help: use "man.<tool>.cmd" as custom man viewer command

Currently "git help -m GITCMD" is restricted to a set of man viewers
defined at compile time. You can subvert the "man.<tool>.path" to
force "git help -m" to use a different man, viewer, but if you have a
man viewer whose invocation syntax does not match one of the current
tools then you would have to write a wrapper script for it.

This patch adds a git config variable "man.<tool>.cmd" which allows a
more flexible man viewer choice.

If you run "git help -m GITCMD" with the "man.viewer" config variable
set to an unrecognized tool then it will query the "man.<tool>.cmd"
config variable. If this variable exists, then the specified tool will
be treated as a custom man viewer and it will be run in a shell with
the man page name of the GITCMD added as extra parameter.

Signed-off-by: Christian Couder <chriscool@tuxfamily.org>
Signed-off-by: Junio C Hamano <gitster@pobox.com>

diff --git a/help.c b/help.c
index 483e1e9c3824a39d231fca353c2fd68f1a68f840..af80979fcb177faace150a7cfa7cb66daeb59f49 100644 (file)
--- a/help.c
+++ b/help.c
@@ -163,7 +163,15 @@ static void exec_man_man(const char* path, const char *page)
        warning("failed to exec '%s': %s", path, strerror(errno));
 }
 
-static void do_add_man_viewer(const char *name)
+static void exec_man_cmd(const char *cmd, const char *page)
+{
+       struct strbuf shell_cmd = STRBUF_INIT;
+       strbuf_addf(&shell_cmd, "%s %s", cmd, page);
+       execl("/bin/sh", "sh", "-c", shell_cmd.buf, NULL);
+       warning("failed to exec '%s': %s", cmd, strerror(errno));
+}
+
+static void add_man_viewer(const char *name)
 {
        struct man_viewer_list **p = &man_viewer_list;
        size_t len = strlen(name);
@@ -181,16 +189,6 @@ static int supported_man_viewer(const char *name, size_t len)
                !strncasecmp("konqueror", name, len));
 }
 
-static int add_man_viewer(const char *value)
-{
-       if (supported_man_viewer(value, strlen(value)))
-               do_add_man_viewer(value);
-       else
-               warning("'%s': unsupported man viewer.", value);
-
-       return 0;
-}
-
 static void do_add_man_viewer_info(const char *name,
                                   size_t len,
                                   const char *value)
@@ -210,7 +208,23 @@ static int add_man_viewer_path(const char *name,
        if (supported_man_viewer(name, len))
                do_add_man_viewer_info(name, len, value);
        else
-               warning("'%s': path for unsupported man viewer.", name);
+               warning("'%s': path for unsupported man viewer.\n"
+                       "Please consider using 'man.<tool>.cmd' instead.",
+                       name);
+
+       return 0;
+}
+
+static int add_man_viewer_cmd(const char *name,
+                             size_t len,
+                             const char *value)
+{
+       if (supported_man_viewer(name, len))
+               warning("'%s': cmd for supported man viewer.\n"
+                       "Please consider using 'man.<tool>.path' instead.",
+                       name);
+       else
+               do_add_man_viewer_info(name, len, value);
 
        return 0;
 }
@@ -228,6 +242,11 @@ static int add_man_viewer_info(const char *var, const char *value)
                        return config_error_nonbool(var);
                return add_man_viewer_path(name, subkey - name, value);
        }
+       if (!strcmp(subkey, ".cmd")) {
+               if (!value)
+                       return config_error_nonbool(var);
+               return add_man_viewer_cmd(name, subkey - name, value);
+       }
 
        warning("'%s': unsupported man viewer sub key.", subkey);
        return 0;
@@ -244,7 +263,8 @@ static int git_help_config(const char *var, const char *value)
        if (!strcmp(var, "man.viewer")) {
                if (!value)
                        return config_error_nonbool(var);
-               return add_man_viewer(value);
+               add_man_viewer(value);
+               return 0;
        }
        if (!prefixcmp(var, "man."))
                return add_man_viewer_info(var, value);
@@ -546,16 +566,18 @@ static void setup_man_path(void)
 
 static void exec_viewer(const char *name, const char *page)
 {
-       const char *path = get_man_viewer_info(name);
+       const char *info = get_man_viewer_info(name);
 
        if (!strcasecmp(name, "man"))
-               exec_man_man(path, page);
+               exec_man_man(info, page);
        else if (!strcasecmp(name, "woman"))
-               exec_woman_emacs(path, page);
+               exec_woman_emacs(info, page);
        else if (!strcasecmp(name, "konqueror"))
-               exec_man_konqueror(path, page);
+               exec_man_konqueror(info, page);
+       else if (info)
+               exec_man_cmd(info, page);
        else
-               warning("'%s': unsupported man viewer.", name);
+               warning("'%s': unknown man viewer.", name);
 }
 
 static void show_man_page(const char *git_cmd)