Repo created

libs/cppjansson/cppjansson.cpp

@@ -0,0 +1,148 @@
+#include "cppjansson.hpp"
+
+#include <type_traits>
+
+namespace
+{
+template <typename T>
+std::string FromJSONToString(json_t const * root)
+{
+  T result;
+  FromJSON(root, result);
+  // TODO(AB): Is std::to_string faster?
+  return strings::to_string(result);
+}
+}  // namespace
+
+namespace base
+{
+json_t * GetJSONObligatoryField(json_t * root, std::string const & field)
+{
+  return GetJSONObligatoryField(root, field.c_str());
+}
+
+json_t * GetJSONObligatoryField(json_t * root, char const * field)
+{
+  return const_cast<json_t *>(GetJSONObligatoryField(const_cast<json_t const *>(root), field));
+}
+
+json_t const * GetJSONObligatoryField(json_t const * root, std::string const & field)
+{
+  return GetJSONObligatoryField(root, field.c_str());
+}
+
+json_t const * GetJSONObligatoryField(json_t const * root, char const * field)
+{
+  auto * value = base::GetJSONOptionalField(root, field);
+  if (!value)
+    MYTHROW(base::Json::Exception, ("Obligatory field", field, "is absent."));
+  return value;
+}
+
+json_t * GetJSONOptionalField(json_t * root, std::string const & field)
+{
+  return GetJSONOptionalField(root, field.c_str());
+}
+
+json_t * GetJSONOptionalField(json_t * root, char const * field)
+{
+  return const_cast<json_t *>(GetJSONOptionalField(const_cast<json_t const *>(root), field));
+}
+
+json_t const * GetJSONOptionalField(json_t const * root, std::string const & field)
+{
+  return GetJSONOptionalField(root, field.c_str());
+}
+
+json_t const * GetJSONOptionalField(json_t const * root, char const * field)
+{
+  if (!json_is_object(root))
+    MYTHROW(base::Json::Exception, ("Bad json object while parsing", field));
+  return json_object_get(root, field);
+}
+
+bool JSONIsNull(json_t const * root)
+{
+  return json_is_null(root);
+}
+
+std::string DumpToString(JSONPtr const & json, size_t flags)
+{
+  std::string result;
+  size_t size = json_dumpb(json.get(), nullptr, 0, flags);
+  if (size == 0)
+    MYTHROW(base::Json::Exception, ("Zero size JSON while serializing"));
+
+  result.resize(size);
+  if (size != json_dumpb(json.get(), &result.front(), size, flags))
+    MYTHROW(base::Json::Exception, ("Wrong size JSON written while serializing"));
+
+  return result;
+}
+
+JSONPtr LoadFromString(std::string const & str)
+{
+  json_error_t jsonError = {};
+  json_t * result = json_loads(str.c_str(), 0, &jsonError);
+  if (!result)
+    MYTHROW(base::Json::Exception, (jsonError.text));
+  return JSONPtr(result);
+}
+
+}  // namespace base
+
+void FromJSON(json_t const * root, double & result)
+{
+  if (!json_is_number(root))
+    MYTHROW(base::Json::Exception, ("Object must contain a json number."));
+  result = json_number_value(root);
+}
+
+void FromJSON(json_t const * root, bool & result)
+{
+  if (!json_is_true(root) && !json_is_false(root))
+    MYTHROW(base::Json::Exception, ("Object must contain a boolean value."));
+  result = json_is_true(root);
+}
+
+std::string FromJSONToString(json_t const * root)
+{
+  if (json_is_string(root))
+    return FromJSONToString<std::string>(root);
+
+  if (json_is_integer(root))
+    return FromJSONToString<json_int_t>(root);
+
+  if (json_is_real(root))
+    return FromJSONToString<double>(root);
+
+  if (json_is_boolean(root))
+    return FromJSONToString<bool>(root);
+
+  MYTHROW(base::Json::Exception, ("Unexpected json type"));
+}
+
+namespace std
+{
+void FromJSON(json_t const * root, std::string & result)
+{
+  if (!json_is_string(root))
+    MYTHROW(base::Json::Exception, ("The field must contain a json string."));
+  result = json_string_value(root);
+}
+}  // namespace std
+
+namespace strings
+{
+void FromJSON(json_t const * root, UniString & result)
+{
+  std::string s;
+  FromJSON(root, s);
+  result = MakeUniString(s);
+}
+
+base::JSONPtr ToJSON(UniString const & s)
+{
+  return ToJSON(ToUtf8(s));
+}
+}  // namespace strings