Implement QFileInfo::junctionTarget(), adjust auto-test

The change in 004e3e0dc2cab4a4534d2ed3ace41aad6bfbe45d introduces
Windows junction awareness, though users were still unable to resolve
the junction target. This change adds the ability to solve this.

Fixes: QTBUG-93869
Change-Id: I9f4d4ed87b92e757f7b6d8739e2a61b58c096f63
Reviewed-by: Volker Hilsheimer <volker.hilsheimer@qt.io>
Reviewed-by: Edward Welbourne <edward.welbourne@qt.io>
Reviewed-by: Qt CI Bot <qt_ci_bot@qt-project.org>

2 files changed, 30 insertions, 8 deletions

diff --git a/tests/auto/corelib/io/qfileinfo/tst_qfileinfo.cpp b/tests/auto/corelib/io/qfileinfo/tst_qfileinfo.cpp
index 916b084e24..4d74fe4d98 100644
--- a/tests/auto/corelib/io/qfileinfo/tst_qfileinfo.cpp
+++ b/tests/auto/corelib/io/qfileinfo/tst_qfileinfo.cpp
@@ -1782,14 +1782,36 @@ void tst_QFileInfo::ntfsJunctionPointsAndSymlinks()
             }
         }
     });
-    const QString actualSymLinkTarget = isSymLink ? fi.symLinkTarget() : QString();
-    const QString actualCanonicalFilePath = isSymLink ? fi.canonicalFilePath() : QString();
+    const QString actualCanonicalFilePath = fi.canonicalFilePath();
     QCOMPARE(fi.isJunction(), isJunction);
     QCOMPARE(fi.isSymbolicLink(), isSymLink);
     if (isSymLink) {
-        QCOMPARE(actualSymLinkTarget, linkTarget);
+        QCOMPARE(fi.symLinkTarget(), linkTarget);
         QCOMPARE(actualCanonicalFilePath, canonicalFilePath);
     }
+
+    if (isJunction) {
+        if (creationResult.target.startsWith(uR"(\??\)"))
+            creationResult.target = creationResult.target.sliced(4);
+
+        // resolve volume to drive letter
+        static const QRegularExpression matchVolumeRe(uR"(^Volume\{([a-z]|[0-9]|-)+\}\\)"_qs,
+            QRegularExpression::CaseInsensitiveOption);
+        auto matchVolume = matchVolumeRe.match(creationResult.target);
+        if (matchVolume.hasMatch()) {
+            Q_ASSERT(matchVolume.capturedStart() == 0);
+            DWORD len;
+            wchar_t buffer[MAX_PATH];
+            const QString volumeName = uR"(\\?\)"_qs + matchVolume.captured();
+            if (GetVolumePathNamesForVolumeName(reinterpret_cast<LPCWSTR>(volumeName.utf16()),
+                                                buffer, MAX_PATH, &len) != 0) {
+                creationResult.target.replace(0, matchVolume.capturedLength(),
+                                              QString::fromWCharArray(buffer));
+            }
+        }
+        QCOMPARE(fi.junctionTarget(), QDir::fromNativeSeparators(creationResult.target));
+        QCOMPARE(actualCanonicalFilePath, QFileInfo(creationResult.link).canonicalFilePath());
+    }
 }
 
 void tst_QFileInfo::brokenShortcut()
diff --git a/tests/benchmarks/corelib/io/qfileinfo/main.cpp b/tests/benchmarks/corelib/io/qfileinfo/main.cpp
index 65b712898b..2cd06eef27 100644
--- a/tests/benchmarks/corelib/io/qfileinfo/main.cpp
+++ b/tests/benchmarks/corelib/io/qfileinfo/main.cpp
@@ -43,7 +43,7 @@ private slots:
     void existsStatic();
 #if defined(Q_OS_WIN)
     void symLinkTargetPerformanceLNK();
-    void symLinkTargetPerformanceMounpoint();
+    void junctionTargetPerformanceMountpoint();
 #endif
     void initTestCase();
     void cleanupTestCase();
@@ -86,7 +86,7 @@ void qfileinfo::symLinkTargetPerformanceLNK()
     QVERIFY(QFile::remove("link.lnk"));
 }
 
-void qfileinfo::symLinkTargetPerformanceMounpoint()
+void qfileinfo::junctionTargetPerformanceMountpoint()
 {
     wchar_t buffer[MAX_PATH];
     QString rootPath = QDir::toNativeSeparators(QDir::rootPath());
@@ -99,11 +99,11 @@ void qfileinfo::symLinkTargetPerformanceMounpoint()
 
     QFileInfo info(mountpoint);
     info.setCaching(false);
-    QVERIFY(info.isSymLink());
-    QString linkTarget;
+    QVERIFY(info.isJunction());
+    QString junctionTarget;
     QBENCHMARK {
         for(int i=0; i<100; i++)
-            linkTarget = info.symLinkTarget();
+            junctionTarget = info.junctionTarget();
     }
     QVERIFY(QDir().rmdir(mountpoint));
 }