Fixed a few issues with re-paging after rotation

The situation when device is rotated before the current paging task
has completed wasn't handled correctly. E.g. current book position
wasn't restored after rotating the device back, page count in the
progress indicator wasn't restarted etc.

app/qml/BooksBookView.qml

@@ -43,8 +43,7 @@ SilicaFlickable {
     signal pageClicked(var page)
 
     property int _currentPage: bookListWatcher.currentIndex
-    property bool _loading: minLoadingDelay.running || !bookModel.pageCount
+    property bool _loading: minLoadingDelay.running || bookModel.loading
-    property bool _pagerVisible: (_currentState.pager && book && bookModel.pageCount) ? 1 : 0
     property var _currentState: _visibilityStates[settings.pageDetails % _visibilityStates.length]
     readonly property var _visibilityStates: [
         { pager: false, page: false, title: false, tools: false },
@@ -204,23 +203,12 @@ SilicaFlickable {
         }
         pageCount: bookModel.pageCount
         width: parent.width
-        opacity: _pagerVisible ? 1 : 0
+        opacity: _currentState.pager ? 1 : 0
-        visible: opacity > 0
+        visible: opacity > 0 && book && bookModel.pageCount && !_loading
         onPageChanged: bookView.jumpTo(page)
         Behavior on opacity { FadeAnimation {} }
     }
 
-    Column {
-        id: loadingAnimation
-        opacity: _loading ? 1 : 0
-        visible: opacity > 0
-        anchors.centerIn: parent
-        spacing: Theme.paddingLarge
-        Behavior on opacity { FadeAnimation {} }
-        Item {
-            width: busyIndicator.width
-            height: busyIndicator.height
-            anchors.horizontalCenter: parent.horizontalCenter
     BusyIndicator {
         id: busyIndicator
         anchors.centerIn: parent
@@ -229,7 +217,7 @@ SilicaFlickable {
     }
     BooksFitLabel {
         anchors {
-                    fill: parent
+            fill: busyIndicator
             margins: Theme.paddingMedium
         }
         maxFontSize: Theme.fontSizeMedium
@@ -238,16 +226,22 @@ SilicaFlickable {
         color: Theme.highlightColor
         text: bookModel.progress > 0 ? bookModel.progress : ""
         visible: opacity > 0
-                opacity: bookModel.progress > 0 ? 1 : 0
+        opacity: (_loading && bookModel.progress) > 0 ? 1 : 0
         Behavior on opacity { FadeAnimation {} }
     }
-        }
     Label {
-            anchors.horizontalCenter: parent.horizontalCenter
+        anchors {
+            top: busyIndicator.bottom
+            topMargin: Theme.paddingLarge
+            horizontalCenter: busyIndicator.horizontalCenter
+
+        }
         horizontalAlignment: Text.AlignHCenter
         color: Theme.highlightColor
+        opacity: _loading ? 1 : 0
+        visible: opacity > 0
+        Behavior on opacity { FadeAnimation {} }
         //% "Loading..."
         text: qsTrId("book-view-loading")
     }
 }
-}

app/src/BooksBookModel.cpp

@@ -403,19 +403,32 @@ void BooksBookModel::setSize(QSize aSize)
             HDEBUG("size didn't change");
         } else if (iData2 && iData2->iWidth == w && iData2->iHeight == h) {
             HDEBUG("switching to backup layout");
-            const int oldPageCount(pageCount());
+            const int oldModelPageCount = pageCount();
-            BooksPos page1 = pageMark(iCurrentPage);
+            int oldPageCount;
-            BooksPos page2 = pageMark(iCurrentPage+1);
+            BooksPos page1, page2;
+            if (iTask) {
+                // Layout has been switched back before the paging task
+                // has completed
+                HDEBUG("not so fast please...");
+                oldPageCount = iTask->iOldPageCount;
+                page1 = iTask->iPagePos;
+                page2 = iTask->iNextPagePos;
+            } else {
+                oldPageCount = oldModelPageCount;
+                page1 = pageMark(iCurrentPage);
+                page2 = pageMark(iCurrentPage+1);
+            }
             Data* tmp = iData;
             iData = iData2;
             iData2 = tmp;
             if (iData) {
                 // Cancel unnecessary paging task
                 if (iTask) {
+                    BooksLoadingSignalBlocker block(this);
                     iTask->release(this);
                     iTask = NULL;
                 }
-                updateModel(oldPageCount);
+                updateModel(oldModelPageCount);
                 Q_EMIT pageMarksChanged();
                 Q_EMIT jumpToPage(iData->pickPage(page1, page2, oldPageCount));
             } else {
@@ -459,6 +472,8 @@ void BooksBookModel::startReset(bool aFullReset)
     iData = NULL;
 
     if (iBook && width() > 0 && height() > 0) {
+        HDEBUG("starting" << qPrintable(QString("%1x%2").arg(width()).
+            arg(height())) << "paging");
         iTask = new Task(this, iBook->bookRef(), thisPage, nextPage,
             iBook->lastPos(), oldPageCount);
         iTaskQueue->submit(iTask);
@@ -483,7 +498,9 @@ void BooksBookModel::startReset(bool aFullReset)
 
 void BooksBookModel::onResetProgress(int aProgress)
 {
-    if (iTask && aProgress > iProgress) {
+    // progress -> onResetProgress is a queued connection, we may received
+    // this event from the task that has already been canceled.
+    if (iTask == sender() && aProgress > iProgress) {
         iProgress = aProgress;
         Q_EMIT progressChanged();
     }