history: add UI view to traces

Signed-off-by: Tonis Tiigi <tonistiigi@gmail.com>

vendor/github.com/tonistiigi/jaeger-ui-rest/decompress/decompress.go

@@ -0,0 +1,117 @@
+package decompress
+
+import (
+	"bytes"
+	"compress/gzip"
+	"io"
+	"io/fs"
+	"path/filepath"
+	"sync"
+)
+
+type decompressFS struct {
+	fs.FS
+	mu     sync.Mutex
+	data   map[string][]byte
+	inject Injector
+}
+
+type Injector interface {
+	Inject(name string, dt []byte) ([]byte, bool)
+}
+
+func NewFS(fsys fs.FS, injector Injector) fs.FS {
+	return &decompressFS{
+		FS:     fsys,
+		data:   make(map[string][]byte),
+		inject: injector,
+	}
+}
+
+func (d *decompressFS) Open(name string) (fs.File, error) {
+	name = filepath.Clean(name)
+
+	f, err := d.FS.Open(name)
+	if err != nil {
+		return nil, err
+	}
+
+	d.mu.Lock()
+	defer d.mu.Unlock()
+
+	dt, ok := d.data[name]
+	if ok {
+		return &staticFile{
+			Reader: bytes.NewReader(dt),
+			f:      f,
+		}, nil
+	}
+
+	fi, err := f.Stat()
+	if err != nil {
+		f.Close()
+		return nil, err
+	}
+
+	if fi.IsDir() {
+		return f, nil
+	}
+
+	gzReader, err := gzip.NewReader(f)
+	if err != nil {
+		f.Close()
+		return nil, err
+	}
+
+	buf := &bytes.Buffer{}
+	if _, err := io.Copy(buf, gzReader); err != nil {
+		f.Close()
+		return nil, err
+	}
+
+	dt = buf.Bytes()
+	if d.inject != nil {
+		newdt, ok := d.inject.Inject(name, dt)
+		if ok {
+			dt = newdt
+		}
+	}
+
+	d.data[name] = dt
+
+	return &staticFile{
+		Reader: bytes.NewReader(dt),
+		f:      f,
+	}, nil
+}
+
+type staticFile struct {
+	*bytes.Reader
+	f fs.File
+}
+
+func (s *staticFile) Stat() (fs.FileInfo, error) {
+	fi, err := s.f.Stat()
+	if err != nil {
+		return nil, err
+	}
+	return &fileInfo{
+		FileInfo: fi,
+		size:     int64(s.Len()),
+	}, nil
+}
+
+func (s *staticFile) Close() error {
+	return s.f.Close()
+}
+
+type fileInfo struct {
+	fs.FileInfo
+	size int64
+}
+
+func (f *fileInfo) Size() int64 {
+	return f.size
+}
+
+var _ fs.File = &staticFile{}