src/graphics/GraphicsLoader.cpp

   1 /**
   2  * \file GraphicsLoader.cpp
   3  * This file is part of LyX, the document processor.
   4  * Licence details can be found in the file COPYING.
   5  *
   6  * \author Angus Leeming
   7  *
   8  * Full author contact details are available in file CREDITS.
   9  */
  10
  11 #include <config.h>
  12
  13 #include "GraphicsLoader.h"
  14
  15 #include "GraphicsCacheItem.h"
  16 #include "GraphicsImage.h"
  17 #include "GraphicsParams.h"
  18 #include "GraphicsCache.h"
  19
  20 #include "support/debug.h"
  21 #include "support/Timeout.h"
  22
  23 #include <boost/bind.hpp>
  24
  25 #include <set>
  26 #include <queue>
  27
  28 using namespace std;
  29 using namespace lyx::support;
  30
  31 namespace lyx {
  32 namespace graphics {
  33
  34
  35 /////////////////////////////////////////////////////////////////////
  36 //
  37 // LoaderQueue
  38 //
  39 /////////////////////////////////////////////////////////////////////
  40
  41 class LoaderQueue {
  42 public:
  43         /// Use this to request that the item is loaded.
  44         void touch(Cache::ItemPtr const & item);
  45         /// Query whether the clock is ticking.
  46         bool running() const;
  47         ///get the and only instance of the class
  48         static LoaderQueue & get();
  49 private:
  50         /// This class is a singleton class... use LoaderQueue::get() instead
  51         LoaderQueue();
  52         /// The in-progress loading queue (elements are unique here).
  53         list<Cache::ItemPtr> cache_queue_;
  54         /// Used to make the insertion of new elements faster.
  55         set<Cache::ItemPtr> cache_set_;
  56         /// Newly touched elements go here. loadNext moves them to cache_queue_
  57         queue<Cache::ItemPtr> bucket_;
  58         ///
  59         Timeout timer;
  60         ///
  61         bool running_;
  62
  63         /** This is the 'threaded' method, that does the loading in the
  64          *  background.
  65          */
  66         void loadNext();
  67         ///
  68         void startLoader();
  69         ///
  70         void stopLoader();
  71 };
  72
  73
  74 //static int s_numimages_ = 5;
  75 //static int s_millisecs_ = 500;
  76
  77 static int s_numimages_ = 10;
  78 static int s_millisecs_ = 500;
  79
  80 LoaderQueue & LoaderQueue::get()
  81 {
  82         static LoaderQueue singleton;
  83         return singleton;
  84 }
  85
  86
  87 void LoaderQueue::loadNext()
  88 {
  89         LYXERR(Debug::GRAPHICS, "LoaderQueue: "
  90                 << cache_queue_.size() << " items in the queue");
  91         int counter = s_numimages_;
  92         while (cache_queue_.size() && counter--) {
  93                 Cache::ItemPtr ptr = cache_queue_.front();
  94                 cache_set_.erase(ptr);
  95                 cache_queue_.pop_front();
  96                 if (ptr->status() == WaitingToLoad)
  97                         ptr->startLoading();
  98         }
  99         if (cache_queue_.size()) {
 100                 startLoader();
 101         } else {
 102                 stopLoader();
 103         }
 104 }
 105
 106
 107 LoaderQueue::LoaderQueue() : timer(s_millisecs_, Timeout::ONETIME),
 108                              running_(false)
 109 {
 110         timer.timeout.connect(boost::bind(&LoaderQueue::loadNext, this));
 111 }
 112
 113
 114 void LoaderQueue::startLoader()
 115 {
 116         LYXERR(Debug::GRAPHICS, "LoaderQueue: waking up");
 117         running_ = true ;
 118         timer.setTimeout(s_millisecs_);
 119         timer.start();
 120 }
 121
 122
 123 void LoaderQueue::stopLoader()
 124 {
 125         timer.stop();
 126         running_ = false ;
 127         LYXERR(Debug::GRAPHICS, "LoaderQueue: I'm going to sleep");
 128 }
 129
 130
 131 bool LoaderQueue::running() const
 132 {
 133         return running_ ;
 134 }
 135
 136
 137 void LoaderQueue::touch(Cache::ItemPtr const & item)
 138 {
 139         if (! cache_set_.insert(item).second) {
 140                 list<Cache::ItemPtr>::iterator
 141                         it = cache_queue_.begin();
 142                 list<Cache::ItemPtr>::iterator
 143                         end = cache_queue_.end();
 144
 145                 it = find(it, end, item);
 146                 if (it != end)
 147                         cache_queue_.erase(it);
 148         }
 149         cache_queue_.push_front(item);
 150         if (!running_)
 151                 startLoader();
 152 }
 153
 154
 155
 156 /////////////////////////////////////////////////////////////////////
 157 //
 158 // GraphicsLoader
 159 //
 160 /////////////////////////////////////////////////////////////////////
 161
 162 typedef boost::shared_ptr<Image> ImagePtr;
 163
 164 class Loader::Impl : public boost::signals::trackable {
 165 public:
 166         ///
 167         Impl();
 168         ///
 169         ~Impl();
 170         ///
 171         void resetFile(FileName const &);
 172         ///
 173         void resetParams(Params const &);
 174         ///
 175         void createPixmap();
 176         ///
 177         void startLoading();
 178         ///
 179         Params const & params() const { return params_; }
 180
 181         /// The loading status of the image.
 182         ImageStatus status_;
 183         /** Must store a copy of the cached item to ensure that it is not
 184          *  erased unexpectedly by the cache itself.
 185          */
 186         Cache::ItemPtr cached_item_;
 187         /// We modify a local copy of the image once it is loaded.
 188         ImagePtr image_;
 189         /// This signal is emitted when the image loading status changes.
 190         boost::signal<void()> signal_;
 191         /// The connection of the signal StatusChanged
 192         boost::signals::connection sc_;
 193
 194 private:
 195         ///
 196         void statusChanged();
 197         ///
 198         void checkedLoading();
 199
 200         ///
 201         Params params_;
 202 };
 203
 204
 205 Loader::Loader()
 206         : pimpl_(new Impl)
 207 {}
 208
 209
 210 Loader::Loader(FileName const & file, bool display)
 211         : pimpl_(new Impl)
 212 {
 213         reset(file, display);
 214 }
 215
 216
 217 Loader::Loader(FileName const & file, Params const & params)
 218         : pimpl_(new Impl)
 219 {
 220         reset(file, params);
 221 }
 222
 223
 224 Loader::Loader(Loader const & other)
 225         : pimpl_(new Impl)
 226 {
 227         Params const & params = other.pimpl_->params();
 228         reset(params.filename, params);
 229 }
 230
 231
 232 Loader::~Loader()
 233 {
 234         delete pimpl_;
 235 }
 236
 237
 238 Loader & Loader::operator=(Loader const & other)
 239 {
 240         if (this != &other) {
 241                 Params const & params = other.pimpl_->params();
 242                 reset(params.filename, params);
 243         }
 244         return *this;
 245 }
 246
 247
 248 void Loader::reset(FileName const & file, bool display) const
 249 {
 250         Params params;
 251         params.display = display;
 252         pimpl_->resetParams(params);
 253
 254         pimpl_->resetFile(file);
 255         pimpl_->createPixmap();
 256 }
 257
 258
 259 void Loader::reset(FileName const & file, Params const & params) const
 260 {
 261         pimpl_->resetParams(params);
 262         pimpl_->resetFile(file);
 263         pimpl_->createPixmap();
 264 }
 265
 266
 267 void Loader::reset(Params const & params) const
 268 {
 269         pimpl_->resetParams(params);
 270         pimpl_->createPixmap();
 271 }
 272
 273
 274 void Loader::startLoading() const
 275 {
 276         if (pimpl_->status_ != WaitingToLoad || !pimpl_->cached_item_.get())
 277                 return;
 278         pimpl_->startLoading();
 279 }
 280
 281
 282 void Loader::reload() const
 283 {
 284         pimpl_->cached_item_->startLoading();
 285 }
 286
 287
 288 void Loader::startMonitoring() const
 289 {
 290         if (!pimpl_->cached_item_.get())
 291                 return;
 292
 293         pimpl_->cached_item_->startMonitoring();
 294 }
 295
 296
 297 bool Loader::monitoring() const
 298 {
 299         if (!pimpl_->cached_item_.get())
 300                 return false;
 301
 302         return pimpl_->cached_item_->monitoring();
 303 }
 304
 305
 306 unsigned long Loader::checksum() const
 307 {
 308         if (!pimpl_->cached_item_.get())
 309                 return 0;
 310
 311         return pimpl_->cached_item_->checksum();
 312 }
 313
 314
 315 FileName const & Loader::filename() const
 316 {
 317         static FileName const empty;
 318         return pimpl_->cached_item_.get() ?
 319                 pimpl_->cached_item_->filename() : empty;
 320 }
 321
 322
 323 ImageStatus Loader::status() const
 324 {
 325         return pimpl_->status_;
 326 }
 327
 328
 329 boost::signals::connection Loader::connect(slot_type const & slot) const
 330 {
 331         return pimpl_->signal_.connect(slot);
 332 }
 333
 334
 335 Image const * Loader::image() const
 336 {
 337         return pimpl_->image_.get();
 338 }
 339
 340
 341 Loader::Impl::Impl()
 342         : status_(WaitingToLoad)
 343 {
 344 }
 345
 346
 347 Loader::Impl::~Impl()
 348 {
 349         resetFile(FileName());
 350 }
 351
 352
 353 void Loader::Impl::resetFile(FileName const & file)
 354 {
 355         FileName const old_file = cached_item_.get() ?
 356                 cached_item_->filename() : FileName();
 357
 358         if (file == old_file)
 359                 return;
 360
 361         // If monitoring() the current file, should continue to monitor the
 362         // new file.
 363         bool continue_monitoring = false;
 364
 365         if (!old_file.empty()) {
 366                 continue_monitoring = cached_item_->monitoring();
 367                 // cached_item_ is going to be reset, so the connected
 368                 // signal needs to be disconnected.
 369                 sc_.disconnect();
 370                 cached_item_.reset();
 371                 Cache::get().remove(old_file);
 372         }
 373
 374         status_ = cached_item_.get() ? cached_item_->status() : WaitingToLoad;
 375         image_.reset();
 376
 377         if (cached_item_.get() || file.empty())
 378                 return;
 379
 380         Cache & gc = Cache::get();
 381         if (!gc.inCache(file))
 382                 gc.add(file);
 383
 384         // We /must/ make a local copy of this.
 385         cached_item_ = gc.item(file);
 386         status_ = cached_item_->status();
 387
 388         if (continue_monitoring && !cached_item_->monitoring())
 389                 cached_item_->startMonitoring();
 390
 391         sc_ = cached_item_->connect(boost::bind(&Impl::statusChanged, this));
 392 }
 393
 394
 395 void Loader::Impl::resetParams(Params const & params)
 396 {
 397         if (params == params_)
 398                 return;
 399
 400         params_ = params;
 401         status_ = cached_item_.get() ? cached_item_->status() : WaitingToLoad;
 402         image_.reset();
 403 }
 404
 405
 406 void Loader::Impl::statusChanged()
 407 {
 408         status_ = cached_item_.get() ? cached_item_->status() : WaitingToLoad;
 409         createPixmap();
 410         signal_();
 411 }
 412
 413
 414 void Loader::Impl::createPixmap()
 415 {
 416         if (!params_.display || status_ != Loaded)
 417                 return;
 418
 419         if (!cached_item_.get()) {
 420                 LYXERR(Debug::GRAPHICS, "pixmap not cached yet");
 421                 return;
 422         }
 423
 424         if (!cached_item_->image()) {
 425                 // There must have been a problem reading the file.
 426                 LYXERR(Debug::GRAPHICS, "Graphics file not loaded.");
 427                 return;
 428         }
 429
 430         image_.reset(cached_item_->image()->clone());
 431
 432         bool const success = image_->setPixmap(params_);
 433
 434         if (success) {
 435                 status_ = Ready;
 436         } else {
 437                 image_.reset();
 438                 status_ = ErrorGeneratingPixmap;
 439         }
 440 }
 441
 442 void Loader::Impl::startLoading()
 443 {
 444         if (status_ != WaitingToLoad)
 445                 return;
 446
 447         if (cached_item_->tryDisplayFormat()) {
 448                 status_ = Loaded;
 449                 createPixmap();
 450                 return;
 451         }
 452
 453         LoaderQueue::get().touch(cached_item_);
 454 }
 455
 456
 457 } // namespace graphics
 458 } // namespace lyx