4f870496e
Denys Vlasenko
2010-09-10
Subject
hush: do fewer strdups in % and hash expansions
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shell/hush.c +16 -13shell/hush_test/hush-vars/var_bash6.right +5 -0shell/hush_test/hush-vars/var_bash6.tests +9 -0
shell/hush.c+16 -13
| @@ -3800,8 +3800,8 @@ static int encode_string(o_string *as_string, | |
| ch = i_getch(input); /* eat next */ | |
| if (ch == '\n') | |
| goto again; /* skip \<newline> */ | |
| - | } /* else: ch remains == '\\', and we double it */ |
| - | o_addqchr(dest, ch); /* \c if c is s glob char, else just c */ |
| + | } /* else: ch remains == '\\', and we double it below: */ |
| + | o_addqchr(dest, ch); /* \c if c is a glob char, else just c */ |
| nommu_addchr(as_string, ch); | |
| goto again; | |
| } | |
| @@ -4618,26 +4618,29 @@ static NOINLINE const char *expand_one_var(char **to_be_freed_pp, char *arg, cha | |
| * Then var's value is matched to it and matching part removed. | |
| */ | |
| if (val && val[0]) { | |
| + | char *t; |
| char *exp_exp_word; | |
| char *loc; | |
| unsigned scan_flags = pick_scan(exp_op, *exp_word); | |
| if (exp_op == *exp_word) /* ## or %% */ | |
| exp_word++; | |
| - | //TODO: avoid xstrdup unless needed |
| - | // (see HACK ALERT below for an example) |
| - | val = to_be_freed = xstrdup(val); |
| exp_exp_word = encode_then_expand_string(exp_word, /*process_bkslash:*/ 1, /*unbackslash:*/ 1); | |
| if (exp_exp_word) | |
| exp_word = exp_exp_word; | |
| - | loc = scan_and_match(to_be_freed, exp_word, scan_flags); |
| + | /* HACK ALERT. We depend here on the fact that |
| + | * G.global_argv and results of utoa and get_local_var_value |
| + | * are actually in writable memory: |
| + | * scan_and_match momentarily stores NULs there. */ |
| + | t = (char*)val; |
| + | loc = scan_and_match(t, exp_word, scan_flags); |
| //bb_error_msg("op:%c str:'%s' pat:'%s' res:'%s'", | |
| - | // exp_op, to_be_freed, exp_word, loc); |
| + | // exp_op, t, exp_word, loc); |
| free(exp_exp_word); | |
| if (loc) { /* match was found */ | |
| if (scan_flags & SCAN_MATCH_LEFT_HALF) /* #[#] */ | |
| - | val = loc; |
| + | val = loc; /* take right part */ |
| else /* %[%] */ | |
| - | *loc = '\0'; |
| + | val = to_be_freed = xstrndup(val, loc - val); /* left */ |
| } | |
| } | |
| } | |
| @@ -4646,13 +4649,13 @@ static NOINLINE const char *expand_one_var(char **to_be_freed_pp, char *arg, cha | |
| /* It's ${var/[/]pattern[/repl]} thing. | |
| * Note that in encoded form it has TWO parts: | |
| * var/pattern<SPECIAL_VAR_SYMBOL>repl<SPECIAL_VAR_SYMBOL> | |
| + | * and if // is used, it is encoded as \: |
| + | * var\pattern<SPECIAL_VAR_SYMBOL>repl<SPECIAL_VAR_SYMBOL> |
| */ | |
| /* Empty variable always gives nothing: */ | |
| // "v=''; echo ${v/*/w}" prints "", not "w" | |
| if (val && val[0]) { | |
| - | /* It's ${var/[/]pattern[/repl]} thing */ |
| - | /* |
| - | * Pattern is taken literally, while |
| + | /* pattern uses non-standard expansion. |
| * repl should be unbackslashed and globbed | |
| * by the usual expansion rules: | |
| * >az; >bz; | |
| @@ -7339,7 +7342,7 @@ int hush_main(int argc, char **argv) | |
| /* Deal with HUSH_VERSION */ | |
| G.shell_ver.flg_export = 1; | |
| G.shell_ver.flg_read_only = 1; | |
| - | /* Code which handles ${var/P/R} needs writable values for all variables, |
| + | /* Code which handles ${var<op>...} needs writable values for all variables, |
| * therefore we xstrdup: */ | |
| G.shell_ver.varstr = xstrdup(hush_version_str), | |
| G.top_var = &G.shell_ver; | |
shell/hush_test/hush-vars/var_bash6.right+5 -0
| @@ -0,0 +1,5 @@ | |
| + | Expected Actual |
| + | a*z : a*z |
| + | \z : \z |
| + | a1z a2z: a1z a2z |
| + | z : z |
shell/hush_test/hush-vars/var_bash6.tests+9 -0
| @@ -0,0 +1,9 @@ | |
| + | # This testcase checks globbing correctness in ${v/a/b} |
| + | |
| + | >a1z; >a2z; |
| + | echo 'Expected' 'Actual' |
| + | v='a bz'; echo 'a*z :' "${v/a*z/a*z}" |
| + | v='a bz'; echo '\z :' "${v/a*z/\z}" |
| + | v='a bz'; echo 'a1z a2z:' ${v/a*z/a*z} |
| + | v='a bz'; echo 'z :' ${v/a*z/\z} |
| + | rm a1z a2z |