ClassView: Move the GUI related code out of Parser

Don't create QStandardItem objects inside the non-gui thread,
as it was in case of requestCurrentState() which is always
called in parser's thread. As a result of parsing send a root's
ParserTreeItem::ConstPtr now instead. Store the generated
root inside Manager instead of inside Parser. Remove rootItemLocker
as it's not needed now anymore. Move the implementation of
canFetchMore(), fetchMore() and hasChildren() into Manager class.

Now all the API of Parser class is used only in parser's thread
(with the exception of constructor and destructor).

Task-number: QTCREATORBUG-25317
Change-Id: I2b3c49918bf58266e6bea8acf65c975e19f7d9cb
Reviewed-by: Christian Kandeler <christian.kandeler@qt.io>

src/plugins/classview/classviewmanager.cpp

@@ -96,6 +96,8 @@ public:
     //! separate thread for the parser
     QThread parserThread;
 
+    ParserTreeItem::ConstPtr m_root;
+
     //! Internal manager state. \sa Manager::state
     bool state = false;
 
@@ -135,28 +137,68 @@ Manager *Manager::instance()
     return managerInstance;
 }
 
+/*!
+    Returns the internal tree item for \a item. \a skipRoot skips the root
+    item.
+*/
+ParserTreeItem::ConstPtr Manager::findItemByRoot(const QStandardItem *item, bool skipRoot) const
+{
+    if (!item)
+        return ParserTreeItem::ConstPtr();
+
+    // go item by item to the root
+    QList<const QStandardItem *> uiList;
+    const QStandardItem *cur = item;
+    while (cur) {
+        uiList.append(cur);
+        cur = cur->parent();
+    }
+
+    if (skipRoot && uiList.count() > 0)
+        uiList.removeLast();
+
+    ParserTreeItem::ConstPtr internal = d->m_root;
+    while (uiList.count() > 0) {
+        cur = uiList.last();
+        uiList.removeLast();
+        const SymbolInformation &inf = Internal::symbolInformationFromItem(cur);
+        internal = internal->child(inf);
+        if (internal.isNull())
+            break;
+    }
+
+    return internal;
+}
+
 /*!
     Checks \a item for lazy data population of a QStandardItemModel.
 */
-
 bool Manager::canFetchMore(QStandardItem *item, bool skipRoot) const
 {
-    return d->parser.canFetchMore(item, skipRoot);
+    ParserTreeItem::ConstPtr ptr = findItemByRoot(item, skipRoot);
+    if (ptr.isNull())
+        return false;
+    return ptr->canFetchMore(item);
 }
 
 /*!
     Checks \a item for lazy data population of a QStandardItemModel.
     \a skipRoot item is needed for the manual update, call not from model.
 */
-
 void Manager::fetchMore(QStandardItem *item, bool skipRoot)
 {
-    d->parser.fetchMore(item, skipRoot);
+    ParserTreeItem::ConstPtr ptr = findItemByRoot(item, skipRoot);
+    if (ptr.isNull())
+        return;
+    ptr->fetchMore(item);
 }
 
 bool Manager::hasChildren(QStandardItem *item) const
 {
-    return d->parser.hasChildren(item);
+    ParserTreeItem::ConstPtr ptr = findItemByRoot(item);
+    if (ptr.isNull())
+        return false;
+    return ptr->childCount() != 0;
 }
 
 void Manager::initialize()
@@ -195,15 +237,16 @@ void Manager::initialize()
         resetParser();
     });
 
-    // translate data update from the parser to listeners
-    connect(&d->parser, &Parser::treeDataUpdate,
-            this, [this](QSharedPointer<QStandardItem> result) {
-        // do nothing if Manager is disabled
+    connect(&d->parser, &Parser::treeRegenerated,
+            this, [this](const ParserTreeItem::ConstPtr &root) {
+        d->m_root = root;
+
         if (!state())
             return;
 
-        emit treeDataUpdate(result);
-
+        QSharedPointer<QStandardItem> rootItem(new QStandardItem());
+        d->m_root->convertTo(rootItem.data());
+        emit treeDataUpdate(rootItem);
     }, Qt::QueuedConnection);
 
     // connect to the cpp model manager for signals about document updates

src/plugins/classview/classviewmanager.h

@@ -30,9 +30,10 @@
 #include <QStandardItem>
 
 #include <cplusplus/CppDocument.h>
-
 #include <utils/id.h>
 
+#include "classviewparsertreeitem.h"
+
 namespace ClassView {
 namespace Internal {
 
@@ -59,6 +60,7 @@ signals:
     void treeDataUpdate(QSharedPointer<QStandardItem> result);
 
 private:
+    ParserTreeItem::ConstPtr findItemByRoot(const QStandardItem *item, bool skipRoot = false) const;
     void onProjectListChanged();
     void resetParser();
 

src/plugins/classview/classviewparser.cpp

@@ -111,12 +111,6 @@ public:
     //! List for files which has to be parsed
     QSet<QString> fileList;
 
-    //! Root item read write lock
-    QReadWriteLock rootItemLocker;
-
-    //! Parsed root item
-    ParserTreeItem::ConstPtr rootItem;
-
     //! Flat mode
     bool flatMode = false;
 };
@@ -151,39 +145,6 @@ Parser::~Parser()
     delete d;
 }
 
-/*!
-    Checks \a item for lazy data population of a QStandardItemModel.
-*/
-
-bool Parser::canFetchMore(QStandardItem *item, bool skipRoot) const
-{
-    ParserTreeItem::ConstPtr ptr = findItemByRoot(item, skipRoot);
-    if (ptr.isNull())
-        return false;
-    return ptr->canFetchMore(item);
-}
-
-/*!
-    Checks \a item for lazy data population of a QStandardItemModel.
-    \a skipRoot skips the root item.
-*/
-
-void Parser::fetchMore(QStandardItem *item, bool skipRoot) const
-{
-    ParserTreeItem::ConstPtr ptr = findItemByRoot(item, skipRoot);
-    if (ptr.isNull())
-        return;
-    ptr->fetchMore(item);
-}
-
-bool Parser::hasChildren(QStandardItem *item) const
-{
-    ParserTreeItem::ConstPtr ptr = findItemByRoot(item);
-    if (ptr.isNull())
-        return false;
-    return ptr->childCount() != 0;
-}
-
 /*!
     Switches to flat mode (without subprojects) if \a flat returns \c true.
 */
@@ -206,45 +167,6 @@ void Parser::aboutToShutdown()
     d->timer.stop();
 }
 
-/*!
-    Returns the internal tree item for \a item. \a skipRoot skips the root
-    item.
-*/
-
-ParserTreeItem::ConstPtr Parser::findItemByRoot(const QStandardItem *item, bool skipRoot) const
-{
-    if (!item)
-        return ParserTreeItem::ConstPtr();
-
-    // go item by item to the root
-    QList<const QStandardItem *> uiList;
-    const QStandardItem *cur = item;
-    while (cur) {
-        uiList.append(cur);
-        cur = cur->parent();
-    }
-
-    if (skipRoot && uiList.count() > 0)
-        uiList.removeLast();
-
-    ParserTreeItem::ConstPtr internal;
-    {
-        QReadLocker locker(&d->rootItemLocker);
-        internal = d->rootItem;
-    }
-
-    while (uiList.count() > 0) {
-        cur = uiList.last();
-        uiList.removeLast();
-        const SymbolInformation &inf = Internal::symbolInformationFromItem(cur);
-        internal = internal->child(inf);
-        if (internal.isNull())
-            break;
-    }
-
-    return internal;
-}
-
 /*!
     Parses the class and produces a new tree.
 
@@ -486,16 +408,7 @@ void Parser::requestCurrentState()
     d->timer.stop();
 
     // TODO: we need to have a fresh SessionManager data here, which we could pass to parse()
-    const ParserTreeItem::ConstPtr newRoot = parse();
-    {
-        QWriteLocker locker(&d->rootItemLocker);
-        d->rootItem = newRoot;
-    }
-
-    QSharedPointer<QStandardItem> std(new QStandardItem());
-    d->rootItem->convertTo(std.data());
-
-    emit treeDataUpdate(std);
+    emit treeRegenerated(parse());
 }
 
 // TODO: don't use Project class in this thread

src/plugins/classview/classviewparser.h

@@ -52,11 +52,6 @@ public:
     explicit Parser(QObject *parent = nullptr);
     ~Parser() override;
 
-    // TODO: below three methods are called directly from different thread
-    bool canFetchMore(QStandardItem *item, bool skipRoot = false) const;
-    void fetchMore(QStandardItem *item, bool skipRoot = false) const;
-    bool hasChildren(QStandardItem *item) const;
-
     void requestCurrentState();
     void removeFiles(const QStringList &fileList);
     void resetDataToCurrentState();
@@ -65,7 +60,7 @@ public:
     void aboutToShutdown();
 
 signals:
-    void treeDataUpdate(QSharedPointer<QStandardItem> result);
+    void treeRegenerated(const ParserTreeItem::ConstPtr &root);
 
 private:
     void setFileList(const QStringList &fileList);
@@ -77,7 +72,6 @@ private:
     ParserTreeItem::Ptr getCachedOrParseProjectTree(const QStringList &fileList,
                                                     const QString &projectId);
     ParserTreeItem::ConstPtr parse();
-    ParserTreeItem::ConstPtr findItemByRoot(const QStandardItem *item, bool skipRoot = false) const;
 
     QStringList getAllFiles(const ProjectExplorer::Project *project);
     ParserTreeItem::Ptr addFlatTree(const ProjectExplorer::Project *project);

src/plugins/classview/classviewparsertreeitem.h

@@ -75,3 +75,5 @@ private:
 
 } // namespace Internal
 } // namespace ClassView
+
+Q_DECLARE_METATYPE(ClassView::Internal::ParserTreeItem::ConstPtr)