More cleanly separate requests and listens.

Currently, NetworkRequest has several types of requests (LISTEN,
TRACK_DEFAULT, REQUEST, BACKGROUND_REQUEST), and we expect more
to be added.

There are really three categories of request:
1. Requests satisfied by only one network and will keep that
   network up, and thus need to be sent to NetworkProviders:
   REQUEST, BACKGROUND_REQUEST.
2. Requests satisfied by only one network but will not keep that
   network up: TRACK_DEFAULT
3. Requests satisfied by multiple networks and will not keep any
   networks up: LISTEN.

Unfortunately the separation is not very clear. Currently, for
any valid request, either isListen() will return true or
isRequest() will return true. This makes it impossible to tell
whether a particular request should be sent to NetworkProviders,
so the current code sends TRACK_DEFAULT requests to
NetworkProviders as well. This is incorrect - a TRACK_DEFAULT
should never keep a network up, for example.

This CL attempts to clarify things by making isRequest() return
false for TRACK_DEFAULT requests and thus never sending them to
NetworkProviders. After this CL:

- isRequest will return true only for requests that attempt to
  bring up or keep up a network.
- isListen will return true only for requests that match multiple
  networks but do not keep any of them up.
- Neither will return true for TRACK_DEFAULT.

Test: atest ConnectivityServiceTest
Change-Id: I7aad30ade8f7ab2a179e53483d9afd8675f64a12

framework/src/android/net/NetworkRequest.java

@@ -435,25 +435,7 @@ public class NetworkRequest implements Parcelable {
      * @hide
      */
     public boolean isRequest() {
-        return isForegroundRequest() || isBackgroundRequest();
-    }
-
-    /**
-     * Returns true iff. the contained NetworkRequest is one that:
-     *
-     *     - should be associated with at most one satisfying network
-     *       at a time;
-     *
-     *     - should cause a network to be kept up and in the foreground if
-     *       it is the best network which can satisfy the NetworkRequest.
-     *
-     * For full detail of how isRequest() is used for pairing Networks with
-     * NetworkRequests read rematchNetworkAndRequests().
-     *
-     * @hide
-     */
-    public boolean isForegroundRequest() {
-        return type == Type.TRACK_DEFAULT || type == Type.REQUEST;
+        return type == Type.REQUEST || type == Type.BACKGROUND_REQUEST;
     }
 
     /**

services/core/java/com/android/server/ConnectivityService.java

@@ -3588,10 +3588,7 @@ public class ConnectivityService extends IConnectivityManager.Stub
         // As this request was not satisfied on rematch and thus never had any scores sent to the
         // factories, send null now for each request of type REQUEST.
         for (final NetworkRequest req : nri.mRequests) {
-            if (!req.isRequest()) {
-                continue;
-            }
-            sendUpdatedScoreToFactories(req, null);
+            if (req.isRequest()) sendUpdatedScoreToFactories(req, null);
         }
     }
 
@@ -3768,7 +3765,7 @@ public class ConnectivityService extends IConnectivityManager.Stub
         mNetworkRequestInfoLogs.log("RELEASE " + nri);
 
         if (null != nri.getActiveRequest()) {
-            if (nri.getActiveRequest().isRequest()) {
+            if (!nri.getActiveRequest().isListen()) {
                 removeSatisfiedNetworkRequestFromNetwork(nri);
             } else {
                 nri.setSatisfier(null, null);
@@ -5516,7 +5513,7 @@ public class ConnectivityService extends IConnectivityManager.Stub
         }
 
         // The network currently satisfying this NRI. Only one request in an NRI can have a
-        // satisfier. For non-multilayer requests, only REQUEST-type requests can have a satisfier.
+        // satisfier. For non-multilayer requests, only non-listen requests can have a satisfier.
         @Nullable
         private NetworkAgentInfo mSatisfier;
         NetworkAgentInfo getSatisfier() {
@@ -7004,8 +7001,8 @@ public class ConnectivityService extends IConnectivityManager.Stub
     private void sendUpdatedScoreToFactories(NetworkAgentInfo nai) {
         for (int i = 0; i < nai.numNetworkRequests(); i++) {
             NetworkRequest nr = nai.requestAt(i);
-            // Don't send listening requests to factories. b/17393458
-            if (nr.isListen()) continue;
+            // Don't send listening or track default request to factories. b/17393458
+            if (!nr.isRequest()) continue;
             sendUpdatedScoreToFactories(nr, nai);
         }
     }
@@ -7067,10 +7064,10 @@ public class ConnectivityService extends IConnectivityManager.Stub
         ensureRunningOnConnectivityServiceThread();
         for (final NetworkRequestInfo nri : getNrisFromGlobalRequests()) {
             for (final NetworkRequest req : nri.mRequests) {
-                if (req.isListen() && nri.getActiveRequest() == req) {
+                if (!req.isRequest() && nri.getActiveRequest() == req) {
                     break;
                 }
-                if (req.isListen()) {
+                if (!req.isRequest()) {
                     continue;
                 }
                 // Only set the nai for the request it is satisfying.
@@ -7220,8 +7217,8 @@ public class ConnectivityService extends IConnectivityManager.Stub
         if (nai.numRequestNetworkRequests() != 0) {
             for (int i = 0; i < nai.numNetworkRequests(); i++) {
                 NetworkRequest nr = nai.requestAt(i);
-                // Ignore listening requests.
-                if (nr.isListen()) continue;
+                // Ignore listening and track default requests.
+                if (!nr.isRequest()) continue;
                 loge("Dead network still had at least " + nr);
                 break;
             }