Unify behavior for long path or UNC prefix removal

Split the code out of QDir::fromNativeSeparator into a separate
reusable function to remove the above-mentioned prefixes. Fixes
and unifies behavior if the prefix was given with slashes instead
of backslashes. Add a couple more test cases.

Fixes: QTBUG-93868
Change-Id: Ibd94ae283e2fb113f9c2db97475fbc7d89522bbf
Reviewed-by: Edward Welbourne <edward.welbourne@qt.io>
Reviewed-by: Oliver Wolff <oliver.wolff@qt.io>
(cherry picked from commit 0564ebdb3641d7325f73dbbf2cbb04e6dca92d83)

5 files changed, 67 insertions, 6 deletions

diff --git a/tests/auto/corelib/io/qdir/tst_qdir.cpp b/tests/auto/corelib/io/qdir/tst_qdir.cpp
index cec01eb752..d43e45e12f 100644
--- a/tests/auto/corelib/io/qdir/tst_qdir.cpp
+++ b/tests/auto/corelib/io/qdir/tst_qdir.cpp
@@ -1268,9 +1268,20 @@ tst_QDir::cleanPath_data()
     QTest::newRow("drive-above-root") << "A:/.." << "A:/..";
     QTest::newRow("unc-server-up") << "//server/path/.." << "//server";
     QTest::newRow("unc-server-above-root") << "//server/.." << "//server/..";
+
     QTest::newRow("longpath") << "\\\\?\\d:\\" << "d:/";
+    QTest::newRow("longpath-slash") << "//?/d:/" << "d:/";
+    QTest::newRow("longpath-mixed-slashes") << "//?/d:\\" << "d:/";
+    QTest::newRow("longpath-mixed-slashes-2") << "\\\\?\\d:/" << "d:/";
+
     QTest::newRow("unc-network-share") << "\\\\?\\UNC\\localhost\\c$\\tmp.txt"
         << "//localhost/c$/tmp.txt";
+    QTest::newRow("unc-network-share-slash") << "//?/UNC/localhost/c$/tmp.txt"
+        << "//localhost/c$/tmp.txt";
+    QTest::newRow("unc-network-share-mixed-slashes") << "//?/UNC/localhost\\c$\\tmp.txt"
+        << "//localhost/c$/tmp.txt";
+    QTest::newRow("unc-network-share-mixed-slashes-2") << "\\\\?\\UNC\\localhost/c$/tmp.txt"
+        << "//localhost/c$/tmp.txt";
 #else
     QTest::newRow("data15") << "//c:/foo" << "/c:/foo";
 #endif // non-windows
@@ -1748,6 +1759,8 @@ void tst_QDir::nativeSeparators()
     QCOMPARE(QDir::fromNativeSeparators(QLatin1String("\\\\?\\C:\\")), QString("C:/"));
     QCOMPARE(QDir::fromNativeSeparators(QLatin1String(R"(\\?\UNC\localhost\c$\tmp.txt)")),
              QString("//localhost/c$/tmp.txt"));
+    QCOMPARE(QDir::fromNativeSeparators(QLatin1String(R"(//?/UNC/localhost\c$\tmp.txt)")),
+             QString("//localhost/c$/tmp.txt"));
 #else
     QCOMPARE(QDir::toNativeSeparators(QLatin1String("/")), QString("/"));
     QCOMPARE(QDir::toNativeSeparators(QLatin1String("\\")), QString("\\"));
diff --git a/tests/auto/corelib/io/qtemporarydir/CMakeLists.txt b/tests/auto/corelib/io/qtemporarydir/CMakeLists.txt
index fa8efa114b..fcfd409d5b 100644
--- a/tests/auto/corelib/io/qtemporarydir/CMakeLists.txt
+++ b/tests/auto/corelib/io/qtemporarydir/CMakeLists.txt
@@ -10,3 +10,8 @@ qt_internal_add_test(tst_qtemporarydir
     PUBLIC_LIBRARIES
         Qt::TestPrivate
 )
+
+qt_internal_extend_target(tst_qtemporarydir CONDITION WIN32
+    LIBRARIES
+        shlwapi
+)
diff --git a/tests/auto/corelib/io/qtemporarydir/tst_qtemporarydir.cpp b/tests/auto/corelib/io/qtemporarydir/tst_qtemporarydir.cpp
index 14f3a10593..94fcc006bb 100644
--- a/tests/auto/corelib/io/qtemporarydir/tst_qtemporarydir.cpp
+++ b/tests/auto/corelib/io/qtemporarydir/tst_qtemporarydir.cpp
@@ -37,6 +37,7 @@
 #include <qset.h>
 #include <QtTest/private/qtesthelpers_p.h>
 #ifdef Q_OS_WIN
+# include <shlwapi.h>
 # include <windows.h>
 #endif
 #ifdef Q_OS_UNIX // for geteuid()
@@ -159,9 +160,25 @@ void tst_QTemporaryDir::fileTemplate_data()
     }
 
 #ifdef Q_OS_WIN
-    const auto tmp = QDir::toNativeSeparators(QDir::tempPath()).sliced(QDir::rootPath().size());
-    QTest::newRow("UNC") << "\\\\localhost\\C$\\" + tmp + "\\UNC.XXXXXX.tmpDir"
-                         << "UNC." << ".tmpDir";
+    auto tmp = QDir::toNativeSeparators(QDir::tempPath());
+    if (PathGetDriveNumber((const wchar_t *) tmp.utf16()) < 0)
+        return; // skip if we have no drive letter
+
+    tmp.data()[1] = u'$';
+    const auto tmpPath = tmp + QLatin1String(R"(\UNC.XXXXXX.tmpDir)");
+
+    QTest::newRow("UNC-backslash")
+            << "\\\\localhost\\" + tmpPath << "UNC."
+            << ".tmpDir";
+    QTest::newRow("UNC-prefix")
+            << "\\\\?\\UNC\\localhost\\" + tmpPath << "UNC."
+            << ".tmpDir";
+    QTest::newRow("UNC-slash")
+            << "//localhost/" + QDir::fromNativeSeparators(tmpPath) << "UNC."
+            << ".tmpDir";
+    QTest::newRow("UNC-prefix-slash")
+            << "//?/UNC/localhost/" + QDir::fromNativeSeparators(tmpPath) << "UNC."
+            << ".tmpDir";
 #endif
 }
 
diff --git a/tests/auto/corelib/io/qtemporaryfile/CMakeLists.txt b/tests/auto/corelib/io/qtemporaryfile/CMakeLists.txt
index 11d4b991ce..f8419cee87 100644
--- a/tests/auto/corelib/io/qtemporaryfile/CMakeLists.txt
+++ b/tests/auto/corelib/io/qtemporaryfile/CMakeLists.txt
@@ -45,3 +45,8 @@ if(ANDROID AND NOT ANDROID_EMBEDDED)
             ${android_testdata_resource_files}
     )
 endif()
+
+qt_internal_extend_target(tst_qtemporaryfile CONDITION WIN32
+    LIBRARIES
+        shlwapi
+)
diff --git a/tests/auto/corelib/io/qtemporaryfile/tst_qtemporaryfile.cpp b/tests/auto/corelib/io/qtemporaryfile/tst_qtemporaryfile.cpp
index e23df1da2b..7071f2142e 100644
--- a/tests/auto/corelib/io/qtemporaryfile/tst_qtemporaryfile.cpp
+++ b/tests/auto/corelib/io/qtemporaryfile/tst_qtemporaryfile.cpp
@@ -40,6 +40,7 @@
 #include <QtTest/private/qtesthelpers_p.h>
 
 #if defined(Q_OS_WIN)
+# include <shlwapi.h>
 # include <windows.h>
 #endif
 #if defined(Q_OS_UNIX)
@@ -208,9 +209,29 @@ void tst_QTemporaryFile::fileTemplate_data()
     }
 
 #ifdef Q_OS_WIN
-    const auto tmp = QDir::toNativeSeparators(QDir::tempPath()).sliced(QDir::rootPath().size());
-    QTest::newRow("UNC") << "\\\\localhost\\C$\\" + tmp + "\\QTBUG-74291.XXXXXX.tmpFile"
-                         << "QTBUG-74291." << ".tmpFile" << "";
+    auto tmp = QDir::toNativeSeparators(QDir::tempPath());
+    if (PathGetDriveNumber((const wchar_t *) tmp.utf16()) < 0)
+        return; // skip if we have no drive letter
+
+    tmp.data()[1] = u'$';
+    const auto tmpPath = tmp + QLatin1String(R"(\QTBUG-74291.XXXXXX.tmpFile)");
+
+    QTest::newRow("UNC-backslash")
+            << "\\\\localhost\\" + tmpPath << "QTBUG-74291."
+            << ".tmpFile"
+            << "";
+    QTest::newRow("UNC-prefix")
+            << "\\\\?\\UNC\\localhost\\" + tmpPath << "QTBUG-74291."
+            << ".tmpFile"
+            << "";
+    QTest::newRow("UNC-slash")
+            << "//localhost/" + QDir::fromNativeSeparators(tmpPath) << "QTBUG-74291."
+            << ".tmpFile"
+            << "";
+    QTest::newRow("UNC-prefix-slash")
+            << "//?/UNC/localhost/" + QDir::fromNativeSeparators(tmpPath) << "QTBUG-74291."
+            << ".tmpFile"
+            << "";
 #endif
 }