# SPDX-License-Identifier: Apache-2.0
# SPDX-FileCopyrightText: Copyright contributors to the vLLM project
"""Base class for attention-like layers."""
from abc import ABC, abstractmethod
from typing import TYPE_CHECKING

if TYPE_CHECKING:
    from vllm.attention.backends.abstract import AttentionBackend


class AttentionLayerBase(ABC):
    """
    Base class for attention-like layers (Attention, Mamba, etc.) 
    that support the v1 engine.
    
    This provides a common interface for getting attention backends 
    from different layer types.
    """

    @abstractmethod
    def get_attn_backend(self) -> type["AttentionBackend"]:
        """Get the attention backend class for this layer."""
        pass