Restructure error handling

Most recoverable errors have been modified to trigger appropriate message
dialogs instead of panics. Other `.expect()`s have been left with annotations
about why they shouldn't fail.

Author: kelpsyberry

core/build.rs

@@ -915,7 +915,7 @@ mod disasm {
                     Instr::Mrc => write!(file, "mrc_mcr::<true>"),
                     Instr::Swi => write!(file, "swi"),
                     Instr::Undefined { .. } => write!(file, "undefined"),
-                    oops => unreachable!("{:?}", oops),
+                    _ => unreachable!(),
                 }?;
                 write!(file, ",")?;
             }

core/src/audio/channel.rs

@@ -247,6 +247,7 @@ impl Channel {
     }
 
     #[inline]
+    #[allow(clippy::unused_self)]
     fn check_loop_start(&self) {
         #[cfg(feature = "log")]
         if self.control.running() && self.format == Format::Adpcm && self.loop_start == 0 {
@@ -255,6 +256,7 @@ impl Channel {
     }
 
     #[inline]
+    #[allow(clippy::unused_self)]
     fn check_total_size(&self) {
         #[cfg(feature = "log")]
         if self.control.running()

core/src/audio/io.rs

@@ -2,6 +2,7 @@ use super::{capture, channel, Audio, Control};
 use crate::cpu::bus::AccessType;
 
 impl Audio {
+    #[allow(clippy::extra_unused_type_parameters)]
     pub(crate) fn read_8<A: AccessType>(&mut self, addr: u32) -> u8 {
         if addr & 0x100 == 0 {
             let channel = &self.channels[addr as usize >> 4 & 0xF];
@@ -51,6 +52,7 @@ impl Audio {
         0
     }
 
+    #[allow(clippy::extra_unused_type_parameters)]
     pub(crate) fn read_16<A: AccessType>(&mut self, addr: u32) -> u16 {
         if addr & 0x100 == 0 {
             let channel = &self.channels[addr as usize >> 4 & 0xF];
@@ -91,6 +93,7 @@ impl Audio {
         0
     }
 
+    #[allow(clippy::extra_unused_type_parameters)]
     pub(crate) fn read_32<A: AccessType>(&mut self, addr: u32) -> u32 {
         if addr & 0x100 == 0 {
             let channel = &self.channels[addr as usize >> 4 & 0xF];
@@ -122,6 +125,7 @@ impl Audio {
         0
     }
 
+    #[allow(clippy::extra_unused_type_parameters)]
     pub(crate) fn write_8<A: AccessType>(&mut self, addr: u32, value: u8) {
         if addr & 0x100 == 0 {
             let i = addr as usize >> 4 & 0xF;
@@ -253,6 +257,7 @@ impl Audio {
         }
     }
 
+    #[allow(clippy::extra_unused_type_parameters)]
     pub(crate) fn write_16<A: AccessType>(&mut self, addr: u32, value: u16) {
         if addr & 0x100 == 0 {
             let i = addr as usize >> 4 & 0xF;
@@ -332,6 +337,7 @@ impl Audio {
         }
     }
 
+    #[allow(clippy::extra_unused_type_parameters)]
     pub(crate) fn write_32<A: AccessType>(&mut self, addr: u32, value: u32) {
         if addr & 0x100 == 0 {
             let i = addr as usize >> 4 & 0xF;

core/src/ds_slot/rom.rs

@@ -6,7 +6,10 @@ pub mod icon;
 pub mod normal;
 
 use super::RomOutputLen;
-use crate::utils::{BoxedByteSlice, ByteMutSlice, Bytes, Savestate};
+use crate::{
+    utils::{BoxedByteSlice, ByteMutSlice, Bytes, Savestate},
+    Model,
+};
 
 #[allow(clippy::len_without_is_empty)]
 pub trait Contents {
@@ -112,3 +115,14 @@ impl Rom {
 }
 
 impl_from_variants!(Rom; Normal, Empty; normal::Normal, Empty);
+
+pub fn min_size_for_model(model: Model) -> usize {
+    match model {
+        Model::Ds | Model::Lite | Model::Ique | Model::IqueLite => 0x200,
+        Model::Dsi => 0x1000,
+    }
+}
+
+pub fn is_valid_size(len: usize, model: Model) -> bool {
+    len.is_power_of_two() && len >= min_size_for_model(model)
+}

core/src/ds_slot/rom/icon.rs

@@ -2,9 +2,12 @@ use super::Contents;
 use crate::utils::Bytes;
 
 #[inline]
-pub fn decode(offset: u32, rom_contents: &mut impl Contents) -> Option<[u32; 32 * 32]> {
+pub fn decode(offset: usize, rom_contents: &mut impl Contents) -> Option<[u32; 32 * 32]> {
     let mut icon_data = Bytes::new([0; 0x220]);
-    rom_contents.read_slice(offset as usize, icon_data.as_byte_mut_slice());
+    if offset + 0x220 > rom_contents.len() {
+        return None;
+    }
+    rom_contents.read_slice(offset, icon_data.as_byte_mut_slice());
 
     let mut palette = [0; 16];
     for (i, color) in palette.iter_mut().enumerate().skip(1) {

core/src/ds_slot/rom/normal.rs

@@ -1,23 +1,13 @@
-use super::{super::RomOutputLen, key1, Contents};
+use super::{super::RomOutputLen, is_valid_size, key1, Contents};
 use crate::{
     cpu::arm7,
     utils::{make_zero, zero, ByteMutSlice, Bytes, Savestate},
+    Model,
 };
-use core::fmt;
 
 #[derive(Clone, Copy, Debug, PartialEq, Eq)]
 pub enum CreationError {
-    SizeNotPowerOfTwo,
-    SizeTooSmall,
-}
-
-impl fmt::Display for CreationError {
-    fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
-        match self {
-            CreationError::SizeNotPowerOfTwo => f.write_str("ROM size not power of 2"),
-            CreationError::SizeTooSmall => f.write_str("ROM size too small"),
-        }
-    }
+    InvalidSize,
 }
 
 #[derive(Clone, Copy, PartialEq, Eq, Savestate)]
@@ -47,19 +37,17 @@ pub struct Normal {
 
 impl Normal {
     /// # Errors
-    /// - [`CreationError::SizeNotPowerOfTwo`](CreationError::SizeNotPowerOfTwo): the ROM contents'
-    ///   size is not a power of two.
+    /// - [`CreationError::InvalidSize`](CreationError::InvalidSize): the ROM contents' size is
+    ///   either not a power of two or too small.
     pub fn new(
         contents: Box<dyn Contents>,
         arm7_bios: Option<&Bytes<{ arm7::BIOS_SIZE }>>,
+        model: Model,
         #[cfg(feature = "log")] logger: slog::Logger,
     ) -> Result<Self, CreationError> {
         let len = contents.len();
-        if !len.is_power_of_two() {
-            return Err(CreationError::SizeNotPowerOfTwo);
-        }
-        if len < 0x200 {
-            return Err(CreationError::SizeTooSmall);
+        if !is_valid_size(len, model) {
+            return Err(CreationError::InvalidSize);
         }
         let rom_mask = (len - 1) as u32;
         let chip_id = 0x0000_00C2
@@ -160,7 +148,10 @@ impl super::RomDevice for Normal {
             let Some(mut secure_area) = self.contents.secure_area_mut() else {
                 return Ok(());
             };
-            let key_buf = self.key_buf.as_ref().unwrap();
+            let key_buf = self
+                .key_buf
+                .as_ref()
+                .expect("key_buf should be initialized");
             if secure_area.read_le::<u64>(0) == 0xE7FF_DEFF_E7FF_DEFF {
                 secure_area[..8].copy_from_slice(b"encryObj");
                 let level_3_key_buf = key_buf.level_3::<2>();
@@ -244,7 +235,7 @@ impl super::RomDevice for Normal {
                     let res = self
                         .key_buf
                         .as_ref()
-                        .unwrap()
+                        .expect("key_buf should be initialized")
                         .decrypt_64_bit([cmd.read_be(4), cmd.read_be(0)]);
                     cmd.write_be(4, res[0]);
                     cmd.write_be(0, res[1]);

core/src/ds_slot/spi/eeprom_4k.rs

@@ -41,7 +41,7 @@ pub struct Eeprom4k {
 
 #[derive(Clone, Copy, Debug, PartialEq, Eq)]
 pub enum CreationError {
-    IncorrectSize,
+    InvalidSize,
 }
 
 impl Eeprom4k {
@@ -51,7 +51,7 @@ impl Eeprom4k {
         #[cfg(feature = "log")] logger: slog::Logger,
     ) -> Result<Self, CreationError> {
         if contents.len() != 512 {
-            return Err(CreationError::IncorrectSize);
+            return Err(CreationError::InvalidSize);
         }
         let mut result = Eeprom4k {
             #[cfg(feature = "log")]

core/src/ds_slot/spi/eeprom_fram.rs

@@ -51,7 +51,7 @@ pub struct EepromFram {
 
 #[derive(Clone, Copy, Debug, PartialEq, Eq)]
 pub enum CreationError {
-    IncorrectSize,
+    InvalidSize,
 }
 
 pub enum CreationContents {}
@@ -63,7 +63,7 @@ impl EepromFram {
         #[cfg(feature = "log")] logger: slog::Logger,
     ) -> Result<Self, CreationError> {
         if !matches!(contents.len(), 0x2000 | 0x1_0000 | 0x2_0000) {
-            return Err(CreationError::IncorrectSize);
+            return Err(CreationError::InvalidSize);
         }
         let contents_len_mask = (contents.len() - 1) as u32;
         let page_mask = match contents.len().trailing_zeros() {

core/src/ds_slot/spi/flash.rs

@@ -17,7 +17,7 @@ pub struct Flash {
 
 #[derive(Clone, Copy, Debug, PartialEq, Eq)]
 pub enum CreationError {
-    IncorrectSize,
+    InvalidSize,
 }
 
 pub enum CreationContents {}
@@ -30,7 +30,7 @@ impl Flash {
         #[cfg(feature = "log")] logger: slog::Logger,
     ) -> Result<Self, CreationError> {
         if !matches!(contents.len(), 0x4_0000 | 0x8_0000 | 0x10_0000) {
-            return Err(CreationError::IncorrectSize);
+            return Err(CreationError::InvalidSize);
         }
         Ok(Flash {
             contents: flash::Flash::new(
@@ -39,7 +39,8 @@ impl Flash {
                 #[cfg(feature = "log")]
                 logger.new(slog::o!("contents" => "")),
             )
-            .unwrap(),
+            // NOTE: The contents' length was just checked above, this should never occur.
+            .expect("Couldn't create SPI FLASH device"),
             has_ir,
             ir_cmd: 0,
             first_ir_data_byte: false,

core/src/emu.rs

@@ -28,11 +28,9 @@ use crate::{
     wifi::WiFi,
     Model,
 };
-use core::fmt;
 #[cfg(feature = "xq-audio")]
 use core::num::NonZeroU32;
 use input::Input;
-use std::error::Error;
 use swram::Swram;
 
 proc_bitfield::bitfield! {
@@ -193,26 +191,6 @@ pub enum BuildError {
     RomNeedsDecryptionButNoBiosProvided,
 }
 
-impl Error for BuildError {}
-
-impl fmt::Display for BuildError {
-    fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
-        match self {
-            BuildError::MissingSysFiles => f.write_str("missing system files"),
-            BuildError::RomCreation(e) => write!(f, "ROM creation error: {e}"),
-            BuildError::RomNeedsDecryptionButNoBiosProvided => {
-                f.write_str("ROM needs decryption, but no original ARM7 BIOS provided")
-            }
-        }
-    }
-}
-
-impl fmt::Debug for BuildError {
-    fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
-        <Self as fmt::Display>::fmt(self, f)
-    }
-}
-
 impl Builder {
     #[inline]
     #[allow(clippy::too_many_arguments)]
@@ -273,6 +251,7 @@ impl Builder {
                 ds_slot::rom::normal::Normal::new(
                     contents,
                     self.arm7_bios.as_deref(),
+                    self.model,
                     #[cfg(feature = "log")]
                     self.logger.new(slog::o!("ds_rom" => "normal")),
                 )
@@ -402,7 +381,8 @@ impl<E: cpu::Engine> Emu<E> {
         let mut header_bytes = Bytes::new([0; 0x170]);
         self.ds_slot.rom.read_header(&mut header_bytes);
         let header = ds_slot::rom::header::Header::new(header_bytes.as_byte_slice())
-            .expect("invalid ROM header");
+            // NOTE: The ROM file's size is ensured beforehand, this should never occur.
+            .expect("Couldn't read DS slot ROM header");
         let chip_id = self.ds_slot.rom.chip_id();
 
         macro_rules! write_main_mem {

core/src/flash.rs

@@ -42,7 +42,7 @@ pub struct Flash {
 
 #[derive(Clone, Copy, Debug, PartialEq, Eq)]
 pub enum CreationError {
-    SizeNotPowerOfTwo,
+    InvalidSize,
 }
 
 impl Flash {
@@ -51,8 +51,8 @@ impl Flash {
         id: [u8; 20],
         #[cfg(feature = "log")] logger: slog::Logger,
     ) -> Result<Self, CreationError> {
-        if !contents.len().is_power_of_two() || contents.len() < 0x4_0000 {
-            return Err(CreationError::SizeNotPowerOfTwo);
+        if !contents.len().is_power_of_two() || contents.len() < 0x2_0000 {
+            return Err(CreationError::InvalidSize);
         }
         let contents_len_mask = (contents.len() - 1) as u32;
         Ok(Flash {

core/src/gpu/engine_2d/io.rs

@@ -5,6 +5,7 @@ use super::{
 use crate::cpu::bus::AccessType;
 
 impl<R: Role> Engine2d<R> {
+    #[allow(clippy::extra_unused_type_parameters)]
     pub(crate) fn read_8<A: AccessType>(&mut self, addr: u32) -> u8 {
         let addr = addr & 0x7F;
         match addr {
@@ -34,6 +35,7 @@ impl<R: Role> Engine2d<R> {
         }
     }
 
+    #[allow(clippy::extra_unused_type_parameters)]
     pub(crate) fn read_16<A: AccessType>(&mut self, addr: u32) -> u16 {
         let addr = addr & 0x7E;
         match addr {
@@ -60,6 +62,7 @@ impl<R: Role> Engine2d<R> {
         }
     }
 
+    #[allow(clippy::extra_unused_type_parameters)]
     pub(crate) fn read_32<A: AccessType>(&mut self, addr: u32) -> u32 {
         let addr = addr & 0x7C;
         match addr {
@@ -85,6 +88,7 @@ impl<R: Role> Engine2d<R> {
         }
     }
 
+    #[allow(clippy::extra_unused_type_parameters)]
     pub(crate) fn write_8<A: AccessType>(&mut self, addr: u32, value: u8) {
         let addr = addr & 0x7F;
         match addr {
@@ -201,6 +205,7 @@ impl<R: Role> Engine2d<R> {
         }
     }
 
+    #[allow(clippy::extra_unused_type_parameters)]
     pub(crate) fn write_16<A: AccessType>(&mut self, addr: u32, value: u16) {
         let addr = addr & 0x7E;
         match addr {
@@ -311,6 +316,7 @@ impl<R: Role> Engine2d<R> {
         }
     }
 
+    #[allow(clippy::extra_unused_type_parameters)]
     pub(crate) fn write_32<A: AccessType>(&mut self, addr: u32, value: u32) {
         let addr = addr & 0x7C;
         match addr {

core/src/gpu/engine_3d.rs

@@ -576,6 +576,7 @@ impl Engine3d {
     }
 
     #[inline]
+    #[allow(clippy::unused_self, clippy::let_and_return)]
     fn params_for_command(&self, command: u8) -> u8 {
         let result = CMD_PARAMS[command as usize];
         #[cfg(feature = "log")]