cocos2dxandroid运行Luac编译后的lua代码
运行环境
win7 64
cocos2d-2.1rc0-x-2.1.2
lua 5.1
通常我们编写好的lua代码都是明文形式，谁都可以查看修改，为了防止自己的劳动成果不被别人轻易的盗取，可以使用luac（lua库中自带）对其进行加密，转换为二进制文件。这样lua代码就无法直接查看，但是这里会有一个问题：在windows下能够很好的运行，在android上就会黑屏，提示错误：
[LUA ERROR] binary string: unexpected end in precompiled chunk
追根溯源
在bool AppDelegate::applicationDidFinishLaunching()中查看lua加载代码：
01.
#if (CC_TARGET_PLATFORM == CC_PLATFORM_ANDROID)
02.
CCString* pstrFileContent = CCString::createWithContentsOfFile( "program/main.lua" );
03.
if (pstrFileContent)
04.
{
05.
pEngine->executeString(pstrFileContent->getCString());
06.
}
07.
#else
08.
std::string path = CCFileUtils::sharedFileUtils()->fullPathForFilename( "program/main.lua" );
09.
pEngine->addSearchPath( path.substr( 0, path.find_last_of( "/" ) ).c_str() );
10.
pEngine->executeScriptFile( path.c_str() );
11.
#endif
这里executeString()加载lua文件，继续查看源码发现真正干活的是：
1.
LUALIB_API int luaL_loadbuffer (lua_State *L, const char *buff, size_t size,
2.
const char *name) {
3.
LoadS ls;
4.
ls.s = buff;
5.
ls.size = size;
6.
return lua_load(L, getS, &ls, name);
7.
}
在回头看看函数executeScriptFile()的执行过程：
01.
LUALIB_API int luaL_loadfile (lua_State *L, const char *filename) {
02.
LoadF lf;
03.
int status, readstatus;
04.
int c;
05.
int fnameindex = lua_gettop(L) + 1; /* index of filename on the stack */
06.
lf.extraline = 0;
07.
if (filename == NULL) {
08.
lua_pushliteral(L, "=stdin");
09.
lf.f = stdin;
10.
}
11.
else {
12.
lua_pushfstring(L, "@%s", filename);
13.
lf.f = fopen(filename, "r");
14.
if (lf.f == NULL) return errfile(L, "open", fnameindex);
15.
}
16.
c = getc(lf.f);
17.
if (c == '#') { /* Unix exec. file? */
18.
lf.extraline = 1;
19.
while ((c = getc(lf.f)) != EOF && c != '
20.
') ; /* skip first line */
21.
if (c == '
22.
') c = getc(lf.f);
23.
}
24.
if (c == LUA_SIGNATURE[0] && filename) { /* binary file? */
25.
lf.f = freopen(filename, "rb", lf.f); /* reopen in binary mode */
26.
if (lf.f == NULL) return errfile(L, "reopen", fnameindex);
27.
/* skip eventual `#!...' */
28.
while ((c = getc(lf.f)) != EOF && c != LUA_SIGNATURE[0]) ;
29.
lf.extraline = 0;
30.
}
31.
ungetc(c, lf.f);
32.
status = lua_load(L, getF, &lf, lua_tostring(L, -1)); // 关键，与luaL_loadbuffer()中的一样
33.
readstatus = ferror(lf.f);
34.
if (filename) fclose(lf.f); /* close file (even in case of errors) */
35.
if (readstatus) {
36.
lua_settop(L, fnameindex); /* ignore results from `lua_load' */
37.
return errfile(L, "read", fnameindex);
38.
}
39.
lua_remove(L, fnameindex);
40.
return status;
41.
}
解决办法
修改scriptingluacocos2dx_supportCocos2dxLuaLoader.cpp中的loader_Android()函数
修改前：
01.
int loader_"http://www.it165.net/pro/ydad/" target="_blank" class="keylink">Android(lua_State *L)
02.
{
03.
std::string filename(luaL_checkstring(L, 1));
04.
filename.append(".lua");
05.
06.
CCString* pFileContent = CCString::createWithContentsOfFile(filename.c_str());
07.
08.
if (pFileContent)
09.
{
10.
if (luaL_loadstring(L, pFileContent->getCString()) != 0)
11.
{
12.
luaL_error(L, "error loading module %s from file %s :
13.
%s",
14.
lua_tostring(L, 1), filename.c_str(), lua_tostring(L, -1));
15.
}
16.
}
17.
else
18.
{
19.
CCLog("can not get file data of %s", filename.c_str());
20.
}
21.
22.
return 1;
23.
}
修改后：
01.
int loader_Android(lua_State* L)
02.
{
03.
unsigned char* pData = nullptr;
04.
unsigned long size = 0;
05.
06.
/* modify for read lua script from bytecode */
07.
std::string filename(luaL_checkstring(L, 1));
08.
std::string rel_name = filename.append(".lua");
09.
10.
pData = CCFileUtils::sharedFileUtils()->getFileData(rel_name.c_str(), "rb", &size);
11.
if (pData) {
12.
if (luaL_loadbuffer(L, (char*)pData,size,rel_name.c_str()) != 0 ) {
13.
luaL_error(L, "error loading module s from file s :s",
14.
lua_tostring(L, 1), rel_name.c_str(), lua_tostring(L, -1));
15.
}
16.
}
17.
else {
18.
CCLog("can not get file data of %s", filename.c_str());
19.
}
20.
21.
CC_SAFE_DELETE_ARRAY(pData);
22.
23.
return 1;
24.
}
另外，由于在cpp中第一次加载lua并没有调用loader_Android()，这是因为uaL_loadbuffer只会把文件加载成为一个chunk，而不会运行该chunk，所以还要在加一条调用语名lua_pcall，如下：
01.
int loader_Android(lua_State* L)
02.
{
03.
unsigned char* pData = nullptr;
04.
unsigned long size = 0;
05.
06.
/* modify for read lua script from bytecode */
07.
std::string filename(luaL_checkstring(L, 1));
08.
std::string rel_name = filename.append(".lua");
09.
10.
pData = CCFileUtils::sharedFileUtils()->getFileData(rel_name.c_str(), "rb", &size);
11.
if (pData) {
12.
if (luaL_loadbuffer(L, (char*)pData,size,rel_name.c_str()) != 0 || lua_pcall(L, 0, LUA_MULTRET, 0) ) { // 修改处
13.
luaL_error(L, "error loading module s from file s :s",
14.
lua_tostring(L, 1), rel_name.c_str(), lua_tostring(L, -1));
15.
}
16.
}
17.
else {
18.
CCLog("can not get file data of %s", filename.c_str());
19.
}
20.
21.
CC_SAFE_DELETE_ARRAY(pData);
22.
23.
return 1;
24.
}
1.
pEngine->executeString("require "program/main""); // 注意这里的"
最后我们的AppDelegate::applicationDidFinishLaunching()大概就是这样的，
01.
const char* luaFile = "program/main.lua";
02.
#if (CC_TARGET_PLATFORM == CC_PLATFORM_ANDROID)
03.
std::string path = CCFileUtils::sharedFileUtils()->fullPathForFilename(luaFile);
04.
CCLog("path = %s", path.c_str());
05.
std::string subPath = path.substr(0, path.find_last_of("/"));
06.
CCLog("sub path = %s", subPath.c_str());
07.
08.
pEngine->addSearchPath(subPath.c_str());
09.
10.
std::vector searchPaths = CCFileUtils::sharedFileUtils()->getSearchPaths();
11.
searchPaths.insert(searchPaths.begin(), subPath);
12.
CCFileUtils::sharedFileUtils()->setSearchPaths(searchPaths);
13.
14.
pEngine->executeString("require "program/main""); // 注意这里的"
15.
#else
16.
std::string path = CCFileUtils::sharedFileUtils()->fullPathForFilename(luaFile);
17.
pEngine->addSearchPath( path.substr( 0, path.find_last_of( "/" ) ).c_str() );
18.
pEngine->executeScriptFile( path.c_str() );
19.
#endif
注：这里笔者偷鸡了一下。