servoshell: Migrate to egui-file-dialog from tinyfiledialogs (#34823)

This is the first step toward completely replacing tinyfiledialogs with
an egui-based solution.

Signed-off-by: L Ashwin B <lashwinib@gmail.com>

ports/servoshell/desktop/dialog.rs

@@ -0,0 +1,95 @@
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at https://mozilla.org/MPL/2.0/. */
+
+use std::path::{Path, PathBuf};
+use std::sync::Arc;
+
+use egui_file_dialog::{DialogState, FileDialog as EguiFileDialog};
+use log::warn;
+use servo::ipc_channel::ipc::IpcSender;
+use servo::FilterPattern;
+
+#[derive(Debug)]
+pub struct FileDialog {
+    dialog: EguiFileDialog,
+    multiple: bool,
+    response_sender: IpcSender<Option<Vec<PathBuf>>>,
+}
+
+#[derive(Debug)]
+pub enum Dialog {
+    File(FileDialog),
+}
+
+impl Dialog {
+    pub fn new_file_dialog(
+        multiple: bool,
+        response_sender: IpcSender<Option<Vec<PathBuf>>>,
+        patterns: Vec<FilterPattern>,
+    ) -> Self {
+        let mut dialog = EguiFileDialog::new();
+        if !patterns.is_empty() {
+            dialog = dialog
+                .add_file_filter(
+                    "All Supported Types",
+                    Arc::new(move |path: &Path| {
+                        path.extension()
+                            .and_then(|e| e.to_str())
+                            .map_or(false, |ext| {
+                                let ext = ext.to_lowercase();
+                                patterns.iter().any(|pattern| ext == pattern.0)
+                            })
+                    }),
+                )
+                .default_file_filter("All Supported Types");
+        }
+
+        let dialog = FileDialog {
+            dialog,
+            multiple,
+            response_sender,
+        };
+
+        Dialog::File(dialog)
+    }
+
+    pub fn update(&mut self, ctx: &egui::Context) -> bool {
+        match self {
+            Dialog::File(dialog) => {
+                if dialog.dialog.state() == DialogState::Closed {
+                    if dialog.multiple {
+                        dialog.dialog.pick_multiple();
+                    } else {
+                        dialog.dialog.pick_file();
+                    }
+                }
+
+                let state = dialog.dialog.update(ctx).state();
+
+                match state {
+                    DialogState::Open => true,
+                    DialogState::Selected(path) => {
+                        if let Err(e) = dialog.response_sender.send(Some(vec![path])) {
+                            warn!("Failed to send file selection response: {}", e);
+                        }
+                        false
+                    },
+                    DialogState::SelectedMultiple(paths) => {
+                        if let Err(e) = dialog.response_sender.send(Some(paths)) {
+                            warn!("Failed to send file selection response: {}", e);
+                        }
+                        false
+                    },
+                    DialogState::Cancelled => {
+                        if let Err(e) = dialog.response_sender.send(None) {
+                            warn!("Failed to send cancellation response: {}", e);
+                        }
+                        false
+                    },
+                    DialogState::Closed => false,
+                }
+            },
+        }
+    }
+}