Uinput: Add sync command to get a response when the command is processed

Bug: 291881033
Bug: 294275314
Test: manual
Change-Id: Ie522ff44aa1cb7ceb7f21a23d6dd68efd1845f7c
Merged-In: Ie522ff44aa1cb7ceb7f21a23d6dd68efd1845f7c

cmds/uinput/README.md

@@ -153,6 +153,38 @@ Example:
 }
 ```
 
+4. `sync`
+
+A command used to get a response once the command is processed. When several `inject` and `delay`
+commands are used in a row, the `sync` command can be used to track the progress of the command
+queue.
+
+|    Field    |  Type   | Description                                  |
+|:-----------:|:-------:|:---------------------------------------------|
+|    `id`     | integer | Device ID                                    |
+|  `command`  | string  | Must be set to "sync"                        |
+| `syncToken` | string  | The token used to identify this sync command |
+
+Example:
+
+```json5
+{
+  "id": 1,
+  "command": "syncToken",
+  "syncToken": "finished_injecting_events"
+}
+```
+
+This command will result in the following response when it is processed:
+
+```json5
+{
+  "id": 1,
+  "result": "sync",
+  "syncToken": "finished_injecting_events"
+}
+```
+
 ### Notes
 1. As soon as EOF is reached (either in interactive mode, or in file mode),
 the device that was created will be unregistered. There is no

cmds/uinput/src/com/android/commands/uinput/Device.java

@@ -45,6 +45,7 @@ public class Device {
     private static final int MSG_OPEN_UINPUT_DEVICE = 1;
     private static final int MSG_CLOSE_UINPUT_DEVICE = 2;
     private static final int MSG_INJECT_EVENT = 3;
+    private static final int MSG_SYNC_EVENT = 4;
 
     private final int mId;
     private final HandlerThread mThread;
@@ -118,6 +119,16 @@ public class Device {
         mTimeToSend = Math.max(SystemClock.uptimeMillis(), mTimeToSend) + delay;
     }
 
+    /**
+     * Synchronize the uinput command queue by writing a sync response with the provided syncToken
+     * to the output stream when this event is processed.
+     *
+     * @param syncToken  The token for this sync command.
+     */
+    public void syncEvent(String syncToken) {
+        mHandler.sendMessageAtTime(mHandler.obtainMessage(MSG_SYNC_EVENT, syncToken), mTimeToSend);
+    }
+
     /**
      * Close an uinput device.
      *
@@ -171,6 +182,9 @@ public class Device {
                         mCond.notify();
                     }
                     break;
+                case MSG_SYNC_EVENT:
+                    handleSyncEvent((String) msg.obj);
+                    break;
                 default:
                     throw new IllegalArgumentException("Unknown device message");
             }
@@ -184,6 +198,18 @@ public class Device {
             getLooper().myQueue().removeSyncBarrier(mBarrierToken);
             mBarrierToken = 0;
         }
+
+        private void handleSyncEvent(String syncToken) {
+            final JSONObject json = new JSONObject();
+            try {
+                json.put("reason", "sync");
+                json.put("id", mId);
+                json.put("syncToken", syncToken);
+            } catch (JSONException e) {
+                throw new RuntimeException("Could not create JSON object ", e);
+            }
+            writeOutputObject(json);
+        }
     }
 
     private class DeviceCallback {
@@ -211,7 +237,7 @@ public class Device {
         }
 
         public void onDeviceVibrating(int value) {
-            JSONObject json = new JSONObject();
+            final JSONObject json = new JSONObject();
             try {
                 json.put("reason", "vibrating");
                 json.put("id", mId);
@@ -219,12 +245,7 @@ public class Device {
             } catch (JSONException e) {
                 throw new RuntimeException("Could not create JSON object ", e);
             }
-            try {
-                mOutputStream.write(json.toString().getBytes());
-                mOutputStream.flush();
-            } catch (IOException e) {
-                throw new RuntimeException(e);
-            }
+            writeOutputObject(json);
         }
 
         public void onDeviceError() {
@@ -234,4 +255,13 @@ public class Device {
             msg.sendToTarget();
         }
     }
+
+    private void writeOutputObject(JSONObject json) {
+        try {
+            mOutputStream.write(json.toString().getBytes());
+            mOutputStream.flush();
+        } catch (IOException e) {
+            throw new RuntimeException(e);
+        }
+    }
 }

cmds/uinput/src/com/android/commands/uinput/Event.java

@@ -42,7 +42,8 @@ public class Event {
     enum Command {
         REGISTER("register"),
         DELAY("delay"),
-        INJECT("inject");
+        INJECT("inject"),
+        SYNC("sync");
 
         final String mCommandName;
 
@@ -77,6 +78,7 @@ public class Event {
     private int mFfEffectsMax = 0;
     private String mInputport;
     private SparseArray<InputAbsInfo> mAbsInfo;
+    private String mSyncToken;
 
     public int getId() {
         return mId;
@@ -126,6 +128,10 @@ public class Event {
         return mInputport;
     }
 
+    public String getSyncToken() {
+        return mSyncToken;
+    }
+
     /**
      * Convert an event to String.
      */
@@ -206,6 +212,10 @@ public class Event {
             mEvent.mInputport = port;
         }
 
+        public void setSyncToken(String syncToken) {
+            mEvent.mSyncToken = Objects.requireNonNull(syncToken, "Sync token must not be null");
+        }
+
         public Event build() {
             if (mEvent.mId == -1) {
                 throw new IllegalStateException("No event id");
@@ -225,10 +235,15 @@ public class Event {
                     }
                 }
                 case INJECT -> {
-                    if (mEvent.mInjections  == null) {
+                    if (mEvent.mInjections == null) {
                         throw new IllegalStateException("Inject command is missing injection data");
                     }
                 }
+                case SYNC -> {
+                    if (mEvent.mSyncToken == null) {
+                        throw new IllegalStateException("Sync command is missing sync token");
+                    }
+                }
             }
             return mEvent;
         }
@@ -295,6 +310,9 @@ public class Event {
                             case "port":
                                 eb.setInputport(mReader.nextString());
                                 break;
+                            case "syncToken":
+                                eb.setSyncToken(mReader.nextString());
+                                break;
                             default:
                                 mReader.skipValue();
                         }

cmds/uinput/src/com/android/commands/uinput/Uinput.java

@@ -112,6 +112,7 @@ public class Uinput {
                     error("Device id=" + e.getId() + " is already registered. Ignoring event.");
             case INJECT -> d.injectEvent(e.getInjections());
             case DELAY -> d.addDelay(e.getDuration());
+            case SYNC -> d.syncEvent(e.getSyncToken());
         }
     }