Transaction Metadata¶

typedef struct cardano_transaction_metadata_t cardano_transaction_metadata_t¶: Represents a map of metadatum_label to metadatum.

cardano_error_t cardano_transaction_metadata_new(cardano_transaction_metadata_t **transaction_metadata)¶

Creates and initializes a new instance of a transaction_metadata.

This function allocates and initializes a new instance of cardano_transaction_metadata_t. It returns an error code to indicate the success or failure of the operation.

Usage Example:

cardano_transaction_metadata_t* transaction_metadata = NULL;

// Attempt to create a new transaction_metadata
cardano_error_t result = cardano_transaction_metadata_new(&transaction_metadata);

if (result == CARDANO_SUCCESS)
{
  // Use the transaction_metadata

  // Once done, ensure to clean up and release the transaction_metadata
  cardano_transaction_metadata_unref(&transaction_metadata);
}

Parameters:¶

cardano_transaction_metadata_t **transaction_metadata¶: [out] A pointer to a pointer to a cardano_transaction_metadata_t object. Upon successful initialization, this will point to a newly created cardano_transaction_metadata_t object. This object represents a “strong reference” to the transaction_metadata, fully initialized and ready for use. The caller is responsible for managing the lifecycle of this object. Specifically, once the transaction_metadata is no longer needed, the caller must release it by calling cardano_transaction_metadata_unref.

Returns:¶

CARDANO_SUCCESS if the transaction_metadata was successfully created, or an appropriate error code indicating the failure reason.

cardano_error_t cardano_transaction_metadata_from_cbor(cardano_cbor_reader_t *reader, cardano_transaction_metadata_t **transaction_metadata)¶

Creates a transaction_metadata from a CBOR reader.

This function parses CBOR data using a provided cardano_cbor_reader_t and constructs a cardano_transaction_metadata_t object. It assumes that the CBOR reader is set up correctly and that the CBOR data corresponds to the structure expected for a transaction_metadata.

Usage Example:

cardano_cbor_reader_t* reader = cardano_cbor_reader_new(cbor_data, data_size);
cardano_transaction_metadata_t* transaction_metadata = NULL;

cardano_error_t result = cardano_transaction_metadata_from_cbor(reader, &transaction_metadata);

if (result == CARDANO_SUCCESS)
{
  // Use the transaction_metadata

  // Once done, ensure to clean up and release the transaction_metadata
  cardano_transaction_metadata_unref(&transaction_metadata);
}
else
{
  const char* error = cardano_cbor_reader_get_last_error(reader);
  printf("Failed to decode transaction_metadata: %s\n", error);
}

cardano_cbor_reader_unref(&reader); // Cleanup the CBOR reader

Note

If the function fails, the last error can be retrieved by calling cardano_cbor_reader_get_last_error with the reader. The caller is responsible for freeing the created cardano_transaction_metadata_t object by calling cardano_transaction_metadata_unref when it is no longer needed.

Parameters:¶

cardano_cbor_reader_t *reader¶: [in] A pointer to an initialized cardano_cbor_reader_t that is ready to read the CBOR-encoded transaction_metadata data.
cardano_transaction_metadata_t **transaction_metadata¶: [out] A pointer to a pointer of cardano_transaction_metadata_t that will be set to the address of the newly created transaction_metadata object upon successful decoding.

Returns:¶

A cardano_error_t value indicating the outcome of the operation. Returns CARDANO_SUCCESS if the transaction_metadata was successfully created, or an appropriate error code if an error occurred.

cardano_error_t cardano_transaction_metadata_to_cbor(const cardano_transaction_metadata_t *transaction_metadata, cardano_cbor_writer_t *writer)¶

Serializes a transaction_metadata into CBOR format using a CBOR writer.

This function serializes the given cardano_transaction_metadata_t object using a cardano_cbor_writer_t.

Usage Example:

cardano_transaction_metadata_t* transaction_metadata = ...;
cardano_cbor_writer_t* writer = cardano_cbor_writer_new();

if (writer)
{
  cardano_error_t result = cardano_transaction_metadata_to_cbor(transaction_metadata, writer);

  if (result == CARDANO_SUCCESS)
  {
    // Use the writer's buffer containing the serialized data
  }
  else
  {
    const char* error_message = cardano_cbor_writer_get_last_error(writer);
    printf("Serialization failed: %s\n", error_message);
  }

  cardano_cbor_writer_unref(&writer);
}

cardano_transaction_metadata_unref(&transaction_metadata);

Parameters:¶

const cardano_transaction_metadata_t *transaction_metadata¶: [in] A constant pointer to the cardano_transaction_metadata_t object that is to be serialized.
cardano_cbor_writer_t *writer¶: [out] A pointer to a cardano_cbor_writer_t where the CBOR serialized data will be written. The writer must already be initialized and ready to accept the data.

Returns:¶

Returns CARDANO_SUCCESS if the serialization is successful. If the transaction_metadata or writer is NULL, returns CARDANO_ERROR_POINTER_IS_NULL.

cardano_error_t cardano_transaction_metadata_to_cip116_json(const cardano_transaction_metadata_t *metadata, cardano_json_writer_t *writer)¶

Serializes transaction metadata to CIP-116 JSON.

This function writes the transaction metadata (a map of metadatum labels to values) as a JSON array of key/value entries using the CIP-116 shape.

Notes:

The key is the metadatum label serialized as a decimal string.
The value is produced by cardano_metadatum_to_cip116_json.
The function writes both the opening [ and closing ] of the array.
The writer must be in a context where a JSON value is valid.

Parameters:¶

const cardano_transaction_metadata_t *metadata¶: [in] A valid pointer to a cardano_transaction_metadata_t instance.
cardano_json_writer_t *writer¶: [in] A valid pointer to a cardano_json_writer_t positioned where a value is expected.

Returns:¶

CARDANO_SUCCESS on success; CARDANO_ERROR_POINTER_IS_NULL if any pointer parameter is NULL; CARDANO_ERROR_ENCODING if an element cannot be retrieved or serialized.

size_t cardano_transaction_metadata_get_length(const cardano_transaction_metadata_t *transaction_metadata)¶

Retrieves the length of the transaction metadata.

This function returns the number of key-value pairs contained in the specified transaction metadata.

Usage Example:

cardano_transaction_metadata_t* transaction_metadata = cardano_transaction_metadata_new();

// Populate the transaction_metadata with key-value pairs

size_t length = cardano_transaction_metadata_get_length(transaction_metadata);
printf("The length of the transaction_metadata is: %zu\n", length);

cardano_transaction_metadata_unref(&transaction_metadata);

Parameters:¶

const cardano_transaction_metadata_t *transaction_metadata¶: [in] A constant pointer to the cardano_transaction_metadata_t object for which the length is to be retrieved.

Returns:¶

The number of key-value pairs in the transaction_metadata. Returns 0 if the transaction_metadata is NULL.

cardano_error_t cardano_transaction_metadata_get(cardano_transaction_metadata_t *transaction_metadata, uint64_t key, cardano_metadatum_t **element)¶

Retrieves the value associated with a given key in the transaction_metadata.

This function retrieves the value associated with the specified key in the provided transaction_metadata. It returns the value through the output parameter element. If the key is not found in the transaction_metadata, the output parameter element will be set to NULL.

Usage Example:

cardano_transaction_metadata_t* transaction_metadata = cardano_transaction_metadata_new();

// Populate the transaction_metadata with key-value pairs

uint64_t key = 0;
cardano_metadatum_t* value = NULL;
cardano_error_t result = cardano_transaction_metadata_get(transaction_metadata, key, &value);

if (result == CARDANO_SUCCESS && value != NULL)
{
  // Use the retrieved value
  // ...
}
else
{
  // Handle error or key not found
}

cardano_metadatum_unref(&value); // Clean up the value resource
cardano_transaction_metadata_unref(&transaction_metadata);

Parameters:¶

cardano_transaction_metadata_t *transaction_metadata¶: [in] A constant pointer to the cardano_transaction_metadata_t object from which the value is to be retrieved.
uint64_t key¶: [in] The key whose associated value is to be retrieved from the transaction_metadata.
cardano_metadatum_t **element¶: [out] A pointer to a variable where the retrieved value will be stored. If the key is found in the transaction_metadata, this variable will be set to the associated value. If the key is not found, this variable will be set to NULL.

Returns:¶

CARDANO_SUCCESS if the value associated with the key was successfully retrieved, or an appropriate error code if the input parameters are invalid or any other error occurs.

cardano_error_t cardano_transaction_metadata_insert(cardano_transaction_metadata_t *transaction_metadata, uint64_t key, cardano_metadatum_t *value)¶

Inserts a key-value pair into the transaction_metadata.

This function inserts the specified key-value pair into the provided transaction_metadata.

Usage Example:

cardano_transaction_metadata_t* transaction_metadata = cardano_transaction_metadata_new();

// Create key and value objects
uint64_t key = 755;
cardano_metadatum_t* value = {...}; // Assume value is properly initialized

// Insert the key-value pair into the transaction_metadata
cardano_error_t result = cardano_transaction_metadata_insert(transaction_metadata, key, value);

if (result != CARDANO_SUCCESS)
{
  // Handle insertion failure
}

// Clean up key and value objects
cardano_metadatum_unref(&value);
cardano_transaction_metadata_unref(&transaction_metadata);

Parameters:¶

cardano_transaction_metadata_t *transaction_metadata¶: [in] A constant pointer to the cardano_transaction_metadata_t object where the key-value pair is to be inserted.
uint64_t key¶: [in] The key to be inserted into the transaction_metadata.
cardano_metadatum_t *value¶: [in] The value to be associated with the key and inserted into the transaction_metadata. The caller is responsible for managing the lifecycle of the value object.

Returns:¶

CARDANO_SUCCESS if the key-value pair was successfully inserted, or an appropriate error code if the input parameters are invalid or any other error occurs.

cardano_error_t cardano_transaction_metadata_get_keys(cardano_transaction_metadata_t *transaction_metadata, cardano_metadatum_label_list_t **keys)¶

Retrieves the keys from the transaction_metadata.

This function retrieves all the keys from the provided transaction_metadata and returns them as a list. The caller is responsible for managing the lifecycle of the returned list by calling cardano_metadatum_label_list_t when it is no longer needed.

Usage Example:

cardano_transaction_metadata_t* transaction_metadata = cardano_transaction_metadata_new();

// Populate the transaction_metadata with key-value pairs

cardano_metadatum_label_list_t* keys = NULL;
cardano_error_t result = cardano_transaction_metadata_get_keys(transaction_metadata, &keys);

if (result == CARDANO_SUCCESS)
{
  // Use the list of keys
  // Keys must also be freed if retrieved from the list

  // Once done, ensure to clean up and release the keys list
  cardano_metadatum_label_list_unref(&keys);
}
else
{
  // Handle error
}

cardano_transaction_metadata_unref(&transaction_metadata);

Parameters:¶

cardano_transaction_metadata_t *transaction_metadata¶: [in] A constant pointer to the cardano_transaction_metadata_t object from which the keys are to be retrieved.
cardano_metadatum_label_list_t **keys¶: [out] A pointer to a variable where the retrieved keys will be stored as a list. If successful, this variable will be set to point to the list of keys. The caller is responsible for managing the lifecycle of this list. It must be released by calling cardano_metadatum_label_list_unref when no longer needed.

Returns:¶

CARDANO_SUCCESS if the keys were successfully retrieved, or an appropriate error code if the input parameters are invalid or any other error occurs.

cardano_error_t cardano_transaction_metadata_get_key_at(const cardano_transaction_metadata_t *transaction_metadata, size_t index, uint64_t *metadatum_label)¶

Retrieves the metadatum label at a specific index from the transaction metadata.

This function retrieves the metadatum label at the specified index from the transaction_metadata.

Usage Example:

cardano_transaction_metadata_t* transaction_metadata = NULL;
uint64_t metadatum_label = 0;
size_t index = 0; // Index of the key hash to retrieve

// Assume transaction_metadata is initialized properly

cardano_error_t result = cardano_transaction_metadata_get_key_at(transaction_metadata, index, &metadatum_label);

if (result == CARDANO_SUCCESS)
{
  // Use the metadatum_label
}
else
{
  // Handle the error
}

Parameters:¶

const cardano_transaction_metadata_t *transaction_metadata¶: [in] Pointer to the transaction_metadata object.
size_t index¶: [in] The index of the metadatum label to retrieve.
uint64_t *metadatum_label¶: [out] The metadatum label as uint64_t.

Returns:¶

cardano_error_t indicating the outcome of the operation. Returns CARDANO_SUCCESS if the metadatum label was successfully retrieved, or an appropriate error code indicating the failure reason.

cardano_error_t cardano_transaction_metadata_get_value_at(const cardano_transaction_metadata_t *transaction_metadata, size_t index, cardano_metadatum_t **metadatum)¶

Retrieves the metadatum at a specific index from the transaction_metadata.

This function retrieves the metadatum at the specified index from the transaction_metadata.

Usage Example:

cardano_transaction_metadata_t* transaction_metadata = NULL;
cardano_metadatum_t* metadatum = 0;
size_t index = 0; // Index of the metadatum to retrieve

// Assume transaction_metadata is initialized properly

cardano_error_t result = cardano_transaction_metadata_get_value_at(transaction_metadata, index, &metadatum);

if (result == CARDANO_SUCCESS)
{
  // Use the metadatum
  cardano_metadatum_unref(&metadatum);
}
else
{
  // Handle the error
}

Parameters:¶

const cardano_transaction_metadata_t *transaction_metadata¶: [in] Pointer to the transaction_metadata object.
size_t index¶: [in] The index of the metadatum to retrieve.
cardano_metadatum_t **metadatum¶: [out] On successful retrieval, this will point to the metadatum at the specified index.

Returns:¶

cardano_error_t indicating the outcome of the operation. Returns CARDANO_SUCCESS if the metadatum was successfully retrieved, or an appropriate error code indicating the failure reason.

cardano_error_t cardano_transaction_metadata_get_key_value_at(const cardano_transaction_metadata_t *transaction_metadata, size_t index, uint64_t *metadatum_label, cardano_metadatum_t **metadatum)¶

Retrieves the metadatum label and metadatum at the specified index.

This function retrieves the metadatum label and metadatum from the metadata at the specified index.

Usage Example:

cardano_transaction_metadata_t* transaction_metadata = NULL;
// Assume transaction_metadata is initialized properly

size_t index = 0;
uint64_t metadatum_label = 0;
cardano_metadatum_t* metadatum = NULL;

cardano_error_t result = cardano_transaction_metadata_get_key_value_at(transaction_metadata, index, &metadatum_label, &metadatum);

if (result == CARDANO_SUCCESS)
{
  if (metadatum != NULL)
  {
    // Use the metadatum label and metadatum
  }
  else
  {
    printf("Key-value pair not set at index %zu.\n", index);
  }
}
else
{
  // Handle error
  printf("Failed to get key-value pair at index %zu.\n", index);
}

// Clean up
cardano_transaction_metadata_unref(&transaction_metadata);
cardano_metadatum_unref(&metadatum);

Parameters:¶

const cardano_transaction_metadata_t *transaction_metadata¶: [in] Pointer to the proposed metadata object.
size_t index¶: [in] The index at which to retrieve the key-value pair.
uint64_t *metadatum_label¶: [out] On successful retrieval, this will point to the metadatum label at the specified index.
cardano_metadatum_t **metadatum¶: [out] On successful retrieval, this will point to the metadatum at the specified index. The caller is responsible for managing the lifecycle of this object and should release it using cardano_metadatum_unref when it is no longer needed.

Returns:¶

cardano_error_t indicating the outcome of the operation. Returns CARDANO_SUCCESS if the key-value pair was successfully retrieved, or an appropriate error code indicating the failure reason.

void cardano_transaction_metadata_unref(cardano_transaction_metadata_t **transaction_metadata)¶

Decrements the reference count of a transaction_metadata object.

This function is responsible for managing the lifecycle of a cardano_transaction_metadata_t object by decreasing its reference count. When the reference count reaches zero, the transaction_metadata is finalized; its associated resources are released, and its memory is deallocated.

Usage Example:

cardano_transaction_metadata_t* transaction_metadata = cardano_transaction_metadata_new();

// Perform operations with the transaction_metadata...

cardano_transaction_metadata_unref(&transaction_metadata);
// At this point, transaction_metadata is NULL and cannot be used.

Note

After calling cardano_transaction_metadata_unref, the pointer to the cardano_transaction_metadata_t object will be set to NULL to prevent its reuse.

Parameters:¶

cardano_transaction_metadata_t **transaction_metadata¶: [inout] A pointer to the pointer of the transaction_metadata object. This double indirection allows the function to set the caller’s pointer to NULL, avoiding dangling pointer issues after the object has been freed.

void cardano_transaction_metadata_ref(cardano_transaction_metadata_t *transaction_metadata)¶

Increases the reference count of the cardano_transaction_metadata_t object.

This function is used to manually increment the reference count of a transaction_metadata object, indicating that another part of the code has taken ownership of it. This ensures the object remains allocated and valid until all owners have released their reference by calling cardano_transaction_metadata_unref.

Usage Example:

// Assuming transaction_metadata is a previously created transaction_metadata object

cardano_transaction_metadata_ref(transaction_metadata);

// Now transaction_metadata can be safely used elsewhere without worrying about premature deallocation

Note

Always ensure that for every call to cardano_transaction_metadata_ref there is a corresponding call to cardano_transaction_metadata_unref to prevent memory leaks.

Parameters:¶

cardano_transaction_metadata_t *transaction_metadata¶: A pointer to the transaction_metadata object whose reference count is to be incremented.

size_t cardano_transaction_metadata_refcount(const cardano_transaction_metadata_t *transaction_metadata)¶

Retrieves the current reference count of the cardano_transaction_metadata_t object.

This function returns the number of active references to a transaction_metadata object. It’s useful for debugging purposes or managing the lifecycle of the object in complex scenarios.

Usage Example:

// Assuming transaction_metadata is a previously created transaction_metadata object

size_t ref_count = cardano_transaction_metadata_refcount(transaction_metadata);

printf("Reference count: %zu\n", ref_count);

Warning

This function does not account for transitive references. A transitive reference occurs when an object holds a reference to another object, rather than directly to the cardano_transaction_metadata_t. As such, the reported count may not fully represent the total number of conceptual references in cases where such transitive relationships exist.

Parameters:¶

const cardano_transaction_metadata_t *transaction_metadata¶: A pointer to the transaction_metadata object whose reference count is queried. The object must not be NULL.

Returns:¶

The number of active references to the specified transaction_metadata object. If the object is properly managed (i.e., every cardano_transaction_metadata_ref call is matched with a cardano_transaction_metadata_unref call), this count should reach zero right before the object is deallocated.

void cardano_transaction_metadata_set_last_error(cardano_transaction_metadata_t *transaction_metadata, const char *message)¶

Sets the last error message for a given transaction_metadata object.

Records an error message in the transaction_metadata’s last_error buffer, overwriting any existing message. This is useful for storing descriptive error information that can be later retrieved. The message is truncated if it exceeds the buffer’s capacity.

Note

The error message is limited to 1023 characters, including the null terminator, due to the fixed size of the last_error buffer.

Parameters:¶

cardano_transaction_metadata_t *transaction_metadata¶: [in] A pointer to the cardano_transaction_metadata_t instance whose last error message is to be set. If NULL, the function does nothing.
const char *message¶: [in] A null-terminated string containing the error message. If NULL, the transaction_metadata’s last_error is set to an empty string, indicating no error.

const char *cardano_transaction_metadata_get_last_error(const cardano_transaction_metadata_t *transaction_metadata)¶

Retrieves the last error message recorded for a specific transaction_metadata.

This function returns a pointer to the null-terminated string containing the last error message set by cardano_transaction_metadata_set_last_error for the given transaction_metadata. If no error message has been set, or if the last_error buffer was explicitly cleared, an empty string is returned, indicating no error.

Note

The returned string points to internal storage within the object and must not be modified by the caller. The string remains valid until the next call to cardano_transaction_metadata_set_last_error for the same transaction_metadata, or until the transaction_metadata is deallocated.

Parameters:¶

const cardano_transaction_metadata_t *transaction_metadata¶: [in] A pointer to the cardano_transaction_metadata_t instance whose last error message is to be retrieved. If the transaction_metadata is NULL, the function returns a generic error message indicating the null transaction_metadata.

Returns:¶

A pointer to a null-terminated string containing the last error message for the specified transaction_metadata. If the transaction_metadata is NULL, “Object is NULL.” is returned to indicate the error.