refactor!: refactor drag and drop events

.changes/file-drop-enhancements.md

@@ -0,0 +1,10 @@
+---
+"wry": "patch"
+---
+
+**Breaking change**: Refactored the file-drop handling on the webview for better representation of the actual drag and drop operation:
+
+- Renamed `file-drop` cargo feature flag to `drag-drop`.
+- Removed `FileDropEvent` enum and replaced with a new `DragDropEvent` enum.
+- Renamed `WebViewAttributes::file_drop_handler` field to `WebViewAttributes::drag_drop_handler`.
+- Renamed `WebViewAttributes::with_file_drop_handler` method to `WebViewAttributes::with_drag_drop_handler`.

Cargo.toml

@@ -15,7 +15,7 @@ exclude = [ "/.changes", "/.github", "/audits", "/wry-logo.svg" ]
 
 [package.metadata.docs.rs]
 no-default-features = true
-features = [ "file-drop", "protocol", "os-webview" ]
+features = [ "drag-drop", "protocol", "os-webview" ]
 targets = [
   "x86_64-unknown-linux-gnu",
   "x86_64-pc-windows-msvc",
@@ -25,9 +25,9 @@ rustc-args = [ "--cfg", "docsrs" ]
 rustdoc-args = [ "--cfg", "docsrs" ]
 
 [features]
-default = [ "file-drop", "objc-exception", "protocol", "os-webview" ]
+default = [ "drag-drop", "objc-exception", "protocol", "os-webview" ]
 objc-exception = [ "objc/exception" ]
-file-drop = [ ]
+drag-drop = [ ]
 protocol = [ ]
 devtools = [ ]
 transparent = [ ]

examples/simple.rs

@@ -34,7 +34,24 @@ fn main() -> wry::Result<()> {
     WebViewBuilder::new_gtk(vbox)
   };
 
-  let _webview = builder.with_url("http://tauri.app").build()?;
+  let _webview = builder
+    .with_url("http://tauri.app")
+    .with_drag_drop_handler(|e| {
+      match e {
+        wry::DragDropEvent::Enter { paths, position } => {
+          println!("DragEnter: {position:?} {paths:?} ")
+        }
+        wry::DragDropEvent::Over { position } => println!("DragOver: {position:?} "),
+        wry::DragDropEvent::Drop { paths, position } => {
+          println!("DragDrop: {position:?} {paths:?} ")
+        }
+        wry::DragDropEvent::Leave => println!("DragLeave"),
+        _ => {}
+      }
+
+      true
+    })
+    .build()?;
 
   event_loop.run(move |event, _, control_flow| {
     *control_flow = ControlFlow::Wait;

src/lib.rs

@@ -179,7 +179,7 @@
 //! for the crate to work. This feature was added in preparation of other ports like cef and servo.
 //! - `protocol` (default): Enables [`WebViewBuilder::with_custom_protocol`] to define custom URL scheme for handling tasks like
 //! loading assets.
-//! - `file-drop` (default): Enables [`WebViewBuilder::with_file_drop_handler`] to control the behaviour when there are files
+//! - `drag-drop` (default): Enables [`WebViewBuilder::with_drag_drop_handler`] to control the behaviour when there are files
 //! interacting with the window.
 //! - `devtools`: Enables devtools on release builds. Devtools are always enabled in debug builds.
 //! On **macOS**, enabling devtools, requires calling private apis so you should not enable this flag in release
@@ -191,10 +191,11 @@
 //! libraries and prevent from building documentation on doc.rs fails.
 //! - `linux-body`: Enables body support of custom protocol request on Linux. Requires
 //! webkit2gtk v2.40 or above.
-//! - `tracing`: enables [tracing] for `evaluate_script`, `ipc_handler` and `custom_protocols.
+//! - `tracing`: enables [`tracing`] for `evaluate_script`, `ipc_handler` and `custom_protocols.
 //!
 //! [`tao`]: https://docs.rs/tao
 //! [`winit`]: https://docs.rs/winit
+//! [`tracing`]: https://docs.rs/tracing
 
 #![allow(clippy::new_without_default)]
 #![allow(clippy::default_constructed_unit_structs)]
@@ -376,17 +377,18 @@ pub struct WebViewAttributes {
   /// using `window.ipc.postMessage("insert_message_here")` to host Rust code.
   pub ipc_handler: Option<Box<dyn Fn(Request<String>)>>,
 
-  /// A handler closure to process incoming [`FileDropEvent`] of the webview.
+  /// A handler closure to process incoming [`DragDropEvent`] of the webview.
   ///
   /// # Blocking OS Default Behavior
-  /// Return `true` in the callback to block the OS' default behavior of handling a file drop.
+  /// Return `true` in the callback to block the OS' default behavior.
   ///
   /// Note, that if you do block this behavior, it won't be possible to drop files on `<input type="file">` forms.
   /// Also note, that it's not possible to manually set the value of a `<input type="file">` via JavaScript for security reasons.
-  #[cfg(feature = "file-drop")]
-  pub file_drop_handler: Option<Box<dyn Fn(FileDropEvent) -> bool>>,
-  #[cfg(not(feature = "file-drop"))]
-  file_drop_handler: Option<Box<dyn Fn(FileDropEvent) -> bool>>,
+  #[cfg(feature = "drag-drop")]
+  #[cfg_attr(docsrs, doc(cfg(feature = "drag-drop")))]
+  pub drag_drop_handler: Option<Box<dyn Fn(DragDropEvent) -> bool>>,
+  #[cfg(not(feature = "drag-drop"))]
+  drag_drop_handler: Option<Box<dyn Fn(DragDropEvent) -> bool>>,
 
   /// A navigation handler to decide if incoming url is allowed to navigate.
   ///
@@ -505,7 +507,7 @@ impl Default for WebViewAttributes {
       initialization_scripts: vec![],
       custom_protocols: vec![],
       ipc_handler: None,
-      file_drop_handler: None,
+      drag_drop_handler: None,
       navigation_handler: None,
       download_started_handler: None,
       download_completed_handler: None,
@@ -560,7 +562,7 @@ impl<'a> WebViewBuilder<'a> {
   ///   by callling [`gtk::init`] and advance its loop alongside your event loop using [`gtk::main_iteration_do`].
   ///   Checkout the [Platform Considerations](https://docs.rs/wry/latest/wry/#platform-considerations) section in the crate root documentation.
   /// - **Windows**: The webview will auto-resize when the passed handle is resized.
-  /// - **Linux (X11)**: Unlike macOS and Windows, the webview will not auto-resize and you'll need to call [`WebView::set_size`] manually.
+  /// - **Linux (X11)**: Unlike macOS and Windows, the webview will not auto-resize and you'll need to call [`WebView::set_bounds`] manually.
   ///
   /// # Panics:
   ///
@@ -768,19 +770,20 @@ impl<'a> WebViewBuilder<'a> {
     self
   }
 
-  /// Set a handler closure to process incoming [`FileDropEvent`] of the webview.
+  /// Set a handler closure to process incoming [`DragDropEvent`] of the webview.
   ///
   /// # Blocking OS Default Behavior
-  /// Return `true` in the callback to block the OS' default behavior of handling a file drop.
+  /// Return `true` in the callback to block the OS' default behavior.
   ///
   /// Note, that if you do block this behavior, it won't be possible to drop files on `<input type="file">` forms.
   /// Also note, that it's not possible to manually set the value of a `<input type="file">` via JavaScript for security reasons.
-  #[cfg(feature = "file-drop")]
-  pub fn with_file_drop_handler<F>(mut self, handler: F) -> Self
+  #[cfg(feature = "drag-drop")]
+  #[cfg_attr(docsrs, doc(cfg(feature = "drag-drop")))]
+  pub fn with_drag_drop_handler<F>(mut self, handler: F) -> Self
   where
-    F: Fn(FileDropEvent) -> bool + 'static,
+    F: Fn(DragDropEvent) -> bool + 'static,
   {
-    self.attrs.file_drop_handler = Some(Box::new(handler));
+    self.attrs.drag_drop_handler = Some(Box::new(handler));
     self
   }
 
@@ -789,7 +792,7 @@ impl<'a> WebViewBuilder<'a> {
   ///
   /// ## Note
   ///
-  /// Data URLs are not supported, use [`html`](Self::html) option instead.
+  /// Data URLs are not supported, use [`html`](Self::with_html) option instead.
   pub fn with_url_and_headers(mut self, url: impl Into<String>, headers: http::HeaderMap) -> Self {
     self.attrs.url = Some(url.into());
     self.attrs.headers = Some(headers);
@@ -801,7 +804,7 @@ impl<'a> WebViewBuilder<'a> {
   ///
   /// ## Note
   ///
-  /// Data URLs are not supported, use [`html`](Self::html) option instead.
+  /// Data URLs are not supported, use [`html`](Self::with_html) option instead.
   pub fn with_url(mut self, url: impl Into<String>) -> Self {
     self.attrs.url = Some(url.into());
     self.attrs.headers = None;
@@ -1067,7 +1070,7 @@ pub trait WebViewBuilderExtWindows {
   /// `false`, it disables all accelerator keys that access features specific to a web browser.
   /// The default value is `true`. See the following link to know more details.
   ///
-  /// https://learn.microsoft.com/en-us/microsoft-edge/webview2/reference/winrt/microsoft_web_webview2_core/corewebview2settings#arebrowseracceleratorkeysenabled
+  /// <https://learn.microsoft.com/en-us/microsoft-edge/webview2/reference/winrt/microsoft_web_webview2_core/corewebview2settings#arebrowseracceleratorkeysenabled>
   fn with_browser_accelerator_keys(self, enabled: bool) -> Self;
 
   /// Specifies the theme of webview2. This affects things like `prefers-color-scheme`.
@@ -1250,7 +1253,7 @@ impl WebView {
   ///   by callling [`gtk::init`] and advance its loop alongside your event loop using [`gtk::main_iteration_do`].
   ///   Checkout the [Platform Considerations](https://docs.rs/wry/latest/wry/#platform-considerations) section in the crate root documentation.
   /// - **macOS / Windows**: The webview will auto-resize when the passed handle is resized.
-  /// - **Linux (X11)**: Unlike macOS and Windows, the webview will not auto-resize and you'll need to call [`WebView::set_size`] manually.
+  /// - **Linux (X11)**: Unlike macOS and Windows, the webview will not auto-resize and you'll need to call [`WebView::set_bounds`] manually.
   ///
   /// # Panics:
   ///
@@ -1410,24 +1413,31 @@ impl WebView {
   }
 }
 
-/// An event describing the files drop on the webview.
+/// An event describing drag and drop operations on the webview.
 #[non_exhaustive]
 #[derive(Debug, serde::Serialize, Clone)]
-pub enum FileDropEvent {
-  /// The file(s) have been dragged onto the window, but have not been dropped yet.
-  Hovered {
+pub enum DragDropEvent {
+  /// A drag operation has entered the webview.
+  Enter {
+    /// List of paths that are being dragged onto the webview.
     paths: Vec<PathBuf>,
-    /// The position of the mouse cursor.
+    /// Position of the drag operation, relative to the webview top-left corner.
+    position: (i32, i32),
+  },
+  /// A drag operation is moving over the window.
+  Over {
+    /// Position of the drag operation, relative to the webview top-left corner.
     position: (i32, i32),
   },
   /// The file(s) have been dropped onto the window.
-  Dropped {
+  Drop {
+    /// List of paths that are being dropped onto the window.
     paths: Vec<PathBuf>,
-    /// The position of the mouse cursor.
+    /// Position of the drag operation, relative to the webview top-left corner.
     position: (i32, i32),
   },
-  /// The file drop was aborted.
-  Cancelled,
+  /// The drag operation has been cancelled or left the window.
+  Leave,
 }
 
 /// Get WebView/Webkit version on current platform.

src/webkitgtk/drag_drop.rs

@@ -0,0 +1,125 @@
+// Copyright 2020-2023 Tauri Programme within The Commons Conservancy
+// SPDX-License-Identifier: Apache-2.0
+// SPDX-License-Identifier: MIT
+
+use std::{
+  cell::{Cell, UnsafeCell},
+  path::PathBuf,
+  rc::Rc,
+};
+
+use gtk::{glib::GString, prelude::*};
+use webkit2gtk::WebView;
+
+use crate::DragDropEvent;
+
+struct DragDropController {
+  paths: UnsafeCell<Option<Vec<PathBuf>>>,
+  has_entered: Cell<bool>,
+  position: Cell<(i32, i32)>,
+  handler: Box<dyn Fn(DragDropEvent) -> bool>,
+}
+
+impl DragDropController {
+  fn new(handler: Box<dyn Fn(DragDropEvent) -> bool>) -> Self {
+    Self {
+      handler,
+      paths: UnsafeCell::new(None),
+      has_entered: Cell::new(false),
+      position: Cell::new((0, 0)),
+    }
+  }
+
+  fn store_paths(&self, paths: Vec<PathBuf>) {
+    unsafe { *self.paths.get() = Some(paths) };
+  }
+
+  fn take_paths(&self) -> Option<Vec<PathBuf>> {
+    unsafe { &mut *self.paths.get() }.take()
+  }
+
+  fn store_position(&self, position: (i32, i32)) {
+    self.position.replace(position);
+  }
+
+  fn enter(&self) {
+    self.has_entered.set(true);
+  }
+
+  fn has_entered(&self) -> bool {
+    self.has_entered.get()
+  }
+
+  fn leave(&self) {
+    self.has_entered.set(false);
+  }
+
+  fn call(&self, event: DragDropEvent) -> bool {
+    (self.handler)(event)
+  }
+}
+
+pub(crate) fn connect_drag_event(webview: &WebView, handler: Box<dyn Fn(DragDropEvent) -> bool>) {
+  let controller = Rc::new(DragDropController::new(handler));
+
+  {
+    let controller = controller.clone();
+    webview.connect_drag_data_received(move |_, _, _, _, data, info, _| {
+      if info == 2 {
+        let uris = data.uris();
+        let paths = uris.iter().map(path_buf_from_uri).collect::<Vec<_>>();
+        controller.enter();
+        controller.call(DragDropEvent::Enter {
+          paths: paths.clone(),
+          position: controller.position.get(),
+        });
+        controller.store_paths(paths);
+      }
+    });
+  }
+
+  {
+    let controller = controller.clone();
+    webview.connect_drag_motion(move |_, _, x, y, _| {
+      if controller.has_entered() {
+        controller.call(DragDropEvent::Over { position: (x, y) });
+      } else {
+        controller.store_position((x, y));
+      }
+      false
+    });
+  }
+
+  {
+    let controller = controller.clone();
+    webview.connect_drag_drop(move |_, _, x, y, _| {
+      if controller.has_entered() {
+        if let Some(paths) = controller.take_paths() {
+          controller.leave();
+          return controller.call(DragDropEvent::Drop {
+            paths,
+            position: (x, y),
+          });
+        }
+      }
+
+      false
+    });
+  }
+
+  webview.connect_drag_leave(move |_, _, time| {
+    if time == 0 {
+      controller.leave();
+      controller.call(DragDropEvent::Leave);
+    }
+  });
+}
+
+fn path_buf_from_uri(gstr: &GString) -> PathBuf {
+  let path = gstr.as_str();
+  let path = path.strip_prefix("file://").unwrap_or(path);
+  let path = percent_encoding::percent_decode(path.as_bytes())
+    .decode_utf8_lossy()
+    .to_string();
+  PathBuf::from(path)
+}