From a4ab42da8a5c9a5dcada28c9423211c4f73d1ec4 Mon Sep 17 00:00:00 2001
From: Cameron Fischer <fischer.cameron@gmail.com>
Date: Mon, 21 Feb 2022 10:07:30 -0500
Subject: [PATCH] findListingsOfTiddler should cache results (#6327)

* findListingsOfTiddler uses FieldIndexer now

* Turns out FieldIndexer can't help listed[]
---
 core/modules/wiki.js                         | 25 ++++++++++++++------
 editions/test/tiddlers/tests/test-filters.js |  5 ++++
 2 files changed, 23 insertions(+), 7 deletions(-)

diff --git a/core/modules/wiki.js b/core/modules/wiki.js
index 99abe6b47..23d0c0d26 100755
--- a/core/modules/wiki.js
+++ b/core/modules/wiki.js
@@ -639,14 +639,25 @@ Lookup a given tiddler and return a list of all the tiddlers that include it in
 */
 exports.findListingsOfTiddler = function(targetTitle,fieldName) {
 	fieldName = fieldName || "list";
-	var titles = [];
-	this.each(function(tiddler,title) {
-		var list = $tw.utils.parseStringArray(tiddler.fields[fieldName]);
-		if(list && list.indexOf(targetTitle) !== -1) {
-			titles.push(title);
-		}
+	var wiki = this;
+	var listings = this.getGlobalCache("listings-" + fieldName,function() {
+		var listings = Object.create(null);
+		wiki.each(function(tiddler,title) {
+			var list = $tw.utils.parseStringArray(tiddler.fields[fieldName]);
+			if(list) {
+				for(var i = 0; i < list.length; i++) {
+					var listItem = list[i],
+						listing = listings[listItem] || [];
+					if (listing.indexOf(title) === -1) {
+						listing.push(title);
+					}
+					listings[listItem] = listing;
+				}
+			}
+		});
+		return listings;
 	});
-	return titles;
+	return listings[targetTitle] || [];
 };
 
 /*
diff --git a/editions/test/tiddlers/tests/test-filters.js b/editions/test/tiddlers/tests/test-filters.js
index 12d372a5b..2115e4d7d 100644
--- a/editions/test/tiddlers/tests/test-filters.js
+++ b/editions/test/tiddlers/tests/test-filters.js
@@ -395,6 +395,11 @@ Tests the filtering mechanism.
 			expect(wiki.filterTiddlers("[list[TiddlerSeventh]sort[title]]").join(",")).toBe("a fourth tiddler,MissingTiddler,Tiddler Three,TiddlerOne");
 			expect(wiki.filterTiddlers("[tag[one]list[TiddlerSeventh]sort[title]]").join(",")).toBe("a fourth tiddler,MissingTiddler,Tiddler Three,TiddlerOne");
 		});
+
+		it("should handle the listed operator", function() {
+			expect(wiki.filterTiddlers("TiddlerOne MissingTiddler +[listed[]]").join(",")).toBe('one,hasList');
+			expect(wiki.filterTiddlers("one two +[listed[tags]]").join(",")).toBe('TiddlerOne,$:/TiddlerTwo,Tiddler Three');
+		});
 	
 		it("should handle the next operator", function() {
 			expect(wiki.filterTiddlers("[[Tiddler Three]next[TiddlerSeventh]]").join(",")).toBe("a fourth tiddler");