Add load and start plugin scripts

src/openrct2/scripting/Plugin.cpp

@@ -0,0 +1,110 @@
+#pragma region Copyright (c) 2014-2018 OpenRCT2 Developers
+/*****************************************************************************
+ * OpenRCT2, an open source clone of Roller Coaster Tycoon 2.
+ *
+ * OpenRCT2 is the work of many authors, a full list can be found in contributors.md
+ * For more information, visit https://github.com/OpenRCT2/OpenRCT2
+ *
+ * OpenRCT2 is free software: you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation, either version 3 of the License, or
+ * (at your option) any later version.
+ *
+ * A full copy of the GNU General Public License can be found in licence.txt
+ *****************************************************************************/
+#pragma endregion
+
+#include "Plugin.h"
+#include <dukglue/dukglue.h>
+#include <duktape.h>
+#include <algorithm>
+#include <fstream>
+#include <memory>
+
+using namespace OpenRCT2::Scripting;
+
+Plugin::Plugin(duk_context * context, const std::string &path)
+    : _context(context),
+      _path(path)
+{
+}
+
+Plugin::Plugin(const Plugin&& src)
+    : _context(src._context),
+      _path(src._path),
+      _metadata(src._metadata)
+{
+}
+
+void Plugin::Load()
+{
+    std::string projectedVariables = "console,park";
+    std::string code;
+    {
+        std::ifstream fs(_path);
+        if (fs.is_open())
+        {
+            fs.seekg(0, std::ios::end);   
+            code.reserve(fs.tellg());
+            fs.seekg(0, std::ios::beg);
+            code.assign(
+                std::istreambuf_iterator<char>(fs),
+                std::istreambuf_iterator<char>());
+        }
+    }
+    // Wrap the script in a function and pass the global objects as variables
+    // so that if the script modifies them, they are not modified for other scripts.
+    code = "(function(" + projectedVariables + "){" + code + "})(" + projectedVariables + ");";
+    auto flags = DUK_COMPILE_EVAL | DUK_COMPILE_SAFE | DUK_COMPILE_NOSOURCE | DUK_COMPILE_NOFILENAME;
+    auto result = duk_eval_raw(_context, code.c_str(), code.size(), flags);
+    if (result != DUK_ERR_NONE)
+    {
+        auto val = std::string(duk_safe_to_string(_context, -1));
+        duk_pop(_context);
+        throw std::runtime_error("Failed to load plug-in script: " + val);
+    }
+
+    _metadata = GetMetadata(DukValue::take_from_stack(_context));
+}
+
+void Plugin::Start()
+{
+    const auto& mainFunc = _metadata.Main;
+    mainFunc.push();
+    auto result = duk_pcall(_context, 0);
+    if (result != DUK_ERR_NONE)
+    {
+        auto val = std::string(duk_safe_to_string(_context, -1));
+        duk_pop(_context);
+        throw std::runtime_error("[" + _metadata.Name + "] " + val);
+    }
+    duk_pop(_context);
+}
+
+PluginMetadata Plugin::GetMetadata(const DukValue& dukMetadata)
+{
+    PluginMetadata metadata;
+    if (dukMetadata.type() == DukValue::Type::OBJECT)
+    {
+        metadata.Name = dukMetadata["name"].as_string();
+        metadata.Version = dukMetadata["version"].as_string();
+
+        auto dukAuthors = dukMetadata["authors"];
+        dukAuthors.push();
+        if (dukAuthors.is_array())
+        {
+            auto elements = dukAuthors.as_array();
+            std::transform(
+                elements.begin(),
+                elements.end(),
+                std::back_inserter(metadata.Authors),
+                [](const DukValue& v) { return v.as_string(); });
+        }
+        else
+        {
+            metadata.Authors = { dukAuthors.as_string() };
+        }
+        metadata.Main = dukMetadata["main"];
+    }
+    return metadata;
+}