Add --max-distance for recursive link filtering options

adapter/sqlite/note_dao.go

@@ -342,7 +342,7 @@ func (d *NoteDAO) findRows(opts note.FinderOpts) (*sql.Rows, error) {
 	groupById := false
 	args := make([]interface{}, 0)
 
-	setupLinkFilter := func(paths []string, forward, negate bool, recursive bool) error {
+	setupLinkFilter := func(paths []string, forward, negate, recursive bool, maxDistance int) error {
 		ids, err := d.findIdsByPathPrefixes(paths)
 		if err != nil {
 			return err
@@ -371,7 +371,12 @@ func (d *NoteDAO) findRows(opts note.FinderOpts) (*sql.Rows, error) {
 			// Credit to https://inviqa.com/blog/storing-graphs-database-sql-meets-social-network
 			links_src = "links_transitive_closure"
 			orderTerms = append(orderTerms, alias+".distance")
-			cteClauses = append(cteClauses, `WITH RECURSIVE links_transitive_closure(source_id, target_id, title, snippet, distance, path) AS (
+
+			if maxDistance == 0 {
+				maxDistance = 1000
+			}
+
+			cteClauses = append(cteClauses, fmt.Sprintf(`WITH RECURSIVE links_transitive_closure(source_id, target_id, title, snippet, distance, path) AS (
     SELECT source_id, target_id, title, snippet,
 	       1 AS distance,
            source_id || '.' || target_id || '.' AS path
@@ -385,8 +390,8 @@ func (d *NoteDAO) findRows(opts note.FinderOpts) (*sql.Rows, error) {
       FROM links AS l
       JOIN links_transitive_closure AS tc
         ON l.source_id = tc.target_id
-     WHERE tc.path NOT LIKE '%' || l.target_id || '.%'
-)`)
+     WHERE tc.distance < %d AND tc.path NOT LIKE '%%' || l.target_id || '.%%'
+)`, maxDistance))
 		}
 
 		if !negate {
@@ -439,13 +444,13 @@ func (d *NoteDAO) findRows(opts note.FinderOpts) (*sql.Rows, error) {
 			whereExprs = append(whereExprs, strings.Join(globs, " AND "))
 
 		case note.LinkedByFilter:
-			err := setupLinkFilter(filter.Paths, false, filter.Negate, filter.Recursive)
+			err := setupLinkFilter(filter.Paths, false, filter.Negate, filter.Recursive, filter.MaxDistance)
 			if err != nil {
 				return nil, err
 			}
 
 		case note.LinkingToFilter:
-			err := setupLinkFilter(filter.Paths, true, filter.Negate, filter.Recursive)
+			err := setupLinkFilter(filter.Paths, true, filter.Negate, filter.Recursive, filter.MaxDistance)
 			if err != nil {
 				return nil, err
 			}

adapter/sqlite/note_dao_test.go

@@ -528,6 +528,20 @@ func TestNoteDAOFindLinkedByRecursive(t *testing.T) {
 	)
 }
 
+func TestNoteDAOFindLinkedByRecursiveWithMaxDistance(t *testing.T) {
+	testNoteDAOFindPaths(t,
+		note.FinderOpts{
+			Filters: []note.Filter{note.LinkedByFilter{
+				Paths:       []string{"log/2021-01-04.md"},
+				Negate:      false,
+				Recursive:   true,
+				MaxDistance: 2,
+			}},
+		},
+		[]string{"index.md", "f39c8.md"},
+	)
+}
+
 func TestNoteDAOFindLinkedByWithSnippets(t *testing.T) {
 	testNoteDAOFind(t,
 		note.FinderOpts{
@@ -612,6 +626,20 @@ func TestNoteDAOFindLinkingToRecursive(t *testing.T) {
 	)
 }
 
+func TestNoteDAOFindLinkingToRecursiveWithMaxDistance(t *testing.T) {
+	testNoteDAOFindPaths(t,
+		note.FinderOpts{
+			Filters: []note.Filter{note.LinkingToFilter{
+				Paths:       []string{"log/2021-01-04.md"},
+				Negate:      false,
+				Recursive:   true,
+				MaxDistance: 2,
+			}},
+		},
+		[]string{"log/2021-01-03.md", "f39c8.md"},
+	)
+}
+
 func TestNoteDAOFindNotLinkingTo(t *testing.T) {
 	testNoteDAOFindPaths(t,
 		note.FinderOpts{

cmd/finder_opts.go

@@ -24,6 +24,7 @@ type Filtering struct {
 	LinkingTo      []string `help:"Only the notes linking to the given notes" placeholder:"<path>" short:"L"`
 	NotLinkedBy    []string `help:"Only the notes not linked by the given notes" placeholder:"<path>"`
 	NotLinkingTo   []string `help:"Only the notes not linking to the given notes" placeholder:"<path>"`
+	MaxDistance    int      `help:"Maximum distance between two linked notes"`
 	Orphan         bool     `help:"Only the notes which don't have any other note linking to them"`
 	Exclude        []string `help:"Excludes notes matching the given file path pattern from the list" short:"x" placeholder:"<glob>"`
 	Recursive      bool     `help:"Follow links recursively" short:"r"`
@@ -128,18 +129,20 @@ func NewFinderOpts(zk *zk.Zk, filtering Filtering, sorting Sorting) (*note.Finde
 	linkedByPaths, ok := relPaths(zk, filtering.LinkedBy)
 	if ok {
 		filters = append(filters, note.LinkedByFilter{
-			Paths:     linkedByPaths,
-			Negate:    false,
-			Recursive: filtering.Recursive,
+			Paths:       linkedByPaths,
+			Negate:      false,
+			Recursive:   filtering.Recursive,
+			MaxDistance: filtering.MaxDistance,
 		})
 	}
 
 	linkingToPaths, ok := relPaths(zk, filtering.LinkingTo)
 	if ok {
 		filters = append(filters, note.LinkingToFilter{
-			Paths:     linkingToPaths,
-			Negate:    false,
-			Recursive: filtering.Recursive,
+			Paths:       linkingToPaths,
+			Negate:      false,
+			Recursive:   filtering.Recursive,
+			MaxDistance: filtering.MaxDistance,
 		})
 	}
 

core/note/find.go

@@ -42,16 +42,18 @@ type ExcludePathFilter []string
 
 // LinkedByFilter is a note filter used to select notes being linked by another one.
 type LinkedByFilter struct {
-	Paths     []string
-	Negate    bool
-	Recursive bool
+	Paths       []string
+	Negate      bool
+	Recursive   bool
+	MaxDistance int
 }
 
 // LinkingToFilter is a note filter used to select notes being linked by another one.
 type LinkingToFilter struct {
-	Paths     []string
-	Negate    bool
-	Recursive bool
+	Paths       []string
+	Negate      bool
+	Recursive   bool
+	MaxDistance int
 }
 
 // OrphanFilter is a note filter used to select notes having no other notes linking to them.