column: fix leading space characters bug

The bug has been introduced during column(1) rewrite. The function
read_input() need to skip leading space only temporary to detect empty
lines, but the rest of the code has to use the original buffer (line).
I've tried to fix one of the symptoms by 5c7b67fbbf
(alter), but this solution is unnecessary and too complex.

Changes:

* don't ignore leading space
* remove unnecessary stuff introduced by 5c7b67fbbf
* fix regression test with incorrect separator

Addresses: https://github.com/karelzak/util-linux/issues/575
Addresses: https://bugzilla.redhat.com/show_bug.cgi?id=1560283
Signed-off-by: Karel Zak <kzak@redhat.com>

Documentation/TODO

@@ -13,9 +13,6 @@ column
    - add option to NOT ignore empty lines
      https://github.com/karelzak/util-linux/issues/593
 
-   - add option to NOT ignore line leading empty space
-     https://bugzilla.redhat.com/show_bug.cgi?id=1560283
-
 script
 ------
    - (!) add terminal type ($TERM), columns and lines to the header line, something like:

tests/expected/column/table-input-separator-space

@@ -1,5 +1,5 @@
 AAA	BBBB	C	DDDD
-BBB	CCCC	DDD
+	BBB	CCCC	DDD
 AA	BB		DD
 AAAA	B	CC	D
 AA		CC	DD

tests/ts/column/table

@@ -37,7 +37,7 @@ $TS_CMD_COLUMN --separator ',' --table $TS_SELF/files/table-sep >> $TS_OUTPUT 2>
 ts_finalize_subtest
 
 ts_init_subtest "input-separator-space"
-$TS_CMD_COLUMN --separator ',' --table $TS_SELF/files/table-sep-space >> $TS_OUTPUT 2>&1
+$TS_CMD_COLUMN --separator "$(echo -e '\t')" --table $TS_SELF/files/table-sep-space >> $TS_OUTPUT 2>&1
 ts_finalize_subtest
 
 ts_init_subtest "long"

text-utils/column.c

@@ -86,7 +86,6 @@ struct column_control {
 	const char *tree_parent;
 
 	wchar_t *input_separator;
-	char *input_separator_raw;
 	const char *output_separator;
 
 	wchar_t	**ents;		/* input entries */
@@ -96,7 +95,6 @@ struct column_control {
 	unsigned int greedy :1,
 		     json :1,
 		     header_repeat :1,
-		     input_sep_space : 1,	/* input separator contains space chars */
 		     tab_noheadings :1;
 };
 
@@ -470,19 +468,7 @@ static int read_input(struct column_control *ctl, FILE *fp)
 	char *buf = NULL;
 	size_t bufsz = 0;
 	size_t maxents = 0;
-	int rc = 0, is_space_sep = 0;
-
-	/* Check if columns separator contains spaces chars */
-	if (ctl->mode == COLUMN_MODE_TABLE && ctl->input_separator_raw) {
-		char *p;
-
-		for (p = ctl->input_separator_raw; *p; p++) {
-			if (isspace(*p)) {
-				is_space_sep = 1;
-				break;
-			}
-		}
-	}
+	int rc = 0;
 
 	/* Read input */
 	do {
@@ -496,19 +482,6 @@ static int read_input(struct column_control *ctl, FILE *fp)
 			err(EXIT_FAILURE, _("read failed"));
 		}
 		str = (char *) skip_space(buf);
-
-		/* The table columns separator could be a space. In this case
-		 * don't skip the separator if at begin of the line. For example:
-		 *
-		 * echo -e "\tcol1\tcol2\nrow\t1\t2" \
-		 *	| column -t -s "$(echo -e '\t')" --table-columns A,B,C
-		 */
-		if (is_space_sep && str > buf) {
-			char *x = strpbrk(buf, ctl->input_separator_raw);
-			if (x && x < str)
-				str = x;
-		}
-
 		if (str) {
 			p = strchr(str, '\n');
 			if (p)
@@ -517,13 +490,13 @@ static int read_input(struct column_control *ctl, FILE *fp)
 		if (!str || !*str)
 			continue;
 
-		wcs = mbs_to_wcs(str);
+		wcs = mbs_to_wcs(buf);
 		if (!wcs) {
 			/*
 			 * Convert broken sequences to \x<hex> and continue.
 			 */
 			size_t tmpsz = 0;
-			char *tmp = mbs_invalid_encode(str, &tmpsz);
+			char *tmp = mbs_invalid_encode(buf, &tmpsz);
 
 			if (!tmp)
 				err(EXIT_FAILURE, _("read failed"));
@@ -720,7 +693,6 @@ int main(int argc, char **argv)
 
 	ctl.output_separator = "  ";
 	ctl.input_separator = mbs_to_wcs("\t ");
-	ctl.input_separator_raw = xstrdup("\t ");
 
 	while ((c = getopt_long(argc, argv, "c:dE:eH:hi:JN:n:O:o:p:R:r:s:T:tVW:x", longopts, NULL)) != -1) {
 
@@ -775,9 +747,7 @@ int main(int argc, char **argv)
 			break;
 		case 's':
 			free(ctl.input_separator);
-			free(ctl.input_separator_raw);
 			ctl.input_separator = mbs_to_wcs(optarg);
-			ctl.input_separator_raw = xstrdup(optarg);
 			ctl.greedy = 0;
 			break;
 		case 'T':