libsmartcols: support continuous printing

This patch allows to disable line-breaks. This feature is usable when
you want to re-print the same line more than once -- move terminal
cursor to the begin of the line and print again and again (aka
progress bar).

Signed-off-by: Karel Zak <kzak@redhat.com>

libsmartcols/docs/libsmartcols-sections.txt

@@ -103,6 +103,7 @@ scols_table_enable_export
 scols_table_enable_json
 scols_table_enable_maxout
 scols_table_enable_noheadings
+scols_table_enable_nolinesep
 scols_table_enable_nowrap
 scols_table_enable_raw
 scols_table_get_column

libsmartcols/src/cell.c

@@ -56,7 +56,7 @@ int scols_reset_cell(struct libscols_cell *ce)
  * @ce: a pointer to a struct libscols_cell instance
  * @str: data (used for scols_print_table())
  *
- * Stores a copy of the @str in @ce.
+ * Stores a copy of the @str in @ce, the old data are deallocated by free().
  *
  * Returns: 0, a negative value in case of an error.
  */

libsmartcols/src/libsmartcols.h.in

@@ -210,6 +210,7 @@ extern int scols_table_enable_noheadings(struct libscols_table *tb, int enable);
 extern int scols_table_enable_export(struct libscols_table *tb, int enable);
 extern int scols_table_enable_maxout(struct libscols_table *tb, int enable);
 extern int scols_table_enable_nowrap(struct libscols_table *tb, int enable);
+extern int scols_table_enable_nolinesep(struct libscols_table *tb, int enable);
 
 extern int scols_table_set_column_separator(struct libscols_table *tb, const char *sep);
 extern int scols_table_set_line_separator(struct libscols_table *tb, const char *sep);

libsmartcols/src/libsmartcols.sym

@@ -133,4 +133,5 @@ global:
 	scols_cell_get_flags;
 	scols_cell_set_flags;
 	scols_table_print_range;
+	scols_table_enable_nolinesep;
 } SMARTCOLS_2.27;

libsmartcols/src/smartcolsP.h

@@ -156,7 +156,9 @@ struct libscols_table {
 			colors_wanted	:1,	/* enable colors */
 			is_term		:1,	/* isatty() */
 			maxout		:1,	/* maximalize output */
+			header_printed  :1,	/* header already printed */
 			no_headings	:1,	/* don't print header */
+			no_linesep	:1,	/* don't print line separator */
 			no_wrap		:1;	/* never wrap lines */
 };
 

libsmartcols/src/table.c

@@ -707,6 +707,27 @@ int scols_table_set_symbols(struct libscols_table *tb,
 	return 0;
 }
 
+/**
+ * scols_table_enable_nolinesep
+ * @tb: table
+ * @enable: 1 or 0
+ *
+ * Enable/disable line separator printing. This is usefull if you want to
+ * re-printing the same line more than once (e.g. progress bar). Don't use it
+ * if you're not sure.
+ *
+ * Returns: 0 on success, negative number in case of an error.
+ */
+int scols_table_enable_nolinesep(struct libscols_table *tb, int enable)
+{
+	if (!tb)
+		return -EINVAL;
+
+	DBG(TAB, ul_debugobj(tb, "nolinesep: %s", enable ? "ENABLE" : "DISABLE"));
+	tb->no_linesep = enable;
+	return 0;
+}
+
 /**
  * scols_table_enable_colors:
  * @tb: table

libsmartcols/src/table_print.c

@@ -645,7 +645,8 @@ static void fput_line_close(struct libscols_table *tb, int last)
 			fput_indent(tb);
 		fputs(last ? "}" : "},", tb->out);
 	}
-	fputs(linesep(tb), tb->out);
+	if (!tb->no_linesep)
+		fputs(linesep(tb), tb->out);
 	tb->indent_last_sep = 1;
 }
 
@@ -778,7 +779,8 @@ static int print_header(struct libscols_table *tb, struct libscols_buffer *buf)
 
 	assert(tb);
 
-	if (scols_table_is_noheadings(tb) ||
+	if (tb->header_printed == 1 ||
+	    scols_table_is_noheadings(tb) ||
 	    scols_table_is_export(tb) ||
 	    scols_table_is_json(tb) ||
 	    list_empty(&tb->tb_lines))
@@ -798,6 +800,8 @@ static int print_header(struct libscols_table *tb, struct libscols_buffer *buf)
 
 	if (rc == 0)
 		fputs(linesep(tb), tb->out);
+
+	tb->header_printed = 1;
 	return rc;
 }
 
@@ -1306,6 +1310,9 @@ err:
  * @start: first printed line or NULL to print from the beggin of the table
  * @end: last printed line or NULL to print all from start.
  *
+ * If the start is the first line in the table than prints table header too.
+ * The header is printed only once.
+ *
  * Returns: 0, a negative value in case of an error.
  */
 int scols_table_print_range(	struct libscols_table *tb,
@@ -1332,10 +1339,16 @@ int scols_table_print_range(	struct libscols_table *tb,
 	} else
 		scols_reset_iter(&itr, SCOLS_ITER_FORWARD);
 
-	rc = print_range(tb, buf, &itr, end);
+	if (itr.p == tb->tb_lines.next) {
+		rc = print_header(tb, buf);
+		if (rc)
+			goto done;
+	}
 
+	rc = print_range(tb, buf, &itr, end);
+done:
 	free_buffer(buf);
-	return 0;
+	return rc;
 }
 
 /**
@@ -1361,6 +1374,7 @@ int scols_print_table(struct libscols_table *tb)
 		return 0;
 	}
 
+	tb->header_printed = 0;
 	rc = initialize_printting(tb, &buf);
 	if (rc)
 		return rc;