From b28f498e75de30f8df81d8d590b186a6d5d6ca75 Mon Sep 17 00:00:00 2001
From: giwty <0b@LonXm#fkv>
Date: Mon, 5 Oct 2020 21:04:20 -0700
Subject: [PATCH] add file open retry

---
 go.mod                      |  1 +
 go.sum                      |  2 ++
 switchfs/splitFileReader.go | 50 +++++++++++++++++++++++++++++++++++--
 3 files changed, 51 insertions(+), 2 deletions(-)

diff --git a/go.mod b/go.mod
index 2a7f950..26f18c6 100644
--- a/go.mod
+++ b/go.mod
@@ -6,6 +6,7 @@ require (
 	github.com/asticode/go-astikit v0.8.0
 	github.com/asticode/go-astilectron v0.16.0
 	github.com/asticode/go-astilectron-bootstrap v0.4.1
+	github.com/avast/retry-go v2.6.1+incompatible
 	github.com/boltdb/bolt v1.3.1
 	github.com/go-openapi/strfmt v0.19.2 // indirect
 	github.com/jedib0t/go-pretty v4.3.0+incompatible
diff --git a/go.sum b/go.sum
index d1f0ebd..28fac46 100644
--- a/go.sum
+++ b/go.sum
@@ -15,6 +15,8 @@ github.com/asticode/go-astilectron-bundler v0.7.0 h1:P5Ot4loRUMSgHMEkH+DIQ0adKvE
 github.com/asticode/go-astilectron-bundler v0.7.0/go.mod h1:dHgXoS/SzrIcMIqzH9rhiWbZjUvjj4HNfUg+7sLeV1Q=
 github.com/asticode/go-bindata v1.0.0 h1:5whO0unjdx2kbAbzoBMS3307jKAEf3oQ1lJcx5RdgA8=
 github.com/asticode/go-bindata v1.0.0/go.mod h1:t/Y+/iCLrvaYkv8Y6PscRnyUeYzy9y9+8JC9CMcKdHY=
+github.com/avast/retry-go v2.6.1+incompatible h1:quvLI98pOPWtTq7xnbX4TI5l9PmRJooM2AI1T7mOFUA=
+github.com/avast/retry-go v2.6.1+incompatible/go.mod h1:XtSnn+n/sHqQIpZ10K1qAevBhOOCWBLXXy3hyiqqBrY=
 github.com/boltdb/bolt v1.3.1 h1:JQmyP4ZBrce+ZQu0dY660FMfatumYDLun9hBCUVIkF4=
 github.com/boltdb/bolt v1.3.1/go.mod h1:clJnj/oiGkjum5o1McbSZDSLxVThjynRyGBgiAx27Ps=
 github.com/davecgh/go-spew v1.1.0/go.mod h1:J7Y8YcW2NihsgmVo/mv3lAwl/skON4iLHjSsI+c5H38=
diff --git a/switchfs/splitFileReader.go b/switchfs/splitFileReader.go
index e4b8f43..8cdc864 100644
--- a/switchfs/splitFileReader.go
+++ b/switchfs/splitFileReader.go
@@ -2,6 +2,7 @@ package switchfs
 
 import (
 	"errors"
+	"github.com/avast/retry-go"
 	"io"
 	"io/ioutil"
 	"os"
@@ -22,6 +23,38 @@ type splitFile struct {
 	chunkSize int64
 }
 
+type fileWrapper struct {
+	file ReadAtCloser
+	path string
+}
+
+func NewFileWrapper(filePath string) (*fileWrapper, error) {
+	result := fileWrapper{}
+	result.path = filePath
+	file, err := _openFile(filePath)
+	if err != nil {
+		return nil, err
+	}
+	result.file = file
+	return &result, nil
+}
+
+func (sp *fileWrapper) ReadAt(p []byte, off int64) (n int, err error) {
+	if sp.file != nil {
+		return sp.file.ReadAt(p, off)
+	}
+	return 0, errors.New("file is not opened")
+}
+
+func (sp *fileWrapper) Close() error {
+
+	if sp.file != nil {
+		return sp.file.Close()
+	}
+
+	return nil
+}
+
 func NewSplitFileReader(filePath string) (*splitFile, error) {
 	result := splitFile{}
 	index := strings.LastIndex(filePath, string(os.PathSeparator))
@@ -51,7 +84,7 @@ func (sp *splitFile) ReadAt(p []byte, off int64) (n int, err error) {
 	}
 
 	if len(sp.files) == 0 || sp.files[part] == nil {
-		file, _ := os.Open(path.Join(sp.path, sp.info[part].Name()))
+		file, _ := _openFile(path.Join(sp.path, sp.info[part].Name()))
 		sp.files[part] = file
 	}
 	off = off - sp.chunkSize*int64(part)
@@ -62,6 +95,19 @@ func (sp *splitFile) ReadAt(p []byte, off int64) (n int, err error) {
 	return sp.files[part].ReadAt(p, off)
 }
 
+func _openFile(path string) (*os.File, error) {
+	var file *os.File
+	var err error
+	retry.Attempts(5)
+	err = retry.Do(
+		func() error {
+			file, err = os.Open(path)
+			return err
+		},
+	)
+	return file, err
+}
+
 func (sp *splitFile) Close() error {
 	for _, file := range sp.files {
 		if file != nil {
@@ -76,6 +122,6 @@ func OpenFile(filePath string) (ReadAtCloser, error) {
 	if _, err := strconv.Atoi(filePath[len(filePath)-1:]); err == nil {
 		return NewSplitFileReader(filePath)
 	} else {
-		return os.Open(filePath)
+		return NewFileWrapper(filePath)
 	}
 }