SyntaxHighlighter: Add rerun if highlighting was interrupted

Added mechanism of highlighting restart when the previous
highlighting was interrupted.

Change-Id: Ic44c06442fd9f0002fed760472d5d39903e7ef50
Reviewed-by: <github-actions-qt-creator@cristianadam.eu>
Reviewed-by: David Schulz <david.schulz@qt.io>

4 files changed, 136 insertions, 29 deletions

diff --git a/src/plugins/texteditor/syntaxhighlighter.cpp b/src/plugins/texteditor/syntaxhighlighter.cpp
index 34f4b1c7772..f7db190852d 100644
--- a/src/plugins/texteditor/syntaxhighlighter.cpp
+++ b/src/plugins/texteditor/syntaxhighlighter.cpp
@@ -206,8 +206,11 @@ void SyntaxHighlighterPrivate::reformatBlocks(int from, int charsRemoved, int ch
     vecRes << resStart;
 
     while (block.isValid() && (block.position() < endPosition || forceHighlightOfNextBlock)) {
-        if (QThread::currentThread()->isInterruptionRequested())
-            break;
+        if (QThread::currentThread()->isInterruptionRequested() || q->isInterrupted()) {
+            inReformatBlocks = false;
+            emit q->resultsReady({});
+            return;
+        }
 
         const int stateBeforeHighlight = block.userState();
 
@@ -767,9 +770,7 @@ void SyntaxHighlighter::setExtraFormats(const QTextBlock &block,
     res.m_formatRanges = block.layout()->formats();
     res.fillByBlock(block);
     res.m_state = SyntaxHighlighter::State::Extras;
-    SyntaxHighlighter::Result resDone;
-    resDone.m_state = SyntaxHighlighter::State::Done;
-    emit resultsReady({res, resDone});
+    emit resultsReady({std::move(res)});
 
     document()->markContentsDirty(block.position(), blockLength - 1);
     d->inReformatBlocks = wasInReformatBlocks;
@@ -796,9 +797,7 @@ void SyntaxHighlighter::clearExtraFormats(const QTextBlock &block)
     res.m_formatRanges = block.layout()->formats();
     res.fillByBlock(block);
     res.m_state = SyntaxHighlighter::State::Extras;
-    SyntaxHighlighter::Result resDone;
-    resDone.m_state = SyntaxHighlighter::State::Done;
-    emit resultsReady({res, resDone});
+    emit resultsReady({std::move(res)});
 
     document()->markContentsDirty(block.position(), blockLength - 1);
     d->inReformatBlocks = wasInReformatBlocks;
diff --git a/src/plugins/texteditor/syntaxhighlighter.h b/src/plugins/texteditor/syntaxhighlighter.h
index 533c628b9cd..6b07d333f33 100644
--- a/src/plugins/texteditor/syntaxhighlighter.h
+++ b/src/plugins/texteditor/syntaxhighlighter.h
@@ -56,15 +56,15 @@ public:
     enum State {
         Start,
         InProgress,
-        Extras,
-        Done
+        Done,
+        Extras
     };
 
     struct Result
     {
         void fillByBlock(const QTextBlock &block)
         {
-            m_blockNumber = block.position();
+            m_blockNumber = block.blockNumber();
             m_userState = block.userState();
 
             TextBlockUserData *userDate = TextDocumentLayout::textUserData(block);
@@ -117,6 +117,8 @@ public:
         State m_state = InProgress;
     };
 
+    void setInterrupted(bool interrupted) { m_interrupted = interrupted; }
+    bool isInterrupted() { return m_interrupted; }
     void setExtraFormats(const QTextBlock &block, const QList<QTextLayout::FormatRange> &formats);
     virtual void setLanguageFeaturesFlags(unsigned int /*flags*/) {}; // needed for CppHighlighting
     virtual void setEnabled(bool /*enabled*/) {}; // needed for DiffAndLogHighlighter
@@ -126,6 +128,7 @@ public slots:
     virtual void rehighlight();
     void rehighlightBlock(const QTextBlock &block);
     void clearExtraFormats(const QTextBlock &block);
+    void reformatBlocks(int from, int charsRemoved, int charsAdded);
     void clearAllExtraFormats();
 
 protected:
@@ -165,10 +168,10 @@ signals:
 
 private:
     void setTextFormatCategories(const QList<std::pair<int, TextStyle>> &categories);
-    void reformatBlocks(int from, int charsRemoved, int charsAdded);
     void delayedRehighlight();
 
     QScopedPointer<SyntaxHighlighterPrivate> d_ptr;
+    std::atomic<bool> m_interrupted = false;
 
 #ifdef WITH_TESTS
     friend class tst_highlighter;
diff --git a/src/plugins/texteditor/syntaxhighlighterrunner.cpp b/src/plugins/texteditor/syntaxhighlighterrunner.cpp
index 228b8668493..1a649af5329 100644
--- a/src/plugins/texteditor/syntaxhighlighterrunner.cpp
+++ b/src/plugins/texteditor/syntaxhighlighterrunner.cpp
@@ -81,7 +81,6 @@ public:
     void setFontSettings(const TextEditor::FontSettings &fontSettings)
     {
         m_highlighter->setFontSettings(fontSettings);
-        rehighlight();
     }
 
     void setDefinitionName(const QString &name)
@@ -98,13 +97,51 @@ public:
 
     void rehighlight() { m_highlighter->rehighlight(); }
 
+    void reformatBlocks(int from, int charsRemoved, int charsAdded)
+    {
+        m_highlighter->reformatBlocks(from, charsRemoved, charsAdded);
+    }
+
+    void setInterrupted(bool interrupted) { m_highlighter->setInterrupted(interrupted); }
+
     SyntaxHighlighter *m_highlighter = nullptr;
     QTextDocument *m_document = nullptr;
+
 signals:
     void resultsReady(const QList<SyntaxHighlighter::Result> &result);
 
 };
 
+void SyntaxHighlighterRunner::HighlightingStatus::notInterrupted(int from,
+                                                                 int charsRemoved,
+                                                                 int charsAdded)
+{
+    m_from = from;
+    m_addedChars = charsAdded;
+    m_removedChars = charsRemoved;
+    m_current = from;
+    m_newFrom = from + m_addedChars;
+    m_interruptionRequested = false;
+}
+
+void SyntaxHighlighterRunner::HighlightingStatus::interrupted(int from,
+                                                              int charsRemoved,
+                                                              int charsAdded)
+{
+    m_newFrom = std::min(m_newFrom, from);
+    m_newFrom = std::min(m_current, m_newFrom);
+    m_removedChars += charsRemoved;
+    m_addedChars += charsAdded;
+    m_interruptionRequested = true;
+}
+
+void SyntaxHighlighterRunner::HighlightingStatus::applyNewFrom()
+{
+    m_from = m_newFrom;
+    m_current = m_newFrom;
+    m_interruptionRequested = false;
+}
+
 SyntaxHighlighterRunner::SyntaxHighlighterRunner(SyntaxHighlighter *highlighter,
                                                  QTextDocument *document,
                                                  bool async)
@@ -124,8 +161,8 @@ SyntaxHighlighterRunner::SyntaxHighlighterRunner(SyntaxHighlighter *highlighter,
                 this,
                 &SyntaxHighlighterRunner::applyFormatRanges);
 
-        changeDocument(0, 0, document->characterCount());
-        connect(document,
+        changeDocument(0, 0, m_document->characterCount());
+        connect(m_document,
                 &QTextDocument::contentsChange,
                 this,
                 &SyntaxHighlighterRunner::changeDocument);
@@ -136,10 +173,15 @@ SyntaxHighlighterRunner::SyntaxHighlighterRunner(SyntaxHighlighter *highlighter,
                 &SyntaxHighlighterRunnerPrivate::resultsReady,
                 this,
                 [this](const QList<SyntaxHighlighter::Result> &result) {
+                    if (result.size() == 1
+                        && result.at(0).m_state == SyntaxHighlighter::State::Extras)
+                        return;
+
                     auto done = std::find_if(result.cbegin(),
                                              result.cend(),
                                              [](const SyntaxHighlighter::Result &res) {
-                                                 return res.m_state == SyntaxHighlighter::State::Done;
+                                                 return res.m_state
+                                                        == SyntaxHighlighter::State::Done;
                                              });
                     if (done != result.cend()) {
                         m_syntaxInfoUpdated = SyntaxHighlighter::State::Done;
@@ -168,6 +210,34 @@ void SyntaxHighlighterRunner::applyFormatRanges(const QList<SyntaxHighlighter::R
     if (m_document == nullptr)
         return;
 
+    if (m_highlightingStatus.m_interruptionRequested) {
+        d->setInterrupted(false);
+        m_highlightingStatus.applyNewFrom();
+        reformatBlocks(m_highlightingStatus.m_newFrom,
+                       m_highlightingStatus.m_removedChars,
+                       m_highlightingStatus.m_addedChars);
+        return;
+    }
+
+    auto processResult = [this](SyntaxHighlighter::Result result, QTextBlock docBlock) {
+        if (!docBlock.isValid())
+            return;
+
+        result.copyToBlock(docBlock);
+        m_highlightingStatus.m_current = docBlock.position() + docBlock.length() - 1;
+
+        if (result.m_formatRanges != docBlock.layout()->formats()) {
+            docBlock.layout()->setFormats(result.m_formatRanges);
+            m_document->markContentsDirty(docBlock.position(), docBlock.length());
+        }
+    };
+
+    if (results.size() == 1 && results.at(0).m_state == SyntaxHighlighter::State::Extras) {
+        QTextBlock docBlock = m_document->findBlockByNumber(results.at(0).m_blockNumber);
+        processResult(results.at(0), docBlock);
+        return;
+    }
+
     for (const SyntaxHighlighter::Result &result : results) {
         m_syntaxInfoUpdated = result.m_state;
         if (m_syntaxInfoUpdated == SyntaxHighlighter::State::Start) {
@@ -180,25 +250,18 @@ void SyntaxHighlighterRunner::applyFormatRanges(const QList<SyntaxHighlighter::R
             return;
         }
 
-        QTextBlock docBlock = m_document->findBlock(result.m_blockNumber);
-        if (!docBlock.isValid())
-            return;
-
-        result.copyToBlock(docBlock);
-
-        if (result.m_formatRanges != docBlock.layout()->formats()) {
-            docBlock.layout()->setFormats(result.m_formatRanges);
-            m_document->markContentsDirty(docBlock.position(), docBlock.length());
-        }
-        if (m_syntaxInfoUpdated != SyntaxHighlighter::State::Extras)
-            m_foldValidator.process(docBlock);
+        QTextBlock docBlock = m_document->findBlockByNumber(result.m_blockNumber);
+        processResult(result, docBlock);
+        m_foldValidator.process(docBlock);
     }
 }
 
 void SyntaxHighlighterRunner::changeDocument(int from, int charsRemoved, int charsAdded)
 {
     QTC_ASSERT(m_document, return);
+    SyntaxHighlighter::State prevSyntaxInfoUpdated = m_syntaxInfoUpdated;
     m_syntaxInfoUpdated = SyntaxHighlighter::State::InProgress;
+
     QMap<int, BlockPreeditData> blocksPreedit;
     QTextBlock block = m_document->findBlock(from);
     const QTextBlock endBlock = m_document->findBlock(from + charsAdded);
@@ -213,6 +276,14 @@ void SyntaxHighlighterRunner::changeDocument(int from, int charsRemoved, int cha
     QMetaObject::invokeMethod(d, [this, from, charsRemoved, text, blocksPreedit] {
         d->changeDocument(from, charsRemoved, text, blocksPreedit);
     });
+
+    if (prevSyntaxInfoUpdated == SyntaxHighlighter::State::InProgress) {
+        m_highlightingStatus.interrupted(from, charsRemoved, charsAdded);
+        d->setInterrupted(true);
+    } else {
+        m_highlightingStatus.notInterrupted(from, charsRemoved, charsAdded);
+        d->setInterrupted(false);
+    }
 }
 
 bool SyntaxHighlighterRunner::useGenericHighlighter() const
@@ -239,6 +310,7 @@ void SyntaxHighlighterRunner::clearAllExtraFormats()
 void SyntaxHighlighterRunner::setFontSettings(const TextEditor::FontSettings &fontSettings)
 {
     QMetaObject::invokeMethod(d, [this, fontSettings] { d->setFontSettings(fontSettings); });
+    rehighlight();
 }
 
 void SyntaxHighlighterRunner::setLanguageFeaturesFlags(unsigned int flags)
@@ -253,7 +325,24 @@ void SyntaxHighlighterRunner::setEnabled(bool enabled)
 
 void SyntaxHighlighterRunner::rehighlight()
 {
-    QMetaObject::invokeMethod(d, [this] { d->rehighlight(); });
+    if (m_syntaxInfoUpdated == SyntaxHighlighter::State::InProgress) {
+        m_highlightingStatus.interrupted(0, 0, m_document->characterCount());
+        d->setInterrupted(true);
+    } else {
+        m_highlightingStatus.notInterrupted(0, 0, m_document->characterCount());
+        d->setInterrupted(false);
+        QMetaObject::invokeMethod(d, [this] { d->rehighlight(); });
+    }
+}
+
+
+void SyntaxHighlighterRunner::reformatBlocks(int from, int charsRemoved, int charsAdded)
+{
+    QMetaObject::invokeMethod(
+        d,
+        [this, from, charsRemoved, charsAdded] {
+            d->reformatBlocks(from, charsRemoved, charsAdded);
+        });
 }
 
 QString SyntaxHighlighterRunner::definitionName()
diff --git a/src/plugins/texteditor/syntaxhighlighterrunner.h b/src/plugins/texteditor/syntaxhighlighterrunner.h
index 5540bd666a9..16b7c1535c8 100644
--- a/src/plugins/texteditor/syntaxhighlighterrunner.h
+++ b/src/plugins/texteditor/syntaxhighlighterrunner.h
@@ -34,6 +34,7 @@ public:
     void setLanguageFeaturesFlags(unsigned int flags);
     void setEnabled(bool enabled);
     void rehighlight();
+    void reformatBlocks(int from, int charsRemoved, int charsAdded);
 
     QString definitionName();
     void setDefinitionName(const QString &name);
@@ -53,6 +54,21 @@ private:
     SyntaxHighlighterRunnerPrivate *d;
     QPointer<QTextDocument> m_document = nullptr;
     SyntaxHighlighter::State m_syntaxInfoUpdated = SyntaxHighlighter::State::Done;
+
+    struct HighlightingStatus
+    {
+        int m_from = 0;
+        int m_addedChars = 0;
+        int m_current = 0;
+        int m_removedChars = 0;
+        int m_newFrom = 0;
+        bool m_interruptionRequested = false;
+
+        void notInterrupted(int from, int charsRemoved, int charsAdded);
+        void interrupted(int from, int charsRemoved, int charsAdded);
+        void applyNewFrom();
+    } m_highlightingStatus;
+
     bool m_useGenericHighlighter = false;
     QString m_definitionName;
     std::optional<QThread> m_thread;