Allow using vendored tinyxml2 for XMLRPC

By default, builds will still not have XMLRPC enabled at all and the
configure flag `--with-xmlrpc-tinyxml2` must be specified. If both
xmlrpc-c and tinyxml2 are specified, xmlrpc-c takes precedence.

Basic benchmarks indicate tinyxml2 is 2x faster for small
requests/responses, and that only increases as response sizes get
larger.

test/rpc/xmlrpc_test.cc

@@ -0,0 +1,83 @@
+#include "config.h"
+#include <string>
+#include <iostream>
+
+#include "command_helpers.h"
+#include "rpc/command_map.h"
+
+#include "xmlrpc_test.h"
+#include "control.h"
+#include "globals.h"
+
+CPPUNIT_TEST_SUITE_REGISTRATION(XmlrpcTest);
+
+torrent::Object xmlprpc_cmd_test_reflect(rpc::target_type t, const torrent::Object& obj) { return obj; }
+
+void initialize_command_dynamic();
+
+#if defined(HAVE_XMLRPC_TINYXML2) && !defined(HAVE_XMLRPC_C)
+void
+XmlrpcTest::setUp() {
+  m_commandItr = m_commands;
+  m_xmlrpc = rpc::XmlRpc();
+  m_xmlrpc.initialize();
+  setlocale(LC_ALL, "");
+  cachedTime = rak::timer::current();
+  control = new Control;
+  if (rpc::commands.find("xmlrpc_reflect") == rpc::commands.end()) {
+    CMD2_ANY("xmlrpc_reflect", &xmlprpc_cmd_test_reflect);
+  }
+}
+
+void
+XmlrpcTest::test_basics() {
+  std::ifstream file; file.open("rpc/xmlrpc_test_data.txt");
+  CPPUNIT_ASSERT(file.good());
+  std::vector<std::string> titles;
+  std::vector<std::string> inputs;
+  std::vector<std::string> outputs;
+  std::string line;
+  int index = 0;
+  // Read file into inputs/outputs
+  while (std::getline(file, line)) {
+    if (line.size() == 0) {
+      continue;
+    }
+    if (line[0] == '#') {
+      titles.push_back(line);
+      continue;
+    }
+    if (index % 2) {
+      outputs.push_back(line);
+    } else {
+      inputs.push_back(line);
+    }
+    index++;
+  }
+
+  // Sanity check the above parser
+  CPPUNIT_ASSERT_MESSAGE("Could not parse test data", inputs.size() > 0 && inputs.size() == outputs.size() && inputs.size() == titles.size());
+  for (int i = 0; i < inputs.size(); i++) {
+    std::cout << titles[i] << "\n";
+    auto output = std::string("");
+    m_xmlrpc.process(inputs[i].c_str(), inputs[i].size(), [&output](const char* c, uint32_t l){ output.append(c, l); return true;});
+    CPPUNIT_ASSERT_EQUAL_MESSAGE(titles[i], std::string(outputs[i]), output);
+  }
+}
+
+void
+XmlrpcTest::test_invalid_utf8() {
+  // Surprisingly, this call doesn't fail. TinyXML-2 technically expects
+  // valid UTF-8, but doesn't check strings, and Object strings are
+  // just a series of bytes so it reflects just fine.
+  std::string input = "<?xml version=\"1.0\"?><methodCall><methodName>xmlrpc_reflect</methodName><params><param><value><string></string></value></param><param><value><string>\xc3\x28</string></value></param></params></methodCall>";
+  std::string expected = "<?xml version=\"1.0\"?><methodReponse><params><param><value><array><value><string>\xc3\x28</string></value></array></value></param></params></methodReponse>";
+  auto output = std::string("");
+  m_xmlrpc.process(input.c_str(), input.size(), [&output](const char* c, uint32_t l){ output.append(c, l); return true;});
+  CPPUNIT_ASSERT_EQUAL(expected, output);
+}
+#else
+void XmlrpcTest::test_invalid_utf8() {}
+void XmlrpcTest::test_basics() {}
+void XmlrpcTest::setUp() {}
+#endif

test/rpc/xmlrpc_test.h

@@ -0,0 +1,28 @@
+#include <cppunit/extensions/HelperMacros.h>
+
+#include "rpc/command_map.h"
+#include "rpc/xmlrpc.h"
+
+class XmlrpcTest : public CppUnit::TestFixture {
+  CPPUNIT_TEST_SUITE(XmlrpcTest);
+  CPPUNIT_TEST(test_basics);
+  CPPUNIT_TEST(test_invalid_utf8);
+  CPPUNIT_TEST_SUITE_END();
+
+public:
+  static const int cmd_size = 256;
+
+  void setUp();
+  void tearDown() {}
+
+  void test_basics();
+  void test_invalid_utf8();
+
+private:
+  rpc::XmlRpc m_xmlrpc;
+  
+  rpc::CommandMap m_map;
+
+  rpc::command_base m_commands[cmd_size];
+  rpc::command_base* m_commandItr;
+};

test/rpc/xmlrpc_test_data.txt

@@ -0,0 +1,55 @@
+# Basic call
+<?xml version="1.0"?><methodCall><methodName>xmlrpc_reflect</methodName><params></params></methodCall>
+<?xml version="1.0"?><methodReponse><params><param><value><array/></value></param></params></methodReponse>
+
+# UTF-8 string
+<?xml version="1.0"?><methodCall><methodName>xmlrpc_reflect</methodName><params><param><value><string></string></value></param><param><value><string>чао</string></value></param></params></methodCall>
+<?xml version="1.0"?><methodReponse><params><param><value><array><value><string>чао</string></value></array></value></param></params></methodReponse>
+
+# emoji string
+<?xml version="1.0"?><methodCall><methodName>xmlrpc_reflect</methodName><params><param><value><string></string></value></param><param><value><string>😊</string></value></param></params></methodCall>
+<?xml version="1.0"?><methodReponse><params><param><value><array><value><string>😊</string></value></array></value></param></params></methodReponse>
+
+# base64 data (which gets returned as a string)
+<?xml version="1.0"?><methodCall><methodName>xmlrpc_reflect</methodName><params><param><value><string></string></value></param><param><value><base64>Zm9vYmFy</base64></value></param></params></methodCall>
+<?xml version="1.0"?><methodReponse><params><param><value><array><value><string>foobar</string></value></array></value></param></params></methodReponse>
+
+# i4 ints
+<?xml version="1.0"?><methodCall><methodName>xmlrpc_reflect</methodName><params><param><value><string></string></value></param><param><value><i4>41</i4></value></param></params></methodCall>
+<?xml version="1.0"?><methodReponse><params><param><value><array><value><i4>41</i4></value></array></value></param></params></methodReponse>
+
+# i8 ints
+<?xml version="1.0"?><methodCall><methodName>xmlrpc_reflect</methodName><params><param><value><string></string></value></param><param><value><i8>2247483647</i8></value></param></params></methodCall>
+<?xml version="1.0"?><methodReponse><params><param><value><array><value><i8>2247483647</i8></value></array></value></param></params></methodReponse>
+
+# negative i8 ints
+<?xml version="1.0"?><methodCall><methodName>xmlrpc_reflect</methodName><params><param><value><string></string></value></param><param><value><i8>-2347483647</i8></value></param></params></methodCall>
+<?xml version="1.0"?><methodReponse><params><param><value><array><value><i8>-2347483647</i8></value></array></value></param></params></methodReponse>
+
+# Empty array
+<?xml version="1.0"?><methodCall><methodName>xmlrpc_reflect</methodName><params><param><value><string></string></value></param><param><value><array><data><value><i8>2247483647</i8></value></data></array></value></param></params></methodCall>
+<?xml version="1.0"?><methodReponse><params><param><value><array><value><array><value><i8>2247483647</i8></value></array></value></array></value></param></params></methodReponse>
+
+# Simple array
+<?xml version="1.0"?><methodCall><methodName>xmlrpc_reflect</methodName><params><param><value><string></string></value></param><param><value><array><data></data></array></value></param></params></methodCall>
+<?xml version="1.0"?><methodReponse><params><param><value><array><value><array/></value></array></value></param></params></methodReponse>
+
+# Empty struct
+<?xml version="1.0"?><methodCall><methodName>xmlrpc_reflect</methodName><params><param><value><string></string></value></param><param><value><struct></struct></value></param></params></methodCall>
+<?xml version="1.0"?><methodReponse><params><param><value><array><value><struct/></value></array></value></param></params></methodReponse>
+
+# Simple struct
+<?xml version="1.0"?><methodCall><methodName>xmlrpc_reflect</methodName><params><param><value><string></string></value></param><param><value><struct><member><name>lowerBound</name><value><i4>18</i4></value></member><member><name>upperBound</name><value><i4>139</i4></value></member></struct></value></param></params></methodCall>
+<?xml version="1.0"?><methodReponse><params><param><value><array><value><struct><member><name>lowerBound</name><value><i4>18</i4></value></member><member><name>upperBound</name><value><i4>139</i4></value></member></struct></value></array></value></param></params></methodReponse>
+
+# Invalid - missing method
+<?xml version="1.0"?><methodCall><methodName>no_such_method</methodName><params><param><value><i4>41</i4></value></param></params></methodCall>
+<?xml version="1.0"?><methodReponse><fault><struct><member><name>faultCode</name><value><int>-506</int></value></member><member><name>faultString</name><value><string>Method 'no_such_method' not defined</string></value></member></struct></fault></methodReponse>
+
+# Invalid - i4 target
+<?xml version="1.0"?><methodCall><methodName>xmlrpc_reflect</methodName><params><param><value><i4>41</i4></value></param></params></methodCall>
+<?xml version="1.0"?><methodReponse><fault><struct><member><name>faultCode</name><value><int>-500</int></value></member><member><name>faultString</name><value><string>invalid parameters: target must be a string</string></value></member></struct></fault></methodReponse>
+
+# Invalid - broken XML
+thodCall><methodName>test_a</methodName><params><param><value><i4>41</i4></value></param></params></method
+<?xml version="1.0"?><methodReponse><fault><struct><member><name>faultCode</name><value><int>-503</int></value></member><member><name>faultString</name><value><string>Error=XML_ERROR_PARSING_ELEMENT ErrorID=6 (0x6) Line number=1: XMLElement name=method</string></value></member></struct></fault></methodReponse>