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
   9struct pager_config {
  10        const char *cmd;
  11        int want;
  12        char *value;
  13};
  14
  15/*
  16 * This is split up from the rest of git so that we can do
  17 * something different on Windows.
  18 */
  19
  20static const char *pager_argv[] = { NULL, NULL };
  21static struct child_process pager_process;
  22
  23static void wait_for_pager(void)
  24{
  25        fflush(stdout);
  26        fflush(stderr);
  27        /* signal EOF to pager */
  28        close(1);
  29        close(2);
  30        finish_command(&pager_process);
  31}
  32
  33static void wait_for_pager_signal(int signo)
  34{
  35        wait_for_pager();
  36        sigchain_pop(signo);
  37        raise(signo);
  38}
  39
  40const char *git_pager(int stdout_is_tty)
  41{
  42        const char *pager;
  43
  44        if (!stdout_is_tty)
  45                return NULL;
  46
  47        pager = getenv("GIT_PAGER");
  48        if (!pager) {
  49                if (!pager_program)
  50                        git_config(git_default_config, NULL);
  51                pager = pager_program;
  52        }
  53        if (!pager)
  54                pager = getenv("PAGER");
  55        if (!pager)
  56                pager = DEFAULT_PAGER;
  57        if (!*pager || !strcmp(pager, "cat"))
  58                pager = NULL;
  59
  60        return pager;
  61}
  62
  63void setup_pager(void)
  64{
  65        const char *pager = git_pager(isatty(1));
  66
  67        if (!pager || pager_in_use())
  68                return;
  69
  70        /*
  71         * force computing the width of the terminal before we redirect
  72         * the standard output to the pager.
  73         */
  74        (void) term_columns();
  75
  76        setenv("GIT_PAGER_IN_USE", "true", 1);
  77
  78        /* spawn the pager */
  79        pager_argv[0] = pager;
  80        pager_process.use_shell = 1;
  81        pager_process.argv = pager_argv;
  82        pager_process.in = -1;
  83        if (!getenv("LESS") || !getenv("LV")) {
  84                static const char *env[3];
  85                int i = 0;
  86
  87                if (!getenv("LESS"))
  88                        env[i++] = "LESS=FRSX";
  89                if (!getenv("LV"))
  90                        env[i++] = "LV=-c";
  91                env[i] = NULL;
  92                pager_process.env = env;
  93        }
  94        if (start_command(&pager_process))
  95                return;
  96
  97        /* original process continues, but writes to the pipe */
  98        dup2(pager_process.in, 1);
  99        if (isatty(2))
 100                dup2(pager_process.in, 2);
 101        close(pager_process.in);
 102
 103        /* this makes sure that the parent terminates after the pager */
 104        sigchain_push_common(wait_for_pager_signal);
 105        atexit(wait_for_pager);
 106}
 107
 108int pager_in_use(void)
 109{
 110        const char *env;
 111        env = getenv("GIT_PAGER_IN_USE");
 112        return env ? git_config_bool("GIT_PAGER_IN_USE", env) : 0;
 113}
 114
 115/*
 116 * Return cached value (if set) or $COLUMNS environment variable (if
 117 * set and positive) or ioctl(1, TIOCGWINSZ).ws_col (if positive),
 118 * and default to 80 if all else fails.
 119 */
 120int term_columns(void)
 121{
 122        static int term_columns_at_startup;
 123
 124        char *col_string;
 125        int n_cols;
 126
 127        if (term_columns_at_startup)
 128                return term_columns_at_startup;
 129
 130        term_columns_at_startup = 80;
 131
 132        col_string = getenv("COLUMNS");
 133        if (col_string && (n_cols = atoi(col_string)) > 0)
 134                term_columns_at_startup = n_cols;
 135#ifdef TIOCGWINSZ
 136        else {
 137                struct winsize ws;
 138                if (!ioctl(1, TIOCGWINSZ, &ws) && ws.ws_col)
 139                        term_columns_at_startup = ws.ws_col;
 140        }
 141#endif
 142
 143        return term_columns_at_startup;
 144}
 145
 146/*
 147 * How many columns do we need to show this number in decimal?
 148 */
 149int decimal_width(int number)
 150{
 151        int i, width;
 152
 153        for (width = 1, i = 10; i <= number; width++)
 154                i *= 10;
 155        return width;
 156}
 157
 158static int pager_command_config(const char *var, const char *value, void *data)
 159{
 160        struct pager_config *c = data;
 161        if (starts_with(var, "pager.") && !strcmp(var + 6, c->cmd)) {
 162                int b = git_config_maybe_bool(var, value);
 163                if (b >= 0)
 164                        c->want = b;
 165                else {
 166                        c->want = 1;
 167                        c->value = xstrdup(value);
 168                }
 169        }
 170        return 0;
 171}
 172
 173/* returns 0 for "no pager", 1 for "use pager", and -1 for "not specified" */
 174int check_pager_config(const char *cmd)
 175{
 176        struct pager_config c;
 177        c.cmd = cmd;
 178        c.want = -1;
 179        c.value = NULL;
 180        git_config(pager_command_config, &c);
 181        if (c.value)
 182                pager_program = c.value;
 183        return c.want;
 184}