Implement computer-to-device clipboard copy

It was already possible to _paste_ (with Ctrl+v) the content of the
computer clipboard on the device. Technically, it injects a sequence of
events to generate the text.

Add a new feature (Ctrl+Shift+v) to copy to the device clipboard
instead, without injecting the content. Contrary to events injection,
this preserves the UTF-8 content exactly, so the text is not broken by
special characters.

<https://github.com/Genymobile/scrcpy/issues/413>

README.md

@@ -289,6 +289,7 @@ you are interested, see [issue 14].
  | collapse notification panel            | `Ctrl`+`Shift`+`n`            |
  | copy device clipboard to computer      | `Ctrl`+`c`                    |
  | paste computer clipboard to device     | `Ctrl`+`v`                    |
+ | copy computer clipboard to device      | `Ctrl`+`Shift+`v`             |
  | enable/disable FPS counter (on stdout) | `Ctrl`+`i`                    |
 
 _¹Double-click on black borders to remove them._  

app/src/control_event.c

@@ -47,6 +47,12 @@ control_event_serialize(const struct control_event *event, unsigned char *buf) {
             buffer_write32be(&buf[13], (uint32_t) event->scroll_event.hscroll);
             buffer_write32be(&buf[17], (uint32_t) event->scroll_event.vscroll);
             return 21;
+        case CONTROL_EVENT_TYPE_SET_CLIPBOARD: {
+            size_t len = write_string(event->text_event.text,
+                                      CONTROL_EVENT_CLIPBOARD_TEXT_MAX_LENGTH,
+                                      &buf[1]);
+            return 1 + len;
+        }
         case CONTROL_EVENT_TYPE_BACK_OR_SCREEN_ON:
         case CONTROL_EVENT_TYPE_EXPAND_NOTIFICATION_PANEL:
         case CONTROL_EVENT_TYPE_COLLAPSE_NOTIFICATION_PANEL:
@@ -61,7 +67,15 @@ control_event_serialize(const struct control_event *event, unsigned char *buf) {
 
 void
 control_event_destroy(struct control_event *event) {
-    if (event->type == CONTROL_EVENT_TYPE_TEXT) {
-        SDL_free(event->text_event.text);
+    switch (event->type) {
+        case CONTROL_EVENT_TYPE_TEXT:
+            SDL_free(event->text_event.text);
+            break;
+        case CONTROL_EVENT_TYPE_SET_CLIPBOARD:
+            SDL_free(event->set_clipboard_event.text);
+            break;
+        default:
+            // do nothing
+            break;
     }
 }

app/src/control_event.h

@@ -10,7 +10,9 @@
 #include "common.h"
 
 #define CONTROL_EVENT_TEXT_MAX_LENGTH 300
-#define CONTROL_EVENT_SERIALIZED_MAX_SIZE (3 + CONTROL_EVENT_TEXT_MAX_LENGTH)
+#define CONTROL_EVENT_CLIPBOARD_TEXT_MAX_LENGTH 4093
+#define CONTROL_EVENT_SERIALIZED_MAX_SIZE \
+    (3 + CONTROL_EVENT_CLIPBOARD_TEXT_MAX_LENGTH)
 
 enum control_event_type {
     CONTROL_EVENT_TYPE_KEYCODE,
@@ -21,6 +23,7 @@ enum control_event_type {
     CONTROL_EVENT_TYPE_EXPAND_NOTIFICATION_PANEL,
     CONTROL_EVENT_TYPE_COLLAPSE_NOTIFICATION_PANEL,
     CONTROL_EVENT_TYPE_GET_CLIPBOARD,
+    CONTROL_EVENT_TYPE_SET_CLIPBOARD,
 };
 
 struct control_event {
@@ -44,6 +47,9 @@ struct control_event {
             int32_t hscroll;
             int32_t vscroll;
         } scroll_event;
+        struct {
+            char *text; // owned, to be freed by SDL_free()
+        } set_clipboard_event;
     };
 };
 

app/src/input_manager.c

@@ -136,6 +136,29 @@ request_device_clipboard(struct controller *controller) {
     }
 }
 
+static void
+set_device_clipboard(struct controller *controller) {
+    char *text = SDL_GetClipboardText();
+    if (!text) {
+        LOGW("Cannot get clipboard text: %s", SDL_GetError());
+        return;
+    }
+    if (!*text) {
+        // empty text
+        SDL_free(text);
+        return;
+    }
+
+    struct control_event control_event;
+    control_event.type = CONTROL_EVENT_TYPE_SET_CLIPBOARD;
+    control_event.set_clipboard_event.text = text;
+
+    if (!controller_push_event(controller, &control_event)) {
+        SDL_free(text);
+        LOGW("Cannot send clipboard paste event");
+    }
+}
+
 static void
 switch_fps_counter_state(struct video_buffer *vb) {
     mutex_lock(vb->mutex);
@@ -267,9 +290,15 @@ input_manager_process_key(struct input_manager *input_manager,
                 }
                 return;
             case SDLK_v:
-                if (control && ctrl && !meta && !shift && !repeat
+                if (control && ctrl && !meta && !repeat
                         && event->type == SDL_KEYDOWN) {
-                    clipboard_paste(input_manager->controller);
+                    if (shift) {
+                        // store the text in the device clipboard
+                        set_device_clipboard(input_manager->controller);
+                    } else {
+                        // inject the text as input events
+                        clipboard_paste(input_manager->controller);
+                    }
                 }
                 return;
             case SDLK_f:

app/src/main.c

@@ -143,6 +143,9 @@ static void usage(const char *arg0) {
         "    Ctrl+v\n"
         "        paste computer clipboard to device\n"
         "\n"
+        "    Ctrl+Shift+v\n"
+        "        copy computer clipboard to device\n"
+        "\n"
         "    Ctrl+i\n"
         "        enable/disable FPS counter (print frames/second in logs)\n"
         "\n"

app/tests/test_control_event_serialize.c

@@ -193,6 +193,26 @@ static void test_serialize_get_clipboard_event(void) {
     assert(!memcmp(buf, expected, sizeof(expected)));
 }
 
+static void test_serialize_set_clipboard_event(void) {
+    struct control_event event = {
+        .type = CONTROL_EVENT_TYPE_SET_CLIPBOARD,
+        .text_event = {
+            .text = "hello, world!",
+        },
+    };
+
+    unsigned char buf[CONTROL_EVENT_SERIALIZED_MAX_SIZE];
+    int size = control_event_serialize(&event, buf);
+    assert(size == 16);
+
+    const unsigned char expected[] = {
+        0x08, // CONTROL_EVENT_TYPE_SET_CLIPBOARD
+        0x00, 0x0d, // text length
+        'h', 'e', 'l', 'l', 'o', ',', ' ', 'w', 'o', 'r', 'l', 'd', '!', // text
+    };
+    assert(!memcmp(buf, expected, sizeof(expected)));
+}
+
 int main(void) {
     test_serialize_keycode_event();
     test_serialize_text_event();
@@ -203,5 +223,6 @@ int main(void) {
     test_serialize_expand_notification_panel_event();
     test_serialize_collapse_notification_panel_event();
     test_serialize_get_clipboard_event();
+    test_serialize_set_clipboard_event();
     return 0;
 }

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

@@ -13,6 +13,7 @@ public final class ControlEvent {
     public static final int TYPE_EXPAND_NOTIFICATION_PANEL = 5;
     public static final int TYPE_COLLAPSE_NOTIFICATION_PANEL = 6;
     public static final int TYPE_GET_CLIPBOARD = 7;
+    public static final int TYPE_SET_CLIPBOARD = 8;
 
     private int type;
     private String text;
@@ -61,6 +62,13 @@ public final class ControlEvent {
         return event;
     }
 
+    public static ControlEvent createSetClipboardControlEvent(String text) {
+        ControlEvent event = new ControlEvent();
+        event.type = TYPE_SET_CLIPBOARD;
+        event.text = text;
+        return event;
+    }
+
     public static ControlEvent createSimpleControlEvent(int type) {
         ControlEvent event = new ControlEvent();
         event.type = type;

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

@@ -13,11 +13,12 @@ public class ControlEventReader {
     private static final int SCROLL_PAYLOAD_LENGTH = 20;
 
     public static final int TEXT_MAX_LENGTH = 300;
+    public static final int CLIPBOARD_TEXT_MAX_LENGTH = 4093;
     private static final int RAW_BUFFER_SIZE = 1024;
 
     private final byte[] rawBuffer = new byte[RAW_BUFFER_SIZE];
     private final ByteBuffer buffer = ByteBuffer.wrap(rawBuffer);
-    private final byte[] textBuffer = new byte[TEXT_MAX_LENGTH];
+    private final byte[] textBuffer = new byte[CLIPBOARD_TEXT_MAX_LENGTH];
 
     public ControlEventReader() {
         // invariant: the buffer is always in "get" mode
@@ -63,6 +64,9 @@ public class ControlEventReader {
             case ControlEvent.TYPE_SCROLL:
                 controlEvent = parseScrollControlEvent();
                 break;
+            case ControlEvent.TYPE_SET_CLIPBOARD:
+                controlEvent = parseSetClipboardEvent();
+                break;
             case ControlEvent.TYPE_BACK_OR_SCREEN_ON:
             case ControlEvent.TYPE_EXPAND_NOTIFICATION_PANEL:
             case ControlEvent.TYPE_COLLAPSE_NOTIFICATION_PANEL:
@@ -132,6 +136,14 @@ public class ControlEventReader {
         return ControlEvent.createScrollControlEvent(position, hScroll, vScroll);
     }
 
+    private ControlEvent parseSetClipboardEvent() {
+        String text = parseString();
+        if (text == null) {
+            return null;
+        }
+        return ControlEvent.createSetClipboardControlEvent(text);
+    }
+
     private static Position readPosition(ByteBuffer buffer) {
         int x = buffer.getInt();
         int y = buffer.getInt();

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

@@ -147,6 +147,10 @@ public final class Device {
         return s.toString();
     }
 
+    public void setClipboardText(String text) {
+        serviceManager.getClipboardManager().setText(text);
+    }
+
     static Rect flipRect(Rect crop) {
         return new Rect(crop.top, crop.left, crop.bottom, crop.right);
     }

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

@@ -94,6 +94,9 @@ public class EventController {
                 String clipboardText = device.getClipboardText();
                 sender.pushClipboardText(clipboardText);
                 break;
+            case ControlEvent.TYPE_SET_CLIPBOARD:
+                device.setClipboardText(controlEvent.getText());
+                break;
             default:
                 // do nothing
         }

server/src/main/java/com/genymobile/scrcpy/wrappers/ClipboardManager.java

@@ -9,11 +9,13 @@ import java.lang.reflect.Method;
 public class ClipboardManager {
     private final IInterface manager;
     private final Method getPrimaryClipMethod;
+    private final Method setPrimaryClipMethod;
 
     public ClipboardManager(IInterface manager) {
         this.manager = manager;
         try {
             getPrimaryClipMethod = manager.getClass().getMethod("getPrimaryClip", String.class);
+            setPrimaryClipMethod = manager.getClass().getMethod("setPrimaryClip", ClipData.class, String.class);
         } catch (NoSuchMethodException e) {
             throw new AssertionError(e);
         }
@@ -30,4 +32,13 @@ public class ClipboardManager {
             throw new AssertionError(e);
         }
     }
+
+    public void setText(CharSequence text) {
+        ClipData clipData = ClipData.newPlainText(null, text);
+        try {
+            setPrimaryClipMethod.invoke(manager, clipData, "com.android.shell");
+        } catch (InvocationTargetException | IllegalAccessException e) {
+            throw new AssertionError(e);
+        }
+    }
 }

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

@@ -190,6 +190,26 @@ public class ControlEventReaderTest {
         Assert.assertEquals(ControlEvent.TYPE_GET_CLIPBOARD, event.getType());
     }
 
+    @Test
+    public void testParseSetClipboardEvent() throws IOException {
+        ControlEventReader reader = new ControlEventReader();
+
+        ByteArrayOutputStream bos = new ByteArrayOutputStream();
+        DataOutputStream dos = new DataOutputStream(bos);
+        dos.writeByte(ControlEvent.TYPE_SET_CLIPBOARD);
+        byte[] text = "testé".getBytes(StandardCharsets.UTF_8);
+        dos.writeShort(text.length);
+        dos.write(text);
+
+        byte[] packet = bos.toByteArray();
+
+        reader.readFrom(new ByteArrayInputStream(packet));
+        ControlEvent event = reader.next();
+
+        Assert.assertEquals(ControlEvent.TYPE_SET_CLIPBOARD, event.getType());
+        Assert.assertEquals("testé", event.getText());
+    }
+
     @Test
     public void testMultiEvents() throws IOException {
         ControlEventReader reader = new ControlEventReader();