BinEditor: Request new range when start/end of current one is reached.

Task-number: QTCREATORBUG-1488

src/plugins/bineditor/bineditor.cpp

@@ -150,6 +150,7 @@ void BinEditor::init()
     horizontalScrollBar()->setPageStep(viewport()->width());
     verticalScrollBar()->setRange(0, m_numLines - m_numVisibleLines);
     verticalScrollBar()->setPageStep(m_numVisibleLines);
+    ensureCursorVisible();
 }
 
 
@@ -393,7 +394,10 @@ bool BinEditor::save(const QString &oldFileName, const QString &newFileName)
             if (output.write(it.value()) < m_blockSize)
                 return false;
         }
-        if (size % m_blockSize != 0 && !output.resize(size))
+
+        // We may have padded the displayed data, so we have to make sure
+        // changes to that area are not actually written back to disk.
+        if (!output.resize(size))
             return false;
     } else {
         QFile output(newFileName);
@@ -445,6 +449,14 @@ void BinEditor::resizeEvent(QResizeEvent *)
 void BinEditor::scrollContentsBy(int dx, int dy)
 {
     viewport()->scroll(isRightToLeft() ? -dx : dx, dy * m_lineHeight);
+    if (m_inLazyMode) {
+        const QScrollBar * const scrollBar = verticalScrollBar();
+        const int scrollPos = scrollBar->value();
+        if (dy <= 0 && scrollPos == scrollBar->maximum())
+            emit endOfRangeReached(editorInterface());
+        else if (dy >= 0 && scrollPos == scrollBar->minimum())
+            emit startOfRangeReached(editorInterface());
+    }
 }
 
 void BinEditor::changeEvent(QEvent *e)
@@ -1009,6 +1021,15 @@ bool BinEditor::event(QEvent *e) {
             ensureCursorVisible();
             e->accept();
             return true;
+        case Qt::Key_Down:
+            if (m_inLazyMode) {
+                const QScrollBar * const scrollBar = verticalScrollBar();
+                if (scrollBar->value() >= scrollBar->maximum() - 1) {
+                    emit endOfRangeReached(editorInterface());
+                    return true;
+                }
+            }
+            break;
         default:;
         }
     }

src/plugins/bineditor/bineditor.h

@@ -66,6 +66,7 @@ public:
     QByteArray data() const;
 
     inline int dataSize() const { return m_size; }
+    quint64 baseAddress() const { return m_baseAddr; }
 
     inline bool inLazyMode() const { return m_inLazyMode; }
     Q_INVOKABLE void setLazyData(quint64 startAddr, int range, int blockSize = 4096);
@@ -130,6 +131,8 @@ Q_SIGNALS:
 
     void lazyDataRequested(Core::IEditor *editor, quint64 block, bool synchronous);
     void newWindowRequested(quint64 address);
+    void startOfRangeReached(Core::IEditor *editor);
+    void endOfRangeReached(Core::IEditor *editor);
 
 protected:
     void scrollContentsBy(int dx, int dy);

src/plugins/bineditor/bineditorplugin.cpp

@@ -179,6 +179,10 @@ public:
         m_editor = parent;
         connect(m_editor, SIGNAL(lazyDataRequested(Core::IEditor *, quint64, bool)),
             this, SLOT(provideData(Core::IEditor *, quint64)));
+        connect(m_editor, SIGNAL(startOfRangeReached(Core::IEditor*)),
+            this, SLOT(handleStartOfRangeReached()));
+        connect(m_editor, SIGNAL(endOfRangeReached(Core::IEditor*)),
+            this, SLOT(handleEndOfRangeReached()));
     }
     ~BinEditorFile() {}
 
@@ -196,15 +200,15 @@ public:
         }
     }
 
-    bool open(const QString &fileName) {
+    bool open(const QString &fileName, quint64 offset = 0) {
         QFile file(fileName);
         if (file.open(QIODevice::ReadOnly)) {
             m_fileName = fileName;
-            if (file.isSequential() && file.size() <= 64 * 1024 * 1024) {
+            qint64 maxRange = 64 * 1024 * 1024;
+            if (file.isSequential() && file.size() <= maxRange) {
                 m_editor->setData(file.readAll());
             } else {
-                m_editor->setLazyData(0, qMin(file.size(),
-                                              static_cast<qint64>(INT_MAX-16)));
+                m_editor->setLazyData(offset, maxRange);
                 m_editor->editorInterface()->
                         setDisplayName(QFileInfo(fileName).fileName());
             }
@@ -221,12 +225,30 @@ private slots:
             int blockSize = m_editor->lazyDataBlockSize();
             file.seek(block * blockSize);
             QByteArray data = file.read(blockSize);
-            if (data.size() != blockSize)
-                data.resize(blockSize);
+            const int dataSize = data.size();
+            if (dataSize != blockSize)
+                data += QByteArray(blockSize - dataSize, 0);
             m_editor->addLazyData(block, data);
             file.close();
         }
     }
+
+    void handleStartOfRangeReached()
+    {
+        if (m_editor->baseAddress() != 0) {
+            open(m_fileName, m_editor->baseAddress());
+        }
+    }
+
+    void handleEndOfRangeReached()
+    {
+        const quint64 currentEndAdress
+            = m_editor->baseAddress() + m_editor->dataSize();
+        if (currentEndAdress
+            < static_cast<quint64>(QFileInfo(m_fileName).size()))
+            open(m_fileName, currentEndAdress);
+    }
+
 public:
 
     void setFilename(const QString &filename) {