Implement QFileSystemEngine::createLink() on MS-Win

Fixes: QTBUG-74271
Change-Id: I9e414dd16546f65e85b5a1a6c70c40dfa4284a6f
Reviewed-by: Qt CI Bot <qt_ci_bot@qt-project.org>
Reviewed-by: Volker Hilsheimer <volker.hilsheimer@qt.io>
Reviewed-by: Edward Welbourne <edward.welbourne@qt.io>
Reviewed-by: Oliver Wolff <oliver.wolff@qt.io>

3 files changed, 42 insertions, 49 deletions

diff --git a/src/corelib/io/qfilesystemengine_win.cpp b/src/corelib/io/qfilesystemengine_win.cpp
index 6fa6ec2dc2..6c4418a83b 100644
--- a/src/corelib/io/qfilesystemengine_win.cpp
+++ b/src/corelib/io/qfilesystemengine_win.cpp
@@ -1313,12 +1313,40 @@ QFileSystemEntry QFileSystemEngine::currentPath()
 //static
 bool QFileSystemEngine::createLink(const QFileSystemEntry &source, const QFileSystemEntry &target, QSystemError &error)
 {
-    Q_ASSERT(false);
-    Q_UNUSED(source);
-    Q_UNUSED(target);
-    Q_UNUSED(error);
+    bool ret = false;
+    IShellLink *psl = nullptr;
+    HRESULT hres = CoCreateInstance(CLSID_ShellLink, nullptr, CLSCTX_INPROC_SERVER, IID_IShellLink,
+                                    reinterpret_cast<void **>(&psl));
 
-    return false; // TODO implement; - code needs to be moved from qfsfileengine_win.cpp
+    bool neededCoInit = false;
+    if (hres == CO_E_NOTINITIALIZED) { // COM was not initialized
+        neededCoInit = true;
+        CoInitialize(nullptr);
+        hres = CoCreateInstance(CLSID_ShellLink, nullptr, CLSCTX_INPROC_SERVER, IID_IShellLink,
+                                reinterpret_cast<void **>(&psl));
+    }
+
+    if (SUCCEEDED(hres)) {
+        const auto name = QDir::toNativeSeparators(source.filePath());
+        const auto pathName = QDir::toNativeSeparators(source.path());
+        if (SUCCEEDED(psl->SetPath(reinterpret_cast<const wchar_t *>(name.utf16())))
+            && SUCCEEDED(psl->SetWorkingDirectory(reinterpret_cast<const wchar_t *>(pathName.utf16())))) {
+            IPersistFile *ppf = nullptr;
+            if (SUCCEEDED(psl->QueryInterface(IID_IPersistFile, reinterpret_cast<void **>(&ppf)))) {
+                ret = SUCCEEDED(ppf->Save(reinterpret_cast<const wchar_t *>(target.filePath().utf16()), TRUE));
+                ppf->Release();
+            }
+        }
+        psl->Release();
+    }
+
+    if (!ret)
+        error = QSystemError(::GetLastError(), QSystemError::NativeError);
+
+    if (neededCoInit)
+        CoUninitialize();
+
+    return ret;
 }
 
 //static
diff --git a/src/corelib/io/qfsfileengine.cpp b/src/corelib/io/qfsfileengine.cpp
index 1a1a9076c7..cef5a1f3e7 100644
--- a/src/corelib/io/qfsfileengine.cpp
+++ b/src/corelib/io/qfsfileengine.cpp
@@ -981,7 +981,10 @@ QString QFSFileEngine::tempPath()
   Creates a link from the file currently specified by fileName() to
   \a newName. What a link is depends on the underlying filesystem
   (be it a shortcut on Windows or a symbolic link on Unix). Returns
-  true if successful; otherwise returns \c false.
+  \c true if successful; otherwise returns \c false.
+
+  \note On Windows \a newName is expected to end with .lnk as the filename
+  extension.
 */
 
 
diff --git a/src/corelib/io/qfsfileengine_win.cpp b/src/corelib/io/qfsfileengine_win.cpp
index 84ba42f55a..fad9f5e48b 100644
--- a/src/corelib/io/qfsfileengine_win.cpp
+++ b/src/corelib/io/qfsfileengine_win.cpp
@@ -494,52 +494,14 @@ bool QFSFileEnginePrivate::doStat(QFileSystemMetaData::MetaDataFlags flags) cons
     return metaData.exists();
 }
 
-
+// ### assume that they add .lnk to newName
 bool QFSFileEngine::link(const QString &newName)
 {
-    bool ret = false;
-
-    QString linkName = newName;
-    //### assume that they add .lnk
-
-    IShellLink *psl;
-    bool neededCoInit = false;
-
-    HRESULT hres = CoCreateInstance(CLSID_ShellLink, nullptr, CLSCTX_INPROC_SERVER, IID_IShellLink,
-                                    reinterpret_cast<void **>(&psl));
-
-    if (hres == CO_E_NOTINITIALIZED) { // COM was not initialized
-        neededCoInit = true;
-        CoInitialize(nullptr);
-        hres = CoCreateInstance(CLSID_ShellLink, nullptr, CLSCTX_INPROC_SERVER, IID_IShellLink,
-                                reinterpret_cast<void **>(&psl));
-    }
-
-    if (SUCCEEDED(hres)) {
-        const QString nativeAbsoluteName = fileName(AbsoluteName).replace(QLatin1Char('/'), QLatin1Char('\\'));
-        hres = psl->SetPath(reinterpret_cast<const wchar_t *>(nativeAbsoluteName.utf16()));
-        if (SUCCEEDED(hres)) {
-            const QString nativeAbsolutePathName = fileName(AbsolutePathName).replace(QLatin1Char('/'), QLatin1Char('\\'));
-            hres = psl->SetWorkingDirectory(reinterpret_cast<const wchar_t *>(nativeAbsolutePathName.utf16()));
-            if (SUCCEEDED(hres)) {
-                IPersistFile *ppf;
-                hres = psl->QueryInterface(IID_IPersistFile, reinterpret_cast<void **>(&ppf));
-                if (SUCCEEDED(hres)) {
-                    hres = ppf->Save(reinterpret_cast<const wchar_t *>(linkName.utf16()), TRUE);
-                    if (SUCCEEDED(hres))
-                         ret = true;
-                    ppf->Release();
-                }
-            }
-        }
-        psl->Release();
-    }
+    QSystemError error;
+    bool ret = QFileSystemEngine::createLink(QFileSystemEntry(fileName(AbsoluteName)),
+                                             QFileSystemEntry(newName), error);
     if (!ret)
-        setError(QFile::RenameError, qt_error_string());
-
-    if (neededCoInit)
-        CoUninitialize();
-
+        setError(QFile::RenameError, error.toString());
     return ret;
 }