From 37e49590062c96cfa5f32509a88d5371a4dd83f2 Mon Sep 17 00:00:00 2001
From: Mikko Rasa <tdb@tdb.fi>
Date: Sat, 29 Oct 2016 19:43:42 +0300
Subject: [PATCH] Add a class for loading and accessing modules at runtime

---
 source/core/module.h                  | 24 ++++++++++++++++
 source/core/module_private.h          | 16 +++++++++++
 source/core/unix/module.cpp           | 40 +++++++++++++++++++++++++++
 source/core/unix/module_platform.h    | 10 +++++++
 source/core/windows/module.cpp        | 34 +++++++++++++++++++++++
 source/core/windows/module_platform.h | 12 ++++++++
 6 files changed, 136 insertions(+)
 create mode 100644 source/core/module.h
 create mode 100644 source/core/module_private.h
 create mode 100644 source/core/unix/module.cpp
 create mode 100644 source/core/unix/module_platform.h
 create mode 100644 source/core/windows/module.cpp
 create mode 100644 source/core/windows/module_platform.h

diff --git a/source/core/module.h b/source/core/module.h
new file mode 100644
index 0000000..1d008ba
--- /dev/null
+++ b/source/core/module.h
@@ -0,0 +1,24 @@
+#ifndef MSP_CORE_MODULE_H_
+#define MSP_CORE_MODULE_H_
+
+#include <string>
+
+namespace Msp {
+
+class Module
+{
+private:
+	struct Private;
+
+	Private *priv;
+
+public:
+	Module(const std::string &);
+	~Module();
+
+	void *get_symbol(const std::string &) const;
+};
+
+} // namespace Msp
+
+#endif
diff --git a/source/core/module_private.h b/source/core/module_private.h
new file mode 100644
index 0000000..52d8659
--- /dev/null
+++ b/source/core/module_private.h
@@ -0,0 +1,16 @@
+#ifndef MSP_CORE_MODULE_PRIVATE_H_
+#define MSP_CORE_MODULE_PRIVATE_H_
+
+#include "module.h"
+#include "module_platform.h"
+
+namespace Msp {
+
+struct Module::Private
+{
+	ModuleHandle handle;
+};
+
+} // namespace Msp
+
+#endif
diff --git a/source/core/unix/module.cpp b/source/core/unix/module.cpp
new file mode 100644
index 0000000..04b9531
--- /dev/null
+++ b/source/core/unix/module.cpp
@@ -0,0 +1,40 @@
+#include <dlfcn.h>
+#include "module.h"
+#include "module_private.h"
+#include "systemerror.h"
+
+using namespace std;
+
+namespace Msp {
+
+Module::Module(const string &name)
+{
+	ModuleHandle handle = dlopen(name.c_str(), RTLD_NOW);
+	if(!handle)
+		throw system_error("dlopen", dlerror());
+
+	priv = new Private;
+	priv->handle = handle;
+}
+
+Module::~Module()
+{
+	dlclose(priv->handle);
+	delete priv;
+}
+
+void *Module::get_symbol(const string &name) const
+{
+	dlerror();
+	void *result = dlsym(priv->handle, name.c_str());
+	if(!result)
+	{
+		const char *err = dlerror();
+		if(err)
+			throw system_error("dlsym", err);
+	}
+
+	return result;
+}
+
+} // namespace Msp
diff --git a/source/core/unix/module_platform.h b/source/core/unix/module_platform.h
new file mode 100644
index 0000000..d40f9e7
--- /dev/null
+++ b/source/core/unix/module_platform.h
@@ -0,0 +1,10 @@
+#ifndef MSP_CORE_MODULE_PLATFORM_H_
+#define MSP_CORE_MODULE_PLATFORM_H_
+
+namespace Msp {
+
+typedef void *ModuleHandle;
+
+} // namespace Msp
+
+#endif
diff --git a/source/core/windows/module.cpp b/source/core/windows/module.cpp
new file mode 100644
index 0000000..a0301c1
--- /dev/null
+++ b/source/core/windows/module.cpp
@@ -0,0 +1,34 @@
+#include "module.h"
+#include "module_private.h"
+#include "systemerror.h"
+
+using namespace std;
+
+namespace Msp {
+
+Module::Module(const string &name)
+{
+	ModuleHandle handle = LoadLibrary(name.c_str());
+	if(!handle)
+		throw system_error("LoadLibrary");
+
+	priv = new Private;
+	priv->handle = handle;
+}
+
+Module::~Module()
+{
+	FreeLibrary(priv->handle);
+	delete priv;
+}
+
+void *Module::get_symbol(const string &name) const
+{
+	FARPROC result = GetProcAddress(priv->handle, name.c_str());
+	if(!result)
+		throw system_error("GetProcAddress");
+
+	return reinterpret_cast<void *>(result);
+}
+
+} // namespace Msp
diff --git a/source/core/windows/module_platform.h b/source/core/windows/module_platform.h
new file mode 100644
index 0000000..81dfd0f
--- /dev/null
+++ b/source/core/windows/module_platform.h
@@ -0,0 +1,12 @@
+#ifndef MSP_CORE_MODULE_PLATFORM_H_
+#define MSP_CORE_MODULE_PLATFORM_H_
+
+#include <windows.h>
+
+namespace Msp {
+
+typedef HMODULE ModuleHandle;
+
+} // namespace Msp;
+
+#endif
-- 
2.43.0