2018-05-29 12:08:59 -07:00
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//! The `plan` module provides a domain-specific language for payment plans. Users create Budget objects that
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2018-05-25 14:51:41 -07:00
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//! are given to an interpreter. The interpreter listens for `Witness` transactions,
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2018-03-20 14:52:46 -07:00
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//! which it uses to reduce the payment plan. When the plan is reduced to a
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//! `Payment`, the payment is executed.
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2018-03-17 13:42:43 -07:00
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use chrono::prelude::*;
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2018-03-26 21:03:26 -07:00
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use signature::PublicKey;
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2018-03-17 13:42:43 -07:00
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2018-05-22 20:42:04 -07:00
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#[derive(Serialize, Deserialize, Debug, PartialEq, Eq, Clone)]
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2018-03-20 14:31:28 -07:00
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pub enum Witness {
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2018-03-17 13:42:43 -07:00
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Timestamp(DateTime<Utc>),
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Signature(PublicKey),
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}
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2018-03-20 14:31:28 -07:00
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#[derive(Serialize, Deserialize, Debug, PartialEq, Eq, Clone)]
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pub enum Condition {
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2018-03-17 13:42:58 -07:00
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Timestamp(DateTime<Utc>),
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Signature(PublicKey),
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}
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impl Condition {
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2018-03-29 11:20:54 -07:00
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/// Return true if the given Witness satisfies this Condition.
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2018-03-20 15:53:41 -07:00
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pub fn is_satisfied(&self, witness: &Witness) -> bool {
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match (self, witness) {
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2018-03-20 14:25:48 -07:00
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(&Condition::Signature(ref pubkey), &Witness::Signature(ref from)) => pubkey == from,
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(&Condition::Timestamp(ref dt), &Witness::Timestamp(ref last_time)) => dt <= last_time,
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2018-03-17 13:42:58 -07:00
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_ => false,
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}
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}
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}
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2018-03-17 13:42:43 -07:00
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#[derive(Serialize, Deserialize, Debug, PartialEq, Eq, Clone)]
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2018-03-17 13:42:50 -07:00
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pub struct Payment {
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2018-03-19 09:03:41 -07:00
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pub tokens: i64,
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2018-03-17 13:42:43 -07:00
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pub to: PublicKey,
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}
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2018-05-29 12:00:44 -07:00
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pub trait PaymentPlan {
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/// Return Payment if the spending plan requires no additional Witnesses.
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fn final_payment(&self) -> Option<Payment>;
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/// Return true if the plan spends exactly `spendable_tokens`.
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fn verify(&self, spendable_tokens: i64) -> bool;
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/// Apply a witness to the spending plan to see if the plan can be reduced.
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/// If so, modify the plan in-place.
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fn apply_witness(&mut self, witness: &Witness);
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}
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