From 7ef48171ce1585d91dbd37568b8fefcd1443245e Mon Sep 17 00:00:00 2001 From: AnotherTest Date: Sun, 19 Apr 2020 15:55:17 +0430 Subject: [PATCH] LibLine: Complete only common prefixes, and tweak suggestion logic On the first tab, only complete the token without suggesting extra stuff, and on further tabs, show suggestions. Except in one case where the completion is all in the buffer, then we show the suggestions, but do no completion. --- Libraries/LibLine/Editor.cpp | 97 +++++++++++++++++++++++++++++++----- Libraries/LibLine/Editor.h | 5 +- 2 files changed, 88 insertions(+), 14 deletions(-) diff --git a/Libraries/LibLine/Editor.cpp b/Libraries/LibLine/Editor.cpp index 71e5f0a79d7..3958bec31d6 100644 --- a/Libraries/LibLine/Editor.cpp +++ b/Libraries/LibLine/Editor.cpp @@ -290,12 +290,38 @@ String Editor::get_line(const String& prompt) String token = is_empty_token ? String() : String(&m_buffer[token_start], m_cursor - token_start); // ask for completions only on the first tab + // and scan for the largest common prefix to display // further tabs simply show the cached completions if (m_times_tab_pressed == 1) { if (is_first_token) m_suggestions = on_tab_complete_first_token(token); else m_suggestions = on_tab_complete_other_token(token); + size_t common_suggestion_prefix { 0 }; + if (m_suggestions.size() == 1) { + m_largest_common_suggestion_prefix_length = m_suggestions[0].length(); + } else if (m_suggestions.size()) { + char last_valid_suggestion_char; + for (;; ++common_suggestion_prefix) { + if (m_suggestions[0].length() <= common_suggestion_prefix) + goto no_more_commons; + + last_valid_suggestion_char = m_suggestions[0][common_suggestion_prefix]; + + for (const auto& suggestion : m_suggestions) { + if (suggestion.length() < common_suggestion_prefix || suggestion[common_suggestion_prefix] != last_valid_suggestion_char) { + goto no_more_commons; + } + } + } + no_more_commons:; + m_largest_common_suggestion_prefix_length = common_suggestion_prefix; + } else { + m_largest_common_suggestion_prefix_length = 0; + // there are no suggestions, beep~ + putchar('\a'); + fflush(stdout); + } m_prompt_lines_at_suggestion_initiation = num_lines(); } @@ -314,19 +340,57 @@ String Editor::get_line(const String& prompt) auto current_suggestion_index = m_next_suggestion_index; if (m_next_suggestion_index < m_suggestions.size()) { + auto can_complete = m_next_suggestion_invariant_offset < m_largest_common_suggestion_prefix_length; if (!m_last_shown_suggestion.is_null()) { - auto actual_offset = m_times_tab_pressed == 1 ? m_cursor : m_cursor - m_last_shown_suggestion.length() + m_next_suggestion_invariant_offset; - for (size_t i = m_next_suggestion_invariant_offset; i < m_last_shown_suggestion.length(); ++i) + size_t actual_offset; + size_t shown_length = m_last_shown_suggestion_display_length; + switch (m_times_tab_pressed) { + case 1: + actual_offset = m_cursor; + break; + case 2: + actual_offset = m_cursor - m_largest_common_suggestion_prefix_length + m_next_suggestion_invariant_offset; + if (can_complete) + shown_length = m_largest_common_suggestion_prefix_length; + break; + default: + if (m_last_shown_suggestion_display_length == 0) + actual_offset = m_cursor; + else + actual_offset = m_cursor - m_last_shown_suggestion_display_length + m_next_suggestion_invariant_offset; + break; + } + + for (size_t i = m_next_suggestion_invariant_offset; i < shown_length; ++i) m_buffer.remove(actual_offset); m_cursor = actual_offset; m_refresh_needed = true; } m_last_shown_suggestion = m_suggestions[m_next_suggestion_index]; - insert(m_last_shown_suggestion.substring_view(m_next_suggestion_invariant_offset, m_last_shown_suggestion.length() - m_next_suggestion_invariant_offset)); - if (m_tab_direction == TabDirection::Forward) - increment_suggestion_index(); - else - decrement_suggestion_index(); + m_last_shown_suggestion_display_length = m_last_shown_suggestion.length(); + m_last_shown_suggestion_was_complete = true; + if (m_times_tab_pressed == 1) { + // This is the first time, so only auto-complete *if possible* + if (can_complete) { + insert(m_last_shown_suggestion.substring_view(m_next_suggestion_invariant_offset, m_largest_common_suggestion_prefix_length - m_next_suggestion_invariant_offset)); + m_last_shown_suggestion_display_length = m_largest_common_suggestion_prefix_length; + // do not increment the suggestion index, as the first tab should only be a *peek* + if (m_suggestions.size() == 1) { + // if there's one suggestion, commit and forget + m_times_tab_pressed = 0; + } + } else { + m_last_shown_suggestion_display_length = 0; + } + ++m_times_tab_pressed; + m_last_shown_suggestion_was_complete = false; + } else { + insert(m_last_shown_suggestion.substring_view(m_next_suggestion_invariant_offset, m_last_shown_suggestion.length() - m_next_suggestion_invariant_offset)); + if (m_tab_direction == TabDirection::Forward) + increment_suggestion_index(); + else + decrement_suggestion_index(); + } } else { m_next_suggestion_index = 0; } @@ -373,7 +437,8 @@ String Editor::get_line(const String& prompt) if (lines_used + m_prompt_lines_at_suggestion_initiation >= m_num_lines) break; - if (index == current_suggestion_index) { + // only apply colour to the selection if something is *actually* added to the buffer + if (m_last_shown_suggestion_was_complete && index == current_suggestion_index) { vt_apply_style({ Style::Foreground(Style::Color::Blue) }); fflush(stdout); } @@ -385,7 +450,7 @@ String Editor::get_line(const String& prompt) num_printed += fprintf(stderr, "%-*s", static_cast(longest_suggestion_length) + 2, suggestion.characters()); } - if (index == current_suggestion_index) { + if (m_last_shown_suggestion_was_complete && index == current_suggestion_index) { vt_apply_style({}); fflush(stdout); } @@ -405,6 +470,7 @@ String Editor::get_line(const String& prompt) // after it, as if it were auto-completed suggest(0, 0); m_last_shown_suggestion = String::empty(); + m_last_shown_suggestion_display_length = 0; m_suggestions.clear(); m_times_tab_pressed = 0; } @@ -420,6 +486,7 @@ String Editor::get_line(const String& prompt) m_refresh_needed = true; m_lines_used_for_last_suggestions = 0; } + m_last_shown_suggestion_display_length = 0; m_last_shown_suggestion = String::empty(); m_suggestions.clear(); suggest(0, 0); @@ -462,7 +529,8 @@ String Editor::get_line(const String& prompt) m_refresh_needed = true; continue; } - if (ch == 0xc) { // ^L + // ^L + if (ch == 0xc) { printf("\033[3J\033[H\033[2J"); // Clear screen. vt_move_absolute(1, 1); m_origin_x = 1; @@ -470,18 +538,21 @@ String Editor::get_line(const String& prompt) m_refresh_needed = true; continue; } - if (ch == 0x01) { // ^A + // ^A + if (ch == 0x01) { m_cursor = 0; continue; } - if (ch == m_termios.c_cc[VEOF]) { // Normally ^D + // Normally ^D + if (ch == m_termios.c_cc[VEOF]) { if (m_buffer.is_empty()) { printf("\n"); exit(0); } continue; } - if (ch == 0x05) { // ^E + // ^E + if (ch == 0x05) { m_cursor = m_buffer.size(); continue; diff --git a/Libraries/LibLine/Editor.h b/Libraries/LibLine/Editor.h index 618e0f38f8f..f5085cfcbd0 100644 --- a/Libraries/LibLine/Editor.h +++ b/Libraries/LibLine/Editor.h @@ -196,9 +196,12 @@ private: String m_new_prompt; Vector m_suggestions; - String m_last_shown_suggestion; + String m_last_shown_suggestion { String::empty() }; + size_t m_last_shown_suggestion_display_length { 0 }; + bool m_last_shown_suggestion_was_complete { false }; size_t m_next_suggestion_index { 0 }; size_t m_next_suggestion_invariant_offset { 0 }; + size_t m_largest_common_suggestion_prefix_length { 0 }; enum class TabDirection { Forward,