ClangTools: Cache information about the clazy executable

Fixes: QTCREATORBUG-26237
Change-Id: I43203d58b8ed278664427e3b4112a7c7848354b9
Reviewed-by: David Schulz <david.schulz@qt.io>

src/plugins/clangtools/clangtoolssettings.cpp

@@ -227,7 +227,7 @@ QVersionNumber ClangToolsSettings::clangTidyVersion()
 
 QVersionNumber ClangToolsSettings::clazyVersion()
 {
-    return ClazyStandaloneInfo(ClangTools::Internal::clazyStandaloneExecutable()).version;
+    return ClazyStandaloneInfo::getInfo(ClangTools::Internal::clazyStandaloneExecutable()).version;
 }
 
 } // namespace Internal

src/plugins/clangtools/diagnosticconfigswidget.cpp

@@ -1140,7 +1140,7 @@ QString removeClangTidyCheck(const QString &checks, const QString &check)
 
 QString removeClazyCheck(const QString &checks, const QString &check)
 {
-    const ClazyStandaloneInfo clazyInfo(clazyStandaloneExecutable());
+    const ClazyStandaloneInfo clazyInfo = ClazyStandaloneInfo::getInfo(clazyStandaloneExecutable());
     ClazyChecksTreeModel model(clazyInfo.supportedChecks);
     model.enableChecks(checks.split(',', Qt::SkipEmptyParts));
     const QModelIndex index = model.indexForName(check.mid(QString("clazy-").length()));
@@ -1190,7 +1190,8 @@ void disableChecks(const QList<Diagnostic> &diagnostics)
         if (diag.name.startsWith("clazy-")) {
             if (config.clazyMode() == ClangDiagnosticConfig::ClazyMode::UseDefaultChecks) {
                 config.setClazyMode(ClangDiagnosticConfig::ClazyMode::UseCustomChecks);
-                const ClazyStandaloneInfo clazyInfo(clazyStandaloneExecutable());
+                const ClazyStandaloneInfo clazyInfo
+                        = ClazyStandaloneInfo::getInfo(clazyStandaloneExecutable());
                 config.setClazyChecks(clazyInfo.defaultChecks.join(','));
             }
             config.setClazyChecks(removeClazyCheck(config.clazyChecks(), diag.name));

src/plugins/clangtools/executableinfo.cpp

@@ -163,6 +163,23 @@ ClangTidyInfo::ClangTidyInfo(const QString &executablePath)
     , supportedChecks(queryClangTidyChecks(executablePath, "-checks=*"))
 {}
 
+ClazyStandaloneInfo ClazyStandaloneInfo::getInfo(const QString &_executablePath)
+{
+    const FilePath executablePath = FilePath::fromString(_executablePath);
+    const QDateTime timeStamp = executablePath.lastModified();
+    const auto it = cache.find(executablePath);
+    if (it == cache.end()) {
+        const ClazyStandaloneInfo info(executablePath.toString());
+        cache.insert(executablePath, qMakePair(timeStamp, info));
+        return info;
+    }
+    if (it->first != timeStamp) {
+        it->first = timeStamp;
+        it->second = ClazyStandaloneInfo(executablePath.toString());
+    }
+    return it->second;
+}
+
 ClazyStandaloneInfo::ClazyStandaloneInfo(const QString &executablePath)
     : defaultChecks(queryClangTidyChecks(executablePath, {})) // Yup, behaves as clang-tidy.
     , supportedChecks(querySupportedClazyChecks(executablePath))
@@ -229,5 +246,7 @@ QPair<FilePath, QString> getClangIncludeDirAndVersion(const FilePath &clangToolP
     return qMakePair(dynamicResourceDir + "/include", dynamicVersion);
 }
 
+QHash<Utils::FilePath, QPair<QDateTime, ClazyStandaloneInfo>> ClazyStandaloneInfo::cache;
+
 } // namespace Internal
 } // namespace ClangTools

src/plugins/clangtools/executableinfo.h

@@ -27,6 +27,8 @@
 
 #include <utils/fileutils.h>
 
+#include <QDateTime>
+#include <QHash>
 #include <QPair>
 #include <QStringList>
 #include <QVector>
@@ -60,11 +62,16 @@ using ClazyChecks = QVector<ClazyCheck>;
 class ClazyStandaloneInfo
 {
 public:
-    ClazyStandaloneInfo(const QString &executablePath);
+    static ClazyStandaloneInfo getInfo(const QString &executablePath);
 
     QVersionNumber version;
     QStringList defaultChecks;
     ClazyChecks supportedChecks;
+
+private:
+    ClazyStandaloneInfo(const QString &executablePath);
+
+    static QHash<Utils::FilePath, QPair<QDateTime, ClazyStandaloneInfo>> cache;
 };
 
 } // namespace Internal

src/plugins/clangtools/runsettingswidget.cpp

@@ -80,7 +80,7 @@ static CppTools::ClangDiagnosticConfigsWidget *createEditWidget(
     return new DiagnosticConfigsWidget(configs,
                                        configToSelect,
                                        ClangTidyInfo(clangTidyPath),
-                                       ClazyStandaloneInfo(clazyStandalonePath));
+                                       ClazyStandaloneInfo::getInfo(clazyStandalonePath));
 }
 
 void RunSettingsWidget::fromSettings(const RunSettings &s)