CarPlay for Android: R12d 插件源码移植到Linux

1. R12d 插件源码结构与R11之间的差异

    R12d源码结构与R11有差异较大，去掉了IPC方式，增加了AccessorySDK、Transport目录， 并且AccessorySDK目录下也有个makefile。之前有的目录内容也完全不一样了，支持无线CarPlay方式，要求使用mDNSResponder-567版本的Bonjour。    环境配置及R11源码编译的方式请参考博主以前的博文：

CarPlay for Android： Bonjour 及 插件源码移植问题分析 ：http://blog.csdn.net/romantic_energy/article/details/46680355

2. R12d 插件源码移植到Linux
    把插件源码拷贝到Linux环境下，插件根目录下有源码目录和Examples，把源码目录修改为CarPlay_Plugin，
把Bonjour源码拷贝到插件目录下，去掉版本号，改名为mDNSResponder。修改完成后，插件根目录下有3个目录：
CarPlay_Plugin、Examples、mDNSResponder.
首先编译mDNSResponder：shell进入mDNSResponder\mDNSPosix目录下，执行make，环境搭建好了的话，此步骤没有问题。
然后编译插件源码：shell进入CarPlay_Plugin\PlatformPOSIX目录下，执行make，报以下错误：
cc1: warnings being treated as errors
In file included from ***/CarPlay_Plugin/PlatformPOSIX/../build/Release-unknown/CoreUtils/CFCompat.h:8,
                 from ***/CarPlay_Plugin/PlatformPOSIX/../Sources/AirPlaySettings.h:9,
                 from ***/CarPlay_Plugin/PlatformPOSIX/../Sources/AirPlaySettings.c:5:
***/CarPlay_Plugin/PlatformPOSIX/../build/Release-unknown/CoreUtils/CommonServices.h:1638: error: "__SIZEOF_INT128__" is not defined
make: *** [***/CarPlay_Plugin/PlatformPOSIX/../build/Release-unknown/obj/AirPlaySettings.so.o] Error 1

cc1: warnings being treated as errors意为将编译警告视为错误，因为无法去掉所有警告，将makefile中的
COMMON_WARNINGS            += -Werror
行注释掉， 即：
#COMMON_WARNINGS            += -Werror

修改后执行make，报以下错误：
Linking (unknown-Release) \033[0;35mlibAirPlay.so\033[0m
/usr/bin/ld: ***/CarPlay_Plugin/PlatformPOSIX/../build/Release-unknown/obj/AirPlayNTPClient.o: relocation R_X86_64_32 against `gLogCategory_AirPlayNTPClientCore' can not be used when making a shared object; recompile with -fPIC
***/CarPlay_Plugin/PlatformPOSIX/../build/Release-unknown/obj/AirPlayNTPClient.o: could not read symbols: Bad value
collect2: ld returned 1 exit status
make: *** [***/CarPlay_Plugin/PlatformPOSIX/../build/Release-unknown/libAirPlay.so] Error 1
按编译器提升：recompile with -fPIC
即增加一行：
COMMONFLAGS        += -fPIC
后make clean, 然后继续make编译，会得到以下错误：
Compiling (unknown-Release-shared) \033[0;35mAudioUtilsStub.c\033[0m
In file included from ***/CarPlay_Plugin/PlatformPOSIX/../build/Release-unknown/CoreUtils/CFUtils.h:10,
                 from ***/CarPlay_Plugin/PlatformPOSIX/../build/Release-unknown/CoreUtils/AudioUtils.h:12,
                 from ***/CarPlay_Plugin/PlatformPOSIX/../Support/AudioUtilsStub.c:5:
***/CarPlay_Plugin/PlatformPOSIX/../build/Release-unknown/CoreUtils/CommonServices.h:1638: warning: "__SIZEOF_INT128__" is not defined
***/CarPlay_Plugin/PlatformPOSIX/../Support/AudioUtilsStub.c:673: error: expected identifier or '(' before '{' token
make: *** [***/CarPlay_Plugin/PlatformPOSIX/../build/Release-unknown/obj/AudioUtilsStub.so.o] Error 1

Compiling (unknown-Release-shared)意为为未知系统编译，说明我们make的时候带的参数不够，查看makefile后发现，应该使用make os=linux.
查看/CarPlay_Plugin/PlatformPOSIX/../Support/AudioUtilsStub.c 673行，发现此行多了一个";"号，即：
APSAudioSessionAudioFormat    APSAudioSessionGetSupportedFormats( AudioStreamType inStreamType, CFStringRef inAudioType );
{
    ...
}
去掉";"号即可；

make clean 后执行 make os=linux, 提升以下错误：
Making (linux-Release) \033[0;35mlibCoreUtils.so\033[0m
make[1]: Entering directory `***/CarPlay_Plugin/AccessorySDK/PlatformPOSIX'
Compiling (linux--Release-shared) \033[0;35mAsyncConnection.c\033[0m
***/CarPlay_Plugin/AccessorySDK/PlatformPOSIX/../Support/AsyncConnection.c:36: fatal error: dns_sd.h: No such file or directory
compilation terminated.
make[1]: *** [***/CarPlay_Plugin/PlatformPOSIX/../build/Release-linux/obj/AsyncConnection.so.o] Error 1
make[1]: Leaving directory `***/CarPlay_Plugin/AccessorySDK/PlatformPOSIX'
make: *** [***/CarPlay_Plugin/PlatformPOSIX/../build/Release-linux/libCoreUtils.so] Error 2

阅读makefile后发现没有指定Bonjour的路径，于是在makefile中增加include 目录：
INCLUDES                += -I$(SRCROOT)/../mDNSResponder/mDNSShared
重新make后还是报相同的错误，久寻未果，后发现报错的makefile是/CarPlay_Plugin/AccessorySDK/PlatformPOSIX中的makefile，
应该是此makefile中的目录不对，遂及把/CarPlay_Plugin/AccessorySDK/PlatformPOSIX中的makefile中的
MDNSROOT        = $(SRCROOT)/../mDNSResponder
改为：
MDNSROOT        = $(SRCROOT)/../../mDNSResponder
后此处编译通过。但是还是有其他错误：
cc1: warnings being treated as errors
***/CarPlay_Plugin/AccessorySDK/PlatformPOSIX/../Support/CFLite.c: In function 'CFLRetain':
***/CarPlay_Plugin/AccessorySDK/PlatformPOSIX/../Support/CFLite.c:400: error: implicit declaration of function 'atomic_add_and_fetch_32'
***/CarPlay_Plugin/AccessorySDK/PlatformPOSIX/../Support/CFLite.c: In function 'CFLRuntimeRegisterClass':
***/CarPlay_Plugin/AccessorySDK/PlatformPOSIX/../Support/CFLite.c:3359: error: implicit declaration of function 'atomic_bool_compare_and_swap_32'
***/CarPlay_Plugin/AccessorySDK/PlatformPOSIX/../Support/CFLite.c:3370: error: implicit declaration of function 'atomic_read_write_barrier'
make[1]: *** [***/CarPlay_Plugin/PlatformPOSIX/../build/Release-linux/obj/CFLite.so.o] Error 1
make[1]: Leaving directory `***/CarPlay_Plugin/AccessorySDK/PlatformPOSIX'
make: *** [***/CarPlay_Plugin/PlatformPOSIX/../build/Release-linux/libCoreUtils.so] Error 2
在/CarPlay_Plugin/AccessorySDK/PlatformPOSIX中的makefile中增加
COMMONFLAGS            += -DAtomicUtils_HAS_SYNC_BUILTINS=1
COMMONFLAGS        += -fPIC
后解决。

继续编译后，报以下错误:
Compiling (linux--Release-shared) \033[0;35mChaCha20Poly1305.c\033[0m
***/CarPlay_Plugin/AccessorySDK/PlatformPOSIX/../Support/ChaCha20Poly1305.c: In function '_chacha20_xor':
***/CarPlay_Plugin/AccessorySDK/PlatformPOSIX/../Support/ChaCha20Poly1305.c:584: error: subscripted value is neither array nor pointer
***/CarPlay_Plugin/AccessorySDK/PlatformPOSIX/../Support/ChaCha20Poly1305.c:585: error: subscripted value is neither array nor pointer
make[1]: *** [***/CarPlay_Plugin/PlatformPOSIX/../build/Release-linux/obj/ChaCha20Poly1305.so.o] Error 1
make[1]: Leaving directory `***/CarPlay_Plugin/AccessorySDK/PlatformPOSIX'
make: *** [***/CarPlay_Plugin/PlatformPOSIX/../build/Release-linux/libCoreUtils.so] Error 2
经过阅读代码和查阅网络资料后发现应该是cpu支持SIMD优化，但是编译器不支持，这里描述可能不准确，属于编译优化的问题，不够清楚，
但是修改ChaCha20Poly1305.c中的代码：
#if( TARGET_HAS_NEON || ( TARGET_HAS_SSE >= SSE_VERSION( 2, 0 ) ) )
    #define CHACHA20_SIMD        1
#else
    #define CHACHA20_SIMD        0
#endif
为：
//#if( TARGET_HAS_NEON || ( TARGET_HAS_SSE >= SSE_VERSION( 2, 0 ) ) )
//    #define CHACHA20_SIMD        1
//#else
    #define CHACHA20_SIMD        0
//#endif
即不使用CHACHA20_SIMD优化后，编译通过。

至此，所有的编译目标都已经被成功编译出，分别是以下文件：
airplayutil  libAirPlay.so  libAirPlaySupport.so  libAudioStream.so  libCoreUtils.so  libScreenStream.so