LibLine: Add support for user-controlled masking

Userland/Libraries/LibLine/Editor.cpp

@@ -12,6 +12,7 @@
 #include <AK/GenericLexer.h>
 #include <AK/JsonObject.h>
 #include <AK/MemoryStream.h>
+#include <AK/RedBlackTree.h>
 #include <AK/ScopeGuard.h>
 #include <AK/ScopedValueRollback.h>
 #include <AK/StringBuilder.h>
@@ -475,6 +476,27 @@ void Editor::stylize(Span const& span, Style const& style)
         end = offsets.end;
     }
 
+    if (auto maybe_mask = style.mask(); maybe_mask.has_value()) {
+        auto it = m_current_masks.find_smallest_not_below_iterator(span.beginning());
+        Optional<Style::Mask> last_encountered_entry;
+        if (!it.is_end()) {
+            // Delete all overlapping old masks.
+            while (true) {
+                auto next_it = m_current_masks.find_largest_not_above_iterator(span.end());
+                if (next_it.is_end())
+                    break;
+                if (it->has_value())
+                    last_encountered_entry = *it;
+                m_current_masks.remove(next_it.key());
+            }
+        }
+        m_current_masks.insert(span.beginning(), move(maybe_mask));
+        m_current_masks.insert(span.end(), {});
+        if (last_encountered_entry.has_value())
+            m_current_masks.insert(span.end() + 1, move(last_encountered_entry));
+        style.unset_mask();
+    }
+
     auto& spans_starting = style.is_anchored() ? m_current_spans.m_anchored_spans_starting : m_current_spans.m_spans_starting;
     auto& spans_ending = style.is_anchored() ? m_current_spans.m_anchored_spans_ending : m_current_spans.m_spans_ending;
 
@@ -1272,7 +1294,7 @@ void Editor::recalculate_origin()
 }
 void Editor::cleanup()
 {
-    auto current_buffer_metrics = actual_rendered_string_metrics(buffer_view());
+    auto current_buffer_metrics = actual_rendered_string_metrics(buffer_view(), m_current_masks);
     auto new_lines = current_prompt_metrics().lines_with_addition(current_buffer_metrics, m_num_columns);
     auto shown_lines = num_lines();
     if (new_lines < shown_lines)
@@ -1335,7 +1357,7 @@ void Editor::refresh_display()
     if (m_cached_prompt_valid && !m_refresh_needed && m_pending_chars.size() == 0) {
         // Probably just moving around.
         reposition_cursor(output_stream);
-        m_cached_buffer_metrics = actual_rendered_string_metrics(buffer_view());
+        m_cached_buffer_metrics = actual_rendered_string_metrics(buffer_view(), m_current_masks);
         m_drawn_end_of_line_offset = m_buffer.size();
         return;
     }
@@ -1351,7 +1373,7 @@ void Editor::refresh_display()
             m_pending_chars.clear();
             m_drawn_cursor = m_cursor;
             m_drawn_end_of_line_offset = m_buffer.size();
-            m_cached_buffer_metrics = actual_rendered_string_metrics(buffer_view());
+            m_cached_buffer_metrics = actual_rendered_string_metrics(buffer_view(), m_current_masks);
             m_drawn_spans = m_current_spans;
             return;
         }
@@ -1395,8 +1417,27 @@ void Editor::refresh_display()
     };
 
     auto print_character_at = [&](size_t i) {
+        Variant<u32, Utf8View> c { Utf8View {} };
+        if (auto it = m_current_masks.find_largest_not_above_iterator(i); !it.is_end() && it->has_value()) {
+            auto offset = i - it.key();
+            if (it->value().mode == Style::Mask::Mode::ReplaceEntireSelection) {
+                auto& mask = it->value().replacement_view;
+                auto replacement = mask.begin().peek(offset);
+                if (!replacement.has_value())
+                    return;
+                c = replacement.value();
+                ++it;
+                u32 next_offset = it.is_end() ? m_drawn_end_of_line_offset : it.key();
+                if (i + 1 == next_offset)
+                    c = mask.unicode_substring_view(offset, mask.length() - offset);
+            } else {
+                c = it->value().replacement_view;
+            }
+        } else {
+            c = m_buffer[i];
+        }
+        auto print_single_character = [&](auto c) {
             StringBuilder builder;
-        auto c = m_buffer[i];
             bool should_print_masked = is_ascii_control(c) && c != '\n';
             bool should_print_caret = c < 64 && should_print_masked;
             if (should_print_caret)
@@ -1414,6 +1455,10 @@ void Editor::refresh_display()
             if (should_print_masked)
                 output_stream.write("\033[27m"sv.bytes());
         };
+        c.visit(
+            [&](u32 c) { print_single_character(c); },
+            [&](auto& view) { for (auto c : view) print_single_character(c); });
+    };
 
     // If there have been no changes to previous sections of the line (style or text)
     // just append the new text with the appropriate styles.
@@ -1429,7 +1474,7 @@ void Editor::refresh_display()
         VT::apply_style(Style::reset_style(), output_stream);
         m_pending_chars.clear();
         m_refresh_needed = false;
-        m_cached_buffer_metrics = actual_rendered_string_metrics(buffer_view());
+        m_cached_buffer_metrics = actual_rendered_string_metrics(buffer_view(), m_current_masks);
         m_chars_touched_in_the_middle = 0;
         m_drawn_cursor = m_cursor;
         m_drawn_end_of_line_offset = m_buffer.size();
@@ -1477,7 +1522,7 @@ void Editor::refresh_display()
 
     m_pending_chars.clear();
     m_refresh_needed = false;
-    m_cached_buffer_metrics = actual_rendered_string_metrics(buffer_view());
+    m_cached_buffer_metrics = actual_rendered_string_metrics(buffer_view(), m_current_masks);
     m_chars_touched_in_the_middle = 0;
     m_drawn_spans = m_current_spans;
     m_drawn_end_of_line_offset = m_buffer.size();
@@ -1490,6 +1535,8 @@ void Editor::strip_styles(bool strip_anchored)
 {
     m_current_spans.m_spans_starting.clear();
     m_current_spans.m_spans_ending.clear();
+    m_current_masks.clear();
+    m_cached_buffer_metrics = actual_rendered_string_metrics(buffer_view(), {});
 
     if (strip_anchored) {
         m_current_spans.m_anchored_spans_starting.clear();
@@ -1662,6 +1709,14 @@ String Style::to_string() const
     if (!m_hyperlink.is_empty())
         builder.appendff("Hyperlink(\"{}\"), ", m_hyperlink.m_link);
 
+    if (!m_mask.has_value()) {
+        builder.appendff("Mask(\"{}\", {}), ",
+            m_mask->replacement,
+            m_mask->mode == Mask::Mode::ReplaceEntireSelection
+                ? "ReplaceEntireSelection"
+                : "ReplaceEachCodePointInSelection");
+    }
+
     builder.append("}");
 
     return builder.build();
@@ -1715,20 +1770,77 @@ void VT::clear_to_end_of_line(OutputStream& stream)
     stream.write("\033[K"sv.bytes());
 }
 
-StringMetrics Editor::actual_rendered_string_metrics(StringView string)
+enum VTState {
+    Free = 1,
+    Escape = 3,
+    Bracket = 5,
+    BracketArgsSemi = 7,
+    Title = 9,
+};
+static VTState actual_rendered_string_length_step(StringMetrics& metrics, size_t index, StringMetrics::LineMetrics& current_line, u32 c, u32 next_c, VTState state, Optional<Style::Mask> const& mask);
+
+enum class MaskedSelectionDecision {
+    Skip,
+    Continue,
+};
+static MaskedSelectionDecision resolve_masked_selection(Optional<Style::Mask>& mask, size_t& i, auto& mask_it, auto& view, auto& state, auto& metrics, auto& current_line)
+{
+    if (mask.has_value() && mask->mode == Style::Mask::Mode::ReplaceEntireSelection) {
+        ++mask_it;
+        auto actual_end_offset = mask_it.is_end() ? view.length() : mask_it.key();
+        auto end_offset = min(actual_end_offset, view.length());
+        size_t j = 0;
+        for (auto it = mask->replacement_view.begin(); it != mask->replacement_view.end(); ++it) {
+            auto it_copy = it;
+            ++it_copy;
+            auto next_c = it_copy == mask->replacement_view.end() ? 0 : *it_copy;
+            state = actual_rendered_string_length_step(metrics, j, current_line, *it, next_c, state, {});
+            ++j;
+            if (j <= actual_end_offset - i && j + i >= view.length())
+                break;
+        }
+        current_line.masked_chars.empend(i, end_offset - i, j);
+        i = end_offset;
+
+        if (mask_it.is_end())
+            mask = {};
+        else
+            mask = *mask_it;
+        return MaskedSelectionDecision::Skip;
+    }
+    return MaskedSelectionDecision::Continue;
+}
+
+StringMetrics Editor::actual_rendered_string_metrics(StringView string, RedBlackTree<u32, Optional<Style::Mask>> const& masks)
 {
     StringMetrics metrics;
     StringMetrics::LineMetrics current_line;
     VTState state { Free };
     Utf8View view { string };
     auto it = view.begin();
+    Optional<Style::Mask> mask;
+    size_t i = 0;
+    auto mask_it = masks.begin();
 
     for (; it != view.end(); ++it) {
+        if (!mask_it.is_end() && mask_it.key() <= i)
+            mask = *mask_it;
         auto c = *it;
         auto it_copy = it;
         ++it_copy;
+
+        if (resolve_masked_selection(mask, i, mask_it, view, state, metrics, current_line) == MaskedSelectionDecision::Skip)
+            continue;
+
         auto next_c = it_copy == view.end() ? 0 : *it_copy;
-        state = actual_rendered_string_length_step(metrics, view.iterator_offset(it), current_line, c, next_c, state);
+        state = actual_rendered_string_length_step(metrics, view.iterator_offset(it), current_line, c, next_c, state, mask);
+        if (!mask_it.is_end() && mask_it.key() <= i) {
+            auto mask_it_peek = mask_it;
+            ++mask_it_peek;
+            if (!mask_it_peek.is_end() && mask_it_peek.key() > i)
+                mask_it = mask_it_peek;
+        }
+        ++i;
     }
 
     metrics.line_metrics.append(current_line);
@@ -1739,16 +1851,33 @@ StringMetrics Editor::actual_rendered_string_metrics(StringView string)
     return metrics;
 }
 
-StringMetrics Editor::actual_rendered_string_metrics(Utf32View const& view)
+StringMetrics Editor::actual_rendered_string_metrics(Utf32View const& view, RedBlackTree<u32, Optional<Style::Mask>> const& masks)
 {
     StringMetrics metrics;
     StringMetrics::LineMetrics current_line;
     VTState state { Free };
+    Optional<Style::Mask> mask;
+
+    auto mask_it = masks.begin();
 
     for (size_t i = 0; i < view.length(); ++i) {
-        auto c = view.code_points()[i];
+        auto c = view[i];
+        if (!mask_it.is_end() && mask_it.key() <= i)
+            mask = *mask_it;
+
+        if (resolve_masked_selection(mask, i, mask_it, view, state, metrics, current_line) == MaskedSelectionDecision::Skip) {
+            --i;
+            continue;
+        }
+
         auto next_c = i + 1 < view.length() ? view.code_points()[i + 1] : 0;
-        state = actual_rendered_string_length_step(metrics, i, current_line, c, next_c, state);
+        state = actual_rendered_string_length_step(metrics, i, current_line, c, next_c, state, mask);
+        if (!mask_it.is_end() && mask_it.key() <= i) {
+            auto mask_it_peek = mask_it;
+            ++mask_it_peek;
+            if (!mask_it_peek.is_end() && mask_it_peek.key() > i)
+                mask_it = mask_it_peek;
+        }
     }
 
     metrics.line_metrics.append(current_line);
@@ -1759,10 +1888,10 @@ StringMetrics Editor::actual_rendered_string_metrics(Utf32View const& view)
     return metrics;
 }
 
-Editor::VTState Editor::actual_rendered_string_length_step(StringMetrics& metrics, size_t index, StringMetrics::LineMetrics& current_line, u32 c, u32 next_c, VTState state)
+VTState actual_rendered_string_length_step(StringMetrics& metrics, size_t index, StringMetrics::LineMetrics& current_line, u32 c, u32 next_c, VTState state, Optional<Style::Mask> const& mask)
 {
     switch (state) {
-    case Free:
+    case Free: {
         if (c == '\x1b') { // escape
             return Escape;
         }
@@ -1779,12 +1908,26 @@ Editor::VTState Editor::actual_rendered_string_length_step(StringMetrics& metric
             current_line.length = 0;
             return state;
         }
-        if (is_ascii_control(c) && c != '\n')
+        auto is_control = is_ascii_control(c);
+        if (is_control) {
+            if (mask.has_value())
+                current_line.masked_chars.append({ index, 1, mask->replacement_view.length() });
+            else
                 current_line.masked_chars.append({ index, 1, c < 64 ? 2u : 4u }); // if the character cannot be represented as ^c, represent it as \xbb.
+        }
         // FIXME: This will not support anything sophisticated
+        if (mask.has_value()) {
+            current_line.length += mask->replacement_view.length();
+            metrics.total_length += mask->replacement_view.length();
+        } else if (is_control) {
+            current_line.length += current_line.masked_chars.last().masked_length;
+            metrics.total_length += current_line.masked_chars.last().masked_length;
+        } else {
             ++current_line.length;
             ++metrics.total_length;
+        }
         return state;
+    }
     case Escape:
         if (c == ']') {
             if (next_c == '0')

Userland/Libraries/LibLine/Editor.h

@@ -12,6 +12,7 @@
 #include <AK/Function.h>
 #include <AK/HashMap.h>
 #include <AK/OwnPtr.h>
+#include <AK/RedBlackTree.h>
 #include <AK/Result.h>
 #include <AK/String.h>
 #include <AK/Traits.h>
@@ -159,8 +160,8 @@ public:
     void register_key_input_callback(Vector<Key> keys, Function<bool(Editor&)> callback) { m_callback_machine.register_key_input_callback(move(keys), move(callback)); }
     void register_key_input_callback(Key key, Function<bool(Editor&)> callback) { register_key_input_callback(Vector<Key> { key }, move(callback)); }
 
-    static StringMetrics actual_rendered_string_metrics(StringView);
-    static StringMetrics actual_rendered_string_metrics(Utf32View const&);
+    static StringMetrics actual_rendered_string_metrics(StringView, RedBlackTree<u32, Optional<Style::Mask>> const& masks = {});
+    static StringMetrics actual_rendered_string_metrics(Utf32View const&, RedBlackTree<u32, Optional<Style::Mask>> const& masks = {});
 
     Function<Vector<CompletionSuggestion>(Editor const&)> on_tab_complete;
     Function<void(Utf32View, Editor&)> on_paste;
@@ -202,7 +203,7 @@ public:
         if (m_cached_prompt_valid)
             m_old_prompt_metrics = m_cached_prompt_metrics;
         m_cached_prompt_valid = false;
-        m_cached_prompt_metrics = actual_rendered_string_metrics(prompt);
+        m_cached_prompt_metrics = actual_rendered_string_metrics(prompt, {});
         m_new_prompt = prompt;
     }
 
@@ -260,16 +261,6 @@ private:
 
     void set_default_keybinds();
 
-    enum VTState {
-        Free = 1,
-        Escape = 3,
-        Bracket = 5,
-        BracketArgsSemi = 7,
-        Title = 9,
-    };
-
-    static VTState actual_rendered_string_length_step(StringMetrics&, size_t, StringMetrics::LineMetrics& current_line, u32, u32, VTState);
-
     enum LoopExitCode {
         Exit = 0,
         Retry
@@ -366,7 +357,7 @@ private:
         if (cursor > m_cursor)
             cursor = m_cursor;
         return current_prompt_metrics().lines_with_addition(
-            actual_rendered_string_metrics(buffer_view().substring_view(0, cursor)),
+            actual_rendered_string_metrics(buffer_view().substring_view(0, cursor), m_current_masks),
             m_num_columns);
     }
 
@@ -375,7 +366,7 @@ private:
         auto cursor = m_drawn_cursor;
         if (cursor > m_cursor)
             cursor = m_cursor;
-        auto buffer_metrics = actual_rendered_string_metrics(buffer_view().substring_view(0, cursor));
+        auto buffer_metrics = actual_rendered_string_metrics(buffer_view().substring_view(0, cursor), m_current_masks);
         return current_prompt_metrics().offset_with_addition(buffer_metrics, m_num_columns);
     }
 
@@ -508,6 +499,8 @@ private:
         bool contains_up_to_offset(Spans const& other, size_t offset) const;
     } m_drawn_spans, m_current_spans;
 
+    RedBlackTree<u32, Optional<Style::Mask>> m_current_masks;
+
     RefPtr<Core::Notifier> m_notifier;
 
     Vector<u32> m_paste_buffer;

Userland/Libraries/LibLine/InternalFunctions.cpp

@@ -345,8 +345,8 @@ void Editor::enter_search()
         // Manually cleanup the search line.
         OutputFileStream stderr_stream { stderr };
         reposition_cursor(stderr_stream);
-        auto search_metrics = actual_rendered_string_metrics(search_string);
-        auto metrics = actual_rendered_string_metrics(search_prompt);
+        auto search_metrics = actual_rendered_string_metrics(search_string, {});
+        auto metrics = actual_rendered_string_metrics(search_prompt, {});
         VT::clear_lines(0, metrics.lines_with_addition(search_metrics, m_num_columns) + search_end_row - m_origin_row - 1, stderr_stream);
 
         reposition_cursor(stderr_stream);

Userland/Libraries/LibLine/StringMetrics.h

@@ -21,17 +21,7 @@ struct StringMetrics {
         Vector<MaskedChar> masked_chars;
         size_t length { 0 };
 
-        size_t total_length(ssize_t offset = -1) const
-        {
-            size_t length = this->length;
-            for (auto& mask : masked_chars) {
-                if (offset < 0 || mask.position <= (size_t)offset) {
-                    length -= mask.original_length;
-                    length += mask.masked_length;
-                }
-            }
-            return length;
-        }
+        size_t total_length() const { return length; }
     };
 
     Vector<LineMetrics> line_metrics;

Userland/Libraries/LibLine/Style.h

@@ -106,6 +106,28 @@ public:
         bool m_has_link { false };
     };
 
+    struct Mask {
+        bool operator==(Mask const& other) const
+        {
+            return other.mode == mode && other.replacement == replacement;
+        }
+
+        enum class Mode {
+            ReplaceEntireSelection,
+            ReplaceEachCodePointInSelection,
+        };
+        explicit Mask(StringView replacement, Mode mode = Mode::ReplaceEntireSelection)
+            : replacement(replacement)
+            , replacement_view(this->replacement)
+            , mode(mode)
+        {
+        }
+
+        String replacement;
+        mutable Utf8View replacement_view;
+        Mode mode;
+    };
+
     static constexpr UnderlineTag Underline {};
     static constexpr BoldTag Bold {};
     static constexpr ItalicTag Italic {};
@@ -141,6 +163,9 @@ public:
     Background background() const { return m_background; }
     Foreground foreground() const { return m_foreground; }
     Hyperlink hyperlink() const { return m_hyperlink; }
+    Optional<Mask> mask() const { return m_mask; }
+
+    void unset_mask() const { m_mask = {}; }
 
     void set(ItalicTag const&) { m_italic = true; }
     void set(BoldTag const&) { m_bold = true; }
@@ -149,6 +174,7 @@ public:
     void set(Foreground const& fg) { m_foreground = fg; }
     void set(Hyperlink const& link) { m_hyperlink = link; }
     void set(AnchoredTag const&) { m_is_anchored = true; }
+    void set(Mask const& mask) { m_mask = mask; }
 
     bool is_anchored() const { return m_is_anchored; }
     bool is_empty() const { return m_is_empty; }
@@ -162,6 +188,7 @@ private:
     Background m_background { XtermColor::Unchanged };
     Foreground m_foreground { XtermColor::Unchanged };
     Hyperlink m_hyperlink;
+    mutable Optional<Mask> m_mask;
 
     bool m_is_anchored { false };