From 35527bc52e9590836a930e1a49444d16cf738daa Mon Sep 17 00:00:00 2001
From: Tae Won Ha <h@taewon.de>
Date: Wed, 27 Dec 2023 21:50:10 +0100
Subject: [PATCH] Do not include font check for CTRuns when typesetting.

We have to clear the cache when changing the font (and other parameters
which may affect the typesetting).
---
 Commons/Sources/Commons/FifoCache.swift          |  5 +++++
 .../Sources/NvimView/AttributesRunDrawer.swift   |  6 +++++-
 NvimView/Sources/NvimView/Typesetter.swift       | 16 +++++++---------
 .../Support/MinimalNvimViewDemo/Document.swift   |  2 +-
 4 files changed, 18 insertions(+), 11 deletions(-)

diff --git a/Commons/Sources/Commons/FifoCache.swift b/Commons/Sources/Commons/FifoCache.swift
index 3cfa22ae..42fa9356 100644
--- a/Commons/Sources/Commons/FifoCache.swift
+++ b/Commons/Sources/Commons/FifoCache.swift
@@ -23,6 +23,11 @@ public final class FifoCache<Key: Hashable, Value> {
   }
 
   public func valueForKey(_ key: Key) -> Value? { self.storage[key] }
+  
+  public func clear() {
+    self.keys = Array(repeating: nil, count: count)
+    self.storage.removeAll(keepingCapacity: true)
+  }
 
   private let count: Int
   private var keys: [Key?]
diff --git a/NvimView/Sources/NvimView/AttributesRunDrawer.swift b/NvimView/Sources/NvimView/AttributesRunDrawer.swift
index 31b366f8..9ff0f22e 100644
--- a/NvimView/Sources/NvimView/AttributesRunDrawer.swift
+++ b/NvimView/Sources/NvimView/AttributesRunDrawer.swift
@@ -18,7 +18,9 @@ final class AttributesRunDrawer {
     didSet { self.updateFontMetrics() }
   }
 
-  var usesLigatures: Bool
+  var usesLigatures: Bool {
+    didSet { self.typesetter.clearCache() }
+  }
 
   private(set) var cellSize: CGSize = .zero
   private(set) var baselineOffset: CGFloat = 0
@@ -187,5 +189,7 @@ final class AttributesRunDrawer {
     self.descent = CTFontGetDescent(self.font)
     self.underlinePosition = CTFontGetUnderlinePosition(self.font)
     self.underlineThickness = CTFontGetUnderlineThickness(self.font)
+    
+    self.typesetter.clearCache()
   }
 }
diff --git a/NvimView/Sources/NvimView/Typesetter.swift b/NvimView/Sources/NvimView/Typesetter.swift
index 95abcbae..5a0e2526 100644
--- a/NvimView/Sources/NvimView/Typesetter.swift
+++ b/NvimView/Sources/NvimView/Typesetter.swift
@@ -8,6 +8,10 @@ import Commons
 import os
 
 final class Typesetter {
+  func clearCache() {
+    self.ctRunsCache.clear()
+  }
+  
   func fontGlyphRunsWithLigatures(
     nvimUtf16Cells: [[Unicode.UTF16.CodeUnit]],
     startColumn: Int,
@@ -141,8 +145,7 @@ final class Typesetter {
   }
 
   private func ctRuns(from utf16Chars: [Unicode.UTF16.CodeUnit], font: NSFont) -> [CTRun] {
-    if let ctRunsAndFont = self.ctRunsCache.valueForKey(utf16Chars),
-       font == ctRunsAndFont.font { return ctRunsAndFont.ctRuns }
+    if let ctRunsAndFont = self.ctRunsCache.valueForKey(utf16Chars) { return ctRunsAndFont }
 
     let attrStr = NSAttributedString(
       string: String(utf16CodeUnits: utf16Chars, count: utf16Chars.count),
@@ -152,7 +155,7 @@ final class Typesetter {
     let ctLine = CTLineCreateWithAttributedString(attrStr)
     guard let ctRuns = CTLineGetGlyphRuns(ctLine) as? [CTRun] else { return [] }
 
-    self.ctRunsCache.set(CtRunsAndFont(ctRuns: ctRuns, font: font), forKey: utf16Chars)
+    self.ctRunsCache.set(ctRuns, forKey: utf16Chars)
 
     return ctRuns
   }
@@ -270,15 +273,10 @@ final class Typesetter {
     }
   }
 
-  private let ctRunsCache = FifoCache<[Unicode.UTF16.CodeUnit], CtRunsAndFont>(count: 5000)
+  private let ctRunsCache = FifoCache<[Unicode.UTF16.CodeUnit], [CTRun]>(count: 5000)
 
   private let log = OSLog(subsystem: Defs.loggerSubsystem, category: Defs.LoggerCategory.view)
 
-  private struct CtRunsAndFont {
-    var ctRuns: [CTRun]
-    var font: NSFont
-  }
-
   private struct NvimUtf16CellsRun {
     var startColumn: Int
     var nvimUtf16Cells: [[Unicode.UTF16.CodeUnit]]
diff --git a/NvimView/Support/MinimalNvimViewDemo/Document.swift b/NvimView/Support/MinimalNvimViewDemo/Document.swift
index dc420f85..57efd1e3 100644
--- a/NvimView/Support/MinimalNvimViewDemo/Document.swift
+++ b/NvimView/Support/MinimalNvimViewDemo/Document.swift
@@ -16,7 +16,7 @@ class Document: NSDocument, NSWindowDelegate {
   override init() {
     super.init()
 
-    self.nvimView.font = NSFont(name: "Fira Code", size: 13)
+    self.nvimView.font = NSFont(name: "Iosevka", size: 13)
       ?? NSFont.userFixedPitchFont(ofSize: 13)!
     self.nvimView.usesLigatures = true
     self.nvimView.usesLiveResize = true