// Protocol Buffers - Google's data interchange format
// Copyright 2008 Google Inc.  All rights reserved.
// https://developers.google.com/protocol-buffers/
//
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//
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// in the documentation and/or other materials provided with the
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#include <google/protobuf/util/internal/type_info.h>

#include <map>
#include <set>

#include <google/protobuf/stubs/common.h>
#include <google/protobuf/type.pb.h>
#include <google/protobuf/util/internal/utility.h>
#include <google/protobuf/stubs/stringpiece.h>
#include <google/protobuf/stubs/map_util.h>
#include <google/protobuf/stubs/status.h>
#include <google/protobuf/stubs/statusor.h>

namespace google {
namespace protobuf {
namespace util {
namespace converter {

namespace {
// A TypeInfo that looks up information provided by a TypeResolver.
class TypeInfoForTypeResolver : public TypeInfo {
 public:
  explicit TypeInfoForTypeResolver(TypeResolver* type_resolver)
      : type_resolver_(type_resolver) {}

  virtual ~TypeInfoForTypeResolver() {
    DeleteCachedTypes(&cached_types_);
    DeleteCachedTypes(&cached_enums_);
  }

  virtual util::StatusOr<const google::protobuf::Type*> ResolveTypeUrl(
      StringPiece type_url) const {
    map<StringPiece, StatusOrType>::iterator it = cached_types_.find(type_url);
    if (it != cached_types_.end()) {
      return it->second;
    }
    // Stores the string value so it can be referenced using StringPiece in the
    // cached_types_ map.
    const string& string_type_url =
        *string_storage_.insert(type_url.ToString()).first;
    google::protobuf::scoped_ptr<google::protobuf::Type> type(new google::protobuf::Type());
    util::Status status =
        type_resolver_->ResolveMessageType(string_type_url, type.get());
    StatusOrType result =
        status.ok() ? StatusOrType(type.release()) : StatusOrType(status);
    cached_types_[string_type_url] = result;
    return result;
  }

  virtual const google::protobuf::Type* GetTypeByTypeUrl(
      StringPiece type_url) const {
    StatusOrType result = ResolveTypeUrl(type_url);
    return result.ok() ? result.ValueOrDie() : NULL;
  }

  virtual const google::protobuf::Enum* GetEnumByTypeUrl(
      StringPiece type_url) const {
    map<StringPiece, StatusOrEnum>::iterator it = cached_enums_.find(type_url);
    if (it != cached_enums_.end()) {
      return it->second.ok() ? it->second.ValueOrDie() : NULL;
    }
    // Stores the string value so it can be referenced using StringPiece in the
    // cached_enums_ map.
    const string& string_type_url =
        *string_storage_.insert(type_url.ToString()).first;
    google::protobuf::scoped_ptr<google::protobuf::Enum> enum_type(
        new google::protobuf::Enum());
    util::Status status =
        type_resolver_->ResolveEnumType(string_type_url, enum_type.get());
    StatusOrEnum result =
        status.ok() ? StatusOrEnum(enum_type.release()) : StatusOrEnum(status);
    cached_enums_[string_type_url] = result;
    return result.ok() ? result.ValueOrDie() : NULL;
  }

  virtual const google::protobuf::Field* FindField(
      const google::protobuf::Type* type, StringPiece camel_case_name) const {
    if (indexed_types_.find(type) == indexed_types_.end()) {
      PopulateNameLookupTable(type);
      indexed_types_.insert(type);
    }
    StringPiece name =
        FindWithDefault(camel_case_name_table_, camel_case_name, StringPiece());
    if (name.empty()) {
      // Didn't find a mapping. Use whatever provided.
      name = camel_case_name;
    }
    return FindFieldInTypeOrNull(type, name);
  }

 private:
  typedef util::StatusOr<const google::protobuf::Type*> StatusOrType;
  typedef util::StatusOr<const google::protobuf::Enum*> StatusOrEnum;

  template <typename T>
  static void DeleteCachedTypes(map<StringPiece, T>* cached_types) {
    for (typename map<StringPiece, T>::iterator it = cached_types->begin();
         it != cached_types->end(); ++it) {
      if (it->second.ok()) {
        delete it->second.ValueOrDie();
      }
    }
  }

  void PopulateNameLookupTable(const google::protobuf::Type* type) const {
    for (int i = 0; i < type->fields_size(); ++i) {
      const google::protobuf::Field& field = type->fields(i);
      StringPiece name = field.name();
      StringPiece camel_case_name = field.json_name();
      const StringPiece* existing = InsertOrReturnExisting(
          &camel_case_name_table_, camel_case_name, name);
      if (existing && *existing != name) {
        GOOGLE_LOG(WARNING) << "Field '" << name << "' and '" << *existing
                     << "' map to the same camel case name '" << camel_case_name
                     << "'.";
      }
    }
  }

  TypeResolver* type_resolver_;

  // Stores string values that will be referenced by StringPieces in
  // cached_types_, cached_enums_ and camel_case_name_table_.
  mutable set<string> string_storage_;

  mutable map<StringPiece, StatusOrType> cached_types_;
  mutable map<StringPiece, StatusOrEnum> cached_enums_;

  mutable set<const google::protobuf::Type*> indexed_types_;
  mutable map<StringPiece, StringPiece> camel_case_name_table_;
};
}  // namespace

TypeInfo* TypeInfo::NewTypeInfo(TypeResolver* type_resolver) {
  return new TypeInfoForTypeResolver(type_resolver);
}

}  // namespace converter
}  // namespace util
}  // namespace protobuf
}  // namespace google