'--verify-update', shasum support, OpenPGP signatures verification

src/qt/utils.cpp

@@ -37,6 +37,24 @@ bool fileExists(QString path) {
     return check_file.exists() && check_file.isFile();
 }
 
+QByteArray fileGetContents(QString path)
+{
+    QFile file(path);
+    if (!file.open(QFile::ReadOnly))
+    {
+        throw std::runtime_error(QString("failed to open %1").arg(path).toStdString());
+    }
+
+    QByteArray data;
+    data.resize(file.size());
+    if (file.read(data.data(), data.size()) != data.size())
+    {
+        throw std::runtime_error(QString("failed to read %1").arg(path).toStdString());
+    }
+
+    return data;
+}
+
 QByteArray fileOpen(QString path) {
     QFile file(path);
     if(!file.open(QFile::ReadOnly | QFile::Text))