Implement DownloadLocation retrieving using SHGetKnownFolderPath

This patch implements the TODO concerning the retrieval of
DownloadLocation using SHGetKnownFolderPath

[ChangeLog][QtCore][Windows] Now QStandardPaths::DownloadLocation
returns the proper path for Windows Vista and up

Task-number: QTBUG-35194
Change-Id: Ifc7686e23de76dbfd7826a75e4bf99aa5b9268b0
Reviewed-by: Jan Arve Sæther <jan-arve.saether@digia.com>

1 files changed, 24 insertions, 1 deletions

diff --git a/src/corelib/io/qstandardpaths_win.cpp b/src/corelib/io/qstandardpaths_win.cpp
index a0344a0206..62da5ea245 100644
--- a/src/corelib/io/qstandardpaths_win.cpp
+++ b/src/corelib/io/qstandardpaths_win.cpp
@@ -49,6 +49,10 @@
 #include <qcoreapplication.h>
 #endif
 
+#if !defined(Q_OS_WINCE)
+const GUID qCLSID_FOLDERID_Downloads = { 0x374de290, 0x123f, 0x4565, { 0x91, 0x64,  0x39,  0xc4,  0x92,  0x5e,  0x46,  0x7b } };
+#endif
+
 #include <qt_windows.h>
 #include <shlobj.h>
 #if !defined(Q_OS_WINCE)
@@ -68,6 +72,10 @@
 
 QT_BEGIN_NAMESPACE
 
+#if !defined(Q_OS_WINCE)
+typedef HRESULT (WINAPI *GetKnownFolderPath)(REFKNOWNFOLDERID, DWORD, HANDLE, LPWSTR*);
+#endif
+
 static QString convertCharArray(const wchar_t *path)
 {
     return QDir::fromNativeSeparators(QString::fromWCharArray(path));
@@ -77,6 +85,10 @@ QString QStandardPaths::writableLocation(StandardLocation type)
 {
     QString result;
 
+#if !defined(Q_OS_WINCE)
+    static GetKnownFolderPath SHGetKnownFolderPath = (GetKnownFolderPath)QSystemLibrary::resolve(QLatin1String("shell32"), "SHGetKnownFolderPath");
+#endif
+
     wchar_t path[MAX_PATH];
 
     switch (type) {
@@ -107,7 +119,18 @@ QString QStandardPaths::writableLocation(StandardLocation type)
             result = convertCharArray(path);
         break;
 
-    case DownloadLocation: // TODO implement with SHGetKnownFolderPath(FOLDERID_Downloads) (starting from Vista)
+    case DownloadLocation:
+#if !defined(Q_OS_WINCE)
+        if (SHGetKnownFolderPath) {
+            LPWSTR path;
+            if (SHGetKnownFolderPath(qCLSID_FOLDERID_Downloads, 0, 0, &path) == S_OK) {
+                result = convertCharArray(path);
+                CoTaskMemFree(path);
+            }
+            break;
+        }
+#endif
+        // fall through
     case DocumentsLocation:
         if (SHGetSpecialFolderPath(0, path, CSIDL_PERSONAL, FALSE))
             result = convertCharArray(path);