Merge branch 'cb/maint-orphan-merge-noclobber'
[git/kirr.git] / pager.c
blobdac358f047550a07dd8d90b2e410feab3eebd534
1 #include "cache.h"
2 #include "run-command.h"
3 #include "sigchain.h"
5 #ifndef DEFAULT_PAGER
6 #define DEFAULT_PAGER "less"
7 #endif
9 /*
10 * This is split up from the rest of git so that we can do
11 * something different on Windows.
14 static int spawned_pager;
16 #ifndef WIN32
17 static void pager_preexec(void)
20 * Work around bug in "less" by not starting it until we
21 * have real input
23 fd_set in;
25 FD_ZERO(&in);
26 FD_SET(0, &in);
27 select(1, &in, NULL, &in, NULL);
29 #endif
31 static const char *pager_argv[] = { NULL, NULL };
32 static struct child_process pager_process;
34 static void wait_for_pager(void)
36 fflush(stdout);
37 fflush(stderr);
38 /* signal EOF to pager */
39 close(1);
40 close(2);
41 finish_command(&pager_process);
44 static void wait_for_pager_signal(int signo)
46 wait_for_pager();
47 sigchain_pop(signo);
48 raise(signo);
51 const char *git_pager(int stdout_is_tty)
53 const char *pager;
55 if (!stdout_is_tty)
56 return NULL;
58 pager = getenv("GIT_PAGER");
59 if (!pager) {
60 if (!pager_program)
61 git_config(git_default_config, NULL);
62 pager = pager_program;
64 if (!pager)
65 pager = getenv("PAGER");
66 if (!pager)
67 pager = DEFAULT_PAGER;
68 else if (!*pager || !strcmp(pager, "cat"))
69 pager = NULL;
71 return pager;
74 void setup_pager(void)
76 const char *pager = git_pager(isatty(1));
78 if (!pager)
79 return;
81 spawned_pager = 1; /* means we are emitting to terminal */
83 /* spawn the pager */
84 pager_argv[0] = pager;
85 pager_process.use_shell = 1;
86 pager_process.argv = pager_argv;
87 pager_process.in = -1;
88 if (!getenv("LESS")) {
89 static const char *env[] = { "LESS=FRSX", NULL };
90 pager_process.env = env;
92 #ifndef WIN32
93 pager_process.preexec_cb = pager_preexec;
94 #endif
95 if (start_command(&pager_process))
96 return;
98 /* original process continues, but writes to the pipe */
99 dup2(pager_process.in, 1);
100 if (isatty(2))
101 dup2(pager_process.in, 2);
102 close(pager_process.in);
104 /* this makes sure that the parent terminates after the pager */
105 sigchain_push_common(wait_for_pager_signal);
106 atexit(wait_for_pager);
109 int pager_in_use(void)
111 const char *env;
113 if (spawned_pager)
114 return 1;
116 env = getenv("GIT_PAGER_IN_USE");
117 return env ? git_config_bool("GIT_PAGER_IN_USE", env) : 0;