Add Spending Policy API

bdk-ffi/src/bdk.udl

@@ -401,6 +401,9 @@ interface Wallet {
 
   string descriptor_checksum(KeychainKind keychain);
 
+  [Throws=DescriptorError]
+  Policy? policies(KeychainKind keychain);
+
   Balance balance();
 
   [Throws=CannotConnectError]
@@ -441,6 +444,10 @@ interface Wallet {
 
 interface Update {};
 
+interface Policy {
+  string id();
+};
+
 interface TxBuilder {
   constructor();
 
@@ -456,6 +463,8 @@ interface TxBuilder {
 
   TxBuilder add_utxo(OutPoint outpoint);
 
+  TxBuilder policy_path(record<string, sequence<u64>> policy_path, KeychainKind keychain);
+
   TxBuilder change_policy(ChangeSpendPolicy change_policy);
 
   TxBuilder do_not_spend_change();

bdk-ffi/src/lib.rs

@@ -57,6 +57,7 @@ use crate::types::FullScanRequestBuilder;
 use crate::types::FullScanScriptInspector;
 use crate::types::KeychainAndIndex;
 use crate::types::LocalOutput;
+use crate::types::Policy;
 use crate::types::ScriptAmount;
 use crate::types::SentAndReceivedValues;
 use crate::types::SyncRequest;

bdk-ffi/src/tx_builder.rs

@@ -3,6 +3,7 @@ use crate::error::CreateTxError;
 use crate::types::ScriptAmount;
 use crate::wallet::Wallet;
 
+use bdk_wallet::KeychainKind;
 use bitcoin_ffi::{Amount, FeeRate, Script};
 
 use bdk_wallet::bitcoin::amount::Amount as BdkAmount;
@@ -11,6 +12,8 @@ use bdk_wallet::bitcoin::ScriptBuf as BdkScriptBuf;
 use bdk_wallet::bitcoin::{OutPoint, Sequence, Txid};
 use bdk_wallet::ChangeSpendPolicy;
 
+use std::collections::BTreeMap;
+use std::collections::HashMap;
 use std::collections::HashSet;
 use std::str::FromStr;
 use std::sync::Arc;
@@ -21,6 +24,7 @@ pub struct TxBuilder {
     pub(crate) recipients: Vec<(BdkScriptBuf, BdkAmount)>,
     pub(crate) utxos: Vec<OutPoint>,
     pub(crate) unspendable: HashSet<OutPoint>,
+    pub(crate) policy_path: (HashMap<String, Vec<u64>>, KeychainKind),
     pub(crate) change_policy: ChangeSpendPolicy,
     pub(crate) manually_selected_only: bool,
     pub(crate) fee_rate: Option<FeeRate>,
@@ -37,6 +41,7 @@ impl TxBuilder {
             recipients: Vec::new(),
             utxos: Vec::new(),
             unspendable: HashSet::new(),
+            policy_path: (HashMap::new(), KeychainKind::External),
             change_policy: ChangeSpendPolicy::ChangeAllowed,
             manually_selected_only: false,
             fee_rate: None,
@@ -104,6 +109,17 @@ impl TxBuilder {
         })
     }
 
+    pub(crate) fn policy_path(
+        &self,
+        policy_path: HashMap<String, Vec<u64>>,
+        keychain: KeychainKind,
+    ) -> Arc<Self> {
+        Arc::new(TxBuilder {
+            policy_path: (policy_path, keychain),
+            ..self.clone()
+        })
+    }
+
     pub(crate) fn change_policy(&self, change_policy: ChangeSpendPolicy) -> Arc<Self> {
         Arc::new(TxBuilder {
             change_policy,
@@ -177,6 +193,15 @@ impl TxBuilder {
         for (script, amount) in &self.recipients {
             tx_builder.add_recipient(script.clone(), *amount);
         }
+        tx_builder.policy_path(
+            self.policy_path
+                .0
+                .clone()
+                .into_iter()
+                .map(|(key, value)| (key, value.into_iter().map(|x| x as usize).collect()))
+                .collect::<BTreeMap<String, Vec<usize>>>(),
+            self.policy_path.1,
+        );
         tx_builder.change_policy(self.change_policy);
         if !self.utxos.is_empty() {
             tx_builder

bdk-ffi/src/types.rs

@@ -15,12 +15,12 @@ use bdk_wallet::chain::tx_graph::CanonicalTx as BdkCanonicalTx;
 use bdk_wallet::chain::{
     ChainPosition as BdkChainPosition, ConfirmationBlockTime as BdkConfirmationBlockTime,
 };
+use bdk_wallet::descriptor::Policy as BdkPolicy;
 use bdk_wallet::AddressInfo as BdkAddressInfo;
 use bdk_wallet::Balance as BdkBalance;
 use bdk_wallet::KeychainKind;
 use bdk_wallet::LocalOutput as BdkLocalOutput;
 use bdk_wallet::Update as BdkUpdate;
-
 use std::sync::{Arc, Mutex};
 
 #[derive(Debug)]
@@ -237,3 +237,22 @@ pub struct KeychainAndIndex {
     pub keychain: KeychainKind,
     pub index: u32,
 }
+
+/// Descriptor spending policy
+#[derive(Debug, PartialEq, Eq, Clone)]
+pub struct Policy(BdkPolicy);
+impl From<BdkPolicy> for Policy {
+    fn from(value: BdkPolicy) -> Self {
+        Policy(value)
+    }
+}
+impl From<Policy> for BdkPolicy {
+    fn from(value: Policy) -> Self {
+        value.0
+    }
+}
+impl Policy {
+    pub fn id(&self) -> String {
+        self.0.id.clone()
+    }
+}

bdk-ffi/src/wallet.rs

@@ -1,13 +1,13 @@
 use crate::bitcoin::{Psbt, Transaction};
 use crate::descriptor::Descriptor;
 use crate::error::{
-    CalculateFeeError, CannotConnectError, CreateWithPersistError, LoadWithPersistError,
-    SignerError, SqliteError, TxidParseError,
+    CalculateFeeError, CannotConnectError, CreateWithPersistError, DescriptorError,
+    LoadWithPersistError, SignerError, SqliteError, TxidParseError,
 };
 use crate::store::Connection;
 use crate::types::{
     AddressInfo, Balance, CanonicalTx, FullScanRequestBuilder, KeychainAndIndex, LocalOutput,
-    SentAndReceivedValues, SyncRequestBuilder, Update,
+    Policy, SentAndReceivedValues, SyncRequestBuilder, Update,
 };
 
 use bitcoin_ffi::{Amount, FeeRate, OutPoint, Script};
@@ -139,6 +139,13 @@ impl Wallet {
         self.get_wallet().descriptor_checksum(keychain)
     }
 
+    pub fn policies(&self, keychain: KeychainKind) -> Result<Option<Arc<Policy>>, DescriptorError> {
+        self.get_wallet()
+            .policies(keychain)
+            .map_err(DescriptorError::from)
+            .map(|e| e.map(|p| Arc::new(p.into())))
+    }
+
     pub fn network(&self) -> Network {
         self.get_wallet().network()
     }
@@ -154,8 +161,7 @@ impl Wallet {
 
     pub(crate) fn sign(
         &self,
-        psbt: Arc<Psbt>,
-        // sign_options: Option<SignOptions>,
+        psbt: Arc<Psbt>, // sign_options: Option<SignOptions>,
     ) -> Result<bool, SignerError> {
         let mut psbt = psbt.0.lock().unwrap();
         self.get_wallet()