preview: add cache for code block in-place preview

src/vlivepreviewhelper.cpp

@@ -1,6 +1,5 @@
 #include "vlivepreviewhelper.h"
 
-#include <QDebug>
 #include <QByteArray>
 
 #include "veditor.h"
@@ -30,8 +29,6 @@ extern VMainWindow *g_mainWin;
 
 #define INDEX_MASK 0x00ffffffUL
 
-#define SCALE_FACTOR_THRESHOLD 1.1
-
 CodeBlockPreviewInfo::CodeBlockPreviewInfo()
 {
 }
@@ -41,33 +38,12 @@ CodeBlockPreviewInfo::CodeBlockPreviewInfo(const VCodeBlock &p_cb)
 {
 }
 
-void CodeBlockPreviewInfo::updateNonContent(const QTextDocument *p_doc,
-                                            const VCodeBlock &p_cb)
-{
-    m_codeBlock.updateNonContent(p_cb);
-    if (m_inplacePreview.isNull()) {
-        return;
-    }
-
-    QTextBlock block = p_doc->findBlockByNumber(m_codeBlock.m_endBlock);
-    if (block.isValid()) {
-        m_inplacePreview->m_startPos = block.position();
-        m_inplacePreview->m_endPos = block.position() + block.length();
-        m_inplacePreview->m_blockPos = block.position();
-        m_inplacePreview->m_blockNumber = m_codeBlock.m_endBlock;
-        // Padding is not changed since content is not changed.
-    } else {
-        m_inplacePreview.clear();
-    }
-}
-
 void CodeBlockPreviewInfo::updateInplacePreview(const VEditor *p_editor,
                                                 const QTextDocument *p_doc,
-                                                qreal p_scaleFactor)
+                                                const QPixmap &p_image)
 {
     QTextBlock block = p_doc->findBlockByNumber(m_codeBlock.m_endBlock);
     if (block.isValid()) {
-        Qt::TransformationMode tMode = Qt::SmoothTransformation;
         VImageToPreview *preview = new VImageToPreview();
 
         preview->m_startPos = block.position();
@@ -79,29 +55,7 @@ void CodeBlockPreviewInfo::updateInplacePreview(const VEditor *p_editor,
         preview->m_name = QString::number(getImageIndex());
         preview->m_isBlock = true;
 
-        if (hasImageData()) {
-            if (p_scaleFactor < SCALE_FACTOR_THRESHOLD) {
-                preview->m_image.loadFromData(m_imgData.toUtf8(),
-                                              m_imgFormat.toLocal8Bit().data());
-            } else {
-                QPixmap tmpImg;
-                tmpImg.loadFromData(m_imgData.toUtf8(),
-                                    m_imgFormat.toLocal8Bit().data());
-                preview->m_image = tmpImg.scaledToWidth(tmpImg.width() * p_scaleFactor, tMode);
-            }
-        } else if (hasImageDataBa()) {
-            if (p_scaleFactor < SCALE_FACTOR_THRESHOLD) {
-                preview->m_image.loadFromData(m_imgDataBa,
-                                              m_imgFormat.toLocal8Bit().data());
-            } else {
-                QPixmap tmpImg;
-                tmpImg.loadFromData(m_imgDataBa,
-                                    m_imgFormat.toLocal8Bit().data());
-                preview->m_image = tmpImg.scaledToWidth(tmpImg.width() * p_scaleFactor, tMode);
-            }
-        } else {
-            preview->m_image = QPixmap();
-        }
+        preview->m_image = p_image;
 
         m_inplacePreview.reset(preview);
     } else {
@@ -110,6 +64,9 @@ void CodeBlockPreviewInfo::updateInplacePreview(const VEditor *p_editor,
 }
 
 
+#define CODE_BLOCK_IMAGE_CACHE_SIZE_DIFF 10
+#define CODE_BLOCK_IMAGE_CACHE_TIME_DIFF 5
+
 VLivePreviewHelper::VLivePreviewHelper(VEditor *p_editor,
                                        VDocument *p_document,
                                        QObject *p_parent)
@@ -144,13 +101,26 @@ VLivePreviewHelper::VLivePreviewHelper(VEditor *p_editor,
             this, &VLivePreviewHelper::mathjaxPreviewResultReady);
 }
 
-bool VLivePreviewHelper::isPreviewLang(const QString &p_lang) const
+void VLivePreviewHelper::checkLang(const QString &p_lang,
+                                   bool &p_livePreview,
+                                   bool &p_inplacePreview) const
 {
-    return (m_flowchartEnabled && (p_lang == "flow" || p_lang == "flowchart"))
-           || (m_mermaidEnabled && p_lang == "mermaid")
-           || (m_plantUMLMode != PlantUMLMode::DisablePlantUML && p_lang == "puml")
-           || (m_graphvizEnabled && p_lang == "dot")
-           || (m_mathjaxEnabled && p_lang == "mathjax");
+    if (m_flowchartEnabled && (p_lang == "flow" || p_lang == "flowchart")) {
+        p_livePreview = p_inplacePreview = true;
+    } else if (m_plantUMLMode != PlantUMLMode::DisablePlantUML && p_lang == "puml") {
+        p_livePreview = true;
+        p_inplacePreview = m_plantUMLMode == PlantUMLMode::LocalPlantUML;
+    } else if (m_graphvizEnabled && p_lang == "dot") {
+        p_livePreview = p_inplacePreview = true;
+    } else if (m_mermaidEnabled && p_lang == "mermaid") {
+        p_livePreview = true;
+        p_inplacePreview = false;
+    } else if (m_mathjaxEnabled && p_lang == "mathjax") {
+        p_livePreview = false;
+        p_inplacePreview = true;
+    } else {
+        p_livePreview = p_inplacePreview = false;
+    }
 }
 
 void VLivePreviewHelper::updateCodeBlocks(const QVector<VCodeBlock> &p_codeBlocks)
@@ -164,34 +134,42 @@ void VLivePreviewHelper::updateCodeBlocks(const QVector<VCodeBlock> &p_codeBlock
     int lastIndex = m_cbIndex;
     m_cbIndex = -1;
     int cursorBlock = m_editor->textCursorW().block().blockNumber();
-    int idx = 0;
     bool needUpdate = m_livePreviewEnabled;
     bool manualInplacePreview = m_inplacePreviewEnabled;
-    for (auto const & vcb : p_codeBlocks) {
-        if (!isPreviewLang(vcb.m_lang)) {
+    m_codeBlocks.clear();
+
+    for (int i = 0; i < p_codeBlocks.size(); ++i) {
+        const VCodeBlock &vcb = p_codeBlocks[i];
+        bool livePreview = false, inplacePreview = false;
+        checkLang(vcb.m_lang, livePreview, inplacePreview);
+        if (!livePreview && !inplacePreview) {
             continue;
         }
 
+        const QString &text = vcb.m_text;
         bool cached = false;
-        if (idx < m_codeBlocks.size()) {
-            CodeBlockPreviewInfo &cb = m_codeBlocks[idx];
-            if (cb.codeBlock().equalContent(vcb)) {
-                cb.updateNonContent(m_doc, vcb);
-                cached = true;
-            } else {
-                cb.setCodeBlock(vcb);
-            }
-        } else {
-            m_codeBlocks.append(CodeBlockPreviewInfo(vcb));
+
+        m_codeBlocks.append(CodeBlockPreviewInfo(vcb));
+        int idx = m_codeBlocks.size() - 1;
+
+        auto it = m_cache.find(text);
+        if (it != m_cache.end()) {
+            QSharedPointer<CodeBlockImageCacheEntry> &entry = it.value();
+            entry->m_ts = m_timeStamp;
+            cached = true;
+            m_codeBlocks[idx].setImageData(entry->m_imgFormat, entry->m_imgData);
+            m_codeBlocks[idx].updateInplacePreview(m_editor, m_doc, entry->m_image);
         }
 
         if (m_inplacePreviewEnabled
+            && inplacePreview
             && (!cached || !m_codeBlocks[idx].inplacePreviewReady())) {
-            processForInplacePreview(idx);
             manualInplacePreview = false;
+            processForInplacePreview(idx);
         }
 
         if (m_livePreviewEnabled
+            && livePreview
             && vcb.m_startBlock <= cursorBlock
             && vcb.m_endBlock >= cursorBlock) {
             if (lastIndex == idx && cached) {
@@ -200,14 +178,6 @@ void VLivePreviewHelper::updateCodeBlocks(const QVector<VCodeBlock> &p_codeBlock
 
             m_cbIndex = idx;
         }
-
-        ++idx;
-    }
-
-    if (idx == m_codeBlocks.size()) {
-        manualInplacePreview = false;
-    } else {
-        m_codeBlocks.resize(idx);
     }
 
     if (manualInplacePreview) {
@@ -217,6 +187,8 @@ void VLivePreviewHelper::updateCodeBlocks(const QVector<VCodeBlock> &p_codeBlock
     if (needUpdate) {
         updateLivePreview();
     }
+
+    clearObsoleteCache();
 }
 
 void VLivePreviewHelper::handleCursorPositionChanged()
@@ -319,6 +291,7 @@ void VLivePreviewHelper::setLivePreviewEnabled(bool p_enabled)
 
         if (!m_inplacePreviewEnabled) {
             m_codeBlocks.clear();
+            m_cache.clear();
             updateInplacePreview();
         }
     }
@@ -333,6 +306,7 @@ void VLivePreviewHelper::setInplacePreviewEnabled(bool p_enabled)
     m_inplacePreviewEnabled = p_enabled;
     if (!m_inplacePreviewEnabled && !m_livePreviewEnabled) {
         m_codeBlocks.clear();
+        m_cache.clear();
     }
 
     updateInplacePreview();
@@ -371,7 +345,17 @@ void VLivePreviewHelper::localAsyncResultReady(int p_id,
     }
 
     CodeBlockPreviewInfo &cb = m_codeBlocks[idx];
+    const QString &text = cb.codeBlock().m_text;
+
+    QSharedPointer<CodeBlockImageCacheEntry> entry(new CodeBlockImageCacheEntry(p_timeStamp,
+                                                                                p_format,
+                                                                                p_result,
+                                                                                getScaleFactor(cb)));
+    m_cache.insert(text, entry);
+
     cb.setImageData(p_format, p_result);
+    cb.updateInplacePreview(m_editor, m_doc, entry->m_image);
+
     if (livePreview) {
         if (idx != m_cbIndex) {
             return;
@@ -380,8 +364,6 @@ void VLivePreviewHelper::localAsyncResultReady(int p_id,
         m_document->setPreviewContent(lang, p_result);
     } else {
         // Inplace preview.
-        cb.updateInplacePreview(m_editor, m_doc, getScaleFactor(cb));
-
         updateInplacePreview();
     }
 }
@@ -390,7 +372,7 @@ void VLivePreviewHelper::processForInplacePreview(int p_idx)
 {
     CodeBlockPreviewInfo &cb = m_codeBlocks[p_idx];
     const VCodeBlock &vcb = cb.codeBlock();
-    Q_ASSERT(!(cb.hasImageData() || cb.hasImageDataBa()));
+    Q_ASSERT(!cb.hasImageData());
     if (vcb.m_lang == "dot") {
         if (!m_graphvizHelper) {
             m_graphvizHelper = new VGraphvizHelper(this);
@@ -474,7 +456,31 @@ void VLivePreviewHelper::mathjaxPreviewResultReady(int p_identitifer,
     }
 
     CodeBlockPreviewInfo &cb = m_codeBlocks[p_id];
-    cb.setImageDataBa(p_format, p_data);
-    cb.updateInplacePreview(m_editor, m_doc, getScaleFactor(cb));
+    const QString &text = cb.codeBlock().m_text;
+
+    QSharedPointer<CodeBlockImageCacheEntry> entry(new CodeBlockImageCacheEntry(p_timeStamp,
+                                                                                p_format,
+                                                                                p_data,
+                                                                                getScaleFactor(cb)));
+    m_cache.insert(text, entry);
+
+    cb.updateInplacePreview(m_editor, m_doc, entry->m_image);
+
     updateInplacePreview();
 }
+
+void VLivePreviewHelper::clearObsoleteCache()
+{
+    if (m_cache.size() - m_codeBlocks.size() <= CODE_BLOCK_IMAGE_CACHE_SIZE_DIFF) {
+        return;
+    }
+
+    for (auto it = m_cache.begin(); it != m_cache.end();) {
+        if (m_timeStamp - it.value()->m_ts > CODE_BLOCK_IMAGE_CACHE_TIME_DIFF) {
+            it.value().clear();
+            it = m_cache.erase(it);
+        } else {
+            ++it;
+        }
+    }
+}

src/vlivepreviewhelper.h

@@ -21,19 +21,9 @@ public:
 
     explicit CodeBlockPreviewInfo(const VCodeBlock &p_cb);
 
-    void clearImageData()
-    {
-        m_imgData.clear();
-        m_imgDataBa.clear();
-        m_inplacePreview.clear();
-    }
-
-    void updateNonContent(const QTextDocument *p_doc,
-                          const VCodeBlock &p_cb);
-
     void updateInplacePreview(const VEditor *p_editor,
                               const QTextDocument *p_doc,
-                              qreal p_scaleFactor);
+                              const QPixmap &p_image);
 
     VCodeBlock &codeBlock()
     {
@@ -45,13 +35,6 @@ public:
         return m_codeBlock;
     }
 
-    void setCodeBlock(const VCodeBlock &p_cb)
-    {
-        m_codeBlock = p_cb;
-
-        clearImageData();
-    }
-
     bool inplacePreviewReady() const
     {
         return !m_inplacePreview.isNull();
@@ -67,16 +50,6 @@ public:
         return m_imgData;
     }
 
-    bool hasImageDataBa() const
-    {
-        return !m_imgDataBa.isEmpty();
-    }
-
-    const QByteArray &imageDataBa() const
-    {
-        return m_imgDataBa;
-    }
-
     const QString &imageFormat() const
     {
         return m_imgFormat;
@@ -84,22 +57,10 @@ public:
 
     void setImageData(const QString &p_format, const QString &p_data)
     {
-        m_imgDataBa.clear();
-        m_inplacePreview.clear();
-
         m_imgFormat = p_format;
         m_imgData = p_data;
     }
 
-    void setImageDataBa(const QString &p_format, const QByteArray &p_data)
-    {
-        m_imgData.clear();
-        m_inplacePreview.clear();
-
-        m_imgFormat = p_format;
-        m_imgDataBa = p_data;
-    }
-
     const QSharedPointer<VImageToPreview> inplacePreview() const
     {
         return m_inplacePreview;
@@ -116,8 +77,6 @@ private:
 
     QString m_imgData;
 
-    QByteArray m_imgDataBa;
-
     QString m_imgFormat;
 
     QSharedPointer<VImageToPreview> m_inplacePreview;
@@ -161,7 +120,79 @@ private slots:
                                    const QByteArray &p_data);
 
 private:
-    bool isPreviewLang(const QString &p_lang) const;
+    struct CodeBlockImageCacheEntry
+    {
+        #define SCALE_FACTOR_THRESHOLD 1.1
+
+        CodeBlockImageCacheEntry()
+            : m_ts(0)
+        {
+        }
+
+        CodeBlockImageCacheEntry(TimeStamp p_ts,
+                                 const QString &p_format,
+                                 const QByteArray &p_data,
+                                 qreal p_scaleFactor)
+            : m_ts(p_ts)
+        {
+            if (!p_data.isEmpty()) {
+                if (p_scaleFactor < SCALE_FACTOR_THRESHOLD) {
+                    m_image.loadFromData(p_data,
+                                         p_format.toLocal8Bit().data());
+                } else {
+                    QPixmap tmpImg;
+                    tmpImg.loadFromData(p_data,
+                                        p_format.toLocal8Bit().data());
+                    m_image = tmpImg.scaledToWidth(tmpImg.width() * p_scaleFactor,
+                                                   Qt::SmoothTransformation);
+                }
+            }
+        }
+
+        CodeBlockImageCacheEntry(TimeStamp p_ts,
+                                 const QString &p_format,
+                                 const QString &p_data,
+                                 qreal p_scaleFactor)
+            : m_ts(p_ts),
+              m_imgData(p_data),
+              m_imgFormat(p_format)
+        {
+            if (!p_data.isEmpty()) {
+                if (p_scaleFactor < SCALE_FACTOR_THRESHOLD) {
+                    m_image.loadFromData(p_data.toUtf8(),
+                                         p_format.toLocal8Bit().data());
+                } else {
+                    QPixmap tmpImg;
+                    tmpImg.loadFromData(p_data.toUtf8(),
+                                        p_format.toLocal8Bit().data());
+                    m_image = tmpImg.scaledToWidth(tmpImg.width() * p_scaleFactor,
+                                                   Qt::SmoothTransformation);
+                }
+            }
+        }
+
+        bool hasImageData() const
+        {
+            return !m_imgData.isEmpty();
+        }
+
+        bool hasImage() const
+        {
+            return !m_image.isNull();
+        }
+
+        TimeStamp m_ts;
+
+        // For live preview.
+        QString m_imgData;
+        QString m_imgFormat;
+
+        // For in-place preview.
+        QPixmap m_image;
+    };
+
+
+    void checkLang(const QString &p_lang, bool &p_livePreview, bool &p_inplacePreview) const;
 
     // Get image data for this code block for inplace preview.
     void processForInplacePreview(int p_idx);
@@ -171,6 +202,8 @@ private:
 
     qreal getScaleFactor(const CodeBlockPreviewInfo &p_cb);
 
+    void clearObsoleteCache();
+
     // Sorted by m_startBlock in ascending order.
     QVector<CodeBlockPreviewInfo> m_codeBlocks;
 
@@ -206,6 +239,9 @@ private:
     TimeStamp m_timeStamp;
 
     const qreal m_scaleFactor;
+
+    // Indexed by content.
+    QHash<QString, QSharedPointer<CodeBlockImageCacheEntry>> m_cache;
 };
 
 inline bool VLivePreviewHelper::isPreviewEnabled() const

src/vmathjaxinplacepreviewhelper.cpp

@@ -19,32 +19,9 @@ MathjaxBlockPreviewInfo::MathjaxBlockPreviewInfo(const VMathjaxBlock &p_mb)
 {
 }
 
-void MathjaxBlockPreviewInfo::updateNonContent(const QTextDocument *p_doc,
-                                               const VEditor *p_editor,
-                                               const VMathjaxBlock &p_mb)
-{
-    m_mathjaxBlock.updateNonContent(p_mb);
-    if (m_inplacePreview.isNull()) {
-        return;
-    }
-
-    QTextBlock block = p_doc->findBlockByNumber(m_mathjaxBlock.m_blockNumber);
-    if (block.isValid()) {
-        m_inplacePreview->m_startPos = block.position() + m_mathjaxBlock.m_index;
-        m_inplacePreview->m_endPos = m_inplacePreview->m_startPos + m_mathjaxBlock.m_length;
-        m_inplacePreview->m_blockPos = block.position();
-        m_inplacePreview->m_blockNumber = m_mathjaxBlock.m_blockNumber;
-        // Padding may changed.
-        m_inplacePreview->m_padding = VPreviewManager::calculateBlockMargin(block,
-                                                                            p_editor->tabStopWidthW());
-        m_inplacePreview->m_isBlock = m_mathjaxBlock.m_previewedAsBlock;
-    } else {
-        m_inplacePreview.clear();
-    }
-}
-
 void MathjaxBlockPreviewInfo::updateInplacePreview(const VEditor *p_editor,
-                                                   const QTextDocument *p_doc)
+                                                   const QTextDocument *p_doc,
+                                                   const QPixmap &p_image)
 {
     QTextBlock block = p_doc->findBlockByNumber(m_mathjaxBlock.m_blockNumber);
     if (block.isValid()) {
@@ -59,12 +36,7 @@ void MathjaxBlockPreviewInfo::updateInplacePreview(const VEditor *p_editor,
         preview->m_name = QString::number(getImageIndex());
         preview->m_isBlock = m_mathjaxBlock.m_previewedAsBlock;
 
-        if (hasImageDataBa()) {
-            preview->m_image.loadFromData(m_imgDataBa,
-                                                   m_imgFormat.toLocal8Bit().data());
-        } else {
-            preview->m_image = QPixmap();
-        }
+        preview->m_image = p_image;
 
         m_inplacePreview.reset(preview);
     } else {
@@ -133,13 +105,12 @@ void VMathJaxInplacePreviewHelper::updateMathjaxBlocks(const QVector<VMathjaxBlo
             QSharedPointer<MathjaxImageCacheEntry> &entry = it.value();
             entry->m_ts = m_timeStamp;
             cached = true;
-            m_mathjaxBlocks[i].setImageDataBa(entry->m_imgFormat, entry->m_imgDataBa);
-            m_mathjaxBlocks[i].updateInplacePreview(m_editor, m_doc);
+            m_mathjaxBlocks.last().updateInplacePreview(m_editor, m_doc, entry->m_image);
         }
 
-        if (!cached || !m_mathjaxBlocks[i].inplacePreviewReady()) {
+        if (!cached || !m_mathjaxBlocks.last().inplacePreviewReady()) {
             manualUpdate = false;
-            processForInplacePreview(i);
+            processForInplacePreview(m_mathjaxBlocks.size() - 1);
         }
     }
 
@@ -222,14 +193,12 @@ void VMathJaxInplacePreviewHelper::mathjaxPreviewResultReady(int p_identitifer,
     }
 
     MathjaxBlockPreviewInfo &mb = m_mathjaxBlocks[p_id];
-    mb.setImageDataBa(p_format, p_data);
-    mb.updateInplacePreview(m_editor, m_doc);
-
     // Update the cache.
     QSharedPointer<MathjaxImageCacheEntry> entry(new MathjaxImageCacheEntry(p_timeStamp,
                                                                             p_data,
                                                                             p_format));
     m_cache.insert(mb.mathjaxBlock().m_text, entry);
+    mb.updateInplacePreview(m_editor, m_doc, entry->m_image);
 
     updateInplacePreview();
 }

src/vmathjaxinplacepreviewhelper.h

@@ -19,17 +19,9 @@ public:
 
     explicit MathjaxBlockPreviewInfo(const VMathjaxBlock &p_mb);
 
-    void clearImageData()
-    {
-        m_imgDataBa.clear();
-        m_inplacePreview.clear();
-    }
-
-    void updateNonContent(const QTextDocument *p_doc,
-                          const VEditor *p_editor,
-                          const VMathjaxBlock &p_mb);
-
-    void updateInplacePreview(const VEditor *p_editor, const QTextDocument *p_doc);
+    void updateInplacePreview(const VEditor *p_editor,
+                              const QTextDocument *p_doc,
+                              const QPixmap &p_image);
 
     VMathjaxBlock &mathjaxBlock()
     {
@@ -41,29 +33,11 @@ public:
         return m_mathjaxBlock;
     }
 
-    void setMathjaxBlock(const VMathjaxBlock &p_mb)
-    {
-        m_mathjaxBlock = p_mb;
-        clearImageData();
-    }
-
     bool inplacePreviewReady() const
     {
         return !m_inplacePreview.isNull();
     }
 
-    void setImageDataBa(const QString &p_format, const QByteArray &p_data)
-    {
-        m_imgFormat = p_format;
-        m_imgDataBa = p_data;
-        m_inplacePreview.clear();
-    }
-
-    bool hasImageDataBa() const
-    {
-        return !m_imgDataBa.isEmpty();
-    }
-
     const QSharedPointer<VImageToPreview> inplacePreview() const
     {
         return m_inplacePreview;
@@ -78,10 +52,6 @@ private:
 
     VMathjaxBlock m_mathjaxBlock;
 
-    QByteArray m_imgDataBa;
-
-    QString m_imgFormat;
-
     QSharedPointer<VImageToPreview> m_inplacePreview;
 };
 
@@ -124,15 +94,15 @@ private:
         MathjaxImageCacheEntry(TimeStamp p_ts,
                                const QByteArray &p_dataBa,
                                const QString &p_format)
-            : m_ts(p_ts),
-              m_imgDataBa(p_dataBa),
-              m_imgFormat(p_format)
+            : m_ts(p_ts)
         {
+            if (!p_dataBa.isEmpty()) {
+                m_image.loadFromData(p_dataBa, p_format.toLocal8Bit().data());
+            }
         }
 
         TimeStamp m_ts;
-        QByteArray m_imgDataBa;
-        QString m_imgFormat;
+        QPixmap m_image;
     };