Remove scroll_margin parameter from window_get_scroll_margin()

The passed in value is always taken from `GlobalOptions::scroll_margin`,
so we may as well just access that via `Window::editor::options` from
within the function.

src/commands.c

@@ -267,8 +267,7 @@ static bool cmd_bolsf(EditorState *e, const CommandArgs *a)
     handle_selection_flags(view, a);
 
     if (!block_iter_bol(&view->cursor)) {
-        unsigned int margin = e->options.scroll_margin;
-        long top = view->vy + window_get_scroll_margin(e->window, margin);
+        long top = view->vy + window_get_scroll_margin(e->window);
         if (view->cy > top) {
             move_up(view, view->cy - top);
         } else {
@@ -695,7 +694,7 @@ static bool cmd_eolsf(EditorState *e, const CommandArgs *a)
 
     if (!block_iter_eol(&view->cursor)) {
         Window *window = e->window;
-        long margin = window_get_scroll_margin(window, e->options.scroll_margin);
+        long margin = window_get_scroll_margin(window);
         long bottom = view->vy + window->edit_h - 1 - margin;
         if (view->cy < bottom) {
             move_down(view, bottom - view->cy);
@@ -1341,7 +1340,7 @@ static bool cmd_pgdown(EditorState *e, const CommandArgs *a)
     handle_selection_flags(view, a);
 
     Window *window = e->window;
-    long margin = window_get_scroll_margin(window, e->options.scroll_margin);
+    long margin = window_get_scroll_margin(window);
     long bottom = view->vy + window->edit_h - 1 - margin;
     long count;
 
@@ -1361,7 +1360,7 @@ static bool cmd_pgup(EditorState *e, const CommandArgs *a)
     handle_selection_flags(view, a);
 
     Window *window = e->window;
-    long margin = window_get_scroll_margin(window, e->options.scroll_margin);
+    long margin = window_get_scroll_margin(window);
     long top = view->vy + margin;
     long count;
 

src/ui-window.c

@@ -77,10 +77,10 @@ static void update_window_full(Window *window, void* UNUSED_ARG(data))
     EditorState *e = window->editor;
     View *view = window->view;
     const GlobalOptions *options = &e->options;
-    view_update(view, options->scroll_margin);
-
     const StyleMap *styles = &e->styles;
     Terminal *term = &e->terminal;
+    view_update(view);
+
     if (options->tab_bar) {
         print_tabbar(term, styles, window);
     }
@@ -146,7 +146,7 @@ void update_buffer_windows (
             block_iter_goto_offset(&view->cursor, view->saved_cursor_offset);
 
             // This has already been done for the current view
-            view_update(view, options->scroll_margin);
+            view_update(view);
         }
         update_window(term, view->window, styles, options);
     }

src/ui.c

@@ -170,7 +170,7 @@ void update_screen(EditorState *e, const ScreenState *s)
     if (flags & UPDATE_ALL_WINDOWS) {
         update_all_windows(term, root_frame, styles);
     } else {
-        view_update(view, options->scroll_margin);
+        view_update(view);
         if (s->id == buffer->id) {
             if (s->vx != view->vx || s->vy != view->vy) {
                 mark_all_lines_changed(buffer);

src/view.c

@@ -93,10 +93,10 @@ static void view_update_vx(View *v)
     }
 }
 
-static void view_update_vy(View *v, unsigned int scroll_margin)
+static void view_update_vy(View *v)
 {
     Window *window = v->window;
-    int margin = window_get_scroll_margin(window, scroll_margin);
+    unsigned int margin = window_get_scroll_margin(window);
     long max_y = v->vy + window->edit_h - 1 - margin;
 
     if (v->cy < v->vy + margin) {
@@ -110,15 +110,15 @@ static void view_update_vy(View *v, unsigned int scroll_margin)
     }
 }
 
-void view_update(View *v, unsigned int scroll_margin)
+void view_update(View *v)
 {
     view_update_cursor_x(v);
     view_update_cursor_y(v);
     view_update_vx(v);
     if (v->force_center || (v->center_on_scroll && view_is_cursor_visible(v))) {
         view_center_to_cursor(v);
     } else {
-        view_update_vy(v, scroll_margin);
+        view_update_vy(v);
     }
     v->force_center = false;
     v->center_on_scroll = false;

src/view.h

@@ -59,7 +59,7 @@ static inline void view_reset_preferred_x(View *view)
 
 void view_update_cursor_y(View *view) NONNULL_ARGS;
 void view_update_cursor_x(View *view) NONNULL_ARGS;
-void view_update(View *view, unsigned int scroll_margin) NONNULL_ARGS;
+void view_update(View *view) NONNULL_ARGS;
 long view_get_preferred_x(View *view) NONNULL_ARGS;
 bool view_can_close(const View *view) NONNULL_ARGS;
 StringView view_get_word_under_cursor(const View *view) NONNULL_ARGS;

src/window.c

@@ -389,10 +389,15 @@ void window_set_size(Window *window, int w, int h)
     window_calculate_line_numbers(window);
 }
 
-int window_get_scroll_margin(const Window *window, unsigned int scroll_margin)
+unsigned int window_get_scroll_margin(const Window *window)
 {
-    int max = (window->edit_h - 1) / 2;
-    BUG_ON(max < 0);
+    int edit_h = window->edit_h;
+    if (unlikely(edit_h <= 2)) {
+        return 0;
+    }
+
+    unsigned int max = (edit_h - 1) / 2;
+    unsigned int scroll_margin = window->editor->options.scroll_margin;
     return MIN(max, scroll_margin);
 }
 

src/window.h

@@ -63,7 +63,7 @@ View *window_open_files(Window *window, char **filenames, const char *encoding)
 void window_calculate_line_numbers(Window *window) NONNULL_ARGS;
 void window_set_coordinates(Window *window, int x, int y) NONNULL_ARGS;
 void window_set_size(Window *window, int w, int h) NONNULL_ARGS;
-int window_get_scroll_margin(const Window *window, unsigned int scroll_margin) NONNULL_ARGS;
+unsigned int window_get_scroll_margin(const Window *window) NONNULL_ARGS;
 Window *window_prev(Window *window) NONNULL_ARGS_AND_RETURN;
 Window *window_next(Window *window) NONNULL_ARGS_AND_RETURN;
 void frame_for_each_window(const Frame *frame, void (*func)(Window*, void*), void *data) NONNULL_ARG(1, 2);

test/syntax.c

@@ -101,7 +101,7 @@ static void test_hl_line(TestContext *ctx)
     BlockIter tmp = block_iter(buffer);
     hl_fill_start_states(syn, lss, styles, &tmp, buffer->nl);
     block_iter_goto_line(&view->cursor, line_nr - 1);
-    view_update(view, 0);
+    view_update(view);
     ASSERT_EQ(view->cx, 0);
     ASSERT_EQ(view->cy, line_nr - 1);