Implement plain text clipboard sharing from VM to Android

Bug: 349702327
Test: Run Ferrochrome, copy text in Ferrochrome, and paste text in
Android

Change-Id: I2b5a4050c3994708d71910564deadb610e4163ff
diff --git a/vmlauncher_app/java/com/android/virtualization/vmlauncher/MainActivity.java b/vmlauncher_app/java/com/android/virtualization/vmlauncher/MainActivity.java
index a3ecae7..258aeea 100644
--- a/vmlauncher_app/java/com/android/virtualization/vmlauncher/MainActivity.java
+++ b/vmlauncher_app/java/com/android/virtualization/vmlauncher/MainActivity.java
@@ -17,6 +17,7 @@
 package com.android.virtualization.vmlauncher;
 
 import static android.content.pm.PackageManager.PERMISSION_GRANTED;
+import static android.os.ParcelFileDescriptor.AutoCloseInputStream;
 import static android.os.ParcelFileDescriptor.AutoCloseOutputStream;
 import static android.system.virtualmachine.VirtualMachineConfig.CPU_TOPOLOGY_MATCH_HOST;
 
@@ -68,6 +69,7 @@
 import java.io.OutputStream;
 import java.nio.ByteBuffer;
 import java.nio.ByteOrder;
+import java.nio.charset.StandardCharsets;
 import java.nio.file.Files;
 import java.nio.file.Path;
 import java.util.ArrayList;
@@ -464,10 +466,8 @@
     }
 
     private static final int CLIPBOARD_SHARING_SERVER_PORT = 3580;
-    // TODO(349702313): Introduce READ_CLIPBOARD_FROM_VM as 0 for reading clipboard from
-    // VM.
-    // TODO(349702313): Introduce WRITE_CLIPBOARD_TYPE_EMPTY as 1 for receiving empty clipboard data
-    // from VM.
+    private static final byte READ_CLIPBOARD_FROM_VM = 0;
+    private static final byte WRITE_CLIPBOARD_TYPE_EMPTY = 1;
     private static final byte WRITE_CLIPBOARD_TYPE_TEXT_PLAIN = 2;
 
     private ClipboardManager getClipboardManager() {
@@ -533,6 +533,49 @@
         }
     }
 
+    private boolean readClipboardFromVm() {
+        ByteBuffer request = constructClipboardHeader(READ_CLIPBOARD_FROM_VM, 0);
+
+        ParcelFileDescriptor pfd = connectClipboardSharingServer();
+        if (pfd == null) {
+            Log.d(TAG, "file descriptor of ClipboardSharingServer is null");
+            return false;
+        }
+        OutputStream output = new AutoCloseOutputStream(pfd);
+        try {
+            output.write(request.array());
+            output.flush();
+            Log.d(TAG, "successfully send request to the VM for reading clipboard");
+        } catch (IOException e) {
+            Log.e(TAG, "failed to send request to the VM for read clipboard", e);
+            return false;
+        }
+
+        InputStream input = new AutoCloseInputStream(pfd);
+        try {
+            ByteBuffer header = ByteBuffer.wrap(input.readNBytes(8));
+            header.order(ByteOrder.LITTLE_ENDIAN);
+            switch (header.get(0)) {
+                case WRITE_CLIPBOARD_TYPE_EMPTY:
+                    Log.d(TAG, "clipboard data in VM is empty");
+                    return true;
+                case WRITE_CLIPBOARD_TYPE_TEXT_PLAIN:
+                    int dataSize = header.getInt(4);
+                    String text_data =
+                            new String(input.readNBytes(dataSize), StandardCharsets.UTF_8);
+                    getClipboardManager().setPrimaryClip(ClipData.newPlainText(null, text_data));
+                    Log.d(TAG, "successfully received clipboard data from VM");
+                    return true;
+                default:
+                    Log.e(TAG, "unknown clipboard response type");
+                    return false;
+            }
+        } catch (IOException e) {
+            Log.e(TAG, "failed to receive clipboard content from the VM", e);
+            return false;
+        }
+    }
+
     @Override
     public void onWindowFocusChanged(boolean hasFocus) {
         super.onWindowFocusChanged(hasFocus);
@@ -545,6 +588,9 @@
             if (hasFocus) {
                 Log.d(TAG, "writing clipboard of host device into VM");
                 writeClipboardToVm();
+            } else {
+                Log.d(TAG, "reading clipboard of VM");
+                readClipboardFromVm();
             }
         }
     }