gnss/1.0/default/ThreadCreationWrapper.h

/*
 * Copyright (C) 2016 The Android Open Source Project
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 *      http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */

#ifndef ANDROID_HARDWARE_GNSS_THREADCREATIONWRAPPER_H
#define ANDROID_HARDWARE_GNSS_THREADCREATIONWRAPPER_H

#include <log/log.h>
#include <pthread.h>
#include <vector>

typedef void (*threadEntryFunc)(void* ret);

/*
 * This class facilitates createThreadCb methods in various GNSS interfaces to wrap
 * pthread_create() from libc since its function signature differs from what is required by the
 * conventional GNSS HAL. The arguments passed to pthread_create() need to be on heap and not on
 * the stack of createThreadCb.
 */
struct ThreadFuncArgs {
    ThreadFuncArgs(void (*start)(void*), void* arg) : fptr(start), args(arg) {}

    /* pointer to the function of type void()(void*) that needs to be wrapped */
    threadEntryFunc fptr;
    /* argument for fptr to be called with */
    void* args;
};

/*
 * This method is simply a wrapper. It is required since pthread_create() requires an entry
 * function pointer of type void*()(void*) and the GNSS hal requires as input a function pointer of
 * type void()(void*).
 */
void* threadFunc(void* arg);

/*
 * This method is called by createThreadCb with a pointer to the vector that
 * holds the pointers to the thread arguments. The arg and start parameters are
 * first used to create a ThreadFuncArgs object which is then saved in the
 * listArgs parameters. The created ThreadFuncArgs object is then used to invoke
 * threadFunc() method which in-turn invokes pthread_create.
 */
pthread_t createPthread(const char* name, void (*start)(void*), void* arg,
                        std::vector<std::unique_ptr<ThreadFuncArgs>> * listArgs);

#endif