Add Clear Image Cache option to Advanced prefs

Tusker/Caching/Cache.swift

@@ -47,4 +47,15 @@ enum Cache<T> {
             try hybrid.setObject(object, forKey: key, expiry: expiry)
         }
     }
+    
+    func removeAll() throws {
+        switch self {
+        case let .memory(memory):
+            memory.removeAll()
+        case let .disk(disk):
+            try disk.removeAll()
+        case let .hybrid(hybrid):
+            try hybrid.removeAll()
+        }
+    }
 }

Tusker/Caching/ImageCache.swift

@@ -16,7 +16,7 @@ class ImageCache {
     static let attachments = ImageCache(name: "Attachments", memoryExpiry: .seconds(60 * 2))
     static let emojis = ImageCache(name: "Emojis", memoryExpiry: .seconds(60 * 5), diskExpiry: .seconds(60 * 60))
 
-    let cache: Cache<Data>
+    private let cache: Cache<Data>
     
     private var groups = [URL: RequestGroup]()
     
@@ -68,6 +68,10 @@ class ImageCache {
         groups[url]?.cancelWithoutCallback()
     }
     
+    func reset() throws {
+        try cache.removeAll()
+    }
+    
     private class RequestGroup {
         let url: URL
         private let onFinished: (Data?) -> Void

Tusker/Screens/Preferences/AdvancedPrefsView.swift

@@ -46,12 +46,15 @@ struct AdvancedPrefsView : View {
     var cachingSection: some View {
         Section(header: Text("Caching")) {
             Button(action: clearCache) {
-                Text("Clear Cache")
+                Text("Clear Mastodon Cache")
+            }.foregroundColor(.red)
+            Button(action: clearImageCaches) {
+                Text("Clear Image Caches")
             }.foregroundColor(.red)
         }
     }
     
-    func clearCache() {
+    private func clearCache() {
         for account in LocalData.shared.accounts {
             let controller = MastodonController.getForAccount(account)
             let coordinator = controller.persistentContainer.persistentStoreCoordinator
@@ -59,7 +62,22 @@ struct AdvancedPrefsView : View {
                 try! coordinator.destroyPersistentStore(at: store.url!, ofType: store.type, options: store.options)
             }
         }
-        MastodonController.resetAll()
+        resetUI()
+    }
+    
+    private func clearImageCaches() {
+        [
+            ImageCache.avatars,
+            ImageCache.headers,
+            ImageCache.attachments,
+            ImageCache.emojis,
+        ].forEach {
+            try! $0.reset()
+        }
+        resetUI()
+    }
+    
+    private func resetUI() {
         let mostRecent = LocalData.shared.getMostRecentAccount()!
         NotificationCenter.default.post(name: .activateAccount, object: nil, userInfo: ["account": mostRecent])
     }