diff options
Diffstat (limited to 'pager.c')
| -rw-r--r-- | pager.c | 266 |
1 files changed, 266 insertions, 0 deletions
@@ -0,0 +1,266 @@ +#include "git-compat-util.h" +#include "config.h" +#include "editor.h" +#include "pager.h" +#include "run-command.h" +#include "sigchain.h" +#include "alias.h" + +int pager_use_color = 1; + +#ifndef DEFAULT_PAGER +#define DEFAULT_PAGER "less" +#endif + +static struct child_process pager_process; +static const char *pager_program; + +/* Is the value coming back from term_columns() just a guess? */ +static int term_columns_guessed; + + +static void close_pager_fds(void) +{ + /* signal EOF to pager */ + close(1); + close(2); +} + +static void wait_for_pager_atexit(void) +{ + fflush(stdout); + fflush(stderr); + close_pager_fds(); + finish_command(&pager_process); +} + +static void wait_for_pager_signal(int signo) +{ + close_pager_fds(); + finish_command_in_signal(&pager_process); + sigchain_pop(signo); + raise(signo); +} + +static int core_pager_config(const char *var, const char *value, + const struct config_context *ctx UNUSED, + void *data UNUSED) +{ + if (!strcmp(var, "core.pager")) + return git_config_string(&pager_program, var, value); + return 0; +} + +const char *git_pager(int stdout_is_tty) +{ + const char *pager; + + if (!stdout_is_tty) + return NULL; + + pager = getenv("GIT_PAGER"); + if (!pager) { + if (!pager_program) + read_early_config(core_pager_config, NULL); + pager = pager_program; + } + if (!pager) + pager = getenv("PAGER"); + if (!pager) + pager = DEFAULT_PAGER; + if (!*pager || !strcmp(pager, "cat")) + pager = NULL; + + return pager; +} + +static void setup_pager_env(struct strvec *env) +{ + const char **argv; + int i; + char *pager_env = xstrdup(PAGER_ENV); + int n = split_cmdline(pager_env, &argv); + + if (n < 0) + die("malformed build-time PAGER_ENV: %s", + split_cmdline_strerror(n)); + + for (i = 0; i < n; i++) { + char *cp = strchr(argv[i], '='); + + if (!cp) + die("malformed build-time PAGER_ENV"); + + *cp = '\0'; + if (!getenv(argv[i])) { + *cp = '='; + strvec_push(env, argv[i]); + } + } + free(pager_env); + free(argv); +} + +void prepare_pager_args(struct child_process *pager_process, const char *pager) +{ + strvec_push(&pager_process->args, pager); + pager_process->use_shell = 1; + setup_pager_env(&pager_process->env); + pager_process->trace2_child_class = "pager"; +} + +void setup_pager(void) +{ + const char *pager = git_pager(isatty(1)); + + if (!pager) + return; + + /* + * After we redirect standard output, we won't be able to use an ioctl + * to get the terminal size. Let's grab it now, and then set $COLUMNS + * to communicate it to any sub-processes. + */ + { + char buf[64]; + xsnprintf(buf, sizeof(buf), "%d", term_columns()); + if (!term_columns_guessed) + setenv("COLUMNS", buf, 0); + } + + setenv("GIT_PAGER_IN_USE", "true", 1); + + child_process_init(&pager_process); + + /* spawn the pager */ + prepare_pager_args(&pager_process, pager); + pager_process.in = -1; + strvec_push(&pager_process.env, "GIT_PAGER_IN_USE"); + if (start_command(&pager_process)) + return; + + /* original process continues, but writes to the pipe */ + dup2(pager_process.in, 1); + if (isatty(2)) + dup2(pager_process.in, 2); + close(pager_process.in); + + /* this makes sure that the parent terminates after the pager */ + sigchain_push_common(wait_for_pager_signal); + atexit(wait_for_pager_atexit); +} + +int pager_in_use(void) +{ + return git_env_bool("GIT_PAGER_IN_USE", 0); +} + +/* + * Return cached value (if set) or $COLUMNS environment variable (if + * set and positive) or ioctl(1, TIOCGWINSZ).ws_col (if positive), + * and default to 80 if all else fails. + */ +int term_columns(void) +{ + static int term_columns_at_startup; + + char *col_string; + int n_cols; + + if (term_columns_at_startup) + return term_columns_at_startup; + + term_columns_at_startup = 80; + term_columns_guessed = 1; + + col_string = getenv("COLUMNS"); + if (col_string && (n_cols = atoi(col_string)) > 0) { + term_columns_at_startup = n_cols; + term_columns_guessed = 0; + } +#ifdef TIOCGWINSZ + else { + struct winsize ws; + if (!ioctl(1, TIOCGWINSZ, &ws) && ws.ws_col) { + term_columns_at_startup = ws.ws_col; + term_columns_guessed = 0; + } + } +#endif + + return term_columns_at_startup; +} + +/* + * Clear the entire line, leave cursor in first column. + */ +void term_clear_line(void) +{ + if (is_terminal_dumb()) + /* + * Fall back to print a terminal width worth of space + * characters (hoping that the terminal is still as wide + * as it was upon the first call to term_columns()). + */ + fprintf(stderr, "\r%*s\r", term_columns(), ""); + else + /* + * On non-dumb terminals use an escape sequence to clear + * the whole line, no matter how wide the terminal. + */ + fputs("\r\033[K", stderr); +} + +/* + * How many columns do we need to show this number in decimal? + */ +int decimal_width(uintmax_t number) +{ + int width; + + for (width = 1; number >= 10; width++) + number /= 10; + return width; +} + +struct pager_command_config_data { + const char *cmd; + int want; + char *value; +}; + +static int pager_command_config(const char *var, const char *value, + const struct config_context *ctx UNUSED, + void *vdata) +{ + struct pager_command_config_data *data = vdata; + const char *cmd; + + if (skip_prefix(var, "pager.", &cmd) && !strcmp(cmd, data->cmd)) { + int b = git_parse_maybe_bool(value); + if (b >= 0) + data->want = b; + else { + data->want = 1; + data->value = xstrdup(value); + } + } + + return 0; +} + +/* returns 0 for "no pager", 1 for "use pager", and -1 for "not specified" */ +int check_pager_config(const char *cmd) +{ + struct pager_command_config_data data; + + data.cmd = cmd; + data.want = -1; + data.value = NULL; + + read_early_config(pager_command_config, &data); + + if (data.value) + pager_program = data.value; + return data.want; +} |