Windows: Don't output a warning when sHGetKnownFolderPath fails

In the rare case where the known locations for the standard paths are
not known (such as when an application is used without a user logged
in), it will output a warning to indicate this. In the case of the
GenericConfigLocation, this can mean that it will hang due to the fact
that QLoggingCategory is looking for that location too before it can
output anything.

Therefore, the warning output is removed so that if this part fails it
doesn't cause it to hang as a result.

Change-Id: I4f189361899bd1f868292f30c09fbe50982d2288
Reviewed-by: Kai Koehne <[email protected]>

src/corelib/io/qstandardpaths_win.cpp

@@ -129,7 +129,7 @@ static GUID writableSpecialFolderId(QStandardPaths::StandardLocation type)
 }
 
 // Convenience for SHGetKnownFolderPath().
-static QString sHGetKnownFolderPath(const GUID &clsid, QStandardPaths::StandardLocation type, bool warn = false)
+static QString sHGetKnownFolderPath(const GUID &clsid)
 {
     QString result;
     typedef HRESULT (WINAPI *GetKnownFolderPath)(const GUID&, DWORD, HANDLE, LPWSTR*);
@@ -141,11 +141,6 @@ static QString sHGetKnownFolderPath(const GUID &clsid, QStandardPaths::StandardL
     if (Q_LIKELY(sHGetKnownFolderPath && SUCCEEDED(sHGetKnownFolderPath(clsid, KF_FLAG_DONT_VERIFY, 0, &path)))) {
         result = convertCharArray(path);
         CoTaskMemFree(path);
-    } else {
-        if (warn) {
-            qErrnoWarning("SHGetKnownFolderPath() failed for standard location \"%s\".",
-                          qPrintable(displayName(type)));
-        }
     }
     return result;
 }
@@ -155,7 +150,7 @@ QString QStandardPaths::writableLocation(StandardLocation type)
     QString result;
     switch (type) {
     case DownloadLocation:
-        result = sHGetKnownFolderPath(FOLDERID_Downloads, type);
+        result = sHGetKnownFolderPath(FOLDERID_Downloads);
         if (result.isEmpty())
             result = QStandardPaths::writableLocation(QStandardPaths::DocumentsLocation);
         break;
@@ -164,7 +159,7 @@ QString QStandardPaths::writableLocation(StandardLocation type)
         // Although Microsoft has a Cache key it is a pointer to IE's cache, not a cache
         // location for everyone.  Most applications seem to be using a
         // cache directory located in their AppData directory
-        result = sHGetKnownFolderPath(writableSpecialFolderId(AppLocalDataLocation), type, /* warn */ true);
+        result = sHGetKnownFolderPath(writableSpecialFolderId(AppLocalDataLocation));
         if (!result.isEmpty()) {
             appendTestMode(result);
             appendOrganizationAndApp(result);
@@ -173,7 +168,7 @@ QString QStandardPaths::writableLocation(StandardLocation type)
         break;
 
     case GenericCacheLocation:
-        result = sHGetKnownFolderPath(writableSpecialFolderId(GenericDataLocation), type, /* warn */ true);
+        result = sHGetKnownFolderPath(writableSpecialFolderId(GenericDataLocation));
         if (!result.isEmpty()) {
             appendTestMode(result);
             result += QLatin1String("/cache");
@@ -190,7 +185,7 @@ QString QStandardPaths::writableLocation(StandardLocation type)
         break;
 
     default:
-        result = sHGetKnownFolderPath(writableSpecialFolderId(type), type, /* warn */ isConfigLocation(type));
+        result = sHGetKnownFolderPath(writableSpecialFolderId(type));
         if (!result.isEmpty() && isConfigLocation(type)) {
             appendTestMode(result);
             if (!isGenericConfigLocation(type))
@@ -214,7 +209,7 @@ QStringList QStandardPaths::standardLocations(StandardLocation type)
 
     // type-specific handling goes here
     if (isConfigLocation(type)) {
-        QString programData = sHGetKnownFolderPath(FOLDERID_ProgramData, type);
+        QString programData = sHGetKnownFolderPath(FOLDERID_ProgramData);
         if (!programData.isEmpty()) {
             if (!isGenericConfigLocation(type))
                 appendOrganizationAndApp(programData);