Improve seek backward and outside of function in Decompiler widget (#1916)

* Improve seek backward and outside of function
* Improve seekToReference

src/common/CutterSeekable.cpp

@@ -62,3 +62,25 @@ bool CutterSeekable::isSynchronized()
 {
     return synchronized;
 }
+
+void CutterSeekable::seekToReference(RVA offset)
+{
+    if (offset == RVA_INVALID)
+    {
+        return;
+    }
+    
+    RVA target;
+    QList<XrefDescription> refs = Core()->getXRefs(offset, false, false);
+    
+    if (refs.length()) {
+        if (refs.length() > 1) {
+            qWarning() << "Too many references here. Weird behaviour expected.";
+        }
+        
+        target = refs.at(0).to;
+        if (target != RVA_INVALID) {
+            seek(target);
+        }
+    }
+}

src/common/CutterSeekable.h

@@ -44,6 +44,12 @@ public:
      */
     bool isSynchronized();
 
+    /**
+     * @brief seekToReference will seek to the function or the object which is referenced in a given offset
+     * @param offset - an address that contains a reference to jump to
+     */
+    void seekToReference(RVA offset);
+
 public slots:
     /**
      * @brief seekPrev seeks to last location.

src/widgets/DecompilerWidget.cpp

@@ -7,6 +7,7 @@
 #include "common/TempConfig.h"
 #include "common/SelectionHighlight.h"
 #include "common/Decompiler.h"
+#include "common/CutterSeekable.h"
 
 #include <QTextEdit>
 #include <QPlainTextEdit>
@@ -23,6 +24,9 @@ DecompilerWidget::DecompilerWidget(MainWindow *main, QAction *action) :
 
     syntaxHighlighter = Config()->createSyntaxHighlighter(ui->textEdit->document());
 
+    // Event filter to intercept double clicks in the textbox
+    ui->textEdit->viewport()->installEventFilter(this);
+
     setupFonts();
     colorsUpdatedSlot();
 
@@ -88,6 +92,13 @@ DecompilerWidget::DecompilerWidget(MainWindow *main, QAction *action) :
     connect(Core(), &CutterCore::commentsChanged, this, &DecompilerWidget::doAutoRefresh);
     connect(Core(), &CutterCore::instructionChanged, this, &DecompilerWidget::doAutoRefresh);
     connect(Core(), &CutterCore::refreshCodeViews, this, &DecompilerWidget::doAutoRefresh);
+
+    // Esc to seek backward
+    QAction *seekPrevAction = new QAction(this);
+    seekPrevAction->setShortcut(Qt::Key_Escape);
+    seekPrevAction->setShortcutContext(Qt::WidgetWithChildrenShortcut);
+    addAction(seekPrevAction);
+    connect(seekPrevAction, &QAction::triggered, seekable, &CutterSeekable::seekPrev);
 }
 
 DecompilerWidget::~DecompilerWidget() = default;
@@ -295,3 +306,24 @@ void DecompilerWidget::showDisasContextMenu(const QPoint &pt)
     mCtxMenu->exec(ui->textEdit->mapToGlobal(pt));
     doRefresh();
 }
+
+void DecompilerWidget::seekToReference()
+{
+    size_t pos = ui->textEdit->textCursor().position();
+    RVA offset = code.OffsetForPosition(pos);
+    seekable->seekToReference(offset);
+}
+
+bool DecompilerWidget::eventFilter(QObject *obj, QEvent *event)
+{
+    if (event->type() == QEvent::MouseButtonDblClick
+        && (obj == ui->textEdit || obj == ui->textEdit->viewport())) {
+        QMouseEvent *mouseEvent = static_cast<QMouseEvent *>(event);
+
+        const QTextCursor& cursor = ui->textEdit->cursorForPosition(QPoint(mouseEvent->x(), mouseEvent->y()));
+        seekToReference();
+        return true;
+    }
+
+    return MemoryDockWidget::eventFilter(obj, event);
+}

src/widgets/DecompilerWidget.h

@@ -70,6 +70,13 @@ private:
     void updateCursorPosition();
 
     QString getWindowTitle() const override;
+    bool eventFilter(QObject *obj, QEvent *event) override;
+
+    /**
+     * @brief a wrapper around CutterSeekable::seekToReference to seek to an object which is
+     * referenced from the address under cursor
+     */
+    void seekToReference();
 };
 
 #endif // DECOMPILERWIDGET_H

src/widgets/DisassemblerGraphView.cpp

@@ -996,18 +996,7 @@ void DisassemblerGraphView::blockDoubleClicked(GraphView::GraphBlock &block, QMo
                                                QPoint pos)
 {
     Q_UNUSED(event);
-
-    RVA instr = getAddrForMouseEvent(block, &pos);
-    if (instr == RVA_INVALID) {
-        return;
-    }
-    QList<XrefDescription> refs = Core()->getXRefs(instr, false, false);
-    if (refs.length()) {
-        seekable->seek(refs.at(0).to);
-    }
-    if (refs.length() > 1) {
-        qWarning() << "Too many references here. Weird behaviour expected.";
-    }
+    seekable->seekToReference(getAddrForMouseEvent(block, &pos));
 }
 
 void DisassemblerGraphView::blockHelpEvent(GraphView::GraphBlock &block, QHelpEvent *event,

src/widgets/DisassemblyWidget.cpp

@@ -617,20 +617,7 @@ void DisassemblyWidget::moveCursorRelative(bool up, bool page)
 void DisassemblyWidget::jumpToOffsetUnderCursor(const QTextCursor &cursor)
 {
     RVA offset = readDisassemblyOffset(cursor);
-    RVA jump = Core()->getOffsetJump(offset);
-
-    if (jump == RVA_INVALID) {
-        bool ok;
-        RVA xref = Core()->cmdj("axfj@" + QString::number(
-                                              offset)).array().first().toObject().value("to").toVariant().toULongLong(&ok);
-        if (ok) {
-            jump = xref;
-        }
-    }
-
-    if (jump != RVA_INVALID) {
-        seekable->seek(jump);
-    }
+    seekable->seekToReference(offset);
 }
 
 bool DisassemblyWidget::eventFilter(QObject *obj, QEvent *event)