Don't hardcode ver, update node name, and add tests

src/xmpp/hash_disco.cpp

@@ -0,0 +1,50 @@
+#include <utils/base64.hpp>
+#include <utils/sha1.hpp>
+#include <xmpp/xmpp_component.hpp>
+
+namespace Xmpp {
+const std::string hash_disco_sha1(const Stanza &stanza) {
+  std::string s("");
+  const Stanza *query = stanza.get_child("query", DISCO_INFO_NS);
+  std::vector<const XmlNode *> identities = query->get_children("identity", "");
+
+  std::sort(identities.begin(), identities.end(),
+            [](const XmlNode *a, const XmlNode *b) {
+              const std::string category_a = a->get_tag("category");
+              const std::string category_b = b->get_tag("category");
+              const int category_compare = category_a > category_b;
+              if (category_compare != 0)
+                return category_compare;
+              const std::string type_a = a->get_tag("type");
+              const std::string type_b = b->get_tag("type");
+              const int type_compare = type_a > type_b;
+              return type_compare;
+            });
+
+  for (const XmlNode *identity : identities) {
+    const std::string category = identity->get_tag("category");
+    const std::string type = identity->get_tag("type");
+    const std::string name = identity->get_tag("name");
+    s += category + "/" + type + "/" /* + lang + */ "/" + name + "<";
+  }
+  std::vector<const XmlNode *> features = query->get_children("feature", "");
+
+  std::sort(features.begin(), features.end(),
+            [](const XmlNode *a, const XmlNode *b) {
+              const std::string var_a = a->get_tag("var");
+              const std::string var_b = b->get_tag("var");
+              const int var_compare = var_a > var_b;
+              return var_compare;
+            });
+
+  for (const XmlNode *feature : features) {
+    const std::string var = feature->get_tag("var");
+    s += var + "<";
+  }
+
+  const std::string hashed = sha1(s);
+  const std::string encoded = base64::encode(hashed);
+
+  return encoded;
+}
+} // namespace Xmpp