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vendor/github.com/jesseduffield/go-git/v5/utils/merkletrie/noder/noder.go

@@ -0,0 +1,59 @@
+// Package noder provide an interface for defining nodes in a
+// merkletrie, their hashes and their paths (a noders and its
+// ancestors).
+//
+// The hasher interface is easy to implement naively by elements that
+// already have a hash, like git blobs and trees.  More sophisticated
+// implementations can implement the Equal function in exotic ways
+// though: for instance, comparing the modification time of directories
+// in a filesystem.
+package noder
+
+import "fmt"
+
+// Hasher interface is implemented by types that can tell you
+// their hash.
+type Hasher interface {
+	Hash() []byte
+}
+
+// Equal functions take two hashers and return if they are equal.
+//
+// These functions are expected to be faster than reflect.Equal or
+// reflect.DeepEqual because they can compare just the hash of the
+// objects, instead of their contents, so they are expected to be O(1).
+type Equal func(a, b Hasher) bool
+
+// The Noder interface is implemented by the elements of a Merkle Trie.
+//
+// There are two types of elements in a Merkle Trie:
+//
+// - file-like nodes: they cannot have children.
+//
+// - directory-like nodes: they can have 0 or more children and their
+// hash is calculated by combining their children hashes.
+type Noder interface {
+	Hasher
+	fmt.Stringer // for testing purposes
+	// Name returns the name of an element (relative, not its full
+	// path).
+	Name() string
+	// IsDir returns true if the element is a directory-like node or
+	// false if it is a file-like node.
+	IsDir() bool
+	// Children returns the children of the element.  Note that empty
+	// directory-like noders and file-like noders will both return
+	// NoChildren.
+	Children() ([]Noder, error)
+	// NumChildren returns the number of children this element has.
+	//
+	// This method is an optimization: the number of children is easily
+	// calculated as the length of the value returned by the Children
+	// method (above); yet, some implementations will be able to
+	// implement NumChildren in O(1) while Children is usually more
+	// complex.
+	NumChildren() (int, error)
+}
+
+// NoChildren represents the children of a noder without children.
+var NoChildren = []Noder{}

vendor/github.com/jesseduffield/go-git/v5/utils/merkletrie/noder/path.go

@@ -0,0 +1,90 @@
+package noder
+
+import (
+	"bytes"
+	"strings"
+)
+
+// Path values represent a noder and its ancestors.  The root goes first
+// and the actual final noder the path is referring to will be the last.
+//
+// A path implements the Noder interface, redirecting all the interface
+// calls to its final noder.
+//
+// Paths build from an empty Noder slice are not valid paths and should
+// not be used.
+type Path []Noder
+
+// String returns the full path of the final noder as a string, using
+// "/" as the separator.
+func (p Path) String() string {
+	var buf bytes.Buffer
+	sep := ""
+	for _, e := range p {
+		_, _ = buf.WriteString(sep)
+		sep = "/"
+		_, _ = buf.WriteString(e.Name())
+	}
+
+	return buf.String()
+}
+
+// Last returns the final noder in the path.
+func (p Path) Last() Noder {
+	return p[len(p)-1]
+}
+
+// Hash returns the hash of the final noder of the path.
+func (p Path) Hash() []byte {
+	return p.Last().Hash()
+}
+
+// Name returns the name of the final noder of the path.
+func (p Path) Name() string {
+	return p.Last().Name()
+}
+
+// IsDir returns if the final noder of the path is a directory-like
+// noder.
+func (p Path) IsDir() bool {
+	return p.Last().IsDir()
+}
+
+// Children returns the children of the final noder in the path.
+func (p Path) Children() ([]Noder, error) {
+	return p.Last().Children()
+}
+
+// NumChildren returns the number of children the final noder of the
+// path has.
+func (p Path) NumChildren() (int, error) {
+	return p.Last().NumChildren()
+}
+
+// Compare returns -1, 0 or 1 if the path p is smaller, equal or bigger
+// than other, in "directory order"; for example:
+//
+// "a" < "b"
+// "a/b/c/d/z" < "b"
+// "a/b/a" > "a/b"
+func (p Path) Compare(other Path) int {
+	i := 0
+	for {
+		switch {
+		case len(other) == len(p) && i == len(p):
+			return 0
+		case i == len(other):
+			return 1
+		case i == len(p):
+			return -1
+		default:
+			// We do *not* normalize Unicode here. CGit doesn't.
+			// https://github.com/src-d/go-git/issues/1057
+			cmp := strings.Compare(p[i].Name(), other[i].Name())
+			if cmp != 0 {
+				return cmp
+			}
+		}
+		i++
+	}
+}