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