117 lines
3.3 KiB
Python
117 lines
3.3 KiB
Python
"""Preview generation worker subprocess.
|
|
|
|
Two modes are supported:
|
|
1) Legacy one-shot mode: argv has path/quality/maxsize/maxzoom.
|
|
2) Long-lived mode: read JSONL commands from stdin and write framed responses.
|
|
|
|
Framed response format:
|
|
(blake3(packet))(uint32 json size)(uint32 payload size)(json)(binary payload)
|
|
where packet = (uint32 json size)(uint32 payload size)(json)(binary payload).
|
|
"""
|
|
|
|
import logging
|
|
import contextlib
|
|
import io
|
|
import struct
|
|
import sys
|
|
from pathlib import Path
|
|
|
|
import msgspec
|
|
from blake3 import blake3
|
|
|
|
|
|
class PreviewRequest(msgspec.Struct, omit_defaults=True):
|
|
path: str
|
|
quality: int
|
|
maxsize: int
|
|
maxzoom: float
|
|
|
|
|
|
class PreviewResponse(msgspec.Struct, omit_defaults=True):
|
|
ok: bool
|
|
mime: str | None = None
|
|
backend: str | None = None
|
|
timings: list[float] | None = None
|
|
error: str | None = None
|
|
stderr: str | None = None
|
|
|
|
|
|
_enc = msgspec.json.Encoder()
|
|
_dec_req = msgspec.json.Decoder(PreviewRequest)
|
|
|
|
|
|
def _write_response(resp: PreviewResponse, payload: bytes) -> None:
|
|
meta_bytes = _enc.encode(resp)
|
|
packet = struct.pack("<II", len(meta_bytes), len(payload)) + meta_bytes + payload
|
|
checksum = blake3(packet).digest()
|
|
sys.stdout.buffer.write(checksum)
|
|
sys.stdout.buffer.write(packet)
|
|
sys.stdout.buffer.flush()
|
|
|
|
|
|
def _run_once() -> None:
|
|
if len(sys.argv) != 5:
|
|
sys.stderr.write(f"Usage: {sys.argv[0]} <path> <quality> <maxsize> <maxzoom>\n")
|
|
sys.exit(1)
|
|
|
|
from cista.preview import dispatch
|
|
|
|
path = Path(sys.argv[1])
|
|
quality = int(sys.argv[2])
|
|
maxsize = int(sys.argv[3])
|
|
maxzoom = float(sys.argv[4])
|
|
result, _ = dispatch(path, quality, maxsize, maxzoom)
|
|
if result:
|
|
sys.stdout.buffer.write(result)
|
|
sys.stdout.buffer.flush()
|
|
|
|
|
|
def _run_loop() -> None:
|
|
from cista.preview import dispatch
|
|
|
|
while True:
|
|
line = sys.stdin.buffer.readline()
|
|
if not line:
|
|
return
|
|
stderr_capture = io.StringIO()
|
|
handler = logging.StreamHandler(stderr_capture)
|
|
root_logger = logging.getLogger()
|
|
root_logger.addHandler(handler)
|
|
try:
|
|
with contextlib.redirect_stderr(stderr_capture):
|
|
req = _dec_req.decode(line)
|
|
result, resp = dispatch(
|
|
Path(req.path), req.quality, req.maxsize, req.maxzoom
|
|
)
|
|
if not resp.ok:
|
|
captured = stderr_capture.getvalue().strip()
|
|
if captured:
|
|
resp = PreviewResponse(
|
|
ok=False,
|
|
backend=resp.backend,
|
|
error=resp.error,
|
|
stderr=captured,
|
|
)
|
|
_write_response(resp, result or b"")
|
|
except Exception as e:
|
|
captured = stderr_capture.getvalue().strip()
|
|
_write_response(
|
|
PreviewResponse(ok=False, error=str(e), stderr=captured or None), b""
|
|
)
|
|
finally:
|
|
root_logger.removeHandler(handler)
|
|
handler.close()
|
|
|
|
|
|
def main() -> None:
|
|
# Configure all log output to stderr before any imports that may emit logs.
|
|
logging.basicConfig(stream=sys.stderr, level=logging.INFO)
|
|
if len(sys.argv) > 1:
|
|
_run_once()
|
|
return
|
|
_run_loop()
|
|
|
|
|
|
if __name__ == "__main__":
|
|
main()
|