Vector: Implement find, find_if, find_first_matching in terms of AK::find*

Problem:
- The implementation of `find` is coupled to the implementation of `Vector`.
- `Vector::find` takes the predicate by value which might be expensive.

Solution:
- Decouple the implementation of `find` from `Vector` by using a
  generic `find` algorithm.
- Change the name of `find` with a predicate to `find_if` so that a
  binding reference can be used and the predicate can be forwarded to
  avoid copies.
- Change all the `find(pred)` call sites to use `find_if`.

AK/Tests/TestVector.cpp

@@ -394,4 +394,30 @@ TEST_CASE(should_compare_vectors_of_different_sizes)
     EXPECT(a != b);
 }
 
+TEST_CASE(should_find_value)
+{
+    AK::Vector<int> v { 1, 2, 3, 4, 0, 6, 7, 8, 0, 0 };
+
+    const auto expected = v.begin() + 4;
+
+    EXPECT_EQ(expected, v.find(0));
+}
+
+TEST_CASE(should_find_predicate)
+{
+    AK::Vector<int> v { 1, 2, 3, 4, 0, 6, 7, 8, 0, 0 };
+
+    const auto expected = v.begin() + 4;
+
+    EXPECT_EQ(expected, v.find_if([](const auto v) { return v == 0; }));
+}
+
+TEST_CASE(should_find_index)
+{
+    AK::Vector<int> v { 1, 2, 3, 4, 0, 6, 7, 8, 0, 0 };
+
+    EXPECT_EQ(4u, v.find_first_index(0).value());
+    EXPECT(!v.find_first_index(42).has_value());
+}
+
 TEST_MAIN(Vector)

AK/Vector.h

@@ -27,6 +27,7 @@
 #pragma once
 
 #include <AK/Assertions.h>
+#include <AK/Find.h>
 #include <AK/Forward.h>
 #include <AK/Iterator.h>
 #include <AK/Optional.h>
@@ -538,41 +539,33 @@ public:
     ConstIterator end() const { return ConstIterator::end(*this); }
     Iterator end() { return Iterator::end(*this); }
 
-    template<typename Finder>
-    ConstIterator find(Finder finder) const
+    template<typename TUnaryPredicate>
+    ConstIterator find_if(TUnaryPredicate&& finder) const
     {
-        for (size_t i = 0; i < m_size; ++i) {
-            if (finder(at(i)))
-                return ConstIterator(*this, i);
-        }
-        return end();
+        return AK::find_if(begin(), end(), forward<TUnaryPredicate>(finder));
     }
 
-    template<typename Finder>
-    Iterator find(Finder finder)
+    template<typename TUnaryPredicate>
+    Iterator find_if(TUnaryPredicate&& finder)
     {
-        for (size_t i = 0; i < m_size; ++i) {
-            if (finder(at(i)))
-                return Iterator { *this, i };
-        }
-        return end();
+        return AK::find_if(begin(), end(), forward<TUnaryPredicate>(finder));
     }
 
     ConstIterator find(const T& value) const
     {
-        return find([&](auto& other) { return Traits<T>::equals(value, other); });
+        return AK::find(begin(), end(), value);
     }
 
     Iterator find(const T& value)
     {
-        return find([&](auto& other) { return Traits<T>::equals(value, other); });
+        return AK::find(begin(), end(), value);
     }
 
     Optional<size_t> find_first_index(const T& value)
     {
-        for (size_t i = 0; i < m_size; ++i) {
-            if (Traits<T>::equals(value, at(i)))
-                return i;
+        if (const auto index = AK::find_index(begin(), end(), value);
+            index < size()) {
+            return index;
         }
         return {};
     }

Applications/Spreadsheet/Cell.cpp

@@ -187,7 +187,7 @@ void Cell::reference_from(Cell* other)
     if (!other || other == this)
         return;
 
-    if (!m_referencing_cells.find([other](auto& ptr) { return ptr.ptr() == other; }).is_end())
+    if (!m_referencing_cells.find_if([other](const auto& ptr) { return ptr.ptr() == other; }).is_end())
         return;
 
     m_referencing_cells.append(other->make_weak_ptr());

Applications/Spreadsheet/Readers/XSV.cpp

@@ -244,7 +244,7 @@ XSV::Field XSV::read_one_unquoted_field()
 StringView XSV::Row::operator[](StringView name) const
 {
     ASSERT(!m_xsv.m_names.is_empty());
-    auto it = m_xsv.m_names.find([&](auto&& entry) { return name == entry; });
+    auto it = m_xsv.m_names.find_if([&](const auto& entry) { return name == entry; });
     ASSERT(!it.is_end());
 
     return (*this)[it.index()];

Applications/SystemMonitor/DevicesModel.cpp

@@ -182,7 +182,7 @@ void DevicesModel::update()
             unsigned _major = major(statbuf.st_rdev);
             unsigned _minor = minor(statbuf.st_rdev);
 
-            auto it = m_devices.find([_major, _minor](auto& device_info) {
+            auto it = m_devices.find_if([_major, _minor](const auto& device_info) {
                 return device_info.major == _major && device_info.minor == _minor;
             });
             if (it != m_devices.end()) {

DevTools/HackStudio/Debugger/VariablesModel.cpp

@@ -80,7 +80,7 @@ static String variable_value_as_string(const Debug::DebugInfo::VariableInfo& var
     if (variable.is_enum_type()) {
         auto value = Debugger::the().session()->peek((u32*)variable_address);
         ASSERT(value.has_value());
-        auto it = variable.type->members.find([enumerator_value = value.value()](auto& enumerator) {
+        auto it = variable.type->members.find_if([&enumerator_value = value.value()](const auto& enumerator) {
             return enumerator->constant_data.as_u32 == enumerator_value;
         });
         ASSERT(!it.is_end());
@@ -116,7 +116,7 @@ static Optional<u32> string_to_variable_value(const StringView& string_value, co
         if (string_value.starts_with(prefix_string))
             string_to_use = string_value.substring_view(prefix_string.length(), string_value.length() - prefix_string.length());
 
-        auto it = variable.type->members.find([string_to_use](auto& enumerator) {
+        auto it = variable.type->members.find_if([string_to_use](const auto& enumerator) {
             return enumerator->name == string_to_use;
         });
 

Libraries/LibCore/ArgsParser.cpp

@@ -109,7 +109,7 @@ bool ArgsParser::parse(int argc, char** argv, bool exit_on_failure)
             index_of_found_long_option = -1;
         } else {
             // It was a short option, look it up.
-            auto it = m_options.find([c](auto& opt) { return c == opt.short_name; });
+            auto it = m_options.find_if([c](auto& opt) { return c == opt.short_name; });
             ASSERT(!it.is_end());
             found_option = &*it;
         }

Libraries/LibMarkdown/Text.cpp

@@ -69,7 +69,7 @@ String Text::render_to_html() const
             { "b", &Style::strong },
             { "code", &Style::code }
         };
-        auto it = open_tags.find([&](const String& open_tag) {
+        auto it = open_tags.find_if([&](const String& open_tag) {
             if (open_tag == "a" && current_style.href != span.style.href)
                 return true;
             if (open_tag == "img" && current_style.img != span.style.img)

Libraries/LibTLS/ClientHandshake.cpp

@@ -398,7 +398,7 @@ ssize_t TLSv12::handle_payload(ReadonlyBytes vbuffer)
                 }
                 payload_res = handle_certificate(buffer.slice(1, payload_size));
                 if (m_context.certificates.size()) {
-                    auto it = m_context.certificates.find([&](auto& cert) { return cert.is_valid(); });
+                    auto it = m_context.certificates.find_if([](const auto& cert) { return cert.is_valid(); });
 
                     if (it.is_end()) {
                         // no valid certificates

Services/WindowServer/MenuManager.cpp

@@ -162,7 +162,7 @@ void MenuManager::event(Core::Event& event)
         if (event.type() == Event::KeyDown) {
 
             if (key_event.key() == Key_Left) {
-                auto it = m_open_menu_stack.find([&](auto& other) { return m_current_menu == other.ptr(); });
+                auto it = m_open_menu_stack.find_if([&](const auto& other) { return m_current_menu == other.ptr(); });
                 ASSERT(!it.is_end());
 
                 // Going "back" a menu should be the previous menu in the stack
@@ -390,7 +390,7 @@ void MenuManager::open_menu(Menu& menu, bool as_current_menu)
         menu.menu_window()->set_visible(true);
     }
 
-    if (m_open_menu_stack.find([&menu](auto& other) { return &menu == other.ptr(); }).is_end())
+    if (m_open_menu_stack.find_if([&menu](auto& other) { return &menu == other.ptr(); }).is_end())
         m_open_menu_stack.append(menu);
 
     if (as_current_menu || !current_menu()) {