[wallet] Specify the policy branch with a map

src/cli.rs

@@ -1,3 +1,4 @@
+use std::collections::BTreeMap;
 use std::str::FromStr;
 
 use clap::{App, Arg, ArgMatches, SubCommand};
@@ -110,7 +111,7 @@ pub fn make_cli_subcommands<'a, 'b>() -> App<'a, 'b> {
                     Arg::with_name("policy")
                         .long("policy")
                         .value_name("POLICY")
-                        .help("Selects which policy will be used to satisfy the descriptor")
+                        .help("Selects which policy should be used to satisfy the descriptor")
                         .takes_value(true)
                         .number_of_values(1),
                 ),
@@ -252,9 +253,9 @@ where
         let unspendable = sub_matches
             .values_of("unspendable")
             .map(|s| s.map(|i| parse_outpoint(i).unwrap()).collect());
-        let policy: Option<Vec<_>> = sub_matches
+        let policy: Option<_> = sub_matches
             .value_of("policy")
-            .map(|s| serde_json::from_str::<Vec<Vec<usize>>>(&s).unwrap());
+            .map(|s| serde_json::from_str::<BTreeMap<String, Vec<usize>>>(&s).unwrap());
 
         let result = wallet.create_tx(
             addressees,

src/descriptor/policy.rs

@@ -14,6 +14,7 @@ use miniscript::{Descriptor, Miniscript, Terminal};
 #[allow(unused_imports)]
 use log::{debug, error, info, trace};
 
+use super::checksum::get_checksum;
 use super::error::Error;
 use crate::descriptor::{Key, MiniscriptExtractPolicy};
 use crate::psbt::PSBTSatisfier;
@@ -93,6 +94,11 @@ impl SatisfiableItem {
             _ => true,
         }
     }
+
+    pub fn id(&self) -> String {
+        get_checksum(&serde_json::to_string(self).expect("Failed to serialize a SatisfiableItem"))
+            .expect("Failed to compute a SatisfiableItem id")
+    }
 }
 
 fn combinations(vec: &Vec<usize>, size: usize) -> Vec<Vec<usize>> {
@@ -328,6 +334,8 @@ impl From<bool> for Satisfaction {
 
 #[derive(Debug, Clone, Serialize)]
 pub struct Policy {
+    id: String,
+
     #[serde(flatten)]
     item: SatisfiableItem,
     satisfaction: Satisfaction,
@@ -376,8 +384,8 @@ impl Condition {
 
 #[derive(Debug)]
 pub enum PolicyError {
-    NotEnoughItemsSelected(usize),
-    TooManyItemsSelected(usize),
+    NotEnoughItemsSelected(String),
+    TooManyItemsSelected(String),
     IndexOutOfRange(usize),
     AddOnLeaf,
     AddOnPartialComplete,
@@ -388,6 +396,7 @@ pub enum PolicyError {
 impl Policy {
     pub fn new(item: SatisfiableItem) -> Self {
         Policy {
+            id: item.id(),
             item,
             satisfaction: Satisfaction::None,
             contribution: Satisfaction::None,
@@ -479,17 +488,12 @@ impl Policy {
     }
 
     pub fn requires_path(&self) -> bool {
-        self.get_requirements(&vec![]).is_err()
+        self.get_requirements(&BTreeMap::new()).is_err()
     }
 
-    pub fn get_requirements(&self, path: &Vec<Vec<usize>>) -> Result<Condition, PolicyError> {
-        self.recursive_get_requirements(path, 0)
-    }
-
-    fn recursive_get_requirements(
+    pub fn get_requirements(
         &self,
-        path: &Vec<Vec<usize>>,
-        index: usize,
+        path: &BTreeMap<String, Vec<usize>>,
     ) -> Result<Condition, PolicyError> {
         // if items.len() == threshold, selected can be omitted and we take all of them by default
         let default = match &self.item {
@@ -498,7 +502,7 @@ impl Policy {
             }
             _ => vec![],
         };
-        let selected = match path.get(index) {
+        let selected = match path.get(&self.id) {
             _ if !default.is_empty() => &default,
             Some(arr) => arr,
             _ => &default,
@@ -508,7 +512,7 @@ impl Policy {
             SatisfiableItem::Thresh { items, threshold } => {
                 let mapped_req = items
                     .iter()
-                    .map(|i| i.recursive_get_requirements(path, index + 1))
+                    .map(|i| i.get_requirements(path))
                     .collect::<Result<Vec<_>, _>>()?;
 
                 // if all the requirements are null we don't care about `selected` because there
@@ -521,7 +525,9 @@ impl Policy {
                 // an empty value for this step in case of n-of-n, because `selected` is set to all
                 // the elements above
                 if selected.len() < *threshold {
-                    return Err(PolicyError::NotEnoughItemsSelected(index));
+                    return Err(PolicyError::NotEnoughItemsSelected(self.id.clone()));
+                } else if selected.len() > *threshold {
+                    return Err(PolicyError::TooManyItemsSelected(self.id.clone()));
                 }
 
                 // check the selected items, see if there are conflicting requirements
@@ -536,7 +542,7 @@ impl Policy {
 
                 Ok(requirements)
             }
-            _ if !selected.is_empty() => Err(PolicyError::TooManyItemsSelected(index)),
+            _ if !selected.is_empty() => Err(PolicyError::TooManyItemsSelected(self.id.clone())),
             SatisfiableItem::AbsoluteTimelock { value } => Ok(Condition {
                 csv: None,
                 timelock: Some(*value),

src/wallet/mod.rs

@@ -126,7 +126,7 @@ where
         addressees: Vec<(Address, u64)>,
         send_all: bool,
         fee_perkb: f32,
-        policy_path: Option<Vec<Vec<usize>>>,
+        policy_path: Option<BTreeMap<String, Vec<usize>>>,
         utxos: Option<Vec<OutPoint>>,
         unspendable: Option<Vec<OutPoint>>,
     ) -> Result<(PSBT, TransactionDetails), Error> {
@@ -134,7 +134,7 @@ where
         if policy.requires_path() && policy_path.is_none() {
             return Err(Error::SpendingPolicyRequired);
         }
-        let requirements = policy.get_requirements(&policy_path.unwrap_or(vec![]))?;
+        let requirements = policy.get_requirements(&policy_path.unwrap_or(BTreeMap::new()))?;
         debug!("requirements: {:?}", requirements);
 
         let mut tx = Transaction {