From af2df788097eb7a6480f99c33b9ae69158f9c2f6 Mon Sep 17 00:00:00 2001
From: Simon Gellis <simongellis@gmail.com>
Date: Wed, 6 Aug 2025 23:31:32 -0400
Subject: [PATCH] Move cart to separate file

---
 src/emulator.rs      | 62 +++++--------------------------------------
 src/emulator/cart.rs | 63 ++++++++++++++++++++++++++++++++++++++++++++
 2 files changed, 69 insertions(+), 56 deletions(-)
 create mode 100644 src/emulator/cart.rs

diff --git a/src/emulator.rs b/src/emulator.rs
index 55019ec..d73b276 100644
--- a/src/emulator.rs
+++ b/src/emulator.rs
@@ -1,8 +1,6 @@
 use std::{
     collections::HashMap,
     fmt::Display,
-    fs::{self, File},
-    io::{Read, Seek, SeekFrom, Write},
     path::{Path, PathBuf},
     sync::{
         Arc, Weak,
@@ -16,11 +14,11 @@ use anyhow::Result;
 use atomic::Atomic;
 use bytemuck::NoUninit;
 use egui_notify::Toast;
-use rand::Rng;
 use tracing::{error, warn};
 
 use crate::{
     audio::Audio,
+    emulator::cart::Cart,
     graphics::TextureSink,
     memory::{MemoryRange, MemoryRegion},
 };
@@ -28,6 +26,7 @@ use shrooms_vb_core::{EXPECTED_FRAME_SIZE, Sim, StopReason};
 pub use shrooms_vb_core::{VBKey, VBRegister, VBWatchpointType};
 
 mod address_set;
+mod cart;
 mod shrooms_vb_core;
 
 #[derive(PartialEq, Eq, Hash, Clone, Copy, Debug)]
@@ -62,54 +61,6 @@ impl Display for SimId {
     }
 }
 
-struct Cart {
-    rom_path: PathBuf,
-    rom: Vec<u8>,
-    sram_file: File,
-    sram: Vec<u8>,
-}
-
-impl Cart {
-    fn load(rom_path: &Path, sim_id: SimId) -> Result<Self> {
-        let rom = fs::read(rom_path)?;
-
-        let mut sram_file = File::options()
-            .read(true)
-            .write(true)
-            .create(true)
-            .truncate(false)
-            .open(sram_path(rom_path, sim_id))?;
-
-        let sram = if sram_file.metadata()?.len() == 0 {
-            // new SRAM file, randomize the contents
-            let mut sram = vec![0; 8 * 1024];
-            let mut rng = rand::rng();
-            for dst in sram.iter_mut().step_by(2) {
-                *dst = rng.random();
-            }
-            sram
-        } else {
-            let mut sram = Vec::with_capacity(8 * 1024);
-            sram_file.read_to_end(&mut sram)?;
-            sram
-        };
-
-        Ok(Cart {
-            rom_path: rom_path.to_path_buf(),
-            rom,
-            sram_file,
-            sram,
-        })
-    }
-}
-
-fn sram_path(rom_path: &Path, sim_id: SimId) -> PathBuf {
-    match sim_id {
-        SimId::Player1 => rom_path.with_extension("p1.sram"),
-        SimId::Player2 => rom_path.with_extension("p2.sram"),
-    }
-}
-
 pub struct EmulatorBuilder {
     rom: Option<PathBuf>,
     commands: mpsc::Receiver<EmulatorCommand>,
@@ -231,12 +182,12 @@ impl Emulator {
     }
 
     pub fn start_second_sim(&mut self, rom: Option<PathBuf>) -> Result<()> {
-        let rom_path = if let Some(path) = rom {
+        let file_path = if let Some(path) = rom {
             Some(path)
         } else {
-            self.carts[0].as_ref().map(|c| c.rom_path.clone())
+            self.carts[0].as_ref().map(|c| c.file_path.clone())
         };
-        let cart = match rom_path {
+        let cart = match file_path {
             Some(rom_path) => Some(Cart::load(&rom_path, SimId::Player2)?),
             None => None,
         };
@@ -349,8 +300,7 @@ impl Emulator {
         let cart = self.carts[sim_id.to_index()].as_mut();
         if let (Some(sim), Some(cart)) = (sim, cart) {
             sim.read_sram(&mut cart.sram);
-            cart.sram_file.seek(SeekFrom::Start(0))?;
-            cart.sram_file.write_all(&cart.sram)?;
+            cart.save_sram()?;
         }
         Ok(())
     }
diff --git a/src/emulator/cart.rs b/src/emulator/cart.rs
new file mode 100644
index 0000000..55cc134
--- /dev/null
+++ b/src/emulator/cart.rs
@@ -0,0 +1,63 @@
+use anyhow::Result;
+use rand::Rng;
+use std::{
+    fs::{self, File},
+    io::{Read, Seek as _, SeekFrom, Write as _},
+    path::{Path, PathBuf},
+};
+
+use crate::emulator::SimId;
+
+pub struct Cart {
+    pub file_path: PathBuf,
+    pub rom: Vec<u8>,
+    sram_file: File,
+    pub sram: Vec<u8>,
+}
+
+impl Cart {
+    pub fn load(file_path: &Path, sim_id: SimId) -> Result<Self> {
+        let rom = fs::read(file_path)?;
+
+        let mut sram_file = File::options()
+            .read(true)
+            .write(true)
+            .create(true)
+            .truncate(false)
+            .open(sram_path(file_path, sim_id))?;
+
+        let sram = if sram_file.metadata()?.len() == 0 {
+            // new SRAM file, randomize the contents
+            let mut sram = vec![0; 8 * 1024];
+            let mut rng = rand::rng();
+            for dst in sram.iter_mut().step_by(2) {
+                *dst = rng.random();
+            }
+            sram
+        } else {
+            let mut sram = Vec::with_capacity(8 * 1024);
+            sram_file.read_to_end(&mut sram)?;
+            sram
+        };
+
+        Ok(Cart {
+            file_path: file_path.to_path_buf(),
+            rom,
+            sram_file,
+            sram,
+        })
+    }
+
+    pub fn save_sram(&mut self) -> Result<()> {
+        self.sram_file.seek(SeekFrom::Start(0))?;
+        self.sram_file.write_all(&self.sram)?;
+        Ok(())
+    }
+}
+
+fn sram_path(file_path: &Path, sim_id: SimId) -> PathBuf {
+    match sim_id {
+        SimId::Player1 => file_path.with_extension("p1.sram"),
+        SimId::Player2 => file_path.with_extension("p2.sram"),
+    }
+}