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psql: Add quit/help behavior/hint, for other tool portability

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Issuing 'quit'/'exit' in an empty psql buffer exits psql.  Issuing
'quit'/'exit' in a non-empty psql buffer alone on a line with no prefix
whitespace issues a hint on how to exit.

Also add similar 'help' hints for 'help' in a non-empty psql buffer.

Reported-by: Everaldo Canuto

Discussion: https://postgr.es/m/flat/CALVFHFb-C_5_94hueWg6Dd0zu7TfbpT7hzsh9Zf0DEDOSaAnfA%40mail.gmail.com

Author: original author Robert Haas, modified by me
This commit is contained in:
Bruce Momjian 2018-02-01 08:30:43 -05:00
parent eab30cc6b5
commit df9f599bc6
1 changed files with 100 additions and 13 deletions
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113
src/bin/psql/mainloop.c
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@ -216,21 +216,108 @@ MainLoop(FILE *source)
continue;
}
/* A request for help? Be friendly and give them some guidance */
if (pset.cur_cmd_interactive && query_buf->len == 0 &&
pg_strncasecmp(line, "help", 4) == 0 &&
(line[4] == '\0' || line[4] == ';' || isspace((unsigned char) line[4])))
/* Recognize "help", "quit", "exit" only in interactive mode */
if (pset.cur_cmd_interactive)
{
free(line);
puts(_("You are using psql, the command-line interface to PostgreSQL."));
printf(_("Type: \\copyright for distribution terms\n"
" \\h for help with SQL commands\n"
" \\? for help with psql commands\n"
" \\g or terminate with semicolon to execute query\n"
" \\q to quit\n"));
char *first_word = line;
char *rest_of_line = NULL;
bool found_help = false;
bool found_exit_or_quit = false;
fflush(stdout);
continue;
/* Search for the words we recognize; must be first word */
if (pg_strncasecmp(first_word, "help", 4) == 0)
{
rest_of_line = first_word + 4;
found_help = true;
}
else if (pg_strncasecmp(first_word, "exit", 4) == 0 ||
pg_strncasecmp(first_word, "quit", 4) == 0)
{
rest_of_line = first_word + 4;
found_exit_or_quit = true;
}
/*
* If we found a command word, check whether the rest of the line
* contains only whitespace plus maybe one semicolon. If not,
* ignore the command word after all.
*/
if (rest_of_line != NULL)
{
/*
* Ignore unless rest of line is whitespace, plus maybe one
* semicolon
*/
while (isspace((unsigned char) *rest_of_line))
++rest_of_line;
if (*rest_of_line == ';')
++rest_of_line;
while (isspace((unsigned char) *rest_of_line))
++rest_of_line;
if (*rest_of_line != '\0')
{
found_help = false;
found_exit_or_quit = false;
}
}
/*
* "help" is only a command when the query buffer is empty, but we
* emit a one-line message even when it isn't to help confused
* users. The text is still added to the query buffer in that
* case.
*/
if (found_help)
{
if (query_buf->len != 0)
#ifndef WIN32
puts(_("Use \\? for help or press control-C to clear the input buffer."));
#else
puts(_("Use \\? for help."));
#endif
else
{
puts(_("You are using psql, the command-line interface to PostgreSQL."));
printf(_("Type: \\copyright for distribution terms\n"
" \\h for help with SQL commands\n"
" \\? for help with psql commands\n"
" \\g or terminate with semicolon to execute query\n"
" \\q to quit\n"));
free(line);
fflush(stdout);
continue;
}
}
/*
* "quit" and "exit" are only commands when the query buffer is
* empty, but we emit a one-line message even when it isn't to
* help confused users. The text is still added to the query
* buffer in that case.
*/
if (found_exit_or_quit)
{
if (query_buf->len != 0)
{
if (prompt_status == PROMPT_READY ||
prompt_status == PROMPT_CONTINUE ||
prompt_status == PROMPT_PAREN)
puts(_("Use \\q to quit."));
else
#ifndef WIN32
puts(_("Use control-D to quit."));
#else
puts(_("Use control-C to quit."));
#endif
}
else
{
/* exit app */
free(line);
fflush(stdout);
successResult = EXIT_SUCCESS;
break;
}
}
}
/* echo back if flag is set, unless interactive */