path: root/src/nvim/terminal.c

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// VT220/xterm-like terminal emulator.
// Powered by libvterm http://www.leonerd.org.uk/code/libvterm
//
// libvterm is a pure C99 terminal emulation library with abstract input and
// display. This means that the library needs to read data from the master fd
// and feed VTerm instances, which will invoke user callbacks with screen
// update instructions that must be mirrored to the real display.
//
// Keys are sent to VTerm instances by calling
// vterm_keyboard_key/vterm_keyboard_unichar, which generates byte streams that
// must be fed back to the master fd.
//
// Nvim buffers are used as the display mechanism for both the visible screen
// and the scrollback buffer.
//
// When a line becomes invisible due to a decrease in screen height or because
// a line was pushed up during normal terminal output, we store the line
// information in the scrollback buffer, which is mirrored in the nvim buffer
// by appending lines just above the visible part of the buffer.
//
// When the screen height increases, libvterm will ask for a row in the
// scrollback buffer, which is mirrored in the nvim buffer displaying lines
// that were previously invisible.
//
// The vterm->nvim synchronization is performed in intervals of 10 milliseconds,
// to minimize screen updates when receiving large bursts of data.
//
// This module is decoupled from the processes that normally feed it data, so
// it's possible to use it as a general purpose console buffer (possibly as a
// log/display mechanism for nvim in the future)
//
// Inspired by: vimshell http://www.wana.at/vimshell
//              Conque https://code.google.com/p/conque
// Some code from pangoterm http://www.leonerd.org.uk/code/pangoterm

#include <assert.h>
#include <stdio.h>
#include <stdint.h>
#include <stdbool.h>

#include <vterm.h>

#include "nvim/log.h"
#include "nvim/vim.h"
#include "nvim/terminal.h"
#include "nvim/message.h"
#include "nvim/memory.h"
#include "nvim/option.h"
#include "nvim/highlight.h"
#include "nvim/macros.h"
#include "nvim/mbyte.h"
#include "nvim/buffer.h"
#include "nvim/change.h"
#include "nvim/ascii.h"
#include "nvim/getchar.h"
#include "nvim/ui.h"
#include "nvim/syntax.h"
#include "nvim/screen.h"
#include "nvim/keymap.h"
#include "nvim/edit.h"
#include "nvim/mouse.h"
#include "nvim/memline.h"
#include "nvim/map.h"
#include "nvim/misc1.h"
#include "nvim/move.h"
#include "nvim/main.h"
#include "nvim/state.h"
#include "nvim/ex_docmd.h"
#include "nvim/ex_cmds.h"
#include "nvim/window.h"
#include "nvim/fileio.h"
#include "nvim/event/loop.h"
#include "nvim/event/time.h"
#include "nvim/os/input.h"
#include "nvim/api/private/helpers.h"

typedef struct terminal_state {
  VimState state;
  Terminal *term;
  int save_rd;              // saved value of RedrawingDisabled
  bool close;
  bool got_bsl;             // if the last input was <C-\>
} TerminalState;

#ifdef INCLUDE_GENERATED_DECLARATIONS
# include "terminal.c.generated.h"
#endif

// Delay for refreshing the terminal buffer after receiving updates from
// libvterm. Improves performance when receiving large bursts of data.
#define REFRESH_DELAY 10

static TimeWatcher refresh_timer;
static bool refresh_pending = false;

typedef struct {
  size_t cols;
  VTermScreenCell cells[];
} ScrollbackLine;

struct terminal {
  TerminalOptions opts;  // options passed to terminal_open
  VTerm *vt;
  VTermScreen *vts;
  // buffer used to:
  //  - convert VTermScreen cell arrays into utf8 strings
  //  - receive data from libvterm as a result of key presses.
  char textbuf[0x1fff];

  ScrollbackLine **sb_buffer;       // Scrollback buffer storage for libvterm
  size_t sb_current;                // number of rows pushed to sb_buffer
  size_t sb_size;                   // sb_buffer size
  // "virtual index" that points to the first sb_buffer row that we need to
  // push to the terminal buffer when refreshing the scrollback. When negative,
  // it actually points to entries that are no longer in sb_buffer (because the
  // window height has increased) and must be deleted from the terminal buffer
  int sb_pending;

  // buf_T instance that acts as a "drawing surface" for libvterm
  // we can't store a direct reference to the buffer because the
  // refresh_timer_cb may be called after the buffer was freed, and there's
  // no way to know if the memory was reused.
  handle_T buf_handle;
  // program exited
  bool closed, destroy;