pager.con commit Merge branch 'ak/lazy-prereq-mktemp' into maint (d0366b1)
   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
   9static struct child_process pager_process = CHILD_PROCESS_INIT;
  10static const char *pager_program;
  11
  12static void wait_for_pager(int in_signal)
  13{
  14        if (!in_signal) {
  15                fflush(stdout);
  16                fflush(stderr);
  17        }
  18        /* signal EOF to pager */
  19        close(1);
  20        close(2);
  21        if (in_signal)
  22                finish_command_in_signal(&pager_process);
  23        else
  24                finish_command(&pager_process);
  25}
  26
  27static void wait_for_pager_atexit(void)
  28{
  29        wait_for_pager(0);
  30}
  31
  32static void wait_for_pager_signal(int signo)
  33{
  34        wait_for_pager(1);
  35        sigchain_pop(signo);
  36        raise(signo);
  37}
  38
  39static int core_pager_config(const char *var, const char *value, void *data)
  40{
  41        if (!strcmp(var, "core.pager"))
  42                return git_config_string(&pager_program, var, value);
  43        return 0;
  44}
  45
  46static void read_early_config(config_fn_t cb, void *data)
  47{
  48        git_config_with_options(cb, data, NULL, 1);
  49
  50        /*
  51         * Note that this is a really dirty hack that does the wrong thing in
  52         * many cases. The crux of the problem is that we cannot run
  53         * setup_git_directory() early on in git's setup, so we have no idea if
  54         * we are in a repository or not, and therefore are not sure whether
  55         * and how to read repository-local config.
  56         *
  57         * So if we _aren't_ in a repository (or we are but we would reject its
  58         * core.repositoryformatversion), we'll read whatever is in .git/config
  59         * blindly. Similarly, if we _are_ in a repository, but not at the
  60         * root, we'll fail to find .git/config (because it's really
  61         * ../.git/config, etc). See t7006 for a complete set of failures.
  62         *
  63         * However, we have historically provided this hack because it does
  64         * work some of the time (namely when you are at the top-level of a
  65         * valid repository), and would rarely make things worse (i.e., you do
  66         * not generally have a .git/config file sitting around).
  67         */
  68        if (!startup_info->have_repository) {
  69                struct git_config_source repo_config;
  70
  71                memset(&repo_config, 0, sizeof(repo_config));
  72                repo_config.file = ".git/config";
  73                git_config_with_options(cb, data, &repo_config, 1);
  74        }
  75}
  76
  77const char *git_pager(int stdout_is_tty)
  78{
  79        const char *pager;
  80
  81        if (!stdout_is_tty)
  82                return NULL;
  83
  84        pager = getenv("GIT_PAGER");
  85        if (!pager) {
  86                if (!pager_program)
  87                        read_early_config(core_pager_config, NULL);
  88                pager = pager_program;
  89        }
  90        if (!pager)
  91                pager = getenv("PAGER");
  92        if (!pager)
  93                pager = DEFAULT_PAGER;
  94        if (!*pager || !strcmp(pager, "cat"))
  95                pager = NULL;
  96
  97        return pager;
  98}
  99
 100static void setup_pager_env(struct argv_array *env)
 101{
 102        const char **argv;
 103        int i;
 104        char *pager_env = xstrdup(PAGER_ENV);
 105        int n = split_cmdline(pager_env, &argv);
 106
 107        if (n < 0)
 108                die("malformed build-time PAGER_ENV: %s",
 109                        split_cmdline_strerror(n));
 110
 111        for (i = 0; i < n; i++) {
 112                char *cp = strchr(argv[i], '=');
 113
 114                if (!cp)
 115                        die("malformed build-time PAGER_ENV");
 116
 117                *cp = '\0';
 118                if (!getenv(argv[i])) {
 119                        *cp = '=';
 120                        argv_array_push(env, argv[i]);
 121                }
 122        }
 123        free(pager_env);
 124        free(argv);
 125}
 126
 127void prepare_pager_args(struct child_process *pager_process, const char *pager)
 128{
 129        argv_array_push(&pager_process->args, pager);
 130        pager_process->use_shell = 1;
 131        setup_pager_env(&pager_process->env_array);
 132}
 133
 134void setup_pager(void)
 135{
 136        const char *pager = git_pager(isatty(1));
 137
 138        if (!pager)
 139                return;
 140
 141        /*
 142         * force computing the width of the terminal before we redirect
 143         * the standard output to the pager.
 144         */
 145        (void) term_columns();
 146
 147        setenv("GIT_PAGER_IN_USE", "true", 1);
 148
 149        /* spawn the pager */
 150        prepare_pager_args(&pager_process, pager);
 151        pager_process.in = -1;
 152        argv_array_push(&pager_process.env_array, "GIT_PAGER_IN_USE");
 153        if (start_command(&pager_process))
 154                return;
 155
 156        /* original process continues, but writes to the pipe */
 157        dup2(pager_process.in, 1);
 158        if (isatty(2))
 159                dup2(pager_process.in, 2);
 160        close(pager_process.in);
 161
 162        /* this makes sure that the parent terminates after the pager */
 163        sigchain_push_common(wait_for_pager_signal);
 164        atexit(wait_for_pager_atexit);
 165}
 166
 167int pager_in_use(void)
 168{
 169        const char *env;
 170        env = getenv("GIT_PAGER_IN_USE");
 171        return env ? git_config_bool("GIT_PAGER_IN_USE", env) : 0;
 172}
 173
 174/*
 175 * Return cached value (if set) or $COLUMNS environment variable (if
 176 * set and positive) or ioctl(1, TIOCGWINSZ).ws_col (if positive),
 177 * and default to 80 if all else fails.
 178 */
 179int term_columns(void)
 180{
 181        static int term_columns_at_startup;
 182
 183        char *col_string;
 184        int n_cols;
 185
 186        if (term_columns_at_startup)
 187                return term_columns_at_startup;
 188
 189        term_columns_at_startup = 80;
 190
 191        col_string = getenv("COLUMNS");
 192        if (col_string && (n_cols = atoi(col_string)) > 0)
 193                term_columns_at_startup = n_cols;
 194#ifdef TIOCGWINSZ
 195        else {
 196                struct winsize ws;
 197                if (!ioctl(1, TIOCGWINSZ, &ws) && ws.ws_col)
 198                        term_columns_at_startup = ws.ws_col;
 199        }
 200#endif
 201
 202        return term_columns_at_startup;
 203}
 204
 205/*
 206 * How many columns do we need to show this number in decimal?
 207 */
 208int decimal_width(uintmax_t number)
 209{
 210        int width;
 211
 212        for (width = 1; number >= 10; width++)
 213                number /= 10;
 214        return width;
 215}
 216
 217struct pager_command_config_data {
 218        const char *cmd;
 219        int want;
 220        char *value;
 221};
 222
 223static int pager_command_config(const char *var, const char *value, void *vdata)
 224{
 225        struct pager_command_config_data *data = vdata;
 226        const char *cmd;
 227
 228        if (skip_prefix(var, "pager.", &cmd) && !strcmp(cmd, data->cmd)) {
 229                int b = git_config_maybe_bool(var, value);
 230                if (b >= 0)
 231                        data->want = b;
 232                else {
 233                        data->want = 1;
 234                        data->value = xstrdup(value);
 235                }
 236        }
 237
 238        return 0;
 239}
 240
 241/* returns 0 for "no pager", 1 for "use pager", and -1 for "not specified" */
 242int check_pager_config(const char *cmd)
 243{
 244        struct pager_command_config_data data;
 245
 246        data.cmd = cmd;
 247        data.want = -1;
 248        data.value = NULL;
 249
 250        read_early_config(pager_command_config, &data);
 251
 252        if (data.value)
 253                pager_program = data.value;
 254        return data.want;
 255}