Add support for thumbnails in FileProviderExtension

Signed-off-by: Claudio Cambra <claudio.cambra@nextcloud.com>

shell_integration/MacOSX/NextcloudIntegration/FileProviderExt/FileProviderExtension+Thumbnailing.swift

@@ -0,0 +1,62 @@
+/*
+ * Copyright (C) 2023 by Claudio Cambra <claudio.cambra@nextcloud.com>
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation; either version 2 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful, but
+ * WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY
+ * or FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
+ * for more details.
+ */
+
+import Foundation
+import FileProvider
+import NextcloudKit
+import OSLog
+
+extension FileProviderExtension: NSFileProviderThumbnailing {
+    func fetchThumbnails(for itemIdentifiers: [NSFileProviderItemIdentifier],
+                         requestedSize size: CGSize,
+                         perThumbnailCompletionHandler: @escaping (NSFileProviderItemIdentifier,
+                                                                   Data?,
+                                                                   Error?) -> Void,
+                         completionHandler: @escaping (Error?) -> Void) -> Progress {
+
+        let progress = Progress(totalUnitCount: Int64(itemIdentifiers.count))
+        var progressCounter: Int64 = 0
+
+        func finishCurrent() {
+            progressCounter += 1
+
+            if progressCounter == progress.totalUnitCount {
+                completionHandler(nil)
+            }
+        }
+
+        for itemIdentifier in itemIdentifiers {
+            Logger.fileProviderExtension.debug("Fetching thumbnail for item with identifier:\(itemIdentifier.rawValue, privacy: .public)")
+            guard let metadata = NextcloudFilesDatabaseManager.shared.itemMetadataFromFileProviderItemIdentifier(itemIdentifier),
+                  let thumbnailUrl = metadata.thumbnailUrl(size: size) else {
+                Logger.fileProviderExtension.debug("Did not fetch thumbnail URL")
+                finishCurrent()
+                continue
+            }
+
+            Logger.fileProviderExtension.debug("Fetching thumbnail for file:\(metadata.fileName) at:\(thumbnailUrl.absoluteString, privacy: .public)")
+
+            self.ncKit.getPreview(url: thumbnailUrl) { _, data, error in
+                if error == .success && data != nil {
+                    perThumbnailCompletionHandler(itemIdentifier, data, nil)
+                } else {
+                    perThumbnailCompletionHandler(itemIdentifier, nil, NSFileProviderError(.serverUnreachable))
+                }
+                finishCurrent()
+            }
+        }
+
+        return progress
+    }
+}

shell_integration/MacOSX/NextcloudIntegration/NextcloudIntegration.xcodeproj/project.pbxproj

@@ -17,6 +17,7 @@
 		5318AD9929BF58D000CBB71C /* NKError+Extensions.swift in Sources */ = {isa = PBXBuildFile; fileRef = 5318AD9829BF58D000CBB71C /* NKError+Extensions.swift */; };
 		5352B36629DC14970011CE03 /* NextcloudFilesDatabaseManager+Directories.swift in Sources */ = {isa = PBXBuildFile; fileRef = 5352B36529DC14970011CE03 /* NextcloudFilesDatabaseManager+Directories.swift */; };
 		5352B36829DC17D60011CE03 /* NextcloudFilesDatabaseManager+LocalFiles.swift in Sources */ = {isa = PBXBuildFile; fileRef = 5352B36729DC17D60011CE03 /* NextcloudFilesDatabaseManager+LocalFiles.swift */; };
+		5352B36C29DC44B50011CE03 /* FileProviderExtension+Thumbnailing.swift in Sources */ = {isa = PBXBuildFile; fileRef = 5352B36B29DC44B50011CE03 /* FileProviderExtension+Thumbnailing.swift */; };
 		5352E85B29B7BFE6002CE85C /* Progress+Extensions.swift in Sources */ = {isa = PBXBuildFile; fileRef = 5352E85A29B7BFE6002CE85C /* Progress+Extensions.swift */; };
 		535AE30E29C0A2CC0042A9BA /* Logger+Extensions.swift in Sources */ = {isa = PBXBuildFile; fileRef = 535AE30D29C0A2CC0042A9BA /* Logger+Extensions.swift */; };
 		536EFBF7295CF58100F4CB13 /* FileProviderSocketLineProcessor.swift in Sources */ = {isa = PBXBuildFile; fileRef = 536EFBF6295CF58100F4CB13 /* FileProviderSocketLineProcessor.swift */; };
@@ -146,6 +147,7 @@
 		5318AD9829BF58D000CBB71C /* NKError+Extensions.swift */ = {isa = PBXFileReference; lastKnownFileType = sourcecode.swift; path = "NKError+Extensions.swift"; sourceTree = "<group>"; };
 		5352B36529DC14970011CE03 /* NextcloudFilesDatabaseManager+Directories.swift */ = {isa = PBXFileReference; lastKnownFileType = sourcecode.swift; path = "NextcloudFilesDatabaseManager+Directories.swift"; sourceTree = "<group>"; };
 		5352B36729DC17D60011CE03 /* NextcloudFilesDatabaseManager+LocalFiles.swift */ = {isa = PBXFileReference; lastKnownFileType = sourcecode.swift; path = "NextcloudFilesDatabaseManager+LocalFiles.swift"; sourceTree = "<group>"; };
+		5352B36B29DC44B50011CE03 /* FileProviderExtension+Thumbnailing.swift */ = {isa = PBXFileReference; lastKnownFileType = sourcecode.swift; path = "FileProviderExtension+Thumbnailing.swift"; sourceTree = "<group>"; };
 		5352E85A29B7BFE6002CE85C /* Progress+Extensions.swift */ = {isa = PBXFileReference; lastKnownFileType = sourcecode.swift; path = "Progress+Extensions.swift"; sourceTree = "<group>"; };
 		535AE30D29C0A2CC0042A9BA /* Logger+Extensions.swift */ = {isa = PBXFileReference; lastKnownFileType = sourcecode.swift; path = "Logger+Extensions.swift"; sourceTree = "<group>"; };
 		536EFBF6295CF58100F4CB13 /* FileProviderSocketLineProcessor.swift */ = {isa = PBXFileReference; lastKnownFileType = sourcecode.swift; path = FileProviderSocketLineProcessor.swift; sourceTree = "<group>"; };
@@ -263,6 +265,7 @@
 				53ED471F29C5E64200795DB1 /* FileProviderEnumerator+SyncEngine.swift */,
 				538E396C27F4765000FA63D5 /* FileProviderExtension.swift */,
 				53ED472F29C9CE0B00795DB1 /* FileProviderExtension+ClientInterface.swift */,
+				5352B36B29DC44B50011CE03 /* FileProviderExtension+Thumbnailing.swift */,
 				538E396E27F4765000FA63D5 /* FileProviderItem.swift */,
 				5318AD9629BF493600CBB71C /* FileProviderMaterialisedEnumerationObserver.swift */,
 				536EFBF6295CF58100F4CB13 /* FileProviderSocketLineProcessor.swift */,
@@ -589,6 +592,7 @@
 				5318AD9129BF42FB00CBB71C /* NextcloudItemMetadataTable.swift in Sources */,
 				5352B36629DC14970011CE03 /* NextcloudFilesDatabaseManager+Directories.swift in Sources */,
 				5318AD9729BF493600CBB71C /* FileProviderMaterialisedEnumerationObserver.swift in Sources */,
+				5352B36C29DC44B50011CE03 /* FileProviderExtension+Thumbnailing.swift in Sources */,
 				538E397127F4765000FA63D5 /* FileProviderEnumerator.swift in Sources */,
 			);
 			runOnlyForDeploymentPostprocessing = 0;