Start work on global undo/redo for tweaking

src/calibre/gui2/tweak_book/boss.py

@@ -71,12 +71,27 @@ class Boss(QObject):
         self.current_metadata = self.gui.current_metadata = container.mi
         self.global_undo.open_book(container)
         self.gui.update_window_title()
-        self.gui.file_list.build(container)
+        self.gui.file_list.build(container, preserve_state=False)
+        self.update_global_history_actions()
+
+    def update_global_history_actions(self):
+        gu = self.global_undo
+        for x, text in (('undo', _('&Undo')), ('redo', '&Redo')):
+            ac = getattr(self.gui, 'action_global_%s' % x)
+            ac.setEnabled(getattr(gu, 'can_' + x))
+            ac.setText(text + ' ' + getattr(gu, x + '_msg'))
 
     def add_savepoint(self, msg):
         nc = clone_container(current_container(), self.mkdtemp())
         self.global_undo.add_savepoint(nc, msg)
         set_current_container(nc)
+        self.update_global_history_actions()
+
+    def do_global_undo(self):
+        pass
+
+    def do_global_redo(self):
+        pass
 
     def delete_requested(self, spine_items, other_items):
         if not self.check_dirtied():

src/calibre/gui2/tweak_book/file_list.py

@@ -89,7 +89,25 @@ class FileList(QTreeWidget):
                 'images':'view-image.png',
             }.iteritems()}
 
-    def build(self, container):
+    def get_state(self):
+        s = {'pos':self.verticalScrollBar().value()}
+        s['expanded'] = {c for c, item in self.categories.iteritems() if item.isExpanded()}
+        s['selected'] = {unicode(i.data(0, NAME_ROLE).toString()) for i in self.selectedItems()}
+        return s
+
+    def set_state(self, state):
+        for category, item in self.categories:
+            item.setExpanded(category in state['expanded'])
+        self.verticalScrollBar().setValue(state['pos'])
+        for parent in self.categories.itervalues():
+            for c in (parent.child(i) for i in parent.childCount()):
+                name = unicode(c.data(0, NAME_ROLE).toString())
+                if name in state['selected']:
+                    c.setSelected(True)
+
+    def build(self, container, preserve_state=True):
+        if preserve_state:
+            state = self.get_state()
         self.clear()
         self.root = self.invisibleRootItem()
         self.root.setFlags(Qt.ItemIsDragEnabled)
@@ -221,7 +239,10 @@ class FileList(QTreeWidget):
             processed[name] = create_item(name)
 
         for c in self.categories.itervalues():
-            self.expandItem(c)
+            c.setExpanded(True)
+
+        if preserve_state:
+            self.set_state(state)
 
     def show_context_menu(self, point):
         pass
@@ -277,7 +298,7 @@ class FileListWidget(QWidget):
         for x in ('delete_done',):
             setattr(self, x, getattr(self.file_list, x))
 
-    def build(self, container):
+    def build(self, container, preserve_state=True):
-        self.file_list.build(container)
+        self.file_list.build(container, preserve_state=preserve_state)
 
 

src/calibre/gui2/tweak_book/ui.py

@@ -58,15 +58,26 @@ class Main(MainWindow):
             return ac
 
         self.action_open_book = reg('document_open.png', _('Open &book'), self.boss.open_book, 'open-book', 'Ctrl+O', _('Open a new book'))
+        self.action_global_undo = reg('back.png', _('&Revert to before'), self.boss.do_global_undo, 'global-undo', 'Ctrl+Left',
+                                      _('Revert book to before the last action (Undo)'))
+        self.action_global_redo = reg('forward.png', _('&Revert to after'), self.boss.do_global_redo, 'global-redo', 'Ctrl+Right',
+                                      _('Revert book state to after the next action (Redo)'))
 
     def create_menubar(self):
         b = self.menuBar()
+
         f = b.addMenu(_('&File'))
         f.addAction(self.action_open_book)
 
+        e = b.addMenu(_('&Edit'))
+        e.addAction(self.action_global_undo)
+        e.addAction(self.action_global_redo)
+
     def create_toolbar(self):
         self.global_bar = b = self.addToolBar(_('Global'))
         b.addAction(self.action_open_book)
+        b.addAction(self.action_global_undo)
+        b.addAction(self.action_global_redo)
 
     def create_docks(self):
         self.file_list_dock = d = QDockWidget(_('&Files Browser'), self)

src/calibre/gui2/tweak_book/undo.py

@@ -53,4 +53,23 @@ class GlobalUndoHistory(object):
             self.pos += 1
             return self.current_container
 
+    @property
+    def can_undo(self):
+        return self.pos > 0
+
+    @property
+    def can_redo(self):
+        return self.pos < len(self.states) - 1
+
+    @property
+    def undo_msg(self):
+        if not self.can_undo:
+            return ''
+        return self.states[self.pos - 1].message or ''
+
+    @property
+    def redo_msg(self):
+        if not self.can_redo:
+            return ''
+        return self.states[self.pos].message or ''