1.version.manifest

版本配置主要是用于快速确定是否需要更新，如果project.manifest很大的话这个是很有必要的。

{
	// assets manager从这里下载所有的assets
    "packageUrl" : "http://example.com/assets_manager/TestScene/",// version.manifest
    "remoteVersionUrl" : "http://example.com/assets_manager/TestScene/version.manifest",// project.manifest
    "remoteManifestUrl" : "http://example.com/assets_manager/TestScene/project.manifest",// 本mani文件的版本
    "version" : "1.0.0",// 组版本
	"groupVersions": {
		"1" : "1.0.22"
	}
    "engineVersion" : "Cocos2d-JS v3.0 RC0"
}

bool Manifest::versionEquals(const Manifest *b) const
{
    // Check manifest version
    if (_version != b->getVersion())
    {
        return false;
    }
    // Check group versions
    else
    {
        std::vector<std::string> bGroups = b->getGroups();
        std::unordered_map<std::string,std::string> bGroupVer = b->getGroupVerions();
        // Check group size
        if (bGroups.size() != _groups.size())
            return false;
        
        // Check groups version
        for (int i = 0; i < _groups.size(); ++i) {
            std::string gid =_groups[i];
            // Check group name
            if (gid != bGroups[i])
                return false;
            // Check group version
            if (_groupVer.at(gid) != bGroupVer.at(gid))
                return false;
        }
    }
    return true;
}

2.project.manifest

apk里的project.manifest会和下载的project.manifest（如果更新过的话会cache在下载目录的）比较version，选择version大的版本。所以这里介绍服务器的project.manifest配置。

其他的和上面的一样，只是新加了assets和searchPaths字段，用于配置更新的文件及要设置的搜索目录。

{  
    "packageUrl" : "http://192.168.1.103/bw","remoteManifestUrl" : "http://192.168.1.103/bw/project.manifest","remoteVersionUrl" : "http://192.168.1.103/bw/version.manifest","version" : "1.0.22","groupVersions" : {  
        "1" : "1.0.22"  
    },"engineVersion" : "3.0 rc0","assets" : {  
        "app.zip" : {
			"md5" : "69361FEDE857D55A627B997828D63A0E","compressed" : true,"group" : "1"  
        }  
    },"searchPaths" : [
	]  
}

而客户端更新文件的方式是，比较本地（或cache过的）和从服务器下载的project.manifest文件的差值，然后进行更新。具体算法是比较assets的所有值，减少的就删除，

新增了就添加，md5变了就修改。所以目前没有用到group字段，当然你可以用来自己配置的时候区分各个组。具体比较代码：

std::unordered_map<std::string,Manifest::AssetDiff> Manifest::genDiff(const Manifest *b) const
{
    std::unordered_map<std::string,AssetDiff> diff_map;
    std::unordered_map<std::string,Asset> bAssets = b->getAssets();
    
    std::string key;
    Asset valueA;
    Asset valueB;
    std::unordered_map<std::string,Asset>::const_iterator valueIt,it;
    for (it = _assets.begin(); it != _assets.end(); ++it)
    {
        key = it->first;
        valueA = it->second;
        
        // Deleted
        valueIt = bAssets.find(key);
        if (valueIt == bAssets.cend()) {
            AssetDiff diff;
            diff.asset = valueA;
            diff.type = DiffType::DELETED;
            diff_map.emplace(key,diff);
            continue;
        }
        
        // Modified
        valueB = valueIt->second;
        if (valueA.md5 != valueB.md5) {
            AssetDiff diff;
            diff.asset = valueB;
            diff.type = DiffType::MODIFIED;
            diff_map.emplace(key,diff);
        }
    }
    
    for (it = bAssets.begin(); it != bAssets.end(); ++it)
    {
        key = it->first;
        valueB = it->second;
        
        // Added
        valueIt = _assets.find(key);
        if (valueIt == _assets.cend()) {
            AssetDiff diff;
            diff.asset = valueB;
            diff.type = DiffType::ADDED;
            diff_map.emplace(key,diff);
        }
    }
    
    return diff_map;
}