GUI: attachments: change page storage from list to hash

Each page has an ID when it's stored in the model. This ID used to be
the position in the list. This was fine as long as the list wasn't
dynamic. However, with the new attachment editing features the user can
add and remove attachments in arbitrary order. This means that the
position inside the list changes but not the ID associated with the
page.

Therefore a hash is now used instead with a sequential number as the ID.

src/mkvtoolnix-gui/header_editor/page_model.cpp

@@ -21,10 +21,11 @@ PageBase *
 PageModel::selectedPage(QModelIndex const &idx)
   const {
   auto selectedItem = itemFromIndex(idx.sibling(idx.row(), 0));
-  if (selectedItem)
-    return m_pages[ selectedItem->data(Util::HeaderEditorPageIdRole).value<unsigned int>() ];
+  if (!selectedItem)
+    return {};
 
-  return nullptr;
+  auto pageId = selectedItem->data(Util::HeaderEditorPageIdRole).value<int>();
+  return m_pages.value(pageId, nullptr);
 }
 
 void
@@ -32,43 +33,54 @@ PageModel::appendPage(PageBase *page,
                       QModelIndex const &parentIdx) {
   page->retranslateUi();
 
+  auto pageId     = ++m_pageId;
   auto parentItem = parentIdx.isValid() ? itemFromIndex(parentIdx.sibling(parentIdx.row(), 0)) : invisibleRootItem();
   auto newItems   = QList<QStandardItem *>{};
 
   for (auto idx = columnCount(); idx > 0; --idx)
     newItems << new QStandardItem{};
 
-  newItems[0]->setData(static_cast<unsigned int>(m_pages.count()), Util::HeaderEditorPageIdRole);
+  newItems[0]->setData(pageId, Util::HeaderEditorPageIdRole);
 
   parentItem->appendRow(newItems);
 
   page->m_pageIdx = indexFromItem(newItems[0]);
   page->setItems(newItems);
 
-  m_pages << page;
+  m_pages[pageId] = page;
   if (!parentIdx.isValid())
     m_topLevelPages << page;
 }
 
 bool
 PageModel::deletePage(PageBase *page) {
-  auto idx = m_pages.indexOf(page);
-  if (idx == -1)
+  auto pageId = m_pages.key(page);
+  if (!pageId)
     return false;
 
-  m_pages.removeAt(idx);
+  m_pages.remove(pageId);
   delete page;
 
+  auto idx = m_topLevelPages.indexOf(page);
+  if (-1 != idx)
+    m_topLevelPages.removeAt(idx);
+
   return true;
 }
 
-QList<PageBase *> &
-PageModel::pages() {
-  return m_pages;
+QList<PageBase *>
+PageModel::pages()
+  const {
+  auto pages = QList<PageBase *>{};
+  for (auto const &page : m_pages)
+    pages << page;
+
+  return pages;
 }
 
-QList<PageBase *> &
-PageModel::topLevelPages() {
+QList<PageBase *> const &
+PageModel::topLevelPages()
+  const {
   return m_topLevelPages;
 }
 

src/mkvtoolnix-gui/header_editor/page_model.h

@@ -15,7 +15,9 @@ class PageBase;
 class PageModel: public QStandardItemModel {
   Q_OBJECT;
 protected:
-  QList<PageBase *> m_pages, m_topLevelPages;
+  QHash<int, PageBase *> m_pages;
+  QList<PageBase *> m_topLevelPages;
+  int m_pageId{};
 
 public:
   PageModel(QObject *parent);
@@ -26,8 +28,8 @@ public:
   void appendPage(PageBase *page, QModelIndex const &parentIdx = {});
   bool deletePage(PageBase *page);
 
-  QList<PageBase *> &pages();
-  QList<PageBase *> &topLevelPages();
+  QList<PageBase *> pages() const;
+  QList<PageBase *> const &topLevelPages() const;
 
   void reset();
 

src/mkvtoolnix-gui/header_editor/tab.cpp

@@ -276,8 +276,7 @@ Tab::retranslateUi() {
   m_saveAttachmentContentAction->setIcon(QIcon{Q(":/icons/16x16/document-save.png")});
   m_replaceAttachmentContentAction->setIcon(QIcon{Q(":/icons/16x16/document-open.png")});
 
-  auto &pages = m_model->pages();
-  for (auto const &page : pages)
+  for (auto const &page : m_model->pages())
     page->retranslateUi();
 
   m_model->retranslateUi();
@@ -320,7 +319,7 @@ Tab::title()
 
 bool
 Tab::hasBeenModified() {
-  auto pages = m_model->topLevelPages();
+  auto &pages = m_model->topLevelPages();
   for (auto const &page : pages)
     if (page->hasBeenModified())
       return true;
@@ -330,7 +329,7 @@ Tab::hasBeenModified() {
 
 void
 Tab::doModifications() {
-  auto pages = m_model->topLevelPages();
+  auto &pages = m_model->topLevelPages();
   for (auto const &page : pages)
     page->doModifications();