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