poco/Foundation/include/Poco/SharedLibrary.h

//
// SharedLibrary.h
//
// Library: Foundation
// Package: SharedLibrary
// Module:  SharedLibrary
//
// Definition of the SharedLibrary class.
//
// Copyright (c) 2004-2006, Applied Informatics Software Engineering GmbH.
// and Contributors.
//
// SPDX-License-Identifier:	BSL-1.0
//


#ifndef Foundation_SharedLibrary_INCLUDED
#define Foundation_SharedLibrary_INCLUDED


#include "Poco/Foundation.h"
#include <vector>
#include <string>


#if defined(hpux) || defined(_hpux)
#include "Poco/SharedLibrary_HPUX.h"
#elif defined(POCO_VXWORKS)
#include "Poco/SharedLibrary_VX.h"
#elif defined(POCO_OS_FAMILY_UNIX)
#include "Poco/SharedLibrary_UNIX.h"
#elif defined(POCO_OS_FAMILY_WINDOWS)
#include "Poco/SharedLibrary_WIN32U.h"
#endif


namespace Poco {


class Foundation_API SharedLibrary: private SharedLibraryImpl
	/// The SharedLibrary class dynamically
	/// loads shared libraries at run-time.
{
public:
	enum Flags
	{
		SHLIB_GLOBAL = 1,
			/// On platforms that use dlopen(), use RTLD_GLOBAL. This is the default
			/// if no flags are given.
			///
			/// This flag is ignored on platforms that do not use dlopen().

		SHLIB_LOCAL  = 2
			/// On platforms that use dlopen(), use RTLD_LOCAL instead of RTLD_GLOBAL.
			///
			/// Note that if this flag is specified, RTTI (including dynamic_cast and throw) will
			/// not work for types defined in the shared library with GCC and possibly other
			/// compilers as well. See http://gcc.gnu.org/faq.html#dso for more information.
			///
			/// This flag is ignored on platforms that do not use dlopen().
	};

	SharedLibrary();
		/// Creates a SharedLibrary object.

	SharedLibrary(const std::string& path);
		/// Creates a SharedLibrary object and loads a library
		/// from the given path.

	SharedLibrary(const std::string& path, int flags);
		/// Creates a SharedLibrary object and loads a library
		/// from the given path, using the given flags.
		/// See the Flags enumeration for valid values.

	virtual ~SharedLibrary();
		/// Destroys the SharedLibrary. The actual library
		/// remains loaded.

	void load(const std::string& path);
		/// Loads a shared library from the given path.
		/// Throws a LibraryAlreadyLoadedException if
		/// a library has already been loaded.
		/// Throws a LibraryLoadException if the library
		/// cannot be loaded.

	void load(const std::string& path, int flags);
		/// Loads a shared library from the given path,
		/// using the given flags. See the Flags enumeration
		/// for valid values.
		/// Throws a LibraryAlreadyLoadedException if
		/// a library has already been loaded.
		/// Throws a LibraryLoadException if the library
		/// cannot be loaded.

	void unload();
		/// Unloads a shared library.

	bool isLoaded() const;
		/// Returns true iff a library has been loaded.

	bool hasSymbol(const std::string& name);
		/// Returns true iff the loaded library contains
		/// a symbol with the given name.

	void* getSymbol(const std::string& name);
		/// Returns the address of the symbol with
		/// the given name. For functions, this
		/// is the entry point of the function.
		/// Throws a NotFoundException if the symbol
		/// does not exist.

	const std::string& getPath() const;
		/// Returns the path of the library, as
		/// specified in a call to load() or the
		/// constructor.

	static std::string suffix();
		/// Returns the platform-specific filename suffix
		/// for shared libraries (including the period).
		/// In debug mode, the suffix also includes a
		/// "d" to specify the debug version of a library
		/// (e.g., "d.so", "d.dll") unless the library has
		/// been compiled with -DPOCO_NO_SHARED_LIBRARY_DEBUG_SUFFIX.

	static bool setSearchPath(const std::string& path);
		/// Adds the given path to the list of paths shared libraries
		/// are searched in.
		///
		/// Returns true if the path was set, otherwise false.
		///
		/// Currently only supported on Windows, where it calls
		/// SetDllDirectory(). On all other platforms, does not
		/// do anything and returns false.

	static std::vector<std::string> findMissingDependencies(const std::string& path);
		/// Parses the shared library at the given path and returns
		/// a list of dependent libraries that cannot be found.
		/// If the library itself whose dependencies are checked is not found,
		/// it returns the library itself.
		///
		/// Useful for diagnosing why a library fails to load.
		/// On Windows, parses the PE import table. On Linux, parses the
		/// ELF dynamic section. On macOS, parses the Mach-O load commands.
		///
		/// Returns an empty vector if the file cannot be parsed or
		/// on unsupported platforms.

private:
	SharedLibrary(const SharedLibrary&);
	SharedLibrary& operator = (const SharedLibrary&);
};


} // namespace Poco


#endif // Foundation_SharedLibrary_INCLUDED