src/Changes.cpp

   1 /**
   2  * \file Changes.cpp
   3  * This file is part of LyX, the document processor.
   4  * Licence details can be found in the file COPYING.
   5  *
   6  * \author John Levon
   7  * \author Michael Gerz
   8  *
   9  * Full author contact details are available in file CREDITS.
  10  *
  11  * Record changes in a paragraph.
  12  */
  13
  14 #include <config.h>
  15
  16 #include "Changes.h"
  17 #include "debug.h"
  18
  19 #include <boost/assert.hpp>
  20
  21
  22 namespace lyx {
  23
  24 using std::abs;
  25 using std::endl;
  26 using std::string;
  27 using std::max;
  28
  29 /*
  30  * Class Change has a changetime field that specifies the exact time at which
  31  * a specific change was made. The change time is used as a guidance for the
  32  * user while editing his document. Presently, it is not considered for LaTeX
  33  * export.
  34  * When merging two adjacent changes, the changetime is not considered,
  35  * only the equality of the change type and author is checked (in method
  36  * isSimilarTo(...)). If two changes are in fact merged (in method merge()),
  37  * the later change time is preserved.
  38  */
  39
  40 bool Change::isSimilarTo(Change const & change)
  41 {
  42         if (type != change.type) {
  43                 return false;
  44         }
  45
  46         if (type == Change::UNCHANGED) {
  47                 return true;
  48         }
  49
  50         return author == change.author;
  51 }
  52
  53
  54 bool operator==(Change const & l, Change const & r)
  55 {
  56         if (l.type != r.type) {
  57                 return false;
  58         }
  59
  60         // two changes of type UNCHANGED are always equal
  61         if (l.type == Change::UNCHANGED) {
  62                 return true;
  63         }
  64
  65         return l.author == r.author &&
  66                l.changetime == r.changetime;
  67 }
  68
  69
  70 bool operator!=(Change const & l, Change const & r)
  71 {
  72         return !(l == r);
  73 }
  74
  75
  76 bool operator==(Changes::Range const & r1, Changes::Range const & r2)
  77 {
  78         return r1.start == r2.start && r1.end == r2.end;
  79 }
  80
  81
  82 bool operator!=(Changes::Range const & r1, Changes::Range const & r2)
  83 {
  84         return !(r1 == r2);
  85 }
  86
  87
  88 bool Changes::Range::intersects(Range const & r) const
  89 {
  90         return r.start < end && r.end > start; // end itself is not in the range!
  91 }
  92
  93
  94 void Changes::set(Change const & change, pos_type const pos)
  95 {
  96         set(change, pos, pos + 1);
  97 }
  98
  99
 100 void Changes::set(Change const & change, pos_type const start, pos_type const end)
 101 {
 102         if (change.type != Change::UNCHANGED) {
 103                 LYXERR(Debug::CHANGES) << "setting change (type: " << change.type
 104                         << ", author: " << change.author << ", time: " << change.changetime
 105                         << ") in range (" << start << ", " << end << ")" << endl;
 106         }
 107
 108         Range const newRange(start, end);
 109
 110         ChangeTable::iterator it = table_.begin();
 111
 112         for (; it != table_.end(); ) {
 113                 // current change starts like or follows new change
 114                 if (it->range.start >= start) {
 115                         break;
 116                 }
 117
 118                 // new change intersects with existing change
 119                 if (it->range.end > start) {
 120                         pos_type oldEnd = it->range.end;
 121                         it->range.end = start;
 122
 123                         LYXERR(Debug::CHANGES) << "  cutting tail of type " << it->change.type
 124                                 << " resulting in range (" << it->range.start << ", "
 125                                 << it->range.end << ")" << endl;
 126
 127                         ++it;
 128                         if (oldEnd >= end) {
 129                                 LYXERR(Debug::CHANGES) << "  inserting tail in range ("
 130                                         << end << ", " << oldEnd << ")" << endl;
 131                                 it = table_.insert(it, ChangeRange((it-1)->change, Range(end, oldEnd)));
 132                         }
 133                         continue;
 134                 }
 135
 136                 ++it;
 137         }
 138
 139         if (change.type != Change::UNCHANGED) {
 140                 LYXERR(Debug::CHANGES) << "  inserting change" << endl;
 141                 it = table_.insert(it, ChangeRange(change, Range(start, end)));
 142                 ++it;
 143         }
 144
 145         for (; it != table_.end(); ) {
 146                 // new change 'contains' existing change
 147                 if (newRange.contains(it->range)) {
 148                         LYXERR(Debug::CHANGES) << "  removing subrange ("
 149                                 << it->range.start << ", " << it->range.end << ")" << endl;
 150                         it = table_.erase(it);
 151                         continue;
 152                 }
 153
 154                 // new change precedes existing change
 155                 if (it->range.start >= end) {
 156                         break;
 157                 }
 158
 159                 // new change intersects with existing change
 160                 it->range.start = end;
 161                 LYXERR(Debug::CHANGES) << "  cutting head of type "
 162                         << it->change.type << " resulting in range ("
 163                         << end << ", " << it->range.end << ")" << endl;
 164                 break; // no need for another iteration
 165         }
 166
 167         merge();
 168 }
 169
 170
 171 void Changes::erase(pos_type const pos)
 172 {
 173         LYXERR(Debug::CHANGES) << "Erasing change at position " << pos << endl;
 174
 175         ChangeTable::iterator it = table_.begin();
 176         ChangeTable::iterator end = table_.end();
 177
 178         for (; it != end; ++it) {
 179                 // range (pos,pos+x) becomes (pos,pos+x-1)
 180                 if (it->range.start > pos) {
 181                         --(it->range.start);
 182                 }
 183                 // range (pos-x,pos) stays (pos-x,pos)
 184                 if (it->range.end > pos) {
 185                         --(it->range.end);
 186                 }
 187         }
 188
 189         merge();
 190 }
 191
 192
 193 void Changes::insert(Change const & change, lyx::pos_type pos)
 194 {
 195         if (change.type != Change::UNCHANGED) {
 196                 LYXERR(Debug::CHANGES) << "Inserting change of type " << change.type
 197                         << " at position " << pos << endl;
 198         }
 199
 200         ChangeTable::iterator it = table_.begin();
 201         ChangeTable::iterator end = table_.end();
 202
 203         for (; it != end; ++it) {
 204                 // range (pos,pos+x) becomes (pos+1,pos+x+1)
 205                 if (it->range.start >= pos) {
 206                         ++(it->range.start);
 207                 }
 208
 209                 // range (pos-x,pos) stays as it is
 210                 if (it->range.end > pos) {
 211                         ++(it->range.end);
 212                 }
 213         }
 214
 215         set(change, pos, pos + 1); // set will call merge
 216 }
 217
 218
 219 Change const & Changes::lookup(pos_type const pos) const
 220 {
 221         static Change const noChange = Change(Change::UNCHANGED);
 222
 223         ChangeTable::const_iterator it = table_.begin();
 224         ChangeTable::const_iterator const end = table_.end();
 225
 226         for (; it != end; ++it) {
 227                 if (it->range.contains(pos))
 228                         return it->change;
 229         }
 230
 231         return noChange;
 232 }
 233
 234
 235 bool Changes::isChanged(pos_type const start, pos_type const end) const
 236 {
 237         ChangeTable::const_iterator it = table_.begin();
 238         ChangeTable::const_iterator const itend = table_.end();
 239
 240         for (; it != itend; ++it) {
 241                 if (it->range.intersects(Range(start, end))) {
 242                         LYXERR(Debug::CHANGES) << "found intersection of range ("
 243                                 << start << ", " << end << ") with ("
 244                                 << it->range.start << ", " << it->range.end
 245                                 << ") of type " << it->change.type << endl;
 246                         return true;
 247                 }
 248         }
 249         return false;
 250 }
 251
 252
 253 void Changes::merge()
 254 {
 255         ChangeTable::iterator it = table_.begin();
 256
 257         while (it != table_.end()) {
 258                 LYXERR(Debug::CHANGES) << "found change of type " << it->change.type
 259                         << " and range (" << it->range.start << ", " << it->range.end
 260                         << ")" << endl;
 261
 262                 if (it->range.start == it->range.end) {
 263                         LYXERR(Debug::CHANGES) << "removing empty range for pos "
 264                                 << it->range.start << endl;
 265
 266                         table_.erase(it);
 267                         // start again
 268                         it = table_.begin();
 269                         continue;
 270                 }
 271
 272                 if (it + 1 == table_.end())
 273                         break;
 274
 275                 if (it->change.isSimilarTo((it + 1)->change) && it->range.end == (it + 1)->range.start) {
 276                         LYXERR(Debug::CHANGES) << "merging ranges (" << it->range.start << ", "
 277                                 << it->range.end << ") and (" << (it + 1)->range.start << ", "
 278                                 << (it + 1)->range.end << ")" << endl;
 279
 280                         (it + 1)->range.start = it->range.start;
 281                         (it + 1)->change.changetime = max(it->change.changetime,
 282                                                           (it + 1)->change.changetime);
 283                         table_.erase(it);
 284                         // start again
 285                         it = table_.begin();
 286                         continue;
 287                 }
 288
 289                 ++it;
 290         }
 291 }
 292
 293
 294 int Changes::latexMarkChange(odocstream & os,
 295                              Change::Type const oldChangeType, Change::Type const changeType,
 296                              bool const & output)
 297 {
 298         if (!output || oldChangeType == changeType)
 299                 return 0;
 300
 301         static docstring const start(from_ascii("\\changestart{}"));
 302         static docstring const end(from_ascii("\\changeend{}"));
 303         static docstring const son(from_ascii("\\overstrikeon{}"));
 304         static docstring const soff(from_ascii("\\overstrikeoff{}"));
 305
 306         int column = 0;
 307
 308         if (oldChangeType == Change::DELETED) {
 309                 os << soff;
 310                 column += soff.length();
 311         }
 312
 313         switch (changeType) {
 314                 case Change::UNCHANGED:
 315                         os << end;
 316                         column += end.length();
 317                         break;
 318
 319                 case Change::DELETED:
 320                         if (oldChangeType == Change::UNCHANGED) {
 321                                 os << start;
 322                                 column += start.length();
 323                         }
 324                         os << son;
 325                         column += son.length();
 326                         break;
 327
 328                 case Change::INSERTED:
 329                         if (oldChangeType == Change::UNCHANGED) {
 330                                 os << start;
 331                                 column += start.length();
 332                         }
 333                         break;
 334         }
 335
 336         return column;
 337 }
 338
 339
 340 void Changes::lyxMarkChange(std::ostream & os, int & column,
 341                             Change const & old, Change const & change)
 342 {
 343         if (old == change)
 344                 return;
 345
 346         column = 0;
 347
 348         switch (change.type) {
 349                 case Change::UNCHANGED:
 350                         os << "\n\\change_unchanged\n";
 351                         break;
 352
 353                 case Change::DELETED: {
 354                         os << "\n\\change_deleted " << change.author
 355                                 << " " << change.changetime << "\n";
 356                         break;
 357                 }
 358
 359                 case Change::INSERTED: {
 360                         os << "\n\\change_inserted " << change.author
 361                                 << " " << change.changetime << "\n";
 362                         break;
 363                 }
 364         }
 365 }
 366
 367
 368 } // namespace lyx