Implemented 'reveal in finder' environment action

This action is optional to implement and is just 'nil' on platforms
that don't support such an action

Author: stackotter

Sources/AppKitBackend/AppKitBackend.swift

@@ -22,6 +22,7 @@ public final class AppKitBackend: AppBackend {
     public let defaultToggleStyle = ToggleStyle.button
     public let requiresImageUpdateOnScaleFactorChange = false
     public let menuImplementationStyle = MenuImplementationStyle.dynamicPopover
+    public let canRevealFiles = true
 
     public var scrollBarWidth: Int {
         // We assume that all scrollers have their controlSize set to `.regular` by default.
@@ -123,6 +124,10 @@ public final class AppKitBackend: AppBackend {
         NSWorkspace.shared.open(url)
     }
 
+    public func revealFile(_ url: URL) throws {
+        NSWorkspace.shared.activateFileViewerSelecting([url])
+    }
+
     private static func renderMenuItems(_ items: [ResolvedMenu.Item]) -> [NSMenuItem] {
         items.map { item in
             switch item {

Sources/Gtk3Backend/Gtk3Backend.swift

@@ -31,6 +31,7 @@ public final class Gtk3Backend: AppBackend {
     public let defaultToggleStyle = ToggleStyle.button
     public let requiresImageUpdateOnScaleFactorChange = true
     public let menuImplementationStyle = MenuImplementationStyle.dynamicPopover
+    public let canRevealFiles = true
 
     var gtkApp: Application
 
@@ -261,6 +262,42 @@ public final class Gtk3Backend: AppBackend {
         }
     }
 
+    public func revealFile(_ url: URL) throws {
+        var success = false
+
+        #if !os(Windows)
+            let fileURI = url.absoluteString.replacingOccurrences(
+                of: ",",
+                with: "\\,"
+            )
+            let process = Process()
+            process.arguments = [
+                "dbus-send", "--print-reply",
+                "--dest=org.freedesktop.FileManager1",
+                "/org/freedesktop/FileManager1",
+                "org.freedesktop.FileManager1.ShowItems",
+                "array:string:\(fileURI)",
+                "string:"
+            ]
+            process.executableURL = URL(fileURLWithPath: "/usr/bin/env")
+
+            do {
+                try process.run()
+                process.waitUntilExit()
+
+                success = process.terminationStatus == 0
+            } catch {
+                // Fall through to fallback
+            }
+        #endif
+
+        if !success {
+            // Fall back to opening the parent directory without highlighting
+            // the file.
+            try openExternalURL(url.deletingLastPathComponent())
+        }
+    }
+
     class ThreadActionContext {
         var action: () -> Void
 

Sources/GtkBackend/GtkBackend.swift

@@ -31,6 +31,7 @@ public final class GtkBackend: AppBackend {
     public let defaultToggleStyle = ToggleStyle.button
     public let requiresImageUpdateOnScaleFactorChange = false
     public let menuImplementationStyle = MenuImplementationStyle.dynamicPopover
+    public let canRevealFiles = true
 
     var gtkApp: Application
 
@@ -164,6 +165,39 @@ public final class GtkBackend: AppBackend {
         gtk_show_uri(nil, url.absoluteString, guint(GDK_CURRENT_TIME))
     }
 
+    public func revealFile(_ url: URL) throws {
+        var success = false
+
+        #if !os(Windows)
+            let fileURI = url.absoluteString.replacingOccurrences(
+                of: ",",
+                with: "\\,"
+            )
+            let process = Process()
+            process.arguments = [
+                "dbus-send", "--print-reply",
+                "--dest=org.freedesktop.FileManager1",
+                "/org/freedesktop/FileManager1",
+                "org.freedesktop.FileManager1.ShowItems",
+                "array:string:\(fileURI)",
+                "string:"
+            ]
+            process.executableURL = URL(fileURLWithPath: "/usr/bin/env")
+
+            do {
+                try process.run()
+                process.waitUntilExit()
+
+                success = process.terminationStatus == 0
+            } catch {
+                break
+            }
+        #endif
+
+        // Fall back to opening the parent directory without highlighting the file.
+        try openExternalURL(url.deletingLastPathComponent())
+    }
+
     private func renderMenu(
         _ menu: ResolvedMenu,
         actionMap: any GActionMap,

Sources/SwiftCrossUI/Backend/AppBackend.swift

@@ -88,6 +88,10 @@ public protocol AppBackend {
     /// are called.
     var menuImplementationStyle: MenuImplementationStyle { get }
 
+    /// Whether the backend can reveal files in the system file manager or not.
+    /// Mobile backends generally can't.
+    var canRevealFiles: Bool { get }
+
     /// Often in UI frameworks (such as Gtk), code is run in a callback
     /// after starting the app, and hence this generic root window creation
     /// API must reflect that. This is always the first method to be called
@@ -201,6 +205,10 @@ public protocol AppBackend {
     /// URL's protocol.
     func openExternalURL(_ url: URL) throws
 
+    /// Reveals a file in the system's file manager. This opens
+    /// the file's enclosing directory and highlighting the file.
+    func revealFile(_ url: URL) throws
+
     /// Shows a widget after it has been created or updated (may be unnecessary
     /// for some backends). Predominantly used by ``ViewGraphNode`` after
     /// propagating updates.
@@ -549,6 +557,10 @@ extension AppBackend {
         todo()
     }
 
+    public func revealFile(_ url: URL) throws {
+        todo()
+    }
+
     // MARK: Application
 
     public func setApplicationMenu(_ submenus: [ResolvedMenu.Submenu]) {

Sources/SwiftCrossUI/Environment/Actions/RevealFileAction.swift

@@ -0,0 +1,25 @@
+import Foundation
+
+/// Reveals a file in the system's file manager. This opens
+/// the file's enclosing directory and highlighting the file.
+public struct RevealFileAction {
+    let action: (URL) -> Void
+
+    init?<Backend: AppBackend>(backend: Backend) {
+        guard backend.canRevealFiles else {
+            return nil
+        }
+
+        action = { file in
+            do {
+                try backend.revealFile(file)
+            } catch {
+                print("warning: Failed to reveal file: \(error)")
+            }
+        }
+    }
+
+    public func callAsFunction(_ file: URL) {
+        action(file)
+    }
+}

Sources/SwiftCrossUI/Environment/EnvironmentValues.swift

@@ -119,6 +119,17 @@ public struct EnvironmentValues {
         )
     }
 
+    /// Reveals a file in the system's file manager. This opens
+    /// the file's enclosing directory and highlighting the file.
+    ///
+    /// `nil` on platforms that don't support revealing files, e.g.
+    /// iOS.
+    public var revealFile: RevealFileAction? {
+        return RevealFileAction(
+            backend: backend
+        )
+    }
+
     /// Creates the default environment.
     init<Backend: AppBackend>(backend: Backend) {
         self.backend = backend

Sources/UIKitBackend/UIKitBackend.swift

@@ -22,6 +22,8 @@ public final class UIKitBackend: AppBackend {
 
     public let requiresImageUpdateOnScaleFactorChange = false
 
+    public let canRevealFiles = false
+
     var onTraitCollectionChange: (() -> Void)?
 
     private let appDelegateClass: ApplicationDelegate.Type

Sources/WinUIBackend/WinUIBackend.swift

@@ -41,6 +41,7 @@ public final class WinUIBackend: AppBackend {
     public let defaultToggleStyle = ToggleStyle.button
     public let requiresImageUpdateOnScaleFactorChange = false
     public let menuImplementationStyle = MenuImplementationStyle.dynamicPopover
+    public let canRevealFiles = false
 
     public var scrollBarWidth: Int {
         12