Speed up AllPagesViewController render time

Profiling revealed that rendering AllPagesViewController spent
a substantial amount of time in FileManager's attributesOfItem. Using
a Yap view instead results in a significant speed-up.

Kiwi/Wiki/Indexer.swift

@@ -73,6 +73,20 @@ class Indexer {
         })
     }
 
+    func list() -> [String] {
+        var results: [String] = []
+
+        self.backingStore.newConnection().read({ (transaction) in
+            if let tx = transaction.ext("orderdedByModifiedTimeDesc") as? YapDatabaseViewTransaction {
+                tx.enumerateKeys(inGroup: "pages") { (collection, key, index, stop) in
+                    results.append(key)
+                }
+            }
+        })
+
+        return results
+    }
+
     func get(permalink: String) -> Page? {
         var page: Page?
 

Kiwi/Wiki/Wiki.swift

@@ -92,18 +92,7 @@ class Wiki {
     }
 
     func files() -> [String] {
-        let files = self.filesystem.list(path: Wiki.WIKI_PATH)
-        return files.filter({ (path: Path) -> Bool in
-            return !path.isDirectory
-        }).sorted(by: { (path1, path2) -> Bool in
-            if path1.modificationDate == nil || path2.modificationDate == nil {
-                return true
-            } else {
-                return path1.modificationDate! > path2.modificationDate!
-            }
-        }).map({ (path: Path) -> String in
-            return path.fileName
-        })
+        return self.indexer.list()
     }
 
     static func isPage(_ permalink: String) -> Bool {

Kiwi/Wiki/YapDatabase.swift

@@ -36,8 +36,28 @@ class Yap {
             )
 
             _sharedInstance?.register(fullTextSearch, withName: "fts")
+            _sharedInstance?.register(orderedByModifiedTimeView(), withName: "orderdedByModifiedTimeDesc")
         }
 
         return _sharedInstance!
     }
+
+    class func orderedByModifiedTimeView() -> YapDatabaseView {
+        let grouping = YapDatabaseViewGrouping.withKeyBlock { (transaction, collection, key) -> String? in
+            return collection
+        }
+        let sorting = YapDatabaseViewSorting.withObjectBlock { (transaction, group, collection1, key1, object1, collection2, key2, object2) -> ComparisonResult in
+            let page1 = (object1 as! EncodablePage).page
+            let page2 = (object2 as! EncodablePage).page
+            if page1.modifiedTime > page2.modifiedTime {
+                return .orderedAscending
+            } else if page2.modifiedTime < page2.modifiedTime {
+                return .orderedDescending
+            } else {
+                return .orderedSame
+            }
+        }
+        let versionTag = "2019-11-25"
+        return YapDatabaseAutoView(grouping: grouping, sorting: sorting, versionTag: versionTag)
+    }
 }

KiwiTests/IndexerSpec.swift

@@ -56,18 +56,39 @@ class FakeFilesystem: EventedFilesystem {
 }
 
 class IndexerSpec: QuickSpec {
-
     override func spec() {
         describe("the Indexer") {
             var indexer: Indexer!
-            var page: Page!
             var filesystem: FakeFilesystem!
+            var page1: Page!
+            var page2: Page!
+
+            func toDate(str: String) -> Date {
+                let dateFormatter = DateFormatter()
+                dateFormatter.dateFormat = "yyyy'-'MM'-'dd"
+                return dateFormatter.date(from: str)!
+            }
 
             beforeEach {
                 filesystem = FakeFilesystem()
                 indexer = Indexer(filesystem: filesystem)
                 indexer.start()
-                page = Page(rawContent: "test", permalink: "test_page", name: "Test", modifiedTime: Date(), createdTime: Date(), isDirty: false)
+                page1 = Page(
+                    rawContent: "test",
+                    permalink: "test_page",
+                    name: "Test",
+                    modifiedTime: toDate(str: "2019-11-01"),
+                    createdTime: toDate(str: "2019-11-01"),
+                    isDirty: false
+                )
+                page2 = Page(
+                    rawContent: "test2",
+                    permalink: "test_page2",
+                    name: "Test2",
+                    modifiedTime: toDate(str: "2019-11-02"),
+                    createdTime: toDate(str: "2019-11-02"),
+                    isDirty: false
+                )
             }
 
             context("when a page is written to the filesystem") {
@@ -82,7 +103,7 @@ class IndexerSpec: QuickSpec {
 
             context("when a page is indexed") {
                 beforeEach {
-                    indexer.index(page: page)
+                    indexer.index(page: page1)
                 }
 
                 context("when a file is removed from the filesystem") {
@@ -95,6 +116,18 @@ class IndexerSpec: QuickSpec {
                     }
                 }
             }
+
+            describe(".list") {
+                beforeEach {
+                    indexer.index(page: page1)
+                    indexer.index(page: page2)
+                }
+
+                it("returns all permalinks in descending order") {
+                    let permalinks = indexer.list()
+                    expect(permalinks).to(equal([page2.permalink, page1.permalink]))
+                }
+            }
         }
     }
 }