initial work on procedure patch

Patch.py

@@ -2,13 +2,13 @@ from __future__ import annotations
 
 import os
 import sys
-from typing import Tuple, Optional, TypedDict
+from typing import Tuple, Optional, TypedDict, Union
 
 if __name__ == "__main__":
     import ModuleUpdate
     ModuleUpdate.update()
 
-from worlds.Files import AutoPatchRegister, APDeltaPatch
+from worlds.Files import AutoPatchRegister, APDeltaPatch, APProcedurePatch
 
 
 class RomMeta(TypedDict):
@@ -20,7 +20,7 @@ class RomMeta(TypedDict):
 def create_rom_file(patch_file: str) -> Tuple[RomMeta, str]:
     auto_handler = AutoPatchRegister.get_handler(patch_file)
     if auto_handler:
-        handler: APDeltaPatch = auto_handler(patch_file)
+        handler: Union[APDeltaPatch, APProcedurePatch] = auto_handler(patch_file)
         target = os.path.splitext(patch_file)[0]+handler.result_file_ending
         handler.patch(target)
         return {"server": handler.server,

worlds/Files.py

@@ -1,9 +1,10 @@
 from __future__ import annotations
 
 import json
+import struct
 import zipfile
 
-from typing import ClassVar, Dict, Tuple, Any, Optional, Union, BinaryIO
+from typing import ClassVar, Dict, Tuple, Any, Optional, Union, BinaryIO, List
 
 import bsdiff4
 
@@ -33,6 +34,24 @@ class AutoPatchRegister(type):
 current_patch_version: int = 5
 
 
+class AutoPatchExtensionRegister(type):
+    patch_types: ClassVar[Dict[str, AutoPatchExtensionRegister]] = {}
+
+    def __new__(mcs, name: str, bases: Tuple[type, ...], dct: Dict[str, Any]) -> AutoPatchExtensionRegister:
+        # construct class
+        new_class = super().__new__(mcs, name, bases, dct)
+        if "game" in dct:
+            AutoPatchExtensionRegister.patch_types[dct["game"]] = new_class
+        return new_class
+
+    @staticmethod
+    def get_handler(game: str) -> Optional[AutoPatchExtensionRegister]:
+        for patch_type, handler in AutoPatchExtensionRegister.patch_types.items():
+            if patch_type == game:
+                return handler
+        return None
+
+
 class APContainer:
     """A zipfile containing at least archipelago.json"""
     version: int = current_patch_version
@@ -154,3 +173,102 @@ class APDeltaPatch(APContainer, metaclass=AutoPatchRegister):
         result = bsdiff4.patch(self.get_source_data_with_cache(), self.delta)
         with open(target, "wb") as f:
             f.write(result)
+
+
+class APProcedurePatch(APContainer, metaclass=AutoPatchRegister):
+    """
+    An APContainer that defines a procedure to produce the desired file.
+    """
+    procedure: List[str]
+    tokens: List[Tuple[int, bytes]]
+    hash: Optional[str]  # base checksum of source file
+    source_data: bytes
+    patch_file_ending: str = ""
+    result_file_ending: str = ".sfc"
+    token_data: Optional[bytes] = None
+
+
+    @classmethod
+    def get_source_data(cls) -> bytes:
+        """Get Base data"""
+        raise NotImplementedError()
+
+    @classmethod
+    def get_source_data_with_cache(cls) -> bytes:
+        if not hasattr(cls, "source_data"):
+            cls.source_data = cls.get_source_data()
+        return cls.source_data
+
+    def __init__(self, *args: Any, **kwargs: Any):
+        self.tokens = list()
+        super(APProcedurePatch, self).__init__(*args, **kwargs)
+
+    def get_manifest(self) -> Dict[str, Any]:
+        manifest = super(APProcedurePatch, self).get_manifest()
+        manifest["base_checksum"] = self.hash
+        manifest["result_file_ending"] = self.result_file_ending
+        manifest["patch_file_ending"] = self.patch_file_ending
+        return manifest
+
+    def read_tokens(self) -> None:
+        if not self.token_data:
+            self.read()
+        token_count = struct.unpack("I", self.token_data[0:4])[0]
+        bpr = 4
+        for _ in range(token_count):
+            offset = struct.unpack("I", self.token_data[bpr:bpr+4])[0]
+            size = struct.unpack("I", self.token_data[bpr+4:bpr+8])[0]
+            data = self.token_data[bpr+8:bpr+8+size]
+            self.tokens.append((offset, data))
+            bpr += 8 + size
+
+    def write_token(self, offset: int, data: bytes) -> None:
+        self.tokens.append((offset,data))  # lazy write these when we go to generate the patch
+
+    def get_token_binary(self) -> bytes:
+        data = bytearray()
+        data.extend(struct.pack("I", len(self.tokens)))
+        for offset, bin_data in self.tokens:
+            data.extend(struct.pack("I", offset))
+            data.extend(struct.pack("I", len(bin_data)))
+            data.extend(bin_data)
+        return data
+
+    def process_token_binary(self, data: bytes) -> bytes:
+        self.read_tokens()
+        data = bytearray(data)
+        for offset, token_data in self.tokens:
+            data[offset:offset+len(token_data)] = token_data
+        return data
+
+    def read_contents(self, opened_zipfile: zipfile.ZipFile) -> None:
+        super(APProcedurePatch, self).read_contents(opened_zipfile)
+        if "token_data.bin" in opened_zipfile.namelist():
+            self.token_data = opened_zipfile.read("token_data.bin")
+
+    def write_contents(self, opened_zipfile: zipfile.ZipFile) -> None:
+        super(APProcedurePatch, self).write_contents(opened_zipfile)
+        if len(self.tokens) > 0:
+            opened_zipfile.writestr("token_data.bin", self.get_token_binary())
+
+    def patch(self, target: str):
+        base_data = self.get_source_data_with_cache()
+        patch_extender = AutoPatchExtensionRegister.get_handler(self.game)
+        for step in self.procedure:
+            if step == "apply_tokens":
+                base_data = self.process_token_binary(base_data)
+            elif patch_extender is not None:
+                extension = getattr(patch_extender, step, None)
+                if extension is not None:
+                    base_data = extension(base_data)
+                else:
+                    raise NotImplementedError(f"Unknown procedure {step} for {self.game}.")
+            else:
+                raise NotImplementedError(f"Unknown procedure {step} for {self.game}.")
+        with open(target, 'wb') as f:
+            f.write(base_data)
+
+
+class APPatchExtension(metaclass=AutoPatchExtensionRegister):
+    game: str
+