[Performous-commit] Lasse Karkkainen : Add dll symbol loading to libplugin++

[Lasse Kärkkäi. <tr...@us...>]

Module: performous
Branch: master
Commit: 358bf49e58d6fafdd41db067663c9668535d3fb4

Author: Lasse Karkkainen <tro...@tr...>
Date:   Wed Nov 18 16:02:06 2009 +0200

Add dll symbol loading to libplugin++

---

 libs/plugin++/include/plugin++/dll.hpp |   25 +++++++++++++++++++++++--
 libs/plugin++/src/dll.cc               |   12 ++++++++++--
 2 files changed, 33 insertions(+), 4 deletions(-)

diff --git a/libs/plugin++/include/plugin++/dll.hpp b/libs/plugin++/include/plugin++/dll.hpp
index ed4a7b6..39aa091 100644
--- a/libs/plugin++/include/plugin++/dll.hpp
+++ b/libs/plugin++/include/plugin++/dll.hpp
@@ -1,16 +1,37 @@
+#pragma once
 #ifndef DLL_HPP_INCLUDED
 #define DLL_HPP_INCLUDED
 
 #include "dllhelper.hpp"
+#include <stdexcept>
 #include <string>
 
 namespace plugin {
-    /** @short RAII wrapper to load and unload dynamic library **/
+
+	/// \brief Exception class for signaling runtime errors from class dll
+	class dll_error: public std::runtime_error {
+	public:
+		dll_error(std::string const& msg): runtime_error(msg) {}
+	};
+
+    /// \brief Dynamic library loader
     class DLL_PUBLIC dll {
         void* lib;
-      public:
+    public:
+    	/// Open a dynamic library
+    	/// \throws dll_error if the library cannot be loaded
         dll(std::string const& filename);
         ~dll();
+        /// Get a symbol from DLL (symptr can be a data or a function pointer)
+        /// \throws dll_error if no symbol is found
+        template <typename SymPtr> void sym(std::string const& name, SymPtr& symptr) {
+        	union { void* ptr; SymPtr symptr; } conv;  // Data/function conversion without warnings
+        	conv.ptr = sym(name.c_str());
+        	if (!conv.ptr) throw dll_error("Symbol " + name + " not found");
+        	symptr = conv.symptr;
+        }
+        /// Get a symbol from DLL (low level C style version)
+        void* sym(char const* name);
     };
 }
 
diff --git a/libs/plugin++/src/dll.cc b/libs/plugin++/src/dll.cc
index f684654..73662e6 100644
--- a/libs/plugin++/src/dll.cc
+++ b/libs/plugin++/src/dll.cc
@@ -11,19 +11,27 @@ using namespace plugin;
 #include <windows.h>
 
 dll::dll(std::string const& filename): lib(LoadLibrary(filename.c_str())) {
-	if (!lib) throw std::runtime_error("Unable to open " + filename);
+	if (!lib) throw dll_error("Unable to open " + filename);
 }
 
 dll::~dll() { FreeLibrary(static_cast<HINSTANCE>(lib)); }
 
+void* dll::sym(char const* sym) {
+	return GetProcAddress(static_cast<HINSTANCE>(lib), sym);
+}
+
 #else
 
 #include <dlfcn.h>
 
 dll::dll(std::string const& filename): lib(dlopen(filename.c_str(), RTLD_LAZY | RTLD_GLOBAL)) {
-	if (!lib) throw std::runtime_error(dlerror());
+	if (!lib) throw dll_error(dlerror());
 }
 
 dll::~dll() { dlclose(lib); }
 
+void* dll::sym(char const* sym) {
+	return dlsym(lib, sym);
+}
+
 #endif