text/template"
"time"
"github.com/shurcooL/httpfs/vfsutil"
)
// Generate Go code that statically implements input filesystem,
// write the output to a file specified in opt.
func Generate(input http.FileSystem, opt Options) error {
opt.fillMissing()
// Use an in-memory buffer to generate the entire output.
buf := new(bytes.Buffer)
err := t.ExecuteTemplate(buf, "Header", opt)
if err != nil {
return err
}
var toc toc
err = findAndWriteFiles(buf, input, &toc)
if err != nil {
return err
}
err = t.ExecuteTemplate(buf, "DirEntries", toc.dirs)
if err != nil {
return err
}
err = t.ExecuteTemplate(buf, "Trailer", toc)
if err != nil {
return err
}
// Write output file (all at once).
fmt.Println("writing", opt.Filename)
err = ioutil.WriteFile(opt.Filename, buf.Bytes(), 0644)
return err
}
type toc struct {
dirs []*dirInfo
HasCompressedFile bool // There's at least one compressedFile.
HasFile bool // There's at least one uncompressed file.
}
// fileInfo is a definition of a file.
type fileInfo struct {
Path string
Name string
ModTime time.Time
UncompressedSize int64
}
// dirInfo is a definition of a directory.
type dirInfo struct {
Path string
Name string
ModTime time.Time
Entries []string
}
// findAndWriteFiles recursively finds all the file paths in the given directory tree.
// They are added to the given map as keys. Values will be safe function names
// for each file, which will be used when generating the output code.
func findAndWriteFiles(buf *bytes.Buffer, fs http.FileSystem, toc *toc) error {
walkFn := func(path string, fi os.FileInfo, r io.ReadSeeker, err error) error {
if err != nil {
// Consider all errors reading the input filesystem as fatal.
return err
}
switch fi.IsDir() {
case false:
file := &fileInfo{
Path: path,
Name: pathpkg.Base(path),
ModTime: fi.ModTime().UTC(),
UncompressedSize: fi.Size(),
}
marker := buf.Len()
// Write CompressedFileInfo.
err = writeCompressedFileInfo(buf, file, r)
switch err {
default:
return err
case nil:
toc.HasCompressedFile = true
// If compressed file is not smaller than original, revert and write original file.
case errCompressedNotSmaller:
_, err = r.Seek(0, io.SeekStart)
if err != nil {
return err
}
buf.Truncate(marker)
// Write FileInfo.
err = writeFileInfo(buf, file, r)
if err != nil {
return err
}
toc.HasFile = true
}
case true:
entries, err := readDirPaths(fs, path)
if err != nil {
return err
}
dir := &dirInfo{
Path: path,
Name: pathpkg.Base(path),
ModTime: fi.ModTime().UTC(),
Entries: entries,
}
toc.dirs = append(toc.dirs, dir)
// Write DirInfo.
err = t.ExecuteTemplate(buf, "DirInfo", dir)
if err != nil {
return err
}
}
return nil
}
err := vfsutil.WalkFiles(fs, "/", walkFn)
return err
}
// readDirPaths reads the directory named by dirname and returns
// a sorted list of directory paths.
func readDirPaths(fs http.FileSystem, dirname string) ([]string, error) {
fis, err := vfsutil.ReadDir(fs, dirname)
if err != nil {
return nil, err
}
paths := make([]string, len(fis))
for i := range fis {
paths[i] = pathpkg.Join(dirname, fis[i].Name())
}
sort.Strings(paths)
return paths, nil
}
// writeCompressedFileInfo writes CompressedFileInfo.
// It returns errCompressedNotSmaller if compressed file is not smaller than original.
func writeCompressedFileInfo(w io.Writer, file *fileInfo, r io.Reader) error {
err := t.ExecuteTemplate(w, "CompressedFileInfo-Before", file)
if err != nil {
return err
}
sw := &stringWriter{Writer: w}
gw := gzip.NewWriter(sw)
_, err = io.Copy(gw, r)
if err != nil {
return err
}
err = gw.Close()
if err != nil {
return err
}
if sw.N >= file.UncompressedSize {
return errCompressedNotSmaller
}
err = t.ExecuteTemplate(w, "CompressedFileInfo-After", file)
return err
}
var errCompressedNotSmaller = errors.New("compressed file is not smaller than original")
// Write FileInfo.
func writeFileInfo(w io.Writer, file *fileInfo, r io.Reader) error {
err := t.ExecuteTemplate(w, "FileInfo-Before", file)
if err != nil {
return err
}
sw := &stringWriter{Writer: w}
_, err = io.Copy(sw, r)
if err != nil {
return err
}
err = t.ExecuteTemplate(w, "FileInfo-After", file)
return err
}
var t = template.Must(template.New("").Funcs(template.FuncMap{
"quote": strconv.Quote,
"comment": func(s string) (string, error) {
var buf bytes.Buffer
cw := &commentWriter{W: &buf}
_, err := io.WriteString(cw, s)
if err != nil {
return "", err
}
err = cw.Close()
return buf.String(), err
},
}).Parse(`{{define "Header"}}// Code generated by vfsgen; DO NOT EDIT.
{{with .BuildTags}}// +build {{.}}
{{end}}package {{.PackageName}}
import (
"bytes"
"compress/gzip"
"fmt"
"io"
"io/ioutil"
"net/http"
"os"
pathpkg "path"
"time"
)
{{comment .VariableComment}}
var {{.VariableName}} = func() http.FileSystem {
fs := vfsgen۰FS{
{{end}}
{{define "CompressedFileInfo-Before"}} {{quote .Path}}: &vfsgen۰CompressedFileInfo{
name: {{quote .Name}},
modTime: {{template "Time" .ModTime}},
uncompressedSize: {{.UncompressedSize}},
{{/* This blank line separating compressedContent is neccessary to prevent potential gofmt issues. See issue #19. */}}
compressedContent: []byte("{{end}}{{define "CompressedFileInfo-After"}}"),
},
{{end}}
{{define "FileInfo-Before"}} {{quote .Path}}: &vfsgen۰FileInfo{
name: {{quote .Name}},
modTime: {{template "Time" .ModTime}},
content: []byte("{{end}}{{define "FileInfo-After"}}"),
},
{{end}}
{{define "DirInfo"}} {{quote .Path}}: &vfsgen۰DirInfo{
name: {{quote .Name}},
modTime: {{template "Time" .ModTime}},
},
{{end}}
{{define "DirEntries"}} }
{{range .}}{{if .Entries}} fs[{{quote .Path}}].(*vfsgen۰DirInfo).entries = []os.FileInfo{{"{"}}{{range .Entries}}
fs[{{quote .}}].(os.FileInfo),{{end}}
}
{{end}}{{end}}
return fs
}()
{{end}}
{{define "Trailer"}}
type vfsgen۰FS map[string]interface{}
func (fs vfsgen۰FS) Open(path string) (http.File, error) {
path = pathpkg.Clean("/" + path)
f, ok := fs[path]
if !ok {
return nil, &os.PathError{Op: "open", Path: path, Err: os.ErrNotExist}
}
switch f := f.(type) {{"{"}}{{if .HasCompressedFile}}
case *vfsgen۰CompressedFileInfo:
gr, err := gzip.NewReader(bytes.NewReader(f.compressedContent))
if err != nil {
// This should never happen because we generate the gzip bytes such that they are always valid.
panic("unexpected error reading own gzip compressed bytes: " + err.Error())
}
return &vfsgen۰CompressedFile{
vfsgen۰CompressedFileInfo: f,
gr: gr,
}, nil{{end}}{{if .HasFile}}
case *vfsgen۰FileInfo:
return &vfsgen۰File{
vfsgen۰FileInfo: f,
Reader: bytes.NewReader(f.content),
}, nil{{end}}
case *vfsgen۰DirInfo:
return &vfsgen۰Dir{
vfsgen۰DirInfo: f,
}, nil
default:
// This should never happen because we generate only the above types.
panic(fmt.Sprintf("unexpected type %T", f))
}
}
{{if .HasCompressedFile}}
// vfsgen۰CompressedFileInfo is a static definition of a gzip compressed file.
type vfsgen۰CompressedFileInfo struct {
name string
modTime time.Time
compressedContent []byte
uncompressedSize int64
}
func (f *vfsgen۰CompressedFileInfo) Readdir(count int) ([]os.FileInfo, error) {
return nil, fmt.Errorf("cannot Readdir from file %s", f.name)
}
func (f *vfsgen۰CompressedFileInfo) Stat() (os.FileInfo, error) { return f, nil }
func (f *vfsgen۰CompressedFileInfo) GzipBytes() []byte {
return f.compressedContent
}
func (f *vfsgen۰CompressedFileInfo) Name() string { return f.name }
func (f *vfsgen۰CompressedFileInfo) Size() int64 { return f.uncompressedSize }
func (f *vfsgen۰CompressedFileInfo) Mode() os.FileMode { return 0444 }
func (f *vfsgen۰CompressedFileInfo) ModTime() time.Time { return f.modTime }
func (f *vfsgen۰CompressedFileInfo) IsDir() bool { return false }
func (f *vfsgen۰CompressedFileInfo) Sys() interface{} { return nil }
// vfsgen۰CompressedFile is an opened compressedFile instance.
type vfsgen۰CompressedFile struct {
*vfsgen۰CompressedFileInfo
gr *gzip.Reader
grPos int64 // Actual gr uncompressed position.
seekPos int64 // Seek uncompressed position.
}
func (f *vfsgen۰CompressedFile) Read(p []byte) (n int, err error) {
if f.grPos > f.seekPos {
// Rewind to beginning.
err = f.gr.Reset(bytes.NewReader(f.compressedContent))
if err != nil {
return 0, err
}
f.grPos = 0
}
if f.grPos < f.seekPos {
// Fast-forward.
_, err = io.CopyN(ioutil.Discard, f.gr, f.seekPos-f.grPos)
if err != nil {
return 0, err
}
f.grPos = f.seekPos
}
n, err = f.gr.Read(p)
f.grPos += int64(n)
f.seekPos = f.grPos
return n, err
}
func (f *vfsgen۰CompressedFile) Seek(offset int64, whence int) (int64, error) {
switch whence {
case io.SeekStart:
f.seekPos = 0 + offset
case io.SeekCurrent:
f.seekPos += offset
case io.SeekEnd:
f.seekPos = f.uncompressedSize + offset
default:
panic(fmt.Errorf("invalid whence value: %v", whence))
}
return f.seekPos, nil
}
func (f *vfsgen۰CompressedFile) Close() error {
return f.gr.Close()
}
{{else}}
// We already imported "compress/gzip" and "io/ioutil", but ended up not using them. Avoid unused import error.
var _ = gzip.Reader{}
var _ = ioutil.Discard
{{end}}{{if .HasFile}}
// vfsgen۰FileInfo is a static definition of an uncompressed file (because it's not worth gzip compressing).
type vfsgen۰FileInfo struct {
name string
modTime time.Time
content []byte
}
func (f *vfsgen۰FileInfo) Readdir(count int) ([]os.FileInfo, error) {
return nil, fmt.Errorf("cannot Readdir from file %s", f.name)
}
func (f *vfsgen۰FileInfo) Stat() (os.FileInfo, error) { return f, nil }
func (f *vfsgen۰FileInfo) NotWorthGzipCompressing() {}
func (f *vfsgen۰FileInfo) Name() string { return f.name }
func (f *vfsgen۰FileInfo) Size() int64 { return int64(len(f.content)) }
func (f *vfsgen۰FileInfo) Mode() os.FileMode { return 0444 }
func (f *vfsgen۰FileInfo) ModTime() time.Time { return f.modTime }
func (f *vfsgen۰FileInfo) IsDir() bool { return false }
func (f *vfsgen۰FileInfo) Sys() interface{} { return nil }
// vfsgen۰File is an opened file instance.
type vfsgen۰File struct {
*vfsgen۰FileInfo
*bytes.Reader
}
func (f *vfsgen۰File) Close() error {
return nil
}
{{else if not .HasCompressedFile}}
// We already imported "bytes", but ended up not using it. Avoid unused import error.
var _ = bytes.Reader{}
{{end}}
// vfsgen۰DirInfo is a static definition of a directory.
type vfsgen۰DirInfo struct {
name string
modTime time.Time
entries []os.FileInfo
}
func (d *vfsgen۰DirInfo) Read([]byte) (int, error) {
return 0, fmt.Errorf("cannot Read from directory %s", d.name)
}
func (d *vfsgen۰DirInfo) Close() error { return nil }
func (d *vfsgen۰DirInfo) Stat() (os.FileInfo, error) { return d, nil }
func (d *vfsgen۰DirInfo) Name() string { return d.name }
func (d *vfsgen۰DirInfo) Size() int64 { return 0 }
func (d *vfsgen۰DirInfo) Mode() os.FileMode { return 0755 | os.ModeDir }
func (d *vfsgen۰DirInfo) ModTime() time.Time { return d.modTime }
func (d *vfsgen۰DirInfo) IsDir() bool { return true }
func (d *vfsgen۰DirInfo) Sys() interface{} { return nil }
// vfsgen۰Dir is an opened dir instance.
type vfsgen۰Dir struct {
*vfsgen۰DirInfo
pos int // Position within entries for Seek and Readdir.
}
func (d *vfsgen۰Dir) Seek(offset int64, whence int) (int64, error) {
if offset == 0 && whence == io.SeekStart {
d.pos = 0
return 0, nil
}
return 0, fmt.Errorf("unsupported Seek in directory %s", d.name)
}
func (d *vfsgen۰Dir) Readdir(count int) ([]os.FileInfo, error) {
if d.pos >= len(d.entries) && count > 0 {
return nil, io.EOF
}
if count <= 0 || count > len(d.entries)-d.pos {
count = len(d.entries) - d.pos
}
e := d.entries[d.pos : d.pos+count]
d.pos += count
return e, nil
}
{{end}}
{{define "Time"}}
{{- if .IsZero -}}
time.Time{}
{{- else -}}
time.Date({{.Year}}, {{printf "%d" .Month}}, {{.Day}}, {{.Hour}}, {{.Minute}}, {{.Second}}, {{.Nanosecond}}, time.UTC)
{{- end -}}
{{end}}
`))
