[client] input: add display server behaviour tests

Extract input policy from the Wayland and X11 protocol handlers.

Exercise both implementations against literal Wayland event traces.

client/displayservers/X11/input_event.c

@@ -0,0 +1,183 @@
+/**
+ * Looking Glass
+ * Copyright © 2017-2026 The Looking Glass Authors
+ * https://looking-glass.io
+ *
+ * This program is free software; you can redistribute it and/or modify it
+ * under the terms of the GNU General Public License as published by the Free
+ * Software Foundation; either version 2 of the License, or (at your option)
+ * any later version.
+ *
+ * This program is distributed in the hope that it will be useful, but WITHOUT
+ * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
+ * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License for
+ * more details.
+ *
+ * You should have received a copy of the GNU General Public License along
+ * with this program; if not, write to the Free Software Foundation, Inc., 59
+ * Temple Place, Suite 330, Boston, MA 02111-1307 USA
+ */
+
+#include "input_event.h"
+
+#include <string.h>
+
+static unsigned int mapButton(unsigned int button)
+{
+  if (button >= 1 && button <= 5)
+    return button;
+
+  /* X11 reserves buttons 6 and 7 for horizontal scrolling. */
+  if (button >= 8 && button < 34)
+    return button - 2;
+
+  return 0;
+}
+
+void x11InputInit(X11Input * input, const LG_DSInputSink * sink,
+    void * opaque)
+{
+  memset(input, 0, sizeof(*input));
+  input->sink   = sink;
+  input->opaque = opaque;
+}
+
+bool x11InputFocus(X11Input * input, bool focused, double x, double y,
+    const uint32_t * keys, size_t count)
+{
+  (void)keys;
+  (void)count;
+
+  if (input->focused == focused)
+    return false;
+
+  input->focused = focused;
+  input->sink->position(input->opaque, x, y);
+  input->sink->focus(input->opaque, focused);
+  return true;
+}
+
+bool x11InputPointerEnter(X11Input * input, bool mainWindow,
+    bool normal, double x, double y)
+{
+  if (input->entered || !mainWindow || !normal)
+    return false;
+
+  input->sink->position(input->opaque, x, y);
+  input->sink->enter(input->opaque, true);
+  input->entered = true;
+  return true;
+}
+
+bool x11InputPointerLeave(X11Input * input, bool mainWindow,
+    bool normal, bool captureMode, double x, double y)
+{
+  if (!input->entered || !mainWindow || input->buttons || captureMode ||
+      !normal)
+    return false;
+
+  input->sink->position(input->opaque, x, y);
+  input->sink->enter(input->opaque, false);
+  input->entered = false;
+  return true;
+}
+
+void x11InputPointerMotion(X11Input * input, double x, double y,
+    bool pointerGrabbed)
+{
+  input->sink->position(input->opaque, x, y);
+
+  if (!pointerGrabbed)
+    input->sink->relative(input->opaque, 0.0, 0.0, 0.0, 0.0);
+}
+
+void x11InputPointerButton(X11Input * input, unsigned int detail,
+    bool pressed, bool raw, uint32_t time, bool inputActive)
+{
+  if (raw)
+  {
+    if (!inputActive)
+      return;
+  }
+  else if (!input->focused || !input->entered)
+    return;
+
+  const unsigned int button = mapButton(detail);
+  if (!button)
+    return;
+
+  if (!raw)
+  {
+    if (pressed && button == 4)
+      input->sink->wheel(input->opaque, -0.5);
+    else if (pressed && button == 5)
+      input->sink->wheel(input->opaque, 0.5);
+    else if (button != 4 && button != 5)
+      input->sink->button(input->opaque, button, pressed);
+    return;
+  }
+
+  uint32_t * previousTime = pressed ?
+    &input->previousPressTime : &input->previousReleaseTime;
+  uint32_t * previousButton = pressed ?
+    &input->previousPressButton : &input->previousReleaseButton;
+
+  if (time == *previousTime && detail == *previousButton)
+    return;
+
+  *previousTime   = time;
+  *previousButton = detail;
+
+  const uint32_t mask = UINT32_C(1) << button;
+  if (pressed)
+    input->buttons |= mask;
+  else
+    input->buttons &= ~mask;
+
+  input->sink->button(input->opaque, button, pressed);
+}
+
+void x11InputRelativeMotion(X11Input * input, uint32_t time,
+    double x, double y, double rawX, double rawY, bool inputActive)
+{
+  if (!inputActive)
+    return;
+
+  if (time == input->previousMotionTime &&
+      x == input->previousMotionX && y == input->previousMotionY)
+    return;
+
+  input->previousMotionTime = time;
+  input->previousMotionX    = x;
+  input->previousMotionY    = y;
+
+  input->sink->relative(input->opaque, x, y, rawX, rawY);
+}
+
+void x11InputKeyboardKey(X11Input * input, unsigned int keycode,
+    int minKeycode, bool pressed, bool raw, bool inputActive,
+    const char * text)
+{
+  if (raw)
+  {
+    if (!inputActive)
+      return;
+  }
+  else if (!input->focused)
+    return;
+
+  input->sink->key(input->opaque, (int)keycode - minKeycode, pressed);
+
+  if (!raw && pressed && text)
+    input->sink->text(input->opaque, text);
+}
+
+void x11InputKeyboardState(X11Input * input,
+    bool ctrl, bool shift, bool alt, bool super,
+    bool numLock, bool capsLock, bool scrollLock)
+{
+  (void)numLock;
+  (void)capsLock;
+  (void)scrollLock;
+  input->sink->modifiers(input->opaque, ctrl, shift, alt, super);
+}