FEATURE: Remember previous save paths in torrent addition dialog (closes #579305)

Changelog

@@ -1,5 +1,6 @@
 * Unreleased - Christophe Dumez <chris@qbittorrent.org> - v2.3.0
     - FEATURE: Simplified torrent root folder renaming/truncating (< v2.3.0 is no longer forward compatible)
+    - FEATURE: Remember previous save paths in torrent addition dialog
     - FEATURE: Max number of half-open connections can now be edited
     - FEATURE: Added support for strict super seeding
     - FEATURE: The user can force listening on a particular network interface

src/torrentadditiondlg.h

@@ -68,6 +68,7 @@ public:
   void saveSettings();
   void showLoadMagnetURI(QString magnet_uri);
   void showLoad(QString filePath, QString from_url=QString::null);
+  QString getCurrentTruncatedSavePath() const;
 
 public slots:
   void displayContentListMenu(const QPoint&);
@@ -80,6 +81,8 @@ public slots:
   void on_OkButton_clicked();
   void renameTorrentNameInModel(QString file_path);
   void hideTorrentContent();
+  void saveTruncatedPathHistory();
+  QStringList getSavePathHistory() const;
 
 public slots:
   void updateLabelInSavePath(QString label);

src/ui/torrentadditiondlg.ui

@@ -6,7 +6,7 @@
    <rect>
     <x>0</x>
     <y>0</y>
-    <width>585</width>
+    <width>560</width>
     <height>517</height>
    </rect>
   </property>
@@ -29,20 +29,14 @@
     </widget>
    </item>
    <item>
-    <layout class="QHBoxLayout">
-     <property name="spacing">
-      <number>6</number>
-     </property>
-     <property name="margin">
-      <number>0</number>
-     </property>
+    <layout class="QHBoxLayout" name="horizontalLayout_2">
      <item>
       <widget class="QLabel" name="savePathLbl">
-       <property name="font">
-        <font>
-         <weight>50</weight>
-         <bold>false</bold>
-        </font>
+       <property name="sizePolicy">
+        <sizepolicy hsizetype="Minimum" vsizetype="Preferred">
+         <horstretch>0</horstretch>
+         <verstretch>0</verstretch>
+        </sizepolicy>
        </property>
        <property name="text">
         <string>Save path:</string>
@@ -50,7 +44,17 @@
       </widget>
      </item>
      <item>
-      <widget class="QLineEdit" name="savePathTxt"/>
+      <widget class="QComboBox" name="savePathTxt">
+       <property name="sizePolicy">
+        <sizepolicy hsizetype="MinimumExpanding" vsizetype="Fixed">
+         <horstretch>0</horstretch>
+         <verstretch>0</verstretch>
+        </sizepolicy>
+       </property>
+       <property name="editable">
+        <bool>true</bool>
+       </property>
+      </widget>
      </item>
      <item>
       <widget class="QToolButton" name="browseButton">