Fix crash when long-pressing Send Report button on iPad

Closes #190

Tusker/Caching/DiskCache.swift

@@ -21,7 +21,7 @@ class DiskCache<T> {
     let defaultExpiry: CacheExpiry
     let transformer: DiskCacheTransformer<T>
     
-    private var fileStates = [String: FileState]()
+    private var fileStates = MultiThreadDictionary<String, FileState>()
     
     init(name: String, defaultExpiry: CacheExpiry, transformer: DiskCacheTransformer<T>, fileManager: FileManager = .default) throws {
         self.defaultExpiry = defaultExpiry
@@ -117,7 +117,9 @@ class DiskCache<T> {
     func removeAll() throws {
         try fileManager.removeItem(atPath: path)
         try createDirectory()
-        fileStates.removeAll()
+        fileStates.withLock { dict in
+            dict.removeAll()
+        }
     }
     
 }

Tusker/MultiThreadDictionary.swift

@@ -16,13 +16,7 @@ class MultiThreadDictionary<Key: Hashable & Sendable, Value: Sendable> {
     private let lock: LockHolder<[AnyHashable: Any]>
     
     init() {
-        if #available(iOS 16.0, *) {
-            let lock = OSAllocatedUnfairLock(initialState: [:])
-            self.lock = LockHolder(withLock: lock.withLock(_:))
-        } else {
-            let lock = UnfairLock(initialState: [:])
-            self.lock = LockHolder(withLock: lock.withLock(_:))
-        }
+        self.lock = LockHolder(initialState: [:])
     }
     
     subscript(key: Key) -> Value? {
@@ -66,6 +60,16 @@ class MultiThreadDictionary<Key: Hashable & Sendable, Value: Sendable> {
 // see #178
 fileprivate struct LockHolder<State> {
     let withLock: (_ body: @Sendable (inout State) throws -> any Sendable) throws -> any Sendable
+    
+    init(initialState: State) {
+        if #available(iOS 16.0, *) {
+            let lock = OSAllocatedUnfairLock(initialState: initialState)
+            self.withLock = lock.withLock(_:)
+        } else {
+            let lock = UnfairLock(initialState: initialState)
+            self.withLock = lock.withLock(_:)
+        }
+    }
 }
 
 // TODO: replace this only with OSAllocatedUnfairLock

Tusker/Screens/Crash Reporter/IssueReporterViewController.swift

@@ -142,6 +142,7 @@ class IssueReporterViewController: UIViewController {
         let url = dir.appendingPathComponent(reportFilename)
         try! reportText.data(using: .utf8)!.write(to: url)
         let activityController = UIActivityViewController(activityItems: [url], applicationActivities: nil)
+        activityController.popoverPresentationController?.sourceView = sendReportButton
         present(activityController, animated: true)
     }
 
@@ -154,7 +155,11 @@ class IssueReporterViewController: UIViewController {
 extension IssueReporterViewController: MFMailComposeViewControllerDelegate {
     func mailComposeController(_ controller: MFMailComposeViewController, didFinishWith result: MFMailComposeResult, error: Error?) {
         controller.dismiss(animated: true) {
-            self.dismiss()
+            if result == .cancelled {
+                // don't dismiss ourself, to allowe the user to send the report a different way
+            } else {
+                self.dismiss()
+            }
         }
     }
 }