From 324e92417859949b67a7ed4e32c4e2ed6ece734b Mon Sep 17 00:00:00 2001
From: Marcus Tillmanns <marcus.tillmanns@qt.io>
Date: Thu, 10 Aug 2023 06:44:12 +0200
Subject: [PATCH] Utils: Fix FilePath::isRootPath()

Change-Id: I287bae74469ba501ecb03d51f04f7aaa5f4a7268
Reviewed-by: hjk <hjk@qt.io>
---
 src/libs/utils/filepath.cpp                | 32 ++++++++++++++++----
 tests/auto/utils/filepath/tst_filepath.cpp | 35 ++++++++++++++++++++++
 2 files changed, 61 insertions(+), 6 deletions(-)

diff --git a/src/libs/utils/filepath.cpp b/src/libs/utils/filepath.cpp
index 049ae325bd8..3995ddde3a7 100644
--- a/src/libs/utils/filepath.cpp
+++ b/src/libs/utils/filepath.cpp
@@ -204,7 +204,27 @@ FilePath FilePath::currentWorkingPath()
 
 bool FilePath::isRootPath() const
 {
-    // FIXME: Make host-independent
+    if (needsDevice()) {
+        QStringView path = pathView();
+        if (osType() != OsTypeWindows)
+            return path == QLatin1String("/");
+
+        // Remote windows paths look like this: "/c:/", so we remove the leading '/'
+        if (path.startsWith('/'))
+            path = path.mid(1);
+
+        if (path.length() > 3)
+            return false;
+
+        if (!startsWithDriveLetter())
+            return false;
+
+        if (path.length() == 3 && path[2] != QLatin1Char('/'))
+            return false;
+
+        return true;
+    }
+
     return *this == FilePath::fromString(QDir::rootPath());
 }
 
@@ -1346,15 +1366,15 @@ bool FilePath::contains(const QString &s) const
 
 /*!
     \brief Checks whether the FilePath starts with a drive letter.
-
-    Defaults to \c false if it is a non-Windows host or represents a path on device
-
     Returns whether FilePath starts with a drive letter
 */
 bool FilePath::startsWithDriveLetter() const
 {
-    const QStringView p = pathView();
-    return !needsDevice() && p.size() >= 2 && isWindowsDriveLetter(p[0]) && p.at(1) == ':';
+    QStringView p = pathView();
+    if (needsDevice() && !p.isEmpty())
+        p = p.mid(1);
+
+    return p.size() >= 2 && isWindowsDriveLetter(p[0]) && p.at(1) == ':';
 }
 
 /*!
diff --git a/tests/auto/utils/filepath/tst_filepath.cpp b/tests/auto/utils/filepath/tst_filepath.cpp
index f9e10d5e207..6a269af7712 100644
--- a/tests/auto/utils/filepath/tst_filepath.cpp
+++ b/tests/auto/utils/filepath/tst_filepath.cpp
@@ -115,6 +115,8 @@ private slots:
     void sort();
     void sort_data();
 
+    void isRootPath();
+
 private:
     QTemporaryDir tempDir;
     QString rootPath;
@@ -1308,6 +1310,14 @@ void tst_filepath::startsWithDriveLetter_data()
     QTest::newRow("simple-win") << FilePath::fromString("c:/a") << true;
     QTest::newRow("simple-linux") << FilePath::fromString("/c:/a") << false;
     QTest::newRow("relative") << FilePath("a/b") << false;
+
+    QTest::newRow("remote-slash") << FilePath::fromString("docker://1234/") << false;
+    QTest::newRow("remote-single-letter") << FilePath::fromString("docker://1234/c") << false;
+    QTest::newRow("remote-drive") << FilePath::fromString("docker://1234/c:") << true;
+    QTest::newRow("remote-invalid-drive") << FilePath::fromString("docker://1234/c:a") << true;
+    QTest::newRow("remote-with-path") << FilePath::fromString("docker://1234/c:/a") << true;
+    QTest::newRow("remote-z") << FilePath::fromString("docker://1234/z:") << true;
+    QTest::newRow("remote-1") << FilePath::fromString("docker://1234/1:") << false;
 }
 
 void tst_filepath::startsWithDriveLetter()
@@ -1656,6 +1666,31 @@ void tst_filepath::sort()
     QCOMPARE(sortedPaths, sorted);
 }
 
+void tst_filepath::isRootPath()
+{
+    FilePath localRoot = FilePath::fromString(QDir::rootPath());
+    QVERIFY(localRoot.isRootPath());
+
+    FilePath localNonRoot = FilePath::fromString(QDir::rootPath() + "x");
+    QVERIFY(!localNonRoot.isRootPath());
+
+    if (HostOsInfo::isWindowsHost()) {
+        FilePath remoteWindowsRoot = FilePath::fromString("device://test/c:/");
+        QVERIFY(remoteWindowsRoot.isRootPath());
+
+        FilePath remoteWindowsRoot1 = FilePath::fromString("device://test/c:");
+        QVERIFY(remoteWindowsRoot1.isRootPath());
+
+        FilePath remoteWindowsNotRoot = FilePath::fromString("device://test/c:/x");
+        QVERIFY(!remoteWindowsNotRoot.isRootPath());
+    } else {
+        FilePath remoteRoot = FilePath::fromString("device://test/");
+        QVERIFY(remoteRoot.isRootPath());
+
+        FilePath remotePath = FilePath::fromString("device://test/x");
+        QVERIFY(!remotePath.isRootPath());
+    }
+}
 void tst_filepath::sort_data()
 {
     QTest::addColumn<QStringList>("input");