nix/libutil/xml-writer.cc

   1 #include <assert.h>
   2
   3 #include "xml-writer.hh"
   4
   5
   6 namespace nix {
   7
   8
   9 XMLWriter::XMLWriter(bool indent, std::ostream & output)
  10     : output(output), indent(indent)
  11 {
  12     output << "<?xml version='1.0' encoding='utf-8'?>" << std::endl;
  13     closed = false;
  14 }
  15
  16
  17 XMLWriter::~XMLWriter()
  18 {
  19     close();
  20 }
  21
  22
  23 void XMLWriter::close()
  24 {
  25     if (closed) return;
  26     while (!pendingElems.empty()) closeElement();
  27     closed = true;
  28 }
  29
  30
  31 void XMLWriter::indent_(unsigned int depth)
  32 {
  33     if (!indent) return;
  34     output << string(depth * 2, ' ');
  35 }
  36
  37
  38 void XMLWriter::openElement(const string & name,
  39     const XMLAttrs & attrs)
  40 {
  41     assert(!closed);
  42     indent_(pendingElems.size());
  43     output << "<" << name;
  44     writeAttrs(attrs);
  45     output << ">";
  46     if (indent) output << std::endl;
  47     pendingElems.push_back(name);
  48 }
  49
  50
  51 void XMLWriter::closeElement()
  52 {
  53     assert(!pendingElems.empty());
  54     indent_(pendingElems.size() - 1);
  55     output << "</" << pendingElems.back() << ">";
  56     if (indent) output << std::endl;
  57     pendingElems.pop_back();
  58     if (pendingElems.empty()) closed = true;
  59 }
  60
  61
  62 void XMLWriter::writeEmptyElement(const string & name,
  63     const XMLAttrs & attrs)
  64 {
  65     assert(!closed);
  66     indent_(pendingElems.size());
  67     output << "<" << name;
  68     writeAttrs(attrs);
  69     output << " />";
  70     if (indent) output << std::endl;
  71 }
  72
  73
  74 void XMLWriter::writeAttrs(const XMLAttrs & attrs)
  75 {
  76     for (XMLAttrs::const_iterator i = attrs.begin(); i != attrs.end(); ++i) {
  77         output << " " << i->first << "=\"";
  78         for (unsigned int j = 0; j < i->second.size(); ++j) {
  79             char c = i->second[j];
  80             if (c == '"') output << "&quot;";
  81             else if (c == '<') output << "&lt;";
  82             else if (c == '>') output << "&gt;";
  83             else if (c == '&') output << "&amp;";
  84             /* Escape newlines to prevent attribute normalisation (see
  85                XML spec, section 3.3.3. */
  86             else if (c == '\n') output << "&#xA;";
  87             else output << c;
  88         }
  89         output << "\"";
  90     }
  91 }
  92
  93
  94 }