Refactor to return results by value, add wallet list_unspent and related types

.gitignore

@@ -1,7 +1,6 @@
 target
 build
 Cargo.lock
-*.h
 /bdk-kotlin/local.properties
 .gradle
 wallet_db

README.md

@@ -0,0 +1,18 @@
+
+
+Adding new structs and functions
+
+1. Create C safe Rust structs and related functions using safer-ffi
+
+2. Test generated library and `bdk_ffi.h` file with c language tests in `cc/bdk_ffi_test.c`
+
+3. Use `build.sh` and `test.sh` to build c test program and verify functionality and 
+   memory de-allocation via `valgrind` 
+
+4. Update the kotlin native interface LibJna.kt in the `bdk-kotlin` `jvm` module to match `bdk_ffi.h`
+
+5. Create kotlin wrapper classes and interfaces as needed
+
+6. Add tests to `bdk-kotlin` `test-fixtures` module 
+
+7. Use `build.sh` and `test.sh` to build and test `bdk-kotlin` `jvm` and `android` modules

build.sh

@@ -2,6 +2,7 @@
 set -eo pipefail -o xtrace
 
 # rust
+cargo fmt
 cargo build
 cargo test --features c-headers -- generate_headers
 

src/lib.rs

@@ -3,6 +3,7 @@
 mod blockchain;
 mod database;
 mod error;
+mod types;
 mod wallet;
 
 /// The following test function is necessary for the header generation.

src/types.rs

@@ -0,0 +1,34 @@
+use ::safer_ffi::prelude::*;
+use safer_ffi::char_p::char_p_boxed;
+
+#[derive_ReprC]
+#[repr(C)]
+#[derive(Debug)]
+pub struct FfiResult<T> {
+    pub ok: Option<repr_c::Box<T>>,
+    pub err: Option<repr_c::Box<char_p_boxed>>,
+}
+
+#[derive_ReprC]
+#[repr(C)]
+pub struct FfiResultVec<T> {
+    pub ok: repr_c::Vec<T>,
+    pub err: Option<repr_c::Box<char_p_boxed>>,
+}
+
+#[ffi_export]
+fn free_string_result(string_result: FfiResult<char_p_boxed>) {
+    drop(string_result)
+}
+
+#[ffi_export]
+fn free_void_result(void_result: FfiResult<()>) {
+    drop(void_result)
+}
+
+// TODO do we need this? remove?
+/// Frees a Rust-allocated string
+#[ffi_export]
+fn free_string(string: Option<char_p_boxed>) {
+    drop(string)
+}

src/wallet.rs

@@ -1,82 +1,23 @@
-use crate::blockchain::BlockchainConfig;
-use crate::database::DatabaseConfig;
-use crate::error::get_name;
+use std::convert::TryFrom;
+
 use ::safer_ffi::prelude::*;
 use bdk::bitcoin::network::constants::Network::Testnet;
-use bdk::blockchain::{
-    log_progress, AnyBlockchain, AnyBlockchainConfig, ConfigurableBlockchain,
-    ElectrumBlockchainConfig,
-};
+use bdk::blockchain::{log_progress, AnyBlockchain, AnyBlockchainConfig, ConfigurableBlockchain};
 use bdk::database::{AnyDatabase, AnyDatabaseConfig, ConfigurableDatabase};
 use bdk::wallet::AddressIndex::New;
 use bdk::{Error, Wallet};
 use safer_ffi::boxed::Box;
 use safer_ffi::char_p::{char_p_boxed, char_p_ref};
 
-#[derive_ReprC]
-#[ReprC::opaque]
-pub struct VoidResult {
-    raw: Result<(), Error>,
-}
-
-#[ffi_export]
-fn get_void_err(void_result: &VoidResult) -> Option<char_p_boxed> {
-    void_result
-        .raw
-        .as_ref()
-        .err()
-        .map(|e| char_p_boxed::try_from(get_name(e)).unwrap())
-}
-
-#[ffi_export]
-fn free_void_result(void_result: Option<Box<VoidResult>>) {
-    drop(void_result)
-}
+use crate::blockchain::BlockchainConfig;
+use crate::database::DatabaseConfig;
+use crate::error::get_name;
+use crate::types::{FfiResult, FfiResultVec};
 
 #[derive_ReprC]
 #[ReprC::opaque]
-pub struct StringResult {
-    raw: Result<String, Error>,
-}
-
-#[ffi_export]
-fn get_string_ok(string_result: &StringResult) -> Option<char_p_boxed> {
-    string_result
-        .raw
-        .as_ref()
-        .ok()
-        .map(|s| char_p_boxed::try_from(s.clone()).unwrap())
-}
-
-#[ffi_export]
-fn get_string_err(string_result: &StringResult) -> Option<char_p_boxed> {
-    string_result
-        .raw
-        .as_ref()
-        .err()
-        .map(|e| char_p_boxed::try_from(get_name(e)).unwrap())
-}
-
-#[ffi_export]
-fn free_string_result(string_result: Option<Box<StringResult>>) {
-    drop(string_result)
-}
-
-#[derive_ReprC]
-#[ReprC::opaque]
-pub struct WalletRef<'lt> {
-    raw: &'lt Wallet<AnyBlockchain, AnyDatabase>,
-}
-
-#[ffi_export]
-fn free_wallet_ref(wallet_ref: Option<Box<WalletRef>>) {
-    drop(wallet_ref)
-}
-
-#[derive_ReprC]
-#[ReprC::opaque]
-pub struct WalletResult {
-    raw: Result<Wallet<AnyBlockchain, AnyDatabase>, Error>,
+pub struct OpaqueWallet {
+    raw: Wallet<AnyBlockchain, AnyDatabase>,
 }
 
 #[ffi_export]
@@ -85,13 +26,83 @@ fn new_wallet_result(
     change_descriptor: Option<char_p_ref>,
     blockchain_config: &BlockchainConfig,
     database_config: &DatabaseConfig,
-) -> Box<WalletResult> {
+) -> FfiResult<OpaqueWallet> {
     let descriptor = descriptor.to_string();
     let change_descriptor = change_descriptor.map(|s| s.to_string());
     let bc_config = &blockchain_config.raw;
     let db_config = &database_config.raw;
     let wallet_result = new_wallet(descriptor, change_descriptor, bc_config, db_config);
-    Box::new(WalletResult { raw: wallet_result })
+
+    match wallet_result {
+        Ok(w) => FfiResult {
+            ok: Some(Box::new(OpaqueWallet { raw: w })),
+            err: None,
+        },
+        Err(e) => FfiResult {
+            ok: None,
+            err: Some(Box::new(char_p_boxed::try_from(get_name(&e)).unwrap())),
+        },
+    }
+}
+
+#[ffi_export]
+fn free_wallet_result(wallet_result: FfiResult<OpaqueWallet>) {
+    drop(wallet_result);
+}
+
+#[ffi_export]
+fn free_unspent_result(unspent_result: FfiResultVec<LocalUtxo>) {
+    drop(unspent_result)
+}
+
+#[ffi_export]
+fn sync_wallet(opaque_wallet: &OpaqueWallet) -> FfiResult<()> {
+    let void_result = opaque_wallet.raw.sync(log_progress(), Some(100));
+    match void_result {
+        Ok(v) => FfiResult {
+            ok: Some(Box::new(v)),
+            err: None,
+        },
+        Err(e) => FfiResult {
+            ok: None,
+            err: Some(Box::new(char_p_boxed::try_from(get_name(&e)).unwrap())),
+        },
+    }
+}
+
+#[ffi_export]
+fn new_address(opaque_wallet: &OpaqueWallet) -> FfiResult<char_p_boxed> {
+    let new_address = opaque_wallet.raw.get_address(New);
+    let string_result = new_address.map(|a| a.to_string());
+    match string_result {
+        Ok(a) => FfiResult {
+            ok: Some(Box::new(char_p_boxed::try_from(a).unwrap())),
+            err: None,
+        },
+        Err(e) => FfiResult {
+            ok: None,
+            err: Some(Box::new(char_p_boxed::try_from(get_name(&e)).unwrap())),
+        },
+    }
+}
+
+#[ffi_export]
+fn list_unspent(opaque_wallet: &OpaqueWallet) -> FfiResultVec<LocalUtxo> {
+    let unspent_result = opaque_wallet.raw.list_unspent();
+
+    match unspent_result {
+        Ok(v) => FfiResultVec {
+            ok: {
+                let ve: Vec<LocalUtxo> = v.iter().map(|lu| LocalUtxo::from(lu)).collect();
+                repr_c::Vec::from(ve)
+            },
+            err: None,
+        },
+        Err(e) => FfiResultVec {
+            ok: repr_c::Vec::EMPTY,
+            err: Some(Box::new(char_p_boxed::try_from(get_name(&e)).unwrap())),
+        },
+    }
 }
 
 fn new_wallet(
@@ -111,44 +122,64 @@ fn new_wallet(
     Wallet::new(descriptor, change_descriptor, network, database, client)
 }
 
-#[ffi_export]
-fn get_wallet_err(wallet_result: &WalletResult) -> Option<char_p_boxed> {
-    wallet_result
-        .raw
-        .as_ref()
-        .err()
-        .map(|e| char_p_boxed::try_from(get_name(&e)).unwrap())
+// Non-opaque returned structs
+
+#[derive_ReprC]
+#[repr(C)]
+#[derive(Debug, Clone)]
+pub struct OutPoint {
+    /// The referenced transaction's txid, as hex string
+    pub txid: char_p_boxed,
+    /// The index of the referenced output in its transaction's vout
+    pub vout: u32,
 }
 
-#[ffi_export]
-fn get_wallet_ok<'lt>(wallet_result: &'lt WalletResult) -> Option<Box<WalletRef<'lt>>> {
-    wallet_result
-        .raw
-        .as_ref()
-        .ok()
-        .map(|w| Box::new(WalletRef { raw: w }))
+impl From<&bdk::bitcoin::OutPoint> for OutPoint {
+    fn from(op: &bdk::bitcoin::OutPoint) -> Self {
+        OutPoint {
+            txid: char_p_boxed::try_from(op.txid.to_string()).unwrap(),
+            vout: op.vout,
+        }
+    }
 }
 
-#[ffi_export]
-fn sync_wallet<'lt>(wallet_ref: &'lt WalletRef<'lt>) -> Box<VoidResult> {
-    let void_result = wallet_ref.raw.sync(log_progress(), Some(100));
-    Box::new(VoidResult { raw: void_result })
+#[derive_ReprC]
+#[repr(C)]
+#[derive(Debug, Clone)]
+pub struct TxOut {
+    /// The value of the output, in satoshis
+    pub value: u64,
+    /// The script which must satisfy for the output to be spent, as hex string
+    pub script_pubkey: char_p_boxed,
 }
 
-#[ffi_export]
-fn new_address<'lt>(wallet_ref: &'lt WalletRef<'lt>) -> Box<StringResult> {
-    let new_address = wallet_ref.raw.get_address(New);
-    let string_result = new_address.map(|a| a.to_string());
-    Box::new(StringResult { raw: string_result })
+impl From<&bdk::bitcoin::TxOut> for TxOut {
+    fn from(to: &bdk::bitcoin::TxOut) -> Self {
+        TxOut {
+            value: to.value,
+            script_pubkey: char_p_boxed::try_from(to.script_pubkey.to_string()).unwrap(),
+        }
+    }
 }
 
-#[ffi_export]
-fn free_wallet_result(wallet_result: Option<Box<WalletResult>>) {
-    drop(wallet_result)
+#[derive_ReprC]
+#[repr(C)]
+#[derive(Debug, Clone)]
+pub struct LocalUtxo {
+    /// Reference to a transaction output
+    pub outpoint: OutPoint,
+    /// Transaction output
+    pub txout: TxOut,
+    /// Type of keychain, as short 0 for "external" or 1 for "internal"
+    pub keychain: u16,
 }
 
-/// Frees a Rust-allocated string
-#[ffi_export]
-fn free_string(string: Option<char_p_boxed>) {
-    drop(string)
+impl From<&bdk::LocalUtxo> for LocalUtxo {
+    fn from(lu: &bdk::LocalUtxo) -> Self {
+        LocalUtxo {
+            outpoint: OutPoint::from(&lu.outpoint),
+            txout: TxOut::from(&lu.txout),
+            keychain: lu.keychain as u16,
+        }
+    }
 }

test.sh

@@ -6,9 +6,9 @@ cargo test --features c-headers -- generate_headers
 
 # cc
 export LD_LIBRARY_PATH=`pwd`/target/debug
-#valgrind --leak-check=full --show-leak-kinds=all cc/bdk_ffi_test
-cc/bdk_ffi_test
+valgrind --leak-check=full --show-leak-kinds=all cc/bdk_ffi_test
+#cc/bdk_ffi_test
 
-## bdk-kotlin
+# bdk-kotlin
 (cd bdk-kotlin && gradle test)
 (cd bdk-kotlin && gradle :android:connectedDebugAndroidTest)