From 9b88f3ce47d090df167263ce2b4b6b430694da72 Mon Sep 17 00:00:00 2001
From: "kali kaneko (leap communications)" <kali@leap.se>
Date: Thu, 4 Jun 2020 11:39:41 +0200
Subject: [feat] add qt gui

Signed-off-by: kali kaneko (leap communications) <kali@leap.se>
---
 gui/main.cpp | 111 +++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 111 insertions(+)
 create mode 100644 gui/main.cpp

(limited to 'gui/main.cpp')

diff --git a/gui/main.cpp b/gui/main.cpp
new file mode 100644
index 0000000..f2545d3
--- /dev/null
+++ b/gui/main.cpp
@@ -0,0 +1,111 @@
+#include <QGuiApplication>
+#include <QQmlApplicationEngine>
+#include <QQuickWindow>
+#include <QTimer>
+#include <QtQml>
+#include <string>
+
+#include "handlers.h"
+#include "qjsonmodel.h"
+#include "lib/libgoshim.h"
+
+/* Hi! I'm Troy McClure and I'll be your guide today. You probably remember me
+   from blockbusters like "here be dragons" and "darling, I wrote a little
+   contraption". */
+
+/* Our glorious global object state. In here we store a serialized snapshot of
+   the context from the application "backend", living in the linked Go-land
+   lib. */
+
+static char *json;
+
+/* We are interested in observing changes to this global json variable.
+   The jsonWatchdog bridges the gap from pure c callbacks to the rest of the c++
+   logic. QJsonWatch comes from QObject so it can emit signals. */
+
+QJsonWatch *qw;
+
+struct jsonWatchdog {
+    jsonWatchdog() { qw = new QJsonWatch; }
+    void changed() { emit qw->jsonChanged(QString(json)); }
+};
+
+/* we need C wrappers around every C++ object, so that we can invoke their methods
+   from the function pointers passed as callbacks to CGO. */
+extern "C" {
+static void *newWatchdog(void) { return (void *)(new jsonWatchdog); }
+static void jsonChanged(void *ptr) {
+    if (ptr != NULL) {
+        jsonWatchdog *klsPtr = static_cast<jsonWatchdog *>(ptr);
+        klsPtr->changed();
+    }
+}
+}
+
+void *wd = newWatchdog();
+
+/* onStatusChanged is the C function that we register as a callback with CGO,
+   to be called from the Go side. It pulls a string serialization of the
+   context object, than we then pass along to Qt objects and to Qml. */
+void onStatusChanged() {
+    char *ctx = RefreshContext();
+    json = ctx;
+    /* the method wrapped emits a qt signal */
+    jsonChanged(wd);
+    free(ctx);
+}
+
+std::string getEnv(std::string const& key)
+{
+    char const* val = getenv(key.c_str());
+    return val == NULL ? std::string() : std::string(val);
+}
+
+int main(int argc, char **argv) {
+
+    bool debugQml = getEnv("DEBUG_QML_DATA") == "yes";
+
+    QGuiApplication::setAttribute(Qt::AA_EnableHighDpiScaling);
+    QGuiApplication app(argc, argv);
+    app.setQuitOnLastWindowClosed(false);
+    QQmlApplicationEngine engine;
+    QQmlContext *ctx = engine.rootContext();
+
+    QJsonModel *model = new QJsonModel;
+    std::string json = R"({"appName": "unknown", "provider": "unknown"})";
+    model->loadJson(QByteArray::fromStdString(json));
+
+    /* the backend handler has slots for calling back to Go when triggered by
+       signals in Qml. */
+    Backend backend;
+    ctx->setContextProperty("backend", &backend);
+
+    /* set the json model, load the qml */
+    ctx->setContextProperty("jsonModel", model);
+    ctx->setContextProperty("debugQml", debugQml);
+
+    engine.load(QUrl(QStringLiteral("qrc:/qml/main.qml")));
+
+    /* connect the jsonChanged signal explicitely.
+        In the lambda, we reload the json in the model every time we receive an
+        update from Go */
+    QObject::connect(qw, &QJsonWatch::jsonChanged, [ctx, model](QString js) {
+        model->loadJson(js.toUtf8());
+    });
+
+    /* connect quitDone signal, exit app */
+    QObject::connect(&backend, &Backend::quitDone, []() {
+            QGuiApplication::quit();
+    });
+
+    /* register statusChanged callback with CGO */
+    const char *stCh = "OnStatusChanged";
+    GoString statusChangedEvt = {stCh, (long int)strlen(stCh)};
+    SubscribeToEvent(statusChangedEvt, (void *)onStatusChanged);
+
+    /* let the Go side initialize its internal state */
+    InitializeBitmaskContext();
+
+    /* kick off your shoes, put your feet up */
+    return app.exec();
+}
-- 
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