pager.c

   1 #include "cache.h"
   2 #include "run-command.h"
   3
   4 /*
   5  * This is split up from the rest of git so that we can do
   6  * something different on Windows.
   7  */
   8
   9 static int spawned_pager;
  10
  11 #ifndef __MINGW32__
  12 static void pager_preexec(void)
  13 {
  14         /*
  15          * Work around bug in "less" by not starting it until we
  16          * have real input
  17          */
  18         fd_set in;
  19
  20         FD_ZERO(&in);
  21         FD_SET(0, &in);
  22         select(1, &in, NULL, &in, NULL);
  23
  24         setenv("LESS", "FRSX", 0);
  25 }
  26 #endif
  27
  28 static const char *pager_argv[] = { "sh", "-c", NULL, NULL };
  29 static struct child_process pager_process;
  30
  31 static void wait_for_pager(void)
  32 {
  33         fflush(stdout);
  34         fflush(stderr);
  35         /* signal EOF to pager */
  36         close(1);
  37         close(2);
  38         finish_command(&pager_process);
  39 }
  40
  41 void setup_pager(void)
  42 {
  43         const char *pager = getenv("GIT_PAGER");
  44
  45         if (!isatty(1))
  46                 return;
  47         if (!pager) {
  48                 if (!pager_program)
  49                         git_config(git_default_config, NULL);
  50                 pager = pager_program;
  51         }
  52         if (!pager)
  53                 pager = getenv("PAGER");
  54         if (!pager)
  55                 pager = "less";
  56         else if (!*pager || !strcmp(pager, "cat"))
  57                 return;
  58
  59         spawned_pager = 1; /* means we are emitting to terminal */
  60
  61         /* spawn the pager */
  62         pager_argv[2] = pager;
  63         pager_process.argv = pager_argv;
  64         pager_process.in = -1;
  65 #ifndef __MINGW32__
  66         pager_process.preexec_cb = pager_preexec;
  67 #endif
  68         if (start_command(&pager_process))
  69                 return;
  70
  71         /* original process continues, but writes to the pipe */
  72         dup2(pager_process.in, 1);
  73         if (isatty(2))
  74                 dup2(pager_process.in, 2);
  75         close(pager_process.in);
  76
  77         /* this makes sure that the parent terminates after the pager */
  78         atexit(wait_for_pager);
  79 }
  80
  81 int pager_in_use(void)
  82 {
  83         const char *env;
  84
  85         if (spawned_pager)
  86                 return 1;
  87
  88         env = getenv("GIT_PAGER_IN_USE");
  89         return env ? git_config_bool("GIT_PAGER_IN_USE", env) : 0;
  90 }