Use std:: containers in ProjectBuildData

It appears, that destruction of complex QHashes/QLists took a bit time
in refcounts. Optimize them by using std::unordered_map and std::vector
instead. Plus, make structure simplier, instead of 2 hashes, use pair as
a key.

qbs::Internal::ProjectBuildData::~ProjectBuildData()
Before: 11.00 ms    0.1%
After:   6.00 ms    0.0%

Change-Id: I82d8bec5a465210cfa54762088f47c606c0e48e5
Reviewed-by: Denis Shienkov <denis.shienkov@gmail.com>
Reviewed-by: Christian Kandeler <christian.kandeler@qt.io>

6 files changed, 33 insertions, 26 deletions

diff --git a/src/lib/corelib/buildgraph/buildgraph.cpp b/src/lib/corelib/buildgraph/buildgraph.cpp
index 616658a18..283e8dc2a 100644
--- a/src/lib/corelib/buildgraph/buildgraph.cpp
+++ b/src/lib/corelib/buildgraph/buildgraph.cpp
@@ -572,13 +572,10 @@ Artifact *lookupArtifact(const ResolvedProductConstPtr &product,
         const ProjectBuildData *projectBuildData, const QString &dirPath, const QString &fileName,
         bool compareByName)
 {
-    const QList<FileResourceBase *> lookupResults
-            = projectBuildData->lookupFiles(dirPath, fileName);
-    for (QList<FileResourceBase *>::const_iterator it = lookupResults.constBegin();
-            it != lookupResults.constEnd(); ++it) {
-        if ((*it)->fileType() != FileResourceBase::FileTypeArtifact)
+    for (const auto &fileResource : projectBuildData->lookupFiles(dirPath, fileName)) {
+        if (fileResource->fileType() != FileResourceBase::FileTypeArtifact)
             continue;
-        auto artifact = static_cast<Artifact *>(*it);
+        const auto artifact = static_cast<Artifact *>(fileResource);
         if (compareByName
                 ? artifact->product->uniqueName() == product->uniqueName()
                 : artifact->product == product) {
diff --git a/src/lib/corelib/buildgraph/executor.cpp b/src/lib/corelib/buildgraph/executor.cpp
index 930c1698e..de81ada20 100644
--- a/src/lib/corelib/buildgraph/executor.cpp
+++ b/src/lib/corelib/buildgraph/executor.cpp
@@ -243,8 +243,7 @@ void Executor::doBuild()
     const QStringList &filesToConsider = m_buildOptions.filesToConsider();
     if (!filesToConsider.empty()) {
         for (const QString &fileToConsider : filesToConsider) {
-            const QList<FileResourceBase *> &files
-                    = m_project->buildData->lookupFiles(fileToConsider);
+            const auto &files = m_project->buildData->lookupFiles(fileToConsider);
             for (const FileResourceBase * const file : files) {
                 if (file->fileType() != FileResourceBase::FileTypeArtifact)
                     continue;
@@ -838,7 +837,7 @@ void Executor::rescueOldBuildData(Artifact *artifact, bool *childrenAdded = null
                 childrenToConnect.push_back(child);
         }
         for (const QString &depPath : rad.fileDependencies) {
-            const QList<FileResourceBase *> depList = m_project->buildData->lookupFiles(depPath);
+            const auto &depList = m_project->buildData->lookupFiles(depPath);
             if (depList.empty()) {
                 canRescue = false;
                 qCDebug(lcBuildGraph) << "File dependency" << depPath
diff --git a/src/lib/corelib/buildgraph/projectbuilddata.cpp b/src/lib/corelib/buildgraph/projectbuilddata.cpp
index 6a145dacc..31012e23e 100644
--- a/src/lib/corelib/buildgraph/projectbuilddata.cpp
+++ b/src/lib/corelib/buildgraph/projectbuilddata.cpp
@@ -96,8 +96,7 @@ QString ProjectBuildData::deriveBuildGraphFilePath(const QString &buildDir, cons
 
 void ProjectBuildData::insertIntoLookupTable(FileResourceBase *fileres)
 {
-    QList<FileResourceBase *> &lst
-            = m_artifactLookupTable[fileres->fileName()][fileres->dirPath()];
+    auto &lst = m_artifactLookupTable[{fileres->fileName(), fileres->dirPath()}];
     const auto * const artifact = fileres->fileType() == FileResourceBase::FileTypeArtifact
             ? static_cast<Artifact *>(fileres) : nullptr;
     if (artifact && artifact->artifactType == Artifact::Generated) {
@@ -117,30 +116,32 @@ void ProjectBuildData::insertIntoLookupTable(FileResourceBase *fileres)
             throw error;
         }
     }
-    QBS_CHECK(!lst.contains(fileres));
+    QBS_CHECK(!contains(lst, fileres));
     lst.push_back(fileres);
     m_isDirty = true;
 }
 
 void ProjectBuildData::removeFromLookupTable(FileResourceBase *fileres)
 {
-    m_artifactLookupTable[fileres->fileName()][fileres->dirPath()].removeOne(fileres);
+    removeOne(m_artifactLookupTable[{fileres->fileName(), fileres->dirPath()}], fileres);
 }
 
-QList<FileResourceBase *> ProjectBuildData::lookupFiles(const QString &filePath) const
+const std::vector<FileResourceBase *> &ProjectBuildData::lookupFiles(const QString &filePath) const
 {
     QString dirPath, fileName;
     FileInfo::splitIntoDirectoryAndFileName(filePath, &dirPath, &fileName);
     return lookupFiles(dirPath, fileName);
 }
 
-QList<FileResourceBase *> ProjectBuildData::lookupFiles(const QString &dirPath,
+const std::vector<FileResourceBase *> &ProjectBuildData::lookupFiles(const QString &dirPath,
         const QString &fileName) const
 {
-    return m_artifactLookupTable.value(fileName).value(dirPath);
+    static const std::vector<FileResourceBase *> emptyResult;
+    const auto it = m_artifactLookupTable.find({fileName, dirPath});
+    return it != m_artifactLookupTable.end() ? it->second : emptyResult;
 }
 
-QList<FileResourceBase *> ProjectBuildData::lookupFiles(const Artifact *artifact) const
+const std::vector<FileResourceBase *> &ProjectBuildData::lookupFiles(const Artifact *artifact) const
 {
     return lookupFiles(artifact->dirPath(), artifact->fileName());
 }
diff --git a/src/lib/corelib/buildgraph/projectbuilddata.h b/src/lib/corelib/buildgraph/projectbuilddata.h
index 49101a716..930344435 100644
--- a/src/lib/corelib/buildgraph/projectbuilddata.h
+++ b/src/lib/corelib/buildgraph/projectbuilddata.h
@@ -45,13 +45,15 @@
 #include <logging/logger.h>
 #include <tools/persistence.h>
 #include <tools/set.h>
+#include <tools/qttools.h>
 
-#include <QtCore/qhash.h>
 #include <QtCore/qlist.h>
 #include <QtCore/qstring.h>
 
 #include <QtScript/qscriptvalue.h>
 
+#include <unordered_map>
+
 namespace qbs {
 namespace Internal {
 class BuildGraphNode;
@@ -70,9 +72,9 @@ public:
     void insertIntoLookupTable(FileResourceBase *fileres);
     void removeFromLookupTable(FileResourceBase *fileres);
 
-    QList<FileResourceBase *> lookupFiles(const QString &filePath) const;
-    QList<FileResourceBase *> lookupFiles(const QString &dirPath, const QString &fileName) const;
-    QList<FileResourceBase *> lookupFiles(const Artifact *artifact) const;
+    const std::vector<FileResourceBase *> &lookupFiles(const QString &filePath) const;
+    const std::vector<FileResourceBase *> &lookupFiles(const QString &dirPath, const QString &fileName) const;
+    const std::vector<FileResourceBase *> &lookupFiles(const Artifact *artifact) const;
     void insertFileDependency(FileDependency *dependency);
     void removeArtifactAndExclusiveDependents(Artifact *artifact, const Logger &logger,
             bool removeFromProduct = true, ArtifactSet *removedArtifacts = nullptr);
@@ -99,9 +101,10 @@ private:
         pool.serializationOp<opType>(fileDependencies, rawScanResults);
     }
 
-    using ResultsPerDirectory = QHash<QString, QList<FileResourceBase *>>;
-    using ArtifactLookupTable = QHash<QString, ResultsPerDirectory>;
+    using ArtifactKey = std::pair<QString /*fileName*/, QString /*dirName*/>;
+    using ArtifactLookupTable = std::unordered_map<ArtifactKey, std::vector<FileResourceBase *>>;
     ArtifactLookupTable m_artifactLookupTable;
+
     bool m_doCleanupInDestructor = true;
     bool m_isDirty = true;
 };
diff --git a/src/lib/corelib/buildgraph/transformerchangetracking.cpp b/src/lib/corelib/buildgraph/transformerchangetracking.cpp
index eadc99272..505f0cbba 100644
--- a/src/lib/corelib/buildgraph/transformerchangetracking.cpp
+++ b/src/lib/corelib/buildgraph/transformerchangetracking.cpp
@@ -226,8 +226,7 @@ const Artifact *TrafoChangeTracker::getArtifact(const QString &filePath,
     const ResolvedProduct * const product = getProduct(productName);
     if (!product)
         return nullptr;
-    const QList<FileResourceBase *> &candidates
-            = product->topLevelProject()->buildData->lookupFiles(filePath);
+    const auto &candidates = product->topLevelProject()->buildData->lookupFiles(filePath);
     const Artifact *artifact = nullptr;
     for (const FileResourceBase * const candidate : candidates) {
         if (candidate->fileType() == FileResourceBase::FileTypeArtifact) {
diff --git a/src/lib/corelib/tools/qttools.h b/src/lib/corelib/tools/qttools.h
index 2252c12d3..4cb39527e 100644
--- a/src/lib/corelib/tools/qttools.h
+++ b/src/lib/corelib/tools/qttools.h
@@ -53,7 +53,15 @@ namespace std {
 template<> struct hash<QString> {
     std::size_t operator()(const QString &s) const { return qHash(s); }
 };
-}
+
+template<typename T1, typename T2> struct hash<std::pair<T1, T2>>
+{
+    size_t operator()(const pair<T1, T2> &x) const
+    {
+        return std::hash<T1>()(x.first) ^ std::hash<T2>()(x.second);
+    }
+};
+} // namespace std
 
 QT_BEGIN_NAMESPACE
 uint qHash(const QStringList &list);