AK: Make quick_sort() a little more ergonomic

Now it actually defaults to "a < b" comparison, instead of forcing you
to provide a trivial less-than comparator. Also you can pass in any
collection type that has .begin() and .end() and we'll sort it for you.

AK/QuickSort.h

@@ -30,14 +30,8 @@
 
 namespace AK {
 
-template<typename T>
-bool is_less_than(const T& a, const T& b)
-{
-    return a < b;
-}
-
 template<typename Iterator, typename LessThan>
-void quick_sort(Iterator start, Iterator end, LessThan less_than = is_less_than)
+void quick_sort(Iterator start, Iterator end, LessThan less_than)
 {
     int size = end - start;
     if (size <= 1)
@@ -62,6 +56,24 @@ void quick_sort(Iterator start, Iterator end, LessThan less_than = is_less_than)
     quick_sort(start + i, end, less_than);
 }
 
+template<typename Iterator>
+void quick_sort(Iterator start, Iterator end)
+{
+    quick_sort(start, end, [](auto& a, auto& b) { return a < b; });
+}
+
+template<typename Collection, typename LessThan>
+void quick_sort(Collection& collection, LessThan less_than)
+{
+    quick_sort(collection.begin(), collection.end(), move(less_than));
+}
+
+template<typename Collection>
+void quick_sort(Collection& collection)
+{
+    quick_sort(collection.begin(), collection.end());
+}
+
 }
 
 using AK::quick_sort;

Applications/IRCClient/IRCClient.cpp

@@ -542,7 +542,7 @@ void IRCClient::handle_rpl_namreply(const Message& msg)
     auto& channel = ensure_channel(channel_name);
     auto members = msg.arguments[3].split(' ');
 
-    quick_sort(members.begin(), members.end(), [](auto& a, auto& b) {
+    quick_sort(members, [](auto& a, auto& b) {
         return strcasecmp(a.characters(), b.characters()) < 0;
     });
 

Applications/SystemMenu/main.cpp

@@ -123,7 +123,7 @@ NonnullRefPtr<GUI::Menu> build_system_menu()
     Vector<String> sorted_app_categories;
     for (auto& category : seen_app_categories)
         sorted_app_categories.append(category);
-    quick_sort(sorted_app_categories.begin(), sorted_app_categories.end(), [](auto& a, auto& b) { return a < b; });
+    quick_sort(sorted_app_categories);
 
     u8 system_menu_name[] = { 0xc3, 0xb8, 0 };
     auto system_menu = GUI::Menu::construct(String((const char*)system_menu_name));
@@ -175,7 +175,7 @@ NonnullRefPtr<GUI::Menu> build_system_menu()
             auto theme_path = String::format("/res/themes/%s", theme_name.characters());
             g_themes.append({ FileSystemPath(theme_name).title(), theme_path });
         }
-        quick_sort(g_themes.begin(), g_themes.end(), [](auto& a, auto& b) { return a.name < b.name; });
+        quick_sort(g_themes, [](auto& a, auto& b) { return a.name < b.name; });
     }
 
     {

DevTools/HackStudio/Project.cpp

@@ -60,7 +60,7 @@ struct Project::ProjectTreeNode : public RefCounted<ProjectTreeNode> {
     {
         if (type == Type::File)
             return;
-        quick_sort(children.begin(), children.end(), [](auto& a, auto& b) {
+        quick_sort(children, [](auto& a, auto& b) {
             return a->name < b->name;
         });
         for (auto& child : children)

Kernel/Scheduler.cpp

@@ -401,7 +401,7 @@ bool Scheduler::pick_next()
         sorted_runnables.append(&thread);
         return IterationDecision::Continue;
     });
-    quick_sort(sorted_runnables.begin(), sorted_runnables.end(), [](auto& a, auto& b) { return a->effective_priority() >= b->effective_priority(); });
+    quick_sort(sorted_runnables, [](auto& a, auto& b) { return a->effective_priority() >= b->effective_priority(); });
 
     Thread* thread_to_schedule = nullptr;
 

Libraries/LibELF/ELFLoader.cpp

@@ -179,7 +179,7 @@ String ELFLoader::symbolicate(u32 address, u32* out_offset) const
             m_sorted_symbols.append({ symbol.value(), symbol.name() });
             return IterationDecision::Continue;
         });
-        quick_sort(m_sorted_symbols.begin(), m_sorted_symbols.end(), [](auto& a, auto& b) {
+        quick_sort(m_sorted_symbols, [](auto& a, auto& b) {
             return a.address < b.address;
         });
     }

Libraries/LibGUI/FontDatabase.cpp

@@ -71,7 +71,7 @@ void GFontDatabase::for_each_font(Function<void(const StringView&)> callback)
     names.ensure_capacity(m_name_to_metadata.size());
     for (auto& it : m_name_to_metadata)
         names.append(it.key);
-    quick_sort(names.begin(), names.end(), AK::is_less_than<String>);
+    quick_sort(names);
     for (auto& name : names)
         callback(name);
 }
@@ -84,7 +84,7 @@ void GFontDatabase::for_each_fixed_width_font(Function<void(const StringView&)>
         if (it.value.is_fixed_width)
             names.append(it.key);
     }
-    quick_sort(names.begin(), names.end(), AK::is_less_than<String>);
+    quick_sort(names);
     for (auto& name : names)
         callback(name);
 }

Libraries/LibGUI/SortingProxyModel.cpp

@@ -121,7 +121,7 @@ void SortingProxyModel::resort()
         did_update();
         return;
     }
-    quick_sort(m_row_mappings.begin(), m_row_mappings.end(), [&](auto row1, auto row2) -> bool {
+    quick_sort(m_row_mappings, [&](auto row1, auto row2) -> bool {
         auto data1 = target().data(target().index(row1, m_key_column), Model::Role::Sort);
         auto data2 = target().data(target().index(row2, m_key_column), Model::Role::Sort);
         if (data1 == data2)

Servers/WindowServer/AppletManager.cpp

@@ -71,7 +71,7 @@ void AppletManager::add_applet(Window& applet)
 {
     m_applets.append(applet.make_weak_ptr());
 
-    quick_sort(m_applets.begin(), m_applets.end(), [](auto& a, auto& b) {
+    quick_sort(m_applets, [](auto& a, auto& b) {
         auto index_a = order_vector.find_first_index(a->title());
         auto index_b = order_vector.find_first_index(b->title());
         ASSERT(index_a.has_value());

Shell/LineEditor.cpp

@@ -127,7 +127,7 @@ void LineEditor::cache_path()
         }
     }
 
-    quick_sort(m_path.begin(), m_path.end(), AK::is_less_than<String>);
+    quick_sort(m_path);
 }
 
 void LineEditor::cut_mismatching_chars(String& completion, const String& other, size_t start_compare)

Userland/cut.cpp

@@ -221,7 +221,7 @@ int main(int argc, char** argv)
 
     Vector<Index> byte_vector;
     expand_list(tokens, byte_vector);
-    quick_sort(byte_vector.begin(), byte_vector.end(), [](auto& a, auto& b) { return a.m_from < b.m_from; });
+    quick_sort(byte_vector, [](auto& a, auto& b) { return a.m_from < b.m_from; });
     /* Process each file */
     for (auto& file : files) {
         cut_file(file, byte_vector);

Userland/ls.cpp

@@ -326,7 +326,7 @@ int do_file_system_object_long(const char* path)
         files.append(move(metadata));
     }
 
-    quick_sort(files.begin(), files.end(), [](auto& a, auto& b) {
+    quick_sort(files, [](auto& a, auto& b) {
         if (flag_sort_by_timestamp) {
             if (flag_reverse_sort)
                 return a.stat.st_mtime > b.stat.st_mtime;
@@ -382,7 +382,7 @@ int do_file_system_object_short(const char* path)
         if (names.last().length() > longest_name)
             longest_name = name.length();
     }
-    quick_sort(names.begin(), names.end(), [](auto& a, auto& b) { return a < b; });
+    quick_sort(names);
 
     size_t printed_on_row = 0;
     size_t nprinted = 0;

Userland/sort.cpp

@@ -50,7 +50,7 @@ int main(int argc, char** argv)
         lines.append(buffer);
     }
 
-    quick_sort(lines.begin(), lines.end(), [](auto& a, auto& b) {
+    quick_sort(lines, [](auto& a, auto& b) {
         return strcmp(a.characters(), b.characters()) < 0;
     });
 

Userland/top.cpp

@@ -184,7 +184,7 @@ int main(int, char**)
             threads.append(&it.value);
         }
 
-        quick_sort(threads.begin(), threads.end(), [](auto* p1, auto* p2) {
+        quick_sort(threads, [](auto* p1, auto* p2) {
             return p2->times_scheduled_since_prev < p1->times_scheduled_since_prev;
         });