Implement disk caching of album art (#360)

* Implement disk caching of album art

This includes a button to clear the cache in the settings, as
requested.

Closes #358

* Make the cache size defaults match

* Implement the review by jonaski

* Fix more problems with the PR

src/settings/collectionsettingspage.cpp

@@ -34,6 +34,7 @@
 #include <QPushButton>
 #include <QSettings>
 
+#include "core/application.h"
 #include "core/iconloader.h"
 #include "collection/collectiondirectorymodel.h"
 #include "collectionsettingspage.h"
@@ -43,6 +44,13 @@
 #include "ui_collectionsettingspage.h"
 
 const char *CollectionSettingsPage::kSettingsGroup = "Collection";
+const char *CollectionSettingsPage::kSettingsCacheSize = "cache_size";
+const char *CollectionSettingsPage::kSettingsCacheSizeUnit = "cache_size_unit";
+const char *CollectionSettingsPage::kSettingsDiskCacheEnable = "disk_cache_enable";
+const char *CollectionSettingsPage::kSettingsDiskCacheSize = "disk_cache_size";
+const char *CollectionSettingsPage::kSettingsDiskCacheSizeUnit = "disk_cache_size_unit";
+
+const QStringList CollectionSettingsPage::cacheUnitNames = { "KB", "MB", "GB", "TB" };
 
 CollectionSettingsPage::CollectionSettingsPage(SettingsDialog *dialog)
     : SettingsPage(dialog),
@@ -91,6 +99,14 @@ void CollectionSettingsPage::CurrentRowChanged(const QModelIndex& index) {
   ui_->remove->setEnabled(index.isValid());
 }
 
+void CollectionSettingsPage::DiskCacheEnable(int state) {
+  bool checked = state == Qt::Checked;
+  ui_->button_disk_cache->setEnabled(checked);
+  ui_->label_disk_cache_size->setEnabled(checked);
+  ui_->spinbox_disk_cache_size->setEnabled(checked);
+  ui_->combobox_disk_cache_size->setEnabled(checked);
+}
+
 void CollectionSettingsPage::Load() {
 
   if (!initialised_model_) {
@@ -130,6 +146,20 @@ void CollectionSettingsPage::Load() {
   ui_->checkbox_cover_lowercase->setChecked(s.value("cover_lowercase", true).toBool());
   ui_->checkbox_cover_replace_spaces->setChecked(s.value("cover_replace_spaces", true).toBool());
 
+  ui_->spinbox_cache_size->setValue(s.value(kSettingsCacheSize, 80).toInt());
+  ui_->combobox_cache_size->addItems(cacheUnitNames);
+  ui_->combobox_cache_size->setCurrentIndex(s.value(kSettingsCacheSizeUnit, (int) CacheSizeUnit_MB).toInt());
+  ui_->checkbox_disk_cache->setChecked(s.value(kSettingsDiskCacheEnable, false).toBool());
+  ui_->label_disk_cache_size->setEnabled(ui_->checkbox_disk_cache->isChecked());
+  ui_->spinbox_disk_cache_size->setEnabled(ui_->checkbox_disk_cache->isChecked());
+  ui_->spinbox_disk_cache_size->setValue(s.value(kSettingsDiskCacheSize, 80).toInt());
+  ui_->combobox_disk_cache_size->setEnabled(ui_->checkbox_disk_cache->isChecked());
+  ui_->combobox_disk_cache_size->addItems(cacheUnitNames);
+  ui_->combobox_disk_cache_size->setCurrentIndex(s.value(kSettingsDiskCacheSizeUnit, (int) CacheSizeUnit_MB).toInt());
+
+  connect(ui_->checkbox_disk_cache, SIGNAL(stateChanged(int)), SLOT(DiskCacheEnable(int)));
+  connect(ui_->button_disk_cache, SIGNAL(clicked()), dialog()->app(), SIGNAL(ClearPixmapDiskCache()));
+
   s.endGroup();
 
 }
@@ -161,6 +191,12 @@ void CollectionSettingsPage::Save() {
   s.setValue("cover_lowercase", ui_->checkbox_cover_lowercase->isChecked());
   s.setValue("cover_replace_spaces", ui_->checkbox_cover_replace_spaces->isChecked());
 
+  s.setValue(kSettingsCacheSize, ui_->spinbox_cache_size->value());
+  s.setValue(kSettingsCacheSizeUnit, ui_->combobox_cache_size->currentIndex());
+  s.setValue(kSettingsDiskCacheEnable, ui_->checkbox_disk_cache->isChecked());
+  s.setValue(kSettingsDiskCacheSize, ui_->spinbox_disk_cache_size->value());
+  s.setValue(kSettingsDiskCacheSizeUnit, ui_->combobox_disk_cache_size->currentIndex());
+
   s.endGroup();
 
 }

src/settings/collectionsettingspage.h

@@ -39,6 +39,18 @@ public:
   ~CollectionSettingsPage();
 
   static const char *kSettingsGroup;
+  static const char *kSettingsCacheSize;
+  static const char *kSettingsCacheSizeUnit;
+  static const char *kSettingsDiskCacheEnable;
+  static const char *kSettingsDiskCacheSize;
+  static const char *kSettingsDiskCacheSizeUnit;
+
+  enum CacheSizeUnit {
+    CacheSizeUnit_KB,
+    CacheSizeUnit_MB,
+    CacheSizeUnit_GB,
+    CacheSizeUnit_TB,
+  };
 
   enum SaveCover {
     SaveCover_Hash = 1,
@@ -53,11 +65,14 @@ private slots:
   void Remove();
 
   void CurrentRowChanged(const QModelIndex &index);
+  void DiskCacheEnable(int state);
   void CoverSaveInAlbumDirChanged();
 
 private:
   Ui_CollectionSettingsPage *ui_;
   bool initialised_model_;
+
+  static const QStringList cacheUnitNames;
 };
 
 #endif  // COLLECTIONSETTINGSPAGE_H

src/settings/collectionsettingspage.ui

@@ -7,7 +7,7 @@
     <x>0</x>
     <y>0</y>
     <width>509</width>
-    <height>746</height>
+    <height>913</height>
    </rect>
   </property>
   <property name="windowTitle">
@@ -249,6 +249,99 @@ If there are no matches then it will use the largest image in the directory.</st
         </layout>
        </widget>
       </item>
+      <item>
+       <widget class="QGroupBox" name="albumArtGroupBox">
+        <property name="title">
+         <string>Album art cache</string>
+        </property>
+        <layout class="QVBoxLayout" name="verticalLayout">
+         <item>
+          <layout class="QVBoxLayout" name="verticalLayout_2">
+           <item>
+            <layout class="QHBoxLayout" name="horizontalLayout_4">
+             <item>
+              <widget class="QLabel" name="label_cache_size">
+               <property name="sizePolicy">
+                <sizepolicy hsizetype="Preferred" vsizetype="Preferred">
+                 <horstretch>0</horstretch>
+                 <verstretch>0</verstretch>
+                </sizepolicy>
+               </property>
+               <property name="text">
+                <string>Size</string>
+               </property>
+              </widget>
+             </item>
+             <item>
+              <widget class="QSpinBox" name="spinbox_cache_size">
+               <property name="maximum">
+                <number>1048576</number>
+               </property>
+              </widget>
+             </item>
+             <item>
+              <widget class="QComboBox" name="combobox_cache_size">
+               <property name="sizePolicy">
+                <sizepolicy hsizetype="Preferred" vsizetype="Preferred">
+                 <horstretch>0</horstretch>
+                 <verstretch>0</verstretch>
+                </sizepolicy>
+               </property>
+              </widget>
+             </item>
+            </layout>
+           </item>
+           <item>
+            <layout class="QHBoxLayout" name="horizontalLayout">
+             <item>
+              <widget class="QCheckBox" name="checkbox_disk_cache">
+               <property name="text">
+                <string>Enable Disk Cache</string>
+               </property>
+              </widget>
+             </item>
+             <item>
+              <widget class="QPushButton" name="button_disk_cache">
+               <property name="text">
+                <string>Clear Disk Cache</string>
+               </property>
+              </widget>
+             </item>
+            </layout>
+           </item>
+           <item>
+            <layout class="QHBoxLayout" name="horizontalLayout_5">
+             <item>
+              <widget class="QLabel" name="label_disk_cache_size">
+               <property name="text">
+                <string>Disk Cache Size</string>
+               </property>
+              </widget>
+             </item>
+             <item>
+              <widget class="QSpinBox" name="spinbox_disk_cache_size">
+               <property name="maximum">
+                <number>1048576</number>
+               </property>
+              </widget>
+             </item>
+             <item>
+              <widget class="QComboBox" name="combobox_disk_cache_size">
+               <property name="sizePolicy">
+                <sizepolicy hsizetype="Preferred" vsizetype="Preferred">
+                 <horstretch>0</horstretch>
+                 <verstretch>0</verstretch>
+                </sizepolicy>
+               </property>
+              </widget>
+             </item>
+            </layout>
+           </item>
+          </layout>
+         </item>
+        </layout>
+       </widget>
+      </item>
      </layout>
     </widget>
    </item>