forked from gitea/gitea
137 lines
3.2 KiB
Go
137 lines
3.2 KiB
Go
package object
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import (
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"io"
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"gopkg.in/src-d/go-git.v4/plumbing"
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"gopkg.in/src-d/go-git.v4/plumbing/filemode"
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"gopkg.in/src-d/go-git.v4/utils/merkletrie/noder"
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)
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// A treenoder is a helper type that wraps git trees into merkletrie
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// noders.
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//
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// As a merkletrie noder doesn't understand the concept of modes (e.g.
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// file permissions), the treenoder includes the mode of the git tree in
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// the hash, so changes in the modes will be detected as modifications
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// to the file contents by the merkletrie difftree algorithm. This is
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// consistent with how the "git diff-tree" command works.
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type treeNoder struct {
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parent *Tree // the root node is its own parent
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name string // empty string for the root node
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mode filemode.FileMode
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hash plumbing.Hash
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children []noder.Noder // memoized
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}
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// NewTreeRootNode returns the root node of a Tree
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func NewTreeRootNode(t *Tree) noder.Noder {
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if t == nil {
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return &treeNoder{}
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}
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return &treeNoder{
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parent: t,
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name: "",
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mode: filemode.Dir,
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hash: t.Hash,
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}
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}
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func (t *treeNoder) isRoot() bool {
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return t.name == ""
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}
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func (t *treeNoder) String() string {
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return "treeNoder <" + t.name + ">"
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}
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func (t *treeNoder) Hash() []byte {
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if t.mode == filemode.Deprecated {
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return append(t.hash[:], filemode.Regular.Bytes()...)
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}
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return append(t.hash[:], t.mode.Bytes()...)
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}
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func (t *treeNoder) Name() string {
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return t.name
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}
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func (t *treeNoder) IsDir() bool {
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return t.mode == filemode.Dir
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}
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// Children will return the children of a treenoder as treenoders,
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// building them from the children of the wrapped git tree.
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func (t *treeNoder) Children() ([]noder.Noder, error) {
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if t.mode != filemode.Dir {
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return noder.NoChildren, nil
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}
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// children are memoized for efficiency
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if t.children != nil {
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return t.children, nil
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}
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// the parent of the returned children will be ourself as a tree if
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// we are a not the root treenoder. The root is special as it
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// is is own parent.
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parent := t.parent
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if !t.isRoot() {
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var err error
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if parent, err = t.parent.Tree(t.name); err != nil {
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return nil, err
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}
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}
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return transformChildren(parent)
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}
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// Returns the children of a tree as treenoders.
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// Efficiency is key here.
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func transformChildren(t *Tree) ([]noder.Noder, error) {
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var err error
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var e TreeEntry
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// there will be more tree entries than children in the tree,
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// due to submodules and empty directories, but I think it is still
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// worth it to pre-allocate the whole array now, even if sometimes
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// is bigger than needed.
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ret := make([]noder.Noder, 0, len(t.Entries))
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walker := NewTreeWalker(t, false, nil) // don't recurse
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// don't defer walker.Close() for efficiency reasons.
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for {
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_, e, err = walker.Next()
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if err == io.EOF {
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break
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}
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if err != nil {
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walker.Close()
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return nil, err
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}
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ret = append(ret, &treeNoder{
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parent: t,
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name: e.Name,
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mode: e.Mode,
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hash: e.Hash,
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})
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}
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walker.Close()
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return ret, nil
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}
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// len(t.tree.Entries) != the number of elements walked by treewalker
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// for some reason because of empty directories, submodules, etc, so we
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// have to walk here.
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func (t *treeNoder) NumChildren() (int, error) {
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children, err := t.Children()
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if err != nil {
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return 0, err
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}
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return len(children), nil
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}
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