xml_lite.hpp

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#pragma once
//
// A deliberately small XML reader covering exactly the subset the `.fta`
// files use: a single root element, nested elements, double/single quoted
// attributes, self-closing tags, comments, an optional XML declaration, the
// five predefined entities, and ASCII numeric character references.
//
// We do not reuse src/HCL/xmlParser: it is only built when ENABLE_HCL=ON (the
// production macOS and HPC builds set it OFF) and it is LGPL, which the
// open-source packaging would rather not inherit for a new component.
//
// Anything outside the subset (DOCTYPE, CDATA, processing instructions beyond
// the declaration) is rejected with a parse error rather than silently
// mis-parsed. Namespace prefixes are not interpreted: a colon is an ordinary
// name character. Text between elements is skipped.
//
#include <stdexcept>
#include <string>
#include <vector>
 
namespace faulttree::xml {
 
class XmlError : public std::runtime_error {
public:
  explicit XmlError(const std::string &what) : std::runtime_error(what) {}
};
 
struct Attribute {
  std::string name;  
  std::string value; 
};
 
struct Element {
  std::string name;                  
  std::vector<Attribute> attributes; 
  std::vector<Element> children;     
 
  [[nodiscard]] const std::string *attribute(const std::string &name) const;
  [[nodiscard]] std::string attributeOr(const std::string &name,
                                        const std::string &fallback) const;
  [[nodiscard]] const Element *child(const std::string &name) const;
  [[nodiscard]] std::vector<const Element *>
  childrenNamed(const std::string &name) const;
};
 
Element parse(const std::string &text);
 
Element parseFile(const std::string &path);
 
} // namespace faulttree::xml