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Common: Add DynamicLibrary helper class

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stenzek committed Mar 9, 2019
1 parent e9cfcf4 commit a4f7c04470152c0964bbef78bce611867c4f0ef6
@@ -11,6 +11,7 @@ add_library(common
Crypto/ec.cpp
Debug/MemoryPatches.cpp
Debug/Watches.cpp
DynamicLibrary.cpp
ENetUtil.cpp
File.cpp
FileSearch.cpp
@@ -63,6 +63,7 @@
<ClInclude Include="DebugInterface.h" />
<ClInclude Include="Debug\MemoryPatches.h" />
<ClInclude Include="Debug\Watches.h" />
<ClInclude Include="DynamicLibrary.h" />
<ClInclude Include="ENetUtil.h" />
<ClInclude Include="Event.h" />
<ClInclude Include="File.h" />
@@ -184,6 +185,7 @@
<ClCompile Include="Config\Layer.cpp" />
<ClCompile Include="Debug\MemoryPatches.cpp" />
<ClCompile Include="Debug\Watches.cpp" />
<ClCompile Include="DynamicLibrary.cpp" />
<ClCompile Include="ENetUtil.cpp" />
<ClCompile Include="File.cpp" />
<ClCompile Include="FileSearch.cpp" />
@@ -258,4 +260,4 @@
<Import Project="$(VCTargetsPath)\Microsoft.Cpp.targets" />
<ImportGroup Label="ExtensionTargets">
</ImportGroup>
</Project>
</Project>
@@ -276,6 +276,8 @@
<ClInclude Include="GL\GLContext.h">
<Filter>GL\GLInterface</Filter>
</ClInclude>
<ClInclude Include="VariantUtil.h" />
<ClInclude Include="DynamicLibrary.h" />
</ItemGroup>
<ItemGroup>
<ClCompile Include="CDUtils.cpp" />
@@ -357,11 +359,12 @@
<ClCompile Include="GL\GLContext.cpp">
<Filter>GL\GLInterface</Filter>
</ClCompile>
<ClCompile Include="DynamicLibrary.cpp" />
</ItemGroup>
<ItemGroup>
<Text Include="CMakeLists.txt" />
</ItemGroup>
<ItemGroup>
<Natvis Include="BitField.natvis" />
</ItemGroup>
</Project>
</Project>
@@ -0,0 +1,100 @@
// Copyright 2019 Dolphin Emulator Project
// Licensed under GPLv2+
// Refer to the license.txt file included.

#include "Common/DynamicLibrary.h"
#include <cstring>
#include "Common/Assert.h"
#include "Common/StringUtil.h"

#ifdef _WIN32
#include <Windows.h>
#else
#include <dlfcn.h>
#endif

namespace Common
{
DynamicLibrary::DynamicLibrary() = default;

DynamicLibrary::DynamicLibrary(const char* filename)
{
Open(filename);
}

DynamicLibrary::~DynamicLibrary()
{
Close();
}

std::string DynamicLibrary::GetUnprefixedFilename(const char* filename)
{
#if defined(_WIN32)
return std::string(filename) + ".dll";
#elif defined(__APPLE__)
return std::string(filename) + ".dylib";
#else
return std::string(filename) + ".so";
#endif
}

std::string DynamicLibrary::GetVersionedFilename(const char* libname, int major, int minor)
{
#if defined(_WIN32)
if (major >= 0 && minor >= 0)
return StringFromFormat("%s-%d-%d.dll", libname, major, minor);
else if (major >= 0)
return StringFromFormat("%s-%d.dll", libname, major);
else
return StringFromFormat("%s.dll", libname);
#elif defined(__APPLE__)
const char* prefix = std::strncmp(libname, "lib", 3) ? "lib" : "";
if (major >= 0 && minor >= 0)
return StringFromFormat("%s%s.%d.%d.dylib", prefix, libname, major, minor);
else if (major >= 0)
return StringFromFormat("%s%s.%d.dylib", prefix, libname, major);
else
return StringFromFormat("%s%s.dylib", prefix, libname);
#else
const char* prefix = std::strncmp(libname, "lib", 3) ? "lib" : "";
if (major >= 0 && minor >= 0)
return StringFromFormat("%s%s.so.%d.%d", prefix, libname, major, minor);
else if (major >= 0)
return StringFromFormat("%s%s.so.%d", prefix, libname, major);
else
return StringFromFormat("%s%s.so", prefix, libname);
#endif
}

bool DynamicLibrary::Open(const char* filename)
{
#ifdef _WIN32
m_handle = reinterpret_cast<void*>(LoadLibraryA(filename));
#else
m_handle = dlopen(filename, RTLD_NOW);
#endif
return m_handle != nullptr;
}

void DynamicLibrary::Close()
{
if (!IsOpen())
return;

#ifdef _WIN32
FreeLibrary(reinterpret_cast<HMODULE>(m_handle));
#else
dlclose(m_handle);
#endif
m_handle = nullptr;
}

void* DynamicLibrary::GetSymbolAddress(const char* name) const
{
#ifdef _WIN32
return reinterpret_cast<void*>(GetProcAddress(reinterpret_cast<HMODULE>(m_handle), name));
#else
return reinterpret_cast<void*>(dlsym(m_handle, name));
#endif
}
} // namespace Common
@@ -0,0 +1,67 @@
// Copyright 2019 Dolphin Emulator Project
// Licensed under GPLv2+
// Refer to the license.txt file included.

#pragma once
#include <atomic>
#include <string>

namespace Common
{
/**
* Provides a platform-independent interface for loading a dynamic library and retrieving symbols.
* The interface maintains an internal reference count to allow one handle to be shared between
* multiple users.
*/
class DynamicLibrary final
{
public:
// Default constructor, does not load a library.
DynamicLibrary();

// Automatically loads the specified library. Call IsOpen() to check validity before use.
DynamicLibrary(const char* filename);

// Closes the library.
~DynamicLibrary();

// Returns the specified library name with the platform-specific suffix added.
static std::string GetUnprefixedFilename(const char* filename);

// Returns the specified library name in platform-specific format.
// Major/minor versions will not be included if set to -1.
// If libname already contains the "lib" prefix, it will not be added again.
// Windows: LIBNAME-MAJOR-MINOR.dll
// Linux: libLIBNAME.so.MAJOR.MINOR
// Mac: libLIBNAME.MAJOR.MINOR.dylib
static std::string GetVersionedFilename(const char* libname, int major = -1, int minor = -1);

// Returns true if a module is loaded, otherwise false.
bool IsOpen() const { return m_handle != nullptr; }

// Loads (or replaces) the handle with the specified library file name.
// Returns true if the library was loaded and can be used.
bool Open(const char* filename);

// Unloads the library, any function pointers from this library are no longer valid.
void Close();

// Returns the address of the specified symbol (function or variable) as an untyped pointer.
// If the specified symbol does not exist in this library, nullptr is returned.
void* GetSymbolAddress(const char* name) const;

// Obtains the address of the specified symbol, automatically casting to the correct type.
// Returns true if the symbol was found and assigned, otherwise false.
template <typename T>
bool GetSymbol(const char* name, T* ptr) const
{
*ptr = reinterpret_cast<T>(GetSymbolAddress(name));
return *ptr != nullptr;
}

private:
// Platform-dependent data type representing a dynamic library handle.
void* m_handle = nullptr;
};

} // namespace Common

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