libsmartcols: add header-repeat feature

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

5 files changed, 67 insertions, 3 deletions

diff --git a/libsmartcols/src/libsmartcols.h.in b/libsmartcols/src/libsmartcols.h.in
index cfe2439ef..bce2cc725 100644
--- a/libsmartcols/src/libsmartcols.h.in
+++ b/libsmartcols/src/libsmartcols.h.in
@@ -219,6 +219,7 @@ extern int scols_table_is_raw(const struct libscols_table *tb);
 extern int scols_table_is_ascii(const struct libscols_table *tb);
 extern int scols_table_is_json(const struct libscols_table *tb);
 extern int scols_table_is_noheadings(const struct libscols_table *tb);
+extern int scols_table_is_header_repeat(const struct libscols_table *tb);
 extern int scols_table_is_empty(const struct libscols_table *tb);
 extern int scols_table_is_export(const struct libscols_table *tb);
 extern int scols_table_is_maxout(const struct libscols_table *tb);
@@ -231,6 +232,7 @@ extern int scols_table_enable_raw(struct libscols_table *tb, int enable);
 extern int scols_table_enable_ascii(struct libscols_table *tb, int enable);
 extern int scols_table_enable_json(struct libscols_table *tb, int enable);
 extern int scols_table_enable_noheadings(struct libscols_table *tb, int enable);
+extern int scols_table_enable_header_repeat(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);
diff --git a/libsmartcols/src/libsmartcols.sym b/libsmartcols/src/libsmartcols.sym
index 7b9a3d97b..fec33cbfd 100644
--- a/libsmartcols/src/libsmartcols.sym
+++ b/libsmartcols/src/libsmartcols.sym
@@ -171,4 +171,6 @@ global:
 SMARTCOLS_2.31 {
 	scols_table_set_termheight;
 	scols_table_get_termheight;
+	scols_table_is_header_repeat;
+	scols_table_enable_header_repeat;
 } SMARTCOLS_2.30;
diff --git a/libsmartcols/src/smartcolsP.h b/libsmartcols/src/smartcolsP.h
index 1a749b247..65009779a 100644
--- a/libsmartcols/src/smartcolsP.h
+++ b/libsmartcols/src/smartcolsP.h
@@ -164,12 +164,16 @@ struct libscols_table {
 	int	indent_last_sep;/* last printed has been line separator */
 	int	format;		/* SCOLS_FMT_* */
 
+	size_t	termlines_used;	/* printed line counter */
+	size_t	header_next;	/* where repeat header */
+
 	/* flags */
 	unsigned int	ascii		:1,	/* don't use unicode */
 			colors_wanted	:1,	/* enable colors */
 			is_term		:1,	/* isatty() */
 			padding_debug	:1,	/* output visible padding chars */
 			maxout		:1,	/* maximize output */
+			header_repeat   :1,     /* print header after libscols_table->termheight */
 			header_printed  :1,	/* header already printed */
 			priv_symbols	:1,	/* default private symbols */
 			no_headings	:1,	/* don't print header */
diff --git a/libsmartcols/src/table.c b/libsmartcols/src/table.c
index dd412b220..3306ff57c 100644
--- a/libsmartcols/src/table.c
+++ b/libsmartcols/src/table.c
@@ -1033,6 +1033,28 @@ int scols_table_enable_noheadings(struct libscols_table *tb, int enable)
 }
 
 /**
+ * scols_table_enable_header_repeat:
+ * @tb: table
+ * @enable: 1 or 0
+ *
+ * Enable/disable header line repeat. The header line is printed only once by
+ * default.  Note that the flag will be silently ignored and disabled if the
+ * output is not on terminal or output format is JSON, raw, etc.
+ *
+ * Returns: 0 on success, negative number in case of an error.
+ *
+ * Since: 2.31
+ */
+int scols_table_enable_header_repeat(struct libscols_table *tb, int enable)
+{
+	if (!tb)
+		return -EINVAL;
+	DBG(TAB, ul_debugobj(tb, "header-repeat: %s", enable ? "ENABLE" : "DISABLE"));
+	tb->header_repeat = enable ? 1 : 0;
+	return 0;
+}
+
+/**
  * scols_table_enable_maxout:
  * @tb: table
  * @enable: 1 or 0
@@ -1129,6 +1151,19 @@ int scols_table_is_noheadings(const struct libscols_table *tb)
 }
 
 /**
+ * scols_table_is_header_repeat
+ * @tb: table
+ *
+ * Returns: 1 if header repeat is enabled.
+ *
+ * Since: 2.31
+ */
+int scols_table_is_header_repeat(const struct libscols_table *tb)
+{
+	return tb->header_repeat;
+}
+
+/**
  * scols_table_is_export:
  * @tb: table
  *
diff --git a/libsmartcols/src/table_print.c b/libsmartcols/src/table_print.c
index 8cd737c8b..8e37c80cb 100644
--- a/libsmartcols/src/table_print.c
+++ b/libsmartcols/src/table_print.c
@@ -43,6 +43,9 @@
 #define cellpadding_symbol(tb)  ((tb)->padding_debug ? "." : \
 				 ((tb)->symbols->cell_padding ? (tb)->symbols->cell_padding: " "))
 
+#define want_repeat_header(tb)	(!(tb)->header_repeat || (tb)->header_next <= (tb)->termlines_used)
+
+
 /* This is private struct to work with output data */
 struct libscols_buffer {
 	char	*begin;		/* begin of the buffer */
@@ -307,6 +310,7 @@ static void print_newline_padding(struct libscols_table *tb,
 	assert(cl);
 
 	fputs(linesep(tb), tb->out);		/* line break */
+	tb->termlines_used++;
 
 	/* fill cells after line break */
 	for (i = 0; i <= (size_t) cl->seqnum; i++)
@@ -650,6 +654,7 @@ static void fput_children_open(struct libscols_table *tb)
 	fputs(linesep(tb), tb->out);
 	tb->indent_last_sep = 1;
 	tb->indent++;
+	tb->termlines_used++;
 }
 
 static void fput_children_close(struct libscols_table *tb)
@@ -684,8 +689,10 @@ static void fput_line_close(struct libscols_table *tb, int last, int last_in_tab
 		if (!tb->no_linesep)
 			fputs(linesep(tb), tb->out);
 
-	} else if (tb->no_linesep == 0 && last_in_table == 0)
+	} else if (tb->no_linesep == 0 && last_in_table == 0) {
 		fputs(linesep(tb), tb->out);
+		tb->termlines_used++;
+	}
 
 	tb->indent_last_sep = 1;
 }
@@ -724,6 +731,7 @@ static int print_line(struct libscols_table *tb,
 	while (rc == 0 && pending) {
 		pending = 0;
 		fputs(linesep(tb), tb->out);
+		tb->termlines_used++;
 		scols_reset_iter(&itr, SCOLS_ITER_FORWARD);
 		while (rc == 0 && scols_table_next_column(tb, &itr, &cl) == 0) {
 			if (scols_column_is_hidden(cl))
@@ -833,7 +841,7 @@ static int print_header(struct libscols_table *tb, struct libscols_buffer *buf)
 
 	assert(tb);
 
-	if (tb->header_printed == 1 ||
+	if ((tb->header_printed == 1 && tb->header_repeat == 0) ||
 	    scols_table_is_noheadings(tb) ||
 	    scols_table_is_export(tb) ||
 	    scols_table_is_json(tb) ||
@@ -852,13 +860,20 @@ static int print_header(struct libscols_table *tb, struct libscols_buffer *buf)
 			rc = print_data(tb, cl, NULL, &cl->header, buf);
 	}
 
-	if (rc == 0)
+	if (rc == 0) {
 		fputs(linesep(tb), tb->out);
+		tb->termlines_used++;
+	}
 
 	tb->header_printed = 1;
+	tb->header_next = tb->termlines_used + tb->termheight;
+	if (tb->header_repeat)
+		DBG(TAB, ul_debugobj(tb, "\tnext header: %zu [current=%zu]",
+					tb->header_next, tb->termlines_used));
 	return rc;
 }
 
+
 static int print_range(	struct libscols_table *tb,
 			struct libscols_buffer *buf,
 			struct libscols_iter *itr,
@@ -879,6 +894,9 @@ static int print_range(	struct libscols_table *tb,
 
 		if (end && ln == end)
 			break;
+
+		if (!last && want_repeat_header(tb))
+			print_header(tb, buf);
 	}
 
 	return rc;
@@ -1398,6 +1416,9 @@ static int initialize_printing(struct libscols_table *tb, struct libscols_buffer
 	} else
 		bufsz = BUFSIZ;
 
+	if (!tb->is_term || tb->format != SCOLS_FMT_HUMAN || scols_table_is_tree(tb))
+		tb->header_repeat = 0;
+
 	/*
 	 * Estimate extra space necessary for tree, JSON or another output
 	 * decoration.