CppTools: Apply 'static' pattern to StringTable

This also fixes a crash on loading (some?) projects introduced
in 577bf7c08a.

Change-Id: Ie35d466fa3b84b183118fe93f55393a4c59755de
Reviewed-by: Nikolai Kosjar <nikolai.kosjar@qt.io>

13 files changed, 97 insertions, 105 deletions

diff --git a/src/plugins/cpptools/builtinindexingsupport.cpp b/src/plugins/cpptools/builtinindexingsupport.cpp
index d51ba79e1a..f14d091485 100644
--- a/src/plugins/cpptools/builtinindexingsupport.cpp
+++ b/src/plugins/cpptools/builtinindexingsupport.cpp
@@ -277,7 +277,7 @@ public:
         future.setProgressValue(0);
         int progress = 0;
 
-        SearchSymbols search(CppToolsPlugin::stringTable());
+        SearchSymbols search;
         search.setSymbolsToSearchFor(m_parameters.types);
         CPlusPlus::Snapshot::const_iterator it = m_snapshot.begin();
 
diff --git a/src/plugins/cpptools/cppcurrentdocumentfilter.cpp b/src/plugins/cpptools/cppcurrentdocumentfilter.cpp
index baace1529f..c1a0b9f5e4 100644
--- a/src/plugins/cpptools/cppcurrentdocumentfilter.cpp
+++ b/src/plugins/cpptools/cppcurrentdocumentfilter.cpp
@@ -37,10 +37,8 @@
 using namespace CppTools::Internal;
 using namespace CPlusPlus;
 
-CppCurrentDocumentFilter::CppCurrentDocumentFilter(CppTools::CppModelManager *manager,
-                                                   StringTable &stringTable)
+CppCurrentDocumentFilter::CppCurrentDocumentFilter(CppTools::CppModelManager *manager)
     : m_modelManager(manager)
-    , search(stringTable)
 {
     setId(Constants::CURRENT_DOCUMENT_FILTER_ID);
     setDisplayName(Constants::CURRENT_DOCUMENT_FILTER_DISPLAY_NAME);
diff --git a/src/plugins/cpptools/cppcurrentdocumentfilter.h b/src/plugins/cpptools/cppcurrentdocumentfilter.h
index d3452e26e1..147bb66309 100644
--- a/src/plugins/cpptools/cppcurrentdocumentfilter.h
+++ b/src/plugins/cpptools/cppcurrentdocumentfilter.h
@@ -42,8 +42,7 @@ class CppCurrentDocumentFilter : public  Core::ILocatorFilter
     Q_OBJECT
 
 public:
-    explicit CppCurrentDocumentFilter(CppModelManager *manager,
-                                      StringTable &stringTable);
+    explicit CppCurrentDocumentFilter(CppModelManager *manager);
     ~CppCurrentDocumentFilter() {}
 
     QList<Core::LocatorFilterEntry> matchesFor(QFutureInterface<Core::LocatorFilterEntry> &future,
diff --git a/src/plugins/cpptools/cpplocatordata.cpp b/src/plugins/cpptools/cpplocatordata.cpp
index df80645f69..d736736191 100644
--- a/src/plugins/cpptools/cpplocatordata.cpp
+++ b/src/plugins/cpptools/cpplocatordata.cpp
@@ -24,7 +24,7 @@
 ****************************************************************************/
 
 #include "cpplocatordata.h"
-#include "cpptoolsplugin.h"
+#include "stringtable.h"
 
 using namespace CppTools;
 using namespace CppTools::Internal;
@@ -32,9 +32,7 @@ using namespace CppTools::Internal;
 enum { MaxPendingDocuments = 10 };
 
 CppLocatorData::CppLocatorData()
-    : m_strings(&CppToolsPlugin::stringTable())
-    , m_search(CppToolsPlugin::stringTable())
-    , m_pendingDocumentsMutex(QMutex::Recursive)
+    : m_pendingDocumentsMutex(QMutex::Recursive)
 {
     m_search.setSymbolsToSearchFor(SymbolSearcher::Enums |
                                    SymbolSearcher::Classes |
@@ -79,7 +77,7 @@ void CppLocatorData::onAboutToRemoveFiles(const QStringList &files)
         }
     }
 
-    m_strings->scheduleGC();
+    StringTable::scheduleGC();
     flushPendingDocument(false);
 }
 
@@ -93,7 +91,7 @@ void CppLocatorData::flushPendingDocument(bool force) const
         return;
 
     foreach (CPlusPlus::Document::Ptr doc, m_pendingDocuments)
-        m_infosByFile.insert(findOrInsertFilePath(doc->fileName()), m_search(doc));
+        m_infosByFile.insert(StringTable::insert(doc->fileName()), m_search(doc));
 
     m_pendingDocuments.clear();
     m_pendingDocuments.reserve(MaxPendingDocuments);
diff --git a/src/plugins/cpptools/cpplocatordata.h b/src/plugins/cpptools/cpplocatordata.h
index 2a835b46df..467646776e 100644
--- a/src/plugins/cpptools/cpplocatordata.h
+++ b/src/plugins/cpptools/cpplocatordata.h
@@ -28,7 +28,6 @@
 #include "cpptools_global.h"
 #include "cppmodelmanager.h"
 #include "searchsymbols.h"
-#include "stringtable.h"
 
 #include <cplusplus/CppDocument.h>
 
@@ -64,12 +63,6 @@ private:
     void flushPendingDocument(bool force) const;
     QList<IndexItem::Ptr> allIndexItems(const QHash<QString, QList<IndexItem::Ptr>> &items) const;
 
-    QString findOrInsertFilePath(const QString &path) const
-    { return m_strings->insert(path); }
-
-private:
-    Internal::StringTable *m_strings = nullptr; // Used to avoid QString duplication
-
     mutable SearchSymbols m_search;
     mutable QHash<QString, IndexItem::Ptr> m_infosByFile;
 
diff --git a/src/plugins/cpptools/cppmodelmanager.cpp b/src/plugins/cpptools/cppmodelmanager.cpp
index 5ad004b76c..508bf76be4 100644
--- a/src/plugins/cpptools/cppmodelmanager.cpp
+++ b/src/plugins/cpptools/cppmodelmanager.cpp
@@ -41,10 +41,11 @@
 #include "cpprefactoringchanges.h"
 #include "cpprefactoringengine.h"
 #include "cppsourceprocessor.h"
-#include "cpptoolsconstants.h"
 #include "cpptoolsplugin.h"
+#include "cpptoolsconstants.h"
 #include "cpptoolsreuse.h"
 #include "editordocumenthandle.h"
+#include "stringtable.h"
 #include "symbolfinder.h"
 #include "symbolsfindfilter.h"
 #include "followsymbolinterface.h"
@@ -442,16 +443,15 @@ void CppModelManager::resetFilters()
     setCurrentDocumentFilter();
 }
 
-void CppModelManager::createCppModelManager(Internal::CppToolsPlugin *parent,
-                                            Internal::StringTable &stringTable)
+void CppModelManager::createCppModelManager(Internal::CppToolsPlugin *parent)
 {
     QTC_ASSERT(!m_instance, return;);
     m_instance = new CppModelManager();
-    m_instance->initCppTools(stringTable);
+    m_instance->initCppTools();
     m_instance->setParent(parent);
 }
 
-void CppModelManager::initCppTools(Internal::StringTable &stringTable)
+void CppModelManager::initCppTools()
 {
     // Objects
     connect(Core::VcsManager::instance(), &Core::VcsManager::repositoryChanged,
@@ -477,7 +477,7 @@ void CppModelManager::initCppTools(Internal::StringTable &stringTable)
     setFunctionsFilter(std::make_unique<CppFunctionsFilter>(&d->m_locatorData));
     setSymbolsFindFilter(std::make_unique<SymbolsFindFilter>(this));
     setCurrentDocumentFilter(
-                std::make_unique<Internal::CppCurrentDocumentFilter>(this, stringTable));
+                std::make_unique<Internal::CppCurrentDocumentFilter>(this));
 }
 
 void CppModelManager::initializeBuiltinModelManagerSupport()
diff --git a/src/plugins/cpptools/cppmodelmanager.h b/src/plugins/cpptools/cppmodelmanager.h
index 17b2cca3ec..7bd7ce157a 100644
--- a/src/plugins/cpptools/cppmodelmanager.h
+++ b/src/plugins/cpptools/cppmodelmanager.h
@@ -31,7 +31,6 @@
 #include "projectinfo.h"
 #include "projectpart.h"
 #include "projectpartheaderpath.h"
-#include "stringtable.h"
 
 #include <cplusplus/cppmodelmanagerbase.h>
 #include <coreplugin/find/ifindfilter.h>
@@ -94,8 +93,7 @@ public:
     ~CppModelManager();
 
     static CppModelManager *instance();
-    static void createCppModelManager(Internal::CppToolsPlugin *parent,
-                                      Internal::StringTable &stringTable);
+    static void createCppModelManager(Internal::CppToolsPlugin *parent);
 
      // Documented in source file.
      enum ProgressNotificationMode {
@@ -273,7 +271,7 @@ private:
     ProjectExplorer::Macros internalDefinedMacros() const;
 
     void dumpModelManagerConfiguration(const QString &logFileId);
-    void initCppTools(Internal::StringTable &stringTable);
+    void initCppTools();
     void resetFilters();
 
 private:
diff --git a/src/plugins/cpptools/cpptoolsplugin.cpp b/src/plugins/cpptools/cpptoolsplugin.cpp
index 3cd62a7778..152ecba8aa 100644
--- a/src/plugins/cpptools/cpptoolsplugin.cpp
+++ b/src/plugins/cpptools/cpptoolsplugin.cpp
@@ -35,6 +35,7 @@
 #include "cppprojectfile.h"
 #include "cpptoolsbridge.h"
 #include "projectinfo.h"
+#include "stringtable.h"
 #include "cpptoolsbridgeqtcreatorimplementation.h"
 
 #include <coreplugin/actionmanager/actioncontainer.h>
@@ -74,13 +75,14 @@ enum { debug = 0 };
 static CppToolsPlugin *m_instance = nullptr;
 static QHash<QString, QString> m_headerSourceMapping;
 
-class CppToolsPluginPluginPrivate
+class CppToolsPluginPrivate
 {
 public:
-    CppToolsPluginPluginPrivate()
+    CppToolsPluginPrivate()
         : m_codeModelSettings(new CppCodeModelSettings)
     {
-        CppModelManager::createCppModelManager(m_instance, m_stringTable);
+        StringTable::initialize();
+        CppModelManager::createCppModelManager(m_instance);
         m_settings = new CppToolsSettings(m_instance); // force registration of cpp tools settings
         m_codeModelSettings->fromSettings(ICore::settings());
         m_cppFileSettingsPage = new CppFileSettingsPage(m_instance->m_fileSettings);
@@ -88,8 +90,9 @@ public:
         m_cppCodeStyleSettingsPage = new CppCodeStyleSettingsPage;
     }
 
-    ~CppToolsPluginPluginPrivate()
+    ~CppToolsPluginPrivate()
     {
+        StringTable::destroy();
         delete m_cppFileSettingsPage;
         delete m_cppCodeModelSettingsPage;
         delete m_cppCodeStyleSettingsPage;
@@ -97,7 +100,6 @@ public:
 
     QSharedPointer<CppCodeModelSettings> m_codeModelSettings;
     CppToolsSettings *m_settings = nullptr;
-    StringTable m_stringTable;
     CppFileSettingsPage *m_cppFileSettingsPage = nullptr;
     CppCodeModelSettingsPage *m_cppCodeModelSettingsPage = nullptr;
     CppCodeStyleSettingsPage *m_cppCodeStyleSettingsPage = nullptr;
@@ -163,7 +165,7 @@ bool CppToolsPlugin::initialize(const QStringList &arguments, QString *error)
     Q_UNUSED(arguments)
     Q_UNUSED(error)
 
-    d = new CppToolsPluginPluginPrivate;
+    d = new CppToolsPluginPrivate;
 
     JsExpander::registerQObjectForJs(QLatin1String("Cpp"), new CppToolsJsExtension);
 
@@ -219,11 +221,6 @@ QSharedPointer<CppCodeModelSettings> CppToolsPlugin::codeModelSettings() const
     return d->m_codeModelSettings;
 }
 
-StringTable &CppToolsPlugin::stringTable()
-{
-    return m_instance->d->m_stringTable;
-}
-
 void CppToolsPlugin::switchHeaderSource()
 {
     CppTools::switchHeaderSource();
diff --git a/src/plugins/cpptools/cpptoolsplugin.h b/src/plugins/cpptools/cpptoolsplugin.h
index 077fddf56d..25ae97f1c8 100644
--- a/src/plugins/cpptools/cpptoolsplugin.h
+++ b/src/plugins/cpptools/cpptoolsplugin.h
@@ -26,7 +26,6 @@
 #pragma once
 
 #include "cpptools_global.h"
-#include "stringtable.h"
 
 #include <projectexplorer/projectexplorer.h>
 
@@ -47,7 +46,7 @@ class CppCodeModelSettings;
 namespace Internal {
 
 struct CppFileSettings;
-class CppToolsPluginPluginPrivate;
+class CppToolsPluginPrivate;
 
 class CppToolsPlugin : public ExtensionSystem::IPlugin
 {
@@ -72,8 +71,6 @@ public:
 
     QSharedPointer<CppCodeModelSettings> codeModelSettings() const;
 
-    static StringTable &stringTable();
-
 public slots:
     void switchHeaderSource();
     void switchHeaderSourceInNextSplit();
@@ -180,8 +177,8 @@ private slots:
 #endif
 
 private:
-    friend class CppToolsPluginPluginPrivate;
-    CppToolsPluginPluginPrivate *d = nullptr;
+    friend class CppToolsPluginPrivate;
+    CppToolsPluginPrivate *d = nullptr;
     QSharedPointer<CppFileSettings> m_fileSettings;
 };
 
diff --git a/src/plugins/cpptools/searchsymbols.cpp b/src/plugins/cpptools/searchsymbols.cpp
index 68988d099c..9ec44a3ba7 100644
--- a/src/plugins/cpptools/searchsymbols.cpp
+++ b/src/plugins/cpptools/searchsymbols.cpp
@@ -24,6 +24,7 @@
 ****************************************************************************/
 
 #include "searchsymbols.h"
+#include "stringtable.h"
 
 #include <cplusplus/Icons.h>
 #include <cplusplus/LookupContext.h>
@@ -45,9 +46,8 @@ SearchSymbols::SymbolTypes SearchSymbols::AllTypes =
         | SymbolSearcher::Enums
         | SymbolSearcher::Declarations;
 
-SearchSymbols::SearchSymbols(Internal::StringTable &stringTable)
-    : strings(stringTable)
-    , symbolsToSearchFor(SymbolSearcher::Classes | SymbolSearcher::Functions | SymbolSearcher::Enums)
+SearchSymbols::SearchSymbols()
+    : symbolsToSearchFor(SymbolSearcher::Classes | SymbolSearcher::Functions | SymbolSearcher::Enums)
 {
 }
 
@@ -58,7 +58,7 @@ void SearchSymbols::setSymbolsToSearchFor(const SymbolTypes &types)
 
 IndexItem::Ptr SearchSymbols::operator()(Document::Ptr doc, const QString &scope)
 {
-    IndexItem::Ptr root = IndexItem::create(findOrInsert(doc->fileName()), 100);
+    IndexItem::Ptr root = IndexItem::create(Internal::StringTable::insert(doc->fileName()), 100);
 
     { // RAII scope
         ScopedIndexItemPtr parentRaii(_parent, root);
@@ -67,13 +67,13 @@ IndexItem::Ptr SearchSymbols::operator()(Document::Ptr doc, const QString &scope
 
         QTC_ASSERT(_parent, return IndexItem::Ptr());
         QTC_ASSERT(root, return IndexItem::Ptr());
-        QTC_ASSERT(_parent->fileName() == findOrInsert(doc->fileName()),
+        QTC_ASSERT(_parent->fileName() == Internal::StringTable::insert(doc->fileName()),
                    return IndexItem::Ptr());
 
         for (unsigned i = 0, ei = doc->globalSymbolCount(); i != ei; ++i)
             accept(doc->globalSymbolAt(i));
 
-        strings.scheduleGC();
+        Internal::StringTable::scheduleGC();
         m_paths.clear();
     }
 
@@ -294,11 +294,12 @@ IndexItem::Ptr SearchSymbols::addChildItem(const QString &symbolName, const QStr
     }
 
     const QIcon icon = Icons::iconForSymbol(symbol);
-    IndexItem::Ptr newItem = IndexItem::create(findOrInsert(symbolName),
-                                               findOrInsert(symbolType),
-                                               findOrInsert(symbolScope),
+
+    IndexItem::Ptr newItem = IndexItem::create(Internal::StringTable::insert(symbolName),
+                                               Internal::StringTable::insert(symbolType),
+                                               Internal::StringTable::insert(symbolScope),
                                                itemType,
-                                               findOrInsert(path),
+                                               Internal::StringTable::insert(path),
                                                symbol->line(),
                                                symbol->column() - 1, // 1-based vs 0-based column
                                                icon);
diff --git a/src/plugins/cpptools/searchsymbols.h b/src/plugins/cpptools/searchsymbols.h
index 68580d6156..b89b77e03d 100644
--- a/src/plugins/cpptools/searchsymbols.h
+++ b/src/plugins/cpptools/searchsymbols.h
@@ -28,7 +28,6 @@
 #include "cpptools_global.h"
 #include "cppindexingsupport.h"
 #include "indexitem.h"
-#include "stringtable.h"
 
 #include <cplusplus/CppDocument.h>
 #include <cplusplus/Overview.h>
@@ -46,7 +45,7 @@ public:
 
     static SymbolTypes AllTypes;
 
-    SearchSymbols(Internal::StringTable &stringTable);
+    SearchSymbols();
 
     void setSymbolsToSearchFor(const SymbolTypes &types);
 
@@ -98,11 +97,6 @@ private:
     template<class T> void processFunction(T *func);
 
 private:
-    QString findOrInsert(const QString &s)
-    { return strings.insert(s); }
-
-    Internal::StringTable &strings;            // Used to avoid QString duplication
-
     IndexItem::Ptr _parent;
     QString _scope;
     CPlusPlus::Overview overview;
diff --git a/src/plugins/cpptools/stringtable.cpp b/src/plugins/cpptools/stringtable.cpp
index a3bcf443c4..d9d806d239 100644
--- a/src/plugins/cpptools/stringtable.cpp
+++ b/src/plugins/cpptools/stringtable.cpp
@@ -28,8 +28,11 @@
 #include <utils/qtcassert.h>
 
 #include <QDebug>
+#include <QMutex>
+#include <QSet>
 #include <QThreadPool>
 #include <QTime>
+#include <QTimer>
 
 using namespace CppTools::Internal;
 
@@ -37,9 +40,37 @@ enum {
     GCTimeOut = 10 * 1000 // 10 seconds
 };
 
-StringTable::StringTable()
+enum {
+    DebugStringTable = 0
+};
+
+class StringTablePrivate : public QObject
+{
+public:
+    StringTablePrivate();
+
+    QString insert(const QString &string);
+    void startGC() { QThreadPool::globalInstance()->start(&m_gcRunner); }
+    void GC();
+
+    class GCRunner: public QRunnable {
+        StringTablePrivate &m_stringTable;
+
+    public:
+        GCRunner(StringTablePrivate &stringTable): m_stringTable(stringTable) {}
+        virtual void run() { m_stringTable.GC(); }
+    } m_gcRunner;
+
+    mutable QMutex m_lock;
+    QAtomicInt m_stopGCRequested{false};
+    QSet<QString> m_strings;
+    QTimer m_gcCountDown;
+};
+
+static StringTablePrivate *m_instance = nullptr;
+
+StringTablePrivate::StringTablePrivate()
     : m_gcRunner(*this)
-    , m_stopGCRequested(false)
 {
     m_strings.reserve(1000);
 
@@ -48,11 +79,16 @@ StringTable::StringTable()
     m_gcCountDown.setObjectName(QLatin1String("StringTable::m_gcCountDown"));
     m_gcCountDown.setSingleShot(true);
     m_gcCountDown.setInterval(GCTimeOut);
-    connect(&m_gcCountDown, &QTimer::timeout, this, &StringTable::startGC);
+    connect(&m_gcCountDown, &QTimer::timeout, this, &StringTablePrivate::startGC);
 }
 
 QString StringTable::insert(const QString &string)
 {
+    return m_instance->insert(string);
+}
+
+QString StringTablePrivate::insert(const QString &string)
+{
     if (string.isEmpty())
         return string;
 
@@ -70,17 +106,19 @@ QString StringTable::insert(const QString &string)
 
 void StringTable::scheduleGC()
 {
-    QMetaObject::invokeMethod(&m_gcCountDown, "start", Qt::QueuedConnection);
+    QMetaObject::invokeMethod(&m_instance->m_gcCountDown, "start", Qt::QueuedConnection);
 }
 
-void StringTable::startGC()
+void StringTable::initialize()
 {
-    QThreadPool::globalInstance()->start(&m_gcRunner);
+    m_instance = new StringTablePrivate;
 }
 
-enum {
-    DebugStringTable = 0
-};
+void StringTable::destroy()
+{
+    delete m_instance;
+    m_instance = nullptr;
+}
 
 static inline bool isQStringInUse(const QString &string)
 {
@@ -88,7 +126,7 @@ static inline bool isQStringInUse(const QString &string)
     return data_ptr->ref.isShared() || data_ptr->ref.isStatic();
 }
 
-void StringTable::GC()
+void StringTablePrivate::GC()
 {
     QMutexLocker locker(&m_lock);
 
diff --git a/src/plugins/cpptools/stringtable.h b/src/plugins/cpptools/stringtable.h
index 3eed7a0ed0..fdac41f1b1 100644
--- a/src/plugins/cpptools/stringtable.h
+++ b/src/plugins/cpptools/stringtable.h
@@ -25,45 +25,24 @@
 
 #pragma once
 
-#include <QAtomicInt>
-#include <QMutex>
-#include <QObject>
-#include <QRunnable>
-#include <QSet>
-#include <QTimer>
+#include <QString>
 
 namespace CppTools {
 namespace Internal {
 
-class StringTable: public QObject
-{
-    Q_OBJECT
+class CppToolsPluginPrivate;
 
+class StringTable
+{
 public:
-    StringTable();
-
-    QString insert(const QString &string);
-    void scheduleGC();
-
-private:
-    void startGC();
-    void GC();
-
-    class GCRunner: public QRunnable {
-        StringTable &m_stringTable;
-
-    public:
-        GCRunner(StringTable &stringTable): m_stringTable(stringTable) {}
-        virtual void run() { m_stringTable.GC(); }
-    } m_gcRunner;
-    friend class GCRunner;
+    static QString insert(const QString &string);
+    static void scheduleGC();
 
 private:
-    mutable QMutex m_lock;
-    QAtomicInt m_stopGCRequested;
-    QSet<QString> m_strings;
-    QTimer m_gcCountDown;
+    friend class CppToolsPluginPrivate;
+    static void initialize();
+    static void destroy();
 };
 
-} // Internal namespace
-} // CppTools namespace
+} // Internal
+} // CppTools