libsmartcols: add lines grouping support

For some use-case we need to describe M:N relation between output
lines. The nice examples are RAIDs or multi-path devices in lsblk
output.

    NAME                 MAJ:MIN RM   SIZE RO TYPE  MOUNTPOINT
    loop0                  7:0    0 955.7M  0 loop
┌┈▶ ├─test-thin-metadata 253:0    0     2M  0 dm
└┬▶ └─test-thin-data     253:1    0 953.7M  0 dm
 └┈┈test-thin-pool       253:2    0 953.7M  0 dm

In this example two line (test-thin-metadata and test-thin-data) are
parents for another line (test-thin-pool). The new API uses term "group"
for parental line -- the number of group members is unlimited and every
group has at least one child.

It's possible that group's child is member of another group:

       NAME                 MAJ:MIN RM   SIZE RO TYPE  MOUNTPOINT
       loop0                  7:0    0 955.7M  0 loop
   ┌┈▶ ├─test-thin-metadata 253:0    0     2M  0 dm
   └┬▶ └─test-thin-data     253:1    0 953.7M  0 dm
┌┈▶ └┈┈test-thin-pool       253:2    0 953.7M  0 dm
┆      └─test-thin          253:3    0 190.8M  0 dm
└┬▶    loop1                  7:1    0 190.8M  0 loop
 └┈┈┈┈┈test-thin-extsnap    253:4    0 190.8M  0 dm

For now multi-group relation is unsupported and one line can be member
of one group only. The library API and printing code is ready to
support this feature, but not sure if we really need it. All what is
necessary is to create array of groups in the line struct.

Note that grouping is independent on standard parent->child relations
between lines and grouping can connect arbitrary lines. The
restriction is only that group child cannot be child of another line
or child of another group. These cross reference are (and probably
will be) impossible.

The patch is relative large, but easy to review. Changes:

* add new UTF symbols
* add scols_symbols_set_group_* public API to modify new symbols
* add struct libscols_group, used only internally

* add "grpset" array to table struct -- the array is used to keep
position of the group in the output. Every active group uses three
items in the grpset. If there is more overlapping groups than bigger
grpset is allocated.

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

1 files changed, 85 insertions, 15 deletions

diff --git a/libsmartcols/src/table.c b/libsmartcols/src/table.c
index 14ff9de4b..e4f27a916 100644
--- a/libsmartcols/src/table.c
+++ b/libsmartcols/src/table.c
@@ -29,13 +29,17 @@
 #include "smartcolsP.h"
 
 #ifdef HAVE_WIDECHAR
-#define UTF_V	"\342\224\202"	/* U+2502, Vertical line drawing char |  */
-#define UTF_VR	"\342\224\234"	/* U+251C, Vertical and right         |- */
-#define UTF_VL  "\342\224\244"  /* U+2524  Vertical and left         -|  */
-#define UTF_H	"\342\224\200"	/* U+2500, Horizontal                 -  */
-#define UTF_UR	"\342\224\224"	/* U+2514, Up and right              '-  */
-#define UTF_UL  "\342\224\230"  /* U+2518, Up and left                -' */
-#define UTF_DL  "\342\224\220"  /* U+2510, Down and left              -, */
+#define UTF_V	"\342\224\202"	/* U+2502, Vertical line drawing char  |   */
+#define UTF_VR	"\342\224\234"	/* U+251C, Vertical and right          |-  */
+#define UTF_H	"\342\224\200"	/* U+2500, Horizontal                  -   */
+#define UTF_UR	"\342\224\224"	/* U+2514, Up and right                '-  */
+
+#define UTF_V3  "\342\224\206"  /* U+2506 Triple Dash Vertical          |  */
+#define UTF_H3  "\342\224\210"  /* U+2504 Triple Dash Horizontal        -  */
+#define UTF_DR  "\342\224\214"  /* U+250C Down and Right                ,- */
+#define UTF_DH  "\342\224\254"  /* U+252C Down and Horizontal           |' */
+
+#define UTF_TR  "\342\226\266"  /* U+25B6 Black Right-Pointing Triangle  >  */
 #endif /* !HAVE_WIDECHAR */
 
 #define is_last_column(_tb, _cl) \
@@ -79,6 +83,7 @@ struct libscols_table *scols_new_table(void)
 
 	INIT_LIST_HEAD(&tb->tb_lines);
 	INIT_LIST_HEAD(&tb->tb_columns);
+	INIT_LIST_HEAD(&tb->tb_groups);
 
 	DBG(TAB, ul_debugobj(tb, "alloc"));
 	ON_DBG(INIT, check_padding_debug(tb));
@@ -98,6 +103,17 @@ void scols_ref_table(struct libscols_table *tb)
 		tb->refcount++;
 }
 
+static void scols_table_remove_groups(struct libscols_table *tb)
+{
+	while (!list_empty(&tb->tb_groups)) {
+		struct libscols_group *gr = list_entry(tb->tb_groups.next,
+							struct libscols_group, gr_groups);
+		scols_group_remove_children(gr);
+		scols_group_remove_members(gr);
+		scols_unref_group(gr);
+	}
+}
+
 /**
  * scols_unref_table:
  * @tb: a pointer to a struct libscols_table instance
@@ -108,16 +124,40 @@ void scols_ref_table(struct libscols_table *tb)
 void scols_unref_table(struct libscols_table *tb)
 {
 	if (tb && (--tb->refcount <= 0)) {
-		DBG(TAB, ul_debugobj(tb, "dealloc"));
+		DBG(TAB, ul_debugobj(tb, "dealloc <-"));
+		scols_table_remove_groups(tb);
 		scols_table_remove_lines(tb);
 		scols_table_remove_columns(tb);
 		scols_unref_symbols(tb->symbols);
 		scols_reset_cell(&tb->title);
+		free(tb->grpset);
 		free(tb->linesep);
 		free(tb->colsep);
 		free(tb->name);
 		free(tb);
+		DBG(TAB, ul_debug("<- done"));
+	}
+}
+
+/* Private API */
+int scols_table_next_group(struct libscols_table *tb,
+			  struct libscols_iter *itr,
+			  struct libscols_group **gr)
+{
+	int rc = 1;
+
+	if (!tb || !itr || !gr)
+		return -EINVAL;
+	*gr = NULL;
+
+	if (!itr->head)
+		SCOLS_ITER_INIT(itr, &tb->tb_groups);
+	if (itr->p != itr->head) {
+		SCOLS_ITER_ITERATE(itr, *gr, struct libscols_group, gr_groups);
+		rc = 0;
 	}
+
+	return rc;
 }
 
 /**
@@ -801,15 +841,35 @@ int scols_table_set_default_symbols(struct libscols_table *tb)
 #if defined(HAVE_WIDECHAR)
 	if (!scols_table_is_ascii(tb) &&
 	    !strcmp(nl_langinfo(CODESET), "UTF-8")) {
+		/* tree chart */
 		scols_symbols_set_branch(sy, UTF_VR UTF_H);
 		scols_symbols_set_vertical(sy, UTF_V " ");
 		scols_symbols_set_right(sy, UTF_UR UTF_H);
+		/* groups chart */
+		scols_symbols_set_group_horizontal(sy, UTF_H3);
+		scols_symbols_set_group_vertical(sy, UTF_V3);
+
+		scols_symbols_set_group_first_member(sy,  UTF_DR UTF_H3 UTF_TR);
+		scols_symbols_set_group_last_member(sy,   UTF_UR UTF_DH UTF_TR);
+		scols_symbols_set_group_middle_member(sy, UTF_VR UTF_H3 UTF_TR);
+		scols_symbols_set_group_last_child(sy,    UTF_UR UTF_H3);
+		scols_symbols_set_group_middle_child(sy,  UTF_VR UTF_H3);
 	} else
 #endif
 	{
+		/* tree chart */
 		scols_symbols_set_branch(sy, "|-");
 		scols_symbols_set_vertical(sy, "| ");
 		scols_symbols_set_right(sy, "`-");
+		/* groups chart */
+		scols_symbols_set_group_horizontal(sy, "-");
+		scols_symbols_set_group_vertical(sy, "|");
+
+		scols_symbols_set_group_first_member(sy, ",->");
+		scols_symbols_set_group_last_member(sy, "'->");
+		scols_symbols_set_group_middle_member(sy, "|->");
+		scols_symbols_set_group_last_child(sy, "`-");
+		scols_symbols_set_group_middle_child(sy, "|-");
 	}
 	scols_symbols_set_title_padding(sy, " ");
 	scols_symbols_set_cell_padding(sy, " ");
@@ -1352,16 +1412,26 @@ static int sort_line_children(struct libscols_line *ln, struct libscols_column *
 {
 	struct list_head *p;
 
-	if (list_empty(&ln->ln_branch))
-		return 0;
+	if (!list_empty(&ln->ln_branch)) {
+		list_for_each(p, &ln->ln_branch) {
+			struct libscols_line *chld =
+					list_entry(p, struct libscols_line, ln_children);
+			sort_line_children(chld, cl);
+		}
+
+		list_sort(&ln->ln_branch, cells_cmp_wrapper_children, cl);
+	}
+
+	if (is_first_group_member(ln)) {
+		list_for_each(p, &ln->group->gr_children) {
+			struct libscols_line *chld =
+					list_entry(p, struct libscols_line, ln_children);
+			sort_line_children(chld, cl);
+		}
 
-	list_for_each(p, &ln->ln_branch) {
-		struct libscols_line *chld =
-				list_entry(p, struct libscols_line, ln_children);
-		sort_line_children(chld, cl);
+		list_sort(&ln->group->gr_children, cells_cmp_wrapper_children, cl);
 	}
 
-	list_sort(&ln->ln_branch, cells_cmp_wrapper_children, cl);
 	return 0;
 }