BizHawkClient: Add command to get size of memory domain (#4439)

* Mega Man 2: Remove mm2 commands from client if rom size too small

data/lua/connector_bizhawk_generic.lua

@@ -121,6 +121,14 @@ Response:
 
     Expected Response Type: `HASH_RESPONSE`
 
+- `MEMORY_SIZE`  
+    Returns the size in bytes of the specified memory domain.
+
+    Expected Response Type: `MEMORY_SIZE_RESPONSE`
+
+    Additional Fields:
+    - `domain` (`string`): The name of the memory domain to check
+
 - `GUARD`  
     Checks a section of memory against `expected_data`. If the bytes starting
     at `address` do not match `expected_data`, the response will have `value`
@@ -216,6 +224,12 @@ Response:
     Additional Fields:
     - `value` (`string`): The returned hash
 
+- `MEMORY_SIZE_RESPONSE`  
+    Contains the size in bytes of the specified memory domain.
+
+    Additional Fields:
+    - `value` (`number`): The size of the domain in bytes
+
 - `GUARD_RESPONSE`  
     The result of an attempted `GUARD` request.
 
@@ -376,6 +390,15 @@ request_handlers = {
         return res
     end,
 
+    ["MEMORY_SIZE"] = function (req)
+        local res = {}
+
+        res["type"] = "MEMORY_SIZE_RESPONSE"
+        res["value"] = memory.getmemorydomainsize(req["domain"])
+
+        return res
+    end,
+
     ["GUARD"] = function (req)
         local res = {}
         local expected_data = base64.decode(req["expected_data"])

worlds/_bizhawk/__init__.py

@@ -151,7 +151,7 @@ async def ping(ctx: BizHawkContext) -> None:
 
 
 async def get_hash(ctx: BizHawkContext) -> str:
-    """Gets the system name for the currently loaded ROM"""
+    """Gets the hash value of the currently loaded ROM"""
     res = (await send_requests(ctx, [{"type": "HASH"}]))[0]
 
     if res["type"] != "HASH_RESPONSE":
@@ -160,6 +160,16 @@ async def get_hash(ctx: BizHawkContext) -> str:
     return res["value"]
 
 
+async def get_memory_size(ctx: BizHawkContext, domain: str) -> int:
+    """Gets the size in bytes of the specified memory domain"""
+    res = (await send_requests(ctx, [{"type": "MEMORY_SIZE", "domain": domain}]))[0]
+
+    if res["type"] != "MEMORY_SIZE_RESPONSE":
+        raise SyncError(f"Expected response of type MEMORY_SIZE_RESPONSE but got {res['type']}")
+
+    return res["value"]
+
+
 async def get_system(ctx: BizHawkContext) -> str:
     """Gets the system name for the currently loaded ROM"""
     res = (await send_requests(ctx, [{"type": "SYSTEM"}]))[0]

worlds/mm2/client.py

@@ -214,10 +214,19 @@ class MegaMan2Client(BizHawkClient):
     last_wily: Optional[int] = None  # default to wily 1
 
     async def validate_rom(self, ctx: "BizHawkClientContext") -> bool:
-        from worlds._bizhawk import RequestFailedError, read
+        from worlds._bizhawk import RequestFailedError, read, get_memory_size
         from . import MM2World
 
         try:
+            if (await get_memory_size(ctx.bizhawk_ctx, "PRG ROM")) < 0x3FFB0:
+                if "pool" in ctx.command_processor.commands:
+                    ctx.command_processor.commands.pop("pool")
+                if "request" in ctx.command_processor.commands:
+                    ctx.command_processor.commands.pop("request")
+                if "autoheal" in ctx.command_processor.commands:
+                    ctx.command_processor.commands.pop("autoheal")
+                return False
+
             game_name, version = (await read(ctx.bizhawk_ctx, [(0x3FFB0, 21, "PRG ROM"),
                                                                (0x3FFC8, 3, "PRG ROM")]))
             if game_name[:3] != b"MM2" or version != bytes(MM2World.world_version):