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>

3 files changed, 195 insertions, 1 deletions

diff --git a/libsmartcols/src/Makemodule.am b/libsmartcols/src/Makemodule.am
index c458715f5..fff314c73 100644
--- a/libsmartcols/src/Makemodule.am
+++ b/libsmartcols/src/Makemodule.am
@@ -22,6 +22,7 @@ libsmartcols_la_SOURCES= \
 	libsmartcols/src/buffer.c \
 	libsmartcols/src/calculate.c \
 	libsmartcols/src/grouping.c \
+	libsmartcols/src/walk.c \
 	libsmartcols/src/init.c
 
 libsmartcols_la_LIBADD = $(LDADD) libcommon.la
diff --git a/libsmartcols/src/smartcolsP.h b/libsmartcols/src/smartcolsP.h
index 543588b10..3653eda07 100644
--- a/libsmartcols/src/smartcolsP.h
+++ b/libsmartcols/src/smartcolsP.h
@@ -217,7 +217,9 @@ struct libscols_table {
 	struct list_head	tb_groups;	/* all defined groups */
 	struct libscols_group	**grpset;
 	size_t			grpset_size;
+
 	size_t			ngrpchlds_pending;	/* groups with not yet printed children */
+	struct libscols_line	*walk_last_tree_root;	/* last root, used by scols_walk_() */
 
 	struct libscols_symbols	*symbols;
 	struct libscols_cell	title;		/* optional table title (for humans) */
@@ -239,6 +241,7 @@ struct libscols_table {
 			header_repeat   :1,     /* print header after libscols_table->termheight */
 			header_printed  :1,	/* header already printed */
 			priv_symbols	:1,	/* default private symbols */
+			walk_last_done	:1,	/* last tree root walked */
 			no_headings	:1,	/* don't print header */
 			no_encode	:1,	/* don't care about control and non-printable chars */
 			no_linesep	:1,	/* don't print line separator */
@@ -318,6 +321,18 @@ void scols_groups_reset_state(struct libscols_table *tb);
 struct libscols_group *scols_grpset_get_printable_children(struct libscols_table *tb);
 
 /*
+ * walk.c
+ */
+extern 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);
+extern int scols_walk_is_last(struct libscols_table *tb, struct libscols_line *ln);
+
+/*
  * calculate.c
  */
 extern int __scols_calculate(struct libscols_table *tb, struct libscols_buffer *buf);
@@ -352,14 +367,40 @@ extern void fput_children_close(struct libscols_table *tb);
 extern void fput_line_open(struct libscols_table *tb);
 extern void fput_line_close(struct libscols_table *tb, int last, int last_in_table);
 
+static inline int is_tree_root(struct libscols_line *ln)
+{
+	return ln && !ln->parent && !ln->parent_group;
+}
+
+static inline int is_last_tree_root(struct libscols_table *tb, struct libscols_line *ln)
+{
+	if (!ln || !tb || tb->walk_last_tree_root != ln)
+		return 0;
+
+	return 1;
+}
+
+static inline int is_child(struct libscols_line *ln)
+{
+	return ln && ln->parent;
+}
+
 static inline int is_last_child(struct libscols_line *ln)
 {
 	if (!ln || !ln->parent)
-		return 1;
+		return 0;
 
 	return list_entry_is_last(&ln->ln_children, &ln->parent->ln_branch);
 }
 
+static inline int is_first_child(struct libscols_line *ln)
+{
+	if (!ln || !ln->parent)
+		return 0;
+
+	return list_entry_is_first(&ln->ln_children, &ln->parent->ln_branch);
+}
+
 
 static inline int is_last_column(struct libscols_column *cl)
 {
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;
+}