From 7e79d05d9eee479664f7b5819a1f788ea12e039e Mon Sep 17 00:00:00 2001
From: Burcu Dogan <jbd@google.com>
Date: Wed, 2 Sep 2015 22:39:10 -0700
Subject: [PATCH] exp/sensor: set sensor interval on ios

Change-Id: I5559f721b2e2c7506db89f804569c0b0f78abea8
Reviewed-on: https://go-review.googlesource.com/14251
Reviewed-by: Nigel Tao <nigeltao@golang.org>
---
 exp/sensor/darwin_armx.go | 6 +++---
 exp/sensor/darwin_armx.m  | 3 ++-
 exp/sensor/sensor.go      | 2 ++
 3 files changed, 7 insertions(+), 4 deletions(-)

diff --git a/exp/sensor/darwin_armx.go b/exp/sensor/darwin_armx.go
index ac15f05..c5299a5 100644
--- a/exp/sensor/darwin_armx.go
+++ b/exp/sensor/darwin_armx.go
@@ -15,12 +15,11 @@ package sensor
 
 void GoIOS_createManager();
 
-void GoIOS_startAccelerometer();
+void GoIOS_startAccelerometer(float interval);
 void GoIOS_stopAccelerometer();
 void GoIOS_readAccelerometer(int64_t* timestamp, float* vector);
 
 void GoIOS_destroyManager();
-
 */
 import "C"
 import (
@@ -55,7 +54,8 @@ func (m *manager) enable(s Sender, t Type, delay time.Duration) error {
 			return fmt.Errorf("sensor: cannot enable; %v sensor is already enabled", t)
 		}
 		// TODO(jbd): Check if accelerometer is available.
-		C.GoIOS_startAccelerometer()
+		interval := float64(delay) / float64(time.Second)
+		C.GoIOS_startAccelerometer(C.float(interval))
 		channels.acceleroDone = make(chan struct{})
 		go m.runAccelerometer(s, delay, channels.acceleroDone)
 	case Gyroscope:
diff --git a/exp/sensor/darwin_armx.m b/exp/sensor/darwin_armx.m
index 3c5be36..654e6ae 100644
--- a/exp/sensor/darwin_armx.m
+++ b/exp/sensor/darwin_armx.m
@@ -13,7 +13,8 @@ void GoIOS_createManager() {
   manager = [[CMMotionManager alloc] init];
 }
 
-void GoIOS_startAccelerometer() {
+void GoIOS_startAccelerometer(float interval) {
+  manager.accelerometerUpdateInterval = interval;
   [manager startAccelerometerUpdates];
 }
 
diff --git a/exp/sensor/sensor.go b/exp/sensor/sensor.go
index 1cd91ec..90ec7ed 100644
--- a/exp/sensor/sensor.go
+++ b/exp/sensor/sensor.go
@@ -76,6 +76,7 @@ var m = newManager()
 // Enable enables the specified sensor type with the given delay rate.
 // Sensor events will be sent to s, a typical example of Sender
 // implementations is app.App.
+// Enable is not safe for concurrent use.
 func Enable(s Sender, t Type, delay time.Duration) error {
 	if t < 0 || int(t) >= len(sensorNames) {
 		return errors.New("sensor: unknown sensor type")
@@ -84,6 +85,7 @@ func Enable(s Sender, t Type, delay time.Duration) error {
 }
 
 // Disable disables to feed the manager with the specified sensor.
+// Disable is not safe for concurrent use.
 func Disable(t Type) error {
 	if t < 0 || int(t) >= len(sensorNames) {
 		return errors.New("sensor: unknown sensor type")