Update iso-prototype.py

src/iso-prototype.py

@@ -379,14 +379,114 @@ def find_existing_record(iso, logical: PurePosixPath) -> dict[str, str]:
     return found
 
 
-def namespace_kwargs(iso, logical: PurePosixPath, *, is_dir: bool = False) -> dict[str, str]:
-    kwargs: dict[str, str] = {"iso_path": iso_candidates(logical, is_dir=is_dir)[0]}
+def iso9660_alias_component(
+    name: str,
+    *,
+    is_dir: bool,
+    interchange_level: int,
+) -> str:
+    value = name.upper()
+
+    # ISO9660 level 4 permits arbitrary characters. For levels 1-3, replace
+    # characters outside the d1 set accepted by PyCdlib. A file's dot remains
+    # the separator between its name and extension.
+    if interchange_level < 4:
+        allowed = set("ABCDEFGHIJKLMNOPQRSTUVWXYZ0123456789_")
+
+        def sanitize(part: str) -> str:
+            return "".join(
+                char if char in allowed else "_"
+                for char in part
+            )
+
+        if is_dir:
+            value = sanitize(value)
+        else:
+            stem, dot, extension = value.rpartition(".")
+
+            if not dot:
+                stem = value
+                extension = ""
+
+            value = sanitize(stem)
+
+            if extension:
+                value += "." + sanitize(extension)
+
+    if not value:
+        value = "_"
+
+    if interchange_level == 1:
+        if is_dir:
+            return value[:8]
+
+        stem, dot, extension = value.partition(".")
+        stem = stem[:8]
+
+        if dot:
+            return f"{stem}.{extension[:3]}"
+
+        return stem
+
+    return value
+
+
+def iso9660_alias_path(
+    iso,
+    logical: PurePosixPath,
+    *,
+    is_dir: bool = False,
+) -> str:
+    logical_parts = [
+        part
+        for part in logical.parts
+        if part != "/"
+    ]
+
+    aliases: list[str] = []
+
+    for index, part in enumerate(logical_parts):
+        component_is_dir = (
+            is_dir or index < len(logical_parts) - 1
+        )
+
+        aliases.append(
+            iso9660_alias_component(
+                part,
+                is_dir=component_is_dir,
+                interchange_level=iso.interchange_level,
+            )
+        )
+
+    path = "/" + "/".join(aliases)
+
+    if is_dir:
+        return path
+
+    return path + ";1"
+
+
+def namespace_kwargs(
+    iso,
+    logical: PurePosixPath,
+    *,
+    is_dir: bool = False,
+) -> dict[str, str]:
+    kwargs: dict[str, str] = {
+        "iso_path": iso9660_alias_path(
+            iso,
+            logical,
+            is_dir=is_dir,
+        )
+    }
+
     if iso.has_joliet():
         kwargs["joliet_path"] = str(logical)
+
     if iso.has_udf():
         kwargs["udf_path"] = str(logical)
-    return kwargs
 
+    return kwargs
 
 def ensure_parent_directories(iso, logical: PurePosixPath) -> None:
     current = PurePosixPath("/")