[Refactor] refactor spec decode

Signed-off-by: wangxiyuan <[email protected]>

Author: wangxiyuan

vllm_ascend/models/qwen2_vl.py

@@ -349,4 +349,4 @@ def __init__(self, *, vllm_config: VllmConfig, prefix: str = ""):
             quant_config=self._maybe_ignore_quant_config(
                 vllm_config.quant_config),
             prefix=maybe_prefix(prefix, "visual"),
-        )
+        )

vllm_ascend/spec_decode/__init__.py

@@ -0,0 +1,33 @@
+#
+# Copyright (c) 2025 Huawei Technologies Co., Ltd. All Rights Reserved.
+# Copyright 2023 The vLLM team.
+#
+# Licensed under the Apache License, Version 2.0 (the "License");
+# you may not use this file except in compliance with the License.
+# You may obtain a copy of the License at
+#
+#     http://www.apache.org/licenses/LICENSE-2.0
+#
+# Unless required by applicable law or agreed to in writing, software
+# distributed under the License is distributed on an "AS IS" BASIS,
+# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+# See the License for the specific language governing permissions and
+# limitations under the License.
+# This file is a part of the vllm-ascend project.
+# Adapted from vllm-project/vllm/vllm/worker/gpu_model_runner.py
+#
+from vllm_ascend.spec_decode.eagle_proposer import EagleProposer
+from vllm_ascend.spec_decode.mtp_proposer import MtpProposer
+from vllm_ascend.spec_decode.ngram_proposer import NgramProposer
+
+
+def get_spec_decode_method(method, vllm_config, device, runner):
+    if method == "ngram":
+        return NgramProposer(vllm_config, device, runner)
+    elif method in ["eagle", "eagle3"]:
+        return EagleProposer(vllm_config, device, runner)
+    elif method == 'deepseek_mtp':
+        return MtpProposer(vllm_config, device, runner)
+    else:
+        raise ValueError("Unknown speculative decoding method: "
+                         f"{method}")