webdvd.cpp

   1 // Copyright 2005 Ben Hutchings <ben@decadentplace.org.uk>.
   2 // See the file "COPYING" for licence details.
   3
   4 #include <cassert>
   5 #include <exception>
   6 #include <fstream>
   7 #include <iomanip>
   8 #include <iostream>
   9 #include <memory>
  10 #include <queue>
  11 #include <set>
  12 #include <sstream>
  13 #include <string>
  14
  15 #include <stdlib.h>
  16 #include <unistd.h>
  17
  18 #include <boost/shared_ptr.hpp>
  19
  20 #include <gdkmm/pixbuf.h>
  21 #include <glibmm/convert.h>
  22 #include <glibmm/spawn.h>
  23 #include <gtkmm/main.h>
  24 #include <gtkmm/window.h>
  25
  26 #include <imglib2/ImageErrors.h>
  27 #include <nsGUIEvent.h>
  28 #include <nsIBoxObject.h>
  29 #include <nsIContent.h>
  30 #include <nsIDocShell.h>
  31 #include <nsIDOMAbstractView.h>
  32 #include <nsIDOMDocumentEvent.h>
  33 #include <nsIDOMDocumentView.h>
  34 #include <nsIDOMElement.h>
  35 #include <nsIDOMEventTarget.h>
  36 #include <nsIDOMHTMLDocument.h>
  37 #include <nsIDOMMouseEvent.h>
  38 #include <nsIDOMNSDocument.h>
  39 #include <nsIDOMWindow.h>
  40 #include <nsIEventStateManager.h>
  41 #include <nsIInterfaceRequestorUtils.h>
  42 #include <nsIURI.h> // required before nsILink.h
  43 #include <nsILink.h>
  44 #include <nsIPresContext.h>
  45 #include <nsIPresShell.h>
  46 #include <nsIWebBrowser.h>
  47 #include <nsString.h>
  48
  49 #include "browserwidget.hpp"
  50 #include "childiterator.hpp"
  51 #include "dvd.hpp"
  52 #include "framebuffer.hpp"
  53 #include "linkiterator.hpp"
  54 #include "pixbufs.hpp"
  55 #include "stylesheets.hpp"
  56 #include "temp_file.hpp"
  57 #include "video.hpp"
  58 #include "xpcom_support.hpp"
  59
  60 using xpcom_support::check;
  61
  62 namespace
  63 {
  64     struct rectangle
  65     {
  66         int left, top;     // inclusive
  67         int right, bottom; // exclusive
  68
  69         rectangle operator|=(const rectangle & other)
  70             {
  71                 if (other.empty())
  72                 {
  73                     // use current extents unchanged
  74                 }
  75                 else if (empty())
  76                 {
  77                     // use other extents
  78                     *this = other;
  79                 }
  80                 else
  81                 {
  82                     // find rectangle enclosing both extents
  83                     left = std::min(left, other.left);
  84                     top = std::min(top, other.top);
  85                     right = std::max(right, other.right);
  86                     bottom = std::max(bottom, other.bottom);
  87                 }
  88
  89                 return *this;
  90             }
  91
  92         rectangle operator&=(const rectangle & other)
  93             {
  94                 // find rectangle enclosed in both extents
  95                 left = std::max(left, other.left);
  96                 top = std::max(top, other.top);
  97                 right = std::max(left, std::min(right, other.right));
  98                 bottom = std::max(top, std::min(bottom, other.bottom));
  99                 return *this;
 100             }
 101
 102         bool empty() const
 103             {
 104                 return left == right || bottom == top;
 105             }
 106     };
 107
 108     rectangle get_elem_rect(nsIDOMNSDocument * ns_doc,
 109                             nsIDOMElement * elem)
 110     {
 111         rectangle result;
 112
 113         nsCOMPtr<nsIBoxObject> box;
 114         check(ns_doc->GetBoxObjectFor(elem, getter_AddRefs(box)));
 115         int width, height;
 116         check(box->GetScreenX(&result.left));
 117         check(box->GetScreenY(&result.top));
 118         check(box->GetWidth(&width));
 119         check(box->GetHeight(&height));
 120         result.right = result.left + width;
 121         result.bottom = result.top + height;
 122
 123         for (ChildIterator it = ChildIterator(elem), end; it != end; ++it)
 124         {
 125             nsCOMPtr<nsIDOMNode> child_node(*it);
 126             PRUint16 child_type;
 127             if (check(child_node->GetNodeType(&child_type)),
 128                 child_type == nsIDOMNode::ELEMENT_NODE)
 129             {
 130                 nsCOMPtr<nsIDOMElement> child_elem(
 131                     do_QueryInterface(child_node));
 132                 result |= get_elem_rect(ns_doc, child_elem);
 133             }
 134         }
 135
 136         return result;
 137     }
 138
 139     class WebDvdWindow : public Gtk::Window
 140     {
 141     public:
 142         WebDvdWindow(
 143             const video::frame_params & frame_params,
 144             const std::string & main_page_uri,
 145             const std::string & output_dir);
 146
 147     private:
 148         void add_page(const std::string & uri);
 149         void add_video(const std::string & uri);
 150         void load_next_page();
 151         void on_net_state_change(const char * uri, gint flags, guint status);
 152         void save_screenshot();
 153         void process_links(nsIPresShell * pres_shell,
 154                            nsIPresContext * pres_context,
 155                            nsIDOMWindow * dom_window);
 156         void generate_dvd();
 157
 158         enum ResourceType { page_resource, video_resource };
 159         typedef std::pair<ResourceType, int> ResourceEntry;
 160         video::frame_params frame_params_;
 161         std::string output_dir_;
 162         BrowserWidget browser_widget_;
 163         nsCOMPtr<nsIStyleSheet> stylesheet_;
 164         std::queue<std::string> page_queue_;
 165         std::map<std::string, ResourceEntry> resource_map_;
 166         std::vector<std::vector<std::string> > page_links_;
 167         std::vector<std::string> video_paths_;
 168         bool loading_;
 169         int pending_req_count_;
 170         std::auto_ptr<temp_file> background_temp_;
 171         struct link_state;
 172         std::auto_ptr<link_state> link_state_;
 173         std::vector<boost::shared_ptr<temp_file> > page_temp_files_;
 174     };
 175
 176     WebDvdWindow::WebDvdWindow(
 177         const video::frame_params & frame_params,
 178         const std::string & main_page_uri,
 179         const std::string & output_dir)
 180             : frame_params_(frame_params),
 181               output_dir_(output_dir),
 182               stylesheet_(load_css("file://" WEBDVD_LIB_DIR "/webdvd.css")),
 183               loading_(false),
 184               pending_req_count_(0)
 185     {
 186         set_default_size(frame_params_.width, frame_params_.height);
 187         add(browser_widget_);
 188         browser_widget_.show();
 189         browser_widget_.signal_net_state().connect(
 190             SigC::slot(*this, &WebDvdWindow::on_net_state_change));
 191
 192         add_page(main_page_uri);
 193         load_next_page();
 194     }
 195
 196     void WebDvdWindow::add_page(const std::string & uri)
 197     {
 198         if (resource_map_.insert(
 199                 std::make_pair(uri, ResourceEntry(page_resource, 0)))
 200             .second)
 201         {
 202             page_queue_.push(uri);
 203         }
 204     }
 205
 206     void WebDvdWindow::add_video(const std::string & uri)
 207     {
 208         if (resource_map_.insert(
 209                 std::make_pair(uri, ResourceEntry(video_resource,
 210                                                   video_paths_.size() + 1)))
 211             .second)
 212         {
 213             // FIXME: Should accept some slightly different URI prefixes
 214             // (e.g. file://localhost/) and decode any URI-escaped
 215             // characters in the path.
 216             assert(uri.compare(0, 8, "file:///") == 0);
 217             video_paths_.push_back(uri.substr(7));
 218         }
 219     }
 220
 221     void WebDvdWindow::load_next_page()
 222     {
 223         loading_ = true;
 224
 225         assert(!page_queue_.empty());
 226         const std::string & uri = page_queue_.front();
 227         std::cout << "loading " << uri << std::endl;
 228
 229         std::size_t page_count = page_links_.size();
 230         resource_map_[uri].second = ++page_count;
 231         page_links_.resize(page_count);
 232         browser_widget_.load_uri(uri);
 233     }
 234
 235     void WebDvdWindow::on_net_state_change(const char * uri,
 236                                            gint flags, guint status)
 237     {
 238         enum {
 239             process_nothing,
 240             process_new_page,
 241             process_current_link
 242         } action = process_nothing;
 243
 244         if (flags & GTK_MOZ_EMBED_FLAG_IS_REQUEST)
 245         {
 246             if (flags & GTK_MOZ_EMBED_FLAG_START)
 247                 ++pending_req_count_;
 248             if (flags & GTK_MOZ_EMBED_FLAG_STOP)
 249             {
 250                 assert(pending_req_count_ != 0);
 251                 --pending_req_count_;
 252             }
 253             if (pending_req_count_ == 0 && link_state_.get())
 254                 action = process_current_link;
 255         }
 256
 257         if (flags & GTK_MOZ_EMBED_FLAG_STOP
 258             && flags & GTK_MOZ_EMBED_FLAG_IS_WINDOW)
 259             action = process_new_page;
 260
 261         if (action != process_nothing)
 262         {
 263             assert(loading_ && !page_queue_.empty());
 264             assert(pending_req_count_ == 0);
 265
 266             try
 267             {
 268                 // Check whether the load was successful, ignoring this
 269                 // pseudo-error.
 270                 if (status != NS_IMAGELIB_ERROR_LOAD_ABORTED)
 271                     check(status);
 272
 273                 nsCOMPtr<nsIWebBrowser> browser(
 274                     browser_widget_.get_browser());
 275                 nsCOMPtr<nsIDocShell> doc_shell(do_GetInterface(browser));
 276                 assert(doc_shell);
 277                 nsCOMPtr<nsIPresShell> pres_shell;
 278                 check(doc_shell->GetPresShell(getter_AddRefs(pres_shell)));
 279                 nsCOMPtr<nsIPresContext> pres_context;
 280                 check(doc_shell->GetPresContext(
 281                           getter_AddRefs(pres_context)));
 282                 nsCOMPtr<nsIDOMWindow> dom_window;
 283                 check(browser->GetContentDOMWindow(
 284                           getter_AddRefs(dom_window)));
 285
 286                 if (action == process_new_page)
 287                 {
 288                     apply_style_sheet(stylesheet_, pres_shell);
 289                     save_screenshot();
 290                 }
 291                 process_links(pres_shell, pres_context, dom_window);
 292                 if (!link_state_.get())
 293                 {
 294                     page_queue_.pop();
 295                     if (page_queue_.empty())
 296                     {
 297                         generate_dvd();
 298                         Gtk::Main::quit();
 299                     }
 300                     else
 301                         load_next_page();
 302                 }
 303             }
 304             catch (std::exception & e)
 305             {
 306                 std::cerr << "Fatal error";
 307                 if (!page_queue_.empty())
 308                     std::cerr << " while processing <" << page_queue_.front()
 309                               << ">";
 310                 std::cerr << ": " << e.what() << "\n";
 311                 Gtk::Main::quit();
 312             }
 313         }
 314     }
 315
 316     void WebDvdWindow::save_screenshot()
 317     {
 318         Glib::RefPtr<Gdk::Window> window(get_window());
 319         assert(window);
 320         window->process_updates(true);
 321
 322         background_temp_.reset(new temp_file("webdvd-back-"));
 323         background_temp_->close();
 324         std::cout << "saving " << background_temp_->get_name() << std::endl;
 325         Gdk::Pixbuf::create(Glib::RefPtr<Gdk::Drawable>(window),
 326                             window->get_colormap(),
 327                             0, 0, 0, 0,
 328                             frame_params_.width, frame_params_.height)
 329             ->save(background_temp_->get_name(), "png");
 330     }
 331
 332     struct WebDvdWindow::link_state
 333     {
 334         Glib::RefPtr<Gdk::Pixbuf> diff_pixbuf;
 335
 336         std::auto_ptr<temp_file> spumux_temp;
 337         std::ofstream spumux_file;
 338
 339         std::auto_ptr<temp_file> links_temp;
 340
 341         int link_num;
 342         LinkIterator links_it, links_end;
 343
 344         rectangle link_rect;
 345         bool link_changing;
 346         Glib::RefPtr<Gdk::Pixbuf> norm_pixbuf;
 347     };
 348
 349     void WebDvdWindow::process_links(nsIPresShell * pres_shell,
 350                                      nsIPresContext * pres_context,
 351                                      nsIDOMWindow * dom_window)
 352     {
 353         Glib::RefPtr<Gdk::Window> window(get_window());
 354         assert(window);
 355
 356         nsCOMPtr<nsIDOMDocument> basic_doc;
 357         check(dom_window->GetDocument(getter_AddRefs(basic_doc)));
 358         nsCOMPtr<nsIDOMNSDocument> ns_doc(do_QueryInterface(basic_doc));
 359         assert(ns_doc);
 360         nsCOMPtr<nsIEventStateManager> event_state_man(
 361             pres_context->EventStateManager()); // does not AddRef
 362         assert(event_state_man);
 363         nsCOMPtr<nsIDOMDocumentEvent> event_factory(
 364             do_QueryInterface(basic_doc));
 365         assert(event_factory);
 366         nsCOMPtr<nsIDOMDocumentView> doc_view(do_QueryInterface(basic_doc));
 367         assert(doc_view);
 368         nsCOMPtr<nsIDOMAbstractView> view;
 369         check(doc_view->GetDefaultView(getter_AddRefs(view)));
 370
 371         // Set up or recover our iteration state.
 372         std::auto_ptr<link_state> state(link_state_);
 373         if (!state.get())
 374         {
 375             state.reset(new link_state);
 376
 377             state->diff_pixbuf = Gdk::Pixbuf::create(
 378                 Gdk::COLORSPACE_RGB,
 379                 true, 8, // has_alpha, bits_per_sample
 380                 frame_params_.width, frame_params_.height);
 381
 382             state->spumux_temp.reset(new temp_file("webdvd-spumux-"));
 383             state->spumux_temp->close();
 384
 385             state->links_temp.reset(new temp_file("webdvd-links-"));
 386             state->links_temp->close();
 387
 388             state->spumux_file.open(state->spumux_temp->get_name().c_str());
 389             state->spumux_file <<
 390                 "<subpictures>\n"
 391                 "  <stream>\n"
 392                 "    <spu force='yes' start='00:00:00.00'\n"
 393                 "        highlight='" << state->links_temp->get_name()
 394                                << "'\n"
 395                 "        select='" << state->links_temp->get_name()
 396                                << "'>\n";
 397
 398             state->link_num = 0;
 399             state->links_it = LinkIterator(basic_doc);
 400             state->link_changing = false;
 401         }
 402
 403         rectangle window_rect = {
 404             0, 0, frame_params_.width, frame_params_.height
 405         };
 406
 407         for (/* no initialisation */;
 408              state->links_it != state->links_end;
 409              ++state->links_it)
 410         {
 411             nsCOMPtr<nsIDOMNode> node(*state->links_it);
 412
 413             // Find the link URI.
 414             nsCOMPtr<nsILink> link(do_QueryInterface(node));
 415             assert(link);
 416             nsCOMPtr<nsIURI> uri;
 417             check(link->GetHrefURI(getter_AddRefs(uri)));
 418             std::string uri_string;
 419             {
 420                 nsCString uri_ns_string;
 421                 check(uri->GetSpec(uri_ns_string));
 422                 uri_string.assign(uri_ns_string.BeginReading(),
 423                                   uri_ns_string.EndReading());
 424             }
 425             std::string uri_sans_fragment(uri_string, 0, uri_string.find('#'));
 426
 427             // Is this a new link?
 428             if (!state->link_changing)
 429             {
 430                 // Find a rectangle enclosing the link and clip it to the
 431                 // window.
 432                 nsCOMPtr<nsIDOMElement> elem(do_QueryInterface(node));
 433                 assert(elem);
 434                 state->link_rect = get_elem_rect(ns_doc, elem);
 435                 state->link_rect &= window_rect;
 436
 437                 if (state->link_rect.empty())
 438                 {
 439                     std::cerr << "Ignoring invisible link to "
 440                               << uri_string << "\n";
 441                     continue;
 442                 }
 443
 444                 ++state->link_num;
 445
 446                 if (state->link_num >= dvd::menu_buttons_max)
 447                 {
 448                     if (state->link_num == dvd::menu_buttons_max)
 449                         std::cerr << "No more than " << dvd::menu_buttons_max
 450                                   << " buttons can be placed on a page\n";
 451                     std::cerr << "Ignoring link to " << uri_string << "\n";
 452                     continue;
 453                 }
 454
 455                 // Check whether this is a link to a video or a page then
 456                 // add it to the known resources if not already seen.
 457                 nsCString path;
 458                 check(uri->GetPath(path));
 459                 // FIXME: This is a bit of a hack.  Perhaps we could decide
 460                 // later based on the MIME type determined by Mozilla?
 461                 if (path.Length() > 4
 462                     && std::strcmp(path.EndReading() - 4, ".vob") == 0)
 463                 {
 464                     PRBool is_file;
 465                     check(uri->SchemeIs("file", &is_file));
 466                     if (!is_file)
 467                     {
 468                         std::cerr << "Links to video must use the file:"
 469                                   << " scheme\n";
 470                         continue;
 471                     }
 472                     add_video(uri_sans_fragment);
 473                 }
 474                 else
 475                 {
 476                     add_page(uri_sans_fragment);
 477                 }
 478
 479                 nsCOMPtr<nsIContent> content(do_QueryInterface(node));
 480                 assert(content);
 481                 nsCOMPtr<nsIDOMEventTarget> event_target(
 482                     do_QueryInterface(node));
 483                 assert(event_target);
 484
 485                 state->norm_pixbuf = Gdk::Pixbuf::create(
 486                     Glib::RefPtr<Gdk::Drawable>(window),
 487                     window->get_colormap(),
 488                     state->link_rect.left,
 489                     state->link_rect.top,
 490                     0,
 491                     0,
 492                     state->link_rect.right - state->link_rect.left,
 493                     state->link_rect.bottom - state->link_rect.top);
 494
 495                 nsCOMPtr<nsIDOMEvent> event;
 496                 check(event_factory->CreateEvent(
 497                           NS_ConvertASCIItoUTF16("MouseEvents"),
 498                           getter_AddRefs(event)));
 499                 nsCOMPtr<nsIDOMMouseEvent> mouse_event(
 500                     do_QueryInterface(event));
 501                 assert(mouse_event);
 502                 check(mouse_event->InitMouseEvent(
 503                           NS_ConvertASCIItoUTF16("mouseover"),
 504                           true,  // can bubble
 505                           true,  // cancelable
 506                           view,
 507                           0,     // detail: mouse click count
 508                           state->link_rect.left, // screenX
 509                           state->link_rect.top,  // screenY
 510                           state->link_rect.left, // clientX
 511                           state->link_rect.top,  // clientY
 512                           false, false, false, false, // qualifiers
 513                           0,     // button: left (or primary)
 514                           0));   // related target
 515                 PRBool dummy;
 516                 check(event_target->DispatchEvent(mouse_event,
 517                                                   &dummy));
 518                 check(event_state_man->SetContentState(content,
 519                                                        NS_EVENT_STATE_HOVER));
 520
 521                 pres_shell->FlushPendingNotifications(true);
 522
 523                 // We may have to exit and wait for image loading
 524                 // to complete, at which point we will be called
 525                 // again.
 526                 if (pending_req_count_ > 0)
 527                 {
 528                     state->link_changing = true;
 529                     link_state_ = state;
 530                     return;
 531                 }
 532             }
 533
 534             window->process_updates(true);
 535
 536             Glib::RefPtr<Gdk::Pixbuf> changed_pixbuf(
 537                 Gdk::Pixbuf::create(
 538                     Glib::RefPtr<Gdk::Drawable>(window),
 539                     window->get_colormap(),
 540                     state->link_rect.left,
 541                     state->link_rect.top,
 542                     0,
 543                     0,
 544                     state->link_rect.right - state->link_rect.left,
 545                     state->link_rect.bottom - state->link_rect.top));
 546             diff_rgb_pixbufs(
 547                 state->norm_pixbuf,
 548                 changed_pixbuf,
 549                 state->diff_pixbuf,
 550                 state->link_rect.left,
 551                 state->link_rect.top,
 552                 state->link_rect.right - state->link_rect.left,
 553                 state->link_rect.bottom - state->link_rect.top);
 554
 555             state->spumux_file <<
 556                 "      <button x0='" << state->link_rect.left << "'"
 557                 " y0='" << state->link_rect.top << "'"
 558                 " x1='" << state->link_rect.right - 1 << "'"
 559                 " y1='" << state->link_rect.bottom - 1 << "'/>\n";
 560
 561             // Add to the page's links, ignoring any fragment (for now).
 562             page_links_.back().push_back(uri_sans_fragment);
 563         }
 564
 565         quantise_rgba_pixbuf(state->diff_pixbuf, dvd::button_n_colours);
 566
 567         std::cout << "saving " << state->links_temp->get_name()
 568                   << std::endl;
 569         state->diff_pixbuf->save(state->links_temp->get_name(), "png");
 570
 571         state->spumux_file <<
 572             "    </spu>\n"
 573             "  </stream>\n"
 574             "</subpictures>\n";
 575
 576         state->spumux_file.close();
 577
 578         // TODO: if (!state->spumux_file) throw ...
 579
 580         {
 581             boost::shared_ptr<temp_file> vob_temp(
 582                 new temp_file("webdvd-vob-"));
 583             std::ostringstream command_stream;
 584             command_stream << "pngtopnm "
 585                            << background_temp_->get_name()
 586                            << " | ppmtoy4m -v0 -n1 -F"
 587                            << frame_params_.rate_numer
 588                            << ":" << frame_params_.rate_denom
 589                            << " -A" << frame_params_.pixel_ratio_width
 590                            << ":" << frame_params_.pixel_ratio_height
 591                            << (" -Ip -S420_mpeg2"
 592                                " | mpeg2enc -v0 -f8 -a2 -o/dev/stdout"
 593                                " | mplex -v0 -f8 -o/dev/stdout /dev/stdin"
 594                                " | spumux -v0 -mdvd ")
 595                            << state->spumux_temp->get_name()
 596                            << " > " << vob_temp->get_name();
 597             std::string command(command_stream.str());
 598             const char * argv[] = {
 599                 "/bin/sh", "-c", command.c_str(), 0
 600             };
 601             std::cout << "running " << argv[2] << std::endl;
 602             int command_result;
 603             Glib::spawn_sync(".",
 604                              Glib::ArrayHandle<std::string>(
 605                                  argv, sizeof(argv)/sizeof(argv[0]),
 606                                  Glib::OWNERSHIP_NONE),
 607                              Glib::SPAWN_STDOUT_TO_DEV_NULL,
 608                              SigC::Slot0<void>(),
 609                              0, 0,
 610                              &command_result);
 611             if (command_result != 0)
 612                 throw std::runtime_error("spumux pipeline failed");
 613
 614             page_temp_files_.push_back(vob_temp);
 615         }
 616     }
 617
 618     void generate_page_dispatch(std::ostream &, int indent,
 619                                 int first_page, int last_page);
 620
 621     void WebDvdWindow::generate_dvd()
 622     {
 623         temp_file temp("webdvd-dvdauthor-");
 624         temp.close();
 625         std::ofstream file(temp.get_name().c_str());
 626
 627         // We generate code that uses registers in the following way:
 628         //
 629         // g0:     link destination (when jumping to menu 1), then scratch
 630         // g1:     current location
 631         // g2-g11: location history (g2 = most recent)
 632         // g12:    location that last linked to a video
 633         //
 634         // All locations are divided into two bitfields: the least
 635         // significant 10 bits are a page/menu number and the most
 636         // significant 6 bits are a link/button number.  This is
 637         // chosen for compatibility with the encoding of the s8
 638         // (button) register.
 639         //
 640         static const int link_mult = dvd::reg_s8_button_mult;
 641         static const int page_mask = link_mult - 1;
 642         static const int link_mask = (1 << dvd::reg_bits) - link_mult;
 643
 644         file <<
 645             "<dvdauthor>\n"
 646             "  <vmgm>\n"
 647             "    <menus>\n";
 648
 649         for (std::size_t page_num = 1;
 650              page_num <= page_links_.size();
 651              ++page_num)
 652         {
 653             std::vector<std::string> & page_links =
 654                 page_links_[page_num - 1];
 655
 656             if (page_num == 1)
 657             {
 658                 // This is the first page (root menu) which needs to
 659                 // include initialisation and dispatch code.
 660
 661                 file <<
 662                     "      <pgc entry='title'>\n"
 663                     "        <pre>\n"
 664                     // Has the location been set yet?
 665                     "          if (g1 eq 0)\n"
 666                     "          {\n"
 667                     // Initialise the current location to first link on
 668                     // this page.
 669                     "            g1 = " << 1 * link_mult + 1 << ";\n"
 670                     "          }\n"
 671                     "          else\n"
 672                     "          {\n"
 673                     // Has the user selected a link?
 674                     "            if (g0 ne 0)\n"
 675                     "            {\n"
 676                     // First update the history.
 677                     // Does link go to the last page in the history?
 678                     "              if (((g0 ^ g2) &amp; " << page_mask
 679                      << ") == 0)\n"
 680                     // It does; we treat this as going back and pop the old
 681                     // location off the history stack into the current
 682                     // location.  Clear the free stack slot.
 683                     "              {\n"
 684                     "                g1 = g2; g2 = g3; g3 = g4; g4 = g5;\n"
 685                     "                g5 = g6; g6 = g7; g7 = g8; g8 = g9;\n"
 686                     "                g9 = g10; g10 = g11; g11 = 0;\n"
 687                     "              }\n"
 688                     "              else\n"
 689                     // Link goes to some other page, so push current
 690                     // location onto the history stack and set the current
 691                     // location to be exactly the target location.
 692                     "              {\n"
 693                     "                g11 = g10; g10 = g9; g9 = g8; g8 = g7;\n"
 694                     "                g7 = g6; g6 = g5; g5 = g4; g4 = g3;\n"
 695                     "                g3 = g2; g2 = g1; g1 = g0;\n"
 696                     "              }\n"
 697                     "            }\n"
 698                     // Find the target page number.
 699                     "            g0 = g1 &amp; " << page_mask << ";\n";
 700                 // There seems to be no way to perform a computed jump,
 701                 // so we generate all possible jumps and a binary search
 702                 // to select the correct one.
 703                 generate_page_dispatch(file, 12, 1, page_links_.size());
 704                 file <<
 705                     "          }\n";
 706             }
 707             else // page_num != 1
 708             {
 709                 file <<
 710                     "      <pgc>\n"
 711                     "        <pre>\n";
 712             }
 713
 714             file <<
 715                 // Clear link indicator and highlight the
 716                 // appropriate link/button.
 717                 "          g0 = 0; s8 = g1 &amp; " << link_mask << ";\n"
 718                 "        </pre>\n"
 719                 "        <vob file='"
 720                  << page_temp_files_[page_num - 1]->get_name() << "'/>\n";
 721
 722             for (std::size_t link_num = 1;
 723                  link_num <= page_links.size();
 724                  ++link_num)
 725             {
 726                 file <<
 727                     "        <button>"
 728                     // Update current location.
 729                     " g1 = " << link_num * link_mult + page_num << ";";
 730
 731                 // Jump to appropriate resource.
 732                 const ResourceEntry & resource_loc =
 733                     resource_map_[page_links[link_num - 1]];
 734                 if (resource_loc.first == page_resource)
 735                     file <<
 736                         " g0 = " << 1 * link_mult + resource_loc.second << ";"
 737                         " jump menu 1;";
 738                 else if (resource_loc.first == video_resource)
 739                     file << " jump title " << resource_loc.second << ";";
 740
 741                 file <<  " </button>\n";
 742             }
 743
 744             file << "      </pgc>\n";
 745         }
 746
 747         file <<
 748             "    </menus>\n"
 749             "  </vmgm>\n";
 750
 751         // Generate a titleset for each video.  This appears to make
 752         // jumping to titles a whole lot simpler.
 753         for (std::size_t video_num = 1;
 754              video_num <= video_paths_.size();
 755              ++video_num)
 756         {
 757             file <<
 758                 "  <titleset>\n"
 759                 // Generate a dummy menu so that the menu button on the
 760                 // remote control will work.
 761                 "    <menus>\n"
 762                 "      <pgc entry='root'>\n"
 763                 "        <pre> jump vmgm menu; </pre>\n"
 764                 "      </pgc>\n"
 765                 "    </menus>\n"
 766                 "    <titles>\n"
 767                 "      <pgc>\n"
 768                 // Record calling page/menu.
 769                 "        <pre> g12 = g1; </pre>\n"
 770                 // FIXME: Should XML-escape the path
 771                 "        <vob file='" << video_paths_[video_num - 1]
 772                  << "'/>\n"
 773                 // If page/menu location has not been changed during the
 774                 // video, change the location to be the following
 775                 // link/button when returning to it.  In any case,
 776                 // return to a page/menu.
 777                 "        <post> if (g1 eq g12) g1 = g1 + " << link_mult
 778                  << "; call menu; </post>\n"
 779                 "      </pgc>\n"
 780                 "    </titles>\n"
 781                 "  </titleset>\n";
 782         }
 783
 784         file <<
 785             "</dvdauthor>\n";
 786
 787         file.close();
 788
 789         {
 790             const char * argv[] = {
 791                 "dvdauthor",
 792                 "-o", output_dir_.c_str(),
 793                 "-x", temp.get_name().c_str(),
 794                 0
 795             };
 796             int command_result;
 797             Glib::spawn_sync(".",
 798                              Glib::ArrayHandle<std::string>(
 799                                  argv, sizeof(argv)/sizeof(argv[0]),
 800                                  Glib::OWNERSHIP_NONE),
 801                              Glib::SPAWN_SEARCH_PATH
 802                              | Glib::SPAWN_STDOUT_TO_DEV_NULL,
 803                              SigC::Slot0<void>(),
 804                              0, 0,
 805                              &command_result);
 806             if (command_result != 0)
 807                 throw std::runtime_error("dvdauthor failed");
 808         }
 809     }
 810
 811     void generate_page_dispatch(std::ostream & file, int indent,
 812                                 int first_page, int last_page)
 813     {
 814         if (first_page == 1 && last_page == 1)
 815         {
 816             // The dispatch code is *on* page 1 so we must not dispatch to
 817             // page 1 since that would cause an infinite loop.  This case
 818             // should be unreachable if there is more than one page due
 819             // to the following case.
 820         }
 821         else if (first_page == 1 && last_page == 2)
 822         {
 823             // dvdauthor doesn't allow empty blocks or null statements so
 824             // when selecting between pages 1 and 2 we don't use an "else"
 825             // part.  We must use braces so that a following "else" will
 826             // match the right "if".
 827             file << std::setw(indent) << "" << "{\n"
 828                  << std::setw(indent) << "" << "if (g0 eq 2)\n"
 829                  << std::setw(indent + 2) << "" << "jump menu 2;\n"
 830                  << std::setw(indent) << "" << "}\n";
 831         }
 832         else if (first_page == last_page)
 833         {
 834             file << std::setw(indent) << ""
 835                  << "jump menu " << first_page << ";\n";
 836         }
 837         else
 838         {
 839             int middle = (first_page + last_page) / 2;
 840             file << std::setw(indent) << "" << "if (g0 le " << middle << ")\n";
 841             generate_page_dispatch(file, indent + 2, first_page, middle);
 842             file << std::setw(indent) << "" << "else\n";
 843             generate_page_dispatch(file, indent + 2, middle + 1, last_page);
 844         }
 845     }
 846
 847     const video::frame_params & lookup_frame_params(const char * str)
 848     {
 849         assert(str);
 850         static const struct { const char * str; bool is_ntsc; }
 851         known_strings[] = {
 852             { "NTSC",  true },
 853             { "ntsc",  true },
 854             { "PAL",   false },
 855             { "pal",   false },
 856             // For DVD purposes, SECAM can be treated identically to PAL.
 857             { "SECAM", false },
 858             { "secam", false }
 859         };
 860         for (std::size_t i = 0;
 861              i != sizeof(known_strings)/sizeof(known_strings[0]);
 862              ++i)
 863             if (std::strcmp(str, known_strings[i].str) == 0)
 864                 return known_strings[i].is_ntsc ?
 865                     video::ntsc_params : video::pal_params;
 866         throw std::runtime_error(
 867             std::string("Invalid video standard: ").append(str));
 868     }
 869
 870     void print_usage(std::ostream & stream, const char * command_name)
 871     {
 872         stream << "Usage: " << command_name
 873                << (" [gtk-options] [--video-std std-name]"
 874                    " front-page-url output-dir\n");
 875     }
 876
 877 } // namespace
 878
 879 int main(int argc, char ** argv)
 880 {
 881     try
 882     {
 883         // Do initial argument parsing.  We have to do this before
 884         // letting Gtk parse the arguments since we need to spawn Xvfb
 885         // first and that's currently dependent on the frame
 886         // parameters (though we could just make it large enough for
 887         // any frame) and also an unnecessary expense in some cases.
 888         video::frame_params frame_params = video::pal_params;
 889         for (int argi = 1; argi != argc; ++argi)
 890         {
 891             if (std::strcmp(argv[argi], "--") == 0)
 892                 break;
 893             if (std::strcmp(argv[argi], "--help") == 0)
 894             {
 895                 print_usage(std::cout, argv[0]);
 896                 return EXIT_SUCCESS;
 897             }
 898             if (std::strcmp(argv[argi], "--video-std") == 0)
 899             {
 900                 if (argi + 1 == argc)
 901                 {
 902                     std::cerr << "Missing argument to --video-std\n";
 903                     print_usage(std::cerr, argv[0]);
 904                     return EXIT_FAILURE;
 905                 }
 906                 frame_params = lookup_frame_params(argv[argi + 1]);
 907                 break;
 908             }
 909         }
 910
 911         // Spawn Xvfb and set env variables so that Xlib will use it
 912         // Use 8 bits each for RGB components, which should translate into
 913         // "enough" bits for YUV components.
 914         FrameBuffer fb(frame_params.width, frame_params.height, 3 * 8);
 915         setenv("XAUTHORITY", fb.get_x_authority().c_str(), true);
 916         setenv("DISPLAY", fb.get_x_display().c_str(), true);
 917
 918         // Initialise Gtk
 919         Gtk::Main kit(argc, argv);
 920
 921         // Complete argument parsing with Gtk's options out of the way.
 922         int argi = 1;
 923         while (argi != argc)
 924         {
 925             if (std::strcmp(argv[argi], "--video-std") == 0)
 926             {
 927                 argi += 2;
 928             }
 929             else if (std::strcmp(argv[argi], "--") == 0)
 930             {
 931                 argi += 1;
 932                 break;
 933             }
 934             else if (argv[argi][0] == '-')
 935             {
 936                 std::cerr << "Invalid option: " << argv[argi] << "\n";
 937                 print_usage(std::cerr, argv[0]);
 938                 return EXIT_FAILURE;
 939             }
 940             else
 941                 break;
 942         }
 943         if (argi != argc - 2)
 944         {
 945             print_usage(std::cerr, argv[0]);
 946             return EXIT_FAILURE;
 947         }
 948
 949         // Initialise Mozilla
 950         BrowserWidget::init();
 951
 952         WebDvdWindow window(frame_params, argv[argi], argv[argi + 1]);
 953         Gtk::Main::run(window);
 954     }
 955     catch (std::exception & e)
 956     {
 957         std::cerr << "Fatal error: " << e.what() << "\n";
 958         return EXIT_FAILURE;
 959     }
 960
 961     return EXIT_SUCCESS;
 962 }