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hush: remove code to track PS1/2 values dynamically - it's too much work

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Assignments / exports / unsets of variables are far more frequent than
prompt printing, and if we show prompt, we are likely to be limited by
user typing speed - do not optimize for that scenario.
Just re-query $PS1 / $PS2 values when need to show the prompt.

function                                             old     new   delta
fgetc_interactive                                    236     259     +23
set_vars_and_save_old                                150     147      -3
pseudo_exec_argv                                     597     594      -3
hush_main                                           1110    1105      -5
enter_var_nest_level                                  38      32      -6
builtin_local                                         56      50      -6
run_pipe                                            1857    1834     -23
leave_var_nest_level                                 127      98     -29
handle_changed_special_names                         111      79     -32
cmdedit_update_prompt                                 57       -     -57
------------------------------------------------------------------------------
(add/remove: 0/1 grow/shrink: 1/8 up/down: 23/-164)          Total: -141 bytes

Signed-off-by: Denys Vlasenko <vda.linux@googlemail.com>
This commit is contained in:
Denys Vlasenko 2019-05-16 15:39:19 +02:00
parent a51eec0b5a
commit 4ebcdf7396
1 changed files with 21 additions and 61 deletions
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82
shell/hush.c
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@ -854,8 +854,7 @@ struct globals {
/* 'interactive_fd' is a fd# open to ctty, if we have one
* _AND_ if we decided to act interactively */
int interactive_fd;
const char *PS1;
IF_FEATURE_EDITING_FANCY_PROMPT(const char *PS2;)
IF_NOT_FEATURE_EDITING_FANCY_PROMPT(char *PS1;)
# define G_interactive_fd (G.interactive_fd)
#else
# define G_interactive_fd 0
@ -1448,13 +1447,6 @@ static void syntax_error_unexpected_ch(unsigned lineno UNUSED_PARAM, int ch)
#endif
#if ENABLE_HUSH_INTERACTIVE && ENABLE_FEATURE_EDITING_FANCY_PROMPT
static void cmdedit_update_prompt(void);
#else
# define cmdedit_update_prompt() ((void)0)
#endif
/* Utility functions
*/
/* Replace each \x with x in place, return ptr past NUL. */
@ -2248,33 +2240,22 @@ static const char* FAST_FUNC get_local_var_value(const char *name)
return NULL;
}
#if (ENABLE_HUSH_INTERACTIVE && ENABLE_FEATURE_EDITING_FANCY_PROMPT) \
|| (ENABLE_HUSH_LINENO_VAR || ENABLE_HUSH_GETOPTS)
#if ENABLE_HUSH_LINENO_VAR || ENABLE_HUSH_GETOPTS
static void handle_changed_special_names(const char *name, unsigned name_len)
{
if (ENABLE_HUSH_INTERACTIVE && ENABLE_FEATURE_EDITING_FANCY_PROMPT
&& name_len == 3 && name[0] == 'P' && name[1] == 'S'
) {
if (G_interactive_fd)
cmdedit_update_prompt();
return;
}
if ((ENABLE_HUSH_LINENO_VAR || ENABLE_HUSH_GETOPTS)
&& name_len == 6
) {
#if ENABLE_HUSH_LINENO_VAR
if (name_len == 6) {
# if ENABLE_HUSH_LINENO_VAR
if (strncmp(name, "LINENO", 6) == 0) {
G.lineno_var = NULL;
return;
}
#endif
#if ENABLE_HUSH_GETOPTS
# endif
# if ENABLE_HUSH_GETOPTS
if (strncmp(name, "OPTIND", 6) == 0) {
G.getopt_count = 0;
return;
}
#endif
# endif
}
}
#else
@ -2470,7 +2451,7 @@ static int unset_local_var_len(const char *name, int name_len)
cur_pp = &cur->next;
}
/* Handle "unset PS1" et al even if did not find the variable to unset */
/* Handle "unset LINENO" et al even if did not find the variable to unset */
handle_changed_special_names(name, name_len);
return EXIT_SUCCESS;
@ -2500,11 +2481,6 @@ static void add_vars(struct variable *var)
} else {
debug_printf_env("%s: restoring variable '%s'/%u\n", __func__, var->varstr, var->var_nest_level);
}
/* Testcase (interactive):
* f() { local PS1='\w \$ '; }; f
* the below call is needed to notice restored PS1 when f returns.
*/
handle_changed_special_names(var->varstr, endofname(var->varstr) - var->varstr);
var = next;
}
}
@ -2594,36 +2570,27 @@ static void reinit_unicode_for_hush(void)
* \
* It exercises a lot of corner cases.
*/
# if ENABLE_FEATURE_EDITING_FANCY_PROMPT
static void cmdedit_update_prompt(void)
{
G.PS1 = get_local_var_value("PS1");
if (G.PS1 == NULL)
G.PS1 = "";
G.PS2 = get_local_var_value("PS2");
if (G.PS2 == NULL)
G.PS2 = "";
}
# endif
static const char *setup_prompt_string(void)
{
const char *prompt_str;
debug_printf_prompt("%s promptmode:%d\n", __func__, G.promptmode);
IF_FEATURE_EDITING_FANCY_PROMPT( prompt_str = G.PS2;)
IF_NOT_FEATURE_EDITING_FANCY_PROMPT(prompt_str = "> ";)
# if ENABLE_FEATURE_EDITING_FANCY_PROMPT
prompt_str = get_local_var_value(G.promptmode == 0 ? "PS1" : "PS2");
if (!prompt_str)
prompt_str = "";
# else
prompt_str = "> "; /* if PS2, else... */
if (G.promptmode == 0) { /* PS1 */
if (!ENABLE_FEATURE_EDITING_FANCY_PROMPT) {
/* No fancy prompts supported, (re)generate "CURDIR $ " by hand */
free((char*)G.PS1);
/* bash uses $PWD value, even if it is set by user.
* It uses current dir only if PWD is unset.
* We always use current dir. */
G.PS1 = xasprintf("%s %c ", get_cwd(0), (geteuid() != 0) ? '$' : '#');
}
prompt_str = G.PS1;
/* No fancy prompts supported, (re)generate "CURDIR $ " by hand */
free(G.PS1);
/* bash uses $PWD value, even if it is set by user.
* It uses current dir only if PWD is unset.
* We always use current dir. */
G.PS1 = xasprintf("%s %c ", get_cwd(0), (geteuid() != 0) ? '$' : '#');
}
# endif
debug_printf("prompt_str '%s'\n", prompt_str);
return prompt_str;
}
@ -7904,11 +7871,6 @@ static void remove_nested_vars(void)
*cur_pp = cur->next;
/* Free */
if (!cur->max_len) {
/* Testcase (interactive):
* f() { local PS1='\w \$ '; }; f
* we should forget local PS1:
*/
handle_changed_special_names(cur->varstr, endofname(cur->varstr) - cur->varstr);
debug_printf_env("freeing nested '%s'/%u\n", cur->varstr, cur->var_nest_level);
free(cur->varstr);
}
@ -9997,8 +9959,6 @@ int hush_main(int argc, char **argv)
#endif
/* Initialize some more globals to non-zero values */
cmdedit_update_prompt();
die_func = restore_ttypgrp_and__exit;
/* Shell is non-interactive at first. We need to call