[VCN09] Rename linger timer

Linger timer mechanism will be used for both "linger" and
"nascent" states. To prevent confusion, rename the linger
timer and related functions to more generic name.

Test: TH
Bug: 175180558
Change-Id: I652f7c65c2f8bc58fb9d3316480f23a9709eccce
diff --git a/services/core/java/com/android/server/ConnectivityService.java b/services/core/java/com/android/server/ConnectivityService.java
index 96c3e57..8912fd7 100644
--- a/services/core/java/com/android/server/ConnectivityService.java
+++ b/services/core/java/com/android/server/ConnectivityService.java
@@ -2703,9 +2703,9 @@
                 pw.println(nai.requestAt(i).toString());
             }
             pw.decreaseIndent();
-            pw.println("Lingered:");
+            pw.println("Inactivity Timers:");
             pw.increaseIndent();
-            nai.dumpLingerTimers(pw);
+            nai.dumpInactivityTimers(pw);
             pw.decreaseIndent();
             pw.decreaseIndent();
         }
@@ -3300,27 +3300,27 @@
     }
 
     /**
-     * Updates the linger state from the network requests inside the NAI.
+     * Updates the inactivity state from the network requests inside the NAI.
      * @param nai the agent info to update
      * @param now the timestamp of the event causing this update
-     * @return whether the network was lingered as a result of this update
+     * @return whether the network was inactive as a result of this update
      */
-    private boolean updateLingerState(@NonNull final NetworkAgentInfo nai, final long now) {
-        // 1. Update the linger timer. If it's changed, reschedule or cancel the alarm.
-        // 2. If the network was lingering and there are now requests, unlinger it.
+    private boolean updateInactivityState(@NonNull final NetworkAgentInfo nai, final long now) {
+        // 1. Update the inactivity timer. If it's changed, reschedule or cancel the alarm.
+        // 2. If the network was inactive and there are now requests, unset inactive.
         // 3. If this network is unneeded (which implies it is not lingering), and there is at least
-        //    one lingered request, start lingering.
-        nai.updateLingerTimer();
+        //    one lingered request, set inactive.
+        nai.updateInactivityTimer();
         if (nai.isLingering() && nai.numForegroundNetworkRequests() > 0) {
-            if (DBG) log("Unlingering " + nai.toShortString());
-            nai.unlinger();
+            if (DBG) log("Unsetting inactive " + nai.toShortString());
+            nai.unsetInactive();
             logNetworkEvent(nai, NetworkEvent.NETWORK_UNLINGER);
-        } else if (unneeded(nai, UnneededFor.LINGER) && nai.getLingerExpiry() > 0) {
+        } else if (unneeded(nai, UnneededFor.LINGER) && nai.getInactivityExpiry() > 0) {
             if (DBG) {
-                final int lingerTime = (int) (nai.getLingerExpiry() - now);
-                log("Lingering " + nai.toShortString() + " for " + lingerTime + "ms");
+                final int lingerTime = (int) (nai.getInactivityExpiry() - now);
+                log("Setting inactive " + nai.toShortString() + " for " + lingerTime + "ms");
             }
-            nai.linger();
+            nai.setInactive();
             logNetworkEvent(nai, NetworkEvent.NETWORK_LINGER);
             return true;
         }
@@ -3456,7 +3456,7 @@
                 }
             }
         }
-        nai.clearLingerState();
+        nai.clearInactivityState();
         // TODO: mLegacyTypeTracker.remove seems redundant given there's a full rematch right after.
         //  Currently, deleting it breaks tests that check for the fallback network disconnecting.
         //  Find out why, fix the rematch code, and delete this.
@@ -3799,7 +3799,7 @@
             // If there are still lingered requests on this network, don't tear it down,
             // but resume lingering instead.
             final long now = SystemClock.elapsedRealtime();
-            if (updateLingerState(nai, now)) {
+            if (updateInactivityState(nai, now)) {
                 notifyNetworkLosing(nai, now);
             }
             if (unneeded(nai, UnneededFor.TEARDOWN)) {
@@ -7186,7 +7186,7 @@
 
         // If we get here it means that the last linger timeout for this network expired. So there
         // must be no other active linger timers, and we must stop lingering.
-        oldNetwork.clearLingerState();
+        oldNetwork.clearInactivityState();
 
         if (unneeded(oldNetwork, UnneededFor.TEARDOWN)) {
             // Tear the network down.
@@ -7557,7 +7557,7 @@
             // if the state has not changed : the source of truth is controlled with
             // NetworkAgentInfo#lingerRequest and NetworkAgentInfo#unlingerRequest, which have been
             // called while rematching the individual networks above.
-            if (updateLingerState(nai, now)) {
+            if (updateInactivityState(nai, now)) {
                 lingeredNetworks.add(nai);
             }
         }
@@ -7584,7 +7584,7 @@
         // Tear down all unneeded networks.
         for (NetworkAgentInfo nai : mNetworkAgentInfos) {
             if (unneeded(nai, UnneededFor.TEARDOWN)) {
-                if (nai.getLingerExpiry() > 0) {
+                if (nai.getInactivityExpiry() > 0) {
                     // This network has active linger timers and no requests, but is not
                     // lingering. Linger it.
                     //
@@ -7592,7 +7592,7 @@
                     // and became unneeded due to another network improving its score to the
                     // point where this network will no longer be able to satisfy any requests
                     // even if it validates.
-                    if (updateLingerState(nai, now)) {
+                    if (updateInactivityState(nai, now)) {
                         notifyNetworkLosing(nai, now);
                     }
                 } else {
@@ -7869,7 +7869,7 @@
 
     // Notify the requests on this NAI that the network is now lingered.
     private void notifyNetworkLosing(@NonNull final NetworkAgentInfo nai, final long now) {
-        final int lingerTime = (int) (nai.getLingerExpiry() - now);
+        final int lingerTime = (int) (nai.getInactivityExpiry() - now);
         notifyNetworkCallbacks(nai, ConnectivityManager.CALLBACK_LOSING, lingerTime);
     }
 
diff --git a/services/core/java/com/android/server/connectivity/NetworkAgentInfo.java b/services/core/java/com/android/server/connectivity/NetworkAgentInfo.java
index 1a4f20c..a9a705f 100644
--- a/services/core/java/com/android/server/connectivity/NetworkAgentInfo.java
+++ b/services/core/java/com/android/server/connectivity/NetworkAgentInfo.java
@@ -210,23 +210,23 @@
     // network is taken down.  This usually only happens to the default network. Lingering ends with
     // 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 static class InactivityTimer implements Comparable<InactivityTimer> {
         public final int requestId;
         public final long expiryMs;
 
-        public LingerTimer(int requestId, long expiryMs) {
+        public InactivityTimer(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;
+            if (!(o instanceof InactivityTimer)) return false;
+            InactivityTimer other = (InactivityTimer) o;
             return (requestId == other.requestId) && (expiryMs == other.expiryMs);
         }
         public int hashCode() {
             return Objects.hash(requestId, expiryMs);
         }
-        public int compareTo(LingerTimer other) {
+        public int compareTo(InactivityTimer other) {
             return (expiryMs != other.expiryMs) ?
                     Long.compare(expiryMs, other.expiryMs) :
                     Integer.compare(requestId, other.requestId);
@@ -269,30 +269,31 @@
      */
     public static final int ARG_AGENT_SUCCESS = 1;
 
-    // All linger timers for this network, sorted by expiry time. A linger timer is added whenever
+    // All inactivity timers for this network, sorted by expiry time. A timer is added whenever
     // a request is moved to a network with a better score, regardless of whether the network is or
     // was lingering or not.
     // TODO: determine if we can replace this with a smaller or unsorted data structure. (e.g.,
     // SparseLongArray) combined with the timestamp of when the last timer is scheduled to fire.
-    private final SortedSet<LingerTimer> mLingerTimers = new TreeSet<>();
+    private final SortedSet<InactivityTimer> mInactivityTimers = new TreeSet<>();
 
-    // For fast lookups. Indexes into mLingerTimers by request ID.
-    private final SparseArray<LingerTimer> mLingerTimerForRequest = new SparseArray<>();
+    // For fast lookups. Indexes into mInactivityTimers by request ID.
+    private final SparseArray<InactivityTimer> mInactivityTimerForRequest = new SparseArray<>();
 
-    // Linger expiry timer. Armed whenever mLingerTimers is non-empty, regardless of whether the
-    // network is lingering or not. Always set to the expiry of the LingerTimer that expires last.
-    // When the timer fires, all linger state is cleared, and if the network has no requests, it is
-    // torn down.
-    private WakeupMessage mLingerMessage;
+    // Inactivity expiry timer. Armed whenever mInactivityTimers is non-empty, regardless of
+    // whether the network is inactive or not. Always set to the expiry of the mInactivityTimers
+    // that expires last. When the timer fires, all inactivity state is cleared, and if the network
+    // has no requests, it is torn down.
+    private WakeupMessage mInactivityMessage;
 
-    // Linger expiry. Holds the expiry time of the linger timer, or 0 if the timer is not armed.
-    private long mLingerExpiryMs;
+    // Inactivity expiry. Holds the expiry time of the inactivity timer, or 0 if the timer is not
+    // armed.
+    private long mInactivityExpiryMs;
 
-    // Whether the network is lingering or not. Must be maintained separately from the above because
+    // Whether the network is inactive or not. Must be maintained separately from the above because
     // it depends on the state of other networks and requests, which only ConnectivityService knows.
     // (Example: we don't linger a network if it would become the best for a NetworkRequest if it
     // validated).
-    private boolean mLingering;
+    private boolean mInactive;
 
     // This represents the quality of the network with no clear scale.
     private int mScore;
@@ -898,17 +899,17 @@
      * ConnectivityService when the request is moved to another network with a higher score.
      */
     public void lingerRequest(int requestId, long now, long duration) {
-        if (mLingerTimerForRequest.get(requestId) != null) {
+        if (mInactivityTimerForRequest.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 " + requestId + " already lingered");
         }
         final long expiryMs = now + duration;
-        LingerTimer timer = new LingerTimer(requestId, expiryMs);
-        if (VDBG) Log.d(TAG, "Adding LingerTimer " + timer + " to " + toShortString());
-        mLingerTimers.add(timer);
-        mLingerTimerForRequest.put(requestId, timer);
+        InactivityTimer timer = new InactivityTimer(requestId, expiryMs);
+        if (VDBG) Log.d(TAG, "Adding InactivityTimer " + timer + " to " + toShortString());
+        mInactivityTimers.add(timer);
+        mInactivityTimerForRequest.put(requestId, timer);
     }
 
     /**
@@ -916,23 +917,25 @@
      * Returns true if the given requestId was lingering on this network, false otherwise.
      */
     public boolean unlingerRequest(int requestId) {
-        LingerTimer timer = mLingerTimerForRequest.get(requestId);
+        InactivityTimer timer = mInactivityTimerForRequest.get(requestId);
         if (timer != null) {
-            if (VDBG) Log.d(TAG, "Removing LingerTimer " + timer + " from " + toShortString());
-            mLingerTimers.remove(timer);
-            mLingerTimerForRequest.remove(requestId);
+            if (VDBG) {
+                Log.d(TAG, "Removing InactivityTimer " + timer + " from " + toShortString());
+            }
+            mInactivityTimers.remove(timer);
+            mInactivityTimerForRequest.remove(requestId);
             return true;
         }
         return false;
     }
 
-    public long getLingerExpiry() {
-        return mLingerExpiryMs;
+    public long getInactivityExpiry() {
+        return mInactivityExpiryMs;
     }
 
-    public void updateLingerTimer() {
-        long newExpiry = mLingerTimers.isEmpty() ? 0 : mLingerTimers.last().expiryMs;
-        if (newExpiry == mLingerExpiryMs) return;
+    public void updateInactivityTimer() {
+        long newExpiry = mInactivityTimers.isEmpty() ? 0 : mInactivityTimers.last().expiryMs;
+        if (newExpiry == mInactivityExpiryMs) return;
 
         // Even if we're going to reschedule the timer, cancel it first. This is because the
         // semantics of WakeupMessage guarantee that if cancel is called then the alarm will
@@ -940,49 +943,52 @@
         // WakeupMessage makes no such guarantees about rescheduling a message, so if mLingerMessage
         // has already been dispatched, rescheduling to some time in the future won't stop it
         // from calling its callback immediately.
-        if (mLingerMessage != null) {
-            mLingerMessage.cancel();
-            mLingerMessage = null;
+        if (mInactivityMessage != null) {
+            mInactivityMessage.cancel();
+            mInactivityMessage = null;
         }
 
         if (newExpiry > 0) {
-            mLingerMessage = new WakeupMessage(
+            mInactivityMessage = new WakeupMessage(
                     mContext, mHandler,
                     "NETWORK_LINGER_COMPLETE." + network.getNetId() /* cmdName */,
                     EVENT_NETWORK_LINGER_COMPLETE /* cmd */,
                     0 /* arg1 (unused) */, 0 /* arg2 (unused) */,
                     this /* obj (NetworkAgentInfo) */);
-            mLingerMessage.schedule(newExpiry);
+            mInactivityMessage.schedule(newExpiry);
         }
 
-        mLingerExpiryMs = newExpiry;
+        mInactivityExpiryMs = newExpiry;
     }
 
-    public void linger() {
-        mLingering = true;
+    public void setInactive() {
+        mInactive = true;
     }
 
-    public void unlinger() {
-        mLingering = false;
+    public void unsetInactive() {
+        mInactive = false;
     }
 
     public boolean isLingering() {
-        return mLingering;
+        return mInactive;
     }
 
-    public void clearLingerState() {
-        if (mLingerMessage != null) {
-            mLingerMessage.cancel();
-            mLingerMessage = null;
+    public void clearInactivityState() {
+        if (mInactivityMessage != null) {
+            mInactivityMessage.cancel();
+            mInactivityMessage = null;
         }
-        mLingerTimers.clear();
-        mLingerTimerForRequest.clear();
-        updateLingerTimer();  // Sets mLingerExpiryMs, cancels and nulls out mLingerMessage.
-        mLingering = false;
+        mInactivityTimers.clear();
+        mInactivityTimerForRequest.clear();
+        // Sets mInactivityExpiryMs, cancels and nulls out mInactivityMessage.
+        updateInactivityTimer();
+        mInactive = false;
     }
 
-    public void dumpLingerTimers(PrintWriter pw) {
-        for (LingerTimer timer : mLingerTimers) { pw.println(timer); }
+    public void dumpInactivityTimers(PrintWriter pw) {
+        for (InactivityTimer timer : mInactivityTimers) {
+            pw.println(timer);
+        }
     }
 
     /**