Class: BSV::Transaction::TransactionInput

Inherits:
Object
  • Object
show all
Defined in:
lib/bsv/transaction/transaction_input.rb

Overview

A transaction input referencing a previous output to spend.

Inputs identify the output being spent by its transaction ID and output index (the "outpoint"), and provide an unlocking script to satisfy the locking script conditions.

Instance Attribute Summary collapse

Class Method Summary collapse

Instance Method Summary collapse

Constructor Details

#initialize(prev_wtxid:, prev_tx_out_index:, unlocking_script: nil, sequence: 0xFFFFFFFF) ⇒ TransactionInput

Returns a new instance of TransactionInput.

Parameters:

  • prev_wtxid (String) —

    32-byte wire-order transaction ID

  • prev_tx_out_index (Integer) —

    output index in the previous transaction

  • unlocking_script (Script::Script, nil) (defaults to: nil) —

    unlocking script (nil if unsigned)

  • sequence (Integer) (defaults to: 0xFFFFFFFF) —

    sequence number



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# File 'lib/bsv/transaction/transaction_input.rb', line 62

def initialize(prev_wtxid:, prev_tx_out_index:, unlocking_script: nil, sequence: 0xFFFFFFFF)
  BSV::Primitives::Hex.validate_wtxid!(prev_wtxid, name: 'prev_wtxid')
  # Defensively copy + freeze so external mutation of the caller's String
  # cannot stale the cached outpoint_binary / to_binary.
  @prev_wtxid = prev_wtxid.b.dup.freeze
  @prev_tx_out_index = prev_tx_out_index
  @unlocking_script = unlocking_script
  @sequence = sequence
  @owning_tx = nil
  BSV.logger&.debug { "[TransactionInput] prev_wtxid set: #{dtxid_hex}:#{@prev_tx_out_index}" }
end

Instance Attribute Details

#prev_tx_out_index ⇒ Integer (readonly)

Returns index of the output within the previous transaction.

Returns:

  • (Integer) —

    index of the output within the previous transaction



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# File 'lib/bsv/transaction/transaction_input.rb', line 15

def prev_tx_out_index
  @prev_tx_out_index
end

#prev_wtxid ⇒ String (readonly)

Returns 32-byte wire-order transaction ID of the output being spent.

Returns:

  • (String) —

    32-byte wire-order transaction ID of the output being spent



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# File 'lib/bsv/transaction/transaction_input.rb', line 12

def prev_wtxid
  @prev_wtxid
end

#sequence ⇒ Object

Returns the value of attribute sequence.



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# File 'lib/bsv/transaction/transaction_input.rb', line 22

def sequence
  @sequence
end

#source_locking_script ⇒ Script::Script?

Note:

Enters the BIP-143 preimage as scriptCode (step 5) when no subscript override is supplied. Same caveat as #source_satoshis: no current cache layer depends on this field, but a future preimage cache would need a setter override here. See sighash-cache.

Returns locking script of the source output (needed for sighash).

Returns:

  • (Script::Script, nil) —

    locking script of the source output (needed for sighash)



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# File 'lib/bsv/transaction/transaction_input.rb', line 46

def source_locking_script
  @source_locking_script
end

#source_satoshis ⇒ Integer?

Note:

Enters the BIP-143 preimage at step 6 but no current cache layer memoises the per-input preimage, so no invalidator is required. If a future change adds preimage or per-input digest memoisation, add a setter override here that invalidates the relevant cache slice. See sighash-cache.

Returns satoshi value of the source output (needed for sighash).

Returns:

  • (Integer, nil) —

    satoshi value of the source output (needed for sighash)



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# File 'lib/bsv/transaction/transaction_input.rb', line 38

def source_satoshis
  @source_satoshis
end

#source_transaction ⇒ Transaction::Tx?

Note:

Source data is lazily resolved from this Tx during BSV::Transaction::Tx#verify and BSV::Transaction::Tx#sighash_preimage. Mutation of this field after resolution has occurred has no effect on caches because no current cache layer depends on resolved source data.

Returns the full source transaction (for BEEF wiring).

Returns:



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# File 'lib/bsv/transaction/transaction_input.rb', line 53

def source_transaction
  @source_transaction
end

#unlocking_script ⇒ Object

Returns the value of attribute unlocking_script.



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# File 'lib/bsv/transaction/transaction_input.rb', line 30

def unlocking_script
  @unlocking_script
end

#unlocking_script_template ⇒ UnlockingScriptTemplate?

Returns template for deferred signing.

Returns:



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# File 'lib/bsv/transaction/transaction_input.rb', line 56

def unlocking_script_template
  @unlocking_script_template
end

Class Method Details

.from_binary(data, offset = 0) ⇒ Array(TransactionInput, Integer)

Deserialise a transaction input from binary data.

Parameters:

  • data (String) —

    binary data

  • offset (Integer) (defaults to: 0) —

    byte offset to start reading from

Returns:



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# File 'lib/bsv/transaction/transaction_input.rb', line 125

def self.from_binary(data, offset = 0)
  if data.bytesize < offset + 36
    raise ArgumentError,
          "truncated input: need 36 bytes for outpoint at offset #{offset}, got #{data.bytesize - offset}"
  end

  prev_wtxid = data.byteslice(offset, 32)
  prev_tx_out_index = data.byteslice(offset + 32, 4).unpack1('V')
  offset += 36

  script_len, vi_size = VarInt.decode(data, offset)
  offset += vi_size

  if data.bytesize < offset + script_len
    raise ArgumentError,
          "truncated input: need #{script_len} bytes for script at offset #{offset}, got #{data.bytesize - offset}"
  end

  unlocking_script = (BSV::Script::Script.from_binary(data.byteslice(offset, script_len)) if script_len.positive?)
  offset += script_len

  if data.bytesize < offset + 4
    raise ArgumentError,
          "truncated input: need 4 bytes for sequence at offset #{offset}, got #{data.bytesize - offset}"
  end

  sequence = data.byteslice(offset, 4).unpack1('V')

  total = 36 + vi_size + script_len + 4
  input = new(
    prev_wtxid: prev_wtxid,
    prev_tx_out_index: prev_tx_out_index,
    unlocking_script: unlocking_script,
    sequence: sequence
  )
  [input, total]
end

.wtxid_from_hex(hex) ⇒ String

Convert a display-order hex transaction ID to wire-order bytes.

Parameters:

  • hex (String) —

    hex-encoded transaction ID (display order)

Returns:

  • (String) —

    32-byte transaction ID in wire byte order



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# File 'lib/bsv/transaction/transaction_input.rb', line 167

def self.wtxid_from_hex(hex)
  BSV::Primitives::Hex.validate_dtxid_hex!(hex, name: 'wtxid_from_hex input')
  wtxid = [hex].pack('H*').reverse
  BSV.logger&.debug { "[TransactionInput] wtxid_from_hex: #{hex} -> #{wtxid.bytesize}B wire-order" }
  wtxid
end

Instance Method Details

#dtxid_hex ⇒ String

The previous transaction ID in display-order hex.

Returns:

  • (String) —

    hex-encoded transaction ID (display order)



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# File 'lib/bsv/transaction/transaction_input.rb', line 188

def dtxid_hex
  @prev_wtxid.reverse.unpack1('H*')
end

#initialize_copy(other) ⇒ Object

Called by #dup and #clone. Clears the owning-Tx backref so that the cloned input does not belong to any transaction until it is explicitly added via Tx#add_input.



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# File 'lib/bsv/transaction/transaction_input.rb', line 77

def initialize_copy(other)
  super
  @owning_tx = nil
end

#outpoint_binary ⇒ String

Note:

Memoised; see sighash-cache for the invalidation contract.

Serialise the outpoint (prev_wtxid + output index) as binary.

Memoised: outpoint components are attr_reader only so the value is immutable after construction. Returns a frozen binary string.

Returns:

  • (String) —

    36-byte outpoint



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# File 'lib/bsv/transaction/transaction_input.rb', line 181

def outpoint_binary
  @outpoint_binary ||= (@prev_wtxid + [@prev_tx_out_index].pack('V')).freeze
end

#to_binary ⇒ String

Note:

Memoised; see sighash-cache for the invalidation contract.

Serialise the input to its binary wire format.

Returns:

  • (String) —

    binary input (outpoint + varint + script + sequence)



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# File 'lib/bsv/transaction/transaction_input.rb', line 109

def to_binary
  @to_binary ||= begin
    script_bytes = @unlocking_script ? @unlocking_script.to_binary : ''.b
    (@prev_wtxid +
      [@prev_tx_out_index].pack('V') +
      VarInt.encode(script_bytes.bytesize) +
      script_bytes +
      [@sequence].pack('V')).freeze
  end
end