actually load multiple separate instances of the core (OS will deduplicate by path)

ferretro_base/Cargo.toml

@@ -11,4 +11,4 @@ cc = "^1"
 libretro-sys = "0.1"
 libloading = "0.5"
 num_enum = "0.4"
-once_cell = "1.8"
+once_cell = "1"

ferretro_components/Cargo.toml

@@ -15,6 +15,7 @@ ffmpeg-next = { version = "4.3.8", optional = true }
 sdl2 = { version = "0.32", optional = true, features = ["gfx"] }
 gl = { version = "0.14", optional = true }
 crossbeam-channel = { version = "0.4", optional = true }
+tempfile = "3"
 
 [dev-dependencies]
 crossbeam-channel = "0.4"

ferretro_components/src/base/mod.rs

@@ -4,6 +4,7 @@
 
 use crate::prelude::*;
 use ferretro_base::retro::ffi::*;
+use ferretro_base::prelude::{LibretroWrapperAccess, RetroHandlerId};
 
 use core::any::{Any, TypeId};
 use core::pin::Pin;
@@ -13,7 +14,6 @@ use std::path::{PathBuf, Path};
 use std::io::Read;
 use std::collections::HashMap;
 use std::ffi::c_void;
-use ferretro_base::prelude::{LibretroWrapperAccess, RetroHandlerId};
 
 pub struct RetroComponentBase {
     retro: LibretroWrapper,
@@ -37,6 +37,7 @@ pub struct RetroComponentBase {
     cached_geometry: Option<GameGeometry>,
 
     handler_id: Option<RetroHandlerId>,
+    _temp_dir: tempfile::TempDir,
 }
 
 // TODO: replace with std::ops::ControlFlow when it becomes stable
@@ -61,13 +62,18 @@ pub trait RetroComponent: RetroCallbacks + Any {
 impl RetroComponentBase {
     // TODO: constructor & wrapper that uses a statically linked libretro?
     pub fn new(core_path: impl AsRef<Path>) -> Pin<Box<Self>> {
-        let lib = libloading::Library::new(core_path.as_ref()).unwrap();
+        // allow multiple copies of same lib, possibly?
+        let temp_dir = tempfile::tempdir().unwrap();
+        let libretro_path = temp_dir.path().join(core_path.as_ref().file_name().unwrap());
+        std::fs::copy(core_path.as_ref(), &libretro_path).unwrap();
+
+        let lib = libloading::Library::new(&libretro_path).unwrap();
         let raw_retro = ferretro_base::retro::loading::LibretroApi::from_library(lib).unwrap();
         let retro = LibretroWrapper::from(raw_retro);
 
         let emu = RetroComponentBase {
             retro,
-            libretro_path: core_path.as_ref().to_path_buf(),
+            libretro_path,
             components: Default::default(),
             component_ptrs: Default::default(),
             cached_rom_path: None,
@@ -82,6 +88,7 @@ impl RetroComponentBase {
             cached_memory_map: None,
             cached_geometry: None,
             handler_id: None,
+            _temp_dir: temp_dir,
         };
 
         let mut pin_emu = Box::pin(emu);