如何使git2go tree.Walk（）非递归并显示文件夹并从目标文件夹开始？

I have the following code:

branch, err := gR.LookupBranch(branchName, git.BranchLocal)
if err != nil {
    return err
}
defer branch.Free()

commit, err := gR.LookupCommit(branch.Target())
if err != nil {
    return err
}
defer commit.Free()

tree, err := gR.LookupTree(commit.TreeId())
if err != nil {
    return err
}
defer tree.Free()

err = tree.Walk(func(td string, te *git.TreeEntry) int {
    if te.Type == git.ObjectBlob {
        fmt.Println(te.Name)
    }
    return 0
})

This recursively prints out all the files in the repository. For example, if we had the following files in our repo:

test_file.txt
test_file_2.txt
test_folder/test_subfile_1.txt
test_folder/test_subfolder/test_subfile_2.txt

Then it would print:

test_file.txt
test_file2.txt
test_subfile_1.txt
test_subfile_2.txt

Instead, my aim is to print:

test_file.txt
test_file_2.txt
test_folder

But then also be able to choose to start the walk from inside the folder, so be able to print:

test_subfile_1.txt
test_subfolder

How can I achieve this? (The aim is to lazy load a directory structure into a web client i.e. to allow the web client to load contents of folders when the user opens them - also note this is a bare repo)

To avoid entering a given directory, it's enough to return 1 from a function passed to Walk.

You can save seen directories in an array or a channel.

Example:

func echoFilesCollectDirs(repo *git.Repository, tree *git.Tree, ch chan *git.Tree) {
    tree.Walk(func(td string, te *git.TreeEntry) int {
        fmt.Println(te.Name)
        if te.Type == git.ObjectTree {
            t, _ := repo.LookupTree(te.Id)
            go func() { ch <- t }() // send tree into channel to process it later
            return 1
        }
        return 0
    })
}

func main() {
    gR, tree := getRepoAndTree() // returns (*git.Repository, *git.Tree)
    ch := make(chan *git.Tree)
    echoFilesCollectDirs(gR, tree, ch)
    // process next directory in a channel
    // t := <-ch
    // echoFilesCollectDirs(gR, t, ch)
}

Note: to make the code shorter, I've removed error handling and a boilerplate part that gets *git.Repository and root *git.Tree (function getRepoAndTree()).