feat(wallet): Allow user provided RNG, make rand an optional dependency

.github/workflows/cont_integration.yml

@@ -92,7 +92,7 @@ jobs:
         uses: Swatinem/[email protected]
       - name: Check bdk wallet
         working-directory: ./crates/wallet
-        run: cargo check --target wasm32-unknown-unknown --no-default-features --features miniscript/no-std,bdk_chain/hashbrown,dev-getrandom-wasm
+        run: cargo check --target wasm32-unknown-unknown --no-default-features --features miniscript/no-std,bdk_chain/hashbrown
       - name: Check esplora
         working-directory: ./crates/esplora
         run: cargo check --target wasm32-unknown-unknown --no-default-features --features miniscript/no-std,bdk_chain/hashbrown,async

crates/esplora/src/blocking_ext.rs

@@ -1,6 +1,5 @@
 use std::collections::BTreeSet;
 use std::thread::JoinHandle;
-use std::usize;
 
 use bdk_chain::collections::BTreeMap;
 use bdk_chain::spk_client::{FullScanRequest, FullScanResult, SyncRequest, SyncResult};

crates/wallet/Cargo.toml

@@ -13,39 +13,31 @@ edition = "2021"
 rust-version = "1.63"
 
 [dependencies]
-rand = "^0.8"
+rand_core = { version = "0.6.0" }
 miniscript = { version = "12.0.0", features = ["serde"], default-features = false }
-bitcoin = { version = "0.32.0", features = ["serde", "base64", "rand-std"], default-features = false }
+bitcoin = { version = "0.32.0", features = ["serde", "base64"], default-features = false }
 serde = { version = "^1.0", features = ["derive"] }
 serde_json = { version = "^1.0" }
 bdk_chain = { path = "../chain", version = "0.16.0", features = ["miniscript", "serde"], default-features = false }
 
 # Optional dependencies
 bip39 = { version = "2.0", optional = true }
 
-[target.'cfg(target_arch = "wasm32")'.dependencies]
-getrandom = "0.2"
-js-sys = "0.3"
-
 [features]
 default = ["std"]
-std = ["bitcoin/std", "miniscript/std", "bdk_chain/std"]
+std = ["bitcoin/std", "bitcoin/rand-std", "miniscript/std", "bdk_chain/std"]
 compiler = ["miniscript/compiler"]
 all-keys = ["keys-bip39"]
 keys-bip39 = ["bip39"]
 
-# This feature is used to run `cargo check` in our CI targeting wasm. It's not recommended
-# for libraries to explicitly include the "getrandom/js" feature, so we only do it when
-# necessary for running our CI. See: https://docs.rs/getrandom/0.2.8/getrandom/#webassembly-support
-dev-getrandom-wasm = ["getrandom/js"]
-
 [dev-dependencies]
 lazy_static = "1.4"
 assert_matches = "1.5.0"
 tempfile = "3"
 bdk_sqlite = { path = "../sqlite" }
 bdk_file_store = { path = "../file_store" }
 anyhow = "1"
+rand = "^0.8"
 
 [package.metadata.docs.rs]
 all-features = true

crates/wallet/README.md

@@ -70,30 +70,28 @@ To persist `Wallet` state data use a data store crate that reads and writes [`bd
 ```rust,no_run
 use bdk_wallet::{bitcoin::Network, KeychainKind, wallet::{ChangeSet, Wallet}};
 
-fn main() {
-    // Open or create a new file store for wallet data.
-    let mut db =
-        bdk_file_store::Store::<ChangeSet>::open_or_create_new(b"magic_bytes", "/tmp/my_wallet.db")
-            .expect("create store");
-
-    // Create a wallet with initial wallet data read from the file store.
-    let descriptor = "wpkh(tprv8ZgxMBicQKsPdcAqYBpzAFwU5yxBUo88ggoBqu1qPcHUfSbKK1sKMLmC7EAk438btHQrSdu3jGGQa6PA71nvH5nkDexhLteJqkM4dQmWF9g/84'/1'/0'/0/*)";
-    let change_descriptor = "wpkh(tprv8ZgxMBicQKsPdcAqYBpzAFwU5yxBUo88ggoBqu1qPcHUfSbKK1sKMLmC7EAk438btHQrSdu3jGGQa6PA71nvH5nkDexhLteJqkM4dQmWF9g/84'/1'/0'/1/*)";
-    let changeset = db.aggregate_changesets().expect("changeset loaded");
-    let mut wallet =
-        Wallet::new_or_load(descriptor, change_descriptor, changeset, Network::Testnet)
-            .expect("create or load wallet");
-
-    // Get a new address to receive bitcoin.
-    let receive_address = wallet.reveal_next_address(KeychainKind::External);
-    // Persist staged wallet data changes to the file store.
-    let staged_changeset = wallet.take_staged();
-    if let Some(changeset) = staged_changeset {
-        db.append_changeset(&changeset)
-            .expect("must commit changes to database");
-    }
-    println!("Your new receive address is: {}", receive_address.address);
+// Open or create a new file store for wallet data.
+let mut db =
+    bdk_file_store::Store::<ChangeSet>::open_or_create_new(b"magic_bytes", "/tmp/my_wallet.db")
+        .expect("create store");
+
+// Create a wallet with initial wallet data read from the file store.
+let descriptor = "wpkh(tprv8ZgxMBicQKsPdcAqYBpzAFwU5yxBUo88ggoBqu1qPcHUfSbKK1sKMLmC7EAk438btHQrSdu3jGGQa6PA71nvH5nkDexhLteJqkM4dQmWF9g/84'/1'/0'/0/*)";
+let change_descriptor = "wpkh(tprv8ZgxMBicQKsPdcAqYBpzAFwU5yxBUo88ggoBqu1qPcHUfSbKK1sKMLmC7EAk438btHQrSdu3jGGQa6PA71nvH5nkDexhLteJqkM4dQmWF9g/84'/1'/0'/1/*)";
+let changeset = db.aggregate_changesets().expect("changeset loaded");
+let mut wallet =
+    Wallet::new_or_load(descriptor, change_descriptor, changeset, Network::Testnet)
+        .expect("create or load wallet");
+
+// Get a new address to receive bitcoin.
+let receive_address = wallet.reveal_next_address(KeychainKind::External);
+// Persist staged wallet data changes to the file store.
+let staged_changeset = wallet.take_staged();
+if let Some(changeset) = staged_changeset {
+    db.append_changeset(&changeset)
+        .expect("must commit changes to database");
 }
+println!("Your new receive address is: {}", receive_address.address);
 ```
 
 <!-- ### Sync the balance of a descriptor -->

crates/wallet/src/keys/mod.rs

@@ -20,6 +20,8 @@ use core::marker::PhantomData;
 use core::ops::Deref;
 use core::str::FromStr;
 
+use rand_core::{CryptoRng, RngCore};
+
 use bitcoin::secp256k1::{self, Secp256k1, Signing};
 
 use bitcoin::bip32;
@@ -631,12 +633,23 @@ pub trait GeneratableKey<Ctx: ScriptContext>: Sized {
         entropy: Self::Entropy,
     ) -> Result<GeneratedKey<Self, Ctx>, Self::Error>;
 
-    /// Generate a key given the options with a random entropy
+    /// Generate a key given the options with random entropy.
+    ///
+    /// Uses the thread-local random number generator.
+    #[cfg(feature = "std")]
     fn generate(options: Self::Options) -> Result<GeneratedKey<Self, Ctx>, Self::Error> {
-        use rand::{thread_rng, Rng};
+        Self::generate_with_aux_rand(options, &mut bitcoin::key::rand::thread_rng())
+    }
 
+    /// Generate a key given the options with random entropy.
+    ///
+    /// Uses a provided random number generator (rng).
+    fn generate_with_aux_rand(
+        options: Self::Options,
+        rng: &mut (impl CryptoRng + RngCore),
+    ) -> Result<GeneratedKey<Self, Ctx>, Self::Error> {
         let mut entropy = Self::Entropy::default();
-        thread_rng().fill(entropy.as_mut());
+        rng.fill_bytes(entropy.as_mut());
         Self::generate_with_entropy(options, entropy)
     }
 }
@@ -657,8 +670,20 @@ where
     }
 
     /// Generate a key with the default options and a random entropy
+    ///
+    /// Uses the thread-local random number generator.
+    #[cfg(feature = "std")]
     fn generate_default() -> Result<GeneratedKey<Self, Ctx>, Self::Error> {
-        Self::generate(Default::default())
+        Self::generate_with_aux_rand(Default::default(), &mut bitcoin::key::rand::thread_rng())
+    }
+
+    /// Generate a key with the default options and a random entropy
+    ///
+    /// Uses a provided random number generator (rng).
+    fn generate_default_with_aux_rand(
+        rng: &mut (impl CryptoRng + RngCore),
+    ) -> Result<GeneratedKey<Self, Ctx>, Self::Error> {
+        Self::generate_with_aux_rand(Default::default(), rng)
     }
 }