qtlsbackend_openssl: optimize QDirListing usage

Internally QDirListing uses the name filters to create
QRegularExpression objects which are then used to do the matching. Here
we are looking for files that have ".pem" or ".crt" extensions, so basic
string matching should work the same and is inherently faster.

Pick-to: 6.9
Change-Id: Ib19b1eb8717b21c3b96a52e7036665c40fb24caf
Reviewed-by: Mårten Nordheim <[email protected]>

1 files changed, 12 insertions, 3 deletions

diff --git a/src/plugins/tls/openssl/qtlsbackend_openssl.cpp b/src/plugins/tls/openssl/qtlsbackend_openssl.cpp
index 15bf384ae86..6a55f275943 100644
--- a/src/plugins/tls/openssl/qtlsbackend_openssl.cpp
+++ b/src/plugins/tls/openssl/qtlsbackend_openssl.cpp
@@ -391,13 +391,22 @@ QList<QSslCertificate> systemCaCertificates()
             QStringLiteral("/etc/pki/tls/certs/ca-bundle.crt"), // Fedora, Mandriva
             QStringLiteral("/usr/local/share/certs/ca-root-nss.crt") // FreeBSD's ca_root_nss
         };
-        static const QStringList nameFilters = {u"*.pem"_s, u"*.crt"_s};
+
+        static const size_t extLen = strlen(".pem"); // or strlen(".crt")
+        auto hasMatchingExtension = [](const QString &fileName) {
+            if (size_t(fileName.size()) < extLen + 1)
+                return false;
+            auto ext = QStringView{fileName}.last(extLen);
+            return ext == ".pem"_L1 || ext == ".crt"_L1;
+        };
+
         using F = QDirListing::IteratorFlag;
         constexpr auto flags = F::FilesOnly | F::ResolveSymlinks; // Files and symlinks to files
         for (const QByteArray &directory : directories) {
-            for (const auto &dirEntry : QDirListing(QFile::decodeName(directory), nameFilters, flags)) {
+            for (const auto &dirEntry : QDirListing(QFile::decodeName(directory), flags)) {
                 // use canonical path here to not load the same certificate twice if symlinked
-                certFiles.insert(dirEntry.canonicalFilePath());
+                if (hasMatchingExtension(dirEntry.fileName()))
+                    certFiles.insert(dirEntry.canonicalFilePath());
             }
         }
         for (const QString& file : std::as_const(certFiles))