327 lines
12 KiB
Python
327 lines
12 KiB
Python
import json
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import sys
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from collections import namedtuple
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from itertools import chain
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from typing import Dict, Generator, List, Optional, Tuple
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import requests
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from deltas import Equal, Insert, Delete, DiffEngine, Operation, RegexTokenizer, tokenizers
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TOKENIZER = tokenizers.wikitext_split
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def find_greatest_le_key(target_key, data_dict):
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for key in data_dict: # Iterates over keys in insertion order (which is sorted)
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if key <= target_key:
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found_key = (
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key # This is the largest key found so far that satisfies the condition
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)
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else:
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# Since the dictionary is sorted, if key > target_key,
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# all subsequent keys will also be > target_key.
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return found_key or key
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def compute_diffs(url: str, texts: list[str]) -> list:
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response = None
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try:
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response = requests.post(url, json=texts)
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response.raise_for_status()
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incremental_diffs = response.json()
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except requests.exceptions.ConnectionError as e:
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print(
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f"Connection Error: Could not connect to the server at {url}. Make sure your local server is running."
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)
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print(e)
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raise e
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except requests.exceptions.HTTPError as e:
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print(f"HTTP Error: {e}")
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if response is not None:
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print(f"Response Body: {response.text}")
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raise e
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except requests.exceptions.JSONDecodeError as e:
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# Must come before RequestException as JSONDecodeError is
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# a subclass.
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print(f"JSON Decode Error: {e}", file=sys.stderr)
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if response is not None:
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print(f"Response Body: {response.text}", file=sys.stderr)
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raise e
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except requests.exceptions.RequestException as e:
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print(f"An unexpected error occurred: {e}")
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raise e
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return incremental_diffs
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class DiffToOperationMap:
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def __init__(self, diff, tokenizer):
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self.tokenizer = tokenizer
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self.diff = json.loads(diff)
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# the code below is designed to work in bytes because that's how wikidiff2 indexes
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self.from_last_end_bytes = 0
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self.from_last_to_bytes = 0
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self.n_from_start_tokens = 0
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self.n_to_start_tokens = 0
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self.last_to_start_line = 0
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self.last_from_start_line = 0
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self.from_last_end_bytes = 0
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self.to_last_end_bytes = 0
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# keeps track of the number of tokens seen so far
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# to avoid repeated tokenization
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self.from_byte_token_index_map: Dict[int, int] = {}
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self.to_byte_token_index_map: Dict[int, int] = {}
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self.par_move_dict = {}
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def tokenize(self, bytes):
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return self.tokenizer.tokenize(bytes.decode("utf-8"))
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def to_operations(self):
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parmoves = []
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for entry in self.diff["diff"]:
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offset = entry["offset"]
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text = entry["text"]
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# ignore empty diffs. They don't have any tokens
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if len(text) == 0:
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continue
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# this is the first byte of the line in the 'from' revision.
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from_start_line = entry["offset"]["from"]
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# this is the first byte of the line in the 'to' revision.
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to_start_line = entry["offset"]["to"]
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if entry["type"] == 0:
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yield from self.doEqual(text, offset)
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# a line included in the 'to' revision, but not in the 'from' revision
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elif entry["type"] == 1:
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yield from self.doInsert(text, offset)
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# a line included in the 'from' revision, but not in the 'to' revision
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elif entry["type"] == 2:
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yield from self.doDelete(text, offset)
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elif entry["type"] == 3:
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yield from self.doHighlightRange(
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text, entry["highlightRanges"], offset
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)
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elif entry["type"] == 4:
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self.par_move_dict[entry["moveInfo"]["id"]] = entry
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# we need to count the tokens in the from revision so token index is correct
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self.n_from_end_tokens += len(self.tokenize(entry['text'].encode()))
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self.n_from_start_tokens += len(self.tokenize(entry['text'].encode()))
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elif entry["type"] == 5:
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yield from self.doParMove(entry)
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else:
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# The 'type' isn't one of the known
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raise ValueError(d)
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# mwpersistence expects differences to be represented in order from the
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# result's perspective ("to"), not the previous text. Thus, if a line
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# is moved earlier then its insertion should appear before its deletion.
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# As a rule of thumb, the "to" segments should be non-overlapping and
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# strictly increasing, while the "from" segments should merely be
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# non-overlapping.
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def doEqual(self, equal_text, offset):
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equal_bytes = equal_text.encode()
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tokens = self.tokenize(equal_bytes)
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n_tokens = len(tokens)
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self.n_from_end_tokens = self.n_from_start_tokens + n_tokens
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self.n_to_end_tokens = self.n_to_start_tokens + n_tokens
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# we need to keep track of the to and from last end bytes
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self.from_last_end_bytes = offset["from"] + len(equal_bytes)
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self.to_last_end_bytes = offset["to"] + len(equal_bytes)
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yield (
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Equal(
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self.n_from_start_tokens,
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self.n_from_end_tokens,
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self.n_to_start_tokens,
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self.n_to_end_tokens,
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),
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tokens,
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tokens,
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)
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self.n_from_start_tokens += n_tokens
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self.n_to_start_tokens += n_tokens
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self.from_byte_token_index_map[
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offset['from']
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] = self.n_from_end_tokens
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self.to_byte_token_index_map[offset['to']] = self.n_to_end_tokens
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def doInsert(self, insert_text, offset):
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insert_bytes = insert_text.encode()
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tokens = self.tokenize(insert_bytes)
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n_tokens = len(tokens)
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self.n_to_end_tokens = self.n_to_start_tokens + n_tokens
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self.to_last_end_bytes = offset["to"] + len(insert_bytes)
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yield (
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Insert(
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self.n_from_start_tokens,
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self.n_from_start_tokens,
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self.n_to_start_tokens,
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self.n_to_end_tokens,
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),
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[],
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tokens,
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)
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# We have now used more of the "to" tokens.
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self.n_to_start_tokens += n_tokens
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self.to_byte_token_index_map[offset['to']] = self.n_to_end_tokens
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def doDelete(self, delete_text, offset):
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delete_bytes = delete_text.encode()
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tokens = self.tokenize(delete_bytes)
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n_tokens = len(tokens)
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self.n_from_end_tokens = self.n_from_start_tokens + n_tokens
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self.from_last_end_bytes = offset["from"] + len(delete_bytes)
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yield (
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Delete(
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self.n_from_start_tokens,
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self.n_from_end_tokens,
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self.n_to_start_tokens,
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self.n_to_start_tokens,
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),
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tokens,
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[],
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)
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# We have now used more of the "from" tokens.
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self.n_from_start_tokens += n_tokens
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self.from_byte_token_index_map[
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offset['from']
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] = self.n_from_end_tokens
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def doHighlightRange(self, highlight_bytes, highlightRanges, offset):
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# The text field is an overlapping mix of both the from and to,
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# so we need to handle it highlight-by-highlight.
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# there can be gaps between highlight segments.
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# for instance, if a word is deleted from the middle of a line.
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# we need to track that.
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highlight_end = 0
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highlight_offset = offset
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# note that diffs are token-level, but the indexes are byte-level
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for highlightRange in highlightRanges:
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highlight_start = highlightRange["start"]
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# equal bytes in between highlights
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if highlight_start > highlight_end:
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equal_bytes = highlight_bytes[highlight_end:highlight_start]
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n_equal_bytes = len(equal_bytes)
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yield from self.doEqual(equal_bytes, highlight_offset)
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highlight_offset["from"] += n_equal_bytes
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highlight_offset["to"] += n_equal_bytes
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# handle highlighted insert / delete
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highlight_end = highlight_start + highlightRange["length"]
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range_bytes = highlight_bytes[highlight_start:highlight_end]
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n_range_bytes = len(range_bytes)
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if highlightRange["type"] == 0:
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yield from self.doInsert(range_bytes, highlight_offset)
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highlight_offset["to"] += n_range_bytes
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elif highlightRange["type"] == 1:
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yield from self.doDelete(range_bytes, highlight_offset)
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highlight_offset["from"] += n_range_bytes
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else:
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raise Exception(entry)
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# handle the rest of the line which is equal
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if highlight_end < len(highlight_bytes):
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range_bytes = highlight_bytes[highlight_end:]
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yield from self.doEqual(range_bytes, highlight_offset)
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def doParMove(self, to_diff):
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# the tricky part here is to put the tokens in the right spots.
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from_diff = self.par_move_dict[to_diff["moveInfo"]["linkId"]]
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from_byte_start = from_diff["offset"]["from"]
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# as of python 3.7 dictionaries are in insertion order. So
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# we can just find the first key that's greater
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# since the paragraph is removed in the "from" version, the index it is removed from
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# will be *after* the
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if from_byte_start >= self.from_last_end_bytes: # if the from paragraph is at the end
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from_token_start = next(reversed(self.from_byte_token_index_map.values()))
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else:
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key = find_greatest_le_key(from_byte_start, self.from_byte_token_index_map)
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from_token_start = self.from_byte_token_index_map[key]
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# get the to token index
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to_byte_start = to_diff["offset"]["to"]
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if to_byte_start >= self.to_last_end_bytes:
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to_token_start = next(reversed(self.to_byte_token_index_map.values()))
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else:
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key = find_greatest_le_key(to_byte_start, self.to_byte_token_index_map)
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to_token_start = self.to_byte_token_index_map[key]
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# now we set the state and apply the highlights
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self.n_from_start_tokens = self.n_from_end_tokens = from_token_start
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self.n_to_start_tokens = self.n_to_end_tokens = to_token_start
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offset = {"from": from_byte_start, "to": to_byte_start}
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yield from self.doHighlightRange(
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to_diff["text"], to_diff["highlightRanges"], offset
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)
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class WikiDiffMatcher:
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def __init__(
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self,
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texts: list[str] = None,
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tokenizer: Optional[RegexTokenizer] = None,
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url: Optional[str] = "http://127.0.0.1:8000",
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):
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# Pre-compute diffs to reduce traffic overhead.
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self.diffs = compute_diffs(url, texts)
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self.tokenizer = tokenizer or TOKENIZER
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class Processor(DiffEngine.Processor):
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def __init__(self, texts, tokenizer=None):
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self.diffs = iter(texts)
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self.tokenizer = tokenizer or TOKENIZER
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self.last_tokens = []
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self.previous_text = ""
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def update(self, last_tokens):
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self.last_tokens = last_tokens
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def process(self, text, token_class=None):
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# The diff has already been computed, but we need to incrementally
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# retrieve it to recreate the behavior DiffState expects.
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diff = next(self.diffs)
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diffToOperationsMapper = DiffToOperationMap(
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diff, self.tokenizer
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)
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(
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operations,
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aseq,
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bseq,
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) = list(zip(*diffToOperationsMapper.to_operations()))
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aseq = list(aseq)
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# aseq can be out of order, we need to sort it by a1 index.
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indices = list(range(len(aseq)))
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indices.sort(key = lambda i: operations[i].a1)
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aseq = [aseq[i] for i in indices]
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# bseq cannot be out of order since diffs are resolved in the order of aseq.
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self.last_tokens = list(chain.from_iterable(aseq))
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tokens = list(chain.from_iterable(bseq))
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self.previous_text = text
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return operations, self.last_tokens, tokens
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def processor(self, *args, **kwargs):
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return self.Processor(self.diffs, self.tokenizer)
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def process(self):
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# DiffState checks for this method even though it is not called.
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raise Exception("Unnecessary implementation")
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