Paste on "set clipboard" if possible

Ctrl+Shift+v synchronizes the computer clipboard to the Android device
clipboard. This feature had been added to provide a way to copy UTF-8
text from the computer to the device.

To make such a paste more straightforward, if the device runs at least
Android 7, also send a PASTE keycode to paste immediately.

<https://developer.android.com/reference/android/view/KeyEvent.html#KEYCODE_PASTE>

Fixes #786 <https://github.com/Genymobile/scrcpy/issues/786>

README.md

@@ -494,7 +494,8 @@ It is possible to synchronize clipboards between the computer and the device, in
 both directions:
 
  - `Ctrl`+`c` copies the device clipboard to the computer clipboard;
- - `Ctrl`+`Shift`+`v` copies the computer clipboard to the device clipboard;
+ - `Ctrl`+`Shift`+`v` copies the computer clipboard to the device clipboard (and
+   pastes if the device runs Android >= 7);
  - `Ctrl`+`v` _pastes_ the computer clipboard as a sequence of text events (but
    breaks non-ASCII characters).
 
@@ -560,7 +561,7 @@ Also see [issue #14].
 ## Shortcuts
 
  | Action                                      |   Shortcut                    |   Shortcut (macOS)
- | -------------------------------------- |:----------------------------- |:-----------------------------
+ | ------------------------------------------- |:----------------------------- |:-----------------------------
  | Switch fullscreen mode                      | `Ctrl`+`f`                    | `Cmd`+`f`
  | Rotate display left                         | `Ctrl`+`←` _(left)_           | `Cmd`+`←` _(left)_
  | Rotate display right                        | `Ctrl`+`→` _(right)_          | `Cmd`+`→` _(right)_
@@ -574,13 +575,13 @@ Also see [issue #14].
  | Click on `VOLUME_DOWN`                      | `Ctrl`+`↓` _(down)_           | `Cmd`+`↓` _(down)_
  | Click on `POWER`                            | `Ctrl`+`p`                    | `Cmd`+`p`
  | Power on                                    | _Right-click²_                | _Right-click²_
- | Turn device screen off (keep mirroring)| `Ctrl`+`o`                    | `Cmd`+`o`
+ | Turn device screen off (keep mirroring)     | `Ctrl`+`o`                    | `Cmd`+`o`
  | Rotate device screen                        | `Ctrl`+`r`                    | `Cmd`+`r`
  | Expand notification panel                   | `Ctrl`+`n`                    | `Cmd`+`n`
  | Collapse notification panel                 | `Ctrl`+`Shift`+`n`            | `Cmd`+`Shift`+`n`
  | Copy device clipboard to computer           | `Ctrl`+`c`                    | `Cmd`+`c`
  | Paste computer clipboard to device          | `Ctrl`+`v`                    | `Cmd`+`v`
- | Copy computer clipboard to device      | `Ctrl`+`Shift`+`v`            | `Cmd`+`Shift`+`v`
+ | Copy computer clipboard to device and paste | `Ctrl`+`Shift`+`v`            | `Cmd`+`Shift`+`v`
  | Enable/disable FPS counter (on stdout)      | `Ctrl`+`i`                    | `Cmd`+`i`
 
 _¹Double-click on black borders to remove them._  

app/scrcpy.1

@@ -280,7 +280,7 @@ Paste computer clipboard to device
 
 .TP
 .B Ctrl+Shift+v
-Copy computer clipboard to device
+Copy computer clipboard to device (and paste if the device runs Android >= 7)
 
 .TP
 .B Ctrl+i

app/src/cli.c

@@ -247,7 +247,8 @@ scrcpy_print_usage(const char *arg0) {
         "        Paste computer clipboard to device\n"
         "\n"
         "    " CTRL_OR_CMD "+Shift+v\n"
-        "        Copy computer clipboard to device\n"
+        "        Copy computer clipboard to device (and paste if the device\n"
+        "        runs Android >= 7)\n"
         "\n"
         "    " CTRL_OR_CMD "+i\n"
         "        Enable/disable FPS counter (print frames/second in logs)\n"

app/src/control_msg.c

@@ -67,10 +67,11 @@ control_msg_serialize(const struct control_msg *msg, unsigned char *buf) {
                              (uint32_t) msg->inject_scroll_event.vscroll);
             return 21;
         case CONTROL_MSG_TYPE_SET_CLIPBOARD: {
+            buf[1] = !!msg->set_clipboard.paste;
             size_t len = write_string(msg->set_clipboard.text,
                                       CONTROL_MSG_CLIPBOARD_TEXT_MAX_LENGTH,
-                                      &buf[1]);
+                                      &buf[2]);
-            return 1 + len;
+            return 2 + len;
         }
         case CONTROL_MSG_TYPE_SET_SCREEN_POWER_MODE:
             buf[1] = msg->set_screen_power_mode.mode;

app/src/control_msg.h

@@ -11,9 +11,9 @@
 #include "common.h"
 
 #define CONTROL_MSG_INJECT_TEXT_MAX_LENGTH 300
-#define CONTROL_MSG_CLIPBOARD_TEXT_MAX_LENGTH 4093
+#define CONTROL_MSG_CLIPBOARD_TEXT_MAX_LENGTH 4092
 #define CONTROL_MSG_SERIALIZED_MAX_SIZE \
-    (3 + CONTROL_MSG_CLIPBOARD_TEXT_MAX_LENGTH)
+    (4 + CONTROL_MSG_CLIPBOARD_TEXT_MAX_LENGTH)
 
 #define POINTER_ID_MOUSE UINT64_C(-1);
 
@@ -62,6 +62,7 @@ struct control_msg {
         } inject_scroll_event;
         struct {
             char *text; // owned, to be freed by SDL_free()
+            bool paste;
         } set_clipboard;
         struct {
             enum screen_power_mode mode;

app/src/input_manager.c

@@ -112,7 +112,7 @@ request_device_clipboard(struct controller *controller) {
 }
 
 static void
-set_device_clipboard(struct controller *controller) {
+set_device_clipboard(struct controller *controller, bool paste) {
     char *text = SDL_GetClipboardText();
     if (!text) {
         LOGW("Could not get clipboard text: %s", SDL_GetError());
@@ -127,6 +127,7 @@ set_device_clipboard(struct controller *controller) {
     struct control_msg msg;
     msg.type = CONTROL_MSG_TYPE_SET_CLIPBOARD;
     msg.set_clipboard.text = text;
+    msg.set_clipboard.paste = paste;
 
     if (!controller_push_msg(controller, &msg)) {
         SDL_free(text);
@@ -354,8 +355,8 @@ input_manager_process_key(struct input_manager *im,
             case SDLK_v:
                 if (control && cmd && !repeat && down) {
                     if (shift) {
-                        // store the text in the device clipboard
+                        // store the text in the device clipboard and paste
-                        set_device_clipboard(controller);
+                        set_device_clipboard(controller, true);
                     } else {
                         // inject the text as input events
                         clipboard_paste(controller);

app/tests/test_control_msg_serialize.c

@@ -201,16 +201,18 @@ static void test_serialize_set_clipboard(void) {
     struct control_msg msg = {
         .type = CONTROL_MSG_TYPE_SET_CLIPBOARD,
         .set_clipboard = {
+            .paste = true,
             .text = "hello, world!",
         },
     };
 
     unsigned char buf[CONTROL_MSG_SERIALIZED_MAX_SIZE];
     int size = control_msg_serialize(&msg, buf);
-    assert(size == 16);
+    assert(size == 17);
 
     const unsigned char expected[] = {
         CONTROL_MSG_TYPE_SET_CLIPBOARD,
+        1, // paste
         0x00, 0x0d, // text length
         'h', 'e', 'l', 'l', 'o', ',', ' ', 'w', 'o', 'r', 'l', 'd', '!', // text
     };

server/src/main/java/com/genymobile/scrcpy/ControlMessage.java

@@ -17,6 +17,8 @@ public final class ControlMessage {
     public static final int TYPE_SET_SCREEN_POWER_MODE = 9;
     public static final int TYPE_ROTATE_DEVICE = 10;
 
+    public static final int FLAGS_PASTE = 1;
+
     private int type;
     private String text;
     private int metaState; // KeyEvent.META_*
@@ -28,6 +30,7 @@ public final class ControlMessage {
     private Position position;
     private int hScroll;
     private int vScroll;
+    private int flags;
 
     private ControlMessage() {
     }
@@ -68,10 +71,13 @@ public final class ControlMessage {
         return msg;
     }
 
-    public static ControlMessage createSetClipboard(String text) {
+    public static ControlMessage createSetClipboard(String text, boolean paste) {
         ControlMessage msg = new ControlMessage();
         msg.type = TYPE_SET_CLIPBOARD;
         msg.text = text;
+        if (paste) {
+            msg.flags = FLAGS_PASTE;
+        }
         return msg;
     }
 
@@ -134,4 +140,8 @@ public final class ControlMessage {
     public int getVScroll() {
         return vScroll;
     }
+
+    public int getFlags() {
+        return flags;
+    }
 }

server/src/main/java/com/genymobile/scrcpy/ControlMessageReader.java

@@ -12,8 +12,9 @@ public class ControlMessageReader {
     static final int INJECT_TOUCH_EVENT_PAYLOAD_LENGTH = 27;
     static final int INJECT_SCROLL_EVENT_PAYLOAD_LENGTH = 20;
     static final int SET_SCREEN_POWER_MODE_PAYLOAD_LENGTH = 1;
+    static final int SET_CLIPBOARD_FIXED_PAYLOAD_LENGTH = 1;
 
-    public static final int CLIPBOARD_TEXT_MAX_LENGTH = 4093;
+    public static final int CLIPBOARD_TEXT_MAX_LENGTH = 4092; // 4096 - 1 (type) - 1 (parse flag) - 2 (length)
     public static final int INJECT_TEXT_MAX_LENGTH = 300;
 
     private static final int RAW_BUFFER_SIZE = 4096;
@@ -148,11 +149,15 @@ public class ControlMessageReader {
     }
 
     private ControlMessage parseSetClipboard() {
+        if (buffer.remaining() < SET_CLIPBOARD_FIXED_PAYLOAD_LENGTH) {
+            return null;
+        }
+        boolean parse = buffer.get() != 0;
         String text = parseString();
         if (text == null) {
             return null;
         }
-        return ControlMessage.createSetClipboard(text);
+        return ControlMessage.createSetClipboard(text, parse);
     }
 
     private ControlMessage parseSetScreenPowerMode() {

server/src/main/java/com/genymobile/scrcpy/Controller.java

@@ -1,5 +1,6 @@
 package com.genymobile.scrcpy;
 
+import android.os.Build;
 import android.os.SystemClock;
 import android.view.InputDevice;
 import android.view.KeyCharacterMap;
@@ -107,10 +108,8 @@ public class Controller {
                 sender.pushClipboardText(clipboardText);
                 break;
             case ControlMessage.TYPE_SET_CLIPBOARD:
-                boolean setClipboardOk = device.setClipboardText(msg.getText());
+                boolean paste = (msg.getFlags() & ControlMessage.FLAGS_PASTE) != 0;
-                if (setClipboardOk) {
+                setClipboard(msg.getText(), paste);
-                    Ln.i("Device clipboard set");
-                }
                 break;
             case ControlMessage.TYPE_SET_SCREEN_POWER_MODE:
                 if (device.supportsInputEvents()) {
@@ -227,4 +226,18 @@ public class Controller {
         int keycode = device.isScreenOn() ? KeyEvent.KEYCODE_BACK : KeyEvent.KEYCODE_POWER;
         return device.injectKeycode(keycode);
     }
+
+    private boolean setClipboard(String text, boolean paste) {
+        boolean ok = device.setClipboardText(text);
+        if (ok) {
+            Ln.i("Device clipboard set");
+        }
+
+        // On Android >= 7, also press the PASTE key if requested
+        if (paste && Build.VERSION.SDK_INT >= Build.VERSION_CODES.N && device.supportsInputEvents()) {
+            device.injectKeycode(KeyEvent.KEYCODE_PASTE);
+        }
+
+        return ok;
+    }
 }

server/src/test/java/com/genymobile/scrcpy/ControlMessageReaderTest.java

@@ -216,6 +216,7 @@ public class ControlMessageReaderTest {
         ByteArrayOutputStream bos = new ByteArrayOutputStream();
         DataOutputStream dos = new DataOutputStream(bos);
         dos.writeByte(ControlMessage.TYPE_SET_CLIPBOARD);
+        dos.writeByte(1); // paste
         byte[] text = "testé".getBytes(StandardCharsets.UTF_8);
         dos.writeShort(text.length);
         dos.write(text);
@@ -227,6 +228,9 @@ public class ControlMessageReaderTest {
 
         Assert.assertEquals(ControlMessage.TYPE_SET_CLIPBOARD, event.getType());
         Assert.assertEquals("testé", event.getText());
+
+        boolean parse = (event.getFlags() & ControlMessage.FLAGS_PASTE) != 0;
+        Assert.assertTrue(parse);
     }
 
     @Test
@@ -238,6 +242,7 @@ public class ControlMessageReaderTest {
         dos.writeByte(ControlMessage.TYPE_SET_CLIPBOARD);
 
         byte[] rawText = new byte[ControlMessageReader.CLIPBOARD_TEXT_MAX_LENGTH];
+        dos.writeByte(1); // paste
         Arrays.fill(rawText, (byte) 'a');
         String text = new String(rawText, 0, rawText.length);
 
@@ -251,6 +256,9 @@ public class ControlMessageReaderTest {
 
         Assert.assertEquals(ControlMessage.TYPE_SET_CLIPBOARD, event.getType());
         Assert.assertEquals(text, event.getText());
+
+        boolean parse = (event.getFlags() & ControlMessage.FLAGS_PASTE) != 0;
+        Assert.assertTrue(parse);
     }
 
     @Test