From d2309fa3a9b490feb4196df2b8114d2562de198b Mon Sep 17 00:00:00 2001
From: Yu-Han Yang <yuhany@google.com>
Date: Wed, 28 Sep 2022 22:58:51 +0000
Subject: [PATCH] Add passive listener support for GnssMeasurement

Bug: 248291428
Test: atest GnssMeasurementRegistrationTest
Change-Id: Ifac665ff1e85ee9625613e87548460c8974a81bc
---
 core/api/current.txt                           |  1 +
 .../location/GnssMeasurementRequest.java       | 18 ++++++++++++++++--
 .../gnss/GnssMeasurementsProvider.java         | 17 ++++++++++++-----
 3 files changed, 29 insertions(+), 7 deletions(-)

diff --git a/core/api/current.txt b/core/api/current.txt
index c7ca0cdaac5a0..6755e6444b600 100644
--- a/core/api/current.txt
+++ b/core/api/current.txt
@@ -19450,6 +19450,7 @@ package android.location {
     method public boolean isFullTracking();
     method public void writeToParcel(@NonNull android.os.Parcel, int);
     field @NonNull public static final android.os.Parcelable.Creator<android.location.GnssMeasurementRequest> CREATOR;
+    field public static final int PASSIVE_INTERVAL = 2147483647; // 0x7fffffff
   }
 
   public static final class GnssMeasurementRequest.Builder {
diff --git a/location/java/android/location/GnssMeasurementRequest.java b/location/java/android/location/GnssMeasurementRequest.java
index 71cb0e32a706c..a924b977f288d 100644
--- a/location/java/android/location/GnssMeasurementRequest.java
+++ b/location/java/android/location/GnssMeasurementRequest.java
@@ -31,6 +31,15 @@ import java.util.Objects;
  * This class contains extra parameters to pass in a GNSS measurement request.
  */
 public final class GnssMeasurementRequest implements Parcelable {
+    /**
+     * Represents a passive only request. Such a request will not trigger any active GNSS
+     * measurements or power usage itself, but may receive GNSS measurements generated in response
+     * to other requests.
+     *
+     * @see GnssMeasurementRequest#getIntervalMillis()
+     */
+    public static final int PASSIVE_INTERVAL = Integer.MAX_VALUE;
+
     private final boolean mCorrelationVectorOutputsEnabled;
     private final boolean mFullTracking;
     private final int mIntervalMillis;
@@ -76,7 +85,10 @@ public final class GnssMeasurementRequest implements Parcelable {
     }
 
     /**
-     * Represents the requested time interval between the reported measurements in milliseconds.
+     * Returns the requested time interval between the reported measurements in milliseconds, or
+     * {@link #PASSIVE_INTERVAL} if this is a passive, no power request. A passive request will not
+     * actively generate GNSS measurement updates, but may receive GNSS measurement updates
+     * generated as a result of other GNSS measurement requests.
      *
      * <p>If the time interval is not set, the default value is 0, which means the fastest rate the
      * GNSS chipset can report.
@@ -213,7 +225,9 @@ public final class GnssMeasurementRequest implements Parcelable {
 
         /**
          * Set the time interval between the reported measurements in milliseconds, which is 0 by
-         * default.
+         * default. The request interval may be set to {@link #PASSIVE_INTERVAL} which indicates
+         * this request will not actively generate GNSS measurement updates, but may receive
+         * GNSS measurement updates generated as a result of other GNSS measurement requests.
          *
          * <p>An interval of 0 milliseconds means the fastest rate the chipset can report.
          *
diff --git a/services/core/java/com/android/server/location/gnss/GnssMeasurementsProvider.java b/services/core/java/com/android/server/location/gnss/GnssMeasurementsProvider.java
index 9f2a9cf86fb69..07e9fe6ad5419 100644
--- a/services/core/java/com/android/server/location/gnss/GnssMeasurementsProvider.java
+++ b/services/core/java/com/android/server/location/gnss/GnssMeasurementsProvider.java
@@ -112,6 +112,9 @@ public final class GnssMeasurementsProvider extends
     @Override
     protected boolean registerWithService(GnssMeasurementRequest request,
             Collection<GnssListenerRegistration> registrations) {
+        if (request.getIntervalMillis() == GnssMeasurementRequest.PASSIVE_INTERVAL) {
+            return true;
+        }
         if (mGnssNative.startMeasurementCollection(request.isFullTracking(),
                 request.isCorrelationVectorOutputsEnabled(),
                 request.getIntervalMillis())) {
@@ -157,7 +160,7 @@ public final class GnssMeasurementsProvider extends
             Collection<GnssListenerRegistration> registrations) {
         boolean fullTracking = false;
         boolean enableCorrVecOutputs = false;
-        int intervalMillis = Integer.MAX_VALUE;
+        int intervalMillis = GnssMeasurementRequest.PASSIVE_INTERVAL;
 
         if (mSettingsHelper.isGnssMeasurementsFullTrackingEnabled()) {
             fullTracking = true;
@@ -165,6 +168,10 @@ public final class GnssMeasurementsProvider extends
 
         for (GnssListenerRegistration registration : registrations) {
             GnssMeasurementRequest request = registration.getRequest();
+            // passive requests do not contribute to the merged request
+            if (request.getIntervalMillis() == GnssMeasurementRequest.PASSIVE_INTERVAL) {
+                continue;
+            }
             if (request.isFullTracking()) {
                 fullTracking = true;
             }
@@ -175,10 +182,10 @@ public final class GnssMeasurementsProvider extends
         }
 
         return new GnssMeasurementRequest.Builder()
-                    .setFullTracking(fullTracking)
-                    .setCorrelationVectorOutputsEnabled(enableCorrVecOutputs)
-                    .setIntervalMillis(intervalMillis)
-                    .build();
+                .setFullTracking(fullTracking)
+                .setCorrelationVectorOutputsEnabled(enableCorrVecOutputs)
+                .setIntervalMillis(intervalMillis)
+                .build();
     }
 
     @Override