[View] Apply a requested selection after the reload that carries it

rofi_view_set_selected_line() resolves the line against line_map, which only
describes content the view has already loaded. A mode that reloads and selects
in one go cannot satisfy that: rofi_view_reload() arms the backend's reload
timer, and line_map is rebuilt later, in rofi_view_refilter_real(). The lookup
therefore ran against the previous list and fell back to row 0 whenever the
requested line was out of its range, leaving rofi_view_get_selected_line() and
listview_get_selected() disagreeing.

Record such a request in state->pending_selected_line instead of falling back to
row 0, and apply it in refilter, in the same pass that installs the new content
and before it repaints, so no frame shows the wrong row. Requests are one-shot
and honoured only on the reload path: state->selected_line is stale between
activations, so re-applying it on an ordinary refilter would move the selection
away from where the user left it.

Script mode's keep-selection is affected: it bounds-checks new-selection against
the new list length, then resolves it against the old line_map.

Author: vredesbyyrd

include/view-internal.h

@@ -101,6 +101,9 @@ struct RofiViewState {
   int skip_absorb;
   /** The selected line (in the unfiltered list) */
   unsigned int selected_line;
+  /** Selection requested before the content it refers to was loaded, applied
+   * on the next reload. UINT32_MAX when there is none. */
+  unsigned int pending_selected_line;
   /** The previously selected line (in the unfiltered list) */
   unsigned int previous_line;
   /** The return state of the view */

source/view.c

@@ -344,20 +344,38 @@ void rofi_view_set_active(RofiViewState *state) {
   rofi_view_queue_redraw();
 }
 
+/**
+ * @param state The current RofiViewState
+ * @param line The line (in the unfiltered list) to move the selection to
+ *
+ * Move the selection to `line`, if it is part of the loaded content.
+ *
+ * @returns TRUE when the line was found.
+ */
+static gboolean rofi_view_select_line(RofiViewState *state, unsigned int line) {
+  if (line == UINT32_MAX) {
+    return FALSE;
+  }
+  for (unsigned int i = 0; i < state->filtered_lines; i++) {
+    if (state->line_map[i] == line) {
+      listview_set_selected(state->list_view, i);
+      return TRUE;
+    }
+  }
+  return FALSE;
+}
+
 void rofi_view_set_selected_line(RofiViewState *state,
                                  unsigned int selected_line) {
   state->selected_line = selected_line;
-  // Find the line.
-  unsigned int selected = 0;
-  for (unsigned int i = 0; ((state->selected_line)) < UINT32_MAX && !selected &&
-                           i < state->filtered_lines;
-       i++) {
-    if (state->line_map[i] == (state->selected_line)) {
-      selected = i;
-      break;
-    }
+  /* line_map only describes content the view has already loaded; a reload
+   * rebuilds it later, in rofi_view_refilter_real(). Record what cannot be
+   * resolved yet instead of falling back to row 0, which would show the wrong
+   * selection until that reload lands. */
+  state->pending_selected_line = selected_line;
+  if (rofi_view_select_line(state, selected_line)) {
+    state->pending_selected_line = UINT32_MAX;
   }
-  listview_set_selected(state->list_view, selected);
 #ifdef ENABLE_XCB
   if (config.backend == DISPLAY_XCB) {
     // Clear the window and force an expose event resulting in a redraw.
@@ -419,7 +437,10 @@ const char *rofi_view_get_user_input(const RofiViewState *state) {
  * @returns a new 0 initialized RofiViewState
  */
 static RofiViewState *__rofi_view_state_create(void) {
-  return g_malloc0(sizeof(RofiViewState));
+  RofiViewState *state = g_malloc0(sizeof(RofiViewState));
+  // 0 is a valid line, so the sentinel has to be set explicitly.
+  state->pending_selected_line = UINT32_MAX;
+  return state;
 }
 
 /**
@@ -784,9 +805,11 @@ static gboolean rofi_view_refilter_real(RofiViewState *state) {
   }
   GTimer *timer = g_timer_new();
   TICK_N("Filter start");
+  gboolean content_reloaded = FALSE;
   if (state->reload) {
     _rofi_view_reload_row(state);
     state->reload = FALSE;
+    content_reloaded = TRUE;
   }
   TICK_N("Filter reload rows");
   if (state->tokens) {
@@ -882,6 +905,18 @@ static gboolean rofi_view_refilter_real(RofiViewState *state) {
   TICK_N("Filter matching done");
   listview_set_num_elements(state->list_view, state->filtered_lines);
 
+  /* line_map now describes the content this pass installed, so a selection
+   * requested before it existed can be resolved. Doing so before the
+   * rofi_view_update() below keeps the wrong row off the first frame. Only on
+   * the reload path: a plain refilter would consume the request and drop it. */
+  if (content_reloaded && state->pending_selected_line != UINT32_MAX) {
+    unsigned int pending = state->pending_selected_line;
+    state->pending_selected_line = UINT32_MAX;
+    if (rofi_view_select_line(state, pending)) {
+      state->selected_line = pending;
+    }
+  }
+
   if (state->tb_filtered_rows) {
     char *r = g_strdup_printf("%u", state->filtered_lines);
     textbox_text(state->tb_filtered_rows, r);