From 5e99bace905663bf23e00f7107d09f27b1a8acc0 Mon Sep 17 00:00:00 2001
From: nenomius <nenomius@protonmail.com>
Date: Sat, 23 Jul 2022 00:52:11 +0300
Subject: [PATCH] Do less work when building completion trie

Convert to lower case only once per string.
---
 src/CompletionProxyModel.cpp | 67 ++++++++++++++++++------------------
 src/CompletionProxyModel.h   | 13 ++++++-
 2 files changed, 45 insertions(+), 35 deletions(-)

diff --git a/src/CompletionProxyModel.cpp b/src/CompletionProxyModel.cpp
index 07ecdf72..5712cd30 100644
--- a/src/CompletionProxyModel.cpp
+++ b/src/CompletionProxyModel.cpp
@@ -22,54 +22,53 @@ CompletionProxyModel::CompletionProxyModel(QAbstractItemModel *model,
 {
     setSourceModel(model);
 
-    // insert all the full texts
+    auto insertParts = [this](const QString &str, int id) {
+        QTextBoundaryFinder finder(QTextBoundaryFinder::BoundaryType::Word, str);
+        finder.toStart();
+        do {
+            auto start = finder.position();
+            finder.toNextBoundary();
+            auto end = finder.position();
+
+            auto ref = str.midRef(start, end - start).trimmed();
+            if (!ref.isEmpty())
+                trie_.insert<ElementRank::second>(ref.toUcs4(), id);
+        } while (finder.position() < str.size());
+    };
+
+    const auto start_at = std::chrono::steady_clock::now();
+
+    // insert full texts and partial matches
     for (int i = 0; i < sourceModel()->rowCount(); i++) {
-        if (static_cast<size_t>(i) < max_completions_)
-            mapping.push_back(i);
+        // full texts are ranked first and partial matches second
+        // that way when searching full texts will be first in result list
 
         auto string1 = sourceModel()
                          ->data(sourceModel()->index(i, 0), CompletionModel::SearchRole)
                          .toString()
                          .toLower();
-        if (!string1.isEmpty())
-            trie_.insert(string1.toUcs4(), i);
+        if (!string1.isEmpty()) {
+            trie_.insert<ElementRank::first>(string1.toUcs4(), i);
+            insertParts(string1, i);
+        }
 
         auto string2 = sourceModel()
                          ->data(sourceModel()->index(i, 0), CompletionModel::SearchRole2)
                          .toString()
                          .toLower();
-        if (!string2.isEmpty())
-            trie_.insert(string2.toUcs4(), i);
+        if (!string2.isEmpty()) {
+            trie_.insert<ElementRank::first>(string2.toUcs4(), i);
+            insertParts(string2, i);
+        }
     }
 
-    // insert the partial matches
-    for (int i = 0; i < sourceModel()->rowCount(); i++) {
-        auto insertParts = [i, this](const QString &str) {
-            if (str.isEmpty())
-                return;
+    const auto end_at     = std::chrono::steady_clock::now();
+    const auto build_time = std::chrono::duration<double, std::milli>(end_at - start_at);
+    nhlog::ui()->debug("CompletionProxyModel: build trie: {} ms", build_time.count());
 
-            QTextBoundaryFinder finder(QTextBoundaryFinder::BoundaryType::Word, str);
-            finder.toStart();
-            do {
-                auto start = finder.position();
-                finder.toNextBoundary();
-                auto end = finder.position();
-
-                auto ref = str.midRef(start, end - start).trimmed();
-                if (!ref.isEmpty())
-                    trie_.insert(ref.toUcs4(), i);
-            } while (finder.position() < str.size());
-        };
-
-        insertParts(sourceModel()
-                      ->data(sourceModel()->index(i, 0), CompletionModel::SearchRole)
-                      .toString()
-                      .toLower());
-        insertParts(sourceModel()
-                      ->data(sourceModel()->index(i, 0), CompletionModel::SearchRole2)
-                      .toString()
-                      .toLower());
-    }
+    // initialize default mapping
+    mapping.resize(std::min(max_completions_, static_cast<size_t>(model->rowCount())));
+    std::iota(mapping.begin(), mapping.end(), 0);
 
     connect(
       this,
diff --git a/src/CompletionProxyModel.h b/src/CompletionProxyModel.h
index 78c7ea5f..e4a1b9cd 100644
--- a/src/CompletionProxyModel.h
+++ b/src/CompletionProxyModel.h
@@ -9,12 +9,19 @@
 
 #include <QAbstractProxyModel>
 
+enum class ElementRank
+{
+    first,
+    second
+};
+
 template<typename Key, typename Value>
 struct trie
 {
     std::vector<Value> values;
     std::map<Key, trie> next;
 
+    template<ElementRank r>
     void insert(const QVector<Key> &keys, const Value &v)
     {
         auto t = this;
@@ -22,7 +29,11 @@ struct trie
             t = &t->next[k];
         }
 
-        t->values.push_back(v);
+        if constexpr (r == ElementRank::first) {
+            t->values.insert(t->values.begin(), v);
+        } else if constexpr (r == ElementRank::second) {
+            t->values.push_back(v);
+        }
     }
 
     std::vector<Value> valuesAndSubvalues(size_t limit = -1) const