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
  14#ifndef WIN32
  15static void pager_preexec(void)
  16{
  17        /*
  18         * Work around bug in "less" by not starting it until we
  19         * have real input
  20         */
  21        fd_set in;
  22
  23        FD_ZERO(&in);
  24        FD_SET(0, &in);
  25        select(1, &in, NULL, &in, NULL);
  26}
  27#endif
  28
  29static const char *pager_argv[] = { NULL, NULL };
  30static struct child_process pager_process;
  31
  32static void wait_for_pager(void)
  33{
  34        fflush(stdout);
  35        fflush(stderr);
  36        /* signal EOF to pager */
  37        close(1);
  38        close(2);
  39        finish_command(&pager_process);
  40}
  41
  42static void wait_for_pager_signal(int signo)
  43{
  44        wait_for_pager();
  45        sigchain_pop(signo);
  46        raise(signo);
  47}
  48
  49const char *git_pager(int stdout_is_tty)
  50{
  51        const char *pager;
  52
  53        if (!stdout_is_tty)
  54                return NULL;
  55
  56        pager = getenv("GIT_PAGER");
  57        if (!pager) {
  58                if (!pager_program)
  59                        git_config(git_default_config, NULL);
  60                pager = pager_program;
  61        }
  62        if (!pager)
  63                pager = getenv("PAGER");
  64        if (!pager)
  65                pager = DEFAULT_PAGER;
  66        else if (!*pager || !strcmp(pager, "cat"))
  67                pager = NULL;
  68
  69        return pager;
  70}
  71
  72void setup_pager(void)
  73{
  74        const char *pager = git_pager(isatty(1));
  75
  76        if (!pager || pager_in_use())
  77                return;
  78
  79        /*
  80         * force computing the width of the terminal before we redirect
  81         * the standard output to the pager.
  82         */
  83        (void) term_columns();
  84
  85        setenv("GIT_PAGER_IN_USE", "true", 1);
  86
  87        /* spawn the pager */
  88        pager_argv[0] = pager;
  89        pager_process.use_shell = 1;
  90        pager_process.argv = pager_argv;
  91        pager_process.in = -1;
  92        if (!getenv("LESS")) {
  93                static const char *env[] = { "LESS=FRSX", NULL };
  94                pager_process.env = env;
  95        }
  96#ifndef WIN32
  97        pager_process.preexec_cb = pager_preexec;
  98#endif
  99        if (start_command(&pager_process))
 100                return;
 101
 102        /* original process continues, but writes to the pipe */
 103        dup2(pager_process.in, 1);
 104        if (isatty(2))
 105                dup2(pager_process.in, 2);
 106        close(pager_process.in);
 107
 108        /* this makes sure that the parent terminates after the pager */
 109        sigchain_push_common(wait_for_pager_signal);
 110        atexit(wait_for_pager);
 111}
 112
 113int pager_in_use(void)
 114{
 115        const char *env;
 116        env = getenv("GIT_PAGER_IN_USE");
 117        return env ? git_config_bool("GIT_PAGER_IN_USE", env) : 0;
 118}
 119
 120/*
 121 * Return cached value (if set) or $COLUMNS environment variable (if
 122 * set and positive) or ioctl(1, TIOCGWINSZ).ws_col (if positive),
 123 * and default to 80 if all else fails.
 124 */
 125int term_columns(void)
 126{
 127        static int term_columns_at_startup;
 128
 129        char *col_string;
 130        int n_cols;
 131
 132        if (term_columns_at_startup)
 133                return term_columns_at_startup;
 134
 135        term_columns_at_startup = 80;
 136
 137        col_string = getenv("COLUMNS");
 138        if (col_string && (n_cols = atoi(col_string)) > 0)
 139                term_columns_at_startup = n_cols;
 140#ifdef TIOCGWINSZ
 141        else {
 142                struct winsize ws;
 143                if (!ioctl(1, TIOCGWINSZ, &ws) && ws.ws_col)
 144                        term_columns_at_startup = ws.ws_col;
 145        }
 146#endif
 147
 148        return term_columns_at_startup;
 149}
 150
 151/*
 152 * How many columns do we need to show this number in decimal?
 153 */
 154int decimal_width(int number)
 155{
 156        int i, width;
 157
 158        for (width = 1, i = 10; i <= number; width++)
 159                i *= 10;
 160        return width;
 161}