Keep topOffset history in disassembly widget. (#3171)

This commit adds support for a `topOffset` history (on top of the
rizin-managed history), that keeps track of the offset of the top
instruction in the disassembly widget.

closes #2970

src/common/CutterSeekable.cpp

@@ -13,18 +13,18 @@ CutterSeekable::~CutterSeekable() {}
 void CutterSeekable::setSynchronization(bool sync)
 {
     synchronized = sync;
-    onCoreSeekChanged(Core()->getOffset());
+    onCoreSeekChanged(Core()->getOffset(), CutterCore::SeekHistoryType::New);
     emit syncChanged();
 }
 
-void CutterSeekable::onCoreSeekChanged(RVA addr)
+void CutterSeekable::onCoreSeekChanged(RVA addr, CutterCore::SeekHistoryType type)
 {
     if (synchronized && widgetOffset != addr) {
-        updateSeek(addr, true);
+        updateSeek(addr, type, true);
     }
 }
 
-void CutterSeekable::updateSeek(RVA addr, bool localOnly)
+void CutterSeekable::updateSeek(RVA addr, CutterCore::SeekHistoryType type, bool localOnly)
 {
     previousOffset = widgetOffset;
     widgetOffset = addr;
@@ -32,7 +32,7 @@ void CutterSeekable::updateSeek(RVA addr, bool localOnly)
         Core()->seek(addr);
     }
 
-    emit seekableSeekChanged(addr);
+    emit seekableSeekChanged(addr, type);
 }
 
 void CutterSeekable::seekPrev()
@@ -40,7 +40,7 @@ void CutterSeekable::seekPrev()
     if (synchronized) {
         Core()->seekPrev();
     } else {
-        this->seek(previousOffset);
+        this->seek(previousOffset, CutterCore::SeekHistoryType::Undo);
     }
 }
 

src/common/CutterSeekable.h

@@ -19,8 +19,12 @@ public:
      * signal will be emitted.
      * In any case, CutterSeekable::seekableSeekChanged is emitted.
      * @param addr the location to seek at.
+     * @param type the type of seek wrt history (Undo, Redo, or New)
      */
-    void seek(RVA addr) { updateSeek(addr, false); }
+    void seek(RVA addr, CutterCore::SeekHistoryType type = CutterCore::SeekHistoryType::New)
+    {
+        updateSeek(addr, type, false);
+    }
 
     /**
      * @brief setSynchronization sets
@@ -67,7 +71,7 @@ private slots:
     /**
      * @brief onCoreSeekChanged
      */
-    void onCoreSeekChanged(RVA addr);
+    void onCoreSeekChanged(RVA addr, CutterCore::SeekHistoryType type);
 
 private:
     /**
@@ -91,9 +95,9 @@ private:
      * @brief internal method for changing the seek
      * @param localOnly whether the seek should be updated globally if synchronized
      */
-    void updateSeek(RVA addr, bool localOnly);
+    void updateSeek(RVA addr, CutterCore::SeekHistoryType type, bool localOnly);
 
 signals:
-    void seekableSeekChanged(RVA addr);
+    void seekableSeekChanged(RVA addr, CutterCore::SeekHistoryType type);
     void syncChanged();
 };

src/core/Cutter.cpp

@@ -1002,19 +1002,19 @@ void CutterCore::seekPrev()
 {
     CORE_LOCK();
     rz_core_seek_undo(core);
-    updateSeek();
+    updateSeek(SeekHistoryType::Undo);
 }
 
 void CutterCore::seekNext()
 {
     CORE_LOCK();
     rz_core_seek_redo(core);
-    updateSeek();
+    updateSeek(SeekHistoryType::Redo);
 }
 
-void CutterCore::updateSeek()
+void CutterCore::updateSeek(SeekHistoryType type)
 {
-    emit seekChanged(getOffset());
+    emit seekChanged(getOffset(), type);
 }
 
 RVA CutterCore::prevOpAddr(RVA startAddr, int count)

src/core/Cutter.h

@@ -172,6 +172,8 @@ public:
         return returner;
     }
 
+    enum class SeekHistoryType { New, Undo, Redo };
+
     CutterJson cmdj(const char *str);
     CutterJson cmdj(const QString &str) { return cmdj(str.toUtf8().constData()); }
     QString cmdTask(const QString &str);
@@ -324,7 +326,7 @@ public:
     void seekSilent(QString thing) { seekSilent(math(thing)); }
     void seekPrev();
     void seekNext();
-    void updateSeek();
+    void updateSeek(SeekHistoryType type = SeekHistoryType::New);
     /**
      * @brief Raise a memory widget showing current offset, prefer last active
      * memory widget.
@@ -794,8 +796,9 @@ signals:
     /**
      * @brief seekChanged is emitted each time Rizin's seek value is modified
      * @param offset
+     * @param historyType
      */
-    void seekChanged(RVA offset);
+    void seekChanged(RVA offset, SeekHistoryType type = SeekHistoryType::New);
 
     void toggleDebugView();
 

src/widgets/DisassemblyWidget.cpp

@@ -327,6 +327,7 @@ void DisassemblyWidget::scrollInstructions(int count)
     }
 
     refreshDisasm(offset);
+    topOffsetHistory[topOffsetHistoryPos] = offset;
 }
 
 bool DisassemblyWidget::updateMaxLines()
@@ -660,19 +661,32 @@ QString DisassemblyWidget::getWindowTitle() const
     return tr("Disassembly");
 }
 
-void DisassemblyWidget::on_seekChanged(RVA offset)
+void DisassemblyWidget::on_seekChanged(RVA offset, CutterCore::SeekHistoryType type)
 {
+    if (type == CutterCore::SeekHistoryType::New) {
+        // Erase previous history past this point.
+        topOffsetHistory.erase(topOffsetHistory.begin() + topOffsetHistoryPos + 1,
+                               topOffsetHistory.end());
+        topOffsetHistory.push_back(offset);
+        topOffsetHistoryPos = topOffsetHistory.size() - 1;
+    } else if (type == CutterCore::SeekHistoryType::Undo) {
+        --topOffsetHistoryPos;
+    } else if (type == CutterCore::SeekHistoryType::Redo) {
+        ++topOffsetHistoryPos;
+    }
     if (!seekFromCursor) {
         cursorLineOffset = 0;
         cursorCharOffset = 0;
     }
 
-    if (topOffset != RVA_INVALID && offset >= topOffset && offset <= bottomOffset) {
+    if (topOffset != RVA_INVALID && offset >= topOffset && offset <= bottomOffset
+        && type == CutterCore::SeekHistoryType::New) {
         // if the line with the seek offset is currently visible, just move the cursor there
         updateCursorPosition();
+        topOffsetHistory[topOffsetHistoryPos] = topOffset;
     } else {
         // otherwise scroll there
-        refreshDisasm(offset);
+        refreshDisasm(topOffsetHistory[topOffsetHistoryPos]);
     }
     mCtxMenu->setOffset(offset);
 }

src/widgets/DisassemblyWidget.h

@@ -51,7 +51,7 @@ public slots:
     QList<DisassemblyLine> getLines();
 
 protected slots:
-    void on_seekChanged(RVA offset);
+    void on_seekChanged(RVA offset, CutterCore::SeekHistoryType type);
     void refreshIfInRange(RVA offset);
     void refreshDisasm(RVA offset = RVA_INVALID);
 
@@ -87,6 +87,9 @@ private:
     void keyPressEvent(QKeyEvent *event) override;
     QString getWindowTitle() const override;
 
+    int topOffsetHistoryPos = 0;
+    QList<RVA> topOffsetHistory;
+
     QList<RVA> breakpoints;
 
     void setupFonts();