// High level library for handling the terminal screen.
//
// The screen library allows the interactive reader to write its output to screen efficiently by
// keeping an internal representation of the current screen contents and trying to find the most
// efficient way for transforming that to the desired screen content.
//
// IWYU pragma: no_include <cstddef>
#include "config.h"
#include <stddef.h>
#include <stdio.h>
#include <stdlib.h>
#include <termios.h>
#include <time.h>
#include <unistd.h>
#include <cstring>
#include <cwchar>
#if HAVE_CURSES_H
#include <curses.h>
#elif HAVE_NCURSES_H
#include <ncurses.h>
#elif HAVE_NCURSES_CURSES_H
#include <ncurses/curses.h>
#endif
#if HAVE_TERM_H
#include <term.h>
#elif HAVE_NCURSES_TERM_H
#include <ncurses/term.h>
#endif
#include <algorithm>
#include <string>
#include <vector>
#include "common.h"
#include "env.h"
#include "fallback.h" // IWYU pragma: keep
#include "flog.h"
#include "highlight.h"
#include "output.h"
#include "pager.h"
#include "screen.h"
/// The number of characters to indent new blocks.
#define INDENT_STEP 4u
static void invalidate_soft_wrap(screen_t *scr);
/// RAII class to begin and end buffering around stdoutput().
class scoped_buffer_t {
screen_t &screen_;
public:
explicit scoped_buffer_t(screen_t &s) : screen_(s) { screen_.outp().begin_buffering(); }
~scoped_buffer_t() { screen_.outp().end_buffering(); }
};
// Singleton of the cached escape sequences seen in prompts and similar strings.
// Note this is deliberately exported so that init_curses can clear it.
layout_cache_t layout_cache_t::shared;
/// Tests if the specified narrow character sequence is present at the specified position of the
/// specified wide character string. All of \c seq must match, but str may be longer than seq.
static size_t try_sequence(const char *seq, const wchar_t *str) {
for (size_t i = 0;; i++) {
if (!seq[i]) return i;
if (seq[i] != str[i]) return 0;
}
DIE("unexpectedly fell off end of try_sequence()");
return 0; // this should never be executed
}
/// Returns the number of columns left until the next tab stop, given the current cursor position.
static size_t next_tab_stop(size_t current_line_width) {
// Assume tab stops every 8 characters if undefined.
size_t tab_width = init_tabs > 0 ? static_cast<size_t>(init_tabs) : 8;
return ((current_line_width / tab_width) + 1) * tab_width;
}
/// Like fish_wcwidth, but returns 0 for control characters instead of -1.
static int fish_wcwidth_min_0(wchar_t widechar) { return std::max(0, fish_wcwidth(widechar)); }
int line_t::wcswidth_min_0(size_t max) const {
int result = 0;
for (size_t idx = 0, end = std::min(max, text.size()); idx < end; idx++) {
result += fish_wcwidth_min_0(text[idx].character);
}
return result;
}
/// Whether we permit soft wrapping. If so, in some cases we don't explicitly move to the second
/// physical line on a wrapped logical line; instead we just output it.
static bool allow_soft_wrap() {
// Should we be looking at eat_newline_glitch as well?
return auto_right_margin;
}
/// Does this look like the escape sequence for setting a screen name?
static bool is_screen_name_escape_seq(const wchar_t *code, size_t *resulting_length) {
if (code[1] != L'k') {
return false;
}
const wchar_t *const screen_name_end_sentinel = L"\x1B\\";
const wchar_t *screen_name_end = std::wcsstr(&code[2], screen_name_end_sentinel);
if (screen_name_end == nullptr) {
// Consider just <esc>k to be the code.
*resulting_length = 2;
} else {
const wchar_t *escape_sequence_end =
screen_name_end + std::wcslen(screen_name_end_sentinel);
*resulting_length = escape_sequence_end - code;
}
return true;
}
/// Operating System Command (OSC) escape codes, used by iTerm2 and others:
/// ESC followed by ], terminated by either BEL or escape + backslash.
/// See https://invisible-island.net/xterm/ctlseqs/ctlseqs.html
/// and https://iterm2.com/documentation-escape-codes.html .
static bool is_osc_escape_seq(const wchar_t *code, size_t *resulting_length) {
bool found = false;
if (code[1] == ']') {
// Start at 2 to skip over <esc>].
size_t cursor = 2;
for (; code[cursor] != L'\0'; cursor++) {
// Consume a sequence of characters up to <esc>\ or <bel>.
if (code[cursor] == '\x07' || (code[cursor] == '\\' && code[cursor - 1] == '\x1B')) {
found = true;
break;
}
}
if (found) {
*resulting_length = cursor + 1;
}
}
return found;
}
/// Generic VT100 three byte sequence: CSI followed by something in the range @ through _.
static bool is_three_byte_escape_seq(const wchar_t *code, size_t *resulting_length) {
bool found = false;
if (code[1] == L'[' && (code[2] >= L'@' && code[2] <= L'_')) {
*resulting_length = 3;
found = true;
}
return found;
}
/// Generic VT100 two byte sequence: <esc> followed by something in the range @ through _.
static bool is_two_byte_escape_seq(const wchar_t *code, size_t *resulting_length) {
bool found = false;
if (code[1] >= L'@' && code[1] <= L'_') {
*resulting_length = 2;
found = true;
}
return found;
}
/// Generic VT100 CSI-style sequence. <esc>, followed by zero or more ASCII characters NOT in
/// the range [@,_], followed by one character in that range.
static bool is_csi_style_escape_seq(const wchar_t *code, size_t *resulting_length) {
if (code[1] != L'[') {
return false;
}
// Start at 2 to skip over <esc>[
size_t cursor = 2;
for (; code[cursor] != L'\0'; cursor++) {
// Consume a sequence of ASCII characters not in the range [@, ~].
wchar_t widechar = code[cursor];
// If we're not in ASCII, just stop.
if (widechar > 127) break;
// If we're the end character, then consume it and then stop.
if (widechar >= L'@' && widechar <= L'~') {
cursor++;
break;
}
}
// cursor now indexes just beyond the end of the sequence (or at the terminating zero).
*resulting_length = cursor;
return true;
}
/// Detect whether the escape sequence sets foreground/background color. Note that 24-bit color
/// sequences are detected by `is_csi_style_escape_seq()` if they use the ANSI X3.64 pattern for
/// such sequences. This function only handles those escape sequences for setting color that rely on
/// the terminfo definition and which might use a different pattern.
static bool is_color_escape_seq(const wchar_t *code, size_t *resulting_length) {
if (!cur_term) return false;
// Detect these terminfo color escapes with parameter value up to max_colors, all of which
// don't move the cursor.
const char *const esc[] = {
set_a_foreground,
set_a_background,
set_foreground,
set_background,
};
for (auto p : esc) {
if (!p) continue;
for (int k = 0; k < max_colors; k++) {
size_t esc_seq_len = try_sequence(tparm(const_cast<char *>(p), k), code);
if (esc_seq_len) {
*resulting_length = esc_seq_len;
return true;
}
}
}
return false;
}
/// Detect whether the escape sequence sets one of the terminal attributes that affects how text is
/// displayed other than the color.
static bool is_visual_escape_seq(const wchar_t *code, size_t *resulting_length) {
if (!cur_term) return false;
const char *const esc2[] = {
enter_bold_mode, exit_attribute_mode, enter_underline_mode, exit_underline_mode,
enter_standout_mode, exit_standout_mode, enter_blink_mode, enter_protected_mode,
enter_italics_mode, exit_italics_mode, enter_reverse_mode, enter_shadow_mode,
exit_shadow_mode, enter_standout_mode, exit_standout_mode, enter_secure_mode,
enter_dim_mode, enter_blink_mode, enter_alt_charset_mode, exit_alt_charset_mode};
for (auto p : esc2) {
if (!p) continue;
// Test both padded and unpadded version, just to be safe. Most versions of tparm don't
// actually seem to do anything these days.
size_t esc_seq_len =
std::max(try_sequence(tparm(const_cast<char *>(p)), code), try_sequence(p, code));
if (esc_seq_len) {
*resulting_length = esc_seq_len;
return true;
}
}
return false;
}
/// Returns the number of characters in the escape code starting at 'code'. We only handle sequences
/// that begin with \x1B. If it doesn't we return zero. We also return zero if we don't recognize
/// the escape sequence based on querying terminfo and other heuristics.
size_t layout_cache_t::escape_code_length(const wchar_t *code) {
assert(code != nullptr);
if (*code != L'\x1B') return 0;
size_t esc_seq_len = this->find_escape_code(code);
if (esc_seq_len) return esc_seq_len;
bool found = is_color_escape_seq(code, &esc_seq_len);
if (!found) found = is_visual_escape_seq(code, &esc_seq_len);
if (!found) found = is_screen_name_escape_seq(code, &esc_seq_len);
if (!found) found = is_osc_escape_seq(code, &esc_seq_len);
if (!found) found = is_three_byte_escape_seq(code, &esc_seq_len);
if (!found) found = is_csi_style_escape_seq(code, &esc_seq_len);
if (!found) found = is_two_byte_escape_seq(code, &esc_seq_len);
if (found) this->add_escape_code(wcstring(code, esc_seq_len));
return esc_seq_len;
}
const layout_cache_t::prompt_cache_entry_t *layout_cache_t::find_prompt_layout(
const wcstring &input, size_t max_line_width) {
auto start = prompt_cache_.begin();
auto end = prompt_cache_.end();
for (auto iter = start; iter != end; ++iter) {
if (iter->text == input && iter->max_line_width == max_line_width) {
// Found it. Move it to the front if not already there.
if (iter != start) prompt_cache_.splice(start, prompt_cache_, iter);
return &*prompt_cache_.begin();
}
}
return nullptr;
}
void layout_cache_t::add_prompt_layout(prompt_cache_entry_t entry) {
prompt_cache_.emplace_front(std::move(entry));
if (prompt_cache_.size() > prompt_cache_max_size) {
prompt_cache_.pop_back();
}
}
/// \return whether \p c ends a measuring run.
static bool is_run_terminator(wchar_t c) {
return c == L'\0' || c == L'\n' || c == L'\r' || c == L'\f';
}
/// Measure a run of characters in \p input starting at \p start.
/// Stop when we reach a run terminator, and return its index in \p out_end (if not null).
/// Note \0 is a run terminator so there will always be one.
/// We permit escape sequences to have run terminators other than \0. That is, escape sequences may
/// have embedded newlines, etc.; it's unclear if this is possible but we allow it.
static size_t measure_run_from(const wchar_t *input, size_t start, size_t *out_end,
layout_cache_t &cache) {
size_t width = 0;
size_t idx = start;
for (idx = start; !is_run_terminator(input[idx]); idx++) {
if (input[idx] == L'\x1B') {
// This is the start of an escape code; we assume it has width 0.
// -1 because we are going to increment in the loop.
size_t len = cache.escape_code_length(&input[idx]);
if (len > 0) idx += len - 1;
} else if (input[idx] == L'\t') {
width = next_tab_stop(width);
} else {
// Ordinary char. Add its width with care to ignore control chars which have width -1.
width += fish_wcwidth_min_0(input[idx]);
}
}
if (out_end) *out_end = idx;
return width;
}
/// Attempt to truncate the prompt run \p run, which has width \p width, to \p no more than
/// desired_width. \return the resulting width and run by reference.
static void truncate_run(wcstring *run, size_t desired_width, size_t *width,
layout_cache_t &cache) {
size_t curr_width = *width;
if (curr_width <= desired_width) {
return;
}
// Bravely prepend ellipsis char and skip it.
// Ellipsis is always width 1.
wchar_t ellipsis = get_ellipsis_char();
run->insert(0, 1, ellipsis); // index, count, char
curr_width += 1;
// Start removing characters after ellipsis.
// Note we modify 'run' inside this loop.
size_t idx = 1;
while (curr_width > desired_width && idx < run->size()) {
wchar_t c = run->at(idx);
assert(!is_run_terminator(c) && "Should not have run terminator inside run");
if (c == L'\x1B') {
size_t len = cache.escape_code_length(run->c_str() + idx);
idx += std::max(len, (size_t)1);
} else if (c == '\t') {
// Tabs would seem to be quite annoying to measure while truncating.
// We simply remove these and start over.
run->erase(idx, 1);
curr_width = measure_run_from(run->c_str(), 0, nullptr, cache);
idx = 0;
} else {
size_t char_width = fish_wcwidth_min_0(c);
curr_width -= std::min(curr_width, char_width);
run->erase(idx, 1);
}
}
*width = curr_width;
}
prompt_layout_t layout_cache_t::calc_prompt_layout(const wcstring &prompt_str,
wcstring *out_trunc_prompt,
size_t max_line_width) {
// FIXME: we could avoid allocating trunc_prompt if max_line_width is SIZE_T_MAX.
if (const auto *entry = this->find_prompt_layout(prompt_str, max_line_width)) {
if (out_trunc_prompt) out_trunc_prompt->assign(entry->trunc_text);
return entry->layout;
}
size_t prompt_len = prompt_str.size();
const wchar_t *prompt = prompt_str.c_str();
prompt_layout_t layout = {{}, 0, 0};
wcstring trunc_prompt;
size_t run_start = 0;
while (run_start < prompt_len) {
size_t run_end;
size_t line_width = measure_run_from(prompt, run_start, &run_end, *this);
if (line_width <= max_line_width) {
// No truncation needed on this line.
trunc_prompt.append(&prompt[run_start], run_end - run_start);
} else {
// Truncation needed on this line.
wcstring run_storage(&prompt[run_start], run_end - run_start);
truncate_run(&run_storage, max_line_width, &line_width, *this);
trunc_prompt.append(run_storage);
}
layout.max_line_width = std::max(layout.max_line_width, line_width);
layout.last_line_width = line_width;
wchar_t endc = prompt[run_end];
if (endc) {
if (endc == L'\n' || endc == L'\f') {
layout.line_breaks.push_back(trunc_prompt.size());
}
trunc_prompt.push_back(endc);
run_start = run_end + 1;
} else {
break;
}
}
this->add_prompt_layout(prompt_cache_entry_t{prompt, max_line_width, trunc_prompt, layout});
if (out_trunc_prompt) {
*out_trunc_prompt = std::move(trunc_prompt);
}
return layout;
}
static size_t calc_prompt_lines(const wcstring &prompt) {
// Hack for the common case where there's no newline at all. I don't know if a newline can
// appear in an escape sequence, so if we detect a newline we have to defer to
// calc_prompt_width_and_lines.
size_t result = 1;
if (prompt.find_first_of(L"\n\f") != wcstring::npos) {
result = layout_cache_t::shared.calc_prompt_layout(prompt).line_breaks.size() + 1;
}
return result;
}
/// Stat stdout and stderr and save result. This should be done before calling a function that may
/// cause output.
void s_save_status(screen_t *s) {
fstat(STDOUT_FILENO, &s->prev_buff_1);
fstat(STDERR_FILENO, &s->prev_buff_2);
}
/// Stat stdout and stderr and compare result to previous result in reader_save_status. Repaint if
/// modification time has changed.
///
/// Unfortunately, for some reason this call seems to give a lot of false positives, at least under
/// Linux.
static void s_check_status(screen_t *s) {
fflush(stdout);
fflush(stderr);
if (!has_working_tty_timestamps) {
// We can't reliably determine if the terminal has been written to behind our back so we
// just assume that hasn't happened and hope for the best. This is important for multi-line
// prompts to work correctly.
return;
}
struct stat post_buff_1 {};
struct stat post_buff_2 {};
fstat(STDOUT_FILENO, &post_buff_1);
fstat(STDERR_FILENO, &post_buff_2);
bool changed = (s->prev_buff_1.st_mtime != post_buff_1.st_mtime) ||
(s->prev_buff_2.st_mtime != post_buff_2.st_mtime);
#if defined HAVE_STRUCT_STAT_ST_MTIMESPEC_TV_NSEC
changed = changed || s->prev_buff_1.st_mtimespec.tv_nsec != post_buff_1.st_mtimespec.tv_nsec ||
s->prev_buff_2.st_mtimespec.tv_nsec != post_buff_2.st_mtimespec.tv_nsec;
#elif defined HAVE_STRUCT_STAT_ST_MTIM_TV_NSEC
changed = changed || s->prev_buff_1.st_mtim.tv_nsec != post_buff_1.st_mtim.tv_nsec ||
s->prev_buff_2.st_mtim.tv_nsec != post_buff_2.st_mtim.tv_nsec;
#endif
if (changed) {
// Ok, someone has been messing with our screen. We will want to repaint. However, we do not
// know where the cursor is. It is our best bet that we are still on the same line, so we
// move to the beginning of the line, reset the modelled screen contents, and then set the
// modeled cursor y-pos to its earlier value.
int prev_line = s->actual.cursor.y;
s_reset_line(s, true /* repaint prompt */);
s->actual.cursor.y = prev_line;
}
}
/// Appends a character to the end of the line that the output cursor is on. This function
/// automatically handles linebreaks and lines longer than the screen width.
static void s_desired_append_char(screen_t *s, wchar_t b, highlight_spec_t c, int indent,
size_t prompt_width, size_t bwidth) {
int line_no = s->desired.cursor.y;
if (b == L'\n') {
// Current line is definitely hard wrapped.
// Create the next line.
s->desired.create_line(s->desired.cursor.y + 1);
s->desired.line(s->desired.cursor.y).is_soft_wrapped = false;
int line_no = ++s->desired.cursor.y;
s->desired.cursor.x = 0;
size_t indentation = prompt_width + indent * INDENT_STEP;
line_t &line = s->desired.line(line_no);
line.indentation = indentation;
for (size_t i = 0; i < indentation; i++) {
s_desired_append_char(s, L' ', highlight_spec_t{}, indent, prompt_width, 1);
}
} else if (b == L'\r') {
line_t ¤t = s->desired.line(line_no);
current.clear();
s->desired.cursor.x = 0;
} else {
int screen_width = s->desired.screen_width;
int cw = bwidth;
s->desired.create_line(line_no);
// Check if we are at the end of the line. If so, continue on the next line.
if ((s->desired.cursor.x + cw) > screen_width) {
// Current line is soft wrapped (assuming we support it).
s->desired.line(s->desired.cursor.y).is_soft_wrapped = true;
line_no = static_cast<int>(s->desired.line_count());
s->desired.add_line();
s->desired.cursor.y++;
s->desired.cursor.x = 0;
}
line_t &line = s->desired.line(line_no);
line.append(b, c);
s->desired.cursor.x += cw;
// Maybe wrap the cursor to the next line, even if the line itself did not wrap. This
// avoids wonkiness in the last column.
if (s->desired.cursor.x >= screen_width) {
line.is_soft_wrapped = true;
s->desired.cursor.x = 0;
s->desired.cursor.y++;
}
}
}
/// Write the bytes needed to move screen cursor to the specified position to the specified buffer.
/// The actual_cursor field of the specified screen_t will be updated.
///
/// \param s the screen to operate on
/// \param new_x the new x position
/// \param new_y the new y position
static void s_move(screen_t *s, int new_x, int new_y) {
if (s->actual.cursor.x == new_x && s->actual.cursor.y == new_y) return;
const scoped_buffer_t buffering(*s);
// If we are at the end of our window, then either the cursor stuck to the edge or it didn't. We
// don't know! We can fix it up though.
if (s->actual.cursor.x == s->actual.screen_width) {
// Either issue a cr to go back to the beginning of this line, or a nl to go to the
// beginning of the next one, depending on what we think is more efficient.
if (new_y <= s->actual.cursor.y) {
s->outp().push_back('\r');
} else {
s->outp().push_back('\n');
s->actual.cursor.y++;
}
// Either way we're not in the first column.
s->actual.cursor.x = 0;
}
int i;
int x_steps, y_steps;
const char *str;
auto &outp = s->outp();
y_steps = new_y - s->actual.cursor.y;
if (y_steps < 0) {
str = cursor_up;
} else if (y_steps > 0) {
str = cursor_down;
if ((shell_modes.c_oflag & ONLCR) != 0 &&
std::strcmp(str, "\n") == 0) { // See GitHub issue #4505.
// Most consoles use a simple newline as the cursor down escape.
// If ONLCR is enabled (which it normally is) this will of course
// also move the cursor to the beginning of the line.
// We could do:
// if (std::strcmp(cursor_up, "\x1B[A") == 0) str = "\x1B[B";
// else ... but that doesn't work for unknown reasons.
s->actual.cursor.x = 0;
}
}
for (i = 0; i < abs(y_steps); i++) {
writembs(outp, str);
}
x_steps = new_x - s->actual.cursor.x;
if (x_steps && new_x == 0) {
outp.push_back('\r');
x_steps = 0;
}
const char *multi_str = nullptr;
if (x_steps < 0) {
str = cursor_left;
multi_str = parm_left_cursor;
} else {
str = cursor_right;
multi_str = parm_right_cursor;
}
// Use the bulk ('multi') output for cursor movement if it is supported and it would be shorter
// Note that this is required to avoid some visual glitches in iTerm (issue #1448).
bool use_multi = multi_str != nullptr && multi_str[0] != '\0' &&
abs(x_steps) * std::strlen(str) > std::strlen(multi_str);
if (use_multi && cur_term) {
char *multi_param = tparm(const_cast<char *>(multi_str), abs(x_steps));
writembs(outp, multi_param);
} else {
for (i = 0; i < abs(x_steps); i++) {
writembs(outp, str);
}
}
s->actual.cursor.x = new_x;
s->actual.cursor.y = new_y;
}
/// Convert a wide character to a multibyte string and append it to the buffer.
static void s_write_char(screen_t *s, wchar_t c, size_t width) {
scoped_buffer_t outp(*s);
s->actual.cursor.x += width;
s->outp().writech(c);
if (s->actual.cursor.x == s->actual.screen_width && allow_soft_wrap()) {
s->soft_wrap_location = screen_data_t::cursor_t{0, s->actual.cursor.y + 1};
// Note that our cursor position may be a lie: Apple Terminal makes the right cursor stick
// to the margin, while Ubuntu makes it "go off the end" (but still doesn't wrap). We rely
// on s_move to fix this up.
} else {
invalidate_soft_wrap(s);
}
}
/// Send the specified string through tputs and append the output to the screen's outputter.
static void s_write_mbs(screen_t *screen, const char *s) { writembs(screen->outp(), s); }
/// Convert a wide string to a multibyte string and append it to the buffer.
static void s_write_str(screen_t *screen, const wchar_t *s) { screen->outp().writestr(s); }
/// Returns the length of the "shared prefix" of the two lines, which is the run of matching text
/// and colors. If the prefix ends on a combining character, do not include the previous character
/// in the prefix.
static size_t line_shared_prefix(const line_t &a, const line_t &b) {
size_t idx, max = std::min(a.size(), b.size());
for (idx = 0; idx < max; idx++) {
wchar_t ac = a.char_at(idx), bc = b.char_at(idx);
// We're done if the text or colors are different.
if (ac != bc || a.color_at(idx) != b.color_at(idx)) {
if (idx > 0) {
const line_t *c = nullptr;
// Possible combining mark, go back until we hit _two_ printable characters or idx
// of 0.
if (fish_wcwidth(a.char_at(idx)) < 1) {
c = &a;
} else if (fish_wcwidth(b.char_at(idx)) < 1) {
c = &b;
}
if (c) {
while (idx > 1 && (fish_wcwidth(c->char_at(idx - 1)) < 1 ||
fish_wcwidth(c->char_at(idx)) < 1))
idx--;
if (idx == 1 && fish_wcwidth(c->char_at(idx)) < 1) idx = 0;
}
}
break;
}
}
return idx;
}
// We are about to output one or more characters onto the screen at the given x, y. If we are at the
// end of previous line, and the previous line is marked as soft wrapping, then tweak the screen so
// we believe we are already in the target position. This lets the terminal take care of wrapping,
// which means that if you copy and paste the text, it won't have an embedded newline.
static bool perform_any_impending_soft_wrap(screen_t *scr, int x, int y) {
if (scr->soft_wrap_location && x == scr->soft_wrap_location->x &&
y == scr->soft_wrap_location->y) { //!OCLINT
// We can soft wrap; but do we want to?
if (scr->desired.line(y - 1).is_soft_wrapped && allow_soft_wrap()) {
// Yes. Just update the actual cursor; that will cause us to elide emitting the commands
// to move here, so we will just output on "one big line" (which the terminal soft
// wraps.
scr->actual.cursor = scr->soft_wrap_location.value();
}
}
return false;
}
/// Make sure we don't soft wrap.
static void invalidate_soft_wrap(screen_t *scr) { scr->soft_wrap_location = none(); }
/// Update the screen to match the desired output.
static void s_update(screen_t *scr, const wcstring &left_prompt, const wcstring &right_prompt) {
// TODO: this should be passed in.
const environment_t &vars = env_stack_t::principal();
// Helper function to set a resolved color, using the caching resolver.
highlight_color_resolver_t color_resolver{};
auto set_color = [&](highlight_spec_t c) {
scr->outp().set_color(color_resolver.resolve_spec(c, false, vars),
color_resolver.resolve_spec(c, true, vars));
};
layout_cache_t &cached_layouts = layout_cache_t::shared;
const scoped_buffer_t buffering(*scr);
// Determine size of left and right prompt. Note these have already been truncated.
const prompt_layout_t left_prompt_layout = cached_layouts.calc_prompt_layout(left_prompt);
const size_t left_prompt_width = left_prompt_layout.last_line_width;
const size_t right_prompt_width =
cached_layouts.calc_prompt_layout(right_prompt).last_line_width;
// Figure out how many following lines we need to clear (probably 0).
size_t actual_lines_before_reset = scr->actual_lines_before_reset;
scr->actual_lines_before_reset = 0;
bool need_clear_lines = scr->need_clear_lines;
bool need_clear_screen = scr->need_clear_screen;
bool has_cleared_screen = false;
const int screen_width = scr->desired.screen_width;
if (scr->actual.screen_width != screen_width) {
// Ensure we don't issue a clear screen for the very first output, to avoid issue #402.
if (scr->actual.screen_width > 0) {
need_clear_screen = true;
s_move(scr, 0, 0);
s_reset_line(scr);
need_clear_lines = need_clear_lines || scr->need_clear_lines;
need_clear_screen = need_clear_screen || scr->need_clear_screen;
}
scr->actual.screen_width = screen_width;
}
scr->need_clear_lines = false;
scr->need_clear_screen = false;
// Determine how many lines have stuff on them; we need to clear lines with stuff that we don't
// want.
const size_t lines_with_stuff = std::max(actual_lines_before_reset, scr->actual.line_count());
if (scr->desired.line_count() < lines_with_stuff) need_clear_screen = true;
// Output the left prompt if it has changed.
if (left_prompt != scr->actual_left_prompt) {
s_move(scr, 0, 0);
size_t start = 0;
for (const size_t line_break : left_prompt_layout.line_breaks) {
s_write_str(scr, left_prompt.substr(start, line_break - start).c_str());
if (clr_eol) {
s_write_mbs(scr, clr_eol);
}
start = line_break;
}
s_write_str(scr, left_prompt.c_str() + start);
scr->actual_left_prompt = left_prompt;
scr->actual.cursor.x = static_cast<int>(left_prompt_width);
}
// Output all lines.
for (size_t i = 0; i < scr->desired.line_count(); i++) {
const line_t &o_line = scr->desired.line(i);
line_t &s_line = scr->actual.create_line(i);
size_t start_pos = i == 0 ? left_prompt_width : 0;
int current_width = 0;
bool has_cleared_line = false;
// If this is the last line, maybe we should clear the screen.
// Don't issue clr_eos if we think the cursor will end up in the last column - see #6951.
const bool should_clear_screen_this_line =
need_clear_screen && i + 1 == scr->desired.line_count() && clr_eos != nullptr &&
!(scr->desired.cursor.x == 0 &&
scr->desired.cursor.y == static_cast<int>(scr->desired.line_count()));
// skip_remaining is how many columns are unchanged on this line.
// Note that skip_remaining is a width, not a character count.
size_t skip_remaining = start_pos;
const size_t shared_prefix = line_shared_prefix(o_line, s_line);
size_t skip_prefix = shared_prefix;
if (shared_prefix < o_line.indentation) {
if (o_line.indentation > s_line.indentation && !has_cleared_screen && clr_eol &&
clr_eos) {
set_color(highlight_spec_t{});
s_move(scr, 0, static_cast<int>(i));
s_write_mbs(scr, should_clear_screen_this_line ? clr_eos : clr_eol);
has_cleared_screen = should_clear_screen_this_line;
has_cleared_line = true;
}
skip_prefix = o_line.indentation;
}
// Compute how much we should skip. At a minimum we skip over the prompt. But also skip
// over the shared prefix of what we want to output now, and what we output before, to
// avoid repeatedly outputting it.
if (skip_prefix > 0) {
size_t skip_width =
shared_prefix < skip_prefix ? skip_prefix : o_line.wcswidth_min_0(shared_prefix);
if (skip_width > skip_remaining) skip_remaining = skip_width;
}
if (!should_clear_screen_this_line) {
// If we're soft wrapped, and if we're going to change the first character of the next
// line, don't skip over the last two characters so that we maintain soft-wrapping.
if (o_line.is_soft_wrapped && i + 1 < scr->desired.line_count()) {
bool next_line_will_change = true;
if (i + 1 < scr->actual.line_count()) { //!OCLINT
if (line_shared_prefix(scr->desired.line(i + 1), scr->actual.line(i + 1)) > 0) {
next_line_will_change = false;
}
}
if (next_line_will_change) {
skip_remaining =
std::min(skip_remaining, static_cast<size_t>(scr->actual.screen_width - 2));
}
}
}
// Skip over skip_remaining width worth of characters.
size_t j = 0;
for (; j < o_line.size(); j++) {
size_t width = fish_wcwidth_min_0(o_line.char_at(j));
if (skip_remaining < width) break;
skip_remaining -= width;
current_width += width;
}
// Skip over zero-width characters (e.g. combining marks at the end of the prompt).
for (; j < o_line.size(); j++) {
int width = fish_wcwidth_min_0(o_line.char_at(j));
if (width > 0) break;
}
// Now actually output stuff.
for (;; j++) {
bool done = j >= o_line.size();
// Clear the screen if we have not done so yet.
// If we are about to output into the last column, clear the screen first. If we clear
// the screen after we output into the last column, it can erase the last character due
// to the sticky right cursor. If we clear the screen too early, we can defeat soft
// wrapping.
if (should_clear_screen_this_line && !has_cleared_screen &&
(done || j + 1 == static_cast<size_t>(screen_width))) {
set_color(highlight_spec_t{});
s_move(scr, current_width, static_cast<int>(i));
s_write_mbs(scr, clr_eos);
has_cleared_screen = true;
}
if (done) break;
perform_any_impending_soft_wrap(scr, current_width, static_cast<int>(i));
s_move(scr, current_width, static_cast<int>(i));
set_color(o_line.color_at(j));
auto width = fish_wcwidth_min_0(o_line.char_at(j));
s_write_char(scr, o_line.char_at(j), width);
current_width += width;
}
bool clear_remainder = false;
// Clear the remainder of the line if we need to clear and if we didn't write to the end of
// the line. If we did write to the end of the line, the "sticky right edge" (as part of
// auto_right_margin) means that we'll be clearing the last character we wrote!
if (has_cleared_screen || has_cleared_line) {
// Already cleared everything.
clear_remainder = false;
} else if (need_clear_lines && current_width < screen_width) {
clear_remainder = true;
} else if (right_prompt_width < scr->last_right_prompt_width) {
clear_remainder = true;
} else {
// This wcswidth shows up strong in the profile.
// Only do it if the previous line could conceivably be wider.
// That means if it is a prefix of the current one we can skip it.
if (s_line.text.size() != shared_prefix) {
int prev_width = s_line.wcswidth_min_0();
clear_remainder = prev_width > current_width;
}
}
if (clear_remainder && clr_eol) {
set_color(highlight_spec_t{});
s_move(scr, current_width, static_cast<int>(i));
s_write_mbs(scr, clr_eol);
}
// Output any rprompt if this is the first line.
if (i == 0 && right_prompt_width > 0) { //!OCLINT(Use early exit/continue)
s_move(scr, static_cast<int>(screen_width - right_prompt_width), static_cast<int>(i));
set_color(highlight_spec_t{});
s_write_str(scr, right_prompt.c_str());
scr->actual.cursor.x += right_prompt_width;
// We output in the last column. Some terms (Linux) push the cursor further right, past
// the window. Others make it "stick." Since we don't really know which is which, issue
// a cr so it goes back to the left.
//
// However, if the user is resizing the window smaller, then it's possible the cursor
// wrapped. If so, then a cr will go to the beginning of the following line! So instead
// issue a bunch of "move left" commands to get back onto the line, and then jump to the
// front of it.
s_move(scr, scr->actual.cursor.x - static_cast<int>(right_prompt_width),
scr->actual.cursor.y);
s_write_str(scr, L"\r");
scr->actual.cursor.x = 0;
}
}
// Clear remaining lines (if any) if we haven't cleared the screen.
if (!has_cleared_screen && need_clear_screen && clr_eol) {
set_color(highlight_spec_t{});
for (size_t i = scr->desired.line_count(); i < lines_with_stuff; i++) {
s_move(scr, 0, static_cast<int>(i));
s_write_mbs(scr, clr_eol);
}
}
s_move(scr, scr->desired.cursor.x, scr->desired.cursor.y);
set_color(highlight_spec_t{});
// We have now synced our actual screen against our desired screen. Note that this is a big
// assignment!
scr->actual = scr->desired;
scr->last_right_prompt_width = right_prompt_width;
}
/// Returns true if we are using a dumb terminal.
static bool is_dumb() {
if (!cur_term) return true;
return !cursor_up || !cursor_down || !cursor_left || !cursor_right;
}
struct screen_layout_t {
// The left prompt that we're going to use.
wcstring left_prompt;
// How much space to leave for it.
size_t left_prompt_space;
// The right prompt.
wcstring right_prompt;
// The autosuggestion.
wcstring autosuggestion;
};
// Given a vector whose indexes are offsets and whose values are the widths of the string if
// truncated at that offset, return the offset that fits in the given width. Returns
// width_by_offset.size() - 1 if they all fit. The first value in width_by_offset is assumed to be
// 0.
static size_t truncation_offset_for_width(const std::vector<size_t> &width_by_offset,
size_t max_width) {
assert(!width_by_offset.empty() && width_by_offset.at(0) == 0);
size_t i;
for (i = 1; i < width_by_offset.size(); i++) {
if (width_by_offset.at(i) > max_width) break;
}
// i is the first index that did not fit; i-1 is therefore the last that did.
return i - 1;
}
static screen_layout_t compute_layout(screen_t *s, size_t screen_width,
const wcstring &left_untrunc_prompt,
const wcstring &right_untrunc_prompt,
const wcstring &commandline,
const wcstring &autosuggestion_str) {
UNUSED(s);
screen_layout_t result = {};
// Truncate both prompts to screen width (#904).
wcstring left_prompt;
prompt_layout_t left_prompt_layout =
layout_cache_t::shared.calc_prompt_layout(left_untrunc_prompt, &left_prompt, screen_width);
wcstring right_prompt;
prompt_layout_t right_prompt_layout = layout_cache_t::shared.calc_prompt_layout(
right_untrunc_prompt, &right_prompt, screen_width);
size_t left_prompt_width = left_prompt_layout.last_line_width;
size_t right_prompt_width = right_prompt_layout.last_line_width;
if (left_prompt_width + right_prompt_width > screen_width) {
// Nix right_prompt.
right_prompt = L"";
right_prompt_width = 0;
}
// Now we should definitely fit.
assert(left_prompt_width + right_prompt_width <= screen_width);
// Get the width of the first line, and if there is more than one line.
bool multiline = false;
size_t first_line_width = 0;
for (auto c : commandline) {
if (c == L'\n') {
multiline = true;
break;
} else {
first_line_width += fish_wcwidth_min_0(c);
}
}
const size_t first_command_line_width = first_line_width;
// If we have more than one line, ensure we have no autosuggestion.
const wchar_t *autosuggestion = autosuggestion_str.c_str();
size_t autosuggest_total_width = 0;
std::vector<size_t> autosuggest_truncated_widths;
if (multiline) {
autosuggestion = L"";
} else {
autosuggest_truncated_widths.reserve(1 + autosuggestion_str.size());
for (size_t i = 0; autosuggestion[i] != L'\0'; i++) {
autosuggest_truncated_widths.push_back(autosuggest_total_width);
autosuggest_total_width += fish_wcwidth_min_0(autosuggestion[i]);
}
}
// Here are the layouts we try in turn:
//
// 1. Left prompt visible, right prompt visible, command line visible, autosuggestion visible.
//
// 2. Left prompt visible, right prompt visible, command line visible, autosuggestion truncated
// (possibly to zero).
//
// 3. Left prompt visible, right prompt hidden, command line visible, autosuggestion visible
//
// 4. Left prompt visible, right prompt hidden, command line visible, autosuggestion truncated
//
// 5. Newline separator (left prompt visible, right prompt hidden, command line visible,
// autosuggestion visible).
//
// A remark about layout #4: if we've pushed the command line to a new line, why can't we draw
// the right prompt? The issue is resizing: if you resize the window smaller, then the right
// prompt will wrap to the next line. This means that we can't go back to the line that we were
// on, and things turn to chaos very quickly.
size_t calculated_width;
bool done = false;
// Case 1
if (!done) {
calculated_width = left_prompt_width + right_prompt_width + first_command_line_width +
autosuggest_total_width;
if (calculated_width <= screen_width) {
result.left_prompt = left_prompt;
result.left_prompt_space = left_prompt_width;
result.right_prompt = right_prompt;
result.autosuggestion = autosuggestion;
done = true;
}
}
// Case 2. Note that we require strict inequality so that there's always at least one space
// between the left edge and the rprompt.
if (!done) {
calculated_width = left_prompt_width + right_prompt_width + first_command_line_width;
if (calculated_width <= screen_width) {
result.left_prompt = left_prompt;
result.left_prompt_space = left_prompt_width;
result.right_prompt = right_prompt;
// Need at least two characters to show an autosuggestion.
size_t available_autosuggest_space =
screen_width - (left_prompt_width + right_prompt_width + first_command_line_width);
if (autosuggest_total_width > 0 && available_autosuggest_space > 2) {
size_t truncation_offset = truncation_offset_for_width(
autosuggest_truncated_widths, available_autosuggest_space - 2);
result.autosuggestion = wcstring(autosuggestion, truncation_offset);
result.autosuggestion.push_back(get_ellipsis_char());
}
done = true;
}
}
// Case 3
if (!done) {
calculated_width = left_prompt_width + first_command_line_width + autosuggest_total_width;
if (calculated_width <= screen_width) {
result.left_prompt = left_prompt;
result.left_prompt_space = left_prompt_width;
result.autosuggestion = autosuggestion;
done = true;
}
}
// Case 4
if (!done) {
calculated_width = left_prompt_width + first_command_line_width;
if (calculated_width <= screen_width) {
result.left_prompt = left_prompt;
result.left_prompt_space = left_prompt_width;
// Need at least two characters to show an autosuggestion.
size_t available_autosuggest_space =
screen_width - (left_prompt_width + first_command_line_width);
if (autosuggest_total_width > 0 && available_autosuggest_space > 2) {
size_t truncation_offset = truncation_offset_for_width(
autosuggest_truncated_widths, available_autosuggest_space - 2);
result.autosuggestion = wcstring(autosuggestion, truncation_offset);
result.autosuggestion.push_back(get_ellipsis_char());
}
done = true;
}
}
// Case 5
if (!done) {
result.left_prompt = left_prompt;
result.left_prompt_space = left_prompt_width;
result.autosuggestion = autosuggestion;
}
return result;
}
void s_write(screen_t *s, const wcstring &left_prompt, const wcstring &right_prompt,
const wcstring &commandline, size_t explicit_len,
const std::vector<highlight_spec_t> &colors, const std::vector<int> &indent,
size_t cursor_pos, pager_t &pager, page_rendering_t &page_rendering,
bool cursor_is_within_pager) {
termsize_t curr_termsize = termsize_last();
int screen_width = curr_termsize.width;
static relaxed_atomic_t<uint32_t> s_repaints{0};
FLOGF(screen, "Repaint %u", static_cast<unsigned>(++s_repaints));
screen_data_t::cursor_t cursor_arr;
// Turn the command line into the explicit portion and the autosuggestion.
const wcstring explicit_command_line = commandline.substr(0, explicit_len);
const wcstring autosuggestion = commandline.substr(explicit_len);
// If we are using a dumb terminal, don't try any fancy stuff, just print out the text.
// right_prompt not supported.
if (is_dumb()) {
const std::string prompt_narrow = wcs2string(left_prompt);
const std::string command_line_narrow = wcs2string(explicit_command_line);
write_loop(STDOUT_FILENO, "\r", 1);
write_loop(STDOUT_FILENO, prompt_narrow.c_str(), prompt_narrow.size());
write_loop(STDOUT_FILENO, command_line_narrow.c_str(), command_line_narrow.size());
return;
}
s_check_status(s);
// Completely ignore impossibly small screens.
if (screen_width < 4) {
return;
}
// Compute a layout.
const screen_layout_t layout = compute_layout(s, screen_width, left_prompt, right_prompt,
explicit_command_line, autosuggestion);
// Determine whether, if we have an autosuggestion, it was truncated.
s->autosuggestion_is_truncated =
!autosuggestion.empty() && autosuggestion != layout.autosuggestion;
// Clear the desired screen and set its width.
s->desired.screen_width = screen_width;
s->desired.resize(0);
s->desired.cursor.x = s->desired.cursor.y = 0;
// Append spaces for the left prompt.
for (size_t i = 0; i < layout.left_prompt_space; i++) {
s_desired_append_char(s, L' ', highlight_spec_t{}, 0, layout.left_prompt_space, 1);
}
// If overflowing, give the prompt its own line to improve the situation.
size_t first_line_prompt_space = layout.left_prompt_space;
// Reconstruct the command line.
wcstring effective_commandline = explicit_command_line + layout.autosuggestion;
// Output the command line.
size_t i;
for (i = 0; i < effective_commandline.size(); i++) {
// Grab the current cursor's x,y position if this character matches the cursor's offset.
if (!cursor_is_within_pager && i == cursor_pos) {
cursor_arr = s->desired.cursor;
}
s_desired_append_char(s, effective_commandline.at(i), colors[i], indent[i],
first_line_prompt_space,
fish_wcwidth_min_0(effective_commandline.at(i)));
}
// Cursor may have been at the end too.
if (!cursor_is_within_pager && i == cursor_pos) {
cursor_arr = s->desired.cursor;
}
// Now that we've output everything, set the cursor to the position that we saved in the loop
// above.
s->desired.cursor = cursor_arr;
if (cursor_is_within_pager) {
s->desired.cursor.x = static_cast<int>(cursor_pos);
s->desired.cursor.y = static_cast<int>(s->desired.line_count());
}
// Re-render our completions page if necessary. Limit the term size of the pager to the true
// term size, minus the number of lines consumed by our string.
int full_line_count = cursor_arr.y + 1;
pager.set_term_size(termsize_t{std::max(1, curr_termsize.width),
std::max(1, curr_termsize.height - full_line_count)});
pager.update_rendering(&page_rendering);
// Append pager_data (none if empty).
s->desired.append_lines(page_rendering.screen_data);
s_update(s, layout.left_prompt, layout.right_prompt);
s_save_status(s);
}
void s_reset_line(screen_t *s, bool repaint_prompt) {
assert(s && "Null screen");
// Remember how many lines we had output to, so we can clear the remaining lines in the next
// call to s_update. This prevents leaving junk underneath the cursor when resizing a window
// wider such that it reduces our desired line count.
s->actual_lines_before_reset = std::max(s->actual_lines_before_reset, s->actual.line_count());
if (repaint_prompt) {
// If the prompt is multi-line, we need to move up to the prompt's initial line. We do this
// by lying to ourselves and claiming that we're really below what we consider "line 0"
// (which is the last line of the prompt). This will cause us to move up to try to get back
// to line 0, but really we're getting back to the initial line of the prompt.
const size_t prompt_line_count = calc_prompt_lines(s->actual_left_prompt);
assert(prompt_line_count >= 1);
s->actual.cursor.y += (prompt_line_count - 1);
s->actual_left_prompt.clear();
}
s->actual.resize(0);
s->need_clear_lines = true;
// This should prevent resetting the cursor position during the next repaint.
write_loop(STDOUT_FILENO, "\r", 1);
s->actual.cursor.x = 0;
fstat(STDOUT_FILENO, &s->prev_buff_1);
fstat(STDERR_FILENO, &s->prev_buff_2);
}
void s_reset_abandoning_line(screen_t *s, int screen_width) {
assert(s && "Null screen");
s->actual.cursor.y = 0;
s->actual.resize(0);
s->actual_left_prompt.clear();
s->need_clear_lines = true;
// Do the PROMPT_SP hack.
wcstring abandon_line_string;
abandon_line_string.reserve(screen_width + 32);
// Don't need to check for fish_wcwidth errors; this is done when setting up
// omitted_newline_char in common.cpp.
int non_space_width = get_omitted_newline_width();
// We do `>` rather than `>=` because the code below might require one extra space.
if (screen_width > non_space_width) {
bool justgrey = true;
if (cur_term && enter_dim_mode) {
std::string dim = tparm(const_cast<char *>(enter_dim_mode));
if (!dim.empty()) {
// Use dim if they have it, so the color will be based on their actual normal
// color and the background of the termianl.
abandon_line_string.append(str2wcstring(dim));
justgrey = false;
}
}
if (cur_term && justgrey && set_a_foreground) {
if (max_colors >= 238) {
// draw the string in a particular grey
abandon_line_string.append(
str2wcstring(tparm(const_cast<char *>(set_a_foreground), 237)));
} else if (max_colors >= 9) {
// bright black (the ninth color, looks grey)
abandon_line_string.append(
str2wcstring(tparm(const_cast<char *>(set_a_foreground), 8)));
} else if (max_colors >= 2 && enter_bold_mode) {
// we might still get that color by setting black and going bold for bright
abandon_line_string.append(
str2wcstring(tparm(const_cast<char *>(enter_bold_mode))));
abandon_line_string.append(
str2wcstring(tparm(const_cast<char *>(set_a_foreground), 0)));
}
}
abandon_line_string.append(get_omitted_newline_str());
if (cur_term && exit_attribute_mode) {
abandon_line_string.append(str2wcstring(tparm(
const_cast<char *>(exit_attribute_mode)))); // normal text ANSI escape sequence
}
int newline_glitch_width = term_has_xn ? 0 : 1;
abandon_line_string.append(screen_width - non_space_width - newline_glitch_width, L' ');
}
abandon_line_string.push_back(L'\r');
abandon_line_string.append(get_omitted_newline_str());
// Now we are certainly on a new line. But we may have dropped the omitted newline char on
// it. So append enough spaces to overwrite the omitted newline char, and then clear all the
// spaces from the new line.
abandon_line_string.append(non_space_width, L' ');
abandon_line_string.push_back(L'\r');
// Clear entire line. Zsh doesn't do this. Fish added this with commit 4417a6ee: If you have
// a prompt preceded by a new line, you'll get a line full of spaces instead of an empty
// line above your prompt. This doesn't make a difference in normal usage, but copying and
// pasting your terminal log becomes a pain. This commit clears that line, making it an
// actual empty line.
if (!is_dumb() && clr_eol) {
abandon_line_string.append(str2wcstring(clr_eol));
}
const std::string narrow_abandon_line_string = wcs2string(abandon_line_string);
write_loop(STDOUT_FILENO, narrow_abandon_line_string.c_str(),
narrow_abandon_line_string.size());
s->actual.cursor.x = 0;
fstat(STDOUT_FILENO, &s->prev_buff_1);
fstat(STDERR_FILENO, &s->prev_buff_2);
}
void screen_force_clear_to_end() {
if (clr_eos) {
writembs(outputter_t::stdoutput(), clr_eos);
}
}
screen_t::screen_t() : outp_(outputter_t::stdoutput()) {}
bool screen_t::cursor_is_wrapped_to_own_line() const {
// Note == comparison against the line count is correct: we do not create a line just for the
// cursor. If there is a line containing the cursor, then it means that line has contents and we
// should return false.
// Don't consider dumb terminals to have wrapping for the purposes of this function.
return actual.cursor.x == 0 && static_cast<size_t>(actual.cursor.y) == actual.line_count() &&
!is_dumb();
}