72 lines
2.3 KiB
Python
72 lines
2.3 KiB
Python
# Copyright 2023-2024 SGLang Team
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# Licensed under the Apache License, Version 2.0 (the "License");
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# you may not use this file except in compliance with the License.
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# You may obtain a copy of the License at
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#
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# http://www.apache.org/licenses/LICENSE-2.0
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#
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# Unless required by applicable law or agreed to in writing, software
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# distributed under the License is distributed on an "AS IS" BASIS,
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# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
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# See the License for the specific language governing permissions and
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# limitations under the License.
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# ==============================================================================
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"""The baseclass of a backend for grammar-guided constrained decoding."""
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from concurrent.futures import Future, ThreadPoolExecutor
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from dataclasses import dataclass
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from threading import Event, Lock
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from typing import Any, Optional, Tuple
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@dataclass
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class CacheEntry:
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value: Any
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event: Event
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class BaseGrammarObject:
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pass
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class BaseGrammarBackend:
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def __init__(self):
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self.executor = ThreadPoolExecutor()
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self.cache = {}
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self.cache_lock = Lock()
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def init_value(self, key: Tuple[str, str]) -> BaseGrammarObject:
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with self.cache_lock:
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if key in self.cache:
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cache_hit = True
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entry = self.cache[key]
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else:
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cache_hit = False
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entry = CacheEntry(None, Event())
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self.cache[key] = entry
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if cache_hit:
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entry.event.wait()
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else:
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entry.value = self.init_value_impl(key)
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entry.event.set()
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return entry.value.copy() if entry.value else None
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def init_value_impl(self, key: Tuple[str, str]) -> BaseGrammarObject:
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raise NotImplementedError()
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def get_cached_value(self, key: Tuple[str, str]) -> Optional[BaseGrammarObject]:
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with self.cache_lock:
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entry = self.cache.get(key)
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if not entry or not entry.event.is_set():
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return None
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val = self.cache[key].value
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return val.copy() if val else None
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def get_future_value(self, key: Tuple[str, str]) -> Future:
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return self.executor.submit(self.init_value, key)
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def reset(self):
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with self.cache_lock:
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self.cache.clear()
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