Add libproxy backend for QNetworkProxyFactory

It will be used on Unix systems if the required dev package is
present. (Detected by a configure compile test.)
You can configure with -no-libproxy to avoid the dependency.
It will not be used on OS X or Windows, as we already implement
the native API for getting proxies there.

Currently we use whatever PAC runner is provided by the distro
for running PAC scripts - if we want to run PAC scripts using
Qt, then we would have to implement a pacrunner plugin to libproxy.
Note that their webkit pacrunner is using javascriptcore already.

Tested using the libproxy 0.4.7 that is included in Ubuntu 12.04.
Re-tested using Ubuntu 14.04 which ships libproxy 0.4.11.

It works except when both socks and http proxies are configured in
the manual settings - in that case libproxy returns only the socks
proxy. This seems to be covered by libproxy issue 119.

[ChangeLog][QtNetwork] Introduce libproxy backend for Unix platforms,
enabled automatically if the required dev package is present

Task-number: QTBUG-26295
Change-Id: I521c0a198fcf482386ea8a189114a0077778265c
Reviewed-by: Richard J. Moore <rich@kde.org>

2 files changed, 63 insertions, 0 deletions

diff --git a/config.tests/common/libproxy/libproxy.cpp b/config.tests/common/libproxy/libproxy.cpp
new file mode 100644
index 0000000000..cd366f52ee
--- /dev/null
+++ b/config.tests/common/libproxy/libproxy.cpp
@@ -0,0 +1,59 @@
+/****************************************************************************
+**
+** Copyright (C) 2015 Digia Plc and/or its subsidiary(-ies).
+** Contact: http://www.qt-project.org/legal
+**
+** This file is part of the config.tests of the Qt Toolkit.
+**
+** $QT_BEGIN_LICENSE:LGPL$
+** Commercial License Usage
+** Licensees holding valid commercial Qt licenses may use this file in
+** accordance with the commercial license agreement provided with the
+** Software or, alternatively, in accordance with the terms contained in
+** a written agreement between you and Digia.  For licensing terms and
+** conditions see http://qt.digia.com/licensing.  For further information
+** use the contact form at http://qt.digia.com/contact-us.
+**
+** GNU Lesser General Public License Usage
+** Alternatively, this file may be used under the terms of the GNU Lesser
+** General Public License version 2.1 as published by the Free Software
+** Foundation and appearing in the file LICENSE.LGPL included in the
+** packaging of this file.  Please review the following information to
+** ensure the GNU Lesser General Public License version 2.1 requirements
+** will be met: http://www.gnu.org/licenses/old-licenses/lgpl-2.1.html.
+**
+** In addition, as a special exception, Digia gives you certain additional
+** rights.  These rights are described in the Digia Qt LGPL Exception
+** version 1.1, included in the file LGPL_EXCEPTION.txt in this package.
+**
+** GNU General Public License Usage
+** Alternatively, this file may be used under the terms of the GNU
+** General Public License version 3.0 as published by the Free Software
+** Foundation and appearing in the file LICENSE.GPL included in the
+** packaging of this file.  Please review the following information to
+** ensure the GNU General Public License version 3.0 requirements will be
+** met: http://www.gnu.org/copyleft/gpl.html.
+**
+**
+** $QT_END_LICENSE$
+**
+****************************************************************************/
+
+#include <stdio.h>
+#include <stdlib.h>
+#include <proxy.h>
+
+int main(int, char **)
+{
+    pxProxyFactory *factory = px_proxy_factory_new();
+    char **proxies = px_proxy_factory_get_proxies(factory, "http://qt-project.org");
+    if (proxies) {
+        for (int i = 0; proxies[i]; i++) {
+            printf("%s\n", proxies[i]);
+            free(proxies[i]);
+        }
+        free(proxies);
+    }
+    px_proxy_factory_free(factory);
+    return 0;
+}
diff --git a/config.tests/common/libproxy/libproxy.pro b/config.tests/common/libproxy/libproxy.pro
new file mode 100644
index 0000000000..51de2021ff
--- /dev/null
+++ b/config.tests/common/libproxy/libproxy.pro
@@ -0,0 +1,4 @@
+SOURCES = libproxy.cpp
+CONFIG -= qt dylib
+mac:CONFIG -= app_bundle
+LIBS += -lproxy