[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/Wayland/input_event.c

@@ -0,0 +1,179 @@
+/**
+ * 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 <linux/input.h>
+#include <string.h>
+
+static const double WL_SCROLL_STEP      = 15.0;
+static const double WL_HALF_SCROLL_STEP = 7.5;
+
+void wlInputInit(WaylandInput * input, const LG_DSInputSink * sink,
+    void * opaque)
+{
+  memset(input, 0, sizeof(*input));
+  input->sink   = sink;
+  input->opaque = opaque;
+}
+
+bool wlInputPointerEnter(WaylandInput * input, bool mainSurface)
+{
+  if (!mainSurface)
+    return false;
+
+  input->pointerInSurface = true;
+  input->sink->enter(input->opaque, true);
+  return true;
+}
+
+bool wlInputPointerLeave(WaylandInput * input, bool mainSurface)
+{
+  if (!mainSurface)
+    return false;
+
+  input->pointerInSurface = false;
+  input->sink->enter(input->opaque, false);
+  return true;
+}
+
+void wlInputPointerDisconnect(WaylandInput * input, bool notify)
+{
+  input->pointerInSurface = false;
+  if (notify)
+    input->sink->enter(input->opaque, false);
+}
+
+void wlInputPointerMotion(WaylandInput * input, double x, double y)
+{
+  input->sink->position(input->opaque, x, y);
+}
+
+static unsigned int mapButton(uint32_t button)
+{
+  switch (button)
+  {
+    case BTN_LEFT:
+      return 1;
+    case BTN_MIDDLE:
+      return 2;
+    case BTN_RIGHT:
+      return 3;
+    case BTN_SIDE:
+      return 6;
+    case BTN_EXTRA:
+      return 7;
+    case BTN_FORWARD:
+      return 8;
+    case BTN_BACK:
+      return 9;
+    case BTN_TASK:
+      return 10;
+  }
+
+  return 0;
+}
+
+void wlInputPointerButton(WaylandInput * input, uint32_t button,
+    bool pressed)
+{
+  const unsigned int mapped = mapButton(button);
+  if (mapped)
+    input->sink->button(input->opaque, mapped, pressed);
+}
+
+void wlInputPointerAxis(WaylandInput * input, bool vertical, double delta)
+{
+  if (!vertical)
+    return;
+
+  input->scrollState += delta;
+
+  while (input->scrollState > WL_HALF_SCROLL_STEP)
+  {
+    input->sink->button(input->opaque, 5, true);
+    input->sink->button(input->opaque, 5, false);
+    input->scrollState -= WL_SCROLL_STEP;
+  }
+
+  while (input->scrollState < -WL_HALF_SCROLL_STEP)
+  {
+    input->sink->button(input->opaque, 4, true);
+    input->sink->button(input->opaque, 4, false);
+    input->scrollState += WL_SCROLL_STEP;
+  }
+
+  input->sink->wheel(input->opaque, delta / WL_SCROLL_STEP);
+}
+
+void wlInputRelativeMotion(WaylandInput * input, bool active,
+    double x, double y, double rawX, double rawY)
+{
+  if (active)
+    input->sink->relative(input->opaque, x, y, rawX, rawY);
+}
+
+void wlInputRealignPointer(WaylandInput * input, double x, double y)
+{
+  if (input->pointerInSurface)
+    input->sink->position(input->opaque, x, y);
+}
+
+bool wlInputKeyboardEnter(WaylandInput * input, bool mainSurface,
+    const uint32_t * keys, size_t count)
+{
+  if (!mainSurface)
+    return false;
+
+  input->focused = true;
+  input->sink->focus(input->opaque, true);
+  for (size_t i = 0; i < count; ++i)
+    input->sink->key(input->opaque, keys[i], true);
+  return true;
+}
+
+bool wlInputKeyboardLeave(WaylandInput * input, bool mainSurface)
+{
+  if (!mainSurface)
+    return false;
+
+  input->focused = false;
+  input->sink->focus(input->opaque, false);
+  return true;
+}
+
+void wlInputKeyboardKey(WaylandInput * input, uint32_t key, bool pressed,
+    const char * text)
+{
+  if (!input->focused)
+    return;
+
+  input->sink->key(input->opaque, key, pressed);
+  if (pressed && text && *text)
+    input->sink->text(input->opaque, text);
+}
+
+void wlInputKeyboardState(WaylandInput * input,
+    bool ctrl, bool shift, bool alt, bool super,
+    bool numLock, bool capsLock, bool scrollLock)
+{
+  input->sink->modifiers(input->opaque, ctrl, shift, alt, super);
+  input->sink->leds(input->opaque, numLock, capsLock, scrollLock);
+}