perf annotate-data: Support folding in TUI browser

Like in the hists browser, it should support folding current entry so
that it can hide unwanted details in some data structures.

The folded entries will be displayed with the '+' sign, while unfolded
entries will have the '-' sign.

Entries that have no children will not show any signs.

  Annotate type: 'struct socket' (1 samples)
        Percent     Offset       Size  Field
  -      100.00          0        128  struct socket {                                  ◆
           0.00          0          4      socket_state   state;                        ▒
           0.00          4          2      short int      type;                         ▒
           0.00          8          8      long unsigned int      flags;                ▒
           0.00         16          8      struct file*   file;                         ▒
         100.00         24          8      struct sock*   sk;                           ▒
           0.00         32          8      struct proto_ops*      ops;                  ▒
  -        0.00         64         64      struct socket_wq       wq {                  ▒
  -        0.00         64         24          wait_queue_head_t  wait {                ▒
  +        0.00         64          4              spinlock_t     lock;                 ▒
  -        0.00         72         16              struct list_head       head {        ▒
           0.00         72          8                  struct list_head*  next;         ▒
           0.00         80          8                  struct list_head*  prev;         ▒
                                                   };                                   ▒
                                               };                                       ▒
           0.00         88          8          struct fasync_struct*      fasync_list;  ▒
           0.00         96          8          long unsigned int  flags;                ▒
  +        0.00        104         16          struct callback_head       rcu;          ▒
                                           };                                           ▒
                                       };                                               ▒

This just adds the display logic for folding, actually folding action
will be implemented in the next patch.
Signed-off-by: Namhyung Kim <namhyung@kernel.org>
Tested-by: Arnaldo Carvalho de Melo <acme@redhat.com>
Cc: Adrian Hunter <adrian.hunter@intel.com>
Cc: Ian Rogers <irogers@google.com>
Cc: Ingo Molnar <mingo@kernel.org>
Cc: Jiri Olsa <jolsa@kernel.org>
Cc: Kan Liang <kan.liang@linux.intel.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Link: https://lore.kernel.org/r/20240812194447.2049187-2-namhyung@kernel.orgSigned-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>

tools/perf/ui/browsers/annotate-data.c

@@ -14,6 +14,10 @@
 #include "util/evlist.h"
 #include "util/sort.h"
 
+#define FOLDED_SIGN  '+'
+#define UNFOLD_SIGN  '-'
+#define NOCHLD_SIGN  ' '
+
 struct annotated_data_browser {
 	struct ui_browser b;
 	struct list_head entries;
@@ -24,7 +28,11 @@ struct browser_entry {
 	struct list_head node;
 	struct annotated_member *data;
 	struct type_hist_entry *hists;
-	int indent;
+	struct browser_entry *parent;
+	struct list_head children;
+	int indent;  /*indentation level, starts from 0 */
+	int nr_entries; /* # of visible entries: self + descendents */
+	bool folded;  /* only can be false when it has children */
 };
 
 static struct annotated_data_browser *get_browser(struct ui_browser *uib)
@@ -65,13 +73,14 @@ static int get_member_overhead(struct annotated_data_type *adt,
 }
 
 static int add_child_entries(struct annotated_data_browser *browser,
+			     struct browser_entry *parent,
 			     struct annotated_data_type *adt,
 			     struct annotated_member *member,
 			     struct evsel *evsel, int indent)
 {
 	struct annotated_member *pos;
 	struct browser_entry *entry;
-	int nr_entries = 0;
+	struct list_head *parent_list;
 
 	entry = zalloc(sizeof(*entry));
 	if (entry == NULL)
@@ -84,36 +93,60 @@ static int add_child_entries(struct annotated_data_browser *browser,
 	}
 
 	entry->data = member;
+	entry->parent = parent;
 	entry->indent = indent;
 	if (get_member_overhead(adt, entry, evsel) < 0) {
 		free(entry);
 		return -1;
 	}
 
-	list_add_tail(&entry->node, &browser->entries);
-	nr_entries++;
+	INIT_LIST_HEAD(&entry->children);
+	if (parent)
+		parent_list = &parent->children;
+	else
+		parent_list = &browser->entries;
 
-	list_for_each_entry(pos, &member->children, node) {
-		int nr = add_child_entries(browser, adt, pos, evsel, indent + 1);
+	list_add_tail(&entry->node, parent_list);
 
+	list_for_each_entry(pos, &member->children, node) {
+		int nr = add_child_entries(browser, entry, adt, pos, evsel,
+					   indent + 1);
 		if (nr < 0)
 			return nr;
-
-		nr_entries += nr;
 	}
 
 	/* add an entry for the closing bracket ("}") */
 	if (!list_empty(&member->children)) {
-		entry = zalloc(sizeof(*entry));
-		if (entry == NULL)
+		struct browser_entry *bracket;
+
+		bracket = zalloc(sizeof(*bracket));
+		if (bracket == NULL)
 			return -1;
 
-		entry->indent = indent;
-		list_add_tail(&entry->node, &browser->entries);
-		nr_entries++;
+		bracket->indent = indent;
+		bracket->parent = entry;
+		bracket->folded = true;
+		bracket->nr_entries = 1;
+
+		INIT_LIST_HEAD(&bracket->children);
+		list_add_tail(&bracket->node, &entry->children);
 	}
 
-	return nr_entries;
+	/* fold child entries by default */
+	entry->folded = true;
+	entry->nr_entries = 1;
+	return 0;
+}
+
+static u32 count_visible_entries(struct annotated_data_browser *browser)
+{
+	int nr = 0;
+	struct browser_entry *entry;
+
+	list_for_each_entry(entry, &browser->entries, node)
+		nr += entry->nr_entries;
+
+	return nr;
 }
 
 static int annotated_data_browser__collect_entries(struct annotated_data_browser *browser)
@@ -123,9 +156,12 @@ static int annotated_data_browser__collect_entries(struct annotated_data_browser
 	struct evsel *evsel = hists_to_evsel(he->hists);
 
 	INIT_LIST_HEAD(&browser->entries);
+
+	add_child_entries(browser, /*parent=*/NULL, adt, &adt->self, evsel,
+			  /*indent=*/0);
+
 	browser->b.entries = &browser->entries;
-	browser->b.nr_entries = add_child_entries(browser, adt, &adt->self,
-						  evsel, /*indent=*/0);
+	browser->b.nr_entries = count_visible_entries(browser);
 	return 0;
 }
 
@@ -140,9 +176,155 @@ static void annotated_data_browser__delete_entries(struct annotated_data_browser
 	}
 }
 
+static struct browser_entry *get_first_child(struct browser_entry *entry)
+{
+	if (list_empty(&entry->children))
+		return NULL;
+
+	return list_first_entry(&entry->children, struct browser_entry, node);
+}
+
+static struct browser_entry *get_last_child(struct browser_entry *entry)
+{
+	if (list_empty(&entry->children))
+		return NULL;
+
+	return list_last_entry(&entry->children, struct browser_entry, node);
+}
+
+static bool is_first_child(struct browser_entry *entry)
+{
+	/* This will be checked in a different way */
+	if (entry->parent == NULL)
+		return false;
+
+	return get_first_child(entry->parent) == entry;
+}
+
+static bool is_last_child(struct browser_entry *entry)
+{
+	/* This will be checked in a different way */
+	if (entry->parent == NULL)
+		return false;
+
+	return get_last_child(entry->parent) == entry;
+}
+
+static struct browser_entry *browser__prev_entry(struct ui_browser *uib,
+						 struct browser_entry *entry)
+{
+	struct annotated_data_browser *browser = get_browser(uib);
+	struct browser_entry *first;
+
+	first = list_first_entry(&browser->entries, struct browser_entry, node);
+
+	while (entry != first) {
+		if (is_first_child(entry))
+			entry = entry->parent;
+		else {
+			entry = list_prev_entry(entry, node);
+			while (!entry->folded)
+				entry = get_last_child(entry);
+		}
+
+		if (!uib->filter || !uib->filter(uib, &entry->node))
+			return entry;
+	}
+	return first;
+}
+
+static struct browser_entry *browser__next_entry(struct ui_browser *uib,
+						 struct browser_entry *entry)
+{
+	struct annotated_data_browser *browser = get_browser(uib);
+	struct browser_entry *last;
+
+	last = list_last_entry(&browser->entries, struct browser_entry, node);
+	while (!last->folded)
+		last = get_last_child(last);
+
+	while (entry != last) {
+		if (!entry->folded)
+			entry = get_first_child(entry);
+		else {
+			while (is_last_child(entry))
+				entry = entry->parent;
+
+			entry = list_next_entry(entry, node);
+		}
+
+		if (!uib->filter || !uib->filter(uib, &entry->node))
+			return entry;
+	}
+	return last;
+}
+
+static void browser__seek(struct ui_browser *uib, off_t offset, int whence)
+{
+	struct annotated_data_browser *browser = get_browser(uib);
+	struct browser_entry *entry;
+
+	if (uib->nr_entries == 0)
+		return;
+
+	switch (whence) {
+	case SEEK_SET:
+		entry = list_first_entry(&browser->entries, typeof(*entry), node);
+		if (uib->filter && uib->filter(uib, &entry->node))
+			entry = browser__next_entry(uib, entry);
+		break;
+	case SEEK_CUR:
+		entry = list_entry(uib->top, typeof(*entry), node);
+		break;
+	case SEEK_END:
+		entry = list_last_entry(&browser->entries, typeof(*entry), node);
+		while (!entry->folded)
+			entry = get_last_child(entry);
+		if (uib->filter && uib->filter(uib, &entry->node))
+			entry = browser__prev_entry(uib, entry);
+		break;
+	default:
+		return;
+	}
+
+	assert(entry != NULL);
+
+	if (offset > 0) {
+		while (offset-- != 0)
+			entry = browser__next_entry(uib, entry);
+	} else {
+		while (offset++ != 0)
+			entry = browser__prev_entry(uib, entry);
+	}
+
+	uib->top = &entry->node;
+}
+
 static unsigned int browser__refresh(struct ui_browser *uib)
 {
-	return ui_browser__list_head_refresh(uib);
+	struct browser_entry *entry, *next;
+	int row = 0;
+
+	if (uib->top == NULL || uib->top == uib->entries)
+		browser__seek(uib, SEEK_SET, 0);
+
+	entry = list_entry(uib->top, typeof(*entry), node);
+
+	while (true) {
+		if (!uib->filter || !uib->filter(uib, &entry->node)) {
+			ui_browser__gotorc(uib, row, 0);
+			uib->write(uib, entry, row);
+			if (++row == uib->rows)
+				break;
+		}
+		next = browser__next_entry(uib, entry);
+		if (next == entry)
+			break;
+
+		entry = next;
+	}
+
+	return row;
 }
 
 static int browser__show(struct ui_browser *uib)
@@ -171,7 +353,7 @@ static int browser__show(struct ui_browser *uib)
 		strcpy(title, "Percent");
 
 	ui_browser__printf(uib, "%*s %10s %10s %10s  %s",
-			   11 * (browser->nr_events - 1), "",
+			   2 + 11 * (browser->nr_events - 1), "",
 			   title, "Offset", "Size", "Field");
 	ui_browser__write_nstring(uib, "", uib->width);
 	return 0;
@@ -208,12 +390,12 @@ static void browser__write(struct ui_browser *uib, void *entry, int row)
 	struct evsel *leader = hists_to_evsel(he->hists);
 	struct evsel *evsel;
 	int idx = 0;
+	bool current = ui_browser__is_current_entry(uib, row);
 
 	if (member == NULL) {
-		bool current = ui_browser__is_current_entry(uib, row);
-
 		/* print the closing bracket */
 		ui_browser__set_percent_color(uib, 0, current);
+		ui_browser__printf(uib, "%c ", NOCHLD_SIGN);
 		ui_browser__write_nstring(uib, "", 11 * browser->nr_events);
 		ui_browser__printf(uib, " %10s %10s  %*s};",
 				   "", "", be->indent * 4, "");
@@ -221,6 +403,13 @@ static void browser__write(struct ui_browser *uib, void *entry, int row)
 		return;
 	}
 
+	ui_browser__set_percent_color(uib, 0, current);
+
+	if (!list_empty(&be->children))
+		ui_browser__printf(uib, "%c ", be->folded ? FOLDED_SIGN : UNFOLD_SIGN);
+	else
+		ui_browser__printf(uib, "%c ", NOCHLD_SIGN);
+
 	/* print the number */
 	for_each_group_evsel(evsel, leader) {
 		struct type_hist *h = adt->histograms[evsel->core.idx];
@@ -237,13 +426,13 @@ static void browser__write(struct ui_browser *uib, void *entry, int row)
 		ui_browser__printf(uib, " %10d %10d  %s%s",
 				   member->offset, member->size,
 				   member->type_name,
-				   list_empty(&member->children) ? ";" : " {");
+				   list_empty(&member->children) || be->folded? ";" : " {");
 	} else {
 		ui_browser__printf(uib, " %10d %10d  %*s%s\t%s%s",
 				   member->offset, member->size,
 				   be->indent * 4, "", member->type_name,
 				   member->var_name ?: "",
-				   list_empty(&member->children) ? ";" : " {");
+				   list_empty(&member->children) || be->folded ? ";" : " {");
 	}
 	/* fill the rest */
 	ui_browser__write_nstring(uib, "", uib->width);
@@ -297,7 +486,7 @@ int hist_entry__annotate_data_tui(struct hist_entry *he, struct evsel *evsel,
 	struct annotated_data_browser browser = {
 		.b = {
 			.refresh = browser__refresh,
-			.seek	 = ui_browser__list_head_seek,
+			.seek	 = browser__seek,
 			.write	 = browser__write,
 			.priv	 = he,
 			.extra_title_lines = 1,