From a51f08e5324252a7aafb94a2c901ee8af46f6eca Mon Sep 17 00:00:00 2001
From: Charles Kerr <charles@charleskerr.com>
Date: Sat, 27 Jan 2024 09:33:12 -0600
Subject: [PATCH] perf: prefer small containers (#6542)

* perf: make pref_is_savable() constexpr

* refactor: use std::vector in tr_torrents::removedSince()

* chore: remove unused typedef in OptionsDialog

* perf: use std::vector in tr_num_parse_range()

* perf: use small::max_size_set in FileTreeItem::update()

* perf: use small:set in Wishlist::next()

* perf: use small:map in FilterBar

* perf: use small::map for counts in tr_logAddMessage()

* perf: use small::max_size_map in FileTreeModel::twiddleWanted()

perf: use small::max_size_map in FileTreeModel::twiddlePriority()

* perf: use a std::array instead of std::map in TorrentFilter::update()

* perf: use a std::array instead of std::map in TorrentSorter::set_mode()

* perf: use a std::array instead of std::map in TorrentSorter::update()

* perf: use small::set in Application::Impl::on_rpc_changed_idle()

* perf: use std::array for MessageLogColumnsModel::level_names_

* fixup! perf: use std::array for MessageLogColumnsModel::level_names_

* fixup! perf: use small::map for counts in tr_logAddMessage()
---
 gtk/.clang-format                    |  2 +-
 gtk/Application.cc                   |  7 +++++--
 gtk/MessageLogWindow.cc              | 27 +++++++++++++++----------
 gtk/TorrentFilter.cc                 | 14 +++++++++----
 gtk/TorrentSorter.cc                 | 30 ++++++++++++++++------------
 libtransmission/log.cc               | 16 +++++++--------
 libtransmission/peer-mgr-wishlist.cc |  8 +++++---
 libtransmission/torrents.cc          | 10 ++++++----
 libtransmission/utils.cc             |  8 +++++---
 qt/FileTreeItem.cc                   |  5 +++--
 qt/FileTreeModel.cc                  |  7 ++++---
 qt/FilterBar.cc                      |  2 +-
 qt/FilterBar.h                       |  5 +++--
 qt/OptionsDialog.h                   |  2 --
 qt/Prefs.cc                          | 19 +++++++++++++-----
 qt/Prefs.h                           |  1 -
 16 files changed, 97 insertions(+), 66 deletions(-)

diff --git a/gtk/.clang-format b/gtk/.clang-format
index 2799fd6a6..d5b141488 100644
--- a/gtk/.clang-format
+++ b/gtk/.clang-format
@@ -11,7 +11,7 @@ IncludeCategories:
     SortPriority: 4
   - Regex: '^<(cairo|gdk|gio|glib|gtk|pango)mm([-./]|config)'
     Priority: 5
-  - Regex: '^<(fmt)/'
+  - Regex: '^<(fmt|small)/'
     Priority: 6
   - Regex: '^<(cairo|gdk|gio|glib|gtk|pango)[-./]'
     Priority: 8
diff --git a/gtk/Application.cc b/gtk/Application.cc
index 7540ae9b0..1835c0f3f 100644
--- a/gtk/Application.cc
+++ b/gtk/Application.cc
@@ -52,6 +52,8 @@
 #include <gtkmm/stylecontext.h>
 #include <gtkmm/window.h>
 
+#include <small/set.hpp>
+
 #if GTKMM_CHECK_VERSION(4, 0, 0)
 #include <gtkmm/droptarget.h>
 #include <gtkmm/eventcontrollerfocus.h>
@@ -70,7 +72,6 @@
 #include <iterator> // std::back_inserter
 #include <map>
 #include <memory>
-#include <set>
 #include <sstream>
 #include <string>
 #include <thread>
@@ -478,11 +479,13 @@ bool Application::Impl::on_rpc_changed_idle(tr_rpc_callback_type type, tr_torren
             auto const newvals = tr_sessionGetSettings(session);
 
             // determine which settings changed
-            auto changed_keys = std::set<tr_quark>{};
+            auto changed_keys = small::set<tr_quark>{};
             auto& oldvals = gtr_pref_get_all();
             auto const serde = tr_variant_serde::benc();
             if (auto const* const newvals_map = newvals.get_if<tr_variant::Map>(); newvals_map != nullptr)
             {
+                changed_keys.reserve(std::size(*newvals_map));
+
                 for (auto const& [key, newval] : *newvals_map)
                 {
                     bool changed = true;
diff --git a/gtk/MessageLogWindow.cc b/gtk/MessageLogWindow.cc
index 5d1f4b198..1f3289465 100644
--- a/gtk/MessageLogWindow.cc
+++ b/gtk/MessageLogWindow.cc
@@ -36,9 +36,10 @@
 #include <fmt/core.h>
 #include <fmt/ostream.h>
 
+#include <array>
 #include <fstream>
-#include <map>
 #include <memory>
+#include <utility>
 
 class MessageLogColumnsModel : public Gtk::TreeModelColumnRecord
 {
@@ -95,7 +96,14 @@ private:
     tr_log_level maxLevel_ = TR_LOG_INFO;
     bool isPaused_ = false;
     sigc::connection refresh_tag_;
-    std::map<tr_log_level, char const*> const level_names_;
+
+    static auto const inline level_names_ = std::array<std::pair<tr_log_level, char const*>, 5U>{ {
+        { TR_LOG_CRITICAL, C_("Logging level", "Critical") },
+        { TR_LOG_ERROR, C_("Logging level", "Error") },
+        { TR_LOG_WARN, C_("Logging level", "Warning") },
+        { TR_LOG_INFO, C_("Logging level", "Information") },
+        { TR_LOG_DEBUG, C_("Logging level", "Debug") },
+    } };
 };
 
 namespace
@@ -163,6 +171,7 @@ void MessageLogWindow::Impl::level_combo_init(Gtk::ComboBox* level_combo) const
 
     auto has_pref_level = false;
     auto items = std::vector<std::pair<Glib::ustring, int>>{};
+    items.reserve(std::size(level_names_));
     for (auto const& [level, name] : level_names_)
     {
         items.emplace_back(name, level);
@@ -213,8 +222,11 @@ void MessageLogWindow::Impl::doSave(std::string const& filename)
             auto const* const node = row.get_value(message_log_cols.tr_msg);
             auto const date = gtr_asctime(node->when);
 
-            auto const it = level_names_.find(node->level);
-            auto const* const level_str = it != std::end(level_names_) ? it->second : "???";
+            auto const iter = std::find_if(
+                std::begin(level_names_),
+                std::end(level_names_),
+                [key = node->level](auto const& item) { return item.first == key; });
+            auto const* const level_str = iter != std::end(level_names_) ? iter->second : "???";
 
             fmt::print(stream, "{}\t{}\t{}\t{}\n", date, level_str, node->name, node->message);
         }
@@ -477,13 +489,6 @@ MessageLogWindow::Impl::Impl(
     , refresh_tag_(Glib::signal_timeout().connect_seconds(
           sigc::mem_fun(*this, &Impl::onRefresh),
           SECONDARY_WINDOW_REFRESH_INTERVAL_SECONDS))
-    , level_names_{ {
-          { TR_LOG_CRITICAL, C_("Logging level", "Critical") },
-          { TR_LOG_ERROR, C_("Logging level", "Error") },
-          { TR_LOG_WARN, C_("Logging level", "Warning") },
-          { TR_LOG_INFO, C_("Logging level", "Information") },
-          { TR_LOG_DEBUG, C_("Logging level", "Debug") },
-      } }
 {
     /**
     ***  toolbar
diff --git a/gtk/TorrentFilter.cc b/gtk/TorrentFilter.cc
index e53d9eeae..8e9c519f7 100644
--- a/gtk/TorrentFilter.cc
+++ b/gtk/TorrentFilter.cc
@@ -10,6 +10,9 @@
 
 #include <libtransmission/transmission.h>
 
+#include <array>
+#include <utility>
+
 TorrentFilter::TorrentFilter()
     : Glib::ObjectBase(typeid(TorrentFilter))
 {
@@ -127,7 +130,7 @@ void TorrentFilter::update(Torrent::ChangeFlags changes)
 
     if (activity_type_ != Activity::ALL)
     {
-        static auto const activity_flags = std::map<Activity, Torrent::ChangeFlags>({
+        static constexpr auto ActivityFlags = std::array<std::pair<Activity, Torrent::ChangeFlags>, 7U>{ {
             { Activity::DOWNLOADING, Flag::ACTIVITY },
             { Activity::SEEDING, Flag::ACTIVITY },
             { Activity::ACTIVE, Flag::ACTIVE_PEER_COUNT | Flag::ACTIVITY },
@@ -135,10 +138,13 @@ void TorrentFilter::update(Torrent::ChangeFlags changes)
             { Activity::FINISHED, Flag::FINISHED },
             { Activity::VERIFYING, Flag::ACTIVITY },
             { Activity::ERROR, Flag::ERROR_CODE },
-        });
+        } };
 
-        auto const activity_flags_it = activity_flags.find(activity_type_);
-        refilter_needed = activity_flags_it != activity_flags.end() && changes.test(activity_flags_it->second);
+        auto const iter = std::find_if(
+            std::begin(ActivityFlags),
+            std::end(ActivityFlags),
+            [key = activity_type_](auto const& row) { return row.first == key; });
+        refilter_needed = iter != std::end(ActivityFlags) && changes.test(iter->second);
     }
 
     if (!refilter_needed)
diff --git a/gtk/TorrentSorter.cc b/gtk/TorrentSorter.cc
index b9cf9f890..106b635fc 100644
--- a/gtk/TorrentSorter.cc
+++ b/gtk/TorrentSorter.cc
@@ -13,6 +13,8 @@
 #include <libtransmission/utils.h>
 
 #include <algorithm>
+#include <array>
+#include <utility>
 
 using namespace std::string_view_literals;
 
@@ -178,7 +180,8 @@ TorrentSorter::TorrentSorter()
 
 void TorrentSorter::set_mode(std::string_view mode)
 {
-    static auto const compare_funcs = std::map<std::string_view, CompareFunc>({
+    static auto constexpr DefaultCompareFunc = &compare_by_name;
+    static auto constexpr CompareFuncs = std::array<std::pair<std::string_view, CompareFunc>, 9U>{ {
         { "sort-by-activity"sv, &compare_by_activity },
         { "sort-by-age"sv, &compare_by_age },
         { "sort-by-name"sv, &compare_by_name },
@@ -188,14 +191,13 @@ void TorrentSorter::set_mode(std::string_view mode)
         { "sort-by-size"sv, &compare_by_size },
         { "sort-by-state"sv, &compare_by_state },
         { "sort-by-time-left"sv, &compare_by_eta },
-    });
-
-    auto compare_func = &compare_by_name;
-    if (auto const compare_func_it = compare_funcs.find(mode); compare_func_it != compare_funcs.end())
-    {
-        compare_func = compare_func_it->second;
-    }
+    } };
 
+    auto const iter = std::find_if(
+        std::begin(CompareFuncs),
+        std::end(CompareFuncs),
+        [key = mode](auto const& row) { return row.first == key; });
+    auto const compare_func = iter != std::end(CompareFuncs) ? iter->second : DefaultCompareFunc;
     if (compare_func_ == compare_func)
     {
         return;
@@ -224,8 +226,7 @@ int TorrentSorter::compare(Torrent const& lhs, Torrent const& rhs) const
 void TorrentSorter::update(Torrent::ChangeFlags changes)
 {
     using Flag = Torrent::ChangeFlag;
-
-    static auto const compare_flags = std::map<CompareFunc, Torrent::ChangeFlags>({
+    static auto constexpr CompareFlags = std::array<std::pair<CompareFunc, Torrent::ChangeFlags>, 9U>{ {
         { &compare_by_activity, Flag::ACTIVE_PEER_COUNT | Flag::QUEUE_POSITION | Flag::SPEED_DOWN | Flag::SPEED_UP },
         { &compare_by_age, Flag::ADDED_DATE | Flag::NAME },
         { &compare_by_eta, Flag::ETA | Flag::NAME },
@@ -235,10 +236,13 @@ void TorrentSorter::update(Torrent::ChangeFlags changes)
         { &compare_by_ratio, Flag::QUEUE_POSITION | Flag::RATIO },
         { &compare_by_size, Flag::NAME | Flag::TOTAL_SIZE },
         { &compare_by_state, Flag::ACTIVITY | Flag::QUEUE_POSITION },
-    });
+    } };
 
-    if (auto const compare_flags_it = compare_flags.find(compare_func_);
-        compare_flags_it != compare_flags.end() && changes.test(compare_flags_it->second))
+    if (auto const iter = std::find_if(
+            std::begin(CompareFlags),
+            std::end(CompareFlags),
+            [key = compare_func_](auto const& row) { return row.first == key; });
+        iter != std::end(CompareFlags) && changes.test(iter->second))
     {
         changed(Change::DIFFERENT);
     }
diff --git a/libtransmission/log.cc b/libtransmission/log.cc
index 62f53233b..92115c928 100644
--- a/libtransmission/log.cc
+++ b/libtransmission/log.cc
@@ -8,7 +8,7 @@
 #include <chrono>
 #include <cstddef> // size_t
 #include <iterator> // back_insert_iterator, empty
-#include <map>
+#include <memory>
 #include <mutex>
 #include <optional>
 #include <string>
@@ -22,6 +22,8 @@
 #include <fmt/chrono.h>
 #include <fmt/core.h>
 
+#include <small/map.hpp>
+
 #include "libtransmission/file.h"
 #include "libtransmission/log.h"
 #include "libtransmission/tr-assert.h"
@@ -246,12 +248,12 @@ void tr_logAddMessage(char const* file, long line, tr_log_level level, std::stri
     auto const lock = log_state.unique_lock();
 
     // don't log the same warning ad infinitum.
-    // it's not useful after some point.
+    // at some point, it stops being useful.
     bool last_one = false;
     if (level == TR_LOG_CRITICAL || level == TR_LOG_ERROR || level == TR_LOG_WARN)
     {
         static auto constexpr MaxRepeat = size_t{ 30 };
-        static auto counts = new std::map<std::pair<std::string_view, int>, size_t>{};
+        static auto* const counts = new small::map<std::pair<std::string_view, long>, size_t>{};
 
         auto& count = (*counts)[std::make_pair(filename, line)];
         ++count;
@@ -267,12 +269,8 @@ void tr_logAddMessage(char const* file, long line, tr_log_level level, std::stri
     logAddImpl(filename, line, level, std::move(msg), name);
     if (last_one)
     {
-        logAddImpl(
-            filename,
-            line,
-            level,
-            _("Too many messages like this! I won't log this message anymore this session."),
-            name);
+        char const* final_msg = _("Too many messages like this! I won't log this message anymore this session.");
+        logAddImpl(filename, line, level, final_msg, name);
     }
 
     errno = err;
diff --git a/libtransmission/peer-mgr-wishlist.cc b/libtransmission/peer-mgr-wishlist.cc
index 96250e788..0a9993ffe 100644
--- a/libtransmission/peer-mgr-wishlist.cc
+++ b/libtransmission/peer-mgr-wishlist.cc
@@ -5,10 +5,11 @@
 
 #include <algorithm> // std::min, std::partial_sort
 #include <cstddef>
-#include <set>
 #include <utility>
 #include <vector>
 
+#include <small/set.hpp>
+
 #define LIBTRANSMISSION_PEER_MODULE
 
 #include "libtransmission/transmission.h"
@@ -136,11 +137,12 @@ std::vector<tr_block_span_t> Wishlist::next(size_t n_wanted_blocks)
 
     // We usually won't need all the candidates to be sorted until endgame, so don't
     // waste cycles sorting all of them here. partial sort is enough.
-    static auto constexpr MaxSortedPieces = size_t{ 30 };
+    static auto constexpr MaxSortedPieces = size_t{ 30U };
     auto const middle = std::min(std::size(candidates), MaxSortedPieces);
     std::partial_sort(std::begin(candidates), std::begin(candidates) + middle, std::end(candidates));
 
-    auto blocks = std::set<tr_block_index_t>{};
+    auto blocks = small::set<tr_block_index_t, 4096U>{};
+    blocks.reserve(n_wanted_blocks);
     for (auto const& candidate : candidates)
     {
         // do we have enough?
diff --git a/libtransmission/torrents.cc b/libtransmission/torrents.cc
index a4552c66a..d27e5bc27 100644
--- a/libtransmission/torrents.cc
+++ b/libtransmission/torrents.cc
@@ -5,7 +5,6 @@
 
 #include <algorithm>
 #include <ctime>
-#include <set>
 #include <string_view>
 #include <vector>
 
@@ -91,15 +90,18 @@ void tr_torrents::remove(tr_torrent const* tor, time_t current_time)
 
 std::vector<tr_torrent_id_t> tr_torrents::removedSince(time_t timestamp) const
 {
-    auto ids = std::set<tr_torrent_id_t>{};
+    auto ids = std::vector<tr_torrent_id_t>{};
+    ids.reserve(std::size(removed_));
 
     for (auto const& [id, removed_at] : removed_)
     {
         if (removed_at >= timestamp)
         {
-            ids.insert(id);
+            ids.emplace_back(id);
         }
     }
 
-    return { std::begin(ids), std::end(ids) };
+    std::sort(std::begin(ids), std::end(ids));
+    ids.erase(std::unique(std::begin(ids), std::end(ids)), std::end(ids));
+    return ids;
 }
diff --git a/libtransmission/utils.cc b/libtransmission/utils.cc
index c685b0840..5ba1d4190 100644
--- a/libtransmission/utils.cc
+++ b/libtransmission/utils.cc
@@ -493,18 +493,20 @@ std::vector<int> tr_num_parse_range(std::string_view str)
 {
     using namespace tr_num_parse_range_impl;
 
-    auto values = std::set<int>{};
+    auto values = std::vector<int>{};
     auto token = std::string_view{};
     auto range = number_range{};
     while (tr_strv_sep(&str, &token, ',') && parseNumberSection(token, range))
     {
         for (auto i = range.low; i <= range.high; ++i)
         {
-            values.insert(i);
+            values.emplace_back(i);
         }
     }
 
-    return { std::begin(values), std::end(values) };
+    std::sort(std::begin(values), std::end(values));
+    values.erase(std::unique(std::begin(values), std::end(values)), std::end(values));
+    return values;
 }
 
 // ---
diff --git a/qt/FileTreeItem.cc b/qt/FileTreeItem.cc
index 35e71bf02..5cc874cbd 100644
--- a/qt/FileTreeItem.cc
+++ b/qt/FileTreeItem.cc
@@ -5,9 +5,10 @@
 
 #include <algorithm>
 #include <cassert>
-#include <set>
 #include <utility>
 
+#include <small/set.hpp>
+
 #include <QApplication>
 #include <QStyle>
 
@@ -223,7 +224,7 @@ uint64_t FileTreeItem::size() const
 
 std::pair<int, int> FileTreeItem::update(QString const& name, bool wanted, int priority, uint64_t have_size, bool update_fields)
 {
-    auto changed_columns = std::set<int>{};
+    auto changed_columns = small::max_size_set<int, FileTreeModel::NUM_COLUMNS>{};
 
     if (name_ != name)
     {
diff --git a/qt/FileTreeModel.cc b/qt/FileTreeModel.cc
index ef45ced11..bd31a290f 100644
--- a/qt/FileTreeModel.cc
+++ b/qt/FileTreeModel.cc
@@ -7,10 +7,11 @@
 #include <cassert>
 #include <cstddef>
 #include <cstdint>
-#include <map>
 #include <memory>
 #include <set>
 
+#include <small/map.hpp>
+
 #include <libtransmission/transmission.h> // priorities
 
 #include <QAbstractItemModel>
@@ -470,7 +471,7 @@ void FileTreeModel::emitSubtreeChanged(QModelIndex const& idx, int first_column,
 
 void FileTreeModel::twiddleWanted(QModelIndexList const& indices)
 {
-    std::map<bool, QModelIndexList> wanted_indices;
+    auto wanted_indices = small::max_size_map<bool, QModelIndexList, 2U>{};
 
     for (QModelIndex const& i : getOrphanIndices(indices))
     {
@@ -489,7 +490,7 @@ void FileTreeModel::twiddleWanted(QModelIndexList const& indices)
 
 void FileTreeModel::twiddlePriority(QModelIndexList const& indices)
 {
-    std::map<int, QModelIndexList> priority_indices;
+    auto priority_indices = small::max_size_map<int, QModelIndexList, 8U>{};
 
     for (QModelIndex const& i : getOrphanIndices(indices))
     {
diff --git a/qt/FilterBar.cc b/qt/FilterBar.cc
index 44d5042e2..f1952c215 100644
--- a/qt/FilterBar.cc
+++ b/qt/FilterBar.cc
@@ -155,7 +155,7 @@ void FilterBar::refreshTrackers()
         return i;
     };
 
-    auto new_trackers = std::map<QString, int>(torrents_per_sitename.begin(), torrents_per_sitename.end());
+    auto new_trackers = small::map<QString, int>{ torrents_per_sitename.begin(), torrents_per_sitename.end() };
     auto old_it = sitename_counts_.cbegin();
     auto new_it = new_trackers.cbegin();
     auto const old_end = sitename_counts_.cend();
diff --git a/qt/FilterBar.h b/qt/FilterBar.h
index 4591f9785..0a5bf291e 100644
--- a/qt/FilterBar.h
+++ b/qt/FilterBar.h
@@ -6,7 +6,8 @@
 #pragma once
 
 #include <bitset>
-#include <map>
+
+#include <small/map.hpp>
 
 #include <QLineEdit>
 #include <QStandardItemModel>
@@ -63,7 +64,7 @@ private:
     FilterBarComboBox* const tracker_combo_ = createTrackerCombo(tracker_model_);
     QLineEdit* const line_edit_ = new QLineEdit{ this };
 
-    std::map<QString, int> sitename_counts_;
+    small::map<QString, int> sitename_counts_;
     QTimer recount_timer_;
     Pending pending_ = {};
     bool is_bootstrapping_ = {};
diff --git a/qt/OptionsDialog.h b/qt/OptionsDialog.h
index 741289d2a..b723be999 100644
--- a/qt/OptionsDialog.h
+++ b/qt/OptionsDialog.h
@@ -54,8 +54,6 @@ private slots:
     void onSessionUpdated();
 
 private:
-    using mybins_t = std::map<uint32_t, int32_t>;
-
     void reload();
     void updateWidgetsLocality();
     void clearInfo();
diff --git a/qt/Prefs.cc b/qt/Prefs.cc
index 47c738eff..5a8436003 100644
--- a/qt/Prefs.cc
+++ b/qt/Prefs.cc
@@ -201,6 +201,19 @@ bool isValidUtf8(QByteArray const& byteArray)
 #endif
 }
 
+[[nodiscard]] constexpr auto pref_is_savable(int pref)
+{
+    switch (pref)
+    {
+    // these are the prefs that don't get saved to settings.json
+    // when the application exits.
+    case Prefs::FILTER_TEXT:
+        return false;
+
+    default:
+        return true;
+    }
+}
 } // namespace
 
 /***
@@ -220,10 +233,6 @@ Prefs::Prefs(QString config_dir)
 
 #endif
 
-    // these are the prefs that don't get saved to settings.json
-    // when the application exits.
-    temporary_prefs_.insert(FILTER_TEXT);
-
     auto const app_defaults = get_default_app_settings();
     auto settings = tr_sessionLoadSettings(&app_defaults, config_dir_.toUtf8().constData(), nullptr);
     ensureSoundCommandIsAList(&settings);
@@ -323,7 +332,7 @@ Prefs::~Prefs()
 
     for (int i = 0; i < PREFS_COUNT; ++i)
     {
-        if (temporary_prefs_.count(i) != 0U)
+        if (!pref_is_savable(i))
         {
             continue;
         }
diff --git a/qt/Prefs.h b/qt/Prefs.h
index 01870734b..62bdb2d5a 100644
--- a/qt/Prefs.h
+++ b/qt/Prefs.h
@@ -204,7 +204,6 @@ private:
 
     QString const config_dir_;
 
-    std::set<int> temporary_prefs_;
     std::array<QVariant, PREFS_COUNT> mutable values_;
 
     static std::array<PrefItem, PREFS_COUNT> const Items;