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# 3bf01e6e95ae retro-remote-debug-controller / client / emu_control.py
3.9 KiB · Python · last changed HTTP control contract, portable server core, and shared client 3 months ago source blame history raw
961b3c61 Andy McCall 1 
"""emu_control.py — shared client for the Retro Remote Debug Controller.
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One client for every port's pytest suite. Speaks the HTTP contract in
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../SPEC.md (0.1.x). Depends only on the stdlib; Pillow is optional and only
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needed for .screenshot().
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    from emu_control import EmuControl
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    emu = EmuControl(port=8080)      # emulator started with -controlport 8080
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    emu.wait_ready()
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    emu.step(frames=120)
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    assert emu.regs()["a"] == 0
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    data = emu.mem(0x0400, 256, bank=1)
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    img = emu.screenshot()           # PIL.Image (requires Pillow)
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"""
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from __future__ import annotations
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import io
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import json
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import time
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import urllib.error
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import urllib.request
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CONTRACT_MAJOR = 0
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class EmuControlError(RuntimeError):
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    pass
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class EmuControl:
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    def __init__(self, port: int, host: str = "127.0.0.1", timeout: float = 5.0):
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        self.base = f"http://{host}:{port}"
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        self.timeout = timeout
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    # -- transport ---------------------------------------------------------
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    def _get(self, path: str) -> tuple[bytes, str]:
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        try:
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            with urllib.request.urlopen(self.base + path, timeout=self.timeout) as r:
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                return r.read(), r.headers.get_content_type()
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        except urllib.error.HTTPError as e:
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            raise EmuControlError(f"GET {path} -> {e.code}: {e.read()!r}") from e
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    def _post(self, path: str) -> bytes:
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        req = urllib.request.Request(self.base + path, method="POST", data=b"")
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        try:
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            with urllib.request.urlopen(req, timeout=self.timeout) as r:
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                return r.read()
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        except urllib.error.HTTPError as e:
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            raise EmuControlError(f"POST {path} -> {e.code}: {e.read()!r}") from e
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    # -- endpoints ---------------------------------------------------------
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    def status(self) -> dict:
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        body, _ = self._get("/status")
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        st = json.loads(body)
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        major = int(str(st.get("contract", "0")).split(".")[0])
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        if major != CONTRACT_MAJOR:
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            raise EmuControlError(
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                f"contract major mismatch: emulator {st.get('contract')} "
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                f"vs client {CONTRACT_MAJOR}.x"
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            )
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        return st
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    def frame(self) -> int:
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        return int(self.status()["frame"])
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    def regs(self) -> dict:
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        body, _ = self._get("/regs")
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        return json.loads(body)
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    def mem(self, addr: int, length: int, bank: int | None = None) -> bytes:
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        path = f"/mem?addr={addr}&len={length}"
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        if bank is not None:
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            path += f"&bank={bank}"
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        body, _ = self._get(path)
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        return body
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    def step(self, frames: int = 1) -> int:
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        body = self._post(f"/step?frames={frames}")
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        return int(json.loads(body)["frame"])
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    def pause(self) -> None:
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        self._post("/pause")
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    def resume(self) -> None:
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        self._post("/resume")
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    def screenshot(self):
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        """Return the live screen as a PIL.Image (requires Pillow)."""
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        body, ctype = self._get("/screenshot")
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        try:
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            from PIL import Image
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        except ImportError as e:  # pragma: no cover
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            raise EmuControlError("screenshot() needs Pillow (pip install pillow)") from e
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        return Image.open(io.BytesIO(body))
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    # -- helpers -----------------------------------------------------------
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    def wait_ready(self, tries: int = 100, delay: float = 0.05) -> dict:
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        """Poll /status until the server answers (emulator boot race)."""
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        last = None
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        for _ in range(tries):
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            try:
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                return self.status()
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            except (EmuControlError, urllib.error.URLError, ConnectionError) as e:
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                last = e
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                time.sleep(delay)
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        raise EmuControlError(f"emulator control port never came up: {last}")
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    def run_to_frame(self, target: int) -> int:
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        """Step until the frame counter reaches >= target."""
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        cur = self.frame()
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        if target > cur:
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            self.step(frames=target - cur)
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        return self.frame()