ash,hush: allow builtins to be tab-completed, closes 7532

function                                             old     new   delta
complete_cmd_dir_file                                678     830    +152
get_builtin_name                                       -      35     +35
optschanged                                          125     132      +7
hush_main                                           1069    1076      +7
save_command_ps_at_cur_history                        76      78      +2
------------------------------------------------------------------------------
(add/remove: 1/0 grow/shrink: 4/0 up/down: 203/0)             Total: 203 bytes

Signed-off-by: Ron Yorston <rmy@pobox.com>
Signed-off-by: Denys Vlasenko <vda.linux@googlemail.com>

4 files changed, 62 insertions, 4 deletions

diff --git a/include/libbb.h b/include/libbb.h
index 05a560977..392c0443d 100644
--- a/include/libbb.h
+++ b/include/libbb.h
@@ -1818,10 +1818,19 @@ unsigned size_from_HISTFILESIZE(const char *hp) FAST_FUNC;
 # else
 #  define MAX_HISTORY 0
 # endif
+typedef const char *get_exe_name_t(int i) FAST_FUNC;
 typedef struct line_input_t {
         int flags;
         int timeout;
         const char *path_lookup;
+# if ENABLE_FEATURE_TAB_COMPLETION \
+&& (ENABLE_ASH  || ENABLE_SH_IS_ASH  || ENABLE_BASH_IS_ASH \
+||  ENABLE_HUSH || ENABLE_SH_IS_HUSH || ENABLE_BASH_IS_HUSH \
+)
+        /* function to fetch additional application-specific names to match */
+        get_exe_name_t *get_exe_name;
+#  define EDITING_HAS_get_exe_name 1
+# endif
 # if MAX_HISTORY
         int cnt_history;
         int cur_history;
@@ -1868,6 +1877,10 @@ int read_line_input(const char* prompt, char* command, int maxsize) FAST_FUNC;
         read_line_input(prompt, command, maxsize)
 #endif
 
+#ifndef EDITING_HAS_get_exe_name
+# define EDITING_HAS_get_exe_name 0
+#endif
+
 
 #ifndef COMM_LEN
 # ifdef TASK_COMM_LEN
diff --git a/libbb/lineedit.c b/libbb/lineedit.c
index b1ec52b88..de236dea0 100644
--- a/libbb/lineedit.c
+++ b/libbb/lineedit.c
@@ -813,18 +813,29 @@ static NOINLINE unsigned complete_cmd_dir_file(const char *command, int type)
         }
         pf_len = strlen(pfind);
 
-# if ENABLE_FEATURE_SH_STANDALONE && NUM_APPLETS != 1
         if (type == FIND_EXE_ONLY && !dirbuf) {
+# if ENABLE_FEATURE_SH_STANDALONE && NUM_APPLETS != 1
                 const char *p = applet_names;
-
                 while (*p) {
                         if (strncmp(pfind, p, pf_len) == 0)
                                 add_match(xstrdup(p));
                         while (*p++ != '\0')
                                 continue;
                 }
-        }
 # endif
+# if EDITING_HAS_get_exe_name
+                if (state->get_exe_name) {
+                        i = 0;
+                        for (;;) {
+                                const char *b = state->get_exe_name(i++);
+                                if (!b)
+                                        break;
+                                if (strncmp(pfind, b, pf_len) == 0)
+                                        add_match(xstrdup(b));
+                        }
+                }
+# endif
+        }
 
         for (i = 0; i < npaths; i++) {
                 DIR *dir;
diff --git a/shell/ash.c b/shell/ash.c
index d6040f47e..fb4028219 100644
--- a/shell/ash.c
+++ b/shell/ash.c
@@ -9523,6 +9523,11 @@ evalpipe(union node *n, int flags)
         return status;
 }
 
+/* setinteractive needs this forward reference */
+#if EDITING_HAS_get_exe_name
+static const char *get_builtin_name(int i) FAST_FUNC;
+#endif
+
 /*
  * Controls whether the shell is interactive or not.
  */
@@ -9554,8 +9559,12 @@ setinteractive(int on)
                 }
 #endif
 #if ENABLE_FEATURE_EDITING
-                if (!line_input_state)
+                if (!line_input_state) {
                         line_input_state = new_line_input_t(FOR_SHELL | WITH_PATH_LOOKUP);
+# if EDITING_HAS_get_exe_name
+                        line_input_state->get_exe_name = get_builtin_name;
+# endif
+                }
 #endif
         }
 }
@@ -10023,6 +10032,14 @@ find_builtin(const char *name)
         return bp;
 }
 
+#if EDITING_HAS_get_exe_name
+static const char * FAST_FUNC
+get_builtin_name(int i)
+{
+        return /*i >= 0 &&*/ i < ARRAY_SIZE(builtintab) ? builtintab[i].name + 1 : NULL;
+}
+#endif
+
 /*
  * Execute a simple command.
  */
diff --git a/shell/hush.c b/shell/hush.c
index 97202b953..6e44d4e11 100644
--- a/shell/hush.c
+++ b/shell/hush.c
@@ -7889,6 +7889,20 @@ static const struct built_in_command *find_builtin(const char *name)
         return find_builtin_helper(name, bltins2, &bltins2[ARRAY_SIZE(bltins2)]);
 }
 
+#if EDITING_HAS_get_exe_name
+static const char * FAST_FUNC get_builtin_name(int i)
+{
+        if (/*i >= 0 && */ i < ARRAY_SIZE(bltins1)) {
+                return bltins1[i].b_cmd;
+        }
+        i -= ARRAY_SIZE(bltins1);
+        if (i < ARRAY_SIZE(bltins2)) {
+                return bltins2[i].b_cmd;
+        }
+        return NULL;
+}
+#endif
+
 static void remove_nested_vars(void)
 {
         struct variable *cur;
@@ -10268,6 +10282,9 @@ int hush_main(int argc, char **argv)
 
 # if ENABLE_FEATURE_EDITING
                 G.line_input_state = new_line_input_t(FOR_SHELL);
+#  if EDITING_HAS_get_exe_name
+                G.line_input_state->get_exe_name = get_builtin_name;
+#  endif
 # endif
 # if ENABLE_HUSH_SAVEHISTORY && MAX_HISTORY > 0
                 {