File: surrounding_text_util.cc

package info (click to toggle)
mozc 2.23.2815.102+dfsg-4
  • links: PTS, VCS
  • area: main
  • in suites: buster
  • size: 138,784 kB
  • sloc: cpp: 223,701; java: 46,355; xml: 32,265; python: 8,557; lisp: 2,184; ansic: 763; sh: 121; yacc: 93; makefile: 83
file content (242 lines) | stat: -rw-r--r-- 7,561 bytes parent folder | download | duplicates (3)
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
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
// Copyright 2010-2013, Google Inc.
// All rights reserved.
//
// Redistribution and use in source and binary forms, with or without
// modification, are permitted provided that the following conditions are
// met:
//
//     * Redistributions of source code must retain the above copyright
// notice, this list of conditions and the following disclaimer.
//     * Redistributions in binary form must reproduce the above
// copyright notice, this list of conditions and the following disclaimer
// in the documentation and/or other materials provided with the
// distribution.
//     * Neither the name of Google Inc. nor the names of its
// contributors may be used to endorse or promote products derived from
// this software without specific prior written permission.
//
// THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
// "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
// LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
// A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
// OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
// SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
// LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
// DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
// THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
// (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
// OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.

#include "unix/fcitx/surrounding_text_util.h"

#include <limits>
#include <string>
#include <fcitx/instance.h>
#include <fcitx/module/clipboard/fcitx-clipboard.h>

#include "base/port.h"
#include "base/logging.h"
#include "base/util.h"

namespace mozc {
namespace fcitx {

bool SurroundingTextUtil::GetSafeDelta(uint from, uint to, int32 *delta) {
  DCHECK(delta);

  static_assert(sizeof(int64) >= sizeof(uint),
                "int64 must be sufficient to store a guint value.");
  static_assert(sizeof(int64) == sizeof(llabs(0)),
                "|llabs(0)| must returns a 64-bit integer.");
  const int64 kInt32AbsMax =
      llabs(static_cast<int64>(std::numeric_limits<int32>::max()));
  const int64 kInt32AbsMin =
      llabs(static_cast<int64>(std::numeric_limits<int32>::min()));
  const int64 kInt32SafeAbsMax =
      std::min(kInt32AbsMax, kInt32AbsMin);

  const int64 diff = static_cast<int64>(from) - static_cast<int64>(to);
  if (llabs(diff) > kInt32SafeAbsMax) {
    return false;
  }

  *delta = static_cast<int32>(diff);
  return true;
}

namespace {

// Moves |iter| with |skip_count| characters.
// Returns false if |iter| reaches to the end before skipping
// |skip_count| characters.
bool Skip(ConstChar32Iterator *iter, size_t skip_count) {
  for (size_t i = 0; i < skip_count; ++i) {
    if (iter->Done()) {
      return false;
    }
    iter->Next();
  }
  return true;
}

// Returns true if |prefix_iter| is the prefix of |iter|.
// Returns false if |prefix_iter| is an empty sequence.
// Otherwise returns false.
// This function receives ConstChar32Iterator as pointer because
// ConstChar32Iterator is defined as non-copyable.
bool StartsWith(ConstChar32Iterator *iter,
                ConstChar32Iterator *prefix_iter) {
  if (iter->Done() || prefix_iter->Done()) {
    return false;
  }

  while (true) {
    if (iter->Get() != prefix_iter->Get()) {
      return false;
    }
    prefix_iter->Next();
    if (prefix_iter->Done()) {
      return true;
    }
    iter->Next();
    if (iter->Done()) {
      return false;
    }
  }
}


// Returns true if |surrounding_text| contains |selected_text|
// from |cursor_pos| to |*anchor_pos|.
// Otherwise returns false.
bool SearchAnchorPosForward(
    const string &surrounding_text,
    const string &selected_text,
    size_t selected_chars_len,
    uint cursor_pos,
    uint *anchor_pos) {

  ConstChar32Iterator iter(surrounding_text);
  // Move |iter| to cursor pos.
  if (!Skip(&iter, cursor_pos)) {
    return false;
  }

  ConstChar32Iterator sel_iter(selected_text);
  if (!StartsWith(&iter, &sel_iter)) {
    return false;
  }
  *anchor_pos = cursor_pos + selected_chars_len;
  return true;
}

// Returns true if |surrounding_text| contains |selected_text|
// from |*anchor_pos| to |cursor_pos|.
// Otherwise returns false.
bool SearchAnchorPosBackward(
    const string &surrounding_text,
    const string &selected_text,
    size_t selected_chars_len,
    uint cursor_pos,
    uint *anchor_pos) {
  if (cursor_pos < selected_chars_len) {
    return false;
  }

  ConstChar32Iterator iter(surrounding_text);
  // Skip |iter| to (potential) anchor pos.
  const uint skip_count = cursor_pos - selected_chars_len;
  DCHECK_LE(skip_count, cursor_pos);
  if (!Skip(&iter, skip_count)) {
    return false;
  }

  ConstChar32Iterator sel_iter(selected_text);
  if (!StartsWith(&iter, &sel_iter)) {
    return false;
  }
  *anchor_pos = cursor_pos - selected_chars_len;
  return true;
}

}  // namespace

bool SurroundingTextUtil::GetAnchorPosFromSelection(
    const string &surrounding_text,
    const string &selected_text,
    uint cursor_pos,
    uint *anchor_pos) {
  DCHECK(anchor_pos);

  if (surrounding_text.empty()) {
    return false;
  }

  if (selected_text.empty()) {
    return false;
  }

  const size_t selected_chars_len = Util::CharsLen(selected_text);

  if (SearchAnchorPosForward(surrounding_text, selected_text,
                             selected_chars_len,
                             cursor_pos, anchor_pos)) {
    return true;
  }

  return SearchAnchorPosBackward(surrounding_text, selected_text,
                                 selected_chars_len,
                                 cursor_pos, anchor_pos);
}

bool GetSurroundingText(FcitxInstance* instance,
                        SurroundingTextInfo *info) {
    FcitxInputContext* ic = FcitxInstanceGetCurrentIC(instance);
    if (!ic || !(ic->contextCaps & CAPACITY_SURROUNDING_TEXT)) {
        return false;
    }

    uint cursor_pos = 0;
    uint anchor_pos = 0;
    char* str = NULL;

    if (!FcitxInstanceGetSurroundingText(instance, ic, &str, &cursor_pos, &anchor_pos)) {
        return false;
    }

    const string surrounding_text(str);
    free(str);

    if (cursor_pos == anchor_pos) {
        const char* primary = NULL;

        if ((primary = FcitxClipboardGetPrimarySelection(instance, NULL)) != NULL) {
            uint new_anchor_pos = 0;
            const string primary_text(primary);
            if (SurroundingTextUtil::GetAnchorPosFromSelection(
                surrounding_text, primary_text,
                cursor_pos, &new_anchor_pos)) {
                anchor_pos = new_anchor_pos;
            }
        }
    }

    if (!SurroundingTextUtil::GetSafeDelta(cursor_pos, anchor_pos,
                                           &info->relative_selected_length)) {
        LOG(ERROR) << "Too long text selection.";
        return false;
    }

    const size_t selection_start = std::min(cursor_pos, anchor_pos);
    const size_t selection_length = std::abs(info->relative_selected_length);
    Util::SubStringPiece(surrounding_text, 0, selection_start)
       .CopyToString(&info->preceding_text);
    Util::SubStringPiece(surrounding_text, selection_start, selection_length)
       .CopyToString(&info->selection_text);
    Util::SubStringPiece(surrounding_text, selection_start + selection_length)
       .CopyToString(&info->following_text);
    return true;
}

}  // namespace fcitx
}  // namespace mozc