add # 新增使用开源字体

src/farm_render/font_bundle.py

@@ -0,0 +1,106 @@
+"""从 service 仓库下载原版小赖字体，校验后原子写入本地缓存。"""
+
+import hashlib
+from importlib import resources
+import json
+from pathlib import Path
+import tempfile
+from zipfile import ZipFile
+
+from .bundle import _LOCK, _copy_remote, validate_options
+
+
+FONT_NAME = "Xiaolai-Regular.ttf"
+FILES = {
+    FONT_NAME: (
+        22220806,
+        "e2f68daf0e72777a8cf58bc83de1b98634b251e537ddbfca24b0ae50d1802da2",
+    ),
+    "OFL-Xiaolai.txt": (
+        4432,
+        "0df7e09be4c2c850a48bd8beb9cd64b343aad49cd5d3f6cfb2ad2e3d28a56ca4",
+    ),
+}
+
+
+def expected_manifest():
+    return json.loads(resources.files(__package__).joinpath(
+        "data", "font-manifest.json",
+    ).read_bytes())
+
+
+def _valid(path, size, digest):
+    if not path.is_file() or path.stat().st_size != size:
+        return False
+    checksum = hashlib.sha256()
+    with path.open("rb") as stream:
+        for chunk in iter(lambda: stream.read(65536), b""):
+            checksum.update(chunk)
+    return checksum.hexdigest() == digest
+
+
+def _atomic_write(path, content):
+    temporary = None
+    try:
+        with tempfile.NamedTemporaryFile(
+            dir=path.parent, suffix=".download", delete=False,
+        ) as stream:
+            temporary = Path(stream.name)
+            stream.write(content)
+        temporary.replace(path)
+    finally:
+        if temporary is not None:
+            temporary.unlink(missing_ok=True)
+
+
+def ensure_font(data_dir, source="Github", service_url=""):
+    """校验全部缓存文件；无效时下载，始终同时保留完整 OFL 许可。"""
+    validate_options(source, service_url)
+    manifest = expected_manifest()
+    root = Path(data_dir) / "fonts" / manifest["sha256"]
+    with _LOCK:
+        if all(_valid(root / name, *checks)
+               for name, checks in FILES.items()):
+            return root / FONT_NAME
+        root.mkdir(parents=True, exist_ok=True)
+        archive_path = root / "assets.zip"
+        if not _valid(archive_path, manifest["size_bytes"],
+                      manifest["sha256"]):
+            url = (
+                service_url.rstrip("/") + "/v1/fonts/"
+                + manifest["sha256"] + "/assets.zip"
+                if source == "farm_service"
+                else manifest["sources"][source.lower()]
+            )
+            temporary = None
+            try:
+                with tempfile.NamedTemporaryFile(
+                    dir=root, suffix=".download", delete=False,
+                ) as stream:
+                    temporary = Path(stream.name)
+                    _copy_remote(url, stream, manifest["size_bytes"])
+                if not _valid(temporary, manifest["size_bytes"],
+                              manifest["sha256"]):
+                    raise ValueError("Font archive size or SHA256 mismatch")
+                temporary.replace(archive_path)
+            finally:
+                if temporary is not None:
+                    temporary.unlink(missing_ok=True)
+        with ZipFile(archive_path) as archive:
+            entries = archive.infolist()
+            if (len(entries) != len(FILES)
+                    or {item.filename for item in entries} != set(FILES)):
+                raise ValueError("Unexpected font archive contents")
+            content = {}
+            for item in entries:
+                size, digest = FILES[item.filename]
+                if item.file_size != size or item.flag_bits & 1:
+                    raise ValueError("Invalid font archive member")
+                value = archive.read(item)
+                if hashlib.sha256(value).hexdigest() != digest:
+                    raise ValueError("Font member SHA256 mismatch")
+                content[item.filename] = value
+        # 先写许可，再使字体可用；不使用 extractall 或远端提供的路径。
+        for name in ("OFL-Xiaolai.txt", FONT_NAME):
+            _atomic_write(root / name, content[name])
+        return root / FONT_NAME