`cocos2dx非完整` 添加xxtea加密模块

时间：2015-05-26 20:30:03 阅读：517 评论：0 收藏：0 [点我收藏+]

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在上一篇文章中,我已经开始着手写自己的模块,也就是fw部分.其中上一篇文章中完成的是lua部分的配置解析部分,涉及一点点平台方面的封装.这一片文章我来说明一下我是如何处理cocos2dx资源加密的.首先需要说明白的是,资源是什么?资源分为哪几类?

在选择使用lua脚本开发后,包括lua文件,游戏美术资源,游戏的配置,我都统称为游戏资源,所以我期望的加密是能够加密所有这些东西.quick提供了xxtea,而cocos2dx也在luastack中整合了xxtea,我稍微做了一些修改.主要的修改思路是:首先要知道lua文件,游戏资源文件的加载入口在哪里.也许很多人听到我这么说会觉得很怪,不过这确实是解决这个问题的根本出发点.只要找到了加载入口才能做出合适的解决方案.

通过查看源码,我发现lua_loader加载lua文件的入口其实就是fileutils中的接口,然后使用vs的debug,又定位到fileutils中的文件Io读取接口.这样子就知道我们需要手动操作的接口了。我们就看其中一个接口就好了.

CCFileUtils-win32.cpp

 1 static Data getData(const std::string& filename, bool forString)
 2 {
 3     if (filename.empty())
 4     {
 5         return Data::Null;
 6     }
 7 
 8     unsigned char *buffer = nullptr;
 9 
10     size_t size = 0;
11     do
12     {
13         // read the file from hardware
14         std::string fullPath = FileUtils::getInstance()->fullPathForFilename(filename);
15 
16         WCHAR wszBuf[CC_MAX_PATH] = {0};
17         MultiByteToWideChar(CP_UTF8, 0, fullPath.c_str(), -1, wszBuf, sizeof(wszBuf)/sizeof(wszBuf[0]));
18 
19         HANDLE fileHandle = ::CreateFileW(wszBuf, GENERIC_READ, FILE_SHARE_READ, NULL, OPEN_EXISTING, NULL, nullptr);
20         CC_BREAK_IF(fileHandle == INVALID_HANDLE_VALUE);
21         
22         size = ::GetFileSize(fileHandle, nullptr);
23 
24         if (forString)
25         {
26             buffer = (unsigned char*) malloc(size + 1);
27             buffer[size] = ‘\0‘;
28         }
29         else
30         {
31             buffer = (unsigned char*) malloc(size);
32         }
33         DWORD sizeRead = 0;
34         BOOL successed = FALSE;
35         successed = ::ReadFile(fileHandle, buffer, size, &sizeRead, nullptr);
36         ::CloseHandle(fileHandle);
37 
38         if (!successed)
39         {
40             free(buffer);
41             buffer = nullptr;
42         }
43     } while (0);
44     
45     Data ret;
46 
47     if (buffer == nullptr || size == 0)
48     {
49         std::string msg = "Get data from file(";
50         // Gets error code.
51         DWORD errorCode = ::GetLastError();
52         char errorCodeBuffer[20] = {0};
53         snprintf(errorCodeBuffer, sizeof(errorCodeBuffer), "%d", errorCode);
54 
55         msg = msg + filename + ") failed, error code is " + errorCodeBuffer;
56         CCLOG("%s", msg.c_str());
57     }
58     else
59     { 
60         unsigned long len = 0;
61         unsigned char* retbuf = FWResEncrypt::getInstance()->decryptData(buffer, size, &len);
62         //ret.fastSet(buffer, size);
63         ret.fastSet(retbuf, len);
64     }
65     return ret;
66 }

如果读取文件成功的话,在62行中buffer保存的就是从文件读取的字符流. 所以如果资源文件是被加密的,那么我们只需要在这个时候进行相关的解密操作然后调用ret.fastSet接口传入解密后的字符就行了。也就是上面我修改的那几句代码,请具体参考源码文件对比.好了，知道这么做以后我们就去看一下xxtea的操作方式.xxtea是在external提供过得第三方扩展,其实这是一个比较旧的版本,不过引擎自带的,我也懒得去添加新的了.看下面我从CCLuaStack.cpp中截取的部分代码,观察一下xxtea加密接口的使用.

 1 int LuaStack::luaLoadBuffer(lua_State *L, const char *chunk, int chunkSize, const char *chunkName)
 2 {
 3     int r = 0;
 4     
 5     if (_xxteaEnabled && strncmp(chunk, _xxteaSign, _xxteaSignLen) == 0)
 6     {
 7         // decrypt XXTEA
 8         xxtea_long len = 0;
 9         unsigned char* result = xxtea_decrypt((unsigned char*)chunk + _xxteaSignLen,
10                                               (xxtea_long)chunkSize - _xxteaSignLen,
11                                               (unsigned char*)_xxteaKey,
12                                               (xxtea_long)_xxteaKeyLen,
13                                               &len);
14         r = luaL_loadbuffer(L, (char*)result, len, chunkName);
15         free(result);
16     }
17     else
18     {
19         r = luaL_loadbuffer(L, chunk, chunkSize, chunkName);
20     }

然后继续观察其他部分的使用,如xxtea签名的设置:

 1 void LuaStack::setXXTEAKeyAndSign(const char *key, int keyLen, const char *sign, int signLen)
 2 {
 3     cleanupXXTEAKeyAndSign();
 4     
 5     if (key && keyLen && sign && signLen)
 6     {
 7         _xxteaKey = (char*)malloc(keyLen);
 8         memcpy(_xxteaKey, key, keyLen);
 9         _xxteaKeyLen = keyLen;
10         
11         _xxteaSign = (char*)malloc(signLen);
12         memcpy(_xxteaSign, sign, signLen);
13         _xxteaSignLen = signLen;
14         
15         _xxteaEnabled = true;
16     }
17     else
18     {
19         _xxteaEnabled = false;
20     }
21 }
22 
23 void LuaStack::cleanupXXTEAKeyAndSign()
24 {
25     if (_xxteaKey)
26     {
27         free(_xxteaKey);
28         _xxteaKey = nullptr;
29         _xxteaKeyLen = 0;
30     }
31     if (_xxteaSign)
32     {
33         free(_xxteaSign);
34         _xxteaSign = nullptr;
35         _xxteaSignLen = 0;
36     }
37 }

好了,有了这些作为基础,我们可以动手写自己的加密管理类了。为什么说要另外写,很多人第一反应可能是在引擎中添加更方便.不可那么做，第一,不应该随便修改引擎核心部分的源码,除非迫不得已.第二,我们这边的情况确实不应该在libluacocos2dx vs项目中去做.因为libluacocos2dx对libcocos2dx是依赖关系,不应该前后倒置。所以第一步是用VS打开项目解决方案.然后在libcocos2dx extern筛选器下面再添加一个删选器,命名为xxtea,然后加入cocos2dx/extern/xxtea下面的xxtea第三方依赖源码.第二步,由于fileutils涉及到跨平台部分,所以我们应该提供一个加密操作类，放在cocos/platform下面是我认为比较合适的位置.所以我添加了如下的源码:

 1 #ifndef __firework_ResEncrypt__
 2 #define __firework_ResEncrypt__
 3 
 4 #include "platform/CCPlatformMacros.h"
 5 
 6 class CC_DLL FWResEncrypt
 7 {
 8 public:
 9     static FWResEncrypt* getInstance();
10 
11 public:
12     unsigned char* decryptData(unsigned char* buf, unsigned long size, unsigned long *pSize);
13     unsigned char* getFileData(const char* fileName, const char* mode, unsigned long *pSize);
14     unsigned char* encryptData(unsigned char* buf, unsigned long size, unsigned long *pSize);
15     void setXXTeaKeyAndSign(const char* xxteaKey, int xxteaKeyLen, const char* xxteaSign, int xxteaSignLen);
16     void cleanupXXTeaKeyAndSign();
17 private:
18     static FWResEncrypt* pFWResEncrypt_;
19 
20     bool xxteaEnabled_;
21     char* xxteaKey_;
22     int xxteaKeyLen_;
23     char* xxteaSign_;
24     int xxteaSignLen_;
25 private:
26     FWResEncrypt();
27     FWResEncrypt(const FWResEncrypt&);
28     FWResEncrypt& operator = (const FWResEncrypt&);
29 };
30 
31 #endif

#include "FWResEncrypt.h"
#include "cocos2d.h"
#include "CCFileUtils.h"
#include "xxtea/xxtea.h"

FWResEncrypt* FWResEncrypt::pFWResEncrypt_ = nullptr;

FWResEncrypt* FWResEncrypt::getInstance()
{
    if(!pFWResEncrypt_) 
    {
        pFWResEncrypt_ = new FWResEncrypt();
    }
    return pFWResEncrypt_;
}

FWResEncrypt::FWResEncrypt()
    :xxteaEnabled_(false)
    ,xxteaKey_(nullptr)
    ,xxteaKeyLen_(0)
    ,xxteaSign_(nullptr)
    ,xxteaSignLen_(0)
{

}

void FWResEncrypt::setXXTeaKeyAndSign(const char* xxteaKey, int xxteaKeyLen, const char* xxteaSign, int xxteaSignLen)
{
    cleanupXXTeaKeyAndSign();

    if( xxteaKey && xxteaKeyLen && xxteaSign && xxteaSignLen) 
    {
        xxteaKey_ = (char*)malloc(xxteaKeyLen);
        memcpy(xxteaKey_, xxteaKey, xxteaKeyLen);
        xxteaKeyLen_ = xxteaKeyLen;

        xxteaSign_ = (char*)malloc(xxteaSignLen);
        memcpy(xxteaSign_, xxteaSign, xxteaSignLen);
        xxteaSignLen_ = xxteaSignLen;

        xxteaEnabled_ = true;
    } else
    {
        xxteaEnabled_ = false;
    }
}

void FWResEncrypt::cleanupXXTeaKeyAndSign()
{
    if(xxteaKey_)
    {
        free(xxteaKey_);
        xxteaKey_ = nullptr;
        xxteaKeyLen_ = 0;
    }
    if(xxteaSign_)
    {
        free(xxteaSign_);
        xxteaSign_ = nullptr;
        xxteaSignLen_ = 0;
    }
}

unsigned char* FWResEncrypt::getFileData(const char* fileName, const char* mode, unsigned long* pSize)
{
    ssize_t size;
    unsigned char* buf = cocos2d::FileUtils::getInstance()->getFileData(fileName, mode, &size);
    if(nullptr == buf)
    {
        return nullptr;
    }

    unsigned char* buffer = nullptr;
    FWResEncrypt* pFWResEncrypt = FWResEncrypt::getInstance();

    bool isXXTEA = pFWResEncrypt && pFWResEncrypt->xxteaEnabled_;

    for(unsigned int i = 0; isXXTEA && i < pFWResEncrypt->xxteaSignLen_ && i < size; ++ i )
    {
        isXXTEA = buf[i] == pFWResEncrypt->xxteaSign_[i];
    }

    if(isXXTEA)
    {
        xxtea_long len = 0;
        buffer = xxtea_decrypt(    buf+pFWResEncrypt->xxteaSignLen_,
            (xxtea_long)size - (xxtea_long)pFWResEncrypt->xxteaSignLen_,
            (unsigned char*)pFWResEncrypt->xxteaKey_,
            (xxtea_long)pFWResEncrypt->xxteaKeyLen_, &len);
        delete [] buf;
        buf = nullptr;
        size = len;
    } else 
    {
        buffer = buf;
    }

    if(pSize)
    {
        *pSize = size;
    }
    return buffer;
}

unsigned char *FWResEncrypt::decryptData(unsigned char* buf, unsigned long size, unsigned long* pSize)
{
    CCAssert(buf != nullptr, "decryptData buf cannot nullptr");

    unsigned char* buffer = nullptr;
    FWResEncrypt* pFWResEncrypt = FWResEncrypt::getInstance();
    bool isXXTEA = pFWResEncrypt && pFWResEncrypt->xxteaEnabled_;

    for(unsigned int i = 0; isXXTEA && i < pFWResEncrypt->xxteaSignLen_ && i < size; ++ i )
    {
        isXXTEA = buf[i] == pFWResEncrypt->xxteaSign_[i];
    }

    if(isXXTEA)
    {
        xxtea_long len = 0;
        buffer = xxtea_decrypt(    buf+pFWResEncrypt->xxteaSignLen_,
            (xxtea_long)size - (xxtea_long)pFWResEncrypt->xxteaSignLen_,
            (unsigned char*)pFWResEncrypt->xxteaKey_,
            (xxtea_long)pFWResEncrypt->xxteaKeyLen_, &len);
        delete [] buf;
        buf = nullptr;
        size = len;
    } else
    {
        buffer = buf;
    }
    if(pSize)
    {
        *pSize = size;
    }
    return buffer;
}

unsigned char* FWResEncrypt::encryptData(unsigned char* buf, unsigned long size, unsigned long* pSize)
{
    CCAssert(buf != nullptr, "encryptData buf cannot nullptr");
    unsigned char* buffer = nullptr;
    unsigned char* ret = nullptr;
    FWResEncrypt* pFWResEncrypt = FWResEncrypt::getInstance();
    bool isXXTEA = pFWResEncrypt && pFWResEncrypt->xxteaEnabled_;
    for(unsigned int i = 0; isXXTEA && i < pFWResEncrypt->xxteaSignLen_ && i < size; ++ i )
    {
        isXXTEA = buf[i] == pFWResEncrypt->xxteaSign_[i];
    }
    if(!isXXTEA)
    {
        xxtea_long len = 0;
        buffer = xxtea_encrypt(    buf,
            (xxtea_long)size,
            (unsigned char*)pFWResEncrypt->xxteaKey_,
            (xxtea_long)pFWResEncrypt->xxteaKeyLen_, &len);
        delete [] buf;
        buf = nullptr;
        size = len;
        ret = (unsigned char*)malloc(size+pFWResEncrypt->xxteaSignLen_+1);
        memcpy(ret, pFWResEncrypt->xxteaSign_, pFWResEncrypt->xxteaSignLen_);
        memcpy(ret+pFWResEncrypt->xxteaSignLen_, buffer, size);
        ret[len+pFWResEncrypt->xxteaSignLen_] = ‘\0‘;
    } else
    {
        ret = buf;
    }
    if(pSize)
    {
        *pSize = size+pFWResEncrypt->xxteaSignLen_;
    }
    return ret;
}

其中设置签名,清除签名那些方法我都是直接从CCLuaStack中拿过来的,加密接口也可以直接从那边改一下就好了,最主要的是decryptData这个接口,也就是解密接口. 我发现xxtea提供的sign的功能就是用来同时解析加密和非加密文件,也就是直接加载文件头.如果我的Sign是FW的话,那么我会发现我加密后文件头就有FW.所以加密接口实现的思路是使用xxtea加密,得到加密后的字符串,再做字符串操作,将Sign拼接到加密字符串前面,也就是生成一个新的字符串,再写入文件流就行了.好了,下面我给出我绑定接口到lua的源码:

 1 #include "lua_fw_encrypt.h"
 2 #if __cplusplus
 3 extern "C" {
 4 #endif
 5 #include <lualib.h>
 6 #include <lauxlib.h>
 7 #if __cplusplus
 8 }
 9 #endif
10 
11 #include <string>
12 #include "FWResEncrypt.h"
13 #include "cocos2d.h"
14 int
15 lua_fw_encrypt_encryptData(lua_State* lua_state)
16 {
17     std::string data = lua_tostring(lua_state, 1);
18     unsigned char* encryptData = (unsigned char*)malloc(data.size());
19     memcpy(encryptData, data.c_str(), data.size());
20     unsigned long len = 0;
21     unsigned char* encryptedData = FWResEncrypt::getInstance()->encryptData(encryptData, data.size(), &len);
22     lua_pushlstring(lua_state, (char*)encryptedData, len);
23     return 1;
24 }
25 int
26 lua_fw_encrypt_decryptData(lua_State* lua_state)
27 {
28     size_t len = 0;
29     const char *data = lua_tolstring(lua_state, 1,&len);
30     unsigned char* decryptData = (unsigned char*)malloc(len);
31     memcpy(decryptData, data, len);
32     unsigned char* decryptedData = FWResEncrypt::getInstance()->decryptData(decryptData, len, nullptr);
33     lua_pushstring(lua_state, (char*)decryptedData);
34     return 1;
35 }
36 
37 namespace fw {
38     const luaL_Reg
39     g_fw_encrypt_funcs[] = {
40         {"encrypt_data", lua_fw_encrypt_encryptData},
41         {"decrypt_data", lua_fw_encrypt_decryptData},
42         {nullptr,nullptr},
43     };
44 
45     void 
46     register_fw_encrypt(lua_State* lua_state) {
47         luaL_register(lua_state, "fw.encrypt", g_fw_encrypt_funcs);
48     }
49 }

我并不喜欢cocos2dx使用的tolua++的方式绑定接口,会生成太多冗余的代码,而是采用传统的C方式去做这件事情,这里面注意lua_pushlstring的使用,为什么要用这个接口?而不是直接使用lua_pushstring.这个问题可能是因为引擎绑定的lua源码中做了一些修改(我是这样推测的)，因为使用lua_pushstring错误,应该是不能正确获取指针指向的字符长度.改用lua_pushlstring传入长度len就可以解决这个问题了.

下面也是我在lua那边fw模块做了一下简单的包装，非常的简单.这么做的目的就是能够让使用lua的人不关心c++部分的实现，不会觉得这个接口出现的莫名其妙．

1 --小岩<757011285@qq.com>
2 --2015-5-26 16:45
3 return 
4 {
5      encrypt = fw.encrypt.encrypt_data,
6      decrypt = fw.encrypt.decrypt_data,    
7 }

好了，有了这个加解密的接口,我们就可以在配置文件读取的那部分做一下修改,在持久化和读取的时候就可以正确读取了.如果是windows需要修改platform下面ccFileutils-win32.cpp中的接口,如果是android则对用修改ccFileutils-android.cpp中的接口.我给一下源码:(android同样):

  1 /****************************************************************************
  2 Copyright (c) 2010-2012 cocos2d-x.org
  3 Copyright (c) 2013-2014 Chukong Technologies Inc.
  4 
  5 http://www.cocos2d-x.org
  6 
  7 Permission is hereby granted, free of charge, to any person obtaining a copy
  8 of this software and associated documentation files (the "Software"), to deal
  9 in the Software without restriction, including without limitation the rights
 10 to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
 11 copies of the Software, and to permit persons to whom the Software is
 12 furnished to do so, subject to the following conditions:
 13 
 14 The above copyright notice and this permission notice shall be included in
 15 all copies or substantial portions of the Software.
 16 
 17 THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
 18 IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
 19 FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
 20 AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
 21 LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
 22 OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
 23 THE SOFTWARE.
 24 ****************************************************************************/
 25 
 26 #include "platform/CCPlatformConfig.h"
 27 #if CC_TARGET_PLATFORM == CC_PLATFORM_WIN32
 28 
 29 #include "CCFileUtils-win32.h"
 30 #include "platform/CCCommon.h"
 31 #include <Shlobj.h>
 32 #include "FWResEncrypt.h"
 33 using namespace std;
 34 
 35 NS_CC_BEGIN
 36 
 37 #define CC_MAX_PATH  512
 38 
 39 // The root path of resources, the character encoding is UTF-8.
 40 // UTF-8 is the only encoding supported by cocos2d-x API.
 41 static std::string s_resourcePath = "";
 42 
 43 // D:\aaa\bbb\ccc\ddd\abc.txt --> D:/aaa/bbb/ccc/ddd/abc.txt
 44 static inline std::string convertPathFormatToUnixStyle(const std::string& path)
 45 {
 46     std::string ret = path;
 47     int len = ret.length();
 48     for (int i = 0; i < len; ++i)
 49     {
 50         if (ret[i] == ‘\\‘)
 51         {
 52             ret[i] = ‘/‘;
 53         }
 54     }
 55     return ret;
 56 }
 57 
 58 static void _checkPath()
 59 {
 60     if (0 == s_resourcePath.length())
 61     {
 62         WCHAR utf16Path[CC_MAX_PATH] = {0};
 63         GetCurrentDirectoryW(sizeof(utf16Path)-1, utf16Path);
 64         
 65         char utf8Path[CC_MAX_PATH] = {0};
 66         int nNum = WideCharToMultiByte(CP_UTF8, 0, utf16Path, -1, utf8Path, sizeof(utf8Path), nullptr, nullptr);
 67 
 68         s_resourcePath = convertPathFormatToUnixStyle(utf8Path);
 69         s_resourcePath.append("/");
 70     }
 71 }
 72 
 73 FileUtils* FileUtils::getInstance()
 74 {
 75     if (s_sharedFileUtils == nullptr)
 76     {
 77         s_sharedFileUtils = new FileUtilsWin32();
 78         if(!s_sharedFileUtils->init())
 79         {
 80           delete s_sharedFileUtils;
 81           s_sharedFileUtils = nullptr;
 82           CCLOG("ERROR: Could not init CCFileUtilsWin32");
 83         }
 84     }
 85     return s_sharedFileUtils;
 86 }
 87 
 88 FileUtilsWin32::FileUtilsWin32()
 89 {
 90 }
 91 
 92 bool FileUtilsWin32::init()
 93 {
 94     _checkPath();
 95     _defaultResRootPath = s_resourcePath;
 96     return FileUtils::init();
 97 }
 98 
 99 bool FileUtilsWin32::isFileExistInternal(const std::string& strFilePath) const
100 {
101     if (0 == strFilePath.length())
102     {
103         return false;
104     }
105     
106     std::string strPath = strFilePath;
107     if (!isAbsolutePath(strPath))
108     { // Not absolute path, add the default root path at the beginning.
109         strPath.insert(0, _defaultResRootPath);
110     }
111 
112     WCHAR utf16Buf[CC_MAX_PATH] = {0};
113     MultiByteToWideChar(CP_UTF8, 0, strPath.c_str(), -1, utf16Buf, sizeof(utf16Buf)/sizeof(utf16Buf[0]));
114 
115     DWORD attr = GetFileAttributesW(utf16Buf);
116     if(attr == INVALID_FILE_ATTRIBUTES || (attr & FILE_ATTRIBUTE_DIRECTORY))
117         return false;   //  not a file
118     return true;
119 }
120 
121 bool FileUtilsWin32::isAbsolutePath(const std::string& strPath) const
122 {
123     if (   strPath.length() > 2 
124         && ( (strPath[0] >= ‘a‘ && strPath[0] <= ‘z‘) || (strPath[0] >= ‘A‘ && strPath[0] <= ‘Z‘) )
125         && strPath[1] == ‘:‘)
126     {
127         return true;
128     }
129     return false;
130 }
131 
132 static Data getData(const std::string& filename, bool forString)
133 {
134     if (filename.empty())
135     {
136         return Data::Null;
137     }
138 
139     unsigned char *buffer = nullptr;
140 
141     size_t size = 0;
142     do
143     {
144         // read the file from hardware
145         std::string fullPath = FileUtils::getInstance()->fullPathForFilename(filename);
146 
147         WCHAR wszBuf[CC_MAX_PATH] = {0};
148         MultiByteToWideChar(CP_UTF8, 0, fullPath.c_str(), -1, wszBuf, sizeof(wszBuf)/sizeof(wszBuf[0]));
149 
150         HANDLE fileHandle = ::CreateFileW(wszBuf, GENERIC_READ, FILE_SHARE_READ, NULL, OPEN_EXISTING, NULL, nullptr);
151         CC_BREAK_IF(fileHandle == INVALID_HANDLE_VALUE);
152         
153         size = ::GetFileSize(fileHandle, nullptr);
154 
155         if (forString)
156         {
157             buffer = (unsigned char*) malloc(size + 1);
158             buffer[size] = ‘\0‘;
159         }
160         else
161         {
162             buffer = (unsigned char*) malloc(size);
163         }
164         DWORD sizeRead = 0;
165         BOOL successed = FALSE;
166         successed = ::ReadFile(fileHandle, buffer, size, &sizeRead, nullptr);
167         ::CloseHandle(fileHandle);
168 
169         if (!successed)
170         {
171             free(buffer);
172             buffer = nullptr;
173         }
174     } while (0);
175     
176     Data ret;
177 
178     if (buffer == nullptr || size == 0)
179     {
180         std::string msg = "Get data from file(";
181         // Gets error code.
182         DWORD errorCode = ::GetLastError();
183         char errorCodeBuffer[20] = {0};
184         snprintf(errorCodeBuffer, sizeof(errorCodeBuffer), "%d", errorCode);
185 
186         msg = msg + filename + ") failed, error code is " + errorCodeBuffer;
187         CCLOG("%s", msg.c_str());
188     }
189     else
190     { 
191         unsigned long len = 0;
192         unsigned char* retbuf = FWResEncrypt::getInstance()->decryptData(buffer, size, &len);
193         //ret.fastSet(buffer, size);
194         ret.fastSet(retbuf, len);
195     }
196     return ret;
197 }
198 
199 std::string FileUtilsWin32::getStringFromFile(const std::string& filename)
200 {
201     Data data = getData(filename, true);
202     if (data.isNull())
203     {
204         return "";
205     }
206 
207     std::string ret((const char*)data.getBytes());
208     return ret;
209 }
210     
211 Data FileUtilsWin32::getDataFromFile(const std::string& filename)
212 {
213     return getData(filename, false);
214 }
215 
216 unsigned char* FileUtilsWin32::getFileData(const std::string& filename, const char* mode, ssize_t* size)
217 {
218     unsigned char * pBuffer = nullptr;
219     *size = 0;
220     do
221     {
222         // read the file from hardware
223         std::string fullPath = fullPathForFilename(filename);
224 
225         WCHAR wszBuf[CC_MAX_PATH] = {0};
226         MultiByteToWideChar(CP_UTF8, 0, fullPath.c_str(), -1, wszBuf, sizeof(wszBuf)/sizeof(wszBuf[0]));
227 
228         HANDLE fileHandle = ::CreateFileW(wszBuf, GENERIC_READ, FILE_SHARE_READ, NULL, OPEN_EXISTING, NULL, nullptr);
229         CC_BREAK_IF(fileHandle == INVALID_HANDLE_VALUE);
230         
231         *size = ::GetFileSize(fileHandle, nullptr);
232 
233         pBuffer = (unsigned char*) malloc(*size);
234         DWORD sizeRead = 0;
235         BOOL successed = FALSE;
236         successed = ::ReadFile(fileHandle, pBuffer, *size, &sizeRead, nullptr);
237         ::CloseHandle(fileHandle);
238 
239         if (!successed)
240         {
241             free(pBuffer);
242             pBuffer = nullptr;
243         }
244     } while (0);
245     
246     if (! pBuffer)
247     {
248         std::string msg = "Get data from file(";
249         // Gets error code.
250         DWORD errorCode = ::GetLastError();
251         char errorCodeBuffer[20] = {0};
252         snprintf(errorCodeBuffer, sizeof(errorCodeBuffer), "%d", errorCode);
253 
254         msg = msg + filename + ") failed, error code is " + errorCodeBuffer;
255         CCLOG("%s", msg.c_str());
256     }
257     //return pBuffer;
258     return FWResEncrypt::getInstance()->decryptData(pBuffer, *size, (unsigned long*)size);
259 }
260 
261 std::string FileUtilsWin32::getPathForFilename(const std::string& filename, const std::string& resolutionDirectory, const std::string& searchPath)
262 {
263     std::string unixFileName = convertPathFormatToUnixStyle(filename);
264     std::string unixResolutionDirectory = convertPathFormatToUnixStyle(resolutionDirectory);
265     std::string unixSearchPath = convertPathFormatToUnixStyle(searchPath);
266 
267     return FileUtils::getPathForFilename(unixFileName, unixResolutionDirectory, unixSearchPath);
268 }
269 
270 std::string FileUtilsWin32::getFullPathForDirectoryAndFilename(const std::string& strDirectory, const std::string& strFilename)
271 {
272     std::string unixDirectory = convertPathFormatToUnixStyle(strDirectory);
273     std::string unixFilename = convertPathFormatToUnixStyle(strFilename);
274     
275     return FileUtils::getFullPathForDirectoryAndFilename(unixDirectory, unixFilename);
276 }
277 
278 string FileUtilsWin32::getWritablePath() const
279 {
280     // Get full path of executable, e.g. c:\Program Files (x86)\My Game Folder\MyGame.exe
281     char full_path[CC_MAX_PATH + 1];
282     ::GetModuleFileNameA(nullptr, full_path, CC_MAX_PATH + 1);
283 
284     // Debug app uses executable directory; Non-debug app uses local app data directory
285 //#ifndef _DEBUG
286         // Get filename of executable only, e.g. MyGame.exe
287         char *base_name = strrchr(full_path, ‘\\‘);
288 
289         if(base_name)
290         {
291             char app_data_path[CC_MAX_PATH + 1];
292 
293             // Get local app data directory, e.g. C:\Documents and Settings\username\Local Settings\Application Data
294             if (SUCCEEDED(SHGetFolderPathA(nullptr, CSIDL_LOCAL_APPDATA, nullptr, SHGFP_TYPE_CURRENT, app_data_path)))
295             {
296                 string ret((char*)app_data_path);
297 
298                 // Adding executable filename, e.g. C:\Documents and Settings\username\Local Settings\Application Data\MyGame.exe
299                 ret += base_name;
300 
301                 // Remove ".exe" extension, e.g. C:\Documents and Settings\username\Local Settings\Application Data\MyGame
302                 ret = ret.substr(0, ret.rfind("."));
303 
304                 ret += "\\";
305 
306                 // Create directory
307                 if (SUCCEEDED(SHCreateDirectoryExA(nullptr, ret.c_str(), nullptr)))
308                 {
309                     return convertPathFormatToUnixStyle(ret);
310                 }
311             }
312         }
313 //#endif // not defined _DEBUG
314 
315     // If fetching of local app data directory fails, use the executable one
316     string ret((char*)full_path);
317 
318     // remove xxx.exe
319     ret =  ret.substr(0, ret.rfind("\\") + 1);
320 
321     ret = convertPathFormatToUnixStyle(ret);
322 
323     return ret;
324 }
325 
326 NS_CC_END
327 
328 #endif // CC_TARGET_PLATFORM == CC_PLATFORM_WIN32

当我们使用cc.FileUtils:getInstance():getStringFromFile()读取文件内容的时候就获取到的是解密后的内容了,这个解密的过程是在引擎层面做好的了,也可以说对使用者来说是透明的.这样也是契合了为什么在前一篇文章中我为什么会说我坚持使用这个接口作为配置文件读取的主要原因.同样,如果是加密图片,plist文件,只需要按照一般我们使用过的方式使用就好了,不需要做任何的改动.

加密工具可以去下载一份quick的源码,里面有提供一个pack_files.bat脚本,用它来打包就好了,然后在引擎启动的时候设置好我们的签名,如下:

 1 bool AppDelegate::applicationDidFinishLaunching()
 2 {
 3     auto engine = LuaEngine::getInstance();
 4     ScriptEngineManager::getInstance()->setScriptEngine(engine);
 5     lua_State* L = engine->getLuaStack()->getLuaState();
 6     lua_module_register(L);
 7 
 8     cocos2d::FileUtils::getInstance()->setPopupNotify(false);
 9     
10     FWResEncrypt::getInstance()->setXXTeaKeyAndSign("RESPAWN", strlen("RESPAWN"), "FW", strlen("FW"));
11     engine->getLuaStack()->setXXTEAKeyAndSign("RESPAWN", strlen("RESPAWN"), "FW", strlen("FW"));
12     
13     // If you want to use Quick-Cocos2d-X, please uncomment below code
14     // register_all_quick_manual(L);
15     if (engine->executeScriptFile("src/main.lua")) {
16         return false;
17     }
18 
19     return true;
20 }

好吧,到这里就结束了.下一篇文章考虑可能会做一下增量动态更新,敬请期待.欢迎交流.我好久没用我的github了,待我稍微整理一下,然后以合适的方式上传我的代码,开源给大家.另外,我现在在找相关游戏资源,期望是整套的网游资源,要不然我也就只能做做这些架构方面的事情了,涉及不到游戏的业务逻辑.

`cocos2dx非完整` 添加xxtea加密模块

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原文地址：http://www.cnblogs.com/respawn/p/4531201.html

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