[PATCH v3 09/11] built-in add -i: support `?` (prompt help)

[Johannes Schindelin via GitGitGadget]

From: Johannes Schindelin <johannes.schinde...@gmx.de>

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.schinde...@gmx.de>
---
 add-interactive.c | 22 +++++++++++++++++++++-
 1 file changed, 21 insertions(+), 1 deletion(-)

diff --git a/add-interactive.c b/add-interactive.c
index 7ff87bae1b..1435c12be9 100644
--- 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 int init_add_i_state(struct repository *r, struct 
add_i_state *s)
        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);
 
        return 0;
 }
@@ -104,6 +106,7 @@ 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)
@@ -144,6 +147,11 @@ static ssize_t list_and_choose(struct prefix_item **items, 
size_t nr,
                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,");
@@ -430,12 +438,24 @@ struct command_item {
                       struct file_list *files, struct list_options *opts);
 };
 
+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 command_item
                status = { { "status" }, run_status };
-- 
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