ReviveOverlay: Fix assert when using empty credentials.

Author: CrossVR

ReviveOverlay/windowsservices.cpp

@@ -96,7 +96,7 @@ bool WindowsServices::PromptCredentials(QString& user, QString& password, bool f
 pcred.hbmBanner = nullptr;
 DWORD result = CredUIPromptForWindowsCredentialsW(&pcred, failed ? ERROR_LOGON_FAILURE : 0, &pkg, packedAuth.constData(), packedAuth.size(), &authBuffer, &authSize, &save, flags);
 packedAuth.fill(0);
-if (result == NO_ERROR)
+if (result == ERROR_SUCCESS)
 {
 DWORD userSize = 0, passwordSize = 0;
 CredUnPackAuthenticationBufferW(0,
@@ -114,8 +114,8 @@ bool WindowsServices::PromptCredentials(QString& user, QString& password, bool f
 user.resize(userSize - 1);
 password.reserve(passwordSize);
 password.resize(passwordSize - 1);
-Q_ASSERT(user.capacity() == userSize);
-Q_ASSERT(password.capacity() == passwordSize);
+Q_ASSERT(user.capacity() >= userSize);
+Q_ASSERT(password.capacity() >= passwordSize);
 
 CredUnPackAuthenticationBufferW(0,
 authBuffer, authSize,
@@ -149,6 +149,13 @@ bool WindowsServices::ReadCredentials(QString& user, QString& password)
 
 bool WindowsServices::WriteCredentials(const QString& user, const QString& password)
 {
+if (user.isEmpty() && password.isEmpty())
+{
+// Did you mean to do this?
+DeleteCredentials();
+return true;
+}
+
 // We're casting a bunch of const away here, but it should be safe
 CREDENTIALW cred = {0};
 cred.Type = CRED_TYPE_GENERIC;