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// Copyright 2015 The Weave Authors. All rights reserved.
// Use of this source code is governed by a BSD-style license that can be
// found in the LICENSE file.
#ifndef LIBWEAVE_SRC_NOTIFICATION_XML_NODE_H_
#define LIBWEAVE_SRC_NOTIFICATION_XML_NODE_H_
#include <map>
#include <memory>
#include <string>
#include <vector>
#include <base/macros.h>
namespace weave {
class XmlNodeTest;
class XmppStreamParser;
// XmlNode is a very simple class to represent the XML document element tree.
// It is used in conjunction with expat XML parser to implement XmppStreamParser
// class used to parse Xmpp data stream into individual stanzas.
class XmlNode final {
public:
XmlNode(const std::string& name,
std::map<std::string, std::string> attributes);
// The node's name. E.g. in <foo bar="baz">quux</foo> this will return "foo".
const std::string& name() const;
// The node text content. E.g. in <foo bar="baz">quux</foo> this will return
// "quux".
const std::string& text() const;
// The node attribute map. E.g. in <foo bar="baz">quux</foo> this will return
// {{"bar", "baz"}}.
const std::map<std::string, std::string>& attributes() const;
// Returns the list of child nodes, if any.
const std::vector<std::unique_ptr<XmlNode>>& children() const;
// Retrieves the value of the given attribute specified by |name|.
// If the attribute doesn't exist, returns false and |value| is not modified.
bool GetAttribute(const std::string& name, std::string* value) const;
// Returns the value of the given attribute specified by |name|.
// Returns empty string if the attribute does not exist. This method should be
// used only in limited scopes such as unit tests.
std::string GetAttributeOrEmpty(const std::string& name) const;
// Finds a first occurrence of a child node specified by |name_path|. A name
// path is a "/"-separated list of node names to look for. If |recursive| is
// set to true, the children are recursively traversed trying to match the
// node names. Otherwise only first-level children of the current node are
// matched against the top-level name of |name_path|.
// This method returns a pointer to the first node that matches the path,
// otherwise a nullptr is returned.
const XmlNode* FindFirstChild(const std::string& name_path,
bool recursive) const;
// Finds all the child nodes matching the |name_path|. This returns the list
// of pointers to the child nodes matching the criteria. If |recursive| is
// set to true, the children are recursively traversed trying to match the
// node names. Otherwise only first-level children of the current node are
// matched against the top-level name of |name_path|.
// For example, if the current node represents the <top> element of the
// following XML document:
// <top>
// <node1 id="1"><node2 id="2"><node3 id="3"/></node2></node1>
// <node2 id="4"><node3 id="5"/></node2>
// <node3 id="6"/>
// <node2 id="7"><node4 id="8"><node3 id="9"/></node4></node2>
// </top>
// Then recursively searching for nodes will produce the following results
// (only the node "id" attributes are listed in the results, for brevity):
// FindChildren("node2/node3", false) -> {"5"}.
// FindChildren("node2/node3", true) -> {"3", "5"}.
// FindChildren("node3", false) -> {"6"}.
// FindChildren("node3", true) -> {"3", "5", "6", "9"}.
std::vector<const XmlNode*> FindChildren(const std::string& name_path,
bool recursive) const;
// Adds a new child to the bottom of the child list of this node.
void AddChild(std::unique_ptr<XmlNode> child);
// Converts the node tree to XML-like string. Note that this not necessarily
// produces a valid XML string. It does not use any character escaping or
// canonicalization, which will produce invalid XML if any of the node or
// attribute names or values contain special characters such as ", <, >, etc.
// This function should be used only for logging/debugging purposes only and
// never to generate valid XML from the parsed node tree.
std::string ToString() const;
private:
friend class XmlNodeTest;
friend class XmppStreamParser;
// Sets the node's text. Used by XML parser.
void SetText(const std::string& text);
// Appends the |text| to the node's text string.
void AppendText(const std::string& text);
// Helper method used by FindFirstChild() and FindChildren(). Searches for
// child node(s) matching |name_path|.
// If |children| is not specified (nullptr), this function find the first
// matching node and returns it via return value of the function. If no match
// is found, this function will return nullptr.
// If |children| parameter is not nullptr, found nodes are added to the
// vector pointed to by |children| and search continues until the whole tree
// is inspected. In this mode, the function always returns nullptr.
const XmlNode* FindChildHelper(const std::string& name_path,
bool recursive,
std::vector<const XmlNode*>* children) const;
const XmlNode* parent_{nullptr}; // Weak pointer to the parent node, if any.
std::string name_;
std::string text_;
std::map<std::string, std::string> attributes_;
std::vector<std::unique_ptr<XmlNode>> children_;
DISALLOW_COPY_AND_ASSIGN(XmlNode);
};
} // namespace weave
#endif // LIBWEAVE_SRC_NOTIFICATION_XML_NODE_H_