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https://github.com/RGBCube/serenity
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The Alternate Screen Buffer is used by full-screen terminal applications (like `vim` and `nano`). Its data is stored separately from the normal buffer, therefore after applications using it exit, everything looks like it was before, the bottom of their interfaces isn't visible. An interesting feature is that it does not support scrollback, so it consumes less memory by not having to allocate lines for history. Because of the need to save and restore state between the switches, some correctness issues relating to it were also fixed in this commit.
401 lines
10 KiB
C++
401 lines
10 KiB
C++
/*
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* Copyright (c) 2018-2020, Andreas Kling <kling@serenityos.org>
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* Copyright (c) 2021, Daniel Bertalan <dani@danielbertalan.dev>
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*
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* SPDX-License-Identifier: BSD-2-Clause
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*/
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#pragma once
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#include <AK/Noncopyable.h>
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#include <AK/NonnullOwnPtrVector.h>
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#include <AK/String.h>
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#include <AK/Vector.h>
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#include <Kernel/API/KeyCode.h>
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#include <LibVT/EscapeSequenceParser.h>
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#include <LibVT/Position.h>
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#ifndef KERNEL
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# include <LibVT/Attribute.h>
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# include <LibVT/Line.h>
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#else
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namespace Kernel {
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class VirtualConsole;
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}
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# include <LibVT/Attribute.h>
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#endif
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namespace VT {
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enum CursorStyle {
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None,
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BlinkingBlock,
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SteadyBlock,
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BlinkingUnderline,
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SteadyUnderline,
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BlinkingBar,
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SteadyBar
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};
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class TerminalClient {
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public:
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virtual ~TerminalClient() { }
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virtual void beep() = 0;
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virtual void set_window_title(const StringView&) = 0;
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virtual void set_window_progress(int value, int max) = 0;
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virtual void terminal_did_resize(u16 columns, u16 rows) = 0;
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virtual void terminal_history_changed() = 0;
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virtual void emit(const u8*, size_t) = 0;
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virtual void set_cursor_style(CursorStyle) = 0;
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};
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class Terminal : public EscapeSequenceExecutor {
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public:
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#ifndef KERNEL
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explicit Terminal(TerminalClient&);
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#else
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explicit Terminal(Kernel::VirtualConsole&);
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#endif
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virtual ~Terminal()
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{
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}
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bool m_need_full_flush { false };
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#ifndef KERNEL
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void invalidate_cursor();
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#else
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virtual void invalidate_cursor() = 0;
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#endif
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void on_input(u8);
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void set_cursor(unsigned row, unsigned column, bool skip_debug = false);
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#ifndef KERNEL
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void clear();
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void clear_including_history();
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#else
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virtual void clear() = 0;
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virtual void clear_including_history() = 0;
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#endif
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#ifndef KERNEL
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void set_size(u16 columns, u16 rows);
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#else
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virtual void set_size(u16 columns, u16 rows) = 0;
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#endif
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u16 columns() const
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{
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return m_columns;
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}
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u16 rows() const { return m_rows; }
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u16 cursor_column() const { return m_current_state.cursor.column; }
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u16 cursor_row() const { return m_current_state.cursor.row; }
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#ifndef KERNEL
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size_t line_count() const
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{
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if (m_use_alternate_screen_buffer)
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return m_alternate_screen_buffer.size();
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else
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return m_history.size() + m_normal_screen_buffer.size();
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}
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Line& line(size_t index)
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{
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if (m_use_alternate_screen_buffer) {
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return m_alternate_screen_buffer[index];
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} else {
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if (index < m_history.size())
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return m_history[(m_history_start + index) % m_history.size()];
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return m_normal_screen_buffer[index - m_history.size()];
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}
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}
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const Line& line(size_t index) const
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{
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return const_cast<Terminal*>(this)->line(index);
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}
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Line& visible_line(size_t index)
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{
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return active_buffer()[index];
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}
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const Line& visible_line(size_t index) const
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{
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return active_buffer()[index];
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}
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size_t max_history_size() const { return m_max_history_lines; }
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void set_max_history_size(size_t value)
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{
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if (value == 0) {
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m_max_history_lines = 0;
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m_history_start = 0;
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m_history.clear();
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m_client.terminal_history_changed();
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return;
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}
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if (m_max_history_lines > value) {
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NonnullOwnPtrVector<Line> new_history;
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new_history.ensure_capacity(value);
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auto existing_line_count = min(m_history.size(), value);
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for (size_t i = m_history.size() - existing_line_count; i < m_history.size(); ++i) {
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auto j = (m_history_start + i) % m_history.size();
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new_history.unchecked_append(move(static_cast<Vector<NonnullOwnPtr<Line>>&>(m_history).at(j)));
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}
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m_history = move(new_history);
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m_history_start = 0;
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m_client.terminal_history_changed();
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}
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m_max_history_lines = value;
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}
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size_t history_size() const { return m_history.size(); }
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#endif
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void inject_string(const StringView&);
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void handle_key_press(KeyCode, u32, u8 flags);
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#ifndef KERNEL
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Attribute attribute_at(const Position&) const;
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#endif
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bool needs_bracketed_paste() const
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{
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return m_needs_bracketed_paste;
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};
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protected:
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// ^EscapeSequenceExecutor
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virtual void emit_code_point(u32) override;
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virtual void execute_control_code(u8) override;
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virtual void execute_escape_sequence(Intermediates intermediates, bool ignore, u8 last_byte) override;
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virtual void execute_csi_sequence(Parameters parameters, Intermediates intermediates, bool ignore, u8 last_byte) override;
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virtual void execute_osc_sequence(OscParameters parameters, u8 last_byte) override;
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virtual void dcs_hook(Parameters parameters, Intermediates intermediates, bool ignore, u8 last_byte) override;
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virtual void receive_dcs_char(u8 byte) override;
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virtual void execute_dcs_sequence() override;
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struct CursorPosition {
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u16 row { 0 };
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u16 column { 0 };
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void clamp(u16 max_row, u16 max_column)
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{
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row = min(row, max_row);
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column = min(column, max_column);
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}
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};
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struct BufferState {
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Attribute attribute;
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CursorPosition cursor;
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};
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void carriage_return();
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#ifndef KERNEL
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void scroll_up();
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void scroll_down();
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void linefeed();
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void put_character_at(unsigned row, unsigned column, u32 ch);
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void set_window_title(const String&);
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#else
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virtual void scroll_up() = 0;
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virtual void scroll_down() = 0;
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virtual void linefeed() = 0;
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virtual void put_character_at(unsigned row, unsigned column, u32 ch) = 0;
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virtual void set_window_title(const String&) = 0;
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#endif
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void unimplemented_control_code(u8);
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void unimplemented_escape_sequence(Intermediates, u8 last_byte);
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void unimplemented_csi_sequence(Parameters, Intermediates, u8 last_byte);
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void unimplemented_osc_sequence(OscParameters, u8 last_byte);
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void emit_string(const StringView&);
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void alter_mode(bool should_set, Parameters, Intermediates);
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// CUU – Cursor Up
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void CUU(Parameters);
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// CUD – Cursor Down
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void CUD(Parameters);
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// CUF – Cursor Forward
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void CUF(Parameters);
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// CUB – Cursor Backward
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void CUB(Parameters);
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// CUP - Cursor Position
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void CUP(Parameters);
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// ED - Erase in Display
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void ED(Parameters);
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// EL - Erase in Line
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void EL(Parameters);
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// SGR – Select Graphic Rendition
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void SGR(Parameters);
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// Save Current Cursor Position
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void SCOSC();
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// Restore Saved Cursor Position
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void SCORC();
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// Save Cursor (and other attributes)
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void DECSC();
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// Restore Cursor (and other attributes)
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void DECRC();
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// DECSTBM – Set Top and Bottom Margins ("Scrolling Region")
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void DECSTBM(Parameters);
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// RM – Reset Mode
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void RM(Parameters, Intermediates);
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// SM – Set Mode
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void SM(Parameters, Intermediates);
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// DA - Device Attributes
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void DA(Parameters);
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// HVP – Horizontal and Vertical Position
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void HVP(Parameters);
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// NEL - Next Line
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void NEL();
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// IND - Index (move down)
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void IND();
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// RI - Reverse Index (move up)
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void RI();
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// DSR - Device Status Reports
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void DSR(Parameters);
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// DECSCUSR - Set Cursor Style
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void DECSCUSR(Parameters);
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#ifndef KERNEL
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// ICH - Insert Character
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void ICH(Parameters);
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#else
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virtual void ICH(Parameters) = 0;
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#endif
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// SU - Scroll Up (called "Pan Down" in VT510)
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void SU(Parameters);
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// SD - Scroll Down (called "Pan Up" in VT510)
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void SD(Parameters);
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#ifndef KERNEL
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// IL - Insert Line
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void IL(Parameters);
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// DCH - Delete Character
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void DCH(Parameters);
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// DL - Delete Line
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void DL(Parameters);
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#else
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virtual void IL(Parameters) = 0;
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virtual void DCH(Parameters) = 0;
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virtual void DL(Parameters) = 0;
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#endif
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// CHA - Cursor Horizontal Absolute
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void CHA(Parameters);
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// REP - Repeat
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void REP(Parameters);
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// VPA - Vertical Line Position Absolute
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void VPA(Parameters);
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// ECH - Erase Character
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void ECH(Parameters);
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// FIXME: Find the right names for these.
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void XTERM_WM(Parameters);
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#ifndef KERNEL
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TerminalClient& m_client;
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#else
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Kernel::VirtualConsole& m_client;
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#endif
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EscapeSequenceParser m_parser;
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#ifndef KERNEL
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size_t m_history_start = 0;
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NonnullOwnPtrVector<Line> m_history;
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void add_line_to_history(NonnullOwnPtr<Line>&& line)
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{
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if (max_history_size() == 0)
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return;
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if (m_history.size() < max_history_size()) {
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VERIFY(m_history_start == 0);
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m_history.append(move(line));
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return;
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}
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m_history.ptr_at(m_history_start) = move(line);
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m_history_start = (m_history_start + 1) % m_history.size();
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}
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NonnullOwnPtrVector<Line>& active_buffer() { return m_use_alternate_screen_buffer ? m_alternate_screen_buffer : m_normal_screen_buffer; };
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const NonnullOwnPtrVector<Line>& active_buffer() const { return m_use_alternate_screen_buffer ? m_alternate_screen_buffer : m_normal_screen_buffer; };
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NonnullOwnPtrVector<Line> m_normal_screen_buffer;
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NonnullOwnPtrVector<Line> m_alternate_screen_buffer;
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#endif
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bool m_use_alternate_screen_buffer { false };
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size_t m_scroll_region_top { 0 };
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size_t m_scroll_region_bottom { 0 };
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u16 m_columns { 1 };
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u16 m_rows { 1 };
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BufferState m_current_state;
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BufferState m_normal_saved_state;
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BufferState m_alternate_saved_state;
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// Separate from *_saved_state: some escape sequences only save/restore the cursor position,
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// while others impact the text attributes and other state too.
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CursorPosition m_saved_cursor_position;
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bool m_swallow_current { false };
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bool m_stomp { false };
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CursorStyle m_cursor_style { BlinkingBlock };
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CursorStyle m_saved_cursor_style { BlinkingBlock };
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bool m_needs_bracketed_paste { false };
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Attribute m_current_attribute;
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Attribute m_saved_attribute;
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String m_current_window_title;
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Vector<String> m_title_stack;
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#ifndef KERNEL
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u32 m_next_href_id { 0 };
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#endif
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Vector<bool> m_horizontal_tabs;
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u32 m_last_code_point { 0 };
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size_t m_max_history_lines { 1024 };
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};
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}
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