SSL backend: Add a decodeDer() method to the private API

This allows QSslKey to avoid converting to pem format if the backend
supports native der decoding.

Change-Id: I0822a21401ad0ca81c6eeb6c7d53c421e1e2e93a
Reviewed-by: Richard J. Moore <rich@kde.org>

src/network/ssl/qsslkey_openssl.cpp

@@ -109,6 +109,12 @@ bool QSslKeyPrivate::fromEVP_PKEY(EVP_PKEY *pkey)
     return false;
 }
 
+void QSslKeyPrivate::decodeDer(const QByteArray &der, const QByteArray &passPhrase,
+                               bool deepClear)
+{
+    decodePem(pemFromDer(der), passPhrase, deepClear);
+}
+
 void QSslKeyPrivate::decodePem(const QByteArray &pem, const QByteArray &passPhrase,
                                bool deepClear)
 {

src/network/ssl/qsslkey_p.cpp

@@ -189,9 +189,10 @@ QSslKey::QSslKey(const QByteArray &encoded, QSsl::KeyAlgorithm algorithm,
 {
     d->type = type;
     d->algorithm = algorithm;
-    d->decodePem((encoding == QSsl::Der)
-                 ? d->pemFromDer(encoded) : encoded,
-                 passPhrase);
+    if (encoding == QSsl::Der)
+        d->decodeDer(encoded, passPhrase);
+    else
+        d->decodePem(encoded, passPhrase);
 }
 
 /*!

src/network/ssl/qsslkey_p.h

@@ -86,6 +86,8 @@ public:
     void clear(bool deep = true);
 
     bool fromEVP_PKEY(EVP_PKEY *pkey);
+    void decodeDer(const QByteArray &der, const QByteArray &passPhrase,
+                   bool deepClear = true);
     void decodePem(const QByteArray &pem, const QByteArray &passPhrase,
                    bool deepClear = true);
     QByteArray pemHeader() const;