Add option to specify persistence path

crates/eframe/src/epi.rs

@@ -362,6 +362,10 @@ pub struct NativeOptions {
  /// Controls whether or not the native window position and size will be
  /// persisted (only if the "persistence" feature is enabled).
  pub persist_window: bool,
+
+ /// The folder where `eframe` will store the app state. If not set, eframe will get the paths
+ /// from [directories_next].
+ pub persistence_path: Option<std::path::PathBuf>,
 }
 
 #[cfg(not(target_arch = "wasm32"))]
@@ -379,6 +383,8 @@ impl Clone for NativeOptions {
  #[cfg(feature = "wgpu")]
  wgpu_options: self.wgpu_options.clone(),
 
+ persistence_path: self.persistence_path.clone(),
+
  ..*self
  }
  }
@@ -418,6 +424,9 @@ impl Default for NativeOptions {
  wgpu_options: egui_wgpu::WgpuConfiguration::default(),
 
  persist_window: true,
+
+ #[cfg(feature = "persistence")]
+ persistence_path: None,
  }
  }
 }

crates/eframe/src/native/epi_integration.rs

@@ -1,6 +1,8 @@
 //! Common tools used by [`super::glow_integration`] and [`super::wgpu_integration`].
 
 use web_time::Instant;
+
+use std::path::PathBuf;
 use winit::event_loop::EventLoopWindowTarget;
 
 use raw_window_handle::{HasDisplayHandle as _, HasWindowHandle as _};
@@ -129,6 +131,15 @@ pub fn create_storage(_app_name: &str) -> Option<Box<dyn epi::Storage>> {
  None
 }
 
+pub fn create_storage_with_file(file: impl Into<PathBuf>) -> Option<Box<dyn epi::Storage>> {
+ #[cfg(feature = "persistence")]
+ return Some(Box::new(
+ super::file_storage::FileStorage::from_ron_filepath(file),
+ ));
+ #[cfg(not(feature = "persistence"))]
+ None
+}
+
 // ----------------------------------------------------------------------------
 
 /// Everything needed to make a winit-based integration for [`epi`].

crates/eframe/src/native/file_storage.rs

@@ -41,7 +41,7 @@ impl Drop for FileStorage {
 
 impl FileStorage {
  /// Store the state in this .ron file.
- fn from_ron_filepath(ron_filepath: impl Into<PathBuf>) -> Self {
+ pub(crate) fn from_ron_filepath(ron_filepath: impl Into<PathBuf>) -> Self {
  crate::profile_function!();
  let ron_filepath: PathBuf = ron_filepath.into();
  log::debug!("Loading app state from {:?}…", ron_filepath);

crates/eframe/src/native/glow_integration.rs

@@ -195,13 +195,17 @@ impl GlowWinitApp {
  ) -> Result<&mut GlowWinitRunning> {
  crate::profile_function!();
 
- let storage = epi_integration::create_storage(
- self.native_options
- .viewport
- .app_id
- .as_ref()
- .unwrap_or(&self.app_name),
- );
+ let storage = if let Some(file) = &self.native_options.persistence_path {
+ epi_integration::create_storage_with_file(file)
+ } else {
+ epi_integration::create_storage(
+ self.native_options
+ .viewport
+ .app_id
+ .as_ref()
+ .unwrap_or(&self.app_name),
+ )
+ };
 
  let egui_ctx = create_egui_context(storage.as_deref());
 

crates/eframe/src/native/wgpu_integration.rs

@@ -420,13 +420,17 @@ impl WinitApp for WgpuWinitApp {
  self.recreate_window(event_loop, running);
  running
  } else {
- let storage = epi_integration::create_storage(
- self.native_options
- .viewport
- .app_id
- .as_ref()
- .unwrap_or(&self.app_name),
- );
+ let storage = if let Some(file) = &self.native_options.persistence_path {
+ epi_integration::create_storage_with_file(file)
+ } else {
+ epi_integration::create_storage(
+ self.native_options
+ .viewport
+ .app_id
+ .as_ref()
+ .unwrap_or(&self.app_name),
+ )
+ };
  let egui_ctx = winit_integration::create_egui_context(storage.as_deref());
  let (window, builder) = create_window(
  &egui_ctx,