1 // file      : examples/cxx/tree/multiroot/driver.cxx
2 // copyright : not copyrighted - public domain
3 
4 #include <memory>   // std::auto_ptr
5 #include <string>
6 #include <fstream>
7 #include <iostream>
8 
9 #include <xercesc/dom/DOM.hpp>
10 #include <xercesc/util/PlatformUtils.hpp>
11 
12 #include <xsd/cxx/xml/string.hxx>       // xml::transcode
13 
14 #include "dom-parse.hxx"
15 
16 #include "protocol.hxx"
17 
18 using namespace std;
19 using namespace protocol;
20 
21 // Parse an XML document and return a pointer to request_t which can
22 // then be tested with dynamic_cast. If your vocabulary does not have
23 // a common base type for all root element types then you can use
24 // xml_schema::type which is a base for all generated types.
25 //
26 auto_ptr<request_t>
parse(istream & is,const string & id)27 parse (istream& is, const string& id)
28 {
29   using namespace xercesc;
30   namespace xml = xsd::cxx::xml;
31 
32   // Parse an XML instance to a DOM document using the parse()
33   // function from dom-parse.hxx.
34   //
35   xml_schema::dom::auto_ptr<DOMDocument> doc (parse (is, id, true));
36 
37   DOMElement* root (doc->getDocumentElement ());
38 
39   string ns (xml::transcode<char> (root->getNamespaceURI ()));
40   string name (xml::transcode<char> (root->getLocalName ()));
41 
42   auto_ptr<request_t> r;
43 
44   // We could have handled the result directly in this function
45   // instead of returning it as an opaque pointer and using
46   // dynamic_cast later to figure out which request we are dealing
47   // with.
48   //
49   if (ns == "http://www.codesynthesis.com/protocol")
50   {
51     if (name == "balance")
52     {
53       // Use the balance parsing function.
54       //
55       r.reset (balance (*doc).release ());
56     }
57     else if (name == "withdraw")
58     {
59       // Use the withdraw parsing function.
60       //
61       r.reset (withdraw (*doc).release ());
62     }
63   }
64 
65   if (r.get () == 0)
66     cerr << "ignoring unknown request: " << ns << "#" << name << endl;
67 
68   return r;
69 }
70 
71 int
main(int argc,char * argv[])72 main (int argc, char* argv[])
73 {
74   if (argc != 2)
75   {
76     cerr << "usage: " << argv[0] << " request.xml" << endl;
77     return 1;
78   }
79 
80   int r (0);
81 
82   // We need to initialize the Xerces-C++ runtime because we
83   // are doing the XML-to-DOM parsing ourselves.
84   //
85   xercesc::XMLPlatformUtils::Initialize ();
86 
87   try
88   {
89     ifstream ifs;
90     ifs.exceptions (ifstream::badbit | ifstream::failbit);
91     ifs.open (argv[1]);
92 
93     auto_ptr<request_t> r (parse (ifs, argv[1]));
94 
95     // Let's print what we've got.
96     //
97     if (balance_t* b = dynamic_cast<balance_t*> (r.get ()))
98     {
99       cerr << "balance request for acc# " << b->account () << endl;
100     }
101     else if (withdraw_t* w = dynamic_cast<withdraw_t*> (r.get ()))
102     {
103       cerr << "withdrawal request for acc# " << w->account () << ", "
104            << "amount: " << w->amount () << endl;
105     }
106     else
107     {
108       cerr << "unknown request" << endl;
109     }
110   }
111   catch (const xml_schema::exception& e)
112   {
113     cerr << e << endl;
114     r = 1;
115   }
116   catch (const std::ios_base::failure&)
117   {
118     cerr << argv[1] << ": unable to open or read failure" << endl;
119     r = 1;
120   }
121 
122   xercesc::XMLPlatformUtils::Terminate ();
123   return r;
124 }
125