Dynamically load FFmpeg and libfdk-aac if available. (#6570)

src/common/dynamic_library/dynamic_library.cpp

@@ -0,0 +1,87 @@
+// Copyright 2023 Citra Emulator Project
+// Licensed under GPLv2 or any later version
+// Refer to the license.txt file included.
+
+#include <fmt/format.h>
+#if defined(_WIN32)
+#include <windows.h>
+#else
+#include <dlfcn.h>
+#endif
+#include "dynamic_library.h"
+
+namespace DynamicLibrary {
+
+DynamicLibrary::DynamicLibrary(std::string_view name, int major, int minor) {
+    auto full_name = GetLibraryName(name, major, minor);
+#if defined(_WIN32)
+    handle = reinterpret_cast<void*>(LoadLibraryA(full_name.c_str()));
+    if (!handle) {
+        DWORD error_message_id = GetLastError();
+        LPSTR message_buffer = nullptr;
+        size_t size =
+            FormatMessageA(FORMAT_MESSAGE_ALLOCATE_BUFFER | FORMAT_MESSAGE_FROM_SYSTEM |
+                               FORMAT_MESSAGE_IGNORE_INSERTS,
+                           nullptr, error_message_id, MAKELANGID(LANG_NEUTRAL, SUBLANG_DEFAULT),
+                           reinterpret_cast<LPSTR>(&message_buffer), 0, nullptr);
+        std::string message(message_buffer, size);
+        load_error = message;
+    }
+#else
+    handle = dlopen(full_name.c_str(), RTLD_LAZY);
+    if (!handle) {
+        load_error = dlerror();
+    }
+#endif // defined(_WIN32)
+}
+
+DynamicLibrary::~DynamicLibrary() {
+    if (handle) {
+#if defined(_WIN32)
+        FreeLibrary(reinterpret_cast<HMODULE>(handle));
+#else
+        dlclose(handle);
+#endif // defined(_WIN32)
+        handle = nullptr;
+    }
+}
+
+void* DynamicLibrary::GetRawSymbol(std::string_view name) {
+#if defined(_WIN32)
+    return reinterpret_cast<void*>(GetProcAddress(reinterpret_cast<HMODULE>(handle), name.data()));
+#else
+    return dlsym(handle, name.data());
+#endif // defined(_WIN32)
+}
+
+std::string DynamicLibrary::GetLibraryName(std::string_view name, int major, int minor) {
+#if defined(_WIN32)
+    if (major >= 0 && minor >= 0) {
+        return fmt::format("{}-{}-{}.dll", name, major, minor);
+    } else if (major >= 0) {
+        return fmt::format("{}-{}.dll", name, major);
+    } else {
+        return fmt::format("{}.dll", name);
+    }
+#elif defined(__APPLE__)
+    auto prefix = name.starts_with("lib") ? "" : "lib";
+    if (major >= 0 && minor >= 0) {
+        return fmt::format("{}{}.{}.{}.dylib", prefix, name, major, minor);
+    } else if (major >= 0) {
+        return fmt::format("{}{}.{}.dylib", prefix, name, major);
+    } else {
+        return fmt::format("{}{}.dylib", prefix, name);
+    }
+#else
+    auto prefix = name.starts_with("lib") ? "" : "lib";
+    if (major >= 0 && minor >= 0) {
+        return fmt::format("{}{}.so.{}.{}", prefix, name, major, minor);
+    } else if (major >= 0) {
+        return fmt::format("{}{}.so.{}", prefix, name, major);
+    } else {
+        return fmt::format("{}{}.so", prefix, name);
+    }
+#endif
+}
+
+} // namespace DynamicLibrary