1 files changed, 184 insertions, 0 deletions
diff --git a/src/debputy/maintscript_snippet.py b/src/debputy/maintscript_snippet.py
new file mode 100644
index 0000000..ca81ca5
--- /dev/null
+++ b/src/debputy/maintscript_snippet.py
@@ -0,0 +1,184 @@
+import dataclasses
+from typing import Sequence, Optional, List, Literal, Iterable, Dict, Self
+
+from debputy.manifest_parser.base_types import DebputyDispatchableType
+from debputy.manifest_parser.util import AttributePath
+
+STD_CONTROL_SCRIPTS = frozenset(
+    {
+        "preinst",
+        "prerm",
+        "postinst",
+        "postrm",
+    }
+)
+UDEB_CONTROL_SCRIPTS = frozenset(
+    {
+        "postinst",
+        "menutest",
+        "isinstallable",
+    }
+)
+ALL_CONTROL_SCRIPTS = STD_CONTROL_SCRIPTS | UDEB_CONTROL_SCRIPTS | {"config"}
+
+
+@dataclasses.dataclass(slots=True, frozen=True)
+class MaintscriptSnippet:
+    definition_source: str
+    snippet: str
+    snippet_order: Optional[Literal["service"]] = None
+
+    def script_content(self) -> str:
+        lines = [
+            f"# Snippet source: {self.definition_source}\n",
+            self.snippet,
+        ]
+        if not self.snippet.endswith("\n"):
+            lines.append("\n")
+        return "".join(lines)
+
+
+class MaintscriptSnippetContainer:
+    def __init__(self) -> None:
+        self._generic_snippets: List[MaintscriptSnippet] = []
+        self._snippets_by_order: Dict[Literal["service"], List[MaintscriptSnippet]] = {}
+
+    def copy(self) -> "MaintscriptSnippetContainer":
+        instance = self.__class__()
+        instance._generic_snippets = self._generic_snippets.copy()
+        instance._snippets_by_order = self._snippets_by_order.copy()
+        return instance
+
+    def append(self, maintscript_snippet: MaintscriptSnippet) -> None:
+        if maintscript_snippet.snippet_order is None:
+            self._generic_snippets.append(maintscript_snippet)
+        else:
+            if maintscript_snippet.snippet_order not in self._snippets_by_order:
+                self._snippets_by_order[maintscript_snippet.snippet_order] = []
+            self._snippets_by_order[maintscript_snippet.snippet_order].append(
+                maintscript_snippet
+            )
+
+    def has_content(self, snippet_order: Optional[Literal["service"]] = None) -> bool:
+        if snippet_order is None:
+            return bool(self._generic_snippets)
+        if snippet_order not in self._snippets_by_order:
+            return False
+        return bool(self._snippets_by_order[snippet_order])
+
+    def all_snippets(self) -> Iterable[MaintscriptSnippet]:
+        yield from self._generic_snippets
+        for snippets in self._snippets_by_order.values():
+            yield from snippets
+
+    def generate_snippet(
+        self,
+        tool_with_version: Optional[str] = None,
+        snippet_order: Optional[Literal["service"]] = None,
+        reverse: bool = False,
+    ) -> Optional[str]:
+        inner_content = ""
+        if snippet_order is None:
+            snippets = (
+                reversed(self._generic_snippets) if reverse else self._generic_snippets
+            )
+            inner_content = "".join(s.script_content() for s in snippets)
+        elif snippet_order in self._snippets_by_order:
+            snippets = self._snippets_by_order[snippet_order]
+            if reverse:
+                snippets = reversed(snippets)
+            inner_content = "".join(s.script_content() for s in snippets)
+
+        if not inner_content:
+            return None
+
+        if tool_with_version:
+            return (
+                f"# Automatically added by {tool_with_version}\n"
+                + inner_content
+                + "# End automatically added section"
+            )
+        return inner_content
+
+
+class DpkgMaintscriptHelperCommand(DebputyDispatchableType):
+    __slots__ = ("cmdline", "definition_source")
+
+    def __init__(self, cmdline: Sequence[str], definition_source: str):
+        self.cmdline = cmdline
+        self.definition_source = definition_source
+
+    @classmethod
+    def _finish_cmd(
+        cls,
+        definition_source: str,
+        cmdline: List[str],
+        prior_version: Optional[str],
+        owning_package: Optional[str],
+    ) -> Self:
+        if prior_version is not None:
+            cmdline.append(prior_version)
+        if owning_package is not None:
+            if prior_version is None:
+                # Empty is allowed according to `man dpkg-maintscript-helper`
+                cmdline.append("")
+            cmdline.append(owning_package)
+        return cls(
+            tuple(cmdline),
+            definition_source,
+        )
+
+    @classmethod
+    def rm_conffile(
+        cls,
+        definition_source: AttributePath,
+        conffile: str,
+        prior_version: Optional[str] = None,
+        owning_package: Optional[str] = None,
+    ) -> Self:
+        cmdline = ["rm_conffile", conffile]
+        return cls._finish_cmd(
+            definition_source.path, cmdline, prior_version, owning_package
+        )
+
+    @classmethod
+    def mv_conffile(
+        cls,
+        definition_source: AttributePath,
+        old_conffile: str,
+        new_confile: str,
+        prior_version: Optional[str] = None,
+        owning_package: Optional[str] = None,
+    ) -> Self:
+        cmdline = ["mv_conffile", old_conffile, new_confile]
+        return cls._finish_cmd(
+            definition_source.path, cmdline, prior_version, owning_package
+        )
+
+    @classmethod
+    def symlink_to_dir(
+        cls,
+        definition_source: AttributePath,
+        pathname: str,
+        old_target: str,
+        prior_version: Optional[str] = None,
+        owning_package: Optional[str] = None,
+    ) -> Self:
+        cmdline = ["symlink_to_dir", pathname, old_target]
+        return cls._finish_cmd(
+            definition_source.path, cmdline, prior_version, owning_package
+        )
+
+    @classmethod
+    def dir_to_symlink(
+        cls,
+        definition_source: AttributePath,
+        pathname: str,
+        new_target: str,
+        prior_version: Optional[str] = None,
+        owning_package: Optional[str] = None,
+    ) -> Self:
+        cmdline = ["dir_to_symlink", pathname, new_target]
+        return cls._finish_cmd(
+            definition_source.path, cmdline, prior_version, owning_package
+        )