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from typing import List
from queue import Queue
import torch
def build_chat_input(model, tokenizer, messages: List[dict], max_new_tokens: int=0):
def _parse_messages(messages, split_role="user"):
system, rounds = "", []
round = []
for i, message in enumerate(messages):
if message["role"] == "system":
assert i == 0
system = message["content"]
continue
if message["role"] == split_role and round:
rounds.append(round)
round = []
round.append(message)
if round:
rounds.append(round)
return system, rounds
max_new_tokens = max_new_tokens or model.generation_config.max_new_tokens
max_input_tokens = model.config.model_max_length - max_new_tokens
system, rounds = _parse_messages(messages, split_role="user")
system_tokens = tokenizer.encode(system)
max_history_tokens = max_input_tokens - len(system_tokens)
history_tokens = []
for round in rounds[::-1]:
round_tokens = []
for message in round:
if message["role"] == "user":
round_tokens.append(model.generation_config.user_token_id)
else:
round_tokens.append(model.generation_config.assistant_token_id)
round_tokens.extend(tokenizer.encode(message["content"]))
if len(history_tokens) == 0 or len(history_tokens) + len(round_tokens) <= max_history_tokens:
history_tokens = round_tokens + history_tokens # concat left
if len(history_tokens) < max_history_tokens:
continue
break
input_tokens = system_tokens + history_tokens
if messages[-1]["role"] != "assistant":
input_tokens.append(model.generation_config.assistant_token_id)
input_tokens = input_tokens[-max_input_tokens:] # truncate left
return torch.LongTensor([input_tokens]).to(model.device)
class TextIterStreamer:
def __init__(self, tokenizer, skip_prompt=False, skip_special_tokens=False):
self.tokenizer = tokenizer
self.skip_prompt = skip_prompt
self.skip_special_tokens = skip_special_tokens
self.tokens = []
self.text_queue = Queue()
self.next_tokens_are_prompt = True
def put(self, value):
if self.skip_prompt and self.next_tokens_are_prompt:
self.next_tokens_are_prompt = False
else:
if len(value.shape) > 1:
value = value[0]
self.tokens.extend(value.tolist())
self.text_queue.put(
self.tokenizer.decode(self.tokens, skip_special_tokens=self.skip_special_tokens))
def end(self):
self.text_queue.put(None)
def __iter__(self):
return self
def __next__(self):
value = self.text_queue.get()
if value is None:
raise StopIteration()
else:
return value
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