libsmartcols: add generic function to walk on tree

Now we implement the same thing on more places. Let's add one set of
functions to walk the tree and use it everywhere.

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

1 files changed, 152 insertions, 0 deletions

diff --git a/libsmartcols/src/walk.c b/libsmartcols/src/walk.c
new file mode 100644
index 000000000..a75fde6a3
--- /dev/null
+++ b/libsmartcols/src/walk.c
@@ -0,0 +1,152 @@
+#include "smartcolsP.h"
+
+static int walk_line(struct libscols_table *tb,
+		     struct libscols_line *ln,
+		     struct libscols_column *cl,
+		     int (*callback)(struct libscols_table *,
+			            struct libscols_line *,
+				    struct libscols_column *,
+				    void *),
+		    void *data)
+{
+	int rc = 0;
+
+	DBG(LINE, ul_debugobj(ln, " wall line"));
+
+	/* we list group children in __scols_print_tree() after tree root node */
+	if (is_group_member(ln) && is_last_group_member(ln) && has_group_children(ln))
+		tb->ngrpchlds_pending++;
+
+	if (has_groups(tb))
+		rc = scols_groups_update_grpset(tb, ln);
+	if (rc == 0)
+		rc = callback(tb, ln, cl, data);
+
+	/* children */
+	if (rc == 0 && has_children(ln)) {
+		struct list_head *p;
+
+		DBG(LINE, ul_debugobj(ln, " children walk"));
+
+		list_for_each(p, &ln->ln_branch) {
+			struct libscols_line *chld = list_entry(p,
+					struct libscols_line, ln_children);
+
+			rc = walk_line(tb, chld, cl, callback, data);
+			if (rc)
+				break;
+		}
+	}
+
+	DBG(LINE, ul_debugobj(ln, "<- walk line done [rc=%d]", rc));
+	return rc;
+}
+
+/* last line in the tree? */
+int scols_walk_is_last(struct libscols_table *tb, struct libscols_line *ln)
+{
+	if (tb->walk_last_done == 0)
+		return 0;
+	if (tb->ngrpchlds_pending > 0)
+		return 0;
+	if (has_children(ln))
+		return 0;
+	if (is_tree_root(ln) && !is_last_tree_root(tb, ln))
+		return 0;
+	if (is_group_member(ln) && (!is_last_group_member(ln) || has_group_children(ln)))
+		return 0;
+	if (is_child(ln)) {
+		struct libscols_line *parent = ln->parent;
+
+		if (!is_last_child(ln))
+			return 0;
+		while (parent) {
+			if (is_child(parent) && !is_last_child(parent))
+				return 0;
+			if (!parent->parent)
+				break;
+			parent = parent->parent;
+		}
+		if (is_tree_root(parent) && !is_last_tree_root(tb, parent))
+			return 0;
+	}
+	if (is_group_child(ln) && !is_last_group_child(ln))
+		return 0;
+
+	DBG(LINE, ul_debugobj(ln, "last in table"));
+	return 1;
+}
+
+int scols_walk_tree(struct libscols_table *tb,
+		    struct libscols_column *cl,
+		    int (*callback)(struct libscols_table *,
+			            struct libscols_line *,
+				    struct libscols_column *,
+				    void *),
+		    void *data)
+{
+	int rc = 0;
+	struct libscols_line *ln;
+	struct libscols_iter itr;
+
+	assert(tb);
+	DBG(TAB, ul_debugobj(tb, ">> walk start"));
+
+	/* init */
+	tb->ngrpchlds_pending = 0;
+	tb->walk_last_tree_root = NULL;
+	tb->walk_last_done = 0;
+
+	if (has_groups(tb))
+		scols_groups_reset_state(tb);
+
+	/* set pointer to last tree root */
+	scols_reset_iter(&itr, SCOLS_ITER_FORWARD);
+	while (scols_table_next_line(tb, &itr, &ln) == 0) {
+		if (!tb->walk_last_tree_root)
+			tb->walk_last_tree_root = ln;
+		if (is_child(ln) || is_group_child(ln))
+			continue;
+		tb->walk_last_tree_root = ln;
+	}
+
+	/* walk */
+	scols_reset_iter(&itr, SCOLS_ITER_FORWARD);
+	while (rc == 0 && scols_table_next_line(tb, &itr, &ln) == 0) {
+		if (ln->parent || ln->parent_group)
+			continue;
+
+		if (tb->walk_last_tree_root == ln)
+			tb->walk_last_done = 1;
+		rc = walk_line(tb, ln, cl, callback, data);
+
+		/* walk group's children */
+		while (rc == 0 && tb->ngrpchlds_pending) {
+			struct libscols_group *gr = scols_grpset_get_printable_children(tb);
+			struct list_head *p;
+
+			DBG(LINE, ul_debugobj(ln, " walk group children [pending=%zu]", tb->ngrpchlds_pending));
+			if (!gr) {
+				DBG(LINE, ul_debugobj(ln, " *** ngrpchlds_pending counter invalid"));
+				tb->ngrpchlds_pending = 0;
+				break;
+			}
+
+			tb->ngrpchlds_pending--;
+
+			list_for_each(p, &gr->gr_children) {
+				struct libscols_line *chld =
+					list_entry(p, struct libscols_line, ln_children);
+
+				rc = walk_line(tb, chld, cl, callback, data);
+				if (rc)
+					break;
+			}
+		}
+	}
+
+	tb->ngrpchlds_pending = 0;
+	tb->walk_last_done = 0;
+	DBG(TAB, ul_debugobj(tb, "<< walk end [rc=%d]", rc));
+	return rc;
+}