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Diffstat (limited to 'patches/st-appsync-20200618-b27a383.diff')
| -rw-r--r-- | patches/st-appsync-20200618-b27a383.diff | 259 |
1 files changed, 259 insertions, 0 deletions
diff --git a/patches/st-appsync-20200618-b27a383.diff b/patches/st-appsync-20200618-b27a383.diff new file mode 100644 index 0000000..4736325 --- /dev/null +++ b/patches/st-appsync-20200618-b27a383.diff @@ -0,0 +1,259 @@ +From 8c9c920325fa10440a96736ba58ec647a0365e22 Mon Sep 17 00:00:00 2001 +From: "Avi Halachmi (:avih)" <avihpit@yahoo.com> +Date: Sat, 18 Apr 2020 13:56:11 +0300 +Subject: [PATCH] application-sync: support Synchronized-Updates + +See https://gitlab.com/gnachman/iterm2/-/wikis/synchronized-updates-spec + +In a nutshell: allow an application to suspend drawing until it has +completed some output - so that the terminal will not flicker/tear by +rendering partial content. If the end-of-suspension sequence doesn't +arrive, the terminal bails out after a timeout (default: 200 ms). + +The feature is supported and pioneered by iTerm2. There are probably +very few other terminals or applications which support this feature +currently. + +One notable application which does support it is tmux (master as of +2020-04-18) - where cursor flicker is completely avoided when a pane +has new content. E.g. run in one pane: `while :; do cat x.c; done' +while the cursor is at another pane. + +The terminfo string `Sync' added to `st.info' is also a tmux extension +which tmux detects automatically when `st.info` is installed. + +Notes: + +- Draw-suspension begins on BSU sequence (Begin-Synchronized-Update), + and ends on ESU sequence (End-Synchronized-Update). + +- BSU, ESU are "\033P=1s\033\\", "\033P=2s\033\\" respectively (DCS). + +- SU doesn't support nesting - BSU begins or extends, ESU always ends. + +- ESU without BSU is ignored. + +- BSU after BSU extends (resets the timeout), so an application could + send BSU in a loop and keep drawing suspended - exactly like it can + not-draw anything in a loop. But as soon as it exits/aborted then + drawing is resumed according to the timeout even without ESU. + +- This implementation focuses on ESU and doesn't really care about BSU + in the sense that it tries hard to draw exactly once ESU arrives (if + it's not too soon after the last draw - according to minlatency), + and doesn't try to draw the content just up-to BSU. These two sides + complement eachother - not-drawing on BSU increases the chance that + ESU is not too soon after the last draw. This approach was chosen + because the application's main focus is that ESU indicates to the + terminal that the content is now ready - and that's when we try to + draw. +--- + config.def.h | 6 ++++++ + st.c | 48 ++++++++++++++++++++++++++++++++++++++++++++++-- + st.info | 1 + + x.c | 22 +++++++++++++++++++--- + 4 files changed, 72 insertions(+), 5 deletions(-) + +diff --git a/config.def.h b/config.def.h +index 6f05dce..80d768e 100644 +--- a/config.def.h ++++ b/config.def.h +@@ -56,6 +56,12 @@ int allowwindowops = 0; + static double minlatency = 8; + static double maxlatency = 33; + ++/* ++ * Synchronized-Update timeout in ms ++ * https://gitlab.com/gnachman/iterm2/-/wikis/synchronized-updates-spec ++ */ ++static uint su_timeout = 200; ++ + /* + * blinking timeout (set to 0 to disable blinking) for the terminal blinking + * attribute. +diff --git a/st.c b/st.c +index 76b7e0d..0582e77 100644 +--- a/st.c ++++ b/st.c +@@ -231,6 +231,33 @@ static uchar utfmask[UTF_SIZ + 1] = {0xC0, 0x80, 0xE0, 0xF0, 0xF8}; + static Rune utfmin[UTF_SIZ + 1] = { 0, 0, 0x80, 0x800, 0x10000}; + static Rune utfmax[UTF_SIZ + 1] = {0x10FFFF, 0x7F, 0x7FF, 0xFFFF, 0x10FFFF}; + ++#include <time.h> ++static int su = 0; ++struct timespec sutv; ++ ++static void ++tsync_begin() ++{ ++ clock_gettime(CLOCK_MONOTONIC, &sutv); ++ su = 1; ++} ++ ++static void ++tsync_end() ++{ ++ su = 0; ++} ++ ++int ++tinsync(uint timeout) ++{ ++ struct timespec now; ++ if (su && !clock_gettime(CLOCK_MONOTONIC, &now) ++ && TIMEDIFF(now, sutv) >= timeout) ++ su = 0; ++ return su; ++} ++ + ssize_t + xwrite(int fd, const char *s, size_t len) + { +@@ -818,6 +845,9 @@ ttynew(char *line, char *cmd, char *out, char **args) + return cmdfd; + } + ++static int twrite_aborted = 0; ++int ttyread_pending() { return twrite_aborted; } ++ + size_t + ttyread(void) + { +@@ -826,7 +856,7 @@ ttyread(void) + int ret, written; + + /* append read bytes to unprocessed bytes */ +- ret = read(cmdfd, buf+buflen, LEN(buf)-buflen); ++ ret = twrite_aborted ? 1 : read(cmdfd, buf+buflen, LEN(buf)-buflen); + + switch (ret) { + case 0: +@@ -834,7 +864,7 @@ ttyread(void) + case -1: + die("couldn't read from shell: %s\n", strerror(errno)); + default: +- buflen += ret; ++ buflen += twrite_aborted ? 0 : ret; + written = twrite(buf, buflen, 0); + buflen -= written; + /* keep any incomplete UTF-8 byte sequence for the next call */ +@@ -994,6 +1024,7 @@ tsetdirtattr(int attr) + void + tfulldirt(void) + { ++ tsync_end(); + tsetdirt(0, term.row-1); + } + +@@ -1895,6 +1926,12 @@ strhandle(void) + xsettitle(strescseq.args[0]); + return; + case 'P': /* DCS -- Device Control String */ ++ /* https://gitlab.com/gnachman/iterm2/-/wikis/synchronized-updates-spec */ ++ if (strstr(strescseq.buf, "=1s") == strescseq.buf) ++ tsync_begin(); /* BSU */ ++ else if (strstr(strescseq.buf, "=2s") == strescseq.buf) ++ tsync_end(); /* ESU */ ++ return; + case '_': /* APC -- Application Program Command */ + case '^': /* PM -- Privacy Message */ + return; +@@ -2436,6 +2473,9 @@ twrite(const char *buf, int buflen, int show_ctrl) + Rune u; + int n; + ++ int su0 = su; ++ twrite_aborted = 0; ++ + for (n = 0; n < buflen; n += charsize) { + if (IS_SET(MODE_UTF8)) { + /* process a complete utf8 char */ +@@ -2446,6 +2486,10 @@ twrite(const char *buf, int buflen, int show_ctrl) + u = buf[n] & 0xFF; + charsize = 1; + } ++ if (su0 && !su) { ++ twrite_aborted = 1; ++ break; // ESU - allow rendering before a new BSU ++ } + if (show_ctrl && ISCONTROL(u)) { + if (u & 0x80) { + u &= 0x7f; +diff --git a/st.info b/st.info +index 8201ad6..b32b446 100644 +--- a/st.info ++++ b/st.info +@@ -191,6 +191,7 @@ st-mono| simpleterm monocolor, + Ms=\E]52;%p1%s;%p2%s\007, + Se=\E[2 q, + Ss=\E[%p1%d q, ++ Sync=\EP=%p1%ds\E\\, + + st| simpleterm, + use=st-mono, +diff --git a/x.c b/x.c +index 210f184..27ff4e2 100644 +--- a/x.c ++++ b/x.c +@@ -1861,6 +1861,9 @@ resize(XEvent *e) + cresize(e->xconfigure.width, e->xconfigure.height); + } + ++int tinsync(uint); ++int ttyread_pending(); ++ + void + run(void) + { +@@ -1895,7 +1898,7 @@ run(void) + FD_SET(ttyfd, &rfd); + FD_SET(xfd, &rfd); + +- if (XPending(xw.dpy)) ++ if (XPending(xw.dpy) || ttyread_pending()) + timeout = 0; /* existing events might not set xfd */ + + seltv.tv_sec = timeout / 1E3; +@@ -1909,7 +1912,8 @@ run(void) + } + clock_gettime(CLOCK_MONOTONIC, &now); + +- if (FD_ISSET(ttyfd, &rfd)) ++ int ttyin = FD_ISSET(ttyfd, &rfd) || ttyread_pending(); ++ if (ttyin) + ttyread(); + + xev = 0; +@@ -1933,7 +1937,7 @@ run(void) + * maximum latency intervals during `cat huge.txt`, and perfect + * sync with periodic updates from animations/key-repeats/etc. + */ +- if (FD_ISSET(ttyfd, &rfd) || xev) { ++ if (ttyin || xev) { + if (!drawing) { + trigger = now; + drawing = 1; +@@ -1944,6 +1948,18 @@ run(void) + continue; /* we have time, try to find idle */ + } + ++ if (tinsync(su_timeout)) { ++ /* ++ * on synchronized-update draw-suspension: don't reset ++ * drawing so that we draw ASAP once we can (just after ++ * ESU). it won't be too soon because we already can ++ * draw now but we skip. we set timeout > 0 to draw on ++ * SU-timeout even without new content. ++ */ ++ timeout = minlatency; ++ continue; ++ } ++ + /* idle detected or maxlatency exhausted -> draw */ + timeout = -1; + if (blinktimeout && tattrset(ATTR_BLINK)) { + +base-commit: b27a383a3acc7decf00e6e889fca265430b5d329 +-- +2.17.1 + |