From 34fbbdeb9a5648df57b29dcd86496ca9b89ce80f Mon Sep 17 00:00:00 2001
From: Yu-Han Yang <yuhany@google.com>
Date: Wed, 20 Apr 2022 15:22:04 -0700
Subject: [PATCH] Allow injecting cached NTP time without network

Bug: 197038444
Test: manual
Change-Id: Ib47bc64e706201620edf6403da86338f6734dae4
---
 .../server/location/gnss/NtpTimeHelper.java   | 43 +++++++++++--------
 1 file changed, 25 insertions(+), 18 deletions(-)

diff --git a/services/core/java/com/android/server/location/gnss/NtpTimeHelper.java b/services/core/java/com/android/server/location/gnss/NtpTimeHelper.java
index 4a66516632a5f..8732065ea0093 100644
--- a/services/core/java/com/android/server/location/gnss/NtpTimeHelper.java
+++ b/services/core/java/com/android/server/location/gnss/NtpTimeHelper.java
@@ -73,7 +73,6 @@ class NtpTimeHelper {
     private final WakeLock mWakeLock;
     private final Handler mHandler;
 
-    @GuardedBy("this")
     private final InjectNtpTimeCallback mCallback;
 
     // flags to trigger NTP when network becomes available
@@ -129,6 +128,8 @@ class NtpTimeHelper {
             return;
         }
         if (!isNetworkConnected()) {
+            // try to inject the cached NTP time
+            injectCachedNtpTime();
             // try again when network is up
             mInjectNtpTimeState = STATE_PENDING_NETWORK;
             return;
@@ -157,23 +158,7 @@ class NtpTimeHelper {
 
             // only update when NTP time is fresh
             // If refreshSuccess is false, cacheAge does not drop down.
-            ntpResult = mNtpTime.getCachedTimeResult();
-            if (ntpResult != null && ntpResult.getAgeMillis() < NTP_INTERVAL) {
-                long time = ntpResult.getTimeMillis();
-                long timeReference = ntpResult.getElapsedRealtimeMillis();
-                long certainty = ntpResult.getCertaintyMillis();
-
-                if (DEBUG) {
-                    long now = System.currentTimeMillis();
-                    Log.d(TAG, "NTP server returned: "
-                            + time + " (" + new Date(time) + ")"
-                            + " ntpResult: " + ntpResult
-                            + " system time offset: " + (time - now));
-                }
-
-                // Ok to cast to int, as can't rollover in practice
-                mHandler.post(() -> mCallback.injectTime(time, timeReference, (int) certainty));
-
+            if (injectCachedNtpTime()) {
                 delay = NTP_INTERVAL;
                 mNtpBackOff.reset();
             } else {
@@ -201,4 +186,26 @@ class NtpTimeHelper {
         // release wake lock held by task
         mWakeLock.release();
     }
+
+    /** Returns true if successfully inject cached NTP time. */
+    private synchronized boolean injectCachedNtpTime() {
+        NtpTrustedTime.TimeResult ntpResult = mNtpTime.getCachedTimeResult();
+        if (ntpResult == null || ntpResult.getAgeMillis() >= NTP_INTERVAL) {
+            return false;
+        }
+
+        long time = ntpResult.getTimeMillis();
+        long timeReference = ntpResult.getElapsedRealtimeMillis();
+        long certainty = ntpResult.getCertaintyMillis();
+
+        if (DEBUG) {
+            long now = System.currentTimeMillis();
+            Log.d(TAG, "NTP server returned: " + time + " (" + new Date(time) + ")"
+                    + " ntpResult: " + ntpResult + " system time offset: " + (time - now));
+        }
+
+        // Ok to cast to int, as can't rollover in practice
+        mHandler.post(() -> mCallback.injectTime(time, timeReference, (int) certainty));
+        return true;
+    }
 }