From 97b1dae34753b900c65e8420c1e85098aaf47d74 Mon Sep 17 00:00:00 2001
From: Neagu Bogdan <neagubogdanioan@yahoo.com>
Date: Sat, 21 May 2016 20:01:27 +0300
Subject: [PATCH] Added timeout to TimePulse

---
 host/generic/digitalpin.go | 16 ++++++++++++++++
 1 file changed, 16 insertions(+)

diff --git a/host/generic/digitalpin.go b/host/generic/digitalpin.go
index 80a81ea..2e00845 100644
--- a/host/generic/digitalpin.go
+++ b/host/generic/digitalpin.go
@@ -15,6 +15,8 @@ import (
 	"github.com/kidoman/embd"
 )
 
+const timeoutInterval = 10000000
+
 type digitalPin struct {
 	id string
 	n  int
@@ -165,6 +167,8 @@ func (p *digitalPin) TimePulse(state int) (time.Duration, error) {
 		aroundState = embd.High
 	}
 
+	initTime := time.Now()
+
 	// Wait for any previous pulse to end
 	for {
 		v, err := p.read()
@@ -175,6 +179,10 @@ func (p *digitalPin) TimePulse(state int) (time.Duration, error) {
 		if v == aroundState {
 			break
 		}
+
+		if time.Since(initTime).Nanoseconds() > timeoutInterval {
+			return 0, nil
+		}
 	}
 
 	// Wait until ECHO goes high
@@ -187,6 +195,10 @@ func (p *digitalPin) TimePulse(state int) (time.Duration, error) {
 		if v == state {
 			break
 		}
+
+		if time.Since(initTime).Nanoseconds() > timeoutInterval {
+			return 0, nil
+		}
 	}
 
 	startTime := time.Now() // Record time when ECHO goes high
@@ -201,6 +213,10 @@ func (p *digitalPin) TimePulse(state int) (time.Duration, error) {
 		if v == aroundState {
 			break
 		}
+
+		if time.Since(initTime).Nanoseconds() > timeoutInterval {
+			return 0, nil
+		}
 	}
 
 	return time.Since(startTime), nil // Calculate time lapsed for ECHO to transition from high to low