[gnome-games] retro: Add RetroFirmware object

[Alexander Mikhaylenko <alexm src gnome org>]

commit cfa8806403fda5e896dd974cbe1acd9f3ff7b444
Author: Adwait Rawat <adwait rawat gmail com>
Date:   Mon Jun 22 21:00:55 2020 +0900

    retro: Add RetroFirmware object

 src/meson.build               |  1 +
 src/retro/retro-firmware.vala | 57 +++++++++++++++++++++++++++++++++++++++++++
 2 files changed, 58 insertions(+)
---
diff --git a/src/meson.build b/src/meson.build
index 4db4c265..8cd6e8c8 100644
--- a/src/meson.build
+++ b/src/meson.build
@@ -84,6 +84,7 @@ vala_sources = [
   'retro/retro-core-manager.vala',
   'retro/retro-core-source.vala',
   'retro/retro-error.vala',
+  'retro/retro-firmware.vala',
   'retro/retro-gamepad.vala',
   'retro/retro-input-manager.vala',
   'retro/retro-options.vala',
diff --git a/src/retro/retro-firmware.vala b/src/retro/retro-firmware.vala
new file mode 100644
index 00000000..a4b00716
--- /dev/null
+++ b/src/retro/retro-firmware.vala
@@ -0,0 +1,57 @@
+// This file is part of GNOME Games. License: GPL-3.0+.
+
+public class Games.RetroFirmware : Object, Firmware {
+       private string name;
+       private bool is_mandatory;
+       private string path;
+       private string? md5;
+       private string? sha512;
+
+       public RetroFirmware (string name, Retro.CoreDescriptor core_descriptor) throws Error {
+               this.name = name;
+
+               if (core_descriptor.has_firmware_md5 (name))
+                       md5 = core_descriptor.get_firmware_md5 (name);
+               if (core_descriptor.has_firmware_sha512 (name))
+                       sha512 = core_descriptor.get_firmware_sha512 (name);
+
+               is_mandatory = core_descriptor.get_is_firmware_mandatory (name);
+               path = core_descriptor.get_firmware_path (name);
+       }
+
+       public bool get_is_mandatory () {
+               return is_mandatory;
+       }
+
+       public void check_is_valid (Platform platform) throws FirmwareError {
+               var firmware_dir = File.new_for_path (platform.get_system_dir ());
+
+               var firmware = firmware_dir.get_child (path);
+               if (!firmware.query_exists ())
+                       throw new FirmwareError.FIRMWARE_NOT_FOUND ("This game requires the %s firmware file 
to run.", firmware.get_path ());
+
+               if (md5 == null && sha512 == null)
+                       return;
+
+               try {
+                       var stream = firmware.read ();
+
+                       stream.seek (0, SeekType.END);
+                       var size = (size_t) stream.tell ();
+                       stream.seek (0, SeekType.SET);
+                       var bytes = stream.read_bytes (size);
+
+                       if (md5 != null) {
+                               if (Checksum.compute_for_bytes (ChecksumType.MD5, bytes) != md5)
+                                       throw new FirmwareError.FIRMWARE_NOT_FOUND ("This game requires the 
%s firmware file with a MD5 fingerprint of %s to run.", firmware.get_path (), md5);
+                       }
+
+                       if (sha512 != null) {
+                               if (Checksum.compute_for_bytes (ChecksumType.SHA512, bytes) != sha512)
+                                       throw new FirmwareError.FIRMWARE_NOT_FOUND ("This game requires the 
%s firmware file with a SHA-512 fingerprint of %s to run.", firmware.get_path (), sha512);
+                       }
+               } catch (Error e) {
+                       throw new FirmwareError.FIRMWARE_NOT_FOUND (e.message);
+               }
+       }
+}