Struct ConfirmationsPolicy 

pub struct ConfirmationsPolicy { /* private fields */ }

Implementations

impl ConfirmationsPolicy

pub const MIN: Self

A policy to use the minimum number of confirmations possible: 1 confirmation for shielded notes irrespective of origin, and 0 confirmations for spends of transparent UTXOs in wallet-internal shielding transactions.

pub fn new( trusted: NonZeroU32, untrusted: NonZeroU32, allow_zero_conf_shielding: bool, ) -> Result<Self, ConfirmationsPolicyError>

Constructs a new ConfirmationsPolicy with trusted and untrusted fields set to the provided values.

The number of confirmations required for trusted notes must be less than or equal to the number of confirmations required for untrusted notes; this returns an error if this invariant is violated.

WARNING: This should only be used with great care to avoid problems of transaction distinguishability; prefer ConfirmationsPolicy::default() instead.

pub fn new_symmetrical( min_confirmations: NonZeroU32, allow_zero_conf_shielding: bool, ) -> Self

Constructs a new ConfirmationsPolicy with trusted and untrusted fields both set to min_confirmations.

WARNING: This should only be used with great care to avoid problems of transaction distinguishability; prefer ConfirmationsPolicy::default() instead.

pub fn new_unchecked( trusted: u32, untrusted: u32, allow_zero_conf_shielding: bool, ) -> Self

Available on crate features test-dependencies only.

Constructs a new ConfirmationsPolicy with trusted and untrusted fields set to the provided values, which must both be nonzero. The number of trusted confirmations required must be less than or equal to the number of untrusted confirmations required.

Panics

Panics if trusted > untrusted or either argument value is zero.

pub fn new_symmetrical_unchecked( min_confirmations: u32, allow_zero_conf_shielding: bool, ) -> Self

Available on crate features test-dependencies only.

Constructs a new ConfirmationsPolicy with trusted and untrusted fields both set to min_confirmations.

Panics

Panics if min_confirmations == 0

pub fn trusted(&self) -> NonZeroU32

Returns the number of confirmations required before trusted notes may be spent.

See ZIP 315 for details.

pub fn untrusted(&self) -> NonZeroU32

Returns the number of confirmations required before untrusted notes may be spent.

See ZIP 315 for details.

pub fn anchor_height(&self, target_height: TargetHeight) -> BlockHeight

Returns the shielded anchor height to use for a transaction targeting target_height under this policy: target_height less the number of required trusted confirmations.

This is the anchor used to interpret a proposal step that carries no explicit anchor height — a purely transparent step, whose anchor is unused (see crate::proposal::Step::anchor_height).

pub fn bucketed( &self, grid: AnchorGrid, target_height: TargetHeight, activation_height: BlockHeight, ) -> Option<Self>

Returns this policy adjusted so that the shielded anchor for target_height lands on a boundary of grid, or None if no boundary is reachable.

A ZIP 318 pool crossing is proved against a boundary block rather than the chain tip, so that many wallets’ crossings share a small set of anchors instead of each pinning a unique recent block.

Bucketing is expressed as a RAISED CONFIRMATION REQUIREMENT rather than as a separately lowered anchor, because the anchor and the bound on which notes may be spent are the same quantity: target_height less the required confirmations. Moving that one number moves both together, which is what makes it impossible to select a note having no witness at the bucketed anchor. Lowering the anchor on its own would leave two numbers free to drift.

The untrusted requirement is raised to match when it would otherwise fall below the trusted one, preserving this type’s trusted <= untrusted invariant.

The boundary chosen is the one BEFORE the most recent one — an anchor age of 1, the smallest ZIP 318 admits. Anchoring to the most recent boundary would be an age of 0, which no migration transfer uses.

activation_height is the activation of the pool being crossed into; the chosen boundary must lie strictly above it.

Returns None when no usable boundary is reachable: when the ordinary anchor lies below the first boundary after activation_height, or where the required confirmations would reach back past the genesis block. Reporting that as “unable to bucket” is what lets a caller fall back, rather than build a proposal that is bound to fail.

pub fn allow_zero_conf_shielding(&self) -> bool

Available on crate feature transparent-inputs only.

Returns whether or not transparent inputs may be spent with zero confirmations in shielding transactions.

pub fn confirmations_until_spendable( &self, target_height: TargetHeight, pool_type: PoolType, receiving_key_scope: Option<Scope>, mined_height: Option<BlockHeight>, tx_trusted: bool, max_shielding_input_height: Option<BlockHeight>, tx_shielding_inputs_trusted: bool, ) -> u32

Returns the number of confirmations until a transaction output is considered spendable, given information about the output and the inputs to the transaction that produced it.

Parameters

• target_height: The minimum height at which the output will be potentially spent.
• pool_type: The Zcash pool that the output was received into.
• receiving_key_scope: The ZIP 32 [Scope] of the key that received the output, or None if the scope is unknown or corresponds to the ephemeral transparent key scope.
• mined_height: The block height at which the transaction that produced the output was mined, if any.
• tx_trusted: A boolean flag indicating whether the received transaction has been explicitly marked as trusted by the user.
• max_shielding_input_height: For outputs that are the result of wallet-internal shielding transactions, the maximum height at which any transparent input to that transaction was received.
• tx_shielding_inputs_trusted: For outputs that are the result of wallet-internal shielding transactions, a flag indicating whether all transparent inputs to that transaction have been explicitly marked as trusted by the user.

Trait Implementations

impl Clone for ConfirmationsPolicy

fn clone(&self) -> Self

Returns a duplicate of the value.

fn clone_from(&mut self, source: &Self)

Performs copy-assignment from source.

impl Copy for ConfirmationsPolicy

impl Debug for ConfirmationsPolicy

fn fmt(&self, f: &mut Formatter<'_>) -> Result

Formats the value using the given formatter.

impl Default for ConfirmationsPolicy

The default confirmations policy according to ZIP 315.

• Require 3 confirmations for “trusted” transaction outputs (outputs produced by the wallet)
• Require 10 confirmations for “untrusted” outputs (those sent to the wallet by external/third parties)
• Allow zero-conf shielding of transparent UTXOs irrespective of their origin, but treat the resulting shielding transaction’s outputs as though the original transparent UTXOs had instead been received as untrusted shielded outputs.

fn default() -> Self

Returns the “default value” for a type.

impl Eq for ConfirmationsPolicy

impl PartialEq for ConfirmationsPolicy

fn eq(&self, other: &Self) -> bool

Equality operator ==.

fn ne(&self, other: &Rhs) -> bool

Inequality operator !=.

impl StructuralPartialEq for ConfirmationsPolicy