Refactored ContentCaptureService (and infra) to have just one RemoteService.

The initial implementation of AbstractPerUserService assumed the
AbstractRemoteService instances would be created in demand, because that was
the aproach used by Autofill (to minimize the time system service is bound to
the autofill service process).

But for other systems like ContentCapture, it makes more sense to keep a
permanent connection to the remote service, which is running all the time, so
this change changes the infra to allow such permanent connection (which includes
defining an idle timeout value that never unbinds).

Bug: 117779333
Test: atest CtsContentCaptureServiceTestCases CtsAutoFillServiceTestCases

Change-Id: I43386a3fddc56f1dfd6e4e55f243eaa297921123

core/java/com/android/internal/infra/AbstractRemoteService.java

@@ -33,6 +33,7 @@ import android.os.RemoteException;
 import android.os.SystemClock;
 import android.os.UserHandle;
 import android.util.Slog;
+import android.util.TimeUtils;
 
 import com.android.internal.annotations.GuardedBy;
 
@@ -64,6 +65,8 @@ public abstract class AbstractRemoteService<S extends AbstractRemoteService<S, I
         I extends IInterface> implements DeathRecipient {
     private static final int MSG_UNBIND = 1;
 
+    protected static final long PERMANENT_BOUND_TIMEOUT_MS = 0;
+
     protected static final int LAST_PRIVATE_MSG = MSG_UNBIND;
 
     // TODO(b/117779333): convert all booleans into an integer / flags
@@ -86,6 +89,9 @@ public abstract class AbstractRemoteService<S extends AbstractRemoteService<S, I
     private boolean mServiceDied;
     private boolean mCompleted;
 
+    // Used just for debugging purposes (on dump)
+    private long mNextUnbind;
+
     /**
      * Callback called when the service dies.
      *
@@ -156,7 +162,9 @@ public abstract class AbstractRemoteService<S extends AbstractRemoteService<S, I
     protected abstract I getServiceInterface(@NonNull IBinder service);
 
     /**
-     * Defines How long after the last interaction with the service we would unbind.
+     * Defines how long after the last interaction with the service we would unbind.
+     *
+     * @return time to unbind (in millis), or {@link #PERMANENT_BOUND_TIMEOUT_MS} to not unbind.
      */
     protected abstract long getTimeoutIdleBindMillis();
 
@@ -220,11 +228,23 @@ public abstract class AbstractRemoteService<S extends AbstractRemoteService<S, I
                 .append(mComponentName.flattenToString()).println();
         pw.append(prefix).append(tab).append("destroyed=")
                 .append(String.valueOf(mDestroyed)).println();
+        final boolean bound = handleIsBound();
         pw.append(prefix).append(tab).append("bound=")
-                .append(String.valueOf(handleIsBound())).println();
+                .append(String.valueOf(bound));
+        final long idleTimeout = getTimeoutIdleBindMillis();
+        if (bound) {
+            if (idleTimeout > 0) {
+                pw.append(" (unbind in : ");
+                TimeUtils.formatDuration(mNextUnbind - SystemClock.elapsedRealtime(), pw);
+                pw.append(")");
+            } else {
+                pw.append(" (permanently bound)");
+            }
+        }
+        pw.println();
         pw.append(prefix).append("mBindInstantServiceAllowed=").println(mBindInstantServiceAllowed);
         pw.append(prefix).append("idleTimeout=")
-            .append(Long.toString(getTimeoutIdleBindMillis() / 1000)).append("s").println();
+            .append(Long.toString(idleTimeout / 1000)).append("s").println();
         pw.append(prefix).append("requestTimeout=")
             .append(Long.toString(getRemoteRequestMillis() / 1000)).append("s").println();
         pw.println();
@@ -236,6 +256,8 @@ public abstract class AbstractRemoteService<S extends AbstractRemoteService<S, I
      * <p>This request must be responded by the service somehow (typically using a callback),
      * othewise it will trigger a {@link PendingRequest#onTimeout(AbstractRemoteService)} if the
      * service doesn't respond.
+     *
+     * <p><b>NOTE: </b>this request is responsible for calling {@link #scheduleUnbind()}.
      */
     protected void scheduleRequest(@NonNull PendingRequest<S, I> pendingRequest) {
         cancelScheduledUnbind();
@@ -250,7 +272,7 @@ public abstract class AbstractRemoteService<S extends AbstractRemoteService<S, I
      * a simple {@link Runnable}.
      */
     protected void scheduleAsyncRequest(@NonNull AsyncRequest<I> request) {
-        cancelScheduledUnbind();
+        scheduleUnbind();
         // TODO(b/117779333): fix generics below
         @SuppressWarnings({"unchecked", "rawtypes"})
         final MyAsyncPendingRequest<S, I> asyncRequest = new MyAsyncPendingRequest(this, request);
@@ -263,12 +285,21 @@ public abstract class AbstractRemoteService<S extends AbstractRemoteService<S, I
     }
 
     protected void scheduleUnbind() {
+        final long unbindDelay = getTimeoutIdleBindMillis();
+
+        if (unbindDelay <= 0) {
+            if (mVerbose) Slog.v(mTag, "not scheduling unbind when value is " + unbindDelay);
+            return;
+        }
+
         cancelScheduledUnbind();
-        // TODO(b/111276913): implement "permanent binding"
         // TODO(b/117779333): make sure it's unbound if the service settings changing (right now
         // it's not)
+
+        mNextUnbind = SystemClock.elapsedRealtime() + unbindDelay;
+        if (mVerbose) Slog.v(mTag, "unbinding in " + unbindDelay + "ms: " + mNextUnbind);
         mHandler.sendMessageDelayed(obtainMessage(AbstractRemoteService::handleUnbind, this)
-                .setWhat(MSG_UNBIND), getTimeoutIdleBindMillis());
+                .setWhat(MSG_UNBIND), unbindDelay);
     }
 
     private void handleUnbind() {
@@ -342,6 +373,7 @@ public abstract class AbstractRemoteService<S extends AbstractRemoteService<S, I
                 mService = null;
             }
         }
+        mNextUnbind = 0;
         mContext.unbindService(mServiceConnection);
     }