llama-stack-mirror/llama_stack/strong_typing/topological.py
Mustafa Elbehery 407c3e3bad feat: use XDG directory standards
Signed-off-by: Mustafa Elbehery <melbeher@redhat.com>
2025-07-22 23:29:23 +02:00

90 lines
2.7 KiB
Python

# Copyright (c) Meta Platforms, Inc. and affiliates.
# All rights reserved.
#
# This source code is licensed under the terms described in the LICENSE file in
# the root directory of this source tree.
"""
Type-safe data interchange for Python data classes.
:see: https://github.com/hunyadi/strong_typing
"""
from collections.abc import Callable, Iterable
from typing import TypeVar
from .inspection import TypeCollector
T = TypeVar("T")
def topological_sort(graph: dict[T, set[T]]) -> list[T]:
"""
Performs a topological sort of a graph.
Nodes with no outgoing edges are first. Nodes with no incoming edges are last.
The topological ordering is not unique.
:param graph: A dictionary of mappings from nodes to adjacent nodes. Keys and set members must be hashable.
:returns: The list of nodes in topological order.
"""
# empty list that will contain the sorted nodes (in reverse order)
ordered: list[T] = []
seen: dict[T, bool] = {}
def _visit(n: T) -> None:
status = seen.get(n)
if status is not None:
if status: # node has a permanent mark
return
else: # node has a temporary mark
raise RuntimeError(f"cycle detected in graph for node {n}")
seen[n] = False # apply temporary mark
for m in graph[n]: # visit all adjacent nodes
if m != n: # ignore self-referencing nodes
_visit(m)
seen[n] = True # apply permanent mark
ordered.append(n)
for n in graph.keys():
_visit(n)
return ordered
def type_topological_sort(
types: Iterable[type],
dependency_fn: Callable[[type], Iterable[type]] | None = None,
) -> list[type]:
"""
Performs a topological sort of a list of types.
Types that don't depend on other types (i.e. fundamental types) are first. Types on which no other types depend
are last. The topological ordering is not unique.
:param types: A list of types (simple or composite).
:param dependency_fn: Returns a list of additional dependencies for a class (e.g. classes referenced by a foreign key).
:returns: The list of types in topological order.
"""
if not all(isinstance(typ, type) for typ in types):
raise TypeError("expected a list of types")
collector = TypeCollector()
collector.traverse_all(types)
graph = collector.graph
if dependency_fn:
new_types: set[type] = set()
for source_type, references in graph.items():
dependent_types = dependency_fn(source_type)
references.update(dependent_types)
new_types.update(dependent_types)
for new_type in new_types:
graph[new_type] = set()
return topological_sort(graph)