Undo: isolate undo-commands

This refactors the undo-commands (which are now only "commands").

- Move everything in namespace Command. This allows shortening of
  names without polluting the global namespace. Moreover, the prefix
  Command:: will immediately signal that the undo-machinery is
  invoked. This is more terse than UndoCommands::instance()->...
- Remove the Undo in front of the class-names. Creating an "UndoX"
  object to do "X" is paradoxical.
- Create a base class for all commands that defines the Qt-translation
  functions. Thus all translations end up in the "Command" context.
- Add a workToBeDone() function, which signals whether this should be
  added to the UndoStack. Thus the caller doesn't have to check itself
  whether this any work will be done. Note: Qt5.9 introduces "setObsolete"
  which does the same.
- Split into public and internal header files. In the public header
  file only export the function calls, thus hiding all implementation
  details from the caller.
- Split in different translation units: One for the stubs, one for
  the base classes and one for groups of commands. Currently, there
  is only one class of commands: divelist-commands.
- Move the undoStack from the MainWindow class into commands_base.cpp.
  If we want to implement MDI, this can easily be moved into an
  appropriate Document class.

Signed-off-by: Berthold Stoeger <bstoeger@mail.tuwien.ac.at>

1 files changed, 3 insertions, 1 deletions

diff --git a/desktop-widgets/downloadfromdivecomputer.cpp b/desktop-widgets/downloadfromdivecomputer.cpp
index e63de8f56..de0dd0626 100644
--- a/desktop-widgets/downloadfromdivecomputer.cpp
+++ b/desktop-widgets/downloadfromdivecomputer.cpp
@@ -1,5 +1,6 @@
 // SPDX-License-Identifier: GPL-2.0
 #include "desktop-widgets/downloadfromdivecomputer.h"
+#include "desktop-widgets/command.h"
 #include "core/display.h"
 #include "core/qthelper.h"
 #include "core/settings/qPrefDiveComputer.h"
@@ -508,7 +509,8 @@ void DownloadFromDCWidget::on_ok_clicked()
 		// first new dive) and select it again after processing all the dives
 		int uniqId = downloadTable.dives[downloadTable.nr - 1]->id;
 		process_imported_dives(&downloadTable, preferDownloaded(), true);
-		MainWindow::instance()->undoStack->clear();
+		autogroup_dives();
+		Command::clear();
 		// after process_imported_dives does any merging or resorting needed, we need
 		// to recreate the model for the dive list so we can select the newest dive
 		MainWindow::instance()->recreateDiveList();