From: Matt Joiner <anacrolix@gmail.com>
Date: Sat, 19 Jul 2025 11:41:18 +0000 (+1000)
Subject: Implement io.WriterTo for file storage pieces
X-Git-Tag: v1.59.0~8
X-Git-Url: http://www.git.stargrave.org/?a=commitdiff_plain;h=7e994d5ef3191428b130b7ad8f881e8e871d1dbb;p=btrtrc.git

Implement io.WriterTo for file storage pieces
---

diff --git a/storage/file-piece.go b/storage/file-piece.go
index f6c9de96..654ea155 100644
--- a/storage/file-piece.go
+++ b/storage/file-piece.go
@@ -27,6 +27,7 @@ type filePieceImpl struct {
 var _ interface {
 	PieceImpl
 	//PieceReaderer
+	io.WriterTo
 } = (*filePieceImpl)(nil)
 
 func (me *filePieceImpl) logger() *slog.Logger {
@@ -85,7 +86,7 @@ func (me *filePieceImpl) iterFileSegments() iter.Seq2[int, segments.Extent] {
 	}
 }
 
-// If a piece is complete, check consituent files have the minimum required sizes.
+// If a piece is complete, check constituent files have the minimum required sizes.
 func (me *filePieceImpl) checkCompleteFileSizes() (c Completion) {
 	c.Complete = true
 	c.Ok = true
@@ -315,6 +316,26 @@ func (me *filePieceImpl) partFiles() bool {
 	return me.t.partFiles()
 }
 
+func (me *filePieceImpl) WriteTo(w io.Writer) (n int64, err error) {
+	for fileIndex, extent := range me.iterFileSegments() {
+		file := me.t.file(fileIndex)
+		var f *os.File
+		f, err = me.t.openFile(file)
+		if err != nil {
+			return
+		}
+		f.Seek(extent.Start, io.SeekStart)
+		var n1 int64
+		n1, err = io.CopyN(w, f, extent.Length)
+		n += n1
+		f.Close()
+		if err != nil {
+			return
+		}
+	}
+	return
+}
+
 //
 //// TODO: Just implement StorageReader already.
 //func (me *filePieceImpl) NewReader() (PieceReader, error) {
diff --git a/storage/file-torrent-io.go b/storage/file-torrent-io.go
index 107f28e9..c2080b05 100644
--- a/storage/file-torrent-io.go
+++ b/storage/file-torrent-io.go
@@ -18,17 +18,7 @@ type fileTorrentImplIO struct {
 // Returns EOF on short or missing file.
 func (fst fileTorrentImplIO) readFileAt(file file, b []byte, off int64) (n int, err error) {
 	fst.fts.logger().Debug("readFileAt", "file.safeOsPath", file.safeOsPath)
-	var f sharedFileIf
-	file.mu.RLock()
-	// Fine to open once under each name on a unix system. We could make the shared file keys more
-	// constrained but it shouldn't matter. TODO: Ensure at most one of the names exist.
-	if fst.fts.partFiles() {
-		f, err = sharedFiles.Open(file.partFilePath())
-	}
-	if err == nil && f == nil || errors.Is(err, fs.ErrNotExist) {
-		f, err = sharedFiles.Open(file.safeOsPath)
-	}
-	file.mu.RUnlock()
+	f, err := fst.fts.openSharedFile(file)
 	if errors.Is(err, fs.ErrNotExist) {
 		// File missing is treated the same as a short file. Should we propagate this through the
 		// interface now that fs.ErrNotExist is a thing?
diff --git a/storage/file-torrent.go b/storage/file-torrent.go
index d3e458ab..55200d4f 100644
--- a/storage/file-torrent.go
+++ b/storage/file-torrent.go
@@ -125,3 +125,33 @@ func (fts *fileTorrentImpl) file(index int) file {
 		fileExtra: &fts.files[index],
 	}
 }
+
+// Open file for reading.
+func (me *fileTorrentImpl) openSharedFile(file file) (f sharedFileIf, err error) {
+	file.mu.RLock()
+	// Fine to open once under each name on a unix system. We could make the shared file keys more
+	// constrained, but it shouldn't matter. TODO: Ensure at most one of the names exist.
+	if me.partFiles() {
+		f, err = sharedFiles.Open(file.partFilePath())
+	}
+	if err == nil && f == nil || errors.Is(err, fs.ErrNotExist) {
+		f, err = sharedFiles.Open(file.safeOsPath)
+	}
+	file.mu.RUnlock()
+	return
+}
+
+// Open file for reading.
+func (me *fileTorrentImpl) openFile(file file) (f *os.File, err error) {
+	file.mu.RLock()
+	// Fine to open once under each name on a unix system. We could make the shared file keys more
+	// constrained, but it shouldn't matter. TODO: Ensure at most one of the names exist.
+	if me.partFiles() {
+		f, err = os.Open(file.partFilePath())
+	}
+	if err == nil && f == nil || errors.Is(err, fs.ErrNotExist) {
+		f, err = os.Open(file.safeOsPath)
+	}
+	file.mu.RUnlock()
+	return
+}
diff --git a/storage/iter.go b/storage/iter.go
index 9fe49c5e..b889dec1 100644
--- a/storage/iter.go
+++ b/storage/iter.go
@@ -1,17 +1,2 @@
 package storage
 
-import (
-	"iter"
-)
-
-func enumIter[T any](i iter.Seq[T]) iter.Seq2[int, T] {
-	return func(yield func(int, T) bool) {
-		j := 0
-		for t := range i {
-			if !yield(j, t) {
-				return
-			}
-			j++
-		}
-	}
-}