src/changes.C

   1 /**
   2  * \file changes.C
   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. To avoid that every keystroke results in a separate change, a
  34  * tolerance interval of 5 minutes is used. That means if there are two adjacent
  35  * changes that only differ in their change time with abs(ct1 - ct2) < 300 sec,
  36  * they will be merged (and the later change time is preserved).
  37  * Technically, the check for equality (or similarity) is made in operator==(...).
  38  * The merging of similar changes happens in method merge().
  39  */
  40
  41 bool operator==(Change const & l, Change const & r)
  42 {
  43         if (l.type != r.type) {
  44                 return false;
  45         }
  46
  47         if (l.type == Change::UNCHANGED) {
  48                 return true;
  49         }
  50
  51         return l.author == r.author
  52                // both changes made within 5 minutes?
  53                && abs(difftime(l.changetime, r.changetime)) < 300;
  54 }
  55
  56
  57 bool operator!=(Change const & l, Change const & r)
  58 {
  59         return !(l == r);
  60 }
  61
  62
  63 bool operator==(Changes::Range const & r1, Changes::Range const & r2)
  64 {
  65         return r1.start == r2.start && r1.end == r2.end;
  66 }
  67
  68
  69 bool operator!=(Changes::Range const & r1, Changes::Range const & r2)
  70 {
  71         return !(r1 == r2);
  72 }
  73
  74
  75 bool Changes::Range::contains(Range const & r) const
  76 {
  77         return r.start >= start && r.end <= end;
  78 }
  79
  80
  81 bool Changes::Range::contains(pos_type const pos) const
  82 {
  83         return pos >= start && pos < end;
  84 }
  85
  86
  87 bool Changes::Range::intersects(Range const & r) const
  88 {
  89         return r.start < end && r.end > start; // end itself is not in the range!
  90 }
  91
  92
  93 void Changes::set(Change const & change, pos_type const pos)
  94 {
  95         set(change, pos, pos + 1);
  96 }
  97
  98
  99 void Changes::set(Change const & change, pos_type const start, pos_type const end)
 100 {
 101         if (lyxerr.debugging(Debug::CHANGES)) {
 102                 lyxerr[Debug::CHANGES] << "setting change (type: " << change.type
 103                         << ", author: " << change.author << ", time: " << change.changetime
 104                         << ") in range (" << start << ", " << end << ")" << endl;
 105         }
 106
 107         Range const newRange(start, end);
 108
 109         ChangeTable::iterator it = table_.begin();
 110
 111         for (; it != table_.end(); ) {
 112                 // current change starts like or follows new change
 113                 if (it->range.start >= start) {
 114                         break;
 115                 }
 116
 117                 // new change intersects with existing change
 118                 if (it->range.end > start) {
 119                         pos_type oldEnd = it->range.end;
 120                         it->range.end = start;
 121                         if (lyxerr.debugging(Debug::CHANGES)) {
 122                                 lyxerr[Debug::CHANGES] << "  cutting tail of type " << it->change.type
 123                                         << " resulting in range (" << it->range.start << ", "
 124                                         << it->range.end << ")" << endl;
 125                         }
 126                         ++it;
 127                         if (oldEnd >= end) {
 128                                 if (lyxerr.debugging(Debug::CHANGES)) {
 129                                         lyxerr[Debug::CHANGES] << "  inserting tail in range ("
 130                                                 << end << ", " << oldEnd << ")" << endl;
 131                                 }
 132                                 it = table_.insert(it, ChangeRange((it-1)->change, Range(end, oldEnd)));
 133                         }
 134                         continue;
 135                 }
 136
 137                 ++it;
 138         }
 139
 140         if (change.type != Change::UNCHANGED) {
 141                 if (lyxerr.debugging(Debug::CHANGES)) {
 142                         lyxerr[Debug::CHANGES] << "  inserting change" << endl;
 143                 }
 144                 it = table_.insert(it, ChangeRange(change, Range(start, end)));
 145                 ++it;
 146         }
 147
 148         for (; it != table_.end(); ) {
 149                 // new change 'contains' existing change
 150                 if (newRange.contains(it->range)) {
 151                         if (lyxerr.debugging(Debug::CHANGES)) {
 152                                 lyxerr[Debug::CHANGES] << "  removing subrange ("
 153                                         << it->range.start << ", " << it->range.end << ")" << endl;
 154                         }
 155                         it = table_.erase(it);
 156                         continue;
 157                 }
 158
 159                 // new change precedes existing change
 160                 if (it->range.start >= end) {
 161                         break;
 162                 }
 163
 164                 // new change intersects with existing change
 165                 it->range.start = end;
 166                 if (lyxerr.debugging(Debug::CHANGES)) {
 167                         lyxerr[Debug::CHANGES] << "  cutting head of type "
 168                                 << it->change.type << " resulting in range ("
 169                                 << end << ", " << it->range.end << ")" << endl;
 170                 }
 171                 break; // no need for another iteration
 172         }
 173
 174         merge();
 175 }
 176
 177
 178 void Changes::erase(pos_type const pos)
 179 {
 180         if (lyxerr.debugging(Debug::CHANGES)) {
 181                 lyxerr[Debug::CHANGES] << "Erasing change at position " << pos << endl;
 182         }
 183
 184         ChangeTable::iterator it = table_.begin();
 185         ChangeTable::iterator end = table_.end();
 186
 187         for (; it != end; ++it) {
 188                 // range (pos,pos+x) becomes (pos,pos+x-1)
 189                 if (it->range.start > pos) {
 190                         --(it->range.start);
 191                 }
 192                 // range (pos-x,pos) stays (pos-x,pos)
 193                 if (it->range.end > pos) {
 194                         --(it->range.end);
 195                 }
 196         }
 197
 198         merge();
 199 }
 200
 201
 202 void Changes::insert(Change const & change, lyx::pos_type pos)
 203 {
 204         if (lyxerr.debugging(Debug::CHANGES)) {
 205                 lyxerr[Debug::CHANGES] << "Inserting change of type " << change.type
 206                         << " at position " << pos << endl;
 207         }
 208
 209         ChangeTable::iterator it = table_.begin();
 210         ChangeTable::iterator end = table_.end();
 211
 212         for (; it != end; ++it) {
 213                 // range (pos,pos+x) becomes (pos+1,pos+x+1)
 214                 if (it->range.start >= pos) {
 215                         ++(it->range.start);
 216                 }
 217
 218                 // range (pos-x,pos) stays as it is
 219                 if (it->range.end > pos) {
 220                         ++(it->range.end);
 221                 }
 222         }
 223
 224         set(change, pos, pos + 1); // set will call merge
 225 }
 226
 227
 228 Change const Changes::lookup(pos_type const pos) const
 229 {
 230         if (table_.empty()) {
 231                 return Change(Change::UNCHANGED);
 232         }
 233         ChangeTable::const_iterator it = table_.begin();
 234         ChangeTable::const_iterator const end = table_.end();
 235
 236         for (; it != end; ++it) {
 237                 if (it->range.contains(pos))
 238                         return it->change;
 239         }
 240
 241         return Change(Change::UNCHANGED);
 242 }
 243
 244
 245 bool Changes::isChanged(pos_type const start, pos_type const end) const
 246 {
 247         ChangeTable::const_iterator it = table_.begin();
 248         ChangeTable::const_iterator const itend = table_.end();
 249
 250         for (; it != itend; ++it) {
 251                 if (it->range.intersects(Range(start, end))) {
 252                         if (lyxerr.debugging(Debug::CHANGES)) {
 253                                 lyxerr[Debug::CHANGES] << "found intersection of range ("
 254                                         << start << ", " << end << ") with ("
 255                                         << it->range.start << ", " << it->range.end
 256                                         << ") of type " << it->change.type << endl;
 257                         }
 258                         return true;
 259                 }
 260         }
 261         return false;
 262 }
 263
 264
 265 void Changes::merge()
 266 {
 267         if (lyxerr.debugging(Debug::CHANGES)) {
 268                 lyxerr[Debug::CHANGES] << "merging changes..." << endl;
 269         }
 270
 271         ChangeTable::iterator it = table_.begin();
 272
 273         while (it != table_.end()) {
 274                 if (lyxerr.debugging(Debug::CHANGES)) {
 275                         lyxerr[Debug::CHANGES] << "  found change of type " << it->change.type
 276                                 << " and range (" << it->range.start << ", " << it->range.end
 277                                 << ")" << endl;
 278                 }
 279
 280                 if (it->range.start == it->range.end) {
 281                         if (lyxerr.debugging(Debug::CHANGES)) {
 282                                 lyxerr[Debug::CHANGES] << "  removing empty range for pos "
 283                                         << it->range.start << endl;
 284                         }
 285
 286                         table_.erase(it);
 287                         // start again
 288                         it = table_.begin();
 289                         continue;
 290                 }
 291
 292                 if (it + 1 == table_.end())
 293                         break;
 294
 295                 if (it->change == (it + 1)->change && it->range.end == (it + 1)->range.start) {
 296                         if (lyxerr.debugging(Debug::CHANGES)) {
 297                                 lyxerr[Debug::CHANGES] << "  merging ranges (" << it->range.start << ", "
 298                                         << it->range.end << ") and (" << (it + 1)->range.start << ", "
 299                                         << (it + 1)->range.end << ")" << endl;
 300                         }
 301                         (it + 1)->range.start = it->range.start;
 302                         (it + 1)->change.changetime = max(it->change.changetime,
 303                                                           (it + 1)->change.changetime);
 304                         table_.erase(it);
 305                         // start again
 306                         it = table_.begin();
 307                         continue;
 308                 }
 309
 310                 ++it;
 311         }
 312 }
 313
 314
 315 int Changes::latexMarkChange(odocstream & os,
 316                              Change::Type const oldChangeType, Change::Type const changeType,
 317                              bool const & output)
 318 {
 319         if (!output || oldChangeType == changeType)
 320                 return 0;
 321
 322         static docstring const start(from_ascii("\\changestart{}"));
 323         static docstring const end(from_ascii("\\changeend{}"));
 324         static docstring const son(from_ascii("\\overstrikeon{}"));
 325         static docstring const soff(from_ascii("\\overstrikeoff{}"));
 326
 327         int column = 0;
 328
 329         if (oldChangeType == Change::DELETED) {
 330                 os << soff;
 331                 column += soff.length();
 332         }
 333
 334         switch (changeType) {
 335                 case Change::UNCHANGED:
 336                         os << end;
 337                         column += end.length();
 338                         break;
 339
 340                 case Change::DELETED:
 341                         if (oldChangeType == Change::UNCHANGED) {
 342                                 os << start;
 343                                 column += start.length();
 344                         }
 345                         os << son;
 346                         column += son.length();
 347                         break;
 348
 349                 case Change::INSERTED:
 350                         if (oldChangeType == Change::UNCHANGED) {
 351                                 os << start;
 352                                 column += start.length();
 353                         }
 354                         break;
 355         }
 356
 357         return column;
 358 }
 359
 360
 361 void Changes::lyxMarkChange(std::ostream & os, int & column,
 362                             Change const & old, Change const & change)
 363 {
 364         if (old == change)
 365                 return;
 366
 367         column = 0;
 368
 369         switch (change.type) {
 370                 case Change::UNCHANGED:
 371                         os << "\n\\change_unchanged\n";
 372                         break;
 373
 374                 case Change::DELETED: {
 375                         os << "\n\\change_deleted " << change.author
 376                                 << " " << change.changetime << "\n";
 377                         break;
 378                 }
 379
 380                 case Change::INSERTED: {
 381                         os << "\n\\change_inserted " << change.author
 382                                 << " " << change.changetime << "\n";
 383                         break;
 384                 }
 385         }
 386 }
 387
 388
 389 } // namespace lyx