Tidy up some error messages

src/libretro/config/config.cpp

@@ -1370,7 +1370,7 @@ static void InitNdsSystemConfig(const NDSHeader* header, melonds::BootMode bootM
 
     if (!header && !(firmware && firmware->IsBootable())) {
         // If we're trying to boot into the NDS menu, but we didn't load bootable firmware...
-        throw bios_exception("Booting to the NDS menu requires a bootable firmware dump.");
+        throw nds_firmware_not_bootable_exception(FirmwarePath());
     }
 
     if (!firmware) {
@@ -1406,7 +1406,7 @@ static void InitNdsSystemConfig(const NDSHeader* header, melonds::BootMode bootM
 
     if (!header && (!firmware || !firmware->IsBootable() || !bios7 || !bios9)) {
         // If we're trying to boot into the NDS menu, but we don't have all the required files...
-        throw bios_exception("Booting to the NDS menu requires native NDS BIOS files and bootable firmware.");
+        throw nds_sysfiles_incomplete_exception();
     }
 
     if (bios7 && bios9) {
@@ -1477,17 +1477,21 @@ static void InitDsiSystemConfig() {
     retro_assert(firmwarePath.has_value());
     // If we couldn't get the system directory, we wouldn't have gotten this far
 
+    if (firmwareName == melonds::config::values::NOT_FOUND) {
+        throw dsi_no_firmware_found_exception();
+    }
+
     unique_ptr<SPI_Firmware::Firmware> firmware = LoadFirmware(*firmwarePath);
+    if (!firmware) {
+        throw firmware_missing_exception(firmwareName);
+    }
+
     if (firmware && firmware->Header().ConsoleType != SPI_Firmware::FirmwareConsoleType::DSi) {
         retro::warn("Expected firmware of type DSi, got %s", ConsoleTypeName(firmware->Header().ConsoleType).data());
-        firmware = nullptr;
+        throw wrong_firmware_type_exception(firmwareName, melonds::ConsoleType::DSi, firmware->Header().ConsoleType);
     }
     // DSi firmware isn't bootable, so we don't need to check for that here.
 
-    if (!firmware) {
-        throw bios_exception("Failed to load DSi BIOS file");
-    }
-
     memcpy(DSi::ARM9iBIOS, bios9i.get(), sizeof(DSi::ARM9iBIOS));
     memcpy(DSi::ARM7iBIOS, bios7i.get(), sizeof(DSi::ARM7iBIOS));
     memcpy(NDS::ARM7BIOS, bios7.get(), sizeof(NDS::ARM7BIOS));

src/libretro/exceptions.cpp

@@ -25,6 +25,75 @@ using std::optional;
 using std::string;
 using std::string_view;
 
+melonds::nds_firmware_not_bootable_exception::nds_firmware_not_bootable_exception(string_view firmwareName) noexcept
+    : bios_exception(
+    fmt::format(
+        FMT_STRING(
+            "The firmware file at \"{}\" can't be used to boot to the DS menu."
+        ),
+        firmwareName
+    ),
+    "Ensure you have native DS (not DSi) firmware in your frontend's system folder. "
+    "Pick it in the core options, then restart the core. "
+    "If you just want to play a DS game, try setting Boot Mode to \"Direct\" "
+    "or BIOS/Firmware Mode to \"Built-In\" in the core options."
+) {
+}
+
+melonds::wrong_firmware_type_exception::wrong_firmware_type_exception(
+    std::string_view firmwareName,
+    melonds::ConsoleType consoleType,
+    SPI_Firmware::FirmwareConsoleType firmwareConsoleType
+) noexcept : bios_exception(
+    fmt::format(
+        FMT_STRING("The firmware file at \"{}\" is for the {}, but it can't be used in {} mode."),
+        firmwareName,
+        firmwareConsoleType,
+        consoleType
+    ),
+    fmt::format(
+        FMT_STRING(
+            "Ensure you have a {}-compatible firmware file in your frontend's system folder (any name works). "
+            "Pick it in the core options, then restart the core. "
+            "If you just want to play a DS game, try disabling DSi mode in the core options."
+        ),
+        consoleType
+    )
+) {
+}
+
+melonds::dsi_no_firmware_found_exception::dsi_no_firmware_found_exception() noexcept
+    : bios_exception(
+    "DSi mode requires a native firmware file, but none could be found.",
+    "Place your DSi firmware file in your frontend's system folder (any name works), then restart the core. "
+    "If you want to play a regular DS game, try disabling DSi mode in the core options."
+) {
+}
+
+melonds::firmware_missing_exception::firmware_missing_exception(std::string_view firmwareName) noexcept
+    : bios_exception(
+    fmt::format(
+        FMT_STRING("The core is set to use the firmware file at \"{}\", but it wasn't there or it couldn't be loaded."),
+        firmwareName),
+    fmt::format(
+        FMT_STRING(
+            "Place your DSi firmware file in your frontend's system folder, name it \"{}\", then restart the core."
+        ),
+        firmwareName
+    )
+) {
+}
+
+melonds::nds_sysfiles_incomplete_exception::nds_sysfiles_incomplete_exception() noexcept
+: bios_exception(
+    "Booting to the native DS menu requires native DS firmware and BIOS files, "
+    "but some of them were missing or couldn't be loaded.",
+    "Place your DS system files in your frontend's system folder, then restart the core. "
+    "If you want to play a regular DS game, try setting Boot Mode to \"Direct\" "
+    "and BIOS/Firmware Mode to \"Built-In\" in the core options."
+) {
+}
+
 melonds::dsi_missing_bios_exception::dsi_missing_bios_exception(melonds::BiosType bios, string_view biosName) noexcept
     : bios_exception(
     fmt::format(FMT_STRING("DSi mode requires the {} BIOS file, but none was found."), bios),
@@ -48,9 +117,12 @@ melonds::dsi_no_nand_found_exception::dsi_no_nand_found_exception() noexcept
 ) {
 
 }
+
 melonds::dsi_nand_missing_exception::dsi_nand_missing_exception(string_view nandName) noexcept
     : bios_exception(
-    fmt::format(FMT_STRING("The core is set to use the NAND file at \"{}\", but it wasn't there or it couldn't be loaded."), nandName),
+    fmt::format(
+        FMT_STRING("The core is set to use the NAND file at \"{}\", but it wasn't there or it couldn't be loaded."),
+        nandName),
     fmt::format(
         FMT_STRING("Place your NAND file in your frontend's system folder, name it \"{}\", then restart the core."),
         nandName

src/libretro/exceptions.hpp

@@ -68,6 +68,36 @@ namespace melonds
         using config_exception::config_exception;
     };
 
+    class dsi_no_firmware_found_exception : public bios_exception {
+    public:
+        dsi_no_firmware_found_exception() noexcept;
+    };
+
+    class firmware_missing_exception : public bios_exception {
+    public:
+        firmware_missing_exception(std::string_view firmwareName) noexcept;
+    };
+
+    class wrong_firmware_type_exception: public bios_exception {
+    public:
+        wrong_firmware_type_exception(
+            std::string_view  firmwareName,
+            melonds::ConsoleType consoleType,
+            SPI_Firmware::FirmwareConsoleType firmwareConsoleType
+        ) noexcept;
+    };
+
+    class nds_firmware_not_bootable_exception : public bios_exception {
+    public:
+        explicit nds_firmware_not_bootable_exception(std::string_view firmwareName) noexcept;
+    };
+
+
+    class nds_sysfiles_incomplete_exception : public bios_exception {
+    public:
+        explicit nds_sysfiles_incomplete_exception() noexcept;
+    };
+
     /// Thrown when attempting to load a required BIOS file that is missing.
     class dsi_missing_bios_exception : public bios_exception {
     public: