src/common/long_string_dictionary.h

// Copyright (c) 2017, Google Inc.
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#ifndef COMMON_LONG_STRING_DICTIONARY_H_
#define COMMON_LONG_STRING_DICTIONARY_H_

#include <string>

#include "common/simple_string_dictionary.h"

namespace google_breakpad {
// key_size is the maxium size that |key| can take in
// SimpleStringDictionary which is defined in simple_string_dictionary.h.
//
// value_size is the maxium size that |value| can take in
// SimpleStringDictionary which is defined in simple_string_dictionary.h.
//
// LongStringDictionary is a subclass of SimpleStringDictionary which supports
// longer values to be stored in the dictionary. The maximum length supported is
// (value_size - 1) * 10.
//
// For example, LongStringDictionary will store long value with key 'abc' into
// segment values with segment keys 'abc__1', 'abc__2', 'abc__3', ...
//
// Clients must avoid using the same suffixes as their key's suffix when
// LongStringDictionary is used.
class LongStringDictionary : public SimpleStringDictionary {
 public:
  // Stores |value| into |key|, or segment values into segment keys. The maxium
  // number of segments is 10. If |value| can not be stored in 10 segments, it
  // will be truncated. Replacing the existing value if |key| is already present
  // and replacing the existing segment values if segment keys are already
  // present.
  //
  // |key| must not be NULL. If the |value| need to be divided into segments,
  // the lengh of |key| must be smaller enough so that lengths of segment keys
  // which are key with suffixes are all samller than (key_size - 1). Currently,
  // the max length of suffixes are 4.
  //
  // If |value| is NULL, the key and its corresponding segment keys are removed
  // from the map. If there is no more space in the map, then the operation
  // silently fails.
  void SetKeyValue(const char* key, const char* value);

  // Given |key|, removes any associated value or associated segment values.
  // |key| must not be NULL. If the key is not found, searchs its segment keys
  // and removes corresponding segment values if found.
  bool RemoveKey(const char* key);

  // Given |key|, returns its corresponding |value|. |key| must not be NULL. If
  // the key is found, its corresponding |value| is returned.
  //
  // If no corresponding |value| is found, segment keys of the given |key| will
  // be used to search for corresponding segment values. If segment values
  // exist, assembled value from them is returned. If no segment value exists,
  // NULL is returned.
  const std::string GetValueForKey(const char* key) const;
};
} // namespace google_breakpad

#endif // COMMON_LONG_STRING_DICTIONARY_H_