Andrew's git - gitweb.git/blob

   1#include "cache.h"
   2#include "run-command.h"
   3#include "sigchain.h"
   4
   5#ifndef DEFAULT_PAGER
   6#define DEFAULT_PAGER "less"
   7#endif
   8
   9/*
  10 * This is split up from the rest of git so that we can do
  11 * something different on Windows.
  12 */
  13
  14static const char *pager_argv[] = { NULL, NULL };
  15static struct child_process pager_process;
  16
  17static void wait_for_pager(void)
  18{
  19        fflush(stdout);
  20        fflush(stderr);
  21        /* signal EOF to pager */
  22        close(1);
  23        close(2);
  24        finish_command(&pager_process);
  25}
  26
  27static void wait_for_pager_signal(int signo)
  28{
  29        wait_for_pager();
  30        sigchain_pop(signo);
  31        raise(signo);
  32}
  33
  34const char *git_pager(int stdout_is_tty)
  35{
  36        const char *pager;
  37
  38        if (!stdout_is_tty)
  39                return NULL;
  40
  41        pager = getenv("GIT_PAGER");
  42        if (!pager) {
  43                if (!pager_program)
  44                        git_config(git_default_config, NULL);
  45                pager = pager_program;
  46        }
  47        if (!pager)
  48                pager = getenv("PAGER");
  49        if (!pager)
  50                pager = DEFAULT_PAGER;
  51        else if (!*pager || !strcmp(pager, "cat"))
  52                pager = NULL;
  53
  54        return pager;
  55}
  56
  57void setup_pager(void)
  58{
  59        const char *pager = git_pager(isatty(1));
  60
  61        if (!pager || pager_in_use())
  62                return;
  63
  64        /*
  65         * force computing the width of the terminal before we redirect
  66         * the standard output to the pager.
  67         */
  68        (void) term_columns();
  69
  70        setenv("GIT_PAGER_IN_USE", "true", 1);
  71
  72        /* spawn the pager */
  73        pager_argv[0] = pager;
  74        pager_process.use_shell = 1;
  75        pager_process.argv = pager_argv;
  76        pager_process.in = -1;
  77        if (!getenv("LESS")) {
  78                static const char *env[] = { "LESS=FRSX", NULL };
  79                pager_process.env = env;
  80        }
  81        if (start_command(&pager_process))
  82                return;
  83
  84        /* original process continues, but writes to the pipe */
  85        dup2(pager_process.in, 1);
  86        if (isatty(2))
  87                dup2(pager_process.in, 2);
  88        close(pager_process.in);
  89
  90        /* this makes sure that the parent terminates after the pager */
  91        sigchain_push_common(wait_for_pager_signal);
  92        atexit(wait_for_pager);
  93}
  94
  95int pager_in_use(void)
  96{
  97        const char *env;
  98        env = getenv("GIT_PAGER_IN_USE");
  99        return env ? git_config_bool("GIT_PAGER_IN_USE", env) : 0;
 100}
 101
 102/*
 103 * Return cached value (if set) or $COLUMNS environment variable (if
 104 * set and positive) or ioctl(1, TIOCGWINSZ).ws_col (if positive),
 105 * and default to 80 if all else fails.
 106 */
 107int term_columns(void)
 108{
 109        static int term_columns_at_startup;
 110
 111        char *col_string;
 112        int n_cols;
 113
 114        if (term_columns_at_startup)
 115                return term_columns_at_startup;
 116
 117        term_columns_at_startup = 80;
 118
 119        col_string = getenv("COLUMNS");
 120        if (col_string && (n_cols = atoi(col_string)) > 0)
 121                term_columns_at_startup = n_cols;
 122#ifdef TIOCGWINSZ
 123        else {
 124                struct winsize ws;
 125                if (!ioctl(1, TIOCGWINSZ, &ws) && ws.ws_col)
 126                        term_columns_at_startup = ws.ws_col;
 127        }
 128#endif
 129
 130        return term_columns_at_startup;
 131}
 132
 133/*
 134 * How many columns do we need to show this number in decimal?
 135 */
 136int decimal_width(int number)
 137{
 138        int i, width;
 139
 140        for (width = 1, i = 10; i <= number; width++)
 141                i *= 10;
 142        return width;
 143}