From 81b0da8156e9c8fed78c34b9661f1fe9c5295514 Mon Sep 17 00:00:00 2001
From: Nathaniel Cook <nvcook42@gmail.com>
Date: Thu, 18 Aug 2016 09:01:12 -0600
Subject: [PATCH] recover from panic on startup and retry

---
 bench.txt      |  9 ---------
 cmd/avi/avi.go | 10 ++++++++--
 head/head.go   | 21 ++++++++++++++++++++-
 3 files changed, 28 insertions(+), 12 deletions(-)
 delete mode 100644 bench.txt

diff --git a/bench.txt b/bench.txt
deleted file mode 100644
index 4c38c42..0000000
--- a/bench.txt
+++ /dev/null
@@ -1,9 +0,0 @@
-PASS
-BenchmarkLoop	 2000000	       913 ns/op
-ok  	github.com/nathanielc/avi	2.759s
-?   	github.com/nathanielc/avi/avi	[no test files]
-?   	github.com/nathanielc/avi/head	[no test files]
-?   	github.com/nathanielc/avi/jac	[no test files]
-?   	github.com/nathanielc/avi/nathanielc	[no test files]
-?   	github.com/nathanielc/avi/nav	[no test files]
-?   	github.com/nathanielc/avi/ships	[no test files]
diff --git a/cmd/avi/avi.go b/cmd/avi/avi.go
index 4101ced..b2f6a34 100644
--- a/cmd/avi/avi.go
+++ b/cmd/avi/avi.go
@@ -58,7 +58,9 @@ func main() {
 
 		s := snappy.NewReader(f)
 		updates := head.ProtoStreamUpdates(s)
-		head.Run(updates)
+		if err := head.Run(updates); err != nil {
+			log.Fatal(err)
+		}
 		return
 	}
 
@@ -115,7 +117,11 @@ func main() {
 	if *live {
 		ls := head.NewLiveStream()
 		drawer = head.NewProxyStream(drawer, ls)
-		go head.Run(ls.Updates())
+		go func() {
+			if err := head.Run(ls.Updates()); err != nil {
+				log.Fatal(err)
+			}
+		}()
 	}
 
 	sim, err := avi.NewSimulation(
diff --git a/head/head.go b/head/head.go
index d948f57..7dd5a1a 100644
--- a/head/head.go
+++ b/head/head.go
@@ -24,7 +24,25 @@ func init() {
 	flatShader, _ = gfxutil.OpenShader("head/models/flat")
 }
 
-func Run(updates <-chan FrameUpdate) {
+func Run(updates <-chan FrameUpdate) (err error) {
+	maxStartupRetries := 5
+	for maxStartupRetries > 0 {
+		if err = run(updates); err == nil {
+			// Technically run only returns if it errors, but this is for completeness
+			return
+		}
+		maxStartupRetries--
+	}
+	return
+}
+
+func run(updates <-chan FrameUpdate) (err error) {
+	defer func() {
+		r := recover()
+		if r != nil {
+			err = fmt.Errorf("starup error: %v", r)
+		}
+	}()
 	go func() {
 		// Create our window.
 		props := window.NewProps()
@@ -38,6 +56,7 @@ func Run(updates <-chan FrameUpdate) {
 		go gfxLoopWindow(w, r, updates)
 	}()
 	window.MainLoop()
+	return
 }
 
 func gfxLoopWindow(w window.Window, d gfx.Device, updates <-chan FrameUpdate) {