hush: straighten parse_stream() API a bit

function                                             old     new   delta
parse_stream                                        1240    1238      -2
expand_variables                                    2272    2242     -30
parse_and_run_stream                                 338     292     -46
------------------------------------------------------------------------------
(add/remove: 0/0 grow/shrink: 0/3 up/down: 0/-78)             Total: -78 bytes

1 files changed, 24 insertions, 19 deletions

diff --git a/shell/hush.c b/shell/hush.c
index f0d372625..eeec13b3d 100644
--- a/shell/hush.c
+++ b/shell/hush.c
@@ -3765,14 +3765,10 @@ static int process_command_subs(o_string *dest,
         FILE *p;
         struct in_str pipe_str;
 
-        initialize_context(&inner);
-
         /* Recursion to generate command */
         retcode = parse_stream(&result, &inner, input, subst_end);
         if (retcode != 0)
                 return retcode;  /* syntax error or EOF */
-        done_word(&result, &inner);
-        done_pipe(&inner, PIPE_SEQ);
         o_free(&result);
 
         p = generate_stream_from_list(inner.list_head);
@@ -3812,10 +3808,10 @@ static int parse_group(o_string *dest, struct parse_context *ctx,
         struct in_str *input, int ch)
 {
         /* dest contains characters seen prior to ( or {.
-         * Typically it's empty, but for functions defs,
+         * Typically it's empty, but for function defs,
          * it contains function name (without '()'). */
         int rcode;
-        const char *endch = NULL;
+        const char *endch;
         struct parse_context sub;
         struct command *command = ctx->command;
 
@@ -3837,7 +3833,6 @@ static int parse_group(o_string *dest, struct parse_context *ctx,
                 debug_printf_parse("parse_group return 1: syntax error, groups and arglists don't mix\n");
                 return 1;
         }
-        initialize_context(&sub);
         endch = "}";
         if (ch == '(') {
                 endch = ")";
@@ -3845,8 +3840,6 @@ static int parse_group(o_string *dest, struct parse_context *ctx,
         }
         rcode = parse_stream(dest, &sub, input, endch);
         if (rcode == 0) {
-                done_word(dest, &sub); /* finish off the final word in the subcontext */
-                done_pipe(&sub, PIPE_SEQ);  /* and the final command there, too */
                 command->group = sub.list_head;
         }
         debug_printf_parse("parse_group return %d\n", rcode);
@@ -4211,11 +4204,14 @@ static int parse_stream_dquoted(o_string *dest, struct in_str *input, int dquote
         goto again;
 }
 
-/* Scan input, call done_word() whenever full IFS delimited word was seen.
+/* Initalize ctx (i.e. caller does not need to do that).
+ * Scan input, call done_word() whenever full IFS delimited word was seen.
  * Call done_pipe if '\n' was seen (and end_trigger != NULL).
  * Return code is 0 if end_trigger char is met,
  * -1 on EOF (but if end_trigger == NULL then return 0),
- * 1 for syntax error */
+ * 1 for syntax error
+ * Net result is a list of pipes in ctx->list_head.
+ */
 static int parse_stream(o_string *dest, struct parse_context *ctx,
                 struct in_str *input, const char *end_trigger)
 {
@@ -4230,6 +4226,7 @@ static int parse_stream(o_string *dest, struct parse_context *ctx,
          * found.  When recursing, quote state is passed in via dest->o_escape. */
 
         debug_printf_parse("parse_stream entered, end_trigger='%s' dest->o_assignment:%d\n", end_trigger, dest->o_assignment);
+        initialize_context(ctx);
 
         is_in_dquote = dest->o_escape;
         while (1) {
@@ -4269,7 +4266,7 @@ static int parse_stream(o_string *dest, struct parse_context *ctx,
                                 return 1;
                         }
                         if (ch == EOF)
-                                break;
+                                goto ret_EOF;
                         /* If we aren't performing a substitution, treat
                          * a newline as a command separator.
                          * [why don't we handle it exactly like ';'? --vda] */
@@ -4297,11 +4294,14 @@ static int parse_stream(o_string *dest, struct parse_context *ctx,
                                         done_pipe(ctx, PIPE_SEQ);
                                         dest->o_assignment = MAYBE_ASSIGNMENT;
                                 }
+                                /* What do we check here? */
                                 if (!HAS_KEYWORDS
                                  IF_HAS_KEYWORDS(|| (ctx->ctx_res_w == RES_NONE && ctx->old_flag == 0))
                                 ) {
                                         debug_printf_parse("parse_stream return 0: end_trigger char found\n");
-                                        return 0;
+                                        /* this makes us return 0, not -1 */
+                                        end_trigger = NULL;
+                                        goto ret;
                                 }
                         }
                 }
@@ -4522,9 +4522,16 @@ static int parse_stream(o_string *dest, struct parse_context *ctx,
                                 bb_error_msg_and_die("BUG: unexpected %c\n", ch);
                 }
         } /* while (1) */
+
+        /* Non-error returns */
+ ret_EOF:
         debug_printf_parse("parse_stream return %d\n", -(end_trigger != NULL));
-        if (end_trigger)
-                return -1;
+ ret:
+        done_word(dest, ctx);
+        done_pipe(ctx, PIPE_SEQ);
+        if (end_trigger) {
+                return -1; /* EOF found while expecting end_trigger */
+        }
         return 0;
 }
 
@@ -4564,7 +4571,6 @@ static int parse_and_run_stream(struct in_str *inp, int parse_flag)
         int rcode;
 
         do {
-                initialize_context(&ctx);
                 update_charmap();
 #if ENABLE_HUSH_INTERACTIVE
                 inp->promptmode = 0; /* PS1 */
@@ -4574,16 +4580,15 @@ static int parse_and_run_stream(struct in_str *inp, int parse_flag)
                  * TEST should be printed */
                 temp.o_assignment = MAYBE_ASSIGNMENT;
                 rcode = parse_stream(&temp, &ctx, inp, ";\n");
+                debug_printf_parse("rcode %d ctx.old_flag %x\n", rcode, ctx.old_flag);
 #if HAS_KEYWORDS
                 if (rcode != 1 && ctx.old_flag != 0) {
                         syntax(NULL);
                 }
 #endif
                 if (rcode != 1 IF_HAS_KEYWORDS(&& ctx.old_flag == 0)) {
-                        done_word(&temp, &ctx);
-                        done_pipe(&ctx, PIPE_SEQ);
                         debug_print_tree(ctx.list_head, 0);
-                        debug_printf_exec("parse_stream_outer: run_and_free_list\n");
+                        debug_printf_exec("parse_and_run_stream: run_and_free_list\n");
                         run_and_free_list(ctx.list_head);
                 } else {
                         /* We arrive here also if rcode == 1 (error in parse_stream) */