From 1bc5f619ea1cae8cfec2ac53a8206ceb28845c8f Mon Sep 17 00:00:00 2001
From: Friedemann Kleint <Friedemann.Kleint@qt.io>
Date: Tue, 13 Jun 2017 11:45:59 +0200
Subject: QStorageInfo/Windows: Improve error handling

Bail out of QStorageInfoPrivate::doStats() should an error occur
and set the ready/valid flags accordingly.

Task-number: QTBUG-6039
Change-Id: Id5354b31329d951599ae991aa7edde0515c90514
Reviewed-by: Thiago Macieira <thiago.macieira@intel.com>
---
 src/corelib/io/qstorageinfo_win.cpp | 52 ++++++++++++++++++++++++-------------
 1 file changed, 34 insertions(+), 18 deletions(-)

diff --git a/src/corelib/io/qstorageinfo_win.cpp b/src/corelib/io/qstorageinfo_win.cpp
index f02e46f095..3830c5480c 100644
--- a/src/corelib/io/qstorageinfo_win.cpp
+++ b/src/corelib/io/qstorageinfo_win.cpp
@@ -43,36 +43,52 @@
 #include <QtCore/qfileinfo.h>
 #include <QtCore/qvarlengtharray.h>
 
+#include "qfilesystementry_p.h"
+
 #include <qt_windows.h>
 
 QT_BEGIN_NAMESPACE
 
 static const int defaultBufferSize = MAX_PATH + 1;
 
-void QStorageInfoPrivate::initRootPath()
+static QString canonicalPath(const QString &rootPath)
 {
-    rootPath = QFileInfo(rootPath).canonicalFilePath();
-
-    if (rootPath.isEmpty())
-        return;
-
-    QString path = QDir::toNativeSeparators(rootPath);
-    rootPath.clear();
+    QString path = QDir::toNativeSeparators(QFileInfo(rootPath).canonicalFilePath());
+    if (path.isEmpty())
+        return path;
 
     if (path.startsWith(QLatin1String("\\\\?\\")))
         path.remove(0, 4);
     if (path.length() < 2 || path.at(1) != QLatin1Char(':'))
-        return;
+        return QString();
+
     path[0] = path[0].toUpper();
     if (!(path.at(0).unicode() >= 'A' && path.at(0).unicode() <= 'Z'))
-        return;
+        return QString();
     if (!path.endsWith(QLatin1Char('\\')))
         path.append(QLatin1Char('\\'));
+    return path;
+}
+
+void QStorageInfoPrivate::initRootPath()
+{
+    // Do not unnecessarily call QFileInfo::canonicalFilePath() if the path is
+    // already a drive root since it may hang on network drives.
+    const QString path = QFileSystemEntry::isDriveRootPath(rootPath)
+        ? QDir::toNativeSeparators(rootPath)
+        : canonicalPath(rootPath);
+
+    if (path.isEmpty()) {
+        valid = ready = false;
+        return;
+    }
 
     // ### test if disk mounted to folder on other disk
     wchar_t buffer[defaultBufferSize];
     if (::GetVolumePathName(reinterpret_cast<const wchar_t *>(path.utf16()), buffer, defaultBufferSize))
         rootPath = QDir::fromNativeSeparators(QString::fromWCharArray(buffer));
+    else
+        valid = ready = false;
 }
 
 static inline QByteArray getDevice(const QString &rootPath)
@@ -108,11 +124,14 @@ static inline QByteArray getDevice(const QString &rootPath)
 
 void QStorageInfoPrivate::doStat()
 {
+    valid = ready = true;
     initRootPath();
-    if (rootPath.isEmpty())
+    if (!valid || !ready)
         return;
 
     retrieveVolumeInfo();
+    if (!valid || !ready)
+        return;
     device = getDevice(rootPath);
     retrieveDiskFreeSpace();
 }
@@ -137,9 +156,6 @@ void QStorageInfoPrivate::retrieveVolumeInfo()
         ready = false;
         valid = ::GetLastError() == ERROR_NOT_READY;
     } else {
-        ready = true;
-        valid = true;
-
         fileSystemType = QString::fromWCharArray(fileSystemTypeBuffer).toLatin1();
         name = QString::fromWCharArray(nameBuffer);
 
@@ -154,10 +170,10 @@ void QStorageInfoPrivate::retrieveDiskFreeSpace()
     const UINT oldmode = ::SetErrorMode(SEM_FAILCRITICALERRORS | SEM_NOOPENFILEERRORBOX);
 
     const QString path = QDir::toNativeSeparators(rootPath);
-    ::GetDiskFreeSpaceEx(reinterpret_cast<const wchar_t *>(path.utf16()),
-                         PULARGE_INTEGER(&bytesAvailable),
-                         PULARGE_INTEGER(&bytesTotal),
-                         PULARGE_INTEGER(&bytesFree));
+    ready = ::GetDiskFreeSpaceEx(reinterpret_cast<const wchar_t *>(path.utf16()),
+                                 PULARGE_INTEGER(&bytesAvailable),
+                                 PULARGE_INTEGER(&bytesTotal),
+                                 PULARGE_INTEGER(&bytesFree));
 
     ::SetErrorMode(oldmode);
 }
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