From 1dd53b56788697971f7aff08232aa91e610c3592 Mon Sep 17 00:00:00 2001
From: Mikko Rasa <tdb@tdb.fi>
Date: Wed, 28 Dec 2022 15:16:21 +0200
Subject: [PATCH] Add an interface for dynamically loaded plugins

---
 source/cli/buildercli.cpp |  1 +
 source/lib/builder.cpp    | 62 +++++++++++++++++++++++++++++++++++++++
 source/lib/builder.h      | 15 ++++++++++
 source/lib/plugin.h       | 20 +++++++++++++
 4 files changed, 98 insertions(+)
 create mode 100644 source/lib/plugin.h

diff --git a/source/cli/buildercli.cpp b/source/cli/buildercli.cpp
index cb0897c..9f8c895 100644
--- a/source/cli/buildercli.cpp
+++ b/source/cli/buildercli.cpp
@@ -87,6 +87,7 @@ BuilderCLI::BuilderCLI(int argc, char **argv):
 		for(const string &p: split(c, ','))
 			logger.enable_channel(p);
 	builder.set_logger(&logger);
+	builder.load_plugins();
 
 	if(!analyze_mode.empty())
 	{
diff --git a/source/lib/builder.cpp b/source/lib/builder.cpp
index 92924eb..72ee524 100644
--- a/source/lib/builder.cpp
+++ b/source/lib/builder.cpp
@@ -22,6 +22,7 @@
 #include "installedfile.h"
 #include "msvc/microsofttools.h"
 #include "package.h"
+#include "plugin.h"
 #include "sharedlibrary.h"
 #include "sourcepackage.h"
 #include "task.h"
@@ -46,6 +47,49 @@ Builder::~Builder()
 		delete current_arch;
 }
 
+void Builder::load_plugins()
+{
+	using CreateFunc = Plugin *(Builder &);
+
+	FS::Path plugins_dir = FS::get_sys_lib_dir();
+	logger->log("files", "Traversing %s", plugins_dir);
+	for(const string &f: list_filtered(plugins_dir, "\\.dlm$"))
+	{
+		LoadedPlugin plugin;
+		plugin.path = plugins_dir/f;
+
+		try
+		{
+			plugin.module = new Module(plugin.path.str());
+		}
+		catch(const exception &exc)
+		{
+			logger->log("plugins", "Failed to load plugin %s: %s", f, exc.what());
+			continue;
+		}
+
+		try
+		{
+			CreateFunc *create_func = reinterpret_cast<CreateFunc *>(plugin.module->get_symbol("create_plugin"));
+			plugin.plugin = create_func(*this);
+			if(plugin.plugin)
+			{
+				logger->log("plugins", "Loaded plugin %s", f);
+				plugins.emplace_back(move(plugin));
+				continue;
+			}
+			else
+				logger->log("plugins", "Plugin %s refused to initialize", f);
+		}
+		catch(const exception &exc)
+		{
+			logger->log("plugins", "Failed to initialize plugin %s: %s", f, exc.what());
+		}
+
+		delete plugin.module;
+	}
+}
+
 void Builder::set_architecture(const string &name)
 {
 	if(current_arch!=&native_arch)
@@ -110,6 +154,8 @@ void Builder::add_default_tools()
 		toolchain.add_toolchain(new MicrosoftTools(*this, *current_arch));
 	toolchain.add_toolchain(new BuiltinTools(*this));
 	toolchain.add_tool(new DataTool(*this));
+	for(const LoadedPlugin &p: plugins)
+		p.plugin->add_tools(toolchain, *current_arch);
 
 	auto i = find_if(toolchain.get_toolchains(), [](const Toolchain *tc){ return (tc->has_tool("CC") || tc->has_tool("CXX")); });
 	if(i!=toolchain.get_toolchains().end())
@@ -310,6 +356,22 @@ int Builder::clean(bool all, bool dry_run)
 }
 
 
+Builder::LoadedPlugin::LoadedPlugin(LoadedPlugin &&other):
+	path(move(other.path)),
+	module(other.module),
+	plugin(other.plugin)
+{
+	other.module = 0;
+	other.plugin = 0;
+}
+
+Builder::LoadedPlugin::~LoadedPlugin()
+{
+	delete plugin;
+	delete module;
+}
+
+
 Builder::Loader::Loader(Builder &b, const Config::InputOptions *o, bool a):
 	DataFile::ObjectLoader<Builder>(b),
 	options(o),
diff --git a/source/lib/builder.h b/source/lib/builder.h
index e06cec3..32d06a0 100644
--- a/source/lib/builder.h
+++ b/source/lib/builder.h
@@ -3,6 +3,7 @@
 
 #include <map>
 #include <string>
+#include <msp/core/module.h>
 #include <msp/datafile/loader.h>
 #include <msp/fs/path.h>
 #include "architecture.h"
@@ -17,6 +18,7 @@
 
 class FileTarget;
 class Package;
+class Plugin;
 class SourcePackage;
 
 /**
@@ -44,6 +46,18 @@ private:
 	};
 
 private:
+	struct LoadedPlugin
+	{
+		Msp::FS::Path path;
+		Msp::Module *module = nullptr;
+		Plugin *plugin = nullptr;
+
+		LoadedPlugin() = default;
+		LoadedPlugin(LoadedPlugin &&);
+		~LoadedPlugin();
+	};
+
+	std::vector<LoadedPlugin> plugins;
 	PackageManager package_manager;
 
 	Architecture native_arch;
@@ -66,6 +80,7 @@ public:
 	Builder();
 	~Builder();
 
+	void load_plugins();
 	PackageManager &get_package_manager() { return package_manager; }
 
 	void set_architecture(const std::string &);
diff --git a/source/lib/plugin.h b/source/lib/plugin.h
new file mode 100644
index 0000000..910e259
--- /dev/null
+++ b/source/lib/plugin.h
@@ -0,0 +1,20 @@
+#ifndef PLUGIN_H_
+#define PLUGIN_H_
+
+class Architecture;
+class Builder;
+class Toolchain;
+
+class Plugin
+{
+protected:
+	Builder &builder;
+
+	Plugin(Builder &b): builder(b) { }
+public:
+	virtual ~Plugin() = default;
+
+	virtual void add_tools(Toolchain &, const Architecture &) const { }
+};
+
+#endif
-- 
2.43.0