Display an error if the user tries to save chapters that contain editions without a single chapter entry. Allow saving empty chapters to a Matroska file by removing all chapters contained in the file.

Fixes for bug 422.

ChangeLog

@@ -1,3 +1,11 @@
+2009-07-06  Moritz Bunkus  <moritz@bunkus.org>
+
+	* mmg: bug fix: Trying to save chapters that contain editions
+	without a single chapter entry does no longer result in a crash
+	but a descriptive error message instead. Saving empty chapters to
+	a Matroska file will remove all chapters contained in the file
+	instead of not doing anything. Fixes for bug 422.
+
 2009-07-05  Moritz Bunkus  <moritz@bunkus.org>
 
 	* mkvinfo: enhancement: Implemented speed-ups of up to 50% for

src/common/kax_analyzer.cpp

@@ -310,6 +310,23 @@ kax_analyzer_c::update_element(EbmlElement *e,
   return uer_success;
 }
 
+kax_analyzer_c::update_element_result_e
+kax_analyzer_c::remove_elements(EbmlId id) {
+  try {
+    call_and_validate({},                          "remove_elements_0");
+    call_and_validate(overwrite_all_instances(id), "remove_elements_1");
+    call_and_validate(merge_void_elements(),       "remove_elements_2");
+    call_and_validate(remove_from_meta_seeks(id),  "remove_elements_3");
+    call_and_validate(merge_void_elements(),       "remove_elements_4");
+
+  } catch (kax_analyzer_c::update_element_result_e result) {
+    debug_dump_elements_maybe("update_element_exception");
+    return result;
+  }
+
+  return uer_success;
+}
+
 /** \brief Sets the m_segment size to the length of the m_file
  */
 void

src/common/kax_analyzer.h

@@ -85,6 +85,7 @@ public:
   virtual ~kax_analyzer_c();
 
   virtual update_element_result_e update_element(EbmlElement *e, bool write_defaults = false);
+  virtual update_element_result_e remove_elements(EbmlId id);
   virtual EbmlMaster *read_all(const EbmlCallbacks &callbacks);
 
   virtual EbmlElement *read_element(kax_analyzer_data_c *element_data);

src/mmg/tabs/chapters.cpp

@@ -600,7 +600,7 @@ tab_chapters::on_save_chapters(wxCommandEvent &evt) {
     return;
 
   if (source_is_kax_file) {
-    display_update_element_result(analyzer->update_element(chapters));
+    write_chapters_to_matroska_file();
     return;
   }
 
@@ -641,7 +641,7 @@ tab_chapters::on_save_chapters_to_kax_file(wxCommandEvent &evt) {
     return;
   }
 
-  display_update_element_result(analyzer->update_element(chapters));
+  write_chapters_to_matroska_file();
   mdlg->set_last_chapters_in_menu(file_name);
 }
 
@@ -776,27 +776,43 @@ tab_chapters::verify_atom_recursively(EbmlElement *e) {
 
 bool
 tab_chapters::verify(bool called_interactively) {
-  KaxEditionEntry *eentry;
   uint32_t eidx, cidx;
 
-  if ((NULL == chapters) || (chapters->ListSize() == 0)) {
-    if (called_interactively)
-      wxMessageBox(Z("No chapter entries have been create yet."), Z("Chapter verification error"), wxCENTER | wxOK | wxICON_ERROR);
+  if (NULL == chapters){
+    wxMessageBox(Z("No chapter entries have been create yet."), Z("Chapter verification error"), wxCENTER | wxOK | wxICON_ERROR);
     return false;
   }
 
+  if (0 == chapters->ListSize())
+    return true;
+
   wxTreeItemId id = tc_chapters->GetSelection();
   if (id.IsOk())
     copy_values(id);
 
+  for (eidx = 0; eidx < chapters->ListSize(); eidx++) {
+    KaxEditionEntry *eentry = static_cast<KaxEditionEntry *>((*chapters)[eidx]);
+    bool contains_atom      = false;
+
+    for (cidx = 0; cidx < eentry->ListSize(); cidx++)
+      if (dynamic_cast<KaxChapterAtom *>((*eentry)[cidx]) != NULL) {
+        contains_atom = true;
+        break;
+      }
+
+    if (!contains_atom) {
+      wxMessageBox(Z("Each edition must contain at least one chapter."), Z("Chapter verification error"), wxCENTER | wxOK | wxICON_ERROR);
+      return false;
+    }
+  }
+
   fix_mandatory_chapter_elements(chapters);
 
   for (eidx = 0; eidx < chapters->ListSize(); eidx++) {
-    eentry = static_cast<KaxEditionEntry *>((*chapters)[eidx]);
-    for (cidx = 0; cidx < eentry->ListSize(); cidx++) {
+    KaxEditionEntry *eentry = static_cast<KaxEditionEntry *>((*chapters)[eidx]);
+    for (cidx = 0; cidx < eentry->ListSize(); cidx++)
       if ((dynamic_cast<KaxChapterAtom *>((*eentry)[cidx]) != NULL) && !verify_atom_recursively((*eentry)[cidx]))
         return false;
-    }
   }
 
   if (!chapters->CheckMandatory())
@@ -1859,7 +1875,9 @@ tab_chapters::is_empty() {
 }
 
 void
-tab_chapters::display_update_element_result(kax_analyzer_c::update_element_result_e result) {
+tab_chapters::write_chapters_to_matroska_file() {
+  kax_analyzer_c::update_element_result_e result = (0 == chapters->ListSize() ? analyzer->remove_elements(KaxChapters::ClassInfos.GlobalId) : analyzer->update_element(chapters));
+
   switch (result) {
     case kax_analyzer_c::uer_success:
       mdlg->set_status_bar(Z("Chapters written."));

src/mmg/tabs/chapters.h

@@ -119,7 +119,7 @@ public:
   bool is_empty();
 
 protected:
-  void display_update_element_result(kax_analyzer_c::update_element_result_e result);
+  void write_chapters_to_matroska_file();
 };
 
 #endif // __TAB_CHAPTERS_H