refactor: adopt vterm

We have changed too much to consider it a mere bundled dependency (such
as unicode handling in e3bfcf2fd4), and
can consider it our own at this point.

src/nvim/vterm/mouse.c

@@ -0,0 +1,113 @@
+#include "nvim/tui/termkey/termkey.h"
+#include "nvim/vterm/mouse.h"
+#include "nvim/vterm/vterm.h"
+#include "nvim/vterm/vterm_internal_defs.h"
+
+#ifdef INCLUDE_GENERATED_DECLARATIONS
+# include "vterm/mouse.c.generated.h"
+#endif
+
+static void output_mouse(VTermState *state, int code, int pressed, int modifiers, int col, int row)
+{
+  modifiers <<= 2;
+
+  switch (state->mouse_protocol) {
+  case MOUSE_X10:
+    if (col + 0x21 > 0xff) {
+      col = 0xff - 0x21;
+    }
+    if (row + 0x21 > 0xff) {
+      row = 0xff - 0x21;
+    }
+
+    if (!pressed) {
+      code = 3;
+    }
+
+    vterm_push_output_sprintf_ctrl(state->vt, C1_CSI, "M%c%c%c",
+                                   (code | modifiers) + 0x20, col + 0x21, row + 0x21);
+    break;
+
+  case MOUSE_UTF8: {
+    char utf8[18];
+    size_t len = 0;
+
+    if (!pressed) {
+      code = 3;
+    }
+
+    len += (size_t)fill_utf8((code | modifiers) + 0x20, utf8 + len);
+    len += (size_t)fill_utf8(col + 0x21, utf8 + len);
+    len += (size_t)fill_utf8(row + 0x21, utf8 + len);
+    utf8[len] = 0;
+
+    vterm_push_output_sprintf_ctrl(state->vt, C1_CSI, "M%s", utf8);
+  }
+  break;
+
+  case MOUSE_SGR:
+    vterm_push_output_sprintf_ctrl(state->vt, C1_CSI, "<%d;%d;%d%c",
+                                   code | modifiers, col + 1, row + 1, pressed ? 'M' : 'm');
+    break;
+
+  case MOUSE_RXVT:
+    if (!pressed) {
+      code = 3;
+    }
+
+    vterm_push_output_sprintf_ctrl(state->vt, C1_CSI, "%d;%d;%dM",
+                                   code | modifiers, col + 1, row + 1);
+    break;
+  }
+}
+
+void vterm_mouse_move(VTerm *vt, int row, int col, VTermModifier mod)
+{
+  VTermState *state = vt->state;
+
+  if (col == state->mouse_col && row == state->mouse_row) {
+    return;
+  }
+
+  state->mouse_col = col;
+  state->mouse_row = row;
+
+  if ((state->mouse_flags & MOUSE_WANT_DRAG && state->mouse_buttons)
+      || (state->mouse_flags & MOUSE_WANT_MOVE)) {
+    int button = state->mouse_buttons & 0x01 ? 1
+                                             : state->mouse_buttons & 0x02 ? 2
+                                                                           : state->mouse_buttons &
+                 0x04 ? 3 : 4;
+    output_mouse(state, button - 1 + 0x20, 1, (int)mod, col, row);
+  }
+}
+
+void vterm_mouse_button(VTerm *vt, int button, bool pressed, VTermModifier mod)
+{
+  VTermState *state = vt->state;
+
+  int old_buttons = state->mouse_buttons;
+
+  if (button > 0 && button <= 3) {
+    if (pressed) {
+      state->mouse_buttons |= (1 << (button - 1));
+    } else {
+      state->mouse_buttons &= ~(1 << (button - 1));
+    }
+  }
+
+  // Most of the time we don't get button releases from 4/5
+  if (state->mouse_buttons == old_buttons && button < 4) {
+    return;
+  }
+
+  if (!state->mouse_flags) {
+    return;
+  }
+
+  if (button < 4) {
+    output_mouse(state, button - 1, pressed, (int)mod, state->mouse_col, state->mouse_row);
+  } else if (button < 8) {
+    output_mouse(state, button - 4 + 0x40, pressed, (int)mod, state->mouse_col, state->mouse_row);
+  }
+}