[bugfix] Close reader gracefully when streaming recache of remote media to fileserver api caller (#1281)

* close pipereader on failed data function

* gently slurp the bytes

* readability updates

* go fmt

* tidy up file server tests + add more cases

* start moving io wrappers to separate iotools package. Remove use of buffering while piping recache stream

Signed-off-by: kim <grufwub@gmail.com>

* add license text

Signed-off-by: kim <grufwub@gmail.com>
Co-authored-by: kim <grufwub@gmail.com>

1 files changed, 121 insertions, 0 deletions

diff --git a/internal/iotools/io.go b/internal/iotools/io.go
new file mode 100644
index 000000000..d16a4ce9c
--- /dev/null
+++ b/internal/iotools/io.go
@@ -0,0 +1,121 @@
+/*
+   GoToSocial
+   Copyright (C) 2021-2022 GoToSocial Authors admin@gotosocial.org
+
+   This program is free software: you can redistribute it and/or modify
+   it under the terms of the GNU Affero General Public License as published by
+   the Free Software Foundation, either version 3 of the License, or
+   (at your option) any later version.
+
+   This program is distributed in the hope that it will be useful,
+   but WITHOUT ANY WARRANTY; without even the implied warranty of
+   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+   GNU Affero General Public License for more details.
+
+   You should have received a copy of the GNU Affero General Public License
+   along with this program.  If not, see <http://www.gnu.org/licenses/>.
+*/
+
+package iotools
+
+import (
+	"io"
+)
+
+// ReadFnCloser takes an io.Reader and wraps it to use the provided function to implement io.Closer.
+func ReadFnCloser(r io.Reader, close func() error) io.ReadCloser {
+	return &readFnCloser{
+		Reader: r,
+		close:  close,
+	}
+}
+
+type readFnCloser struct {
+	io.Reader
+	close func() error
+}
+
+func (r *readFnCloser) Close() error {
+	return r.close()
+}
+
+// WriteFnCloser takes an io.Writer and wraps it to use the provided function to implement io.Closer.
+func WriteFnCloser(w io.Writer, close func() error) io.WriteCloser {
+	return &writeFnCloser{
+		Writer: w,
+		close:  close,
+	}
+}
+
+type writeFnCloser struct {
+	io.Writer
+	close func() error
+}
+
+func (r *writeFnCloser) Close() error {
+	return r.close()
+}
+
+// SilentReader wraps an io.Reader to silence any
+// error output during reads. Instead they are stored
+// and accessible (not concurrency safe!) via .Error().
+type SilentReader struct {
+	io.Reader
+	err error
+}
+
+// SilenceReader wraps an io.Reader within SilentReader{}.
+func SilenceReader(r io.Reader) *SilentReader {
+	return &SilentReader{Reader: r}
+}
+
+func (r *SilentReader) Read(b []byte) (int, error) {
+	n, err := r.Reader.Read(b)
+	if err != nil {
+		// Store error for now
+		if r.err == nil {
+			r.err = err
+		}
+
+		// Pretend we're happy
+		// to continue reading.
+		n = len(b)
+	}
+	return n, nil
+}
+
+func (r *SilentReader) Error() error {
+	return r.err
+}
+
+// SilentWriter wraps an io.Writer to silence any
+// error output during writes. Instead they are stored
+// and accessible (not concurrency safe!) via .Error().
+type SilentWriter struct {
+	io.Writer
+	err error
+}
+
+// SilenceWriter wraps an io.Writer within SilentWriter{}.
+func SilenceWriter(w io.Writer) *SilentWriter {
+	return &SilentWriter{Writer: w}
+}
+
+func (w *SilentWriter) Write(b []byte) (int, error) {
+	n, err := w.Writer.Write(b)
+	if err != nil {
+		// Store error for now
+		if w.err == nil {
+			w.err = err
+		}
+
+		// Pretend we're happy
+		// to continue writing.
+		n = len(b)
+	}
+	return n, nil
+}
+
+func (w *SilentWriter) Error() error {
+	return w.err
+}