hush: next small step towards functions

diff --git a/shell/hush.c b/shell/hush.c
index 377f13aa4a39a5854f5c834e5a053cbff69dbbe1..6efc3073beecdf7d45c2a2419947882150ca348c 100644 (file)
--- a/shell/hush.c
+++ b/shell/hush.c
@@ -96,6 +96,12 @@
 #endif
 
 
+/* Keep unconditionally on for now */
+#define HUSH_DEBUG 1
+/* In progress... */
+#define ENABLE_HUSH_FUNCTIONS 0
+
+
 /* If you comment out one of these below, it will be #defined later
  * to perform debug printfs to stderr: */
 #define debug_printf(...)        do {} while (0)
@@ -218,8 +224,6 @@ void xxfree(void *ptr)
 #endif
 
 
-/* Keep unconditionally on for now */
-#define HUSH_DEBUG 1
 /* Do we support ANY keywords? */
 #if ENABLE_HUSH_IF || ENABLE_HUSH_LOOPS || ENABLE_HUSH_CASE
 #define HAS_KEYWORDS 1
@@ -307,7 +311,7 @@ struct command {
        pid_t pid;                  /* 0 if exited */
        int assignment_cnt;         /* how many argv[i] are assignments? */
        smallint is_stopped;        /* is the command currently running? */
-       smallint subshell;          /* flag, non-zero if group must be forked */
+       smallint grp_type;
        struct pipe *group;         /* if non-NULL, this "prog" is {} group,
                                     * subshell, or a compound statement */
        char **argv;                /* command name and arguments */
@@ -319,6 +323,11 @@ struct command {
  * Example: argv[0]=='.^C*^C.' here: echo .$*.
  * References of the form ^C`cmd arg^C are `cmd arg` substitutions.
  */
+#define GRP_NORMAL   0
+#define GRP_SUBSHELL 1
+#if ENABLE_HUSH_FUNCTIONS
+#define GRP_FUNCTION 2
+#endif
 
 struct pipe {
        struct pipe *next;
@@ -1016,12 +1025,14 @@ static void o_addstr_duplicate_backslash(o_string *o, const char *str, int len)
 static void o_addqchr(o_string *o, int ch)
 {
        int sz = 1;
-       if (strchr("*?[\\", ch)) {
+       char *found = strchr("*?[\\", ch);
+       if (found)
                sz++;
+       o_grow_by(o, sz);
+       if (found) {
                o->data[o->length] = '\\';
                o->length++;
        }
-       o_grow_by(o, sz);
        o->data[o->length] = ch;
        o->length++;
        o->data[o->length] = '\0';
@@ -1834,7 +1845,15 @@ static int run_pipe(struct pipe *pi)
         */
        command = &(pi->cmds[0]);
 
-       if (single_and_fg && command->group && command->subshell == 0) {
+#if ENABLE_HUSH_FUNCTIONS
+       if (single_and_fg && command->group && command->grp_type == GRP_FUNCTION) {
+               /* We "execute" function definition */
+               bb_error_msg("here we ought to remember function definition, and go on");
+               return EXIT_SUCCESS;
+       }
+#endif
+
+       if (single_and_fg && command->group && command->grp_type == GRP_NORMAL) {
                debug_printf("non-subshell grouping\n");
                setup_redirects(command, squirrel);
                debug_printf_exec(": run_list\n");
@@ -2023,7 +2042,7 @@ static int run_pipe(struct pipe *pi)
 #ifndef debug_print_tree
 static void debug_print_tree(struct pipe *pi, int lvl)
 {
-       static const char *PIPE[] = {
+       static const char *const PIPE[] = {
                [PIPE_SEQ] = "SEQ",
                [PIPE_AND] = "AND",
                [PIPE_OR ] = "OR" ,
@@ -2057,6 +2076,13 @@ static void debug_print_tree(struct pipe *pi, int lvl)
                [RES_XXXX ] = "XXXX" ,
                [RES_SNTX ] = "SNTX" ,
        };
+       static const char *const GRPTYPE[] = {
+               "()",
+               "{}",
+#if ENABLE_HUSH_FUNCTIONS
+               "func()",
+#endif
+       };
 
        int pin, prn;
 
@@ -2072,7 +2098,7 @@ static void debug_print_tree(struct pipe *pi, int lvl)
                        fprintf(stderr, "%*s prog %d assignment_cnt:%d", lvl*2, "", prn, command->assignment_cnt);
                        if (command->group) {
                                fprintf(stderr, " group %s: (argv=%p)\n",
-                                               (command->subshell ? "()" : "{}"),
+                                               GRPTYPE[command->grp_type],
                                                argv);
                                debug_print_tree(command->group, lvl+1);
                                prn++;
@@ -2443,7 +2469,7 @@ static int free_pipe(struct pipe *pi, int indent)
                        free_strings(command->argv);
                        command->argv = NULL;
                } else if (command->group) {
-                       debug_printf_clean("%s   begin group (subshell:%d)\n", indenter(indent), command->subshell);
+                       debug_printf_clean("%s   begin group (grp_type:%d)\n", indenter(indent), command->grp_type);
                        ret_code = free_pipe_list(command->group, indent+3);
                        debug_printf_clean("%s   end group\n", indenter(indent));
                } else {
@@ -2572,7 +2598,6 @@ static int expand_vars_to_list(o_string *output, int n, char *arg, char or_mask)
 #if ENABLE_HUSH_TICK
                o_string subst_result = NULL_O_STRING;
 #endif
-
                o_addstr(output, arg, p - arg);
                debug_print_list("expand_vars_to_list[1]", output, n);
                arg = ++p;
@@ -3100,7 +3125,7 @@ static int reserved_word(o_string *word, struct parse_context *ctx)
                done_pipe(ctx, PIPE_SEQ);
                old = ctx->stack;
                old->command->group = ctx->list_head;
-               old->command->subshell = 0;
+               old->command->grp_type = GRP_NORMAL;
                *ctx = *old;   /* physical copy */
                free(old);
        }
@@ -3461,15 +3486,24 @@ static int process_command_subs(o_string *dest,
 static int parse_group(o_string *dest, struct parse_context *ctx,
        struct in_str *input, int ch)
 {
-       /* NB: parse_group may create and use its own o_string,
-        * without any code changes. It just so happens that code is smaller
-        * if we (ab)use caller's one. */
+       /* dest contains characters seen prior to ( or {.
+        * Typically it's empty, but for functions defs,
+        * it contains function name (without '()'). */
        int rcode;
        const char *endch = NULL;
        struct parse_context sub;
        struct command *command = ctx->command;
 
        debug_printf_parse("parse_group entered\n");
+#if ENABLE_HUSH_FUNCTIONS
+       if (ch == 'F') { /* function definition? */
+               bb_error_msg("aha '%s' is a function, parsing it...", dest->data);
+               //command->fname = dest->data;
+               command->grp_type = GRP_FUNCTION;
+//TODO: review every o_reset() location... do they handle all o_string fields correctly?
+               memset(dest, 0, sizeof(*dest));
+       }
+#endif
        if (command->argv /* word [word](... */
         || dest->length /* word(... */
         || dest->nonnull /* ""(... */
@@ -3482,11 +3516,8 @@ static int parse_group(o_string *dest, struct parse_context *ctx,
        endch = "}";
        if (ch == '(') {
                endch = ")";
-               command->subshell = 1;
+               command->grp_type = GRP_SUBSHELL;
        }
-//TODO if (ch == 'F') { /* function definition */
-//             command->subshell = 2;
-//     }
        rcode = parse_stream(dest, &sub, input, endch);
        if (rcode == 0) {
                done_word(dest, &sub); /* finish off the final word in the subcontext */
@@ -3988,16 +4019,18 @@ static int parse_stream(o_string *dest, struct parse_context *ctx,
                                continue;
                        }
 #endif
-#if 0 /* TODO: implement functions */
+#if ENABLE_HUSH_FUNCTIONS
                        if (dest->length != 0 /* not just () but word() */
                         && dest->nonnull == 0 /* not a"b"c() */
                         && ctx->command->argv == NULL /* it's the first word */
+//TODO: "func ( ) {...}" - note spaces - is valid format too in bash
                         && i_peek(input) == ')'
                         && !match_reserved_word(dest)
                        ) {
                                bb_error_msg("seems like a function definition");
                                i_getch(input);
                                do {
+//TODO: do it properly.
                                        ch = i_getch(input);
                                } while (ch == ' ' || ch == '\n');
                                if (ch != '{') {
@@ -4005,6 +4038,7 @@ static int parse_stream(o_string *dest, struct parse_context *ctx,
                                        debug_printf_parse("parse_stream return 1\n");
                                        return 1;
                                }
+                               ch = 'F'; /* magic value */
                        }
 #endif
                case '{':