branch master updated: Check for man page with 'man -w'

[Gavin D. Smith]

This is an automated email from the git hooks/post-receive script.

gavin pushed a commit to branch master
in repository texinfo.

The following commit(s) were added to refs/heads/master by this push:
     new 8520d2b4d8 Check for man page with 'man -w'
8520d2b4d8 is described below

commit 8520d2b4d80eebe49ed44f11c47901f87d35c29f
Author: Gavin Smith <gavinsmith0123@gmail.com>
AuthorDate: Sun Oct 16 14:21:32 2022 +0100

    Check for man page with 'man -w'
    
    * info/man.c (check_manpage_node): New function, to check if
    man page exists with 'man -w'.  This is much faster for large
    man pages.
    (find_man_formatter): Cache return value.
    * info/info.c (get_initial_file): Use check_manpage_node instead
    of get_manpage_node.
    
    'info -w ffmpeg-all' was reported to be slow by Hilmar Preusse.
    'ffmpeg-all' is an especially long man page, so takes a longer time
    for nroff to format.
---
 ChangeLog   | 15 ++++++++++++++
 info/info.c |  7 +++----
 info/man.c  | 66 ++++++++++++++++++++++++++++++++++++++++++++++++++++++++++---
 info/man.h  |  1 +
 4 files changed, 82 insertions(+), 7 deletions(-)

diff --git a/ChangeLog b/ChangeLog
index 18079094d8..6591ca269b 100644
--- a/ChangeLog
+++ b/ChangeLog
@@ -1,3 +1,18 @@
+2022-10-16  Gavin Smith  <gavinsmith0123@gmail.com>
+
+       Check for man page with 'man -w'
+
+       * info/man.c (check_manpage_node): New function, to check if
+       man page exists with 'man -w'.  This is much faster for large
+       man pages.
+       (find_man_formatter): Cache return value.
+       * info/info.c (get_initial_file): Use check_manpage_node instead
+       of get_manpage_node.
+
+       'info -w ffmpeg-all' was reported to be slow by Hilmar Preusse.
+       'ffmpeg-all' is an especially long man page, so takes a longer time
+       for nroff to format.
+
 2022-10-16  Gavin Smith  <gavinsmith0123@gmail.com>
 
        * info/info.c (main) <--output>: Exit with status of 1, not 0,
diff --git a/info/info.c b/info/info.c
index 23f849d46e..989be3676a 100644
--- a/info/info.c
+++ b/info/info.c
@@ -281,19 +281,18 @@ get_initial_file (int *argc, char ***argv, char **error)
 
   /* Fall back to loading man page. */
     {
-      NODE *man_node;
+      int man_exists;
 
       debug (3, ("falling back to manpage node"));
 
-      man_node = get_manpage_node ((*argv)[0]);
-      if (man_node)
+      man_exists = check_manpage_node ((*argv)[0]);
+      if (man_exists)
         {
           add_pointer_to_array
             (info_new_reference (MANPAGE_FILE_BUFFER_NAME, (*argv)[0]),
              ref_index, ref_list, ref_slots, 2);
 
           initial_file = MANPAGE_FILE_BUFFER_NAME;
-          free (man_node);
           return;
         }
     }
diff --git a/info/man.c b/info/man.c
index 32019d4695..351cd3e972 100644
--- a/info/man.c
+++ b/info/man.c
@@ -56,12 +56,64 @@ static char const * const exec_extensions[] = { "", NULL };
 static REFERENCE **xrefs_of_manpage (NODE *node);
 static char *read_from_fd (int fd);
 static char *get_manpage_contents (char *pagename);
+static char *find_man_formatter (void);
 
 /* We store the contents of retrieved man pages in here. */
 static NODE **manpage_nodes = 0;
 size_t manpage_node_index = 0;
 size_t manpage_node_slots = 0;
 
+#if PIPE_USE_FORK
+
+/* Check if a man page exists.  Use "man -w" for this rather than getting
+   the contents of the man page.  This is faster if we are running
+   "info --where" and we don't need the contents. */
+int
+check_manpage_node (char *pagename)
+{
+  char *cmd;
+  pid_t child;
+  int pid_status;
+
+  child = fork ();
+  if (child == -1)
+    return 0; /* couldn't fork */
+
+  if (!child)
+    {
+      int ret;
+      freopen (NULL_DEVICE, "w", stdout);
+      freopen (NULL_DEVICE, "w", stderr);
+      char *formatter = find_man_formatter();
+      if (!formatter)
+        exit (1);
+      ret = execl (formatter, formatter, "-w", pagename, (void *) 0);
+      exit (1); /* exec failed */
+    }
+  else
+    {
+      wait (&pid_status);
+    }
+
+  return !pid_status;
+}
+
+#else /* !PIPE_USE_FORK */
+
+int
+check_manpage_node (char *pagename)
+{
+  NODE *man_node = get_manpage_node (pagename);
+  if (man_node)
+    {
+      free (man_node);
+      return 1;
+    }
+  return 0;
+}
+
+#endif /* !PIPE_USE_FORK */
+
 NODE *
 get_manpage_node (char *pagename)
 {
@@ -170,9 +222,17 @@ executable_file_in_path (char *filename, char *path)
 static char *
 find_man_formatter (void)
 {
-  char *man_command = getenv ("INFO_MAN_COMMAND");
-  return man_command ? man_command :
-                       executable_file_in_path ("man", getenv ("PATH"));
+  static char *man_formatter;
+  char *man_command;
+
+  if (man_formatter)
+    return man_formatter;
+
+  man_command = getenv ("INFO_MAN_COMMAND");
+  man_formatter = man_command ? man_command
+                    : executable_file_in_path ("man", getenv ("PATH"));
+
+  return man_formatter;
 }
 
 static char *manpage_pagename = NULL;
diff --git a/info/man.h b/info/man.h
index 536e41a397..034c2e77aa 100644
--- a/info/man.h
+++ b/info/man.h
@@ -22,6 +22,7 @@
 
 #define MANPAGE_FILE_BUFFER_NAME "*manpages*"
 
+int check_manpage_node (char *pagename);
 extern NODE *get_manpage_node (char *pagename);
 
 #endif /* INFO_MAN_H */