73 lines
2.2 KiB
C++
73 lines
2.2 KiB
C++
/*
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* Copyright (C) 2022 The Android Open Source Project
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*
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* Licensed under the Apache License, Version 2.0 (the "License");
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* you may not use this file except in compliance with the License.
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* You may obtain a copy of the License at
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*
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* http://www.apache.org/licenses/LICENSE-2.0
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*
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* Unless required by applicable law or agreed to in writing, software
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* distributed under the License is distributed on an "AS IS" BASIS,
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* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
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* See the License for the specific language governing permissions and
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* limitations under the License.
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*/
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#define LOG_TAG "Library"
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#include <utils/Log.h>
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#include <mediautils/Library.h>
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namespace {
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std::string dlerrorIfPresent() {
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const char *dlerr = dlerror();
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if (dlerr == nullptr) return "dlerror: none";
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return std::string("dlerror: '").append(dlerr).append("'");
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}
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}
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namespace android::mediautils {
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std::shared_ptr<void> loadLibrary(const char *libraryName, int flags) {
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std::shared_ptr<void> library{
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dlopen(libraryName, flags),
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[](void *lib) {
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if (lib != nullptr) {
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const int ret = dlclose(lib);
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ALOGW_IF(ret !=0, "%s: dlclose(%p) == %d, %s",
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__func__, lib, ret, dlerrorIfPresent().c_str());
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}
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}
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};
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if (!library) {
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ALOGW("%s: cannot load libraryName %s, %s",
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__func__, libraryName, dlerrorIfPresent().c_str());
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return {};
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}
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return library;
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}
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std::shared_ptr<void> getUntypedObjectFromLibrary(
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const char *objectName, const std::shared_ptr<void>& library) {
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if (!library) {
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ALOGW("%s: null library, cannot load objectName %s", __func__, objectName);
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return {};
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}
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void *ptr = dlsym(library.get(), objectName);
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if (ptr == nullptr) {
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ALOGW("%s: cannot load objectName %s, %s",
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__func__, objectName, dlerrorIfPresent().c_str());
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return {};
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}
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// Note: we use the "aliasing" constructor of the std:shared_ptr.
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//
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// https://en.cppreference.com/w/cpp/memory/shared_ptr/shared_ptr
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//
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return { library, ptr }; // returns shared_ptr to ptr, but ref counted on library.
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}
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} // namespace android::mediautils
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