context fs

pkg/ctxio/reader.go

@@ -0,0 +1,48 @@
+package ctxio
+
+import (
+	"context"
+	"io"
+)
+
+type ReaderAtCloser interface {
+	ReaderAt
+	Closer
+}
+
+type ReaderAt interface {
+	ReadAt(ctx context.Context, p []byte, off int64) (n int, err error)
+}
+
+type Reader interface {
+	Read(ctx context.Context, p []byte) (n int, err error)
+}
+
+type Closer interface {
+	Close(ctx context.Context) error
+}
+type contextReader struct {
+	ctx context.Context
+	r   Reader
+}
+
+func (r *contextReader) Read(p []byte) (n int, err error) {
+	return r.r.Read(r.ctx, p)
+}
+
+func IoReaderAt(ctx context.Context, r ReaderAt) io.ReaderAt {
+	return &contextReaderAt{ctx: ctx, r: r}
+}
+
+type contextReaderAt struct {
+	ctx context.Context
+	r   ReaderAt
+}
+
+func (c *contextReaderAt) ReadAt(p []byte, off int64) (n int, err error) {
+	return c.r.ReadAt(c.ctx, p, off)
+}
+
+func IoReader(ctx context.Context, r Reader) io.Reader {
+	return &contextReader{ctx: ctx, r: r}
+}

pkg/ctxio/seeker.go

@@ -0,0 +1,102 @@
+package ctxio
+
+import (
+	"context"
+	"io"
+	"sync"
+)
+
+type ioSeekerWrapper struct {
+	ctx context.Context
+
+	mu   sync.Mutex
+	pos  int64
+	size int64
+
+	r ReaderAt
+}
+
+func IoReadSeekerWrapper(ctx context.Context, r ReaderAt, size int64) io.ReadSeeker {
+	return &ioSeekerWrapper{
+		ctx:  ctx,
+		r:    r,
+		size: size,
+	}
+}
+
+func (r *ioSeekerWrapper) Seek(offset int64, whence int) (int64, error) {
+	r.mu.Lock()
+	defer r.mu.Unlock()
+
+	switch whence {
+	case io.SeekStart:
+		r.pos = offset
+	case io.SeekCurrent:
+		r.pos = r.pos + offset
+	case io.SeekEnd:
+		r.pos = r.size + offset
+	}
+
+	return r.pos, nil
+}
+
+func (r *ioSeekerWrapper) Read(p []byte) (int, error) {
+	r.mu.Lock()
+	defer r.mu.Unlock()
+
+	n, err := r.r.ReadAt(r.ctx, p, r.pos)
+	r.pos += int64(n)
+
+	return n, err
+}
+
+var _ io.ReadSeekCloser = (*ioSeekerCloserWrapper)(nil)
+
+type ioSeekerCloserWrapper struct {
+	ctx context.Context
+
+	mu   sync.Mutex
+	pos  int64
+	size int64
+
+	r ReaderAtCloser
+}
+
+func IoReadSeekCloserWrapper(ctx context.Context, r ReaderAtCloser, size int64) io.ReadSeekCloser {
+	return &ioSeekerCloserWrapper{
+		ctx:  ctx,
+		r:    r,
+		size: size,
+	}
+}
+
+func (r *ioSeekerCloserWrapper) Seek(offset int64, whence int) (int64, error) {
+	r.mu.Lock()
+	defer r.mu.Unlock()
+
+	switch whence {
+	case io.SeekStart:
+		r.pos = offset
+	case io.SeekCurrent:
+		r.pos = r.pos + offset
+	case io.SeekEnd:
+		r.pos = r.size + offset
+	}
+
+	return r.pos, nil
+}
+
+func (r *ioSeekerCloserWrapper) Read(p []byte) (int, error) {
+	r.mu.Lock()
+	defer r.mu.Unlock()
+
+	n, err := r.r.ReadAt(r.ctx, p, r.pos)
+	r.pos += int64(n)
+
+	return n, err
+}
+
+// Close implements io.ReadSeekCloser.
+func (r *ioSeekerCloserWrapper) Close() error {
+	return r.r.Close(r.ctx)
+}