[Shader Graph Gen.] Introduce QShaderNodesLoader

This class allows to node definitions from a JSON representation. This
will come in handy to ship preset prototypes for use with
QShaderGraphLoader.

Change-Id: I3f3b5d7852e17d484069b4814ee6e5910997c613
Reviewed-by: Sean Harmer <sean.harmer@kdab.com>

3 files changed, 341 insertions, 2 deletions

diff --git a/src/gui/util/qshadernodesloader.cpp b/src/gui/util/qshadernodesloader.cpp
new file mode 100644
index 0000000000..83472d664b
--- /dev/null
+++ b/src/gui/util/qshadernodesloader.cpp
@@ -0,0 +1,242 @@
+/****************************************************************************
+**
+** Copyright (C) 2017 Klaralvdalens Datakonsult AB (KDAB).
+** Contact: https://www.qt.io/licensing/
+**
+** This file is part of the QtGui module 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 The Qt Company. For licensing terms
+** and conditions see https://www.qt.io/terms-conditions. For further
+** information use the contact form at https://www.qt.io/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 3 as published by the Free Software
+** Foundation and appearing in the file LICENSE.LGPL3 included in the
+** packaging of this file. Please review the following information to
+** ensure the GNU Lesser General Public License version 3 requirements
+** will be met: https://www.gnu.org/licenses/lgpl-3.0.html.
+**
+** GNU General Public License Usage
+** Alternatively, this file may be used under the terms of the GNU
+** General Public License version 2.0 or (at your option) the GNU General
+** Public license version 3 or any later version approved by the KDE Free
+** Qt Foundation. The licenses are as published by the Free Software
+** Foundation and appearing in the file LICENSE.GPL2 and LICENSE.GPL3
+** included in the packaging of this file. Please review the following
+** information to ensure the GNU General Public License requirements will
+** be met: https://www.gnu.org/licenses/gpl-2.0.html and
+** https://www.gnu.org/licenses/gpl-3.0.html.
+**
+** $QT_END_LICENSE$
+**
+****************************************************************************/
+
+#include "qshadernodesloader_p.h"
+
+#include <QtCore/qdebug.h>
+#include <QtCore/qiodevice.h>
+#include <QtCore/qjsonarray.h>
+#include <QtCore/qjsondocument.h>
+#include <QtCore/qjsonobject.h>
+
+QT_BEGIN_NAMESPACE
+
+QShaderNodesLoader::QShaderNodesLoader() Q_DECL_NOTHROW
+    : m_status(Null),
+      m_device(nullptr)
+{
+}
+
+QShaderNodesLoader::Status QShaderNodesLoader::status() const Q_DECL_NOTHROW
+{
+    return m_status;
+}
+
+QHash<QString, QShaderNode> QShaderNodesLoader::nodes() const Q_DECL_NOTHROW
+{
+    return m_nodes;
+}
+
+QIODevice *QShaderNodesLoader::device() const Q_DECL_NOTHROW
+{
+    return m_device;
+}
+
+void QShaderNodesLoader::setDevice(QIODevice *device) Q_DECL_NOTHROW
+{
+    m_device = device;
+    m_nodes.clear();
+    m_status = !m_device ? Null
+             : (m_device->openMode() & QIODevice::ReadOnly) ? Waiting
+             : Error;
+}
+
+void QShaderNodesLoader::load()
+{
+    if (m_status == Error)
+        return;
+
+    auto error = QJsonParseError();
+    const auto document = QJsonDocument::fromJson(m_device->readAll(), &error);
+
+    if (error.error != QJsonParseError::NoError) {
+        qWarning() << "Invalid JSON document:" << error.errorString();
+        m_status = Error;
+        return;
+    }
+
+    if (document.isEmpty() || !document.isObject()) {
+        qWarning() << "Invalid JSON document, root should be an object";
+        m_status = Error;
+        return;
+    }
+
+    const auto root = document.object();
+
+    bool hasError = false;
+
+    for (const auto &property : root.keys()) {
+        const auto nodeValue = root.value(property);
+        if (!nodeValue.isObject()) {
+            qWarning() << "Invalid node found";
+            hasError = true;
+            break;
+        }
+
+        const auto nodeObject = nodeValue.toObject();
+
+        auto node = QShaderNode();
+
+        const auto inputsValue = nodeObject.value(QStringLiteral("inputs"));
+        if (inputsValue.isArray()) {
+            const auto inputsArray = inputsValue.toArray();
+            for (const auto &inputValue : inputsArray) {
+                if (!inputValue.isString()) {
+                    qWarning() << "Non-string value in inputs";
+                    hasError = true;
+                    break;
+                }
+
+                auto input = QShaderNodePort();
+                input.direction = QShaderNodePort::Input;
+                input.name = inputValue.toString();
+                node.addPort(input);
+            }
+        }
+
+        const auto outputsValue = nodeObject.value(QStringLiteral("outputs"));
+        if (outputsValue.isArray()) {
+            const auto outputsArray = outputsValue.toArray();
+            for (const auto &outputValue : outputsArray) {
+                if (!outputValue.isString()) {
+                    qWarning() << "Non-string value in outputs";
+                    hasError = true;
+                    break;
+                }
+
+                auto output = QShaderNodePort();
+                output.direction = QShaderNodePort::Output;
+                output.name = outputValue.toString();
+                node.addPort(output);
+            }
+        }
+
+        const auto rulesValue = nodeObject.value(QStringLiteral("rules"));
+        if (rulesValue.isArray()) {
+            const auto rulesArray = rulesValue.toArray();
+            for (const auto &ruleValue : rulesArray) {
+                if (!ruleValue.isObject()) {
+                    qWarning() << "Rules should be objects";
+                    hasError = true;
+                    break;
+                }
+
+                const auto ruleObject = ruleValue.toObject();
+
+                const auto formatValue = ruleObject.value(QStringLiteral("format"));
+                if (!formatValue.isObject()) {
+                    qWarning() << "Format is mandatory in rules and should be an object";
+                    hasError = true;
+                    break;
+                }
+
+                const auto formatObject = formatValue.toObject();
+                auto format = QShaderFormat();
+
+                const auto apiValue = formatObject.value(QStringLiteral("api"));
+                if (!apiValue.isString()) {
+                    qWarning() << "Format API must be a string";
+                    hasError = true;
+                    break;
+                }
+
+                const auto api = apiValue.toString();
+                format.setApi(api == QStringLiteral("OpenGLES") ? QShaderFormat::OpenGLES
+                            : api == QStringLiteral("OpenGLNoProfile") ? QShaderFormat::OpenGLNoProfile
+                            : api == QStringLiteral("OpenGLCoreProfile") ? QShaderFormat::OpenGLCoreProfile
+                            : api == QStringLiteral("OpenGLCompatibilityProfile") ? QShaderFormat::OpenGLCompatibilityProfile
+                            : QShaderFormat::NoApi);
+                if (format.api() == QShaderFormat::NoApi) {
+                    qWarning() << "Format API must be one of: OpenGLES, OpenGLNoProfile, OpenGLCoreProfile or OpenGLCompatibilityProfile";
+                    hasError = true;
+                    break;
+                }
+
+                const auto majorValue = formatObject.value(QStringLiteral("major"));
+                const auto minorValue = formatObject.value(QStringLiteral("minor"));
+                if (!majorValue.isDouble() || !minorValue.isDouble()) {
+                    qWarning() << "Format major and minor version must be values";
+                    hasError = true;
+                    break;
+                }
+                format.setVersion(QVersionNumber(majorValue.toInt(), minorValue.toInt()));
+
+                const auto extensionsValue = formatObject.value(QStringLiteral("extensions"));
+                const auto extensionsArray = extensionsValue.toArray();
+                auto extensions = QStringList();
+                std::transform(extensionsArray.constBegin(), extensionsArray.constEnd(),
+                               std::back_inserter(extensions),
+                               [] (const QJsonValue &extensionValue) { return extensionValue.toString(); });
+                format.setExtensions(extensions);
+
+                const auto vendor = formatObject.value(QStringLiteral("vendor")).toString();
+                format.setVendor(vendor);
+
+                const auto substitutionValue = ruleObject.value(QStringLiteral("substitution"));
+                if (!substitutionValue.isString()) {
+                    qWarning() << "Substitution needs to be a string";
+                    hasError = true;
+                    break;
+                }
+
+                const auto substitution = substitutionValue.toString().toUtf8();
+
+                const auto snippetsValue = ruleObject.value(QStringLiteral("headerSnippets"));
+                const auto snippetsArray = snippetsValue.toArray();
+                auto snippets = QByteArrayList();
+                std::transform(snippetsArray.constBegin(), snippetsArray.constEnd(),
+                               std::back_inserter(snippets),
+                               [] (const QJsonValue &snippetValue) { return snippetValue.toString().toUtf8(); });
+
+                node.addRule(format, QShaderNode::Rule(substitution, snippets));
+            }
+        }
+
+        m_nodes.insert(property, node);
+    }
+
+    if (hasError) {
+        m_status = Error;
+        m_nodes.clear();
+    } else {
+        m_status = Ready;
+    }
+}
+
+QT_END_NAMESPACE
diff --git a/src/gui/util/qshadernodesloader_p.h b/src/gui/util/qshadernodesloader_p.h
new file mode 100644
index 0000000000..2696e958b6
--- /dev/null
+++ b/src/gui/util/qshadernodesloader_p.h
@@ -0,0 +1,95 @@
+/****************************************************************************
+**
+** Copyright (C) 2017 Klaralvdalens Datakonsult AB (KDAB).
+** Contact: https://www.qt.io/licensing/
+**
+** This file is part of the QtGui module 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 The Qt Company. For licensing terms
+** and conditions see https://www.qt.io/terms-conditions. For further
+** information use the contact form at https://www.qt.io/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 3 as published by the Free Software
+** Foundation and appearing in the file LICENSE.LGPL3 included in the
+** packaging of this file. Please review the following information to
+** ensure the GNU Lesser General Public License version 3 requirements
+** will be met: https://www.gnu.org/licenses/lgpl-3.0.html.
+**
+** GNU General Public License Usage
+** Alternatively, this file may be used under the terms of the GNU
+** General Public License version 2.0 or (at your option) the GNU General
+** Public license version 3 or any later version approved by the KDE Free
+** Qt Foundation. The licenses are as published by the Free Software
+** Foundation and appearing in the file LICENSE.GPL2 and LICENSE.GPL3
+** included in the packaging of this file. Please review the following
+** information to ensure the GNU General Public License requirements will
+** be met: https://www.gnu.org/licenses/gpl-2.0.html and
+** https://www.gnu.org/licenses/gpl-3.0.html.
+**
+** $QT_END_LICENSE$
+**
+****************************************************************************/
+
+#ifndef QSHADERNODESLOADER_P_H
+#define QSHADERNODESLOADER_P_H
+
+//
+//  W A R N I N G
+//  -------------
+//
+// This file is not part of the Qt API.  It exists purely as an
+// implementation detail.  This header file may change from version to
+// version without notice, or even be removed.
+//
+// We mean it.
+//
+
+#include <QtGui/private/qtguiglobal_p.h>
+
+#include <QtGui/private/qshadergraph_p.h>
+
+QT_BEGIN_NAMESPACE
+
+class QIODevice;
+
+class QShaderNodesLoader
+{
+public:
+    enum Status : char {
+        Null,
+        Waiting,
+        Ready,
+        Error
+    };
+
+    Q_GUI_EXPORT QShaderNodesLoader() Q_DECL_NOTHROW;
+
+    Q_GUI_EXPORT Status status() const Q_DECL_NOTHROW;
+    Q_GUI_EXPORT QHash<QString, QShaderNode> nodes() const Q_DECL_NOTHROW;
+
+    Q_GUI_EXPORT QIODevice *device() const Q_DECL_NOTHROW;
+    Q_GUI_EXPORT void setDevice(QIODevice *device) Q_DECL_NOTHROW;
+
+    Q_GUI_EXPORT void load();
+
+private:
+    Status m_status;
+    QIODevice *m_device;
+    QHash<QString, QShaderNode> m_nodes;
+};
+
+Q_DECLARE_TYPEINFO(QShaderNodesLoader, Q_MOVABLE_TYPE);
+
+QT_END_NAMESPACE
+
+Q_DECLARE_METATYPE(QShaderNodesLoader)
+Q_DECLARE_METATYPE(QShaderNodesLoader::Status)
+
+#endif // QSHADERNODESLOADER_P_H
diff --git a/src/gui/util/util.pri b/src/gui/util/util.pri
index bb7a802fd8..c30a46b9af 100644
--- a/src/gui/util/util.pri
+++ b/src/gui/util/util.pri
@@ -12,7 +12,8 @@ HEADERS += \
         util/qshadergraph_p.h \
         util/qshadergraphloader_p.h \
         util/qshadernode_p.h \
-        util/qshadernodeport_p.h
+        util/qshadernodeport_p.h \
+        util/qshadernodesloader_p.h
 
 SOURCES += \
         util/qdesktopservices.cpp \
@@ -25,4 +26,5 @@ SOURCES += \
         util/qshadergraph.cpp \
         util/qshadergraphloader.cpp \
         util/qshadernode.cpp \
-        util/qshadernodeport.cpp
+        util/qshadernodeport.cpp \
+        util/qshadernodesloader.cpp