Properly fix deadlocking when trying to access current capabilities

Package.swift

@@ -19,7 +19,7 @@ let package = Package(
     dependencies: [
         .package(
             url: "https://github.com/claucambra/NextcloudCapabilitiesKit.git",
-                .upToNextMajor(from: "2.1.2")
+                .upToNextMajor(from: "2.3.0")
         ),
         .package(url: "https://github.com/nextcloud/NextcloudKit", from: "5.0.4"),
         .package(url: "https://github.com/realm/realm-swift.git", exact: "20.0.1"),

Sources/NextcloudFileProviderKit/Enumeration/Enumerator+SyncEngine.swift

@@ -31,7 +31,10 @@ extension Enumerator {
     ) {
         let results = await self.scanRecursively(
             Item.rootContainer(
-                account: account, remoteInterface: remoteInterface, dbManager: dbManager
+                account: account,
+                remoteInterface: remoteInterface,
+                dbManager: dbManager,
+                remoteSupportsTrash: await remoteInterface.supportsTrash(account: account)
             ).metadata,
             account: account,
             remoteInterface: remoteInterface,

Sources/NextcloudFileProviderKit/Enumeration/Enumerator+Trash.swift

@@ -48,7 +48,7 @@ extension Enumerator {
         remoteInterface: RemoteInterface,
         dbManager: FilesDatabaseManager,
         trashItems: [NKTrash]
-    ) {
+    ) async {
         var newTrashedItems = [NSFileProviderItem]()
 
         // NKTrash items do not have an etag ; we assume they cannot be modified while they are in
@@ -71,7 +71,8 @@ extension Enumerator {
                 parentItemIdentifier: .trashContainer,
                 account: account,
                 remoteInterface: remoteInterface,
-                dbManager: dbManager
+                dbManager: dbManager,
+                remoteSupportsTrash: await remoteInterface.supportsTrash(account: account)
             )
             newTrashedItems.append(item)
 

Sources/NextcloudFileProviderKit/Enumeration/Enumerator.swift

@@ -451,7 +451,7 @@ public class Enumerator: NSObject, NSFileProviderEnumerator {
                     return
                 }
 
-                Self.completeChangesObserver(
+                await Self.completeChangesObserver(
                     observer,
                     anchor: anchor,
                     account: account,

Sources/NextcloudFileProviderKit/Interface/NextcloudKit+RemoteInterface.swift

@@ -12,24 +12,6 @@ import NextcloudCapabilitiesKit
 import NextcloudKit
 import OSLog
 
-fileprivate let CapabilitiesFetchInterval: TimeInterval = 30 * 60 // 30mins
-
-actor RetrievedCapabilitiesActor {
-    static let shared: RetrievedCapabilitiesActor = {
-        let instance = RetrievedCapabilitiesActor()
-        return instance
-    }()
-    var data: [String: (capabilities: Capabilities, retrievedAt: Date)] = [:]
-
-    func setCapabilities(
-        forAccount account: String,
-        capabilities: Capabilities,
-        retrievedAt: Date = Date()
-    ) async {
-        self.data[account] = (capabilities: capabilities, retrievedAt: retrievedAt)
-    }
-}
-
 extension NextcloudKit: RemoteInterface {
 
     public func setDelegate(_ delegate: any NextcloudKitDelegate) {
@@ -398,6 +380,10 @@ extension NextcloudKit: RemoteInterface {
         options: NKRequestOptions = .init(),
         taskHandler: @escaping (_ task: URLSessionTask) -> Void = { _ in }
     ) async -> (account: String, capabilities: Capabilities?, data: Data?, error: NKError) {
+        let ncKitAccount = account.ncKitAccount
+        await RetrievedCapabilitiesActor.shared.setOngoingFetch(
+            forAccount: ncKitAccount, ongoing: true
+        )
         let result = await withCheckedContinuation { continuation in
             getCapabilities(account: account.ncKitAccount, options: options, taskHandler: taskHandler) { account, data, error in
                 let capabilities: Capabilities? = {
@@ -407,6 +393,9 @@ extension NextcloudKit: RemoteInterface {
                 continuation.resume(returning: (account, capabilities, data?.data, error))
             }
         }
+        await RetrievedCapabilitiesActor.shared.setOngoingFetch(
+            forAccount: ncKitAccount, ongoing: false
+        )
         if let capabilities = result.1 {
             await RetrievedCapabilitiesActor.shared.setCapabilities(
                 forAccount: account.ncKitAccount, capabilities: capabilities
@@ -415,39 +404,6 @@ extension NextcloudKit: RemoteInterface {
         return result
     }
 
-    public func currentCapabilities(
-        account: Account,
-        options: NKRequestOptions = .init(),
-        taskHandler: @escaping (_ task: URLSessionTask) -> Void = { _ in }
-    ) async -> (account: String, capabilities: Capabilities?, data: Data?, error: NKError) {
-        let ncKitAccount = account.ncKitAccount
-        guard let lastRetrieval = await RetrievedCapabilitiesActor.shared.data[ncKitAccount],
-              lastRetrieval.retrievedAt.timeIntervalSince(Date()) > -CapabilitiesFetchInterval
-        else {
-            return await fetchCapabilities(
-                account: account, options: options, taskHandler: taskHandler
-            )
-        }
-        return (account.ncKitAccount, lastRetrieval.capabilities, nil, .success)
-    }
-
-    public func currentCapabilitiesSync(account: Account) -> Capabilities? {
-        let semaphore = DispatchSemaphore(value: 0)
-        var capabilities: Capabilities?
-        Task {
-            let (_, fetchedCapabilities, _, error) = await currentCapabilities(account: account)
-            if error != .success {
-                Logger
-                    .init(subsystem: Logger.subsystem, category: "NextcloudKitRemoteInterface")
-                    .error("Error during sync capabilities fetch: \(error.errorDescription, privacy: .public)")
-            }
-            capabilities = fetchedCapabilities
-            semaphore.signal()
-        }
-        semaphore.wait()
-        return capabilities
-    }
-
     public func fetchUserProfile(
         account: Account,
         options: NKRequestOptions = .init(),

Sources/NextcloudFileProviderKit/Interface/RemoteInterface.swift

@@ -10,6 +10,8 @@ import FileProvider
 import Foundation
 import NextcloudCapabilitiesKit
 import NextcloudKit
+import OSLog
+
 
 public enum EnumerateDepth: String {
     case target = "0"
@@ -157,16 +159,6 @@ public protocol RemoteInterface {
         taskHandler: @escaping (_ task: URLSessionTask) -> Void
     ) async -> (account: String, capabilities: Capabilities?, data: Data?, error: NKError)
 
-    // This method should result in fetches only after a certain period of time.
-    // Alternatively, it should only fetch when capabilities are guaranteed to have changed.
-    func currentCapabilities(
-        account: Account,
-        options: NKRequestOptions,
-        taskHandler: @escaping (_ task: URLSessionTask) -> Void
-    ) async -> (account: String, capabilities: Capabilities?, data: Data?, error: NKError)
-
-    func currentCapabilitiesSync(account: Account) -> Capabilities?
-
     func fetchUserProfile(
         account: Account,
         options: NKRequestOptions,
@@ -179,3 +171,44 @@ public protocol RemoteInterface {
         taskHandler: @escaping (_ task: URLSessionTask) -> Void
     ) async -> AuthenticationAttemptResultState
 }
+
+public extension RemoteInterface {
+
+    private var logger: Logger {
+        Logger(subsystem: Logger.subsystem, category: "RemoteInterface")
+    }
+
+    func currentCapabilities(
+        account: Account,
+        options: NKRequestOptions = .init(),
+        taskHandler: @escaping (_ task: URLSessionTask) -> Void = { _ in }
+    ) async -> (account: String, capabilities: Capabilities?, data: Data?, error: NKError) {
+        let ncKitAccount = account.ncKitAccount
+        await RetrievedCapabilitiesActor.shared.awaitFetchCompletion(forAccount: ncKitAccount)
+        guard let lastRetrieval = await RetrievedCapabilitiesActor.shared.data[ncKitAccount],
+              lastRetrieval.retrievedAt.timeIntervalSince(Date()) > -CapabilitiesFetchInterval
+        else {
+            return await fetchCapabilities(
+                account: account, options: options, taskHandler: taskHandler
+            )
+        }
+        return (account.ncKitAccount, lastRetrieval.capabilities, nil, .success)
+    }
+
+    func supportsTrash(
+        account: Account,
+        options: NKRequestOptions = .init(),
+        taskHandler: @escaping (_ task: URLSessionTask) -> Void = { _ in }
+    ) async -> Bool {
+        var remoteSupportsTrash = false
+        let (_, capabilities, _, _) = await currentCapabilities(
+            account: account, options: .init(), taskHandler: { _ in }
+        )
+        if let filesCapabilities = capabilities?.files {
+            remoteSupportsTrash = filesCapabilities.undelete
+        } else {
+            logger.warning("Could not get capabilities, will assume trash is unavailable.")
+        }
+        return remoteSupportsTrash
+    }
+}

Sources/NextcloudFileProviderKit/Item/Item+Create.swift

@@ -99,7 +99,8 @@ public extension Item {
             parentItemIdentifier: parentItemIdentifier,
             account: account,
             remoteInterface: remoteInterface,
-            dbManager: dbManager
+            dbManager: dbManager,
+            remoteSupportsTrash: await remoteInterface.supportsTrash(account: account)
         )
 
         return (fpItem, nil)
@@ -216,7 +217,8 @@ public extension Item {
             parentItemIdentifier: itemTemplate.parentItemIdentifier,
             account: account,
             remoteInterface: remoteInterface,
-            dbManager: dbManager
+            dbManager: dbManager,
+            remoteSupportsTrash: await remoteInterface.supportsTrash(account: account)
         )
 
         return (fpItem, nil)
@@ -412,7 +414,8 @@ public extension Item {
             parentItemIdentifier: rootItem.parentItemIdentifier,
             account: account,
             remoteInterface: remoteInterface,
-            dbManager: dbManager
+            dbManager: dbManager,
+            remoteSupportsTrash: await remoteInterface.supportsTrash(account: account)
         )
     }
 
@@ -495,7 +498,7 @@ public extension Item {
 
         let relativePath = parentItemRelativePath + "/" + itemTemplate.filename
         guard ignoredFiles == nil || ignoredFiles?.isExcluded(relativePath) == false else {
-            return Item.createIgnored(
+            return await Item.createIgnored(
                 basedOn: itemTemplate,
                 parentItemRemotePath: parentItemRemotePath,
                 contents: url,
@@ -604,7 +607,8 @@ public extension Item {
                     parentItemIdentifier: parentItemIdentifier,
                     account: account,
                     remoteInterface: remoteInterface,
-                    dbManager: dbManager
+                    dbManager: dbManager,
+                    remoteSupportsTrash: await remoteInterface.supportsTrash(account: account)
                 )
             }
 

Sources/NextcloudFileProviderKit/Item/Item+Fetch.swift

@@ -304,7 +304,8 @@ public extension Item {
             parentItemIdentifier: parentItemIdentifier,
             account: account,
             remoteInterface: remoteInterface,
-            dbManager: dbManager
+            dbManager: dbManager,
+            remoteSupportsTrash: await remoteInterface.supportsTrash(account: account)
         )
 
         return (localPath, fpItem, nil)

Sources/NextcloudFileProviderKit/Item/Item+Ignored.swift

@@ -17,7 +17,7 @@ extension Item {
         remoteInterface: RemoteInterface,
         progress: Progress,
         dbManager: FilesDatabaseManager
-    ) -> (Item?, Error?) {
+    ) async -> (Item?, Error?) {
         let filename = itemTemplate.filename
         Self.logger.info(
             """
@@ -60,7 +60,8 @@ extension Item {
             parentItemIdentifier: itemTemplate.parentItemIdentifier,
             account: account,
             remoteInterface: remoteInterface,
-            dbManager: dbManager
+            dbManager: dbManager,
+            remoteSupportsTrash: await remoteInterface.supportsTrash(account: account)
         )
 
         if #available(macOS 13.0, *) {

Sources/NextcloudFileProviderKit/Item/Item+LockFile.swift

@@ -140,7 +140,8 @@ extension Item {
                 parentItemIdentifier: parentItemIdentifier,
                 account: account,
                 remoteInterface: remoteInterface,
-                dbManager: dbManager
+                dbManager: dbManager,
+                remoteSupportsTrash: await remoteInterface.supportsTrash(account: account)
             ),
             returnError
         )
@@ -167,7 +168,7 @@ extension Item {
         )
         assert(isLockFileName(filename), "Should not handle non-lock files here.")
 
-        guard let modifiedItem = modifyUnuploaded(
+        guard let modifiedItem = await modifyUnuploaded(
             itemTarget: itemTarget,
             baseVersion: baseVersion,
             changedFields: changedFields,

Sources/NextcloudFileProviderKit/Item/Item+Modify.swift

@@ -88,7 +88,8 @@ public extension Item {
             parentItemIdentifier: newParentItemIdentifier,
             account: account,
             remoteInterface: remoteInterface,
-            dbManager: dbManager
+            dbManager: dbManager,
+            remoteSupportsTrash: await remoteInterface.supportsTrash(account: account)
         )
         return (modifiedItem, nil)
     }
@@ -224,7 +225,8 @@ public extension Item {
             parentItemIdentifier: parentItemIdentifier,
             account: account,
             remoteInterface: remoteInterface,
-            dbManager: dbManager
+            dbManager: dbManager,
+            remoteSupportsTrash: await remoteInterface.supportsTrash(account: account)
         )
         return (modifiedItem, nil)
     }
@@ -517,7 +519,8 @@ public extension Item {
             parentItemIdentifier: parentItemIdentifier,
             account: account,
             remoteInterface: remoteInterface,
-            dbManager: dbManager
+            dbManager: dbManager,
+            remoteSupportsTrash: await remoteInterface.supportsTrash(account: account)
         )
     }
 
@@ -565,7 +568,7 @@ public extension Item {
                     Will delete locally with no remote effect.
                 """
             )
-            guard let modifiedIgnored = modifyUnuploaded(
+            guard let modifiedIgnored = await modifyUnuploaded(
                 itemTarget: itemTarget,
                 baseVersion: baseVersion,
                 changedFields: changedFields,

Sources/NextcloudFileProviderKit/Item/Item+Trash.swift

@@ -45,7 +45,8 @@ extension Item {
             parentItemIdentifier: .trashContainer,
             account: account,
             remoteInterface: modifiedItem.remoteInterface,
-            dbManager: dbManager
+            dbManager: dbManager,
+            remoteSupportsTrash: await modifiedItem.remoteInterface.supportsTrash(account: account)
         )
 
         // The server may have renamed the trashed file so we need to scan the entire trash
@@ -106,7 +107,8 @@ extension Item {
             parentItemIdentifier: .trashContainer,
             account: account,
             remoteInterface: modifiedItem.remoteInterface,
-            dbManager: dbManager
+            dbManager: dbManager,
+            remoteSupportsTrash: await modifiedItem.remoteInterface.supportsTrash(account: account)
         )
 
         // Now we can directly update info on the child items
@@ -197,7 +199,8 @@ extension Item {
                 parentItemIdentifier: parentItemIdentifier,
                 account: account,
                 remoteInterface: modifiedItem.remoteInterface,
-                dbManager: dbManager
+                dbManager: dbManager,
+                remoteSupportsTrash: await modifiedItem.remoteInterface.supportsTrash(account: account)
             ), nil)
         }
 

Sources/NextcloudFileProviderKit/Item/Item+Unuploaded.swift

@@ -75,7 +75,7 @@ extension Item {
         forcedChunkSize: Int? = nil,
         progress: Progress = .init(),
         dbManager: FilesDatabaseManager
-    ) -> Item? {
+    ) async -> Item? {
         var modifiedParentItemIdentifier = parentItemIdentifier
         var modifiedMetadata = metadata
 
@@ -124,7 +124,8 @@ extension Item {
             parentItemIdentifier: modifiedParentItemIdentifier,
             account: account,
             remoteInterface: remoteInterface,
-            dbManager: dbManager
+            dbManager: dbManager,
+            remoteSupportsTrash: await remoteInterface.supportsTrash(account: account)
         )
     }
 }