Add feature flag to disable the gamedb

src/BizHawk.Emulation.Common/Database/Database.cs

@@ -187,6 +187,10 @@ namespace BizHawk.Emulation.Common
 
 		public static GameInfo CheckDatabase(string hash)
 		{
+#if BIZHAWKBUILD_GAMEDB_ALWAYS_MISS
+			_ = hash;
+			return null;
+#else
 			_acquire.WaitOne();
 
 			var hashFormatted = FormatHash(hash);
@@ -198,13 +202,16 @@ namespace BizHawk.Emulation.Common
 			}
 
 			return new GameInfo(cgi);
+#endif
 		}
 
 		public static GameInfo GetGameInfo(byte[] romData, string fileName)
 		{
+			var hashSHA1 = SHA1Checksum.ComputeDigestHex(romData);
+
+#if !BIZHAWKBUILD_GAMEDB_ALWAYS_MISS
 			_acquire.WaitOne();
 
-			var hashSHA1 = SHA1Checksum.ComputeDigestHex(romData);
 			if (DB.TryGetValue(hashSHA1, out var cgi))
 			{
 				return new GameInfo(cgi);
@@ -221,6 +228,7 @@ namespace BizHawk.Emulation.Common
 			{
 				return new GameInfo(cgi);
 			}
+#endif
 
 			// rom is not in database. make some best-guesses
 			var game = new GameInfo
@@ -230,7 +238,9 @@ namespace BizHawk.Emulation.Common
 				NotInDatabase = true
 			};
 
+#if !BIZHAWKBUILD_GAMEDB_ALWAYS_MISS
 			Console.WriteLine($"Game was not in DB. CRC: {hashCRC32} MD5: {hashMD5}");
+#endif
 
 			var ext = Path.GetExtension(fileName)?.ToUpperInvariant();
 

src/BizHawk.Emulation.Cores/Arcades/MAME/MAMEMachineDB.cs

@@ -51,11 +51,16 @@ namespace BizHawk.Emulation.Cores.Arcades.MAME
 
 		public static bool IsMAMEMachine(string path)
 		{
+#if BIZHAWKBUILD_GAMEDB_ALWAYS_MISS
+			_ = path;
+			return false;
+#else
 			if (_acquire == null) throw new InvalidOperationException("MAME Machine DB not initialized. It's a client responsibility because only a client knows where the database is located.");
 			if (HawkFile.PathContainsPipe(path)) return false; // binded archive, can't be a mame zip (note | is not a legal filesystem char, at least on windows)
 			if (Path.GetExtension(path).ToLowerInvariant() is not ".zip" and not ".7z") return false;
 			_acquire.WaitOne();
 			return Instance.MachineDB.Contains(Path.GetFileNameWithoutExtension(path).ToLowerInvariant());
+#endif
 		}
 	}
 }

src/BizHawk.Emulation.Cores/Consoles/Nintendo/NES/BootGodDB.cs

@@ -151,9 +151,14 @@ namespace BizHawk.Emulation.Cores.Nintendo.NES
 
 		public static List<CartInfo> Identify(string sha1)
 		{
+#if BIZHAWKBUILD_GAMEDB_ALWAYS_MISS
+			_ = sha1;
+			return new(capacity: 0);
+#else
 			if (acquire == null) throw new InvalidOperationException("Bootgod DB not initialized. It's a client responsibility because only a client knows where the database is located.");
 			acquire.WaitOne();
 			return instance._sha1Table[sha1];
+#endif
 		}
 	}
 }