UsbService: Refactor enableUsbData() for multiple disable requesters

Track parties requesting USB data signal disabling. Add UIDs to mUsbDisableRequesters on disable requests, remove on enable requests. Preserve existing USB data update behavior.

Bug: 287498482
Test: manual testing
Change-Id: I7629e60978f3e4acbad98602f31239f134cb4ed4

core/java/android/hardware/usb/flags/system_sw_usb_flags.aconfig

@@ -20,3 +20,10 @@ flag {
     description: "Enable reporting USB data compliance warnings from HAL when set"
     bug: "296119135"
 }
+
+flag {
+    name: "enable_usb_data_signal_staking"
+    namespace: "preload_safety"
+    description: "Enables signal API with staking"
+    bug: "296119135"
+}
\ No newline at end of file

services/usb/java/com/android/server/usb/UsbService.java

@@ -53,6 +53,7 @@ import android.os.RemoteException;
 import android.os.UserHandle;
 import android.os.UserManager;
 import android.service.usb.UsbServiceDumpProto;
+import android.util.ArrayMap;
 import android.util.ArraySet;
 import android.util.Slog;
 import android.util.proto.ProtoOutputStream;
@@ -156,6 +157,10 @@ public class UsbService extends IUsbManager.Stub {
 
     private final Object mLock = new Object();
 
+    // Key: USB port id
+    // Value: A set of UIDs of requesters who request disabling usb data
+    private final ArrayMap<String, ArraySet<Integer>> mUsbDisableRequesters = new ArrayMap<>();
+
     /**
      * @return the {@link UsbUserSettingsManager} for the given userId
      */
@@ -859,6 +864,11 @@ public class UsbService extends IUsbManager.Stub {
         Objects.requireNonNull(callback, "enableUsbData: callback must not be null. opId:"
                 + operationId);
         mContext.enforceCallingOrSelfPermission(android.Manifest.permission.MANAGE_USB, null);
+
+        if (android.hardware.usb.flags.Flags.enableUsbDataSignalStaking()) {
+            if (!shouldUpdateUsbSignaling(portId, enable, Binder.getCallingUid())) return false;
+        }
+
         final long ident = Binder.clearCallingIdentity();
         boolean wait;
         try {
@@ -878,6 +888,31 @@ public class UsbService extends IUsbManager.Stub {
         return wait;
     }
 
+    /**
+     * If enable = true, exclude UID from update list.
+     * If enable = false, include UID in update list.
+     * Return false if enable = true and the list is empty (no updates).
+     * Return true otherwise (let downstream decide on updates).
+     */
+    private boolean shouldUpdateUsbSignaling(String portId, boolean enable, int uid) {
+        synchronized (mUsbDisableRequesters) {
+            if (!mUsbDisableRequesters.containsKey(portId)) {
+                mUsbDisableRequesters.put(portId, new ArraySet<>());
+            }
+
+            ArraySet<Integer> uidsOfDisableRequesters = mUsbDisableRequesters.get(portId);
+
+            if (enable) {
+                uidsOfDisableRequesters.remove(uid);
+                // re-enable USB port (return true) if there are no other disable requesters
+                return uidsOfDisableRequesters.isEmpty();
+            } else {
+                uidsOfDisableRequesters.add(uid);
+            }
+        }
+        return true;
+    }
+
     @Override
     public void enableUsbDataWhileDocked(String portId, int operationId,
             IUsbOperationInternal callback) {