[VCN02] Make LingerTimer takes request Id instead of NetworkRequest

Currently, LingerTimer takes a NetworkRequest for internal use.
However, this is unnecessary since only request Id is used.

Thus, this patch allows subsequent patches to remove the need
of a NetworkRequest when creating a LingerTimer. And the output
of lingered requests is reduced to id instead of printing
content of requests.

Test: atest FrameworksNetTests
Bug: 175180558
Change-Id: I9106d0804f1083942e1fcaca842f547c0aee1840
diff --git a/core/java/android/net/NetworkRequest.java b/core/java/android/net/NetworkRequest.java
index dc16d74..f0c637c 100644
--- a/core/java/android/net/NetworkRequest.java
+++ b/core/java/android/net/NetworkRequest.java
@@ -40,6 +40,18 @@
  */
 public class NetworkRequest implements Parcelable {
     /**
+     * The first requestId value that will be allocated.
+     * @hide only used by ConnectivityService.
+     */
+    public static final int FIRST_REQUEST_ID = 1;
+
+    /**
+     * The requestId value that represents the absence of a request.
+     * @hide only used by ConnectivityService.
+     */
+    public static final int REQUEST_ID_NONE = -1;
+
+    /**
      * The {@link NetworkCapabilities} that define this request.
      * @hide
      */
diff --git a/services/core/java/com/android/server/ConnectivityService.java b/services/core/java/com/android/server/ConnectivityService.java
index fe116d9..683393b 100644
--- a/services/core/java/com/android/server/ConnectivityService.java
+++ b/services/core/java/com/android/server/ConnectivityService.java
@@ -624,7 +624,7 @@
     private LingerMonitor mLingerMonitor;
 
     // sequence number of NetworkRequests
-    private int mNextNetworkRequestId = 1;
+    private int mNextNetworkRequestId = NetworkRequest.FIRST_REQUEST_ID;
 
     // Sequence number for NetworkProvider IDs.
     private final AtomicInteger mNextNetworkProviderId = new AtomicInteger(
@@ -1247,6 +1247,8 @@
     }
 
     private synchronized int nextNetworkRequestId() {
+        // TODO: Consider handle wrapping and exclude {@link NetworkRequest#REQUEST_ID_NONE} if
+        //  doing that.
         return mNextNetworkRequestId++;
     }
 
@@ -7097,11 +7099,11 @@
                     log("   accepting network in place of " + previousSatisfier.toShortString());
                 }
                 previousSatisfier.removeRequest(nri.request.requestId);
-                previousSatisfier.lingerRequest(nri.request, now, mLingerDelayMs);
+                previousSatisfier.lingerRequest(nri.request.requestId, now, mLingerDelayMs);
             } else {
                 if (VDBG || DDBG) log("   accepting network in place of null");
             }
-            newSatisfier.unlingerRequest(nri.request);
+            newSatisfier.unlingerRequest(nri.request.requestId);
             if (!newSatisfier.addRequest(nri.request)) {
                 Log.wtf(TAG, "BUG: " + newSatisfier.toShortString() + " already has "
                         + nri.request);
diff --git a/services/core/java/com/android/server/connectivity/NetworkAgentInfo.java b/services/core/java/com/android/server/connectivity/NetworkAgentInfo.java
index 52b9f5c..13629c2 100644
--- a/services/core/java/com/android/server/connectivity/NetworkAgentInfo.java
+++ b/services/core/java/com/android/server/connectivity/NetworkAgentInfo.java
@@ -188,28 +188,28 @@
     // either the linger timeout expiring and the network being taken down, or the network
     // satisfying a request again.
     public static class LingerTimer implements Comparable<LingerTimer> {
-        public final NetworkRequest request;
+        public final int requestId;
         public final long expiryMs;
 
-        public LingerTimer(NetworkRequest request, long expiryMs) {
-            this.request = request;
+        public LingerTimer(int requestId, long expiryMs) {
+            this.requestId = requestId;
             this.expiryMs = expiryMs;
         }
         public boolean equals(Object o) {
             if (!(o instanceof LingerTimer)) return false;
             LingerTimer other = (LingerTimer) o;
-            return (request.requestId == other.request.requestId) && (expiryMs == other.expiryMs);
+            return (requestId == other.requestId) && (expiryMs == other.expiryMs);
         }
         public int hashCode() {
-            return Objects.hash(request.requestId, expiryMs);
+            return Objects.hash(requestId, expiryMs);
         }
         public int compareTo(LingerTimer other) {
             return (expiryMs != other.expiryMs) ?
                     Long.compare(expiryMs, other.expiryMs) :
-                    Integer.compare(request.requestId, other.request.requestId);
+                    Integer.compare(requestId, other.requestId);
         }
         public String toString() {
-            return String.format("%s, expires %dms", request.toString(),
+            return String.format("%s, expires %dms", requestId,
                     expiryMs - SystemClock.elapsedRealtime());
         }
     }
@@ -411,7 +411,7 @@
         updateRequestCounts(REMOVE, existing);
         mNetworkRequests.remove(requestId);
         if (existing.isRequest()) {
-            unlingerRequest(existing);
+            unlingerRequest(existing.requestId);
         }
     }
 
@@ -557,33 +557,33 @@
     }
 
     /**
-     * Sets the specified request to linger on this network for the specified time. Called by
+     * Sets the specified requestId to linger on this network for the specified time. Called by
      * ConnectivityService when the request is moved to another network with a higher score.
      */
-    public void lingerRequest(NetworkRequest request, long now, long duration) {
-        if (mLingerTimerForRequest.get(request.requestId) != null) {
+    public void lingerRequest(int requestId, long now, long duration) {
+        if (mLingerTimerForRequest.get(requestId) != null) {
             // Cannot happen. Once a request is lingering on a particular network, we cannot
             // re-linger it unless that network becomes the best for that request again, in which
             // case we should have unlingered it.
-            Log.wtf(TAG, toShortString() + ": request " + request.requestId + " already lingered");
+            Log.wtf(TAG, toShortString() + ": request " + requestId + " already lingered");
         }
         final long expiryMs = now + duration;
-        LingerTimer timer = new LingerTimer(request, expiryMs);
+        LingerTimer timer = new LingerTimer(requestId, expiryMs);
         if (VDBG) Log.d(TAG, "Adding LingerTimer " + timer + " to " + toShortString());
         mLingerTimers.add(timer);
-        mLingerTimerForRequest.put(request.requestId, timer);
+        mLingerTimerForRequest.put(requestId, timer);
     }
 
     /**
      * Cancel lingering. Called by ConnectivityService when a request is added to this network.
-     * Returns true if the given request was lingering on this network, false otherwise.
+     * Returns true if the given requestId was lingering on this network, false otherwise.
      */
-    public boolean unlingerRequest(NetworkRequest request) {
-        LingerTimer timer = mLingerTimerForRequest.get(request.requestId);
+    public boolean unlingerRequest(int requestId) {
+        LingerTimer timer = mLingerTimerForRequest.get(requestId);
         if (timer != null) {
             if (VDBG) Log.d(TAG, "Removing LingerTimer " + timer + " from " + toShortString());
             mLingerTimers.remove(timer);
-            mLingerTimerForRequest.remove(request.requestId);
+            mLingerTimerForRequest.remove(requestId);
             return true;
         }
         return false;