introduce classes FileTag and FileTags

Stop inconsistent usage of QSet<QString> and QList<QString> to
hold file tags. This is now unified by using a FileTags container
class. The FileTag class is an alias for Id.

Task-number: QBS-170

Change-Id: I8917942c4327a45d3d3604f4dc39bdee12801fdb
Reviewed-by: Christian Kandeler <christian.kandeler@digia.com>

27 files changed, 343 insertions, 159 deletions

diff --git a/src/lib/api/internaljobs.cpp b/src/lib/api/internaljobs.cpp
index 31486e520..cad5399db 100644
--- a/src/lib/api/internaljobs.cpp
+++ b/src/lib/api/internaljobs.cpp
@@ -196,7 +196,7 @@ void InternalSetupProjectJob::execute()
     logger().qbsDebug() << QString::fromLocal8Bit("for %1:").arg(rProject->id());
     foreach (const ResolvedProductConstPtr &p, rProject->products) {
         logger().qbsDebug() << QString::fromLocal8Bit("  - [%1] %2 as %3")
-                               .arg(p->fileTags.join(QLatin1String(", ")))
+                               .arg(p->fileTags.toStringList().join(QLatin1String(", ")))
                                .arg(p->name).arg(p->project->id());
     }
     logger().qbsDebug() << '\n';
diff --git a/src/lib/api/project.cpp b/src/lib/api/project.cpp
index 69f3abff7..afbdd72ef 100644
--- a/src/lib/api/project.cpp
+++ b/src/lib/api/project.cpp
@@ -194,7 +194,7 @@ void ProjectPrivate::retrieveProjectData()
         ProductData product;
         product.m_name = resolvedProduct->name;
         product.m_location = resolvedProduct->location;
-        product.m_fileTags = resolvedProduct->fileTags;
+        product.m_fileTags = resolvedProduct->fileTags.toStringList();
         product.m_properties = resolvedProduct->properties->value();
         product.m_isEnabled = resolvedProduct->enabled;
         foreach (const GroupPtr &resolvedGroup, resolvedProduct->groups) {
@@ -357,11 +357,11 @@ QString Project::targetExecutable(const ProductData &product, const QString &_in
     if (!product.isEnabled())
         return QString();
     const BuildProductConstPtr buildProduct = d->internalProduct(product);
-    if (!buildProduct->rProduct->fileTags.contains(QLatin1String("application")))
+    if (!buildProduct->rProduct->fileTags.contains("application"))
         return QString();
 
     foreach (const Artifact * const artifact, buildProduct->targetArtifacts) {
-        if (artifact->fileTags.contains(QLatin1String("application"))) {
+        if (artifact->fileTags.contains("application")) {
             if (!artifact->properties->qbsPropertyValue(QLatin1String("install")).toBool())
                 return artifact->filePath();
             const QString fileName = FileInfo::fileName(artifact->filePath());
diff --git a/src/lib/buildgraph/artifact.cpp b/src/lib/buildgraph/artifact.cpp
index f5df0d261..b85219701 100644
--- a/src/lib/buildgraph/artifact.cpp
+++ b/src/lib/buildgraph/artifact.cpp
@@ -81,11 +81,11 @@ void Artifact::setFilePath(const QString &filePath)
 void Artifact::load(PersistentPool &pool)
 {
     setFilePath(pool.idLoadString());
-    fileTags = pool.idLoadStringSet();
     properties = pool.idLoadS<PropertyMap>();
     transformer = pool.idLoadS<Transformer>();
     unsigned char c;
     pool.stream()
+            >> fileTags
             >> artifactType
             >> timestamp
             >> autoMocTimestamp
@@ -96,10 +96,10 @@ void Artifact::load(PersistentPool &pool)
 void Artifact::store(PersistentPool &pool) const
 {
     pool.storeString(m_filePath);
-    pool.storeStringSet(fileTags);
     pool.store(properties);
     pool.store(transformer);
     pool.stream()
+            << fileTags
             << artifactType
             << timestamp
             << autoMocTimestamp
diff --git a/src/lib/buildgraph/artifact.h b/src/lib/buildgraph/artifact.h
index 0485f876f..b6e88d93a 100644
--- a/src/lib/buildgraph/artifact.h
+++ b/src/lib/buildgraph/artifact.h
@@ -32,11 +32,11 @@
 
 #include "artifactlist.h"
 #include "forward_decls.h"
+#include <language/filetags.h>
 #include <language/forward_decls.h>
 #include <tools/filetime.h>
 #include <tools/persistentobject.h>
 
-#include <QSet>
 #include <QString>
 
 namespace qbs {
@@ -63,7 +63,7 @@ public:
     ArtifactList parents;
     ArtifactList children;
     ArtifactList fileDependencies;
-    QSet<QString> fileTags;
+    FileTags fileTags;
     BuildProject *project;
     BuildProduct *product;          // Note: file dependency artifacts don't belong to a product.
     TransformerPtr transformer;
diff --git a/src/lib/buildgraph/automoc.cpp b/src/lib/buildgraph/automoc.cpp
index 88f65597a..e3b85c068 100644
--- a/src/lib/buildgraph/automoc.cpp
+++ b/src/lib/buildgraph/automoc.cpp
@@ -45,15 +45,15 @@
 namespace qbs {
 namespace Internal {
 
-static char **createCFileTags(const QSet<QString> &fileTags)
+static char **createCFileTags(const FileTags &fileTags)
 {
     if (fileTags.isEmpty())
         return 0;
 
     char **buf = new char*[fileTags.count()];
     size_t i = 0;
-    foreach (const QString &fileTag, fileTags) {
-        buf[i] = qstrdup(fileTag.toLocal8Bit().data());
+    foreach (const FileTag &fileTag, fileTags) {
+        buf[i] = qstrdup(fileTag.toString().toLocal8Bit().data());
         ++i;
     }
     return buf;
@@ -94,15 +94,15 @@ void AutoMoc::apply(const BuildProductPtr &product)
     for (; it != product->artifacts.end(); ++it) {
         Artifact *artifact = *it;
         if (!pchFile || !pluginMetaDataFile) {
-            foreach (const QString &fileTag, artifact->fileTags) {
-                if (fileTag == QLatin1String("c++_pch"))
+            foreach (const FileTag &fileTag, artifact->fileTags) {
+                if (fileTag == "c++_pch")
                     pchFile = artifact;
-                else if (fileTag == QLatin1String("qt_plugin_metadata"))
+                else if (fileTag == "qt_plugin_metadata")
                     pluginMetaDataFile = artifact;
             }
         }
 
-        if (!pluginMetaDataFile && artifact->fileTags.contains(QLatin1String("qt_plugin_metadata"))) {
+        if (!pluginMetaDataFile && artifact->fileTags.contains("qt_plugin_metadata")) {
             if (m_logger.debugEnabled()) {
                 m_logger.qbsDebug() << "[AUTOMOC] found Qt plugin metadata file "
                                     << artifact->filePath();
@@ -117,7 +117,7 @@ void AutoMoc::apply(const BuildProductPtr &product)
         const FileType fileType = AutoMoc::fileType(artifact);
         if (fileType == UnknownFileType)
             continue;
-        QString mocFileTag;
+        FileTag mocFileTag;
         bool alreadyMocced = isVictimOfMoc(artifact, fileType, mocFileTag);
         bool hasQObjectMacro;
         scan(artifact, hasQObjectMacro, includedMocCppFiles);
@@ -134,22 +134,22 @@ void AutoMoc::apply(const BuildProductPtr &product)
         const QPair<Artifact *, FileType> &p = artifactsToMoc.at(i);
         Artifact * const artifact = p.first;
         FileType fileType = p.second;
-        foreach (const QString &fileTag, artifact->fileTags) {
-            if (fileTag == QLatin1String("moc_hpp")) {
+        foreach (const FileTag &fileTag, artifact->fileTags) {
+            if (fileTag == "moc_hpp") {
                 const QString mocFileName = generateMocFileName(artifact, fileType);
                 if (includedMocCppFiles.contains(mocFileName)) {
-                    QString newFileTag = QLatin1String("moc_hpp_inc");
+                    FileTag newFileTag = "moc_hpp_inc";
                     artifact->fileTags -= fileTag;
                     artifact->fileTags += newFileTag;
                     artifactsPerFileTag[newFileTag].insert(artifact);
                     continue;
                 }
-            } else if (fileTag == QLatin1String("moc_plugin_hpp")) {
+            } else if (fileTag == "moc_plugin_hpp") {
                 if (m_logger.debugEnabled()) {
                     m_logger.qbsDebug() << "[AUTOMOC] found Qt plugin header file "
                                         << artifact->filePath();
                 }
-                QString newFileTag = QLatin1String("moc_hpp");
+                FileTag newFileTag = "moc_hpp";
                 artifact->fileTags -= fileTag;
                 artifact->fileTags += newFileTag;
                 artifactsPerFileTag[newFileTag].insert(artifact);
@@ -160,7 +160,7 @@ void AutoMoc::apply(const BuildProductPtr &product)
     }
 
     if (pchFile)
-        artifactsPerFileTag[QLatin1String("c++_pch")] += pchFile;
+        artifactsPerFileTag["c++_pch"] += pchFile;
     if (!artifactsPerFileTag.isEmpty()) {
         emit reportCommandDescription(QLatin1String("automoc"),
                                       Tr::tr("Applying moc rules for '%1'.")
@@ -195,10 +195,10 @@ QString AutoMoc::generateMocFileName(Artifact *artifact, FileType fileType)
 
 AutoMoc::FileType AutoMoc::fileType(Artifact *artifact)
 {
-    foreach (const QString &fileTag, artifact->fileTags)
-        if (fileTag == QLatin1String("hpp"))
+    foreach (const FileTag &fileTag, artifact->fileTags)
+        if (fileTag == "hpp")
             return HppFileType;
-        else if (fileTag == QLatin1String("cpp"))
+        else if (fileTag == "cpp")
             return CppFileType;
     return UnknownFileType;
 }
@@ -222,10 +222,12 @@ void AutoMoc::scan(Artifact *artifact, bool &hasQObjectMacro, QSet<QString> &inc
         const char **szFileTagsFromScanner = scanner->additionalFileTags(opaq, &length);
         if (szFileTagsFromScanner && length > 0) {
             for (int i=length; --i >= 0;) {
-                const QString fileTagFromScanner = QString::fromLocal8Bit(szFileTagsFromScanner[i]);
-                artifact->fileTags.insert(fileTagFromScanner);
+                artifact->fileTags.insert(szFileTagsFromScanner[i]);
                 if (m_logger.traceEnabled())
                     m_logger.qbsTrace() << "[AUTOMOC] finds Q_OBJECT macro";
+                const QByteArray fileTagFromScanner
+                        = QByteArray::fromRawData(szFileTagsFromScanner[i],
+                                                  strlen(szFileTagsFromScanner[i]));
                 if (fileTagFromScanner.startsWith("moc"))
                     hasQObjectMacro = true;
             }
@@ -272,18 +274,23 @@ void AutoMoc::scan(Artifact *artifact, bool &hasQObjectMacro, QSet<QString> &inc
     freeCFileTags(cFileTags, numFileTags);
 }
 
-bool AutoMoc::isVictimOfMoc(Artifact *artifact, FileType fileType, QString &foundMocFileTag)
+static FileTags provideMocHeaderFileTags()
 {
-    static const QSet<QString> mocHeaderFileTags = QSet<QString>() << QLatin1String("moc_hpp")
-                                                                   << QLatin1String("moc_hpp_inc")
-                                                                   << QLatin1String("moc_plugin_hpp");
-    static const QString mocCppFileTag = QLatin1String("moc_cpp");
+    FileTags fileTags;
+    fileTags << "moc_hpp" << "moc_hpp_inc" << "moc_plugin_hpp";
+    return fileTags;
+}
+
+bool AutoMoc::isVictimOfMoc(Artifact *artifact, FileType fileType, FileTag &foundMocFileTag)
+{
+    static const FileTags mocHeaderFileTags = provideMocHeaderFileTags();
+    static const FileTag mocCppFileTag = "moc_cpp";
     foundMocFileTag.clear();
     switch (fileType) {
     case UnknownFileType:
         break;
     case HppFileType:
-        foreach (const QString &fileTag, artifact->fileTags) {
+        foreach (const FileTag &fileTag, artifact->fileTags) {
             if (mocHeaderFileTags.contains(fileTag)) {
                 foundMocFileTag = fileTag;
                 break;
@@ -295,10 +302,10 @@ bool AutoMoc::isVictimOfMoc(Artifact *artifact, FileType fileType, QString &foun
             foundMocFileTag = mocCppFileTag;
         break;
     }
-    return !foundMocFileTag.isEmpty();
+    return foundMocFileTag.isValid();
 }
 
-void AutoMoc::unmoc(Artifact *artifact, const QString &mocFileTag)
+void AutoMoc::unmoc(Artifact *artifact, const FileTag &mocFileTag)
 {
     if (m_logger.traceEnabled())
         m_logger.qbsTrace() << "[AUTOMOC] unmoc'ing " << relativeArtifactFileName(artifact);
@@ -307,7 +314,7 @@ void AutoMoc::unmoc(Artifact *artifact, const QString &mocFileTag)
 
     Artifact *generatedMocArtifact = 0;
     foreach (Artifact *parent, artifact->parents) {
-        foreach (const QString &fileTag, parent->fileTags) {
+        foreach (const FileTag &fileTag, parent->fileTags) {
             if (fileTag == "hpp" || fileTag == "cpp") {
                 generatedMocArtifact = parent;
                 break;
@@ -323,7 +330,7 @@ void AutoMoc::unmoc(Artifact *artifact, const QString &mocFileTag)
     if (mocFileTag == "moc_hpp") {
         Artifact *mocObjArtifact = 0;
         foreach (Artifact *parent, generatedMocArtifact->parents) {
-            foreach (const QString &fileTag, parent->fileTags) {
+            foreach (const FileTag &fileTag, parent->fileTags) {
                 if (fileTag == "obj" || fileTag == "fpicobj") {
                     mocObjArtifact = parent;
                     break;
diff --git a/src/lib/buildgraph/automoc.h b/src/lib/buildgraph/automoc.h
index 524155858..6d6b7c510 100644
--- a/src/lib/buildgraph/automoc.h
+++ b/src/lib/buildgraph/automoc.h
@@ -40,6 +40,7 @@ struct ScannerPlugin;
 
 namespace qbs {
 namespace Internal {
+class FileTag;
 class ScanResultCache;
 
 /**
@@ -75,8 +76,8 @@ private:
     static QString generateMocFileName(Artifact *artifact, FileType fileType);
     static FileType fileType(Artifact *artifact);
     void scan(Artifact *artifact, bool &hasQObjectMacro, QSet<QString> &includedMocCppFiles);
-    bool isVictimOfMoc(Artifact *artifact, FileType fileType, QString &foundMocFileTag);
-    void unmoc(Artifact *artifact, const QString &mocFileTag);
+    bool isVictimOfMoc(Artifact *artifact, FileType fileType, FileTag &foundMocFileTag);
+    void unmoc(Artifact *artifact, const FileTag &mocFileTag);
     QList<ScannerPlugin *> scanners() const;
 
     mutable QList<ScannerPlugin *> m_scanners;
diff --git a/src/lib/buildgraph/buildproduct.cpp b/src/lib/buildgraph/buildproduct.cpp
index 1459a6168..2cfed960b 100644
--- a/src/lib/buildgraph/buildproduct.cpp
+++ b/src/lib/buildgraph/buildproduct.cpp
@@ -65,7 +65,7 @@ static void internalDump(const BuildProduct *product, Artifact *artifact, QByteA
            qPrintable(QString(toString(artifact->buildState).at(0))),
            artifactInProduct ? "" : " SBS",     // SBS == side-by-side artifact from other product
            qPrintable(artifact->filePath()),
-           qPrintable(QStringList(artifact->fileTags.toList()).join(",")));
+           qPrintable(artifact->fileTags.toStringList().join(QLatin1String(", "))));
     printf("\n");
     indent.append("  ");
     foreach (Artifact *child, artifact->children) {
@@ -83,12 +83,10 @@ void BuildProduct::dump() const
 const QList<RuleConstPtr> &BuildProduct::topSortedRules() const
 {
     if (m_topSortedRules.isEmpty()) {
-        QStringList fileTags;
-        fileTags << rProduct->fileTags << rProduct->additionalFileTags;
-        fileTags.sort();
-        std::unique(fileTags.begin(), fileTags.end());
+        FileTags productFileTags = rProduct->fileTags;
+        productFileTags += rProduct->additionalFileTags;
         RuleGraph ruleGraph;
-        ruleGraph.build(rProduct->rules, fileTags);
+        ruleGraph.build(rProduct->rules, productFileTags);
 //        ruleGraph.dump();
         m_topSortedRules = ruleGraph.topSorted();
 //        int i=0;
diff --git a/src/lib/buildgraph/buildproject.cpp b/src/lib/buildgraph/buildproject.cpp
index e4b8d15ef..84f58c70e 100644
--- a/src/lib/buildgraph/buildproject.cpp
+++ b/src/lib/buildgraph/buildproject.cpp
@@ -246,7 +246,7 @@ void BuildProject::updateNodeThatMustGetNewTransformer(Artifact *artifact)
 
     ArtifactsPerFileTagMap artifactsPerFileTag;
     foreach (Artifact *input, artifact->children) {
-        foreach (const QString &fileTag, input->fileTags)
+        foreach (const FileTag &fileTag, input->fileTags)
             artifactsPerFileTag[fileTag] += input;
     }
     RulesApplicator rulesApplier(artifact->product, artifactsPerFileTag, m_logger);
@@ -313,7 +313,7 @@ BuildProjectPtr BuildProjectResolver::resolveProject(const ResolvedProjectPtr &r
 static void addTargetArtifacts(const BuildProductPtr &product,
                               ArtifactsPerFileTagMap &artifactsPerFileTag, const Logger &logger)
 {
-    foreach (const QString &fileTag, product->rProduct->fileTags) {
+    foreach (const FileTag &fileTag, product->rProduct->fileTags) {
         foreach (Artifact * const artifact, artifactsPerFileTag.value(fileTag)) {
             if (artifact->artifactType == Artifact::Generated)
                 product->targetArtifacts += artifact;
@@ -369,7 +369,7 @@ BuildProductPtr BuildProjectResolver::resolveProduct(const ResolvedProductPtr &r
             continue; // ignore duplicate artifacts
 
         Artifact *artifact = product->createArtifact(sourceArtifact, m_logger);
-        foreach (const QString &fileTag, artifact->fileTags)
+        foreach (const FileTag &fileTag, artifact->fileTags)
             artifactsPerFileTag[fileTag].insert(artifact);
     }
 
@@ -385,7 +385,6 @@ BuildProductPtr BuildProjectResolver::resolveProduct(const ResolvedProductPtr &r
         TransformerPtr transformer = Transformer::create();
         transformer->inputs = inputArtifacts;
         const RulePtr rule = Rule::create();
-        rule->inputs = rtrafo->inputs;
         rule->jsImports = rtrafo->jsImports;
         ResolvedModulePtr module = ResolvedModule::create();
         module->name = rtrafo->module->name;
@@ -399,12 +398,12 @@ BuildProductPtr BuildProjectResolver::resolveProduct(const ResolvedProductPtr &r
             product->targetArtifacts += outputArtifact;
             foreach (Artifact *inputArtifact, inputArtifacts)
                 safeConnect(outputArtifact, inputArtifact, m_logger);
-            foreach (const QString &fileTag, outputArtifact->fileTags)
+            foreach (const FileTag &fileTag, outputArtifact->fileTags)
                 artifactsPerFileTag[fileTag].insert(outputArtifact);
 
             RuleArtifactPtr ruleArtifact = RuleArtifact::create();
             ruleArtifact->fileName = outputArtifact->filePath();
-            ruleArtifact->fileTags = outputArtifact->fileTags.toList();
+            ruleArtifact->fileTags = outputArtifact->fileTags;
             rule->artifacts += ruleArtifact;
         }
         transformer->rule = rule;
@@ -654,11 +653,11 @@ void BuildProjectLoader::onProductChanged(const BuildProductPtr &product,
             QBS_CHECK(artifact);
 
             // handle added filetags
-            foreach (const QString &addedFileTag, changedArtifact->fileTags - a->fileTags)
+            foreach (const FileTag &addedFileTag, changedArtifact->fileTags - a->fileTags)
                 artifactsPerFileTag[addedFileTag] += artifact;
 
             // handle removed filetags
-            foreach (const QString &removedFileTag, a->fileTags - changedArtifact->fileTags) {
+            foreach (const FileTag &removedFileTag, a->fileTags - changedArtifact->fileTags) {
                 artifact->fileTags -= removedFileTag;
                 foreach (Artifact *parent, artifact->parents) {
                     if (parent->transformer && parent->transformer->rule->inputs.contains(removedFileTag)) {
@@ -676,7 +675,7 @@ void BuildProjectLoader::onProductChanged(const BuildProductPtr &product,
 
     // apply rules for new artifacts
     foreach (Artifact *artifact, addedArtifacts)
-        foreach (const QString &ft, artifact->fileTags)
+        foreach (const FileTag &ft, artifact->fileTags)
             artifactsPerFileTag[ft] += artifact;
     RulesApplicator(product.data(), artifactsPerFileTag, m_logger).applyAllRules();
 
diff --git a/src/lib/buildgraph/inputartifactscanner.cpp b/src/lib/buildgraph/inputartifactscanner.cpp
index 0d5c98e70..4085e5a58 100644
--- a/src/lib/buildgraph/inputartifactscanner.cpp
+++ b/src/lib/buildgraph/inputartifactscanner.cpp
@@ -173,7 +173,7 @@ void InputArtifactScanner::scan()
         bool mustCollectIncludePaths = false;
 
         QSet<ScannerPlugin *> scanners;
-        foreach (const QString &fileTag, inputArtifact->fileTags) {
+        foreach (const FileTag &fileTag, inputArtifact->fileTags) {
             foreach (ScannerPlugin *scanner, ScannerPluginManager::scannersForFileTag(fileTag)) {
                 scanners += scanner;
                 if (scanner->flags & ScannerUsesCppIncludePaths)
diff --git a/src/lib/buildgraph/rulegraph.cpp b/src/lib/buildgraph/rulegraph.cpp
index 73779ebac..fa922dfb9 100644
--- a/src/lib/buildgraph/rulegraph.cpp
+++ b/src/lib/buildgraph/rulegraph.cpp
@@ -38,12 +38,12 @@ RuleGraph::RuleGraph()
 {
 }
 
-void RuleGraph::build(const QSet<RulePtr> &rules, const QStringList &productFileTags)
+void RuleGraph::build(const QSet<RulePtr> &rules, const FileTags &productFileTags)
 {
-    QMap<QString, QList<const Rule *> > inputFileTagToRule;
+    QMap<FileTag, QList<const Rule *> > inputFileTagToRule;
     m_artifacts.reserve(rules.count());
     foreach (const RulePtr &rule, rules) {
-        foreach (const QString &fileTag, rule->outputFileTags())
+        foreach (const FileTag &fileTag, rule->outputFileTags())
             m_outputFileTagToRule[fileTag].append(rule.data());
         insert(rule);
     }
@@ -52,9 +52,9 @@ void RuleGraph::build(const QSet<RulePtr> &rules, const QStringList &productFile
     m_children.resize(rules.count());
 
     foreach (const RuleConstPtr &rule, m_artifacts) {
-        QStringList inFileTags = rule->inputs;
+        FileTags inFileTags = rule->inputs;
         inFileTags += rule->explicitlyDependsOn;
-        foreach (const QString &fileTag, inFileTags) {
+        foreach (const FileTag &fileTag, inFileTags) {
             inputFileTagToRule[fileTag].append(rule.data());
             foreach (const Rule * const consumingRule, m_outputFileTagToRule.value(fileTag)) {
                 connect(rule.data(), consumingRule);
@@ -63,8 +63,8 @@ void RuleGraph::build(const QSet<RulePtr> &rules, const QStringList &productFile
     }
 
     QList<const Rule *> productRules;
-    for (int i=0; i < productFileTags.count(); ++i) {
-        QList<const Rule *> rules = m_outputFileTagToRule.value(productFileTags.at(i));
+    foreach (const FileTag &productFileTag, productFileTags) {
+        QList<const Rule *> rules = m_outputFileTagToRule.value(productFileTag);
         productRules += rules;
         //### check: the rule graph must be a in valid shape!
     }
diff --git a/src/lib/buildgraph/rulegraph.h b/src/lib/buildgraph/rulegraph.h
index d56bc298d..e1a511751 100644
--- a/src/lib/buildgraph/rulegraph.h
+++ b/src/lib/buildgraph/rulegraph.h
@@ -30,6 +30,7 @@
 #ifndef QBS_RULEGRAPH_H
 #define QBS_RULEGRAPH_H
 
+#include <language/filetags.h>
 #include <language/forward_decls.h>
 
 #include <QList>
@@ -46,7 +47,7 @@ class RuleGraph
 public:
     RuleGraph();
 
-    void build(const QSet<RulePtr> &rules, const QStringList &productFileTag);
+    void build(const QSet<RulePtr> &rules, const FileTags &productFileTag);
     QList<RuleConstPtr> topSorted();
 
     void dump() const;
@@ -61,7 +62,7 @@ private:
     QList<RuleConstPtr> topSort(const RuleConstPtr &rule);
 
 private:
-    QMap<QString, QList<const Rule*> > m_outputFileTagToRule;
+    QMap<FileTag, QList<const Rule*> > m_outputFileTagToRule;
     QVector<RulePtr> m_artifacts;
     QVector< QVector<int> > m_parents;
     QVector< QVector<int> > m_children;
diff --git a/src/lib/buildgraph/rulesapplicator.cpp b/src/lib/buildgraph/rulesapplicator.cpp
index dd089f11e..ee38933c6 100644
--- a/src/lib/buildgraph/rulesapplicator.cpp
+++ b/src/lib/buildgraph/rulesapplicator.cpp
@@ -70,7 +70,7 @@ void RulesApplicator::applyRule(const RuleConstPtr &rule)
                "BG", "Product object is not in current scope.");
 
     ArtifactList inputArtifacts;
-    foreach (const QString &fileTag, m_rule->inputs)
+    foreach (const FileTag &fileTag, m_rule->inputs)
         inputArtifacts.unite(m_artifactsPerFileTag.value(fileTag));
     if (m_rule->multiplex) { // apply the rule once for a set of inputs
         if (!inputArtifacts.isEmpty())
@@ -100,13 +100,13 @@ void RulesApplicator::doApply(const ArtifactList &inputArtifacts)
 
     ArtifactList usingArtifacts;
     if (!m_rule->usings.isEmpty()) {
-        const QSet<QString> usingsFileTags = m_rule->usings.toSet();
+        const FileTags usingsFileTags = m_rule->usings;
         foreach (const BuildProductPtr &dep, m_buildProduct->dependencies) {
             ArtifactList artifactsToCheck;
             foreach (Artifact *targetArtifact, dep->targetArtifacts)
                 artifactsToCheck.unite(targetArtifact->transformer->outputs);
             foreach (Artifact *artifact, artifactsToCheck) {
-                QSet<QString> matchingFileTags = artifact->fileTags;
+                FileTags matchingFileTags = artifact->fileTags;
                 matchingFileTags.intersect(usingsFileTags);
                 if (!matchingFileTags.isEmpty())
                     usingArtifacts.insert(artifact);
@@ -124,11 +124,11 @@ void RulesApplicator::doApply(const ArtifactList &inputArtifacts)
 
     foreach (Artifact *outputArtifact, outputArtifacts) {
         // insert the output artifacts into the pool of artifacts
-        foreach (const QString &fileTag, outputArtifact->fileTags)
+        foreach (const FileTag &fileTag, outputArtifact->fileTags)
             m_artifactsPerFileTag[fileTag].insert(outputArtifact);
 
         // connect artifacts that match the file tags in explicitlyDependsOn
-        foreach (const QString &fileTag, m_rule->explicitlyDependsOn)
+        foreach (const FileTag &fileTag, m_rule->explicitlyDependsOn)
             foreach (Artifact *dependency, m_artifactsPerFileTag.value(fileTag))
                 loggedConnect(outputArtifact, dependency, m_logger);
 
@@ -159,7 +159,8 @@ void RulesApplicator::doApply(const ArtifactList &inputArtifacts)
         outputArtifact->properties = outputArtifact->properties->clone();
 
         scope().setProperty("fileName", engine()->toScriptValue(outputArtifact->filePath()));
-        scope().setProperty("fileTags", toScriptValue(engine(), outputArtifact->fileTags));
+        scope().setProperty("fileTags",
+                            toScriptValue(engine(), outputArtifact->fileTags.toStringList()));
 
         QVariantMap artifactModulesCfg = outputArtifact->properties->value().value("modules").toMap();
         for (int i=0; i < ra->bindings.count(); ++i) {
@@ -236,10 +237,10 @@ Artifact *RulesApplicator::createOutputArtifact(const RuleArtifactConstPtr &rule
             m_transformer->inputs.unite(inputArtifacts);
 
             if (m_transformer->inputs.count() > 1 && !m_rule->multiplex) {
-                QString th = "[" + QStringList(outputArtifact->fileTags.toList()).join(", ") + "]";
+                QString th = "[" + outputArtifact->fileTags.toStringList().join(", ") + "]";
                 QString e = Tr::tr("Conflicting rules for producing %1 %2 \n").arg(outputArtifact->filePath(), th);
-                th = "[" + m_rule->inputs.join(", ")
-                   + "] -> [" + QStringList(outputArtifact->fileTags.toList()).join(", ") + "]";
+                th = "[" + m_rule->inputs.toStringList().join(", ")
+                   + "] -> [" + outputArtifact->fileTags.toStringList().join(", ") + "]";
 
                 e += QString("  while trying to apply:   %1:%2:%3  %4\n")
                     .arg(m_rule->script->location.fileName)
@@ -255,12 +256,12 @@ Artifact *RulesApplicator::createOutputArtifact(const RuleArtifactConstPtr &rule
                 throw Error(e);
             }
         }
-        outputArtifact->fileTags += ruleArtifact->fileTags.toSet();
+        outputArtifact->fileTags += ruleArtifact->fileTags;
     } else {
         outputArtifact = new Artifact(m_buildProduct->project);
         outputArtifact->artifactType = Artifact::Generated;
         outputArtifact->setFilePath(outputPath);
-        outputArtifact->fileTags = ruleArtifact->fileTags.toSet();
+        outputArtifact->fileTags = ruleArtifact->fileTags;
         outputArtifact->alwaysUpdated = ruleArtifact->alwaysUpdated;
         m_buildProduct->insertArtifact(outputArtifact, m_logger);
     }
@@ -275,7 +276,7 @@ Artifact *RulesApplicator::createOutputArtifact(const RuleArtifactConstPtr &rule
 
     for (int i = 0; i < m_buildProduct->rProduct->artifactProperties.count(); ++i) {
         const ArtifactPropertiesConstPtr &props = m_buildProduct->rProduct->artifactProperties.at(i);
-        QSet<QString> filter = props->fileTagsFilter().toSet();
+        FileTags filter = props->fileTagsFilter();
         if (!filter.intersect(outputArtifact->fileTags).isEmpty()) {
             outputArtifact->properties = props->propertyMap();
             break;
diff --git a/src/lib/buildgraph/rulesapplicator.h b/src/lib/buildgraph/rulesapplicator.h
index e9d4c9e9f..8aa5dae76 100644
--- a/src/lib/buildgraph/rulesapplicator.h
+++ b/src/lib/buildgraph/rulesapplicator.h
@@ -31,6 +31,7 @@
 
 #include "artifactlist.h"
 #include "forward_decls.h"
+#include <language/filetags.h>
 #include <language/forward_decls.h>
 #include <logging/logger.h>
 
@@ -42,7 +43,7 @@ namespace qbs {
 namespace Internal {
 class ScriptEngine;
 
-typedef QMap<QString, ArtifactList> ArtifactsPerFileTagMap;
+typedef QMap<FileTag, ArtifactList> ArtifactsPerFileTagMap;
 
 class RulesApplicator
 {
diff --git a/src/lib/buildgraph/transformer.cpp b/src/lib/buildgraph/transformer.cpp
index d9cf7d205..1e9d8adbc 100644
--- a/src/lib/buildgraph/transformer.cpp
+++ b/src/lib/buildgraph/transformer.cpp
@@ -55,7 +55,7 @@ QScriptValue Transformer::translateFileConfig(QScriptEngine *scriptEngine, Artif
     QScriptValue artifactConfig = scriptEngine->newObject();
     artifactConfig.setPrototype(config);
     artifactConfig.setProperty(QLatin1String("fileName"), artifact->filePath());
-    QStringList fileTags = artifact->fileTags.toList();
+    const QStringList fileTags = artifact->fileTags.toStringList();
     artifactConfig.setProperty(QLatin1String("fileTags"), scriptEngine->toScriptValue(fileTags));
     if (!defaultModuleName.isEmpty())
         artifactConfig.setProperty(QLatin1String("module"), config.property("modules").property(defaultModuleName));
@@ -67,8 +67,8 @@ QScriptValue Transformer::translateInOutputs(QScriptEngine *scriptEngine, const
     typedef QMap<QString, QList<Artifact*> > TagArtifactsMap;
     TagArtifactsMap tagArtifactsMap;
     foreach (Artifact *artifact, artifacts)
-        foreach (const QString &fileTag, artifact->fileTags)
-            tagArtifactsMap[fileTag].append(artifact);
+        foreach (const FileTag &fileTag, artifact->fileTags)
+            tagArtifactsMap[fileTag.toString()].append(artifact);
 
     QScriptValue jsTagFiles = scriptEngine->newObject();
     for (TagArtifactsMap::const_iterator tag = tagArtifactsMap.constBegin(); tag != tagArtifactsMap.constEnd(); ++tag) {
@@ -91,8 +91,9 @@ void Transformer::setupInputs(QScriptEngine *scriptEngine, QScriptValue targetSc
     targetScriptValue.setProperty("inputs", scriptValue);
     if (inputs.count() == 1) {
         Artifact *input = *inputs.begin();
-        const QSet<QString> &fileTags = input->fileTags;
-        QScriptValue inputsForFileTag = scriptValue.property(*fileTags.begin());
+        const FileTags &fileTags = input->fileTags;
+        QBS_ASSERT(!fileTags.isEmpty(), return);
+        QScriptValue inputsForFileTag = scriptValue.property(fileTags.begin()->toString());
         QScriptValue inputScriptValue = inputsForFileTag.property(0);
         targetScriptValue.setProperty("input", inputScriptValue);
     }
@@ -105,9 +106,9 @@ void Transformer::setupOutputs(QScriptEngine *scriptEngine, QScriptValue targetS
     targetScriptValue.setProperty("outputs", scriptValue);
     if (outputs.count() == 1) {
         Artifact *output = *outputs.begin();
-        const QSet<QString> &fileTags = output->fileTags;
+        const FileTags &fileTags = output->fileTags;
         QBS_ASSERT(!fileTags.isEmpty(), return);
-        QScriptValue outputsForFileTag = scriptValue.property(*fileTags.begin());
+        QScriptValue outputsForFileTag = scriptValue.property(fileTags.begin()->toString());
         QScriptValue outputScriptValue = outputsForFileTag.property(0);
         targetScriptValue.setProperty("output", outputScriptValue);
     }
diff --git a/src/lib/language/artifactproperties.h b/src/lib/language/artifactproperties.h
index 64a853729..eba29d071 100644
--- a/src/lib/language/artifactproperties.h
+++ b/src/lib/language/artifactproperties.h
@@ -42,8 +42,8 @@ class ArtifactProperties : public PersistentObject
 public:
     static ArtifactPropertiesPtr create();
 
-    void setFileTagsFilter(const QStringList &filter) { m_fileTagsFilter = filter; }
-    QStringList fileTagsFilter() const { return m_fileTagsFilter; }
+    void setFileTagsFilter(const FileTags &filter) { m_fileTagsFilter = filter; }
+    FileTags fileTagsFilter() const { return m_fileTagsFilter; }
 
     PropertyMapPtr propertyMap() const { return m_propertyMap; }
     void setPropertyMap(const PropertyMapPtr &pmap) { m_propertyMap = pmap; }
@@ -54,7 +54,7 @@ private:
     void load(PersistentPool &);
     void store(PersistentPool &) const;
 
-    QStringList m_fileTagsFilter;
+    FileTags m_fileTagsFilter;
     PropertyMapPtr m_propertyMap;
 };
 
diff --git a/src/lib/language/filetags.cpp b/src/lib/language/filetags.cpp
new file mode 100644
index 000000000..c7c12b642
--- /dev/null
+++ b/src/lib/language/filetags.cpp
@@ -0,0 +1,95 @@
+/****************************************************************************
+**
+** Copyright (C) 2013 Digia Plc and/or its subsidiary(-ies).
+** Contact: http://www.qt-project.org/legal
+**
+** This file is part of the Qt Build Suite.
+**
+** 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 "filetags.h"
+#include <QStringList>
+
+namespace qbs {
+namespace Internal {
+
+void FileTag::clear()
+{
+    Id::operator=(Id());
+}
+
+QStringList FileTags::toStringList() const
+{
+    QStringList strlst;
+    foreach (const FileTag &tag, *this)
+        strlst += tag.toString();
+    return strlst;
+}
+
+FileTags FileTags::fromStringList(const QStringList &strings)
+{
+    FileTags result;
+    foreach (const QString &str, strings)
+        result += FileTag(str.toLocal8Bit());
+    return result;
+}
+
+LogWriter operator <<(LogWriter w, const FileTags &tags)
+{
+    bool firstLoop = true;
+    w.write('(');
+    foreach (const FileTag &tag, tags) {
+        if (firstLoop)
+            firstLoop = false;
+        else
+            w.write(QLatin1String(", "));
+        w.write(tag.toString());
+    }
+    w.write(')');
+    return w;
+}
+
+QDataStream &operator >>(QDataStream &s, FileTags &tags)
+{
+    int i;
+    s >> i;
+    tags.clear();
+    tags.reserve(i);
+    QVariant v;
+    while (--i >= 0) {
+        s >> v;
+        tags += FileTag::fromSetting(v);
+    }
+    return s;
+}
+
+QDataStream &operator <<(QDataStream &s, const FileTags &tags)
+{
+    s << tags.count();
+    foreach (const FileTag &ft, tags)
+        s << ft.toSetting();
+    return s;
+}
+
+} // namespace Internal
+} // namespace qbs
diff --git a/src/lib/language/filetags.h b/src/lib/language/filetags.h
new file mode 100644
index 000000000..cebdc84b0
--- /dev/null
+++ b/src/lib/language/filetags.h
@@ -0,0 +1,78 @@
+/****************************************************************************
+**
+** Copyright (C) 2013 Digia Plc and/or its subsidiary(-ies).
+** Contact: http://www.qt-project.org/legal
+**
+** This file is part of the Qt Build Suite.
+**
+** 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 QBS_FILETAGS_H
+#define QBS_FILETAGS_H
+
+#include <logging/logger.h>
+#include <tools/id.h>
+#include <QDataStream>
+#include <QSet>
+
+namespace qbs {
+namespace Internal {
+
+class FileTag : public Id
+{
+public:
+    FileTag()
+        : Id()
+    {}
+
+    FileTag(const Id &other)
+        : Id(other)
+    {}
+
+    FileTag(const char *str)
+        : Id(str)
+    {}
+
+    explicit FileTag(const QByteArray &ba)
+        : Id(ba)
+    {}
+
+    void clear();
+};
+
+class FileTags : public QSet<FileTag>
+{
+public:
+    QStringList toStringList() const;
+    static FileTags fromStringList(const QStringList &strings);
+};
+
+LogWriter operator <<(LogWriter w, const FileTags &tags);
+QDataStream &operator >>(QDataStream &s, FileTags & tags);
+QDataStream &operator <<(QDataStream &s, const FileTags &tags);
+
+} // namespace Internal
+} // namespace qbs
+
+#endif // QBS_FILETAGS_H
+
diff --git a/src/lib/language/language.cpp b/src/lib/language/language.cpp
index 412c00775..145cf3fd4 100644
--- a/src/lib/language/language.cpp
+++ b/src/lib/language/language.cpp
@@ -42,8 +42,6 @@
 #include <QMutexLocker>
 #include <QScriptValue>
 
-#include <algorithm>
-
 QT_BEGIN_NAMESPACE
 inline QDataStream& operator>>(QDataStream &stream, qbs::Internal::JsImport &jsImport)
 {
@@ -151,13 +149,13 @@ void PropertyMap::store(PersistentPool &pool) const
 void FileTagger::load(PersistentPool &pool)
 {
     m_artifactExpression.setPattern(pool.idLoadString());
-    m_fileTags = pool.idLoadStringList();
+    pool.stream() >> m_fileTags;
 }
 
 void FileTagger::store(PersistentPool &pool) const
 {
     pool.storeString(m_artifactExpression.pattern());
-    pool.storeStringList(m_fileTags);
+    pool.stream() << m_fileTags;
 }
 
 /*!
@@ -345,16 +343,15 @@ void ResolvedModule::store(PersistentPool &pool) const
 
 QString Rule::toString() const
 {
-    return "[" + inputs.join(",") + " -> " + outputFileTags().join(",") + "]";
+    return QLatin1Char('[') + inputs.toStringList().join(QLatin1String(",")) + QLatin1String(" -> ")
+            + outputFileTags().toStringList().join(QLatin1String(",")) + QLatin1Char(']');
 }
 
-QStringList Rule::outputFileTags() const
+FileTags Rule::outputFileTags() const
 {
-    QStringList result;
+    FileTags result;
     foreach (const RuleArtifactConstPtr &artifact, artifacts)
-        result.append(artifact->fileTags);
-    result.sort();
-    std::unique(result.begin(), result.end());
+        result.unite(artifact->fileTags);
     return result;
 }
 
@@ -419,12 +416,12 @@ QList<SourceArtifactPtr> ResolvedProduct::allEnabledFiles() const
     return lst;
 }
 
-QSet<QString> ResolvedProduct::fileTagsForFileName(const QString &fileName) const
+FileTags ResolvedProduct::fileTagsForFileName(const QString &fileName) const
 {
-    QSet<QString> result;
+    FileTags result;
     foreach (FileTaggerConstPtr tagger, fileTaggers) {
         if (FileInfo::globMatches(tagger->artifactExpression(), fileName)) {
-            result.unite(tagger->fileTags().toSet());
+            result.unite(tagger->fileTags());
         }
     }
     return result;
diff --git a/src/lib/language/language.h b/src/lib/language/language.h
index 79a37c217..9f52f2aee 100644
--- a/src/lib/language/language.h
+++ b/src/lib/language/language.h
@@ -30,6 +30,7 @@
 #ifndef QBS_L2_LANGUAGE_HPP
 #define QBS_L2_LANGUAGE_HPP
 
+#include "filetags.h"
 #include "forward_decls.h"
 #include "jsimports.h"
 #include <tools/codelocation.h>
@@ -86,15 +87,15 @@ class FileTagger : public PersistentObject
 {
 public:
     static FileTaggerPtr create() { return FileTaggerPtr(new FileTagger); }
-    static FileTaggerPtr create(const QRegExp &artifactExpression, const QStringList &fileTags) {
+    static FileTaggerPtr create(const QRegExp &artifactExpression, const FileTags &fileTags) {
         return FileTaggerPtr(new FileTagger(artifactExpression, fileTags));
     }
 
     const QRegExp &artifactExpression() const { return m_artifactExpression; }
-    const QStringList &fileTags() const { return m_fileTags; }
+    const FileTags &fileTags() const { return m_fileTags; }
 
 private:
-    FileTagger(const QRegExp &artifactExpression, const QStringList &fileTags)
+    FileTagger(const QRegExp &artifactExpression, const FileTags &fileTags)
         : m_artifactExpression(artifactExpression), m_fileTags(fileTags)
     { }
 
@@ -106,7 +107,7 @@ private:
     void store(PersistentPool &) const;
 
     QRegExp m_artifactExpression;
-    QStringList m_fileTags;
+    FileTags m_fileTags;
 };
 
 class RuleArtifact : public PersistentObject
@@ -115,7 +116,7 @@ public:
     static RuleArtifactPtr create() { return RuleArtifactPtr(new RuleArtifact); }
 
     QString fileName;
-    QStringList fileTags;
+    FileTags fileTags;
     bool alwaysUpdated;
 
     class Binding
@@ -143,7 +144,7 @@ public:
     static SourceArtifactPtr create() { return SourceArtifactPtr(new SourceArtifact); }
 
     QString absoluteFilePath;
-    QSet<QString> fileTags;
+    FileTags fileTags;
     bool overrideFileTags;
     PropertyMapPtr properties;
 
@@ -257,9 +258,9 @@ public:
     ResolvedModuleConstPtr module;
     JsImports jsImports;
     PrepareScriptConstPtr script;
-    QStringList inputs;
-    QStringList usings;
-    QStringList explicitlyDependsOn;
+    FileTags inputs;
+    FileTags usings;
+    FileTags explicitlyDependsOn;
     bool multiplex;
     QList<RuleArtifactConstPtr> artifacts;
 
@@ -267,7 +268,7 @@ public:
     int ruleGraphId;
 
     QString toString() const;
-    QStringList outputFileTags() const;
+    FileTags outputFileTags() const;
 
 private:
     Rule() : multiplex(false), ruleGraphId(-1) {}
@@ -304,8 +305,8 @@ public:
     ~ResolvedProduct();
 
     bool enabled;
-    QStringList fileTags;
-    QStringList additionalFileTags;
+    FileTags fileTags;
+    FileTags additionalFileTags;
     QString name;
     QString targetName;
     QString sourceDirectory;
@@ -327,7 +328,7 @@ public:
 
     QList<SourceArtifactPtr> allFiles() const;
     QList<SourceArtifactPtr> allEnabledFiles() const;
-    QSet<QString> fileTagsForFileName(const QString &fileName) const;
+    FileTags fileTagsForFileName(const QString &fileName) const;
     void setupBuildEnvironment(ScriptEngine *scriptEngine, const QProcessEnvironment &env) const;
     void setupRunEnvironment(ScriptEngine *scriptEngine, const QProcessEnvironment &env) const;
 
diff --git a/src/lib/language/language.pri b/src/lib/language/language.pri
index 9f9fbeb20..cd0759e81 100644
--- a/src/lib/language/language.pri
+++ b/src/lib/language/language.pri
@@ -1,6 +1,7 @@
 HEADERS += \
     $$PWD/artifactproperties.h \
     $$PWD/evaluationobject.h \
+    $$PWD/filetags.h \
     $$PWD/forward_decls.h \
     $$PWD/identifiersearch.h \
     $$PWD/jsimports.h \
@@ -20,6 +21,7 @@ HEADERS += \
 SOURCES += \
     $$PWD/artifactproperties.cpp \
     $$PWD/evaluationobject.cpp \
+    $$PWD/filetags.cpp \
     $$PWD/identifiersearch.cpp \
     $$PWD/language.cpp \
     $$PWD/languagebasics.cpp \
diff --git a/src/lib/language/loader.cpp b/src/lib/language/loader.cpp
index 313628839..1c7ca9ed5 100644
--- a/src/lib/language/loader.cpp
+++ b/src/lib/language/loader.cpp
@@ -31,6 +31,7 @@
 
 #include "artifactproperties.h"
 #include "evaluationobject.h"
+#include "filetags.h"
 #include "identifiersearch.h"
 #include "language.h"
 #include "languageobject.h"
@@ -237,19 +238,19 @@ static const QLatin1String name_PropertyOptions("PropertyOptions");
 static const QLatin1String name_Depends("Depends");
 static const QLatin1String name_moduleSearchPaths("moduleSearchPaths");
 static const QLatin1String name_Probe("Probe");
-static const uint hashName_FileTagger = qHash(name_FileTagger);
-static const uint hashName_Rule = qHash(name_Rule);
-static const uint hashName_Transformer = qHash(name_Transformer);
-static const uint hashName_Artifact = qHash(name_Artifact);
-static const uint hashName_Group = qHash(name_Group);
-static const uint hashName_Project = qHash(name_Project);
-static const uint hashName_Product = qHash(name_Product);
-static const uint hashName_ProductModule = qHash(name_ProductModule);
-static const uint hashName_Module = qHash(name_Module);
-static const uint hashName_Properties = qHash(name_Properties);
-static const uint hashName_PropertyOptions = qHash(name_PropertyOptions);
-static const uint hashName_Depends = qHash(name_Depends);
-static const uint hashName_Probe = qHash(name_Probe);
+static const uint hashName_FileTagger = qHash(QString(name_FileTagger));
+static const uint hashName_Rule = qHash(QString(name_Rule));
+static const uint hashName_Transformer = qHash(QString(name_Transformer));
+static const uint hashName_Artifact = qHash(QString(name_Artifact));
+static const uint hashName_Group = qHash(QString(name_Group));
+static const uint hashName_Project = qHash(QString(name_Project));
+static const uint hashName_Product = qHash(QString(name_Product));
+static const uint hashName_ProductModule = qHash(QString(name_ProductModule));
+static const uint hashName_Module = qHash(QString(name_Module));
+static const uint hashName_Properties = qHash(QString(name_Properties));
+static const uint hashName_PropertyOptions = qHash(QString(name_PropertyOptions));
+static const uint hashName_Depends = qHash(QString(name_Depends));
+static const uint hashName_Probe = qHash(QString(name_Probe));
 static const QLatin1String name_productPropertyScope("product property scope");
 static const QLatin1String name_projectPropertyScope("project property scope");
 
@@ -1460,10 +1461,10 @@ void Loader::LoaderPrivate::applyFileTaggers(const SourceArtifactPtr &artifact,
                                              const ResolvedProductConstPtr &product)
 {
     if (!artifact->overrideFileTags || artifact->fileTags.isEmpty()) {
-        QSet<QString> fileTags = product->fileTagsForFileName(artifact->absoluteFilePath);
+        FileTags fileTags = product->fileTagsForFileName(artifact->absoluteFilePath);
         artifact->fileTags.unite(fileTags);
         if (artifact->fileTags.isEmpty())
-            artifact->fileTags.insert(QLatin1String("unknown-file-tag"));
+            artifact->fileTags.insert("unknown-file-tag");
         if (m_logger.traceEnabled()) {
             m_logger.qbsTrace() << "[LDR] adding file tags " << artifact->fileTags << " to "
                                 << FileInfo::fileName(artifact->absoluteFilePath);
@@ -1559,11 +1560,9 @@ void Loader::LoaderPrivate::resolveModule(ResolvedProductPtr rproduct, const QSt
     rmodule->jsImports = module->instantiatingObject()->file->jsImports;
     rmodule->setupBuildEnvironmentScript = module->scope->verbatimValue("setupBuildEnvironment");
     rmodule->setupRunEnvironmentScript = module->scope->verbatimValue("setupRunEnvironment");
-    QStringList additionalProductFileTags = module->scope->stringListValue("additionalProductFileTags");
-    if (!additionalProductFileTags.isEmpty()) {
-        rproduct->additionalFileTags.append(additionalProductFileTags);
-        rproduct->additionalFileTags = rproduct->additionalFileTags.toSet().toList();
-    }
+    rproduct->additionalFileTags.unite(
+                FileTags::fromStringList(
+                    module->scope->stringListValue("additionalProductFileTags")));
     foreach (Module::Ptr m, module->modules)
         rmodule->moduleDependencies.append(m->name);
     rproduct->modules.append(rmodule);
@@ -1578,7 +1577,7 @@ void Loader::LoaderPrivate::resolveModule(ResolvedProductPtr rproduct, const QSt
 static void createSourceArtifact(const ResolvedProductConstPtr &rproduct,
                                  const PropertyMapPtr &properties,
                                  const QString &fileName,
-                                 const QSet<QString> &fileTags,
+                                 const FileTags &fileTags,
                                  bool overrideTags,
                                  QList<SourceArtifactPtr> &artifactList)
 {
@@ -1620,7 +1619,8 @@ void Loader::LoaderPrivate::resolveGroup(ResolvedProductPtr rproduct, Evaluation
             properties->setValue(evaluateModuleValues(rproduct, product, group->scope));
         }
 
-        const QStringList fileTagsFilter = group->scope->stringListValue("fileTagsFilter");
+        const FileTags fileTagsFilter
+                = FileTags::fromStringList(group->scope->stringListValue("fileTagsFilter"));
         if (!fileTagsFilter.isEmpty()) {
             if (!files.isEmpty())
                 throw Error(Tr::tr("Group.files and Group.fileTagsFilters are exclusive."),
@@ -1664,9 +1664,9 @@ void Loader::LoaderPrivate::resolveGroup(ResolvedProductPtr rproduct, Evaluation
                     files[i].prepend(prefix);
         }
     }
-    QSet<QString> fileTags;
+    FileTags fileTags;
     if (isGroup)
-        fileTags = group->scope->stringListValue("fileTags").toSet();
+        fileTags = FileTags::fromStringList(group->scope->stringListValue("fileTags"));
     bool overrideTags = true;
     if (isGroup)
         overrideTags = group->scope->boolValue("overrideTags", true);
@@ -1745,7 +1745,7 @@ void Loader::LoaderPrivate::resolveTransformer(ResolvedProductPtr rproduct, Eval
             throw Error(Tr::tr("Artifact fileName must not be empty."));
         artifact->absoluteFilePath = FileInfo::resolvePath(rproduct->project->buildDirectory,
                                                            fileName);
-        artifact->fileTags = child->scope->stringListValue("fileTags").toSet();
+        artifact->fileTags = FileTags::fromStringList(child->scope->stringListValue("fileTags"));
         rtrafo->outputs += artifact;
     }
     rproduct->transformers += rtrafo;
@@ -1817,7 +1817,7 @@ RulePtr Loader::LoaderPrivate::resolveRule(EvaluationObject *object, ResolvedMod
             RuleArtifactPtr artifact = RuleArtifact::create();
             artifacts.append(artifact);
             artifact->fileName = child->scope->verbatimValue("fileName");
-            artifact->fileTags = child->scope->stringListValue("fileTags");
+            artifact->fileTags = FileTags::fromStringList(child->scope->stringListValue("fileTags"));
             artifact->alwaysUpdated = child->scope->boolValue("alwaysUpdated", true);
             if (artifact->alwaysUpdated)
                 hasAlwaysUpdatedArtifact = true;
@@ -1856,9 +1856,10 @@ RulePtr Loader::LoaderPrivate::resolveRule(EvaluationObject *object, ResolvedMod
     rule->script = prepareScript;
     rule->artifacts = artifacts;
     rule->multiplex = object->scope->boolValue("multiplex", false);
-    rule->inputs = object->scope->stringListValue("inputs");
-    rule->usings = object->scope->stringListValue("usings");
-    rule->explicitlyDependsOn = object->scope->stringListValue("explicitlyDependsOn");
+    rule->inputs = FileTags::fromStringList(object->scope->stringListValue("inputs"));
+    rule->usings = FileTags::fromStringList(object->scope->stringListValue("usings"));
+    rule->explicitlyDependsOn = FileTags::fromStringList(
+                object->scope->stringListValue("explicitlyDependsOn"));
     rule->module = module;
 
     return rule;
@@ -1868,7 +1869,7 @@ FileTaggerConstPtr Loader::LoaderPrivate::resolveFileTagger(EvaluationObject *ev
 {
     const Scope::Ptr scope = evaluationObject->scope;
     return FileTagger::create(QRegExp(scope->stringValue("pattern")),
-            scope->stringListValue("fileTags"));
+            FileTags::fromStringList(scope->stringListValue("fileTags")));
 }
 
 /// --------------------------------------------------------------------------
@@ -2532,7 +2533,7 @@ void Loader::LoaderPrivate::resolveProduct(const ResolvedProductPtr &rproduct,
         productProps->properties.insert("buildDirectory", p);
     }
 
-    rproduct->fileTags = productProps->stringListValue("type");
+    rproduct->fileTags = FileTags::fromStringList(productProps->stringListValue("type"));
     rproduct->destinationDirectory = productProps->stringValue("destination");
     foreach (const RulePtr &rule, globalRules)
         rproduct->rules.insert(rule);
diff --git a/src/lib/language/tst_language.cpp b/src/lib/language/tst_language.cpp
index 875216ece..2a185079e 100644
--- a/src/lib/language/tst_language.cpp
+++ b/src/lib/language/tst_language.cpp
@@ -683,7 +683,7 @@ void TestLanguage::fileTags()
     QVERIFY(group);
     QCOMPARE(group->files.count(), 1);
     SourceArtifactConstPtr sourceFile = group->files.first();
-    QStringList fileTags = sourceFile->fileTags.toList();
+    QStringList fileTags = sourceFile->fileTags.toStringList();
     fileTags.sort();
     QCOMPARE(fileTags, expectedFileTags);
 }
diff --git a/src/lib/tools/id.cpp b/src/lib/tools/id.cpp
index 3b85d7bcf..052a9ed9c 100644
--- a/src/lib/tools/id.cpp
+++ b/src/lib/tools/id.cpp
@@ -161,13 +161,13 @@ Id::Id(const QByteArray &name)
    : m_id(theId(name))
 {}
 
-/*!
-    \overload
-    \deprecated
-*/
-Id::Id(const QString &name)
-   : m_id(theId(name.toUtf8()))
-{}
+///*!
+//    \overload
+//    \deprecated
+//*/
+//Id::Id(const QString &name)
+//   : m_id(theId(name.toUtf8()))
+//{}
 
 /*!
   Returns an internal representation of the id.
diff --git a/src/lib/tools/id.h b/src/lib/tools/id.h
index a8990b294..d40416a80 100644
--- a/src/lib/tools/id.h
+++ b/src/lib/tools/id.h
@@ -45,7 +45,7 @@ public:
     Id() : m_id(0) {}
     Id(int uid) : m_id(uid) {}
     Id(const char *name);
-    explicit Id(const QString &name);
+//    explicit Id(const QString &name);
     explicit Id(const QByteArray &name);
 
     Id withSuffix(int suffix) const;
diff --git a/src/lib/tools/persistence.cpp b/src/lib/tools/persistence.cpp
index 40b5a5688..0206118df 100644
--- a/src/lib/tools/persistence.cpp
+++ b/src/lib/tools/persistence.cpp
@@ -39,7 +39,7 @@
 namespace qbs {
 namespace Internal {
 
-static const char QBS_PERSISTENCE_MAGIC[] = "QBSPERSISTENCE0_0_1__31";
+static const char QBS_PERSISTENCE_MAGIC[] = "QBSPERSISTENCE0_0_1__32";
 
 PersistentPool::PersistentPool(const Logger &logger) : m_logger(logger)
 {
diff --git a/src/lib/tools/scannerpluginmanager.cpp b/src/lib/tools/scannerpluginmanager.cpp
index 52aec9879..3f6830b0c 100644
--- a/src/lib/tools/scannerpluginmanager.cpp
+++ b/src/lib/tools/scannerpluginmanager.cpp
@@ -49,7 +49,7 @@ ScannerPluginManager::ScannerPluginManager()
 {
 }
 
-QList<ScannerPlugin *> ScannerPluginManager::scannersForFileTag(const QString &fileTag)
+QList<ScannerPlugin *> ScannerPluginManager::scannersForFileTag(const FileTag &fileTag)
 {
     return instance()->m_scannerPlugins.value(fileTag);
 }
@@ -96,7 +96,7 @@ void ScannerPluginManager::loadPlugins(const QStringList &pluginPaths, const Log
                     "loaded.").arg(QDir::toNativeSeparators(fileName));
 
             for (int i = 0; plugins[i] != 0; ++i)
-                m_scannerPlugins[QString::fromLocal8Bit(plugins[i]->fileTag)] += plugins[i];
+                m_scannerPlugins[FileTag(plugins[i]->fileTag)] += plugins[i];
             m_libs.append(lib.take());
         }
     }
diff --git a/src/lib/tools/scannerpluginmanager.h b/src/lib/tools/scannerpluginmanager.h
index 4ea9107a4..ea0cea92c 100644
--- a/src/lib/tools/scannerpluginmanager.h
+++ b/src/lib/tools/scannerpluginmanager.h
@@ -30,9 +30,10 @@
 #ifndef QBS_PLUGINS_H
 #define QBS_PLUGINS_H
 
+#include <language/filetags.h>
 #include <plugins/scanner/scanner.h>
 
-#include <QMap>
+#include <QHash>
 #include <QString>
 
 QT_BEGIN_NAMESPACE
@@ -47,7 +48,7 @@ class ScannerPluginManager
 {
 public:
     static ScannerPluginManager *instance();
-    static QList<ScannerPlugin *> scannersForFileTag(const QString &fileTag);
+    static QList<ScannerPlugin *> scannersForFileTag(const FileTag &fileTag);
     void loadPlugins(const QStringList &paths, const Logger &logger);
 
 private:
@@ -55,7 +56,7 @@ private:
 
 private:
     QList<QLibrary *> m_libs;
-    QMap<QString, QList<ScannerPlugin*> > m_scannerPlugins;
+    QHash<FileTag, QList<ScannerPlugin*> > m_scannerPlugins;
 };
 
 } // namespace Internal