minor-fix: Vim mode and VImagePreviewer

1. In Vim mode use the `undo()` and `redo()` slots of VMdEdit instead of
QTextDocument;
2. VImagePreviewer will clear the undo/redo stacks if it is empty
before;
3. Remove setLineDistanceHeight();

src/utils/vvim.cpp

@@ -4547,7 +4547,7 @@ void VVim::processUndoAction(QList<Token> &p_tokens)
     QTextDocument *doc = m_editor->document();
     int i = 0;
     for (i = 0; i < repeat && doc->isUndoAvailable(); ++i) {
-        doc->undo();
+        m_editor->undo();
     }
 
     message(tr("Undo %1 %2").arg(i).arg(i > 1 ? tr("changes") : tr("change")));
@@ -4569,7 +4569,7 @@ void VVim::processRedoAction(QList<Token> &p_tokens)
     QTextDocument *doc = m_editor->document();
     int i = 0;
     for (i = 0; i < repeat && doc->isRedoAvailable(); ++i) {
-        doc->redo();
+        m_editor->redo();
     }
 
     message(tr("Redo %1 %2").arg(i).arg(i > 1 ? tr("changes") : tr("change")));

src/vedit.cpp

@@ -154,8 +154,6 @@ void VEdit::reloadFile()
 {
     setHtml(m_file->getContent());
 
-    setBlockLineDistanceHeight();
-
     setModified(false);
 }
 
@@ -1278,31 +1276,6 @@ void VEdit::alterContextMenu(QMenu *p_menu, const QList<QAction *> &p_actions)
     Q_UNUSED(p_actions);
 }
 
-void VEdit::setBlockLineDistanceHeight()
-{
-    if (m_config.m_lineDistanceHeight <= 0) {
-        return;
-    }
-
-    bool modified = isModified();
-    QTextCursor cursor = textCursor();
-    int anchorPos = cursor.selectionStart();
-    int cursorPos = cursor.selectionEnd();
-
-    QTextBlockFormat fmt = cursor.blockFormat();
-    fmt.setLineHeight(m_config.m_lineDistanceHeight,
-                      QTextBlockFormat::LineDistanceHeight);
-    cursor.select(QTextCursor::Document);
-    cursor.mergeBlockFormat(fmt);
-
-    cursor.setPosition(anchorPos);
-    cursor.setPosition(cursorPos, QTextCursor::KeepAnchor);
-
-    setTextCursor(cursor);
-
-    setModified(modified);
-}
-
 void VEdit::updateBlockLineDistanceHeight(int p_pos,
                                           int p_charsRemoved,
                                           int p_charsAdded)

src/vedit.h

@@ -214,9 +214,6 @@ protected:
     // Called in contextMenuEvent() to modify the context menu.
     virtual void alterContextMenu(QMenu *p_menu, const QList<QAction *> &p_actions);
 
-    // Set all the blocks' line height.
-    void setBlockLineDistanceHeight();
-
 private:
     QLabel *m_wrapLabel;
     QTimer *m_labelTimer;

src/vimagepreviewer.cpp

@@ -91,6 +91,7 @@ void VImagePreviewer::previewImageLinks(QVector<ImageLinkInfo> &p_imageLinks,
                                         QTextCursor &p_cursor)
 {
     bool hasNewPreview = false;
+    EditStatus status;
     for (int i = 0; i < p_imageLinks.size(); ++i) {
         ImageLinkInfo &link = p_imageLinks[i];
         if (link.m_previewImageID > -1) {
@@ -109,7 +110,7 @@ void VImagePreviewer::previewImageLinks(QVector<ImageLinkInfo> &p_imageLinks,
 
         updateImageWidth(imgFormat);
 
-        bool isModified = m_edit->isModified();
+        saveEditStatus(status);
         p_cursor.joinPreviousEditBlock();
         p_cursor.setPosition(link.m_endPos);
         if (link.m_isBlock) {
@@ -120,7 +121,7 @@ void VImagePreviewer::previewImageLinks(QVector<ImageLinkInfo> &p_imageLinks,
         p_cursor.insertImage(imgFormat);
         p_cursor.endEditBlock();
 
-        m_edit->setModified(isModified);
+        restoreEditStatus(status);
 
         Q_ASSERT(!m_previewImages.contains(info.m_id));
         m_previewImages.insert(info.m_id, info);
@@ -190,6 +191,8 @@ bool VImagePreviewer::clearObsoletePreviewImagesOfBlock(QTextBlock &p_block,
     bool hasObsolete = false;
     bool hasOtherChars = false;
     bool hasValidPreview = false;
+    EditStatus status;
+
     // From back to front.
     for (int i = text.size() - 1; i >= 0; --i) {
         if (text[i].isSpace()) {
@@ -211,12 +214,12 @@ bool VImagePreviewer::clearObsoletePreviewImagesOfBlock(QTextBlock &p_block,
             if (it == m_previewImages.end()) {
                 // It is obsolete since we can't find it in the cache.
                 qDebug() << "remove obsolete preview image" << imageID;
-                bool isModified = m_edit->isModified();
+                saveEditStatus(status);
                 p_cursor.joinPreviousEditBlock();
                 p_cursor.setPosition(pos);
                 p_cursor.deleteChar();
                 p_cursor.endEditBlock();
-                m_edit->setModified(isModified);
+                restoreEditStatus(status);
                 hasObsolete = true;
             } else {
                 hasValidPreview = true;
@@ -229,12 +232,12 @@ bool VImagePreviewer::clearObsoletePreviewImagesOfBlock(QTextBlock &p_block,
     if (hasObsolete && !hasOtherChars && !hasValidPreview) {
         // Delete the whole block.
         qDebug() << "delete a preview block" << p_block.blockNumber();
-        bool isModified = m_edit->isModified();
+        saveEditStatus(status);
         p_cursor.joinPreviousEditBlock();
         p_cursor.setPosition(p_block.position());
         VEditUtils::removeBlock(p_cursor);
         p_cursor.endEditBlock();
-        m_edit->setModified(isModified);
+        restoreEditStatus(status);
     }
 
     return hasObsolete;
@@ -572,6 +575,8 @@ bool VImagePreviewer::updatePreviewImageWidthOfBlock(const QTextBlock &p_block,
 {
     QString text = p_block.text();
     bool updated = false;
+    EditStatus status;
+
     // From back to front.
     for (int i = text.size() - 1; i >= 0; --i) {
         if (text[i].isSpace()) {
@@ -586,14 +591,14 @@ bool VImagePreviewer::updatePreviewImageWidthOfBlock(const QTextBlock &p_block,
             if (imageFormat.isValid()
                 && isImageSourcePreviewImage(imageFormat)
                 && updateImageWidth(imageFormat)) {
-                bool isModified = m_edit->isModified();
+                saveEditStatus(status);
                 p_cursor.joinPreviousEditBlock();
                 p_cursor.setPosition(pos);
                 p_cursor.movePosition(QTextCursor::Right, QTextCursor::KeepAnchor, 1);
                 Q_ASSERT(p_cursor.charFormat().toImageFormat().isValid());
                 p_cursor.setCharFormat(imageFormat);
                 p_cursor.endEditBlock();
-                m_edit->setModified(isModified);
+                restoreEditStatus(status);
                 updated = true;
             }
         }
@@ -622,3 +627,36 @@ void VImagePreviewer::shrinkImageCache()
         }
     }
 }
+
+void VImagePreviewer::saveEditStatus(EditStatus &p_status) const
+{
+    p_status.m_modified = m_edit->isModified();
+    p_status.m_undoAvailable = m_document->isUndoAvailable();
+    p_status.m_redoAvailable = m_document->isRedoAvailable();
+}
+
+void VImagePreviewer::restoreEditStatus(const EditStatus &p_status)
+{
+    int st = 0;
+    if (!p_status.m_undoAvailable) {
+        st |= 1;
+    }
+
+    if (!p_status.m_redoAvailable) {
+        st |= 2;
+    }
+
+    if (st > 0) {
+        QTextDocument::Stacks stack = QTextDocument::UndoStack;
+        if (st == 2) {
+            stack = QTextDocument::RedoStack;
+        } else if (st == 3) {
+            stack = QTextDocument::UndoAndRedoStacks;
+        }
+
+        m_document->clearUndoRedoStacks(stack);
+    }
+
+    // Clear undo and redo stacks will change the state to modified.
+    m_edit->setModified(p_status.m_modified);
+}

src/vimagepreviewer.h

@@ -112,6 +112,19 @@ private:
         bool m_isBlock;
     };
 
+    // Status about the VMdEdit, used for restore.
+    struct EditStatus
+    {
+        EditStatus()
+            : m_modified(false), m_undoAvailable(false), m_redoAvailable(false)
+        {
+        }
+
+        bool m_modified;
+        bool m_undoAvailable;
+        bool m_redoAvailable;
+    };
+
     // Kick off new preview of m_imageRegions.
     void kickOffPreview(const QVector<VElementRegion> &p_imageRegions);
 
@@ -178,6 +191,9 @@ private:
     // Clean up image cache.
     void shrinkImageCache();
 
+    void saveEditStatus(EditStatus &p_status) const;
+    void restoreEditStatus(const EditStatus &p_status);
+
     VMdEdit *m_edit;
     QTextDocument *m_document;
     VFile *m_file;

src/vmdedit.cpp

@@ -110,8 +110,6 @@ void VMdEdit::reloadFile()
 
     setPlainText(content);
 
-    setBlockLineDistanceHeight();
-
     setModified(false);
 }