WIP local save file component

ferretro_components/examples/multifunction_emulator.rs

@@ -92,6 +92,8 @@ pub fn main() -> Result<(), Box<dyn std::error::Error + Send + Sync>> {
         save_path: Some(std::env::temp_dir()),
     })?;
 
+    emu.register_component(LocalFileSaveComponent::default())?;
+
     emu.init()?;
     emu.load_game(&opt.rom)?;
     if let Some(state) = opt.state {

ferretro_components/src/base/mod.rs

@@ -61,6 +61,7 @@ pub trait RetroComponent: RetroCallbacks + Any {
     fn post_load_game(&mut self, retro: &mut LibretroWrapper, rom: &Path) -> Result<()> { Ok(()) }
     fn pre_run(&mut self, retro: &mut LibretroWrapper) -> ControlFlow { ControlFlow::Continue }
     fn post_run(&mut self, retro: &mut LibretroWrapper) -> ControlFlow { ControlFlow::Continue }
+    fn pre_drop(&mut self, retro: &mut LibretroWrapper) {}
 }
 
 impl RetroComponentBase {
@@ -608,6 +609,9 @@ impl RetroCallbacks for RetroComponentBase {
 
 impl Drop for RetroComponentBase {
     fn drop(&mut self) {
+        for comp in &mut self.components {
+            comp.pre_drop(&mut self.retro);
+        }
         ferretro_base::retro::unset_handler(self.handler_id.unwrap()).unwrap();
     }
 }

ferretro_components/src/provided/stdlib/mod.rs

@@ -7,6 +7,7 @@ mod input;
 mod logs;
 mod memory;
 mod paths;
+mod saves;
 mod variables;
 
 pub use camera::CameraInfoComponent;
@@ -16,4 +17,5 @@ pub use logs::StderrCallTraceComponent;
 pub use logs::StderrLogComponent;
 pub use logs::StderrSysInfoLogComponent;
 pub use paths::PathBufComponent;
+pub use saves::LocalFileSaveComponent;
 pub use variables::VariableStoreComponent;

ferretro_components/src/provided/stdlib/saves.rs

@@ -0,0 +1,42 @@
+use std::error::Error;
+use std::fs::File;
+use std::io::{Read, Write};
+use std::path::{Path, PathBuf};
+use crate::prelude::{LibretroWrapper, RetroCallbacks, RetroComponent};
+use ferretro_base::retro::ffi::MEMORY_SAVE_RAM;
+
+#[derive(Default)]
+pub struct LocalFileSaveComponent {
+    rom_path: PathBuf,
+    initial_sram: Vec<u8>,
+}
+
+impl LocalFileSaveComponent {
+    fn save_path(&self) -> PathBuf {
+        self.rom_path.with_extension(".sav")
+    }
+}
+
+impl RetroComponent for LocalFileSaveComponent {
+    fn post_load_game(&mut self, retro: &mut LibretroWrapper, rom: &Path) -> Result<(), Box<dyn Error + Send + Sync>> {
+        self.rom_path = rom.to_path_buf();
+        let save = self.save_path();
+        if save.is_file() {
+            File::open(save)?.read(retro.mut_memory(MEMORY_SAVE_RAM))?;
+        }
+        self.initial_sram = retro.get_memory(MEMORY_SAVE_RAM).to_vec();
+        Ok(())
+    }
+
+    fn pre_drop(&mut self, retro: &mut LibretroWrapper) {
+        let final_sram = retro.get_memory(MEMORY_SAVE_RAM);
+        if &self.initial_sram != final_sram {
+            let save = self.save_path();
+            if let Ok(mut f) = File::create(save) {
+                let _ = f.write(final_sram);
+            }
+        }
+    }
+}
+
+impl RetroCallbacks for LocalFileSaveComponent {}