From 6b1dff54f991d5f420252d4186aac168893d854d Mon Sep 17 00:00:00 2001
From: Justin Hawkins <justin@hawkins.id.au>
Date: Mon, 18 Apr 2022 13:01:07 +0930
Subject: [PATCH] Remove some potential races

---
 main.go            | 12 +++++++-----
 version/version.go | 44 ++++++++++++++++++++++++++++++++------------
 2 files changed, 39 insertions(+), 17 deletions(-)

diff --git a/main.go b/main.go
index d2595ef..2eea312 100644
--- a/main.go
+++ b/main.go
@@ -23,7 +23,9 @@ var downloads download.Downloads
 var downloadId = 0
 var configService *config.ConfigService
 
-var versionInfo = version.Info{CurrentVersion: "v0.6.0"}
+var versionInfo = version.Manager{
+	VersionInfo: version.Info{CurrentVersion: "v0.6.0"},
+}
 
 //go:embed web
 var webFS embed.FS
@@ -39,7 +41,7 @@ type errorResponse struct {
 }
 
 func main() {
-	log.Printf("Starting gropple %s - https://github.com/tardisx/gropple", versionInfo.CurrentVersion)
+	log.Printf("Starting gropple %s - https://github.com/tardisx/gropple", versionInfo.GetInfo().CurrentVersion)
 
 	configService = &config.ConfigService{}
 	configService.DetermineConfigDir()
@@ -110,8 +112,8 @@ func main() {
 
 // versionRESTHandler returns the version information, if we have up-to-date info from github
 func versionRESTHandler(w http.ResponseWriter, r *http.Request) {
-	if versionInfo.GithubVersionFetched {
-		b, _ := json.Marshal(versionInfo)
+	if versionInfo.GetInfo().GithubVersionFetched {
+		b, _ := json.Marshal(versionInfo.GetInfo())
 		w.Write(b)
 	} else {
 		w.WriteHeader(400)
@@ -140,7 +142,7 @@ func homeHandler(w http.ResponseWriter, r *http.Request) {
 		Downloads:      downloads,
 		BookmarkletURL: template.URL(bookmarkletURL),
 		Config:         configService.Config,
-		Version:        versionInfo,
+		Version:        versionInfo.GetInfo(),
 	}
 
 	err = t.ExecuteTemplate(w, "layout", info)
diff --git a/version/version.go b/version/version.go
index 50876e5..c596c5f 100644
--- a/version/version.go
+++ b/version/version.go
@@ -8,6 +8,7 @@ import (
 	"io"
 	"log"
 	"net/http"
+	"sync"
 
 	"golang.org/x/mod/semver"
 )
@@ -19,8 +20,24 @@ type Info struct {
 	GithubVersionFetched bool   `json:"-"`
 }
 
-func (i *Info) UpdateGitHubVersion() error {
-	i.GithubVersionFetched = false
+type Manager struct {
+	VersionInfo Info
+	lock        sync.Mutex
+}
+
+func (m *Manager) GetInfo() Info {
+	// log.Print("getting info... b4 lock")
+	m.lock.Lock()
+	defer m.lock.Unlock()
+
+	return m.VersionInfo
+}
+
+func (m *Manager) UpdateGitHubVersion() error {
+	m.lock.Lock()
+	m.VersionInfo.GithubVersionFetched = false
+	m.lock.Unlock()
+
 	versionUrl := "https://api.github.com/repos/tardisx/gropple/releases"
 	resp, err := http.Get(versionUrl)
 	if err != nil {
@@ -51,27 +68,30 @@ func (i *Info) UpdateGitHubVersion() error {
 		return errors.New("no releases found")
 	}
 
-	i.GithubVersion = releases[0].Name
+	m.lock.Lock()
+
+	defer m.lock.Unlock()
+	m.VersionInfo.GithubVersion = releases[0].Name
+	m.VersionInfo.GithubVersionFetched = true
+	m.VersionInfo.UpgradeAvailable = m.canUpgrade()
 
-	i.GithubVersionFetched = true
-	i.UpgradeAvailable = i.canUpgrade()
 	return nil
 }
 
-func (i *Info) canUpgrade() bool {
-	if !i.GithubVersionFetched {
+func (m *Manager) canUpgrade() bool {
+	if !m.VersionInfo.GithubVersionFetched {
 		return false
 	}
 
-	if !semver.IsValid(i.CurrentVersion) {
-		log.Printf("current version %s is invalid", i.CurrentVersion)
+	if !semver.IsValid(m.VersionInfo.CurrentVersion) {
+		log.Printf("current version %s is invalid", m.VersionInfo.CurrentVersion)
 	}
 
-	if !semver.IsValid(i.GithubVersion) {
-		log.Printf("github version %s is invalid", i.GithubVersion)
+	if !semver.IsValid(m.VersionInfo.GithubVersion) {
+		log.Printf("github version %s is invalid", m.VersionInfo.GithubVersion)
 	}
 
-	if semver.Compare(i.CurrentVersion, i.GithubVersion) == -1 {
+	if semver.Compare(m.VersionInfo.CurrentVersion, m.VersionInfo.GithubVersion) == -1 {
 		return true
 	}
 	return false