OXYGENHUB
# 8ac19619e24b retro-remote-debug-controller / client / emu_control.py
5.0 KiB · Python · last changed Add conformance suite; client: raw PPM screenshot + PPM parser 3 months ago source blame history raw
1 
"""emu_control.py — shared client for the Retro Remote Debug Controller.
2
3 
One client for every port's pytest suite. Speaks the HTTP contract in
4 
../SPEC.md (0.1.x). Depends only on the stdlib; Pillow is optional and only
5 
needed for .screenshot().
6
7 
    from emu_control import EmuControl
8
9 
    emu = EmuControl(port=8080)      # emulator started with -controlport 8080
10 
    emu.wait_ready()
11 
    emu.step(frames=120)
12 
    assert emu.regs()["a"] == 0
13 
    data = emu.mem(0x0400, 256, bank=1)
14 
    img = emu.screenshot()           # PIL.Image (requires Pillow)
15 
"""
16
17 
from __future__ import annotations
18
19 
import io
20 
import json
21 
import time
22 
import urllib.error
23 
import urllib.request
24
25 
CONTRACT_MAJOR = 0
26
27
28 
class EmuControlError(RuntimeError):
29 
    pass
30
31
32 
def parse_ppm_header(data: bytes):
33 
    """Parse a binary PPM (P6) header. Returns (width, height, maxval, offset)
34 
    where offset is the index of the first pixel byte. Raises on malformed
35 
    input. Stdlib-only — no Pillow needed."""
36 
    if data[:2] != b"P6":
37 
        raise EmuControlError(f"not a P6 PPM (magic {data[:2]!r})")
38 
    fields, i, n = [], 2, len(data)
39 
    while len(fields) < 3 and i < n:
40 
        while i < n and data[i:i + 1].isspace():
41 
            i += 1
42 
        if i < n and data[i:i + 1] == b"#":            # comment to end of line
43 
            while i < n and data[i:i + 1] not in (b"\n", b"\r"):
44 
                i += 1
45 
            continue
46 
        start = i
47 
        while i < n and not data[i:i + 1].isspace():
48 
            i += 1
49 
        fields.append(int(data[start:i]))
50 
    if len(fields) < 3:
51 
        raise EmuControlError("truncated PPM header")
52 
    return fields[0], fields[1], fields[2], i + 1        # +1: single whitespace
53
54
55 
class EmuControl:
56 
    def __init__(self, port: int, host: str = "127.0.0.1", timeout: float = 5.0):
57 
        self.base = f"http://{host}:{port}"
58 
        self.timeout = timeout
59
60 
    # -- transport ---------------------------------------------------------
61 
    def _get(self, path: str) -> tuple[bytes, str]:
62 
        try:
63 
            with urllib.request.urlopen(self.base + path, timeout=self.timeout) as r:
64 
                return r.read(), r.headers.get_content_type()
65 
        except urllib.error.HTTPError as e:
66 
            raise EmuControlError(f"GET {path} -> {e.code}: {e.read()!r}") from e
67
68 
    def _post(self, path: str) -> bytes:
69 
        req = urllib.request.Request(self.base + path, method="POST", data=b"")
70 
        try:
71 
            with urllib.request.urlopen(req, timeout=self.timeout) as r:
72 
                return r.read()
73 
        except urllib.error.HTTPError as e:
74 
            raise EmuControlError(f"POST {path} -> {e.code}: {e.read()!r}") from e
75
76 
    # -- endpoints ---------------------------------------------------------
77 
    def status(self) -> dict:
78 
        body, _ = self._get("/status")
79 
        st = json.loads(body)
80 
        major = int(str(st.get("contract", "0")).split(".")[0])
81 
        if major != CONTRACT_MAJOR:
82 
            raise EmuControlError(
83 
                f"contract major mismatch: emulator {st.get('contract')} "
84 
                f"vs client {CONTRACT_MAJOR}.x"
85 
            )
86 
        return st
87
88 
    def frame(self) -> int:
89 
        return int(self.status()["frame"])
90
91 
    def regs(self) -> dict:
92 
        body, _ = self._get("/regs")
93 
        return json.loads(body)
94
95 
    def mem(self, addr: int, length: int, bank: int | None = None) -> bytes:
96 
        path = f"/mem?addr={addr}&len={length}"
97 
        if bank is not None:
98 
            path += f"&bank={bank}"
99 
        body, _ = self._get(path)
100 
        return body
101
102 
    def step(self, frames: int = 1) -> int:
103 
        body = self._post(f"/step?frames={frames}")
104 
        return int(json.loads(body)["frame"])
105
106 
    def pause(self) -> None:
107 
        self._post("/pause")
108
109 
    def resume(self) -> None:
110 
        self._post("/resume")
111
112 
    def screenshot_ppm(self) -> bytes:
113 
        """Return the live screen as raw PPM (P6) bytes. Stdlib-only."""
114 
        body, _ = self._get("/screenshot")
115 
        return body
116
117 
    def screenshot(self):
118 
        """Return the live screen as a PIL.Image (requires Pillow)."""
119 
        body = self.screenshot_ppm()
120 
        try:
121 
            from PIL import Image
122 
        except ImportError as e:  # pragma: no cover
123 
            raise EmuControlError("screenshot() needs Pillow (pip install pillow)") from e
124 
        return Image.open(io.BytesIO(body))
125
126 
    # -- helpers -----------------------------------------------------------
127 
    def wait_ready(self, tries: int = 100, delay: float = 0.05) -> dict:
128 
        """Poll /status until the server answers (emulator boot race)."""
129 
        last = None
130 
        for _ in range(tries):
131 
            try:
132 
                return self.status()
133 
            except (EmuControlError, urllib.error.URLError, ConnectionError) as e:
134 
                last = e
135 
                time.sleep(delay)
136 
        raise EmuControlError(f"emulator control port never came up: {last}")
137
138 
    def run_to_frame(self, target: int) -> int:
139 
        """Step until the frame counter reaches >= target."""
140 
        cur = self.frame()
141 
        if target > cur:
142 
            self.step(frames=target - cur)
143 
        return self.frame()