Fix #855055 ("Back" button on download metadata dialog box)

src/calibre/gui2/metadata/single_download.py

@@ -538,14 +538,20 @@ class CoversModel(QAbstractListModel): # {{{
             current_cover = QPixmap(I('default_cover.png'))
 
         self.blank = QPixmap(I('blank.png')).scaled(150, 200)
+        self.cc = current_cover
+        self.reset_covers(do_reset=False)
 
-        self.covers = [self.get_item(_('Current cover'), current_cover)]
+    def reset_covers(self, do_reset=True):
+        self.covers = [self.get_item(_('Current cover'), self.cc)]
         self.plugin_map = {}
         for i, plugin in enumerate(metadata_plugins(['cover'])):
             self.covers.append((plugin.name+'\n'+_('Searching...'),
                 QVariant(self.blank), None, True))
             self.plugin_map[plugin] = i+1
 
+        if do_reset:
+            self.reset()
+
     def get_item(self, src, pmap, waiting=False):
         sz = '%dx%d'%(pmap.width(), pmap.height())
         text = QVariant(src + '\n' + sz)
@@ -654,6 +660,9 @@ class CoversView(QListView): # {{{
         self.select(0)
         self.delegate.start_animation()
 
+    def reset_covers(self):
+        self.m.reset_covers()
+
     def clear_failed(self):
         plugin = self.m.plugin_for_index(self.currentIndex())
         self.m.clear_failed()
@@ -683,12 +692,18 @@ class CoversWidget(QWidget): # {{{
         l.addWidget(self.covers_view, 1, 0)
         self.continue_processing = True
 
+    def reset_covers(self):
+        self.covers_view.reset_covers()
+
     def start(self, book, current_cover, title, authors):
+        self.continue_processing = True
+        self.abort.clear()
         self.book, self.current_cover = book, current_cover
         self.title, self.authors = title, authors
         self.log('Starting cover download for:', book.title)
         self.log('Query:', title, authors, self.book.identifiers)
-        self.msg.setText('<p>'+_('Downloading covers for <b>%s</b>, please wait...')%book.title)
+        self.msg.setText('<p>'+
+            _('Downloading covers for <b>%s</b>, please wait...')%book.title)
         self.covers_view.start()
 
         self.worker = CoverWorker(self.log, self.abort, self.title,
@@ -726,8 +741,9 @@ class CoversWidget(QWidget): # {{{
         if num < 2:
             txt = _('Could not find any covers for <b>%s</b>')%self.book.title
         else:
-            txt = _('Found <b>%(num)d</b> covers of %(title)s. Pick the one you like'
+            txt = _('Found <b>%(num)d</b> covers of %(title)s. '
-                    ' best.')%dict(num=num-1, title=self.title)
+                    'Pick the one you like best.')%dict(num=num-1,
+                            title=self.title)
         self.msg.setText(txt)
 
         self.finished.emit()
@@ -832,10 +848,14 @@ class FullFetch(QDialog): # {{{
         self.next_button.clicked.connect(self.next_clicked)
         self.ok_button = self.bb.button(self.bb.Ok)
         self.ok_button.clicked.connect(self.ok_clicked)
+        self.prev_button = self.bb.addButton(_('Back'), self.bb.ActionRole)
+        self.prev_button.setIcon(QIcon(I('back.png')))
+        self.prev_button.clicked.connect(self.back_clicked)
         self.log_button = self.bb.addButton(_('View log'), self.bb.ActionRole)
         self.log_button.clicked.connect(self.view_log)
         self.log_button.setIcon(QIcon(I('debug.png')))
         self.ok_button.setVisible(False)
+        self.prev_button.setVisible(False)
 
         self.identify_widget = IdentifyWidget(self.log, self)
         self.identify_widget.rejected.connect(self.reject)
@@ -857,12 +877,21 @@ class FullFetch(QDialog): # {{{
     def book_selected(self, book):
         self.next_button.setVisible(False)
         self.ok_button.setVisible(True)
+        self.prev_button.setVisible(True)
         self.book = book
         self.stack.setCurrentIndex(1)
         self.log('\n\n')
         self.covers_widget.start(book, self.current_cover,
                 self.title, self.authors)
 
+    def back_clicked(self):
+        self.next_button.setVisible(True)
+        self.ok_button.setVisible(False)
+        self.prev_button.setVisible(False)
+        self.stack.setCurrentIndex(0)
+        self.covers_widget.cancel()
+        self.covers_widget.reset_covers()
+
     def accept(self):
         # Prevent the usual dialog accept mechanisms from working
         pass