克隆git回购（深入） [英] Clone a git repo (in depth)

问题描述

如何克隆回购（使用 libgit2 ）

我想要做的只是 git clone ，但是使用 libgit2 。我可能会问的是 git clone 确实深入。

这就是我所做的远：

1. 初始化回购


2. 调整配置文件以添加远程


3. 创建 git_remote


4. 下载packfile packfile并写入索引（给我们一个.idx文件）
   
5. （编辑）将所有不同的分支写入磁盘。


6. git checkout 以某种方式。

现在我没有想法该怎么做。我唯一的猜测就是将 .idx 加载到 git_index 并使用 git_repository_set_index ，但没有显示任何文件。

编辑

我在半克隆​​的回购库上测试了运行 git checkout master ，并且完成了这项工作。现在我只需要找出如何使用libgit2来做到这一点，似乎问题跟踪器中有一些有用的信息。

编辑2

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现在我将添加我当前的代码，希望有人某天会发现它有用，希望能成为我从未找到的快速启动代码。注意：我在这里使用 Obj-C 和 Objective-Git ，但主要是纯c。

  +（GTRepository *）cloneFromRemoteURL：（NSURL *）remoteURL toLocalURL：（NSURL *）localURL 
 {
 / /让我们假设这个URL如下所示：https://github.com/libgit2/libgit2.git 
 //然后我们需要得到一个这样的URL：git：//github.com/libgit2/libgit2。 git 
 //这可能有点狡猾，但它现在会做。 
 const char * gitURL = [remoteURL.absoluteString stringByReplacingOccurrencesOfString：@https://github.com/withString：@git：//github.com/] .UTF8String; 
 
 //安装
 int错误; 
 git_repository * repo 
 git_config * cfg; 
 git_remote * remote; 
 
 NSURL * gitDirURL = [localURL URLByAppendingPathComponent：@。git]; 
 
 error = git_repository_open（& repo，gitDirURL.path.UTF8String）; 
 if（error！= GIT_SUCCESS）{
 
 git_repository_init（& repo，gitDirURL.path.UTF8String，1）; 
 
 //配置
 git_repository_config（& cfg，repo）; 
 git_config_set_int32（cfg，core.repositoryformatversion，0）; 
 git_config_set_bool（cfg，core.filemode，1）; 
 git_config_set_bool（cfg，core.bare，0）; 
 git_config_set_bool（cfg，core.logallrefupdates，1）; 
 git_config_set_bool（cfg，core.ignorecase，1）; 
 git_config_set_string（cfg，remote.origin.url，gitURL）; 
 git_config_set_string（cfg，remote.origin.fetch，+ refs / heads / *：refs / remotes / origin / *）; 
 git_config_set_string（cfg，branch.master.remote，origin）; 
 git_config_set_string（cfg，branch.master.merge，refs / heads / master）; 
 
 git_repository_set_workdir（repo，localURL.path.UTF8String）; 
 
 error = git_remote_new（& remote，repo，remote，gitURL，origin）; 
 
 git_repository_free（repo）; 
 git_repository_open（& repo，localURL.path.UTF8String）; 
} 
 
 
 
 git_repository_config（& cfg，repo）; 
 
 //连接到repo 
 error = git_remote_load（& remote，repo，origin）; 
 
 error = git_remote_connect（remote，GIT_DIR_FETCH）; 
 //获取包文件
 
 git_off_t bytes; 
 git_indexer_stats stats; 
 error = git_remote_download（remote，& bytes，& stats）; 
 
 NSURL * packFolderURL = [localURL URLByAppendingPathComponent：@。git / objects / pack]; 
 NSFileManager * fileManager = [NSFileManager defaultManager]; 
 NSArray * array = [fileManager contentsOfDirectoryAtURL：packFolderURL includesPropertiesForKeys：nil options：0 error：nil]; 
 NSLog（@Dictionary：％@，array）; 
 NSString *结果; 
 for（NSURL * url in array）{
 if（[url.path rangeOfString：@。pack]。location！= NSNotFound）{
 result = url.path; 
} 
} 
 const char * packname = [result UTF8String]; 
 
 
 //解包文件
 if（packname！= NULL）
 {
 git_indexer * indexer; 
 git_indexer_stats stats2; 
 int错误; 
 char hash [GIT_OID_HEXSZ + 1] = {0}; 
 
 error = git_indexer_new（&indexer，packname）; 
 error = git_indexer_run（indexer，& stats2）; 
 error = git_indexer_write（indexer）; 
 
 //获取packfile的散列（应该变成文件名）
 git_oid_fmt（hash，git_indexer_hash（indexer））; 
 
 NSString * hashStr = [NSString stringWithCString：hash encoding：NSUTF8StringEncoding]; 
 hashStr = [NSString stringWithFormat：@pack  - ％@。idx，hashStr]; 
 const char * indexPath = [hashStr UTF8String]; 
 
 puts（hash）; 
 git_index * index; 
 git_index_open（& index，indexPath）; 
 git_index_read（index）; 
 git_repository_set_index（repo，index）; 
 
 
 git_indexer_free（indexer）; 
 git_remote_update_tips（remote，update_cb2）; //不知道它做了什么，但它看起来很重要......它确实使分支出现在.git / refs / remotes / origin 
 
} 
  

//以某种方式在这里执行git checkout master

 返回[GTRepository repositoryWithURL：localURL error：nil]; 
 
 
 
 
解决方案
由于libgit2不会在其 https://github.com/libgit2/libgit2/issuesrel =nofollow>问题列表，其中一个关键是在原始git项目的源代码中： 
 
 
 
 
   builtin / clone.c   
 
 
   contrib / examples / git-clone.sh   
 
 
 
 
最后一个脚本将指导您完成 git clone 的所有阶段。
 
How to clone a repo (with libgit2)

I want to do exactly what git clone does but with libgit2. What I may be asking is what git clone really does in depth.

This is what I'm doing so far:

Initialize a repo
Adjust the config file to add the remote
Create a git_remote
Download a packfile
Index the packfile and write the index (gives us a .idx file)
(edit) Write all the different branches to disk.
(edit) Do git checkout in some way.
And now I have no idea what to do. My only guess would be to load the .idx to a git_index and use git_repository_set_index, but that didn't show any files either.

Edit

I tested running git checkout master on the half-cloned repo, and that did the job. Now I just need to find out how to do it with libgit2, and it seems like there is some useful information in the issue tracker.

Edit 2 

I will now add my current code, in hope that someone someday will find it useful, in hope to be that quick-start code I never found. Note: I'm using Obj-C and Objective-Git here, but it's mainly plain c.
+ (GTRepository *)cloneFromRemoteURL:(NSURL *)remoteURL toLocalURL:(NSURL *)localURL
{   
// Let's suppose the URL looks like: https://github.com/libgit2/libgit2.git
// Then we need to get a URL like this too: git://github.com/libgit2/libgit2.git
// This may be a bit dodgy, but it will do for now.
const char *gitURL = [remoteURL.absoluteString stringByReplacingOccurrencesOfString:@"https://github.com/" withString:@"git://github.com/"].UTF8String;

//Setup
int error;
git_repository *repo
git_config *cfg;
git_remote *remote;

NSURL *gitDirURL = [localURL URLByAppendingPathComponent:@".git"];

error = git_repository_open(&repo, gitDirURL.path.UTF8String);
    if (error != GIT_SUCCESS) {

    git_repository_init(&repo, gitDirURL.path.UTF8String, 1);

    //Config
    git_repository_config(&cfg, repo);
    git_config_set_int32 (cfg, "core.repositoryformatversion", 0);
    git_config_set_bool (cfg, "core.filemode", 1);
    git_config_set_bool (cfg, "core.bare", 0);
    git_config_set_bool (cfg, "core.logallrefupdates", 1);
    git_config_set_bool (cfg, "core.ignorecase", 1);
    git_config_set_string (cfg, "remote.origin.url", gitURL);
    git_config_set_string (cfg, "remote.origin.fetch", "+refs/heads/*:refs/remotes/origin/*");
    git_config_set_string (cfg, "branch.master.remote", "origin");
    git_config_set_string (cfg, "branch.master.merge", "refs/heads/master");

    git_repository_set_workdir(repo, localURL.path.UTF8String);

    error = git_remote_new(&remote, repo, "A remote", gitURL, "origin");

    git_repository_free(repo);
    git_repository_open (&repo, localURL.path.UTF8String);
}



git_repository_config(&cfg, repo);

// connect to repo
error = git_remote_load(&remote, repo, "origin");

error = git_remote_connect(remote, GIT_DIR_FETCH);
// get pack file

git_off_t bytes;
git_indexer_stats stats;
error = git_remote_download(remote, &bytes, &stats);

NSURL *packFolderURL = [localURL URLByAppendingPathComponent:@".git/objects/pack"];
NSFileManager *fileManager = [NSFileManager defaultManager];
NSArray *array = [fileManager contentsOfDirectoryAtURL:packFolderURL includingPropertiesForKeys:nil options:0 error:nil];
NSLog(@"Dictionary:%@",array);
NSString *result;
for (NSURL *url in array) {
    if ([url.path rangeOfString:@".pack"].location != NSNotFound) {
        result = url.path;
    }
}
const char *packname = [result UTF8String];


// unpack pack file
if (packname != NULL) 
{
    git_indexer *indexer;
    git_indexer_stats stats2;
    int error;
    char hash[GIT_OID_HEXSZ + 1] = {0};

    error = git_indexer_new(&indexer, packname);
    error = git_indexer_run(indexer, &stats2);
    error = git_indexer_write(indexer);

    // Get the packfile's hash (which should become it's filename)
    git_oid_fmt(hash, git_indexer_hash(indexer));

    NSString *hashStr = [NSString stringWithCString:hash encoding:NSUTF8StringEncoding];
    hashStr = [NSString stringWithFormat:@"pack-%@.idx",hashStr];
    const char *indexPath = [hashStr UTF8String];

    puts(hash);
    git_index *index;
    git_index_open(&index, indexPath);
    git_index_read(index);
    git_repository_set_index(repo, index);


    git_indexer_free(indexer);
    git_remote_update_tips(remote, update_cb2); //No idea what it does, but it seems like it's important… It does make the branches appear in .git/refs/remotes/origin

}
//Somehow do git checkout master here
return [GTRepository repositoryWithURL:localURL error:nil];

}

解决方案
Since the libgit2 doesn't explicitly mention git clone in its issue list, one lead to follow is in the sources of the original git project with:


builtin/clone.c
contrib/examples/git-clone.sh


That last script will guide you through all the stages of a git clone.

                        
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