8ef801b40
Denis Vlasenko
2008-10-16
Subject
vi: a few trivial optimizations to keyboard reading code; bump timeout to 50s.
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editors/vi.c+29 -18
| @@ -629,12 +629,12 @@ static void edit_file(char *fn) | |
| } | |
| #endif | |
| do_cmd(c); // execute the user command | |
| - | // |
| + | |
| // poll to see if there is input already waiting. if we are | |
| // not able to display output fast enough to keep up, skip | |
| // the display update until we catch up with input. | |
| - | if (mysleep(0) == 0) { |
| - | // no input pending- so update output |
| + | if (!chars_to_parse && mysleep(0) == 0) { |
| + | // no input pending - so update output |
| refresh(FALSE); | |
| show_status_line(); | |
| } | |
| @@ -2243,8 +2243,10 @@ static char readit(void) // read (maybe cursor) key from stdin | |
| n = chars_to_parse; | |
| if (n == 0) { | |
| - | // If no data, block waiting for input. |
| - | n = safe_read(0, readbuffer, 1); |
| + | // If no data, block waiting for input |
| + | // (can't read more than minimal ESC sequence - |
| + | // see "n = 0" below). |
| + | n = safe_read(0, readbuffer, 3); |
| if (n <= 0) { | |
| error: | |
| go_bottom_and_clear_to_eol(); | |
| @@ -2264,25 +2266,29 @@ static char readit(void) // read (maybe cursor) key from stdin | |
| // If it's an escape sequence, loop through known matches. | |
| if (c == 27) { | |
| const struct esc_cmds *eindex; | |
| + | struct pollfd pfd; |
| + | pfd.fd = STDIN_FILENO; |
| + | pfd.events = POLLIN; |
| for (eindex = esccmds; eindex < esccmds + ARRAY_SIZE(esccmds); eindex++) { | |
| - | // n - position in seq to read |
| - | int i = 0; // position in seq to compare |
| - | int cnt = strnlen(eindex->seq, 4); |
| + | // n - position in sequence we did not read yet |
| + | int i = 0; // position in sequence to compare |
| - | // Loop through chars in this sequence. |
| + | // Loop through chars in this sequence |
| for (;;) { | |
| - | // We've matched this escape sequence up to [i-1] |
| + | // So far escape sequence matches up to [i-1] |
| if (n <= i) { | |
| // Need more chars, read another one if it wouldn't block. | |
| // (Note that escape sequences come in as a unit, | |
| // so if we would block it's not really an escape sequence.) | |
| - | struct pollfd pfd; |
| - | pfd.fd = 0; |
| - | pfd.events = POLLIN; |
| - | // Timeout is needed to reconnect escape sequences split |
| - | // up by transmission over a serial console. |
| - | if (safe_poll(&pfd, 1, 25)) { |
| + | |
| + | // Timeout is needed to reconnect escape sequences |
| + | // split up by transmission over a serial console. |
| + | // Even though inter-char delay on 1200 baud is <10ms, |
| + | // process scheduling can enlarge it arbitrarily, |
| + | // on both send and receive sides. |
| + | // Erring on the safe side - 5 timer ticks on 100 HZ. |
| + | if (safe_poll(&pfd, 1, 50)) { |
| if (safe_read(0, readbuffer + n, 1) <= 0) | |
| goto error; | |
| n++; | |
| @@ -2296,9 +2302,14 @@ static char readit(void) // read (maybe cursor) key from stdin | |
| } | |
| if (readbuffer[i] != eindex->seq[i]) | |
| break; // try next seq | |
| - | if (++i == cnt) { // entire seq matched |
| + | i++; |
| + | if (i == 4 || !eindex->seq[i]) { // entire seq matched |
| c = eindex->val; | |
| n = 0; | |
| + | // n -= i; memmove(...); |
| + | // would be more correct, |
| + | // but we never read ahead that much, |
| + | // and n == i here. |
| goto loop_out; | |
| } | |
| } | |
| @@ -2306,7 +2317,7 @@ static char readit(void) // read (maybe cursor) key from stdin | |
| // We did not find matching sequence, it was a bare ESC. | |
| // We possibly read and stored more input in readbuffer by now. | |
| } | |
| - | loop_out: |
| + | loop_out: |
| chars_to_parse = n; | |
| return c; | |