feat: Add basic STFS-backed Read implementation

internal/fs/file.go

@@ -1,18 +1,25 @@
 package fs
 
 import (
+	"bytes"
+	"io"
+	"io/fs"
 	"log"
 	"os"
+	"sync"
 
 	models "github.com/pojntfx/stfs/internal/db/sqlite/models/metadata"
 	"github.com/pojntfx/stfs/pkg/config"
 	"github.com/pojntfx/stfs/pkg/inventory"
+	"github.com/pojntfx/stfs/pkg/operations"
 	"github.com/spf13/afero"
 )
 
 type File struct {
 	afero.File
 
+	ops *operations.Operations
+
 	metadata config.MetadataConfig
 
 	path string
@@ -20,10 +27,15 @@ type File struct {
 	name string
 	info os.FileInfo
 
+	reader     *io.PipeReader
+	readerLock sync.Mutex
+
 	onHeader func(hdr *models.Header)
 }
 
 func NewFile(
+	ops *operations.Operations,
+
 	metadata config.MetadataConfig,
 
 	path string,
@@ -34,6 +46,8 @@ func NewFile(
 	onHeader func(hdr *models.Header),
 ) *File {
 	return &File{
+		ops: ops,
+
 		metadata: metadata,
 
 		path: path,
@@ -45,19 +59,19 @@ func NewFile(
 	}
 }
 
-func (f File) Name() string {
+func (f *File) Name() string {
 	log.Println("File.Name", f.name)
 
 	return f.name
 }
 
-func (f File) Stat() (os.FileInfo, error) {
+func (f *File) Stat() (os.FileInfo, error) {
 	log.Println("File.Stat", f.name)
 
 	return f.info, nil
 }
 
-func (f File) Readdir(count int) ([]os.FileInfo, error) {
+func (f *File) Readdir(count int) ([]os.FileInfo, error) {
 	log.Println("File.Readdir", f.name, count)
 
 	hdrs, err := inventory.List(
@@ -80,61 +94,94 @@ func (f File) Readdir(count int) ([]os.FileInfo, error) {
 	return fileInfos, nil
 }
 
-func (f File) Readdirnames(n int) ([]string, error) {
+func (f *File) Readdirnames(n int) ([]string, error) {
 	log.Println("File.Readdirnames", f.name, n)
 
 	return nil, ErrNotImplemented
 }
 
-func (f File) Sync() error {
+func (f *File) Sync() error {
 	log.Println("File.Sync", f.name)
 
 	return ErrNotImplemented
 }
 
-func (f File) Truncate(size int64) error {
+func (f *File) Truncate(size int64) error {
 	log.Println("File.Truncate", f.name, size)
 
 	return ErrNotImplemented
 }
 
-func (f File) WriteString(s string) (ret int, err error) {
+func (f *File) WriteString(s string) (ret int, err error) {
 	log.Println("File.WriteString", f.name, s)
 
 	return -1, ErrNotImplemented
 }
 
-func (f File) Close() error {
+func (f *File) Close() error {
 	log.Println("File.Close", f.name)
 
 	return ErrNotImplemented
 }
 
-func (f File) Read(p []byte) (n int, err error) {
-	log.Println("File.Read", f.name, p)
+func (f *File) Read(p []byte) (n int, err error) {
+	log.Println("File.Read", f.name, len(p))
 
-	return -1, ErrNotImplemented
+	f.readerLock.Lock()
+	defer f.readerLock.Unlock()
+
+	if f.reader == nil {
+		reader, writer := io.Pipe()
+
+		go func() {
+			if err := f.ops.Restore(
+				func(path string, mode fs.FileMode) (io.WriteCloser, error) {
+					return writer, nil
+				},
+				func(path string, mode fs.FileMode) error {
+					// Not necessary; can't read on a directory
+					return nil
+				},
+
+				f.path,
+				"",
+				true,
+			); err != nil {
+				// TODO: Handle error
+				panic(err)
+			}
+		}()
+
+		f.reader = reader
+	}
+
+	w := &bytes.Buffer{}
+	if _, err := io.CopyN(w, f.reader, int64(len(p))); err != nil {
+		return -1, err
+	}
+
+	return copy(p, w.Bytes()), nil
 }
 
-func (f File) ReadAt(p []byte, off int64) (n int, err error) {
+func (f *File) ReadAt(p []byte, off int64) (n int, err error) {
 	log.Println("File.ReadAt", f.name, p, off)
 
 	return -1, ErrNotImplemented
 }
 
-func (f File) Seek(offset int64, whence int) (int64, error) {
+func (f *File) Seek(offset int64, whence int) (int64, error) {
 	log.Println("File.Seek", f.name, offset, whence)
 
 	return -1, ErrNotImplemented
 }
 
-func (f File) Write(p []byte) (n int, err error) {
+func (f *File) Write(p []byte) (n int, err error) {
 	log.Println("File.Write", f.name, p)
 
 	return -1, ErrNotImplemented
 }
 
-func (f File) WriteAt(p []byte, off int64) (n int, err error) {
+func (f *File) WriteAt(p []byte, off int64) (n int, err error) {
 	log.Println("File.WriteAt", f.name, p, off)
 
 	return -1, ErrNotImplemented

internal/fs/fileinfo.go

@@ -28,37 +28,37 @@ func NewFileInfo(hdr *tar.Header) *FileInfo {
 	}
 }
 
-func (f FileInfo) Name() string {
+func (f *FileInfo) Name() string {
 	log.Println("FileInfo.Name", f.name)
 
 	return f.name
 }
 
-func (f FileInfo) Size() int64 {
+func (f *FileInfo) Size() int64 {
 	log.Println("FileInfo.Size", f.name)
 
 	return f.size
 }
 
-func (f FileInfo) Mode() os.FileMode {
+func (f *FileInfo) Mode() os.FileMode {
 	log.Println("FileInfo.Mode", f.name)
 
 	return os.FileMode(f.mode)
 }
 
-func (f FileInfo) ModTime() time.Time {
+func (f *FileInfo) ModTime() time.Time {
 	log.Println("FileInfo.ModTime", f.name)
 
 	return f.modTime
 }
 
-func (f FileInfo) IsDir() bool {
+func (f *FileInfo) IsDir() bool {
 	log.Println("FileInfo.IsDir", f.name)
 
 	return f.isDir
 }
 
-func (f FileInfo) Sys() interface{} {
+func (f *FileInfo) Sys() interface{} {
 	log.Println("FileInfo.Sys", f.name)
 
 	return nil

internal/fs/filesystem.go

@@ -86,6 +86,8 @@ func (f *FileSystem) Open(name string) (afero.File, error) {
 	}
 
 	return NewFile(
+		f.ops,
+
 		f.metadata,
 
 		hdr.Name,