From d27bddb2caf9e22bb7adad065f356aba13d5e542 Mon Sep 17 00:00:00 2001
From: Shadowfacts <me@shadowfacts.net>
Date: Mon, 15 Jun 2020 22:34:42 -0400
Subject: [PATCH] Fix profile header image not showing up on first load

The issue occurred because the profile header would kick off a request
upon loading, then the profile table would request the initial set of
statuses shortly thereafter which would result in reloadData being called
which would cancel the request without removing the group, so the request
generated by the newly-reloaded header cell would attach a callback to
the cancelled request, resulting in the header image never displaying.
---
 Tusker/Caching/ImageCache.swift               | 30 +++++++++++--------
 .../Profile/ProfileTableViewController.swift  | 28 ++++++++---------
 2 files changed, 32 insertions(+), 26 deletions(-)

diff --git a/Tusker/Caching/ImageCache.swift b/Tusker/Caching/ImageCache.swift
index 2e04fbd9..7681ab6e 100644
--- a/Tusker/Caching/ImageCache.swift
+++ b/Tusker/Caching/ImageCache.swift
@@ -18,7 +18,7 @@ class ImageCache {
 
     let cache: Cache<Data>
     
-    var requests = [URL: RequestGroup]()
+    private var groups = [URL: RequestGroup]()
     
     init(name: String, memoryExpiry expiry: Expiry) {
         let storage = MemoryStorage<Data>(config: MemoryConfig(expiry: expiry))
@@ -43,14 +43,18 @@ class ImageCache {
             completion?(data)
             return nil
         } else {
-            if let completion = completion, let group = requests[url] {
+            if let completion = completion, let group = groups[url] {
                 return group.addCallback(completion)
             } else {
-                let group = RequestGroup(url: url)
-                let request = group.addCallback(completion)
-                group.run { (data) in
-                    try? self.cache.setObject(data, forKey: key)
+                let group = RequestGroup(url: url) { (data) in
+                    if let data = data {
+                        try? self.cache.setObject(data, forKey: key)
+                    }
+                    self.groups.removeValue(forKey: url)
                 }
+                groups[url] = group
+                let request = group.addCallback(completion)
+                group.run()
                 return request
             }
         }
@@ -61,29 +65,30 @@ class ImageCache {
     }
 
     func cancelWithoutCallback(_ url: URL) {
-        requests[url]?.cancelWithoutCallback()
+        groups[url]?.cancelWithoutCallback()
     }
     
-    class RequestGroup {
+    private class RequestGroup {
         let url: URL
+        private let onFinished: (Data?) -> Void
         private var task: URLSessionDataTask?
         private var requests = [Request]()
 
-        init(url: URL) {
+        init(url: URL, onFinished: @escaping (Data?) -> Void) {
             self.url = url
+            self.onFinished = onFinished
         }
 
         deinit {
             task?.cancel()
         }
         
-        func run(cache: @escaping (Data) -> Void) {
+        func run() {
             task = URLSession.shared.dataTask(with: url, completionHandler: { (data, response, error) in
                 guard error == nil, let data = data else {
                     self.complete(with: nil)
                     return
                 }
-                cache(data)
                 self.complete(with: data)
             })
             task!.resume()
@@ -123,11 +128,12 @@ class ImageCache {
                     callback(data)
                 }
             }
+            self.onFinished(data)
         }
     }
     
     class Request {
-        weak var group: RequestGroup?
+        private weak var group: RequestGroup?
         private(set) var callback: ((Data?) -> Void)?
         private(set) var cancelled: Bool = false
         
diff --git a/Tusker/Screens/Profile/ProfileTableViewController.swift b/Tusker/Screens/Profile/ProfileTableViewController.swift
index ec85650c..c1dd5c61 100644
--- a/Tusker/Screens/Profile/ProfileTableViewController.swift
+++ b/Tusker/Screens/Profile/ProfileTableViewController.swift
@@ -16,20 +16,8 @@ class ProfileTableViewController: EnhancedTableViewController {
     
     var accountID: String!
     
-    var pinnedStatuses: [(id: String, state: StatusState)] = [] {
-        didSet {
-            DispatchQueue.main.async {
-                self.tableView.reloadData()
-            }
-        }
-    }
-    var timelineSegments: [[(id: String, state: StatusState)]] = [] {
-        didSet {
-            DispatchQueue.main.async {
-                self.tableView.reloadData()
-            }
-        }
-    }
+    var pinnedStatuses: [(id: String, state: StatusState)] = []
+    var timelineSegments: [[(id: String, state: StatusState)]] = []
     
     var older: RequestRange?
     var newer: RequestRange?
@@ -124,6 +112,12 @@ class ProfileTableViewController: EnhancedTableViewController {
             
             self.mastodonController.persistentContainer.addAll(statuses: statuses) {
                 self.pinnedStatuses = statuses.map { ($0.id, .unknown) }
+                let indexPaths = (0..<statuses.count).map { IndexPath(row: $0, section: 1) }
+                DispatchQueue.main.async {
+                    UIView.performWithoutAnimation {
+                        self.tableView.insertRows(at: indexPaths, with: .none)
+                    }
+                }
             }
         }
         
@@ -135,6 +129,12 @@ class ProfileTableViewController: EnhancedTableViewController {
     
                 self.older = pagination?.older
                 self.newer = pagination?.newer
+                
+                DispatchQueue.main.async {
+                    UIView.performWithoutAnimation {
+                        self.tableView.insertSections(IndexSet(integer: 2), with: .none)
+                    }
+                }
             }
         }
     }