C++: use a global string table for SearchSymbols.

This string table uniques strings, so that multiple identical strings
share their contents. It is used by the locator and the symbol searcher,
and will later be used by the class view.

Change-Id: Ib8b50f69bbf994d0d7a39b66dc8caf1a3d9bfb42
Reviewed-by: Nikolai Kosjar <nikolai.kosjar@digia.com>

src/plugins/cpptools/builtinindexingsupport.cpp

@@ -4,6 +4,7 @@
 #include "cpppreprocessor.h"
 #include "searchsymbols.h"
 #include "cpptoolsconstants.h"
+#include "cpptoolsplugin.h"
 #include "cppprojectfile.h"
 
 #include <coreplugin/icore.h>
@@ -107,7 +108,7 @@ public:
         future.setProgressValue(0);
         int progress = 0;
 
-        SearchSymbols search;
+        SearchSymbols search(CppToolsPlugin::stringTable());
         search.setSymbolsToSearchFor(m_parameters.types);
         CPlusPlus::Snapshot::const_iterator it = m_snapshot.begin();
 

src/plugins/cpptools/cppcurrentdocumentfilter.cpp

@@ -36,8 +36,10 @@
 using namespace CppTools::Internal;
 using namespace CPlusPlus;
 
-CppCurrentDocumentFilter::CppCurrentDocumentFilter(CppModelManager *manager)
+CppCurrentDocumentFilter::CppCurrentDocumentFilter(CppModelManager *manager,
+                                                   StringTable &stringTable)
     : m_modelManager(manager)
+    , search(stringTable)
 {
     setId("Methods in current Document");
     setDisplayName(tr("C++ Symbols in Current Document"));
@@ -57,7 +59,8 @@ CppCurrentDocumentFilter::CppCurrentDocumentFilter(CppModelManager *manager)
             this,          SLOT(onEditorAboutToClose(Core::IEditor*)));
 }
 
-QList<Core::LocatorFilterEntry> CppCurrentDocumentFilter::matchesFor(QFutureInterface<Core::LocatorFilterEntry> &future, const QString & origEntry)
+QList<Core::LocatorFilterEntry> CppCurrentDocumentFilter::matchesFor(
+        QFutureInterface<Core::LocatorFilterEntry> &future, const QString & origEntry)
 {
     QString entry = trimWildcards(origEntry);
     QList<Core::LocatorFilterEntry> goodEntries;

src/plugins/cpptools/cppcurrentdocumentfilter.h

@@ -45,7 +45,8 @@ class CppCurrentDocumentFilter : public  Core::ILocatorFilter
     Q_OBJECT
 
 public:
-    explicit CppCurrentDocumentFilter(CppModelManager *manager);
+    explicit CppCurrentDocumentFilter(CppModelManager *manager,
+                                      StringTable &stringTable);
     ~CppCurrentDocumentFilter() {}
 
     QList<Core::LocatorFilterEntry> matchesFor(QFutureInterface<Core::LocatorFilterEntry> &future, const QString &entry);

src/plugins/cpptools/cpplocatordata.cpp

@@ -27,8 +27,8 @@
 **
 ****************************************************************************/
 
-
 #include "cpplocatordata.h"
+#include "cpptoolsplugin.h"
 
 using namespace CppTools;
 using namespace CppTools::Internal;
@@ -37,6 +37,8 @@ static const int MaxPendingDocuments = 10;
 
 CppLocatorData::CppLocatorData(CppModelManager *modelManager)
     : m_modelManager(modelManager)
+    , m_strings(CppToolsPlugin::stringTable())
+    , m_search(m_strings)
     , m_pendingDocumentsMutex(QMutex::Recursive)
 {
     m_search.setSymbolsToSearchFor(SymbolSearcher::Enums
@@ -104,8 +106,9 @@ void CppLocatorData::onAboutToRemoveFiles(const QStringList &files)
         m_allEnums.remove(file);
         m_allClasses.remove(file);
         m_allFunctions.remove(file);
-        removeFilePath(file);
     }
+
+    m_strings.scheduleGC();
 }
 
 void CppLocatorData::flushPendingDocument(bool force)

src/plugins/cpptools/cpplocatordata.h

@@ -38,6 +38,7 @@
 
 #include "cppmodelmanager.h"
 #include "searchsymbols.h"
+#include "stringtable.h"
 
 namespace CppTools {
 namespace Internal {
@@ -62,15 +63,12 @@ private:
                                            QList<ModelItemInfo> > &items) const;
 
     QString findOrInsertFilePath(const QString &path)
-    { return *m_filePaths.insert(path); }
-
-    void removeFilePath(const QString &path)
-    { m_filePaths.remove(path); }
+    { return m_strings.insert(path); }
 
 private:
     CppModelManager *m_modelManager;
 
-    QSet<QString> m_filePaths; // Used to avoid QString duplication
+    StringTable &m_strings; // Used to avoid QString duplication
 
     SearchSymbols m_search;
     QHash<QString, QList<ModelItemInfo> > m_allEnums;

src/plugins/cpptools/cpptools.pro

@@ -52,6 +52,7 @@ HEADERS += \
     includeutils.h \
     insertionpointlocator.h \
     searchsymbols.h \
+    stringtable.h \
     symbolfinder.h \
     symbolsfindfilter.h \
     typehierarchybuilder.h
@@ -104,6 +105,7 @@ SOURCES += \
     includeutils.cpp \
     insertionpointlocator.cpp \
     searchsymbols.cpp \
+    stringtable.cpp \
     symbolfinder.cpp \
     symbolsfindfilter.cpp \
     typehierarchybuilder.cpp

src/plugins/cpptools/cpptools.qbs

@@ -72,6 +72,7 @@ QtcPlugin {
         "includeutils.cpp", "includeutils.h",
         "insertionpointlocator.cpp", "insertionpointlocator.h",
         "searchsymbols.cpp", "searchsymbols.h",
+        "stringtable.cpp", "stringtable.h",
         "symbolfinder.cpp", "symbolfinder.h",
         "symbolsfindfilter.cpp", "symbolsfindfilter.h",
         "typehierarchybuilder.cpp", "typehierarchybuilder.h",

src/plugins/cpptools/cpptoolsplugin.cpp

@@ -136,7 +136,7 @@ bool CppToolsPlugin::initialize(const QStringList &arguments, QString *error)
     addAutoReleasedObject(new CppLocatorFilter(locatorData));
     addAutoReleasedObject(new CppClassesFilter(locatorData));
     addAutoReleasedObject(new CppFunctionsFilter(locatorData));
-    addAutoReleasedObject(new CppCurrentDocumentFilter(modelManager));
+    addAutoReleasedObject(new CppCurrentDocumentFilter(modelManager, m_stringTable));
     addAutoReleasedObject(new CppFileSettingsPage(m_fileSettings));
     addAutoReleasedObject(new CppCodeModelSettingsPage(m_codeModelSettings));
     addAutoReleasedObject(new SymbolsFindFilter(modelManager));
@@ -190,6 +190,11 @@ QSharedPointer<CppCodeModelSettings> CppToolsPlugin::codeModelSettings() const
     return m_codeModelSettings;
 }
 
+StringTable &CppToolsPlugin::stringTable()
+{
+    return instance()->m_stringTable;
+}
+
 void CppToolsPlugin::switchHeaderSource()
 {
     QString otherFile = correspondingHeaderOrSource(

src/plugins/cpptools/cpptoolsplugin.h

@@ -31,6 +31,7 @@
 #define CPPTOOLS_H
 
 #include "cpptools_global.h"
+#include "stringtable.h"
 
 #include <projectexplorer/projectexplorer.h>
 
@@ -73,6 +74,8 @@ public:
 
     QSharedPointer<CppCodeModelSettings> codeModelSettings() const;
 
+    static StringTable &stringTable();
+
 public slots:
     void switchHeaderSource();
     void switchHeaderSourceInNextSplit();
@@ -163,6 +166,7 @@ private:
     QSharedPointer<CppFileSettings> m_fileSettings;
     QSharedPointer<CppCodeModelSettings> m_codeModelSettings;
     CppToolsSettings *m_settings;
+    StringTable m_stringTable;
 };
 
 } // namespace Internal

src/plugins/cpptools/searchsymbols.cpp

@@ -42,8 +42,9 @@ SearchSymbols::SymbolTypes SearchSymbols::AllTypes =
         | SymbolSearcher::Enums
         | SymbolSearcher::Declarations;
 
-SearchSymbols::SearchSymbols() :
-    symbolsToSearchFor(SymbolSearcher::Classes | SymbolSearcher::Functions | SymbolSearcher::Enums)
+SearchSymbols::SearchSymbols(Internal::StringTable &stringTable)
+    : strings(stringTable)
+    , symbolsToSearchFor(SymbolSearcher::Classes | SymbolSearcher::Functions | SymbolSearcher::Enums)
 {
 }
 
@@ -62,7 +63,7 @@ QList<ModelItemInfo> SearchSymbols::operator()(Document::Ptr doc, int sizeHint,
     }
     (void) switchScope(previousScope);
     QList<ModelItemInfo> result = items;
-    strings.clear();
+    strings.scheduleGC();
     items.clear();
     m_paths.clear();
     return result;
@@ -291,7 +292,7 @@ void SearchSymbols::appendItem(const QString &symbolName, const QString &symbolT
                                findOrInsert(symbolType),
                                findOrInsert(symbolScope),
                                itemType,
-                               path,
+                               findOrInsert(path),
                                symbol->line(),
                                symbol->column() - 1, // 1-based vs 0-based column
                                icon));

src/plugins/cpptools/searchsymbols.h

@@ -32,6 +32,7 @@
 
 #include "cpptools_global.h"
 #include "cppindexingsupport.h"
+#include "stringtable.h"
 
 #include <cplusplus/CppDocument.h>
 #include <cplusplus/Icons.h>
@@ -140,7 +141,7 @@ public:
 
     static SymbolTypes AllTypes;
 
-    SearchSymbols();
+    SearchSymbols(Internal::StringTable &stringTable);
 
     void setSymbolsToSearchFor(const SymbolTypes &types);
 
@@ -193,9 +194,9 @@ protected:
 
 private:
     QString findOrInsert(const QString &s)
-    { return *strings.insert(s); }
+    { return strings.insert(s); }
 
-    QSet<QString> strings;            // Used to avoid QString duplication
+    Internal::StringTable &strings;            // Used to avoid QString duplication
 
     QString _scope;
     CPlusPlus::Overview overview;

src/plugins/cpptools/stringtable.cpp

@@ -0,0 +1,116 @@
+/****************************************************************************
+**
+** Copyright (C) 2014 Digia Plc and/or its subsidiary(-ies).
+** Contact: http://www.qt-project.org/legal
+**
+** This file is part of Qt Creator.
+**
+** Commercial License Usage
+** Licensees holding valid commercial Qt licenses may use this file in
+** accordance with the commercial license agreement provided with the
+** Software or, alternatively, in accordance with the terms contained in
+** a written agreement between you and Digia.  For licensing terms and
+** conditions see http://qt.digia.com/licensing.  For further information
+** use the contact form at http://qt.digia.com/contact-us.
+**
+** GNU Lesser General Public License Usage
+** Alternatively, this file may be used under the terms of the GNU Lesser
+** General Public License version 2.1 as published by the Free Software
+** Foundation and appearing in the file LICENSE.LGPL included in the
+** packaging of this file.  Please review the following information to
+** ensure the GNU Lesser General Public License version 2.1 requirements
+** will be met: http://www.gnu.org/licenses/old-licenses/lgpl-2.1.html.
+**
+** In addition, as a special exception, Digia gives you certain additional
+** rights.  These rights are described in the Digia Qt LGPL Exception
+** version 1.1, included in the file LGPL_EXCEPTION.txt in this package.
+**
+****************************************************************************/
+
+#include "stringtable.h"
+
+#include <QDebug>
+#include <QThreadPool>
+#include <QTime>
+
+using namespace CppTools::Internal;
+
+enum {
+    GCTimeOut = 10 * 1000 // 10 seconds
+};
+
+StringTable::StringTable()
+    : m_gcRunner(*this)
+    , m_stopGCRequested(false)
+{
+    m_strings.reserve(1000);
+
+    m_gcRunner.setAutoDelete(false);
+
+    m_gcCountDown.setSingleShot(true);
+    m_gcCountDown.setInterval(GCTimeOut);
+    connect(&m_gcCountDown, SIGNAL(timeout()),
+            this, SLOT(startGC()));
+}
+
+QString StringTable::insert(const QString &string)
+{
+    if (string.isEmpty())
+        return string;
+
+
+    m_stopGCRequested.fetchAndStoreAcquire(true);
+
+    QMutexLocker locker(&m_lock);
+    QString result = *m_strings.insert(string);
+    m_stopGCRequested.storeRelease(false);
+    return result;
+}
+
+void StringTable::scheduleGC()
+{
+    QMutexLocker locker(&m_lock);
+
+    m_gcCountDown.start();
+}
+
+void StringTable::startGC()
+{
+    QThreadPool::globalInstance()->start(&m_gcRunner);
+}
+
+enum {
+    DebugStringTable = 0
+};
+
+void StringTable::GC()
+{
+    QMutexLocker locker(&m_lock);
+
+    int initialSize = 0;
+    int startTime = 0;
+    if (DebugStringTable) {
+        initialSize = m_strings.size();
+        startTime = QTime::currentTime().msecsSinceStartOfDay();
+    }
+
+    // Collect all QStrings which have refcount 1. (One reference in m_strings and nowhere else.)
+    for (QSet<QString>::iterator i = m_strings.begin(); i != m_strings.end();) {
+        if (m_stopGCRequested.testAndSetRelease(true, false))
+            return;
+
+        const int refCount = const_cast<QString&>(*i).data_ptr()->ref.atomic.load();
+        if (refCount == 1)
+            i = m_strings.erase(i);
+        else
+            ++i;
+    }
+
+    if (DebugStringTable) {
+        const int endTime = QTime::currentTime().msecsSinceStartOfDay();
+        const int currentSize = m_strings.size();
+        qDebug() << "StringTable::GC removed" << initialSize - currentSize
+                 << "strings in" << endTime - startTime
+                 << "ms, size is now" << currentSize;
+    }
+}

src/plugins/cpptools/stringtable.h

@@ -0,0 +1,77 @@
+/****************************************************************************
+**
+** Copyright (C) 2014 Digia Plc and/or its subsidiary(-ies).
+** Contact: http://www.qt-project.org/legal
+**
+** This file is part of Qt Creator.
+**
+** Commercial License Usage
+** Licensees holding valid commercial Qt licenses may use this file in
+** accordance with the commercial license agreement provided with the
+** Software or, alternatively, in accordance with the terms contained in
+** a written agreement between you and Digia.  For licensing terms and
+** conditions see http://qt.digia.com/licensing.  For further information
+** use the contact form at http://qt.digia.com/contact-us.
+**
+** GNU Lesser General Public License Usage
+** Alternatively, this file may be used under the terms of the GNU Lesser
+** General Public License version 2.1 as published by the Free Software
+** Foundation and appearing in the file LICENSE.LGPL included in the
+** packaging of this file.  Please review the following information to
+** ensure the GNU Lesser General Public License version 2.1 requirements
+** will be met: http://www.gnu.org/licenses/old-licenses/lgpl-2.1.html.
+**
+** In addition, as a special exception, Digia gives you certain additional
+** rights.  These rights are described in the Digia Qt LGPL Exception
+** version 1.1, included in the file LGPL_EXCEPTION.txt in this package.
+**
+****************************************************************************/
+
+#ifndef STRINGTABLE_H
+#define STRINGTABLE_H
+
+#include <QAtomicInt>
+#include <QMutex>
+#include <QObject>
+#include <QRunnable>
+#include <QSet>
+#include <QTimer>
+
+namespace CppTools {
+namespace Internal {
+
+class StringTable: public QObject
+{
+    Q_OBJECT
+
+public:
+    StringTable();
+
+    QString insert(const QString &string);
+    void scheduleGC();
+
+private slots:
+    void startGC();
+
+private:
+    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;
+
+private:
+    mutable QMutex m_lock;
+    QAtomicInt m_stopGCRequested;
+    QSet<QString> m_strings;
+    QTimer m_gcCountDown;
+};
+
+} // Internal namespace
+} // CppTools namespace
+
+#endif // STRINGTABLE_H