ui: cap and cheapen the dock's events rebuild

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

src/ui_app.hpp

@@ -1797,7 +1797,12 @@ void dock_measure_value(App& app, std::size_t i, const std::string& text);
 /// of what is *on screen* (in place, no rebuild), `dock_events_set_sensitive()` is the one writer of the
 /// block's sensitivity. All three are no-ops before the block is built.
 GtkWidget* build_events_dock(App& app);
+/// The dock shows at most this many events (the newest), then one dim "... N more, see Manage" row.
+inline constexpr std::size_t kDockEventsMax = 24;
+/// The first lists the store itself; the second takes a list the caller already holds (so one refresh
+/// reads the cache directory once, not twice). Both keep the list's vertical scroll across the rebuild.
 void dock_rebuild_events(App& app);
+void dock_rebuild_events(App& app, const std::vector<EventRecord>& records);
 void dock_mark_events(App& app);
 void dock_events_set_sensitive(App& app, bool available);
 /// A row's first line, and the two questions its mark is made of (`ui_events.cpp`): the one function

src/ui_dock.cpp

@@ -18,6 +18,7 @@
 
 #include <gtk/gtk.h>
 
+#include <algorithm>
 #include <cstring>
 #include <ctime>
 #include <string>
@@ -238,7 +239,7 @@ namespace {
 /// The widths of an event row's three cells, in characters. Fixed, so the Events block is as wide with
 /// one event as with thirty (the marker is one cell wide even when it is empty).
 constexpr int kEventTitleChars = 18;
-constexpr int kEventTimeChars = 8;
+constexpr int kEventSeqChars = 8;
 
 /// The one-character mark of a row: filled for the event on screen, hollow for a member of the group on
 /// screen, blank for the rest. Both questions are the ones `event_row_title()` asks (`ui_events.cpp`).
@@ -255,6 +256,11 @@ void on_manage_events(GtkButton*, gpointer user) {
 /// One click on a row replays it, as the pane's activation does: `replay_event()` and then the in-place
 /// re-mark. The record is copied first, because nothing it triggers may be allowed to free the row it
 /// was read from.
+///
+/// Safety depends on `replay_event()` never rebuilding the dock's list (it must go through
+/// `dock_mark_events()`, which rewrites labels in place): a rebuild here would free this very row, and
+/// `row`, `record` and the list box's own emission of `row-activated` would all be dangling. The copy
+/// guards the record only, not the row. If a replay ever has to refresh the cache's view, defer it.
 void on_dock_event_activated(GtkListBox*, GtkListBoxRow* row, gpointer user) {
   App& app = *static_cast<App*>(user);
   if (row == nullptr) return;
@@ -266,15 +272,6 @@ void on_dock_event_activated(GtkListBox*, GtkListBoxRow* row, gpointer user) {
   mark_events_on_screen(app);
 }
 
-std::string event_clock(const EventRecord& r) {
-  const std::time_t t = static_cast<std::time_t>(r.wall_time);
-  std::tm tm{};
-  localtime_r(&t, &tm);
-  char clock[32];
-  std::strftime(clock, sizeof(clock), "%H:%M:%S", &tm);
-  return clock;
-}
-
 }  // namespace
 
 GtkWidget* build_events_dock(App& app) {
@@ -323,9 +320,47 @@ GtkWidget* build_events_dock(App& app) {
 
 void dock_rebuild_events(App& app) {
   if (app.dock_events_list == nullptr || app.event_store == nullptr) return;
+  dock_rebuild_events(app, app.event_store->list());
+}
+
+namespace {
+
+/// Puts the list's vertical scroll back after a refill. The adjustment's bounds are only updated at the
+/// next allocation, so the value set at once is clamped against the old ones; an idle (which runs after the
+/// frame that laid the new rows out) sets it again against the new bounds, where the clamp is exact.
+void restore_dock_scroll(GtkWidget* list, double value) {
+  GtkWidget* scroller = gtk_widget_get_ancestor(list, GTK_TYPE_SCROLLED_WINDOW);
+  if (scroller == nullptr) return;
+  GtkAdjustment* adj = gtk_scrolled_window_get_vadjustment(GTK_SCROLLED_WINDOW(scroller));
+  gtk_adjustment_set_value(adj, value);
+  struct Pending {
+    GtkAdjustment* adj;
+    double value;
+  };
+  auto* p = new Pending{GTK_ADJUSTMENT(g_object_ref(adj)), value};
+  g_idle_add_full(
+      G_PRIORITY_DEFAULT_IDLE,
+      [](gpointer d) -> gboolean {
+        auto* q = static_cast<Pending*>(d);
+        gtk_adjustment_set_value(q->adj, q->value);
+        g_object_unref(q->adj);
+        delete q;
+        return G_SOURCE_REMOVE;
+      },
+      p, nullptr);
+}
+
+}  // namespace
+
+void dock_rebuild_events(App& app, const std::vector<EventRecord>& records) {
+  if (app.dock_events_list == nullptr) return;
   GtkListBox* list = GTK_LIST_BOX(app.dock_events_list);
+  GtkWidget* scroller = gtk_widget_get_ancestor(app.dock_events_list, GTK_TYPE_SCROLLED_WINDOW);
+  const double scroll =
+      scroller != nullptr
+          ? gtk_adjustment_get_value(gtk_scrolled_window_get_vadjustment(GTK_SCROLLED_WINDOW(scroller)))
+          : 0.0;
   gtk_list_box_remove_all(list);
-  const std::vector<EventRecord> records = app.event_store->list();
   if (records.empty()) {
     GtkWidget* none = gtk_label_new("no events yet");
     gtk_widget_set_halign(none, GTK_ALIGN_START);
@@ -340,7 +375,11 @@ void dock_rebuild_events(App& app) {
     gtk_list_box_append(list, row);
     return;
   }
-  for (const EventRecord& r : records) {
+  // The newest `kDockEventsMax` only: the list is newest first, and a block that builds four widgets per
+  // cached event is a cost that grows with a cache the user may have set to unbounded.
+  const std::size_t shown = std::min(records.size(), kDockEventsMax);
+  for (std::size_t i = 0; i < shown; ++i) {
+    const EventRecord& r = records[i];
     GtkWidget* row = gtk_list_box_row_new();
     GtkWidget* line = gtk_box_new(GTK_ORIENTATION_HORIZONTAL, 6);
     gtk_widget_set_margin_start(line, 6);
@@ -355,10 +394,13 @@ void dock_rebuild_events(App& app) {
     gtk_widget_set_hexpand(name, true);
     gtk_widget_set_tooltip_text(name, text.c_str());
     gtk_box_append(GTK_BOX(line), name);
-    const std::string clock = event_clock(r);
+    // The latch's sequence number, as the pane's third line ends with it: the title already carries the
-    GtkWidget* when = fixed_label(clock.c_str(), kEventTimeChars, GTK_ALIGN_END);
+    // clock, so this is the part of the row that is not in it.
-    gtk_widget_add_css_class(when, "dim-label");
+    const std::string seq = "#" + std::to_string(r.seq);
-    gtk_box_append(GTK_BOX(line), when);
+    GtkWidget* num = fixed_label(seq.c_str(), kEventSeqChars, GTK_ALIGN_END);
+    gtk_widget_set_tooltip_text(num, ("latch " + seq).c_str());
+    gtk_widget_add_css_class(num, "dim-label");
+    gtk_box_append(GTK_BOX(line), num);
 
     g_object_set_data(G_OBJECT(row), "udpscope-event-marker", marker);
     g_object_set_data(G_OBJECT(row), "udpscope-event-title", name);
@@ -367,6 +409,22 @@ void dock_rebuild_events(App& app) {
     gtk_list_box_row_set_child(GTK_LIST_BOX_ROW(row), line);
     gtk_list_box_append(list, row);
   }
+  if (records.size() > shown) {
+    // A last row with no record (like the placeholder: `dock_mark_events()` skips it, and it does nothing
+    // when activated). Fixed text and the same ellipsis as the rest, so it cannot widen the dock.
+    const std::string more = "\xE2\x80\xA6 " + std::to_string(records.size() - shown) + " more, see Manage";
+    GtkWidget* label = fixed_label(more.c_str(), kEventTitleChars + kEventSeqChars, GTK_ALIGN_START);
+    gtk_widget_add_css_class(label, "dim-label");
+    gtk_widget_set_tooltip_text(label, more.c_str());
+    gtk_widget_set_margin_start(label, 6);
+    gtk_widget_set_margin_top(label, 4);
+    gtk_widget_set_margin_bottom(label, 4);
+    GtkWidget* row = gtk_list_box_row_new();
+    gtk_list_box_row_set_child(GTK_LIST_BOX_ROW(row), label);
+    gtk_list_box_row_set_activatable(GTK_LIST_BOX_ROW(row), false);
+    gtk_list_box_append(list, row);
+  }
+  restore_dock_scroll(app.dock_events_list, scroll);
 }
 
 void dock_mark_events(App& app) {

src/ui_events.cpp

@@ -782,10 +782,8 @@ void attach_preview_zoom(GtkWidget* frame, const std::string& path) {
                         GConnectFlags(0));
 }
 
-/// A row's first line: when the event was latched, how long it is, and whether it is the one on
+/// Whether the event is the one on screen: the one question the title's "(on screen)" and the dock's
-/// screen. One function because two callers write it -- the row builder and the in-place
+/// filled mark both ask.
-/// re-mark -- and a mark that reads differently depending on which of them last ran would be
-/// worse than no mark.
 bool event_on_screen(const App& app, const EventRecord& r) {
   return std::string(app.waveform_name) == r.file;
 }
@@ -797,6 +795,10 @@ bool event_in_group(const App& app, const EventRecord& r) {
                      [&](const EventRecord& g) { return g.file == r.file; });
 }
 
+/// A row's first line: when the event was latched, how long it is, and whether it is the one on
+/// screen. One function because two callers write it -- the row builder and the in-place
+/// re-mark -- and a mark that reads differently depending on which of them last ran would be
+/// worse than no mark.
 std::string event_row_title(App& app, const EventRecord& r) {
   const std::time_t t = static_cast<std::time_t>(r.wall_time);
   std::tm tm{};
@@ -828,7 +830,7 @@ void mark_events_on_screen(App& app) {
 /// the whole pane describes whichever event happens to be newest rather than the one being read. The
 /// numbers are one line each: a list that has to load the samples to describe an event is a list that
 /// cannot show thirty of them.
-static void rebuild_events_pane_list(App& app) {
+static void rebuild_events_pane_list(App& app, std::vector<EventRecord>& records) {
   if (app.events_list == nullptr) return;
   while (GtkWidget* child = gtk_widget_get_first_child(app.events_list)) {
     gtk_list_box_remove(GTK_LIST_BOX(app.events_list), child);
@@ -838,8 +840,8 @@ static void rebuild_events_pane_list(App& app) {
   // the one that finds out.
   app.events_thumb = nullptr;
   if (app.event_store == nullptr) return;
-  // Not const: a record whose preview had to be redrawn learns its thumbnail's path here.
+  // `records` is the caller's list, not const: a record whose preview had to be redrawn learns its
-  std::vector<EventRecord> records = app.event_store->list();
+  // thumbnail's path here.
   if (records.empty()) {
     GtkWidget* empty = gtk_label_new("no events yet -- arm the trigger");
     gtk_widget_add_css_class(empty, "dim-label");
@@ -975,8 +977,12 @@ static void rebuild_events_pane_list(App& app) {
 /// Both views of the cache, rebuilt from the same list: the pane's rows (with their pictures) and the
 /// dock's compact ones. The dock follows even when the pane's list does not exist.
 void refresh_events_pane(App& app) {
-  rebuild_events_pane_list(app);
+  // One read of the cache directory for both views (none without a store, which the pane's rebuild
-  dock_rebuild_events(app);
+  // and the dock's both treat as nothing to list).
+  std::vector<EventRecord> records;
+  if (app.event_store != nullptr) records = app.event_store->list();
+  rebuild_events_pane_list(app, records);
+  if (app.event_store != nullptr) dock_rebuild_events(app, records);
 }
 
 /// Clicking a row replays it: the same loader `--open` uses, on the event's file. The acquisition is

src/ui_probe.cpp

@@ -5579,14 +5579,19 @@ void report_live_restored(App& a, const char* what) {
 /// The dock's Events block against the pane's list. `same_titles` compares each dock row's title label
 /// with the pane row's, in order (both are rebuilt from the same list by `refresh_events_pane()`, and both
 /// are marked by `mark_events_on_screen()`); `on_screen` counts the dock rows with the filled marker, and
-/// `marked` is the index of the first one (-1 for none).
+/// `marked` is the index of the first one (-1 for none). `max_ok` is the cap: no more than
-static void report_dock_events(App& a, const char* what) {
+/// `kDockEventsMax` event rows and one "more" row. `expected_marked` is read after a replay of a record
+/// the caller names by file (`expected_file`): 1 when exactly one dock row is filled and its record is that
+/// one (record identity, not a count), 0 otherwise, -1 when the caller names none.
+static void report_dock_events(App& a, const char* what, const std::string& expected_file = std::string()) {
   std::vector<std::string> dock_titles;
+  std::string filled_file;
+  int dock_children = 0;
   std::vector<std::string> pane_titles;
   int on_screen = 0;
   int marked = -1;
   int members = 0;
-  const auto titles = [&members](GtkWidget* list, std::vector<std::string>* out, int* filled, int* first) {
+  const auto titles = [&members, &filled_file](GtkWidget* list, std::vector<std::string>* out, int* filled, int* first) {
     if (list == nullptr) return;
     int i = 0;
     for (GtkWidget* row = gtk_widget_get_first_child(list); row != nullptr;
@@ -5603,22 +5608,41 @@ static void report_dock_events(App& a, const char* what) {
       if (filled != nullptr && marker != nullptr &&
           std::strcmp(gtk_label_get_text(GTK_LABEL(marker)), "\xE2\x97\x8F") == 0) {
         ++*filled;
-        if (first != nullptr && *first < 0) *first = i;
+        if (first != nullptr && *first < 0) {
+          *first = i;
+          filled_file = static_cast<const EventRecord*>(g_object_get_data(G_OBJECT(row), "udpscope-event"))->file;
+        }
       }
     }
   };
+  for (GtkWidget* row = a.dock_events_list != nullptr ? gtk_widget_get_first_child(a.dock_events_list) : nullptr;
+       row != nullptr; row = gtk_widget_get_next_sibling(row)) {
+    ++dock_children;
+  }
   titles(a.dock_events_list, &dock_titles, &on_screen, &marked);
   titles(a.events_list, &pane_titles, nullptr, nullptr);
+  // The dock shows the newest `kDockEventsMax` only: its titles are the pane's first ones, in order.
+  if (pane_titles.size() > kDockEventsMax) pane_titles.resize(kDockEventsMax);
   std::fprintf(stderr,
                "[events] dock events: rows=%zu pane_rows=%zu same_titles=%d sensitive=%d dock_w=%d "
-               "on_screen=%d marked=%d members=%d at=%s\n",
+               "on_screen=%d marked=%d members=%d max_ok=%d expected_marked=%d at=%s\n",
                dock_titles.size(), pane_titles.size(), dock_titles == pane_titles ? 1 : 0,
                a.dock_events_box != nullptr && gtk_widget_is_sensitive(a.dock_events_box) ? 1 : 0,
                a.dock_events_box != nullptr ? gtk_widget_get_width(a.dock_events_box) : -1, on_screen,
-               marked, members, what);
+               marked, members, dock_children <= static_cast<int>(kDockEventsMax) + 1 ? 1 : 0,
+               expected_file.empty() ? -1 : (on_screen == 1 && filled_file == expected_file ? 1 : 0), what);
   std::fflush(stderr);
 }
 
+/// The file of the record the Nth row of a list carries ("" for a row without one).
+static std::string listed_file(GtkWidget* list, int index) {
+  if (list == nullptr) return std::string();
+  GtkListBoxRow* row = gtk_list_box_get_row_at_index(GTK_LIST_BOX(list), index);
+  if (row == nullptr) return std::string();
+  const auto* r = static_cast<const EventRecord*>(g_object_get_data(G_OBJECT(row), "udpscope-event"));
+  return r != nullptr ? r->file : std::string();
+}
+
 void events_probe_next(App& a, int step, guint delay_ms) {
   a.dbg_events_step = step;
   g_timeout_add(delay_ms, events_probe_step, &a);
@@ -5805,7 +5829,9 @@ gboolean events_probe_step(gpointer user) {
                  a->events_thumb != nullptr && gtk_widget_get_mapped(a->events_thumb) ? 1 : 0,
                  rows_kept ? 1 : 0, selected_now, a->dbg_events_selected);
     std::fflush(stderr);
-    report_dock_events(*a, "after pane replay");
+    // The pane replayed its own row 0; the dock's list is the same list, so the dock's filled marker has to
+    // be on the row whose record is that one.
+    report_dock_events(*a, "after pane replay", listed_file(a->events_list, 0));
     // One click on a dock row, the gesture: a *second* event when there is one, so the marker has to
     // move. Through `row-activated`, which is what a single click emits.
     {
@@ -5813,6 +5839,9 @@ gboolean events_probe_step(gpointer user) {
       GtkListBoxRow* row = gtk_list_box_get_row_at_index(dock, 1);
       if (row == nullptr) row = gtk_list_box_get_row_at_index(dock, 0);
       const bool real = row != nullptr && g_object_get_data(G_OBJECT(row), "udpscope-event") != nullptr;
+      const std::string clicked_file =
+          real ? static_cast<const EventRecord*>(g_object_get_data(G_OBJECT(row), "udpscope-event"))->file
+               : std::string();
       const std::string before = a->waveform_name;
       if (real) g_signal_emit_by_name(dock, "row-activated", row);
       // Already replaying (the pane's click above), so `replaying` alone cannot tell the click from the
@@ -5821,7 +5850,7 @@ gboolean events_probe_step(gpointer user) {
       std::fprintf(stderr, "[events] dock replay: clicked=%d replaying=%d waveform_changed=%d\n",
                    real ? 1 : 0, a->replaying ? 1 : 0, before != a->waveform_name ? 1 : 0);
       std::fflush(stderr);
-      report_dock_events(*a, "after dock click");
+      report_dock_events(*a, "after dock click", clicked_file);
     }
     events_probe_next(*a, 2, 1200);
     return G_SOURCE_REMOVE;
@@ -6054,10 +6083,11 @@ gboolean events_group_probe_step(gpointer user) {
       GtkListBox* dock = GTK_LIST_BOX(a->dock_events_list);
       GtkListBoxRow* row = gtk_list_box_get_row_at_index(dock, 1);
       const bool real = row != nullptr && g_object_get_data(G_OBJECT(row), "udpscope-event") != nullptr;
+      const std::string clicked_file = real ? listed_file(a->dock_events_list, 1) : std::string();
       if (real) g_signal_emit_by_name(dock, "row-activated", row);
       std::fprintf(stderr, "[events] dock replay: clicked=%d replaying=%d (second click, live before)\n",
                    real ? 1 : 0, a->replaying ? 1 : 0);
-      report_dock_events(*a, "second dock click");
+      report_dock_events(*a, "second dock click", clicked_file);
     }
     return G_SOURCE_REMOVE;
   }