Add dependencies/vendor (whatsapp)

vendor/go.mau.fi/whatsmeow/binary/node.go

@@ -0,0 +1,83 @@
+// Copyright (c) 2021 Tulir Asokan
+//
+// This Source Code Form is subject to the terms of the Mozilla Public
+// License, v. 2.0. If a copy of the MPL was not distributed with this
+// file, You can obtain one at http://mozilla.org/MPL/2.0/.
+
+// Package binary implements encoding and decoding documents in WhatsApp's binary XML format.
+package binary
+
+// Attrs is a type alias for the attributes of an XML element (Node).
+type Attrs = map[string]interface{}
+
+// Node represents an XML element.
+type Node struct {
+	Tag     string      // The tag of the element.
+	Attrs   Attrs       // The attributes of the element.
+	Content interface{} // The content inside the element. Can be nil, a list of Nodes, or a byte array.
+}
+
+// GetChildren returns the Content of the node as a list of nodes. If the content is not a list of nodes, this returns nil.
+func (n *Node) GetChildren() []Node {
+	if n.Content == nil {
+		return nil
+	}
+	children, ok := n.Content.([]Node)
+	if !ok {
+		return nil
+	}
+	return children
+}
+
+// GetChildrenByTag returns the same list as GetChildren, but filters it by tag first.
+func (n *Node) GetChildrenByTag(tag string) (children []Node) {
+	for _, node := range n.GetChildren() {
+		if node.Tag == tag {
+			children = append(children, node)
+		}
+	}
+	return
+}
+
+// GetOptionalChildByTag finds the first child with the given tag and returns it.
+// Each provided tag will recurse in, so this is useful for getting a specific nested element.
+func (n *Node) GetOptionalChildByTag(tags ...string) (val Node, ok bool) {
+	val = *n
+Outer:
+	for _, tag := range tags {
+		for _, child := range val.GetChildren() {
+			if child.Tag == tag {
+				val = child
+				continue Outer
+			}
+		}
+		// If no matching children are found, return false
+		return
+	}
+	// All iterations of loop found a matching child, return it
+	ok = true
+	return
+}
+
+// GetChildByTag does the same thing as GetOptionalChildByTag, but returns the Node directly without the ok boolean.
+func (n *Node) GetChildByTag(tags ...string) Node {
+	node, _ := n.GetOptionalChildByTag(tags...)
+	return node
+}
+
+// Marshal encodes an XML element (Node) into WhatsApp's binary XML representation.
+func Marshal(n Node) ([]byte, error) {
+	w := newEncoder()
+	w.writeNode(n)
+	return w.getData(), nil
+}
+
+// Unmarshal decodes WhatsApp's binary XML representation into a Node.
+func Unmarshal(data []byte) (*Node, error) {
+	r := newDecoder(data)
+	n, err := r.readNode()
+	if err != nil {
+		return nil, err
+	}
+	return n, nil
+}