built-in add -i: support `?` (prompt help)

With this change, we print out the same colored help text that the
Perl-based `git add -i` prints in the main loop when question mark is
entered.

Signed-off-by: Johannes Schindelin <johannes.schindelin@gmx.de>
Signed-off-by: Junio C Hamano <gitster@pobox.com>

diff --git a/add-interactive.c b/add-interactive.c
index c5d95d4796441bf083f86999e54a0ace09028609..0a03b9017d4fe0418e24dc25e5a25c632e7beb03 100644 (file)
--- a/add-interactive.c
+++ b/add-interactive.c
@@ -11,6 +11,7 @@ struct add_i_state {
        struct repository *r;
        int use_color;
        char header_color[COLOR_MAXLEN];
+       char help_color[COLOR_MAXLEN];
 };
 
 static void init_color(struct repository *r, struct add_i_state *s,
@@ -43,6 +44,7 @@ static void init_add_i_state(struct add_i_state *s, struct repository *r)
        s->use_color = want_color(s->use_color);
 
        init_color(r, s, "header", s->header_color, GIT_COLOR_BOLD);
+       init_color(r, s, "help", s->help_color, GIT_COLOR_BOLD_RED);
 }
 
 /*
@@ -210,6 +212,7 @@ struct list_and_choose_options {
        struct list_options list_opts;
 
        const char *prompt;
+       void (*print_help)(struct add_i_state *s);
 };
 
 #define LIST_AND_CHOOSE_ERROR (-1)
@@ -250,6 +253,11 @@ static ssize_t list_and_choose(struct add_i_state *s,
                if (!input.len)
                        break;
 
+               if (!strcmp(input.buf, "?")) {
+                       opts->print_help(s);
+                       continue;
+               }
+
                p = input.buf;
                for (;;) {
                        size_t sep = strcspn(p, " \t\r\n,");
@@ -515,12 +523,24 @@ static void print_command_item(int i, struct string_list_item *item,
                       item->string + util->prefix_length);
 }
 
+static void command_prompt_help(struct add_i_state *s)
+{
+       const char *help_color = s->help_color;
+       color_fprintf_ln(stdout, help_color, "%s", _("Prompt help:"));
+       color_fprintf_ln(stdout, help_color, "1          - %s",
+                        _("select a numbered item"));
+       color_fprintf_ln(stdout, help_color, "foo        - %s",
+                        _("select item based on unique prefix"));
+       color_fprintf_ln(stdout, help_color, "           - %s",
+                        _("(empty) select nothing"));
+}
+
 int run_add_i(struct repository *r, const struct pathspec *ps)
 {
        struct add_i_state s = { NULL };
        struct list_and_choose_options main_loop_opts = {
                { 4, N_("*** Commands ***"), print_command_item, NULL },
-               N_("What now")
+               N_("What now"), command_prompt_help
        };
        struct {
                const char *string;