File size: 5,338 Bytes
b6e5241
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
"""
Originally by https://worksheets.codalab.org/worksheets/0x8fc01c7fc2b742fdb29c05669f0ad7d2
"""
import json
import os, sys
import re
import random
import numpy as np
from random import sample
from tqdm import tqdm
from collections import Counter

from critic.edit_dist_utils import get_all_edit_dist_one, sample_random_internal_permutations


try:
    dir_path = os.path.dirname(os.path.realpath(__file__))
except:
    dir_path = '.'
common_typo = json.load(open(f"{dir_path}/common_typo.json"))

random.seed(1234)
np.random.seed(1234)


class RandomPerturbationAttack(object):
    def __init__(self, attack_type = 'ed1'):
        self.cache = {} #{word: {0: set(), 1: set(),.. }, ..} #0=swap, 1=substitute, 2=delete, 3=insert
        self.n_types = 5
        self.attack_type = attack_type
    #
    def sample_perturbations(self, word, n_samples, types):
        if types is None:
            type_list = list(range(4)) * (n_samples//4) + list(np.random.choice(self.n_types, n_samples % self.n_types, replace=False))
        else:
            type_list = [sample(types,1)[0] for _ in range(n_samples)]
        type_count = Counter(type_list)
        perturbations = set()
        for type in type_count:
            if type not in self.cache[word]:
                continue
            if len(self.cache[word][type]) >= type_count[type]:
                perturbations.update(set(sample(self.cache[word][type], type_count[type])))
            else:
                perturbations.update(self.cache[word][type])
        return perturbations
    #
    def get_perturbations(self, word, n_samples, types=None):
        if word not in self.cache:
            self.cache[word] = {}
            if word[0].islower():
                for type in range(4):
                    self.cache[word][type] = get_all_edit_dist_one(word, 10**type)
                if word in common_typo:
                    self.cache[word][4] = set(common_typo[word])
            elif word[0].isupper():
                if word in common_typo:
                    self.cache[word][4] = set(common_typo[word])
        if self.attack_type == 'ed1':
            perturbations = self.sample_perturbations(word, n_samples, types)
        else:
            raise NotImplementedError("Attack type: {} not implemented yet".format(self.attack_type))
        return perturbations
    #
    def name(self):
        return 'RandomPerturbationAttack'


word_attack = RandomPerturbationAttack()


def _tokenize(sent):
    toks = []
    word_idxs = []
    for idx, match in enumerate(re.finditer(r'([a-zA-Z]+)|([0-9]+)|.', sent)):
        tok = match.group(0)
        toks.append(tok)
        if len(tok) > 2 and tok.isalpha() and (tok[0].islower()):
            word_idxs.append(idx)
    return toks, word_idxs

def _detokenize(toks):
    return ''.join(toks)

def get_local_neighbors_char_level(sent, max_n_samples=500):
    words, word_idxs = _tokenize(sent)
    n_samples = min(len(word_idxs) *20, max_n_samples)
    sent_perturbations = set()
    if len(word_idxs) == 0:
        return sent_perturbations
    for _ in range(500):
        word_idx = sample(word_idxs, 1)[0]
        words_cp = words[:]
        word_perturbations = list(word_attack.get_perturbations(words_cp[word_idx], n_samples=1))
        if len(word_perturbations) > 0:
            words_cp[word_idx] = word_perturbations[0]
            sent_perturbed = _detokenize(words_cp)
            if sent_perturbed != sent:
                sent_perturbations.add(sent_perturbed)
        if len(sent_perturbations) == n_samples:
            break
    #Adding common typos such as 's'
    for word_idx in word_idxs:
        words_cp = words[:]
        word = words_cp[word_idx]
        if len(word) > 2 and word[0].islower():
            words_cp[word_idx] = word +'s'
            sent_perturbed = _detokenize(words_cp)
            if sent_perturbed != sent:
                sent_perturbations.add(sent_perturbed)
            words_cp[word_idx] = word[:-1]
            sent_perturbed = _detokenize(words_cp)
            if sent_perturbed != sent:
                sent_perturbations.add(sent_perturbed)
    if len(sent_perturbations) > max_n_samples:
        sent_perturbations = list(sent_perturbations)
        np.random.shuffle(sent_perturbations)
        sent_perturbations = set(sent_perturbations[:max_n_samples])
    return sent_perturbations



from critic.PIE.word_level_perturb import WordLevelPerturber_all, WordLevelPerturber_refine
from utils.text_utils import detokenize_sent

def get_local_neighbors_word_level(sent_toked, max_n_samples=500, mode='refine'):
    """ sent_toked is tokenized by spacy """
    n_samples = min(len(sent_toked) *20, max_n_samples)
    orig_sent = ' '.join(sent_toked)
    orig_sent_detok = detokenize_sent(orig_sent)
    if mode == 'refine':
        ptb = WordLevelPerturber_refine(orig_sent)
    else:
        ptb = WordLevelPerturber_all(orig_sent)
    sent_perturbations = set()
    for _ in range(500):
        sent_perturbed = ptb.perturb()
        if sent_perturbed != orig_sent:
            sent_perturbed_detok = detokenize_sent(sent_perturbed)
            sent_perturbations.add(sent_perturbed_detok)
        if len(sent_perturbations) == n_samples:
            break
    assert len(sent_perturbations) <= max_n_samples
    return sent_perturbations, orig_sent_detok