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#ifndef MOZC_DICTIONARY_DICTIONARY_INTERFACE_H_
#define MOZC_DICTIONARY_DICTIONARY_INTERFACE_H_

namespace mozc {

// These structures are defined in converter
struct Node;
class NodeAllocatorInterface;

class DictionaryInterface {
 public:
  // limitation for LookupPrefixWithLimit
  struct Limit {
    int key_len_lower_limit;
    Limit() : key_len_lower_limit(0) {}
  };

  virtual Node *LookupPredictive(const char *str, int size,
                                 NodeAllocatorInterface *allocator) const = 0;

  virtual Node *LookupPrefixWithLimit(
      const char *str, int size,
      const Limit &limit,
      NodeAllocatorInterface *allocator) const = 0;

  Node *LookupPrefix(const char *str, int size,
                     NodeAllocatorInterface *allocator) const {
    Limit limit;
    limit.key_len_lower_limit = 0;  // no limit
    return LookupPrefixWithLimit(str, size, limit, allocator);
  }

  // For reverse lookup, the reading is stored in Node::value and the word
  // is stored in Node::key.
  virtual Node *LookupReverse(const char *str, int size,
                              NodeAllocatorInterface *allocator) const = 0;

  virtual void PopulateReverseLookupCache(
      const char *str, int size, NodeAllocatorInterface *allocator) const {}
  virtual void ClearReverseLookupCache(
      NodeAllocatorInterface *allocator) const {}

  // Sync mutable dictionary data into local disk.
  virtual bool Sync() { return true; }

  // Reload dictionary data from local disk.
  virtual bool Reload() { return true; }

 protected:
  // Do not allow instantiation/destruction
  DictionaryInterface() {}
  virtual ~DictionaryInterface() {}
};

class DictionaryFactory {
 public:
  // return singleton object
  static DictionaryInterface *GetDictionary();

  // dependency injection for unittesting
  static void SetDictionary(DictionaryInterface *dictionary);

 private:
  DictionaryFactory() {}
  ~DictionaryFactory() {}
};
} // namespace mozc

#endif  // MOZC_DICTIONARY_INTERFACE_H_