Map bitcoin::Address via a type rather than a string

...allowing users to build an `Address` safely.

Author: TheBlueMatt

c-bindings-gen/src/types.rs

@@ -1076,7 +1076,7 @@ impl<'a, 'c: 'a> TypeResolver<'a, 'c> {
 			"str" => Some("crate::c_types::Str"),
 			"alloc::string::String"|"String"|"std::path::PathBuf" => Some("crate::c_types::Str"),
 
-			"bitcoin::address::Address"|"bitcoin::Address" => Some("crate::c_types::Str"),
+			"bitcoin::address::Address"|"bitcoin::Address" => Some("crate::c_types::Address"),
 
 			"std::time::Duration"|"core::time::Duration" => Some("u64"),
 			"std::time::SystemTime" => Some("u64"),
@@ -1206,6 +1206,8 @@ impl<'a, 'c: 'a> TypeResolver<'a, 'c> {
 			"core::num::ParseIntError" => Some("u8::from_str_radix(\" a\", 10).unwrap_err() /*"),
 			"core::str::Utf8Error" => Some("core::str::from_utf8(&[0xff]).unwrap_err() /*"),
 
+			"bitcoin::address::Address"|"bitcoin::Address" => Some(""),
+
 			"std::time::Duration"|"core::time::Duration" => Some("core::time::Duration::from_secs("),
 			"std::time::SystemTime" => Some("(::std::time::SystemTime::UNIX_EPOCH + std::time::Duration::from_secs("),
 
@@ -1327,6 +1329,8 @@ impl<'a, 'c: 'a> TypeResolver<'a, 'c> {
 			"core::num::ParseIntError" => Some("*/"),
 			"core::str::Utf8Error" => Some("*/"),
 
+			"bitcoin::address::Address"|"bitcoin::Address" => Some(".into_rust()"),
+
 			"std::time::Duration"|"core::time::Duration" => Some(")"),
 			"std::time::SystemTime" => Some("))"),
 
@@ -1442,7 +1446,8 @@ impl<'a, 'c: 'a> TypeResolver<'a, 'c> {
 			"str" => Some(""),
 			"alloc::string::String"|"String"|"std::path::PathBuf" => Some(""),
 
-			"bitcoin::address::Address"|"bitcoin::Address" => Some("alloc::string::ToString::to_string(&"),
+			"bitcoin::address::Address"|"bitcoin::Address" if is_ref => Some("crate::c_types::Address::from_rust("),
+			"bitcoin::address::Address"|"bitcoin::Address" if !is_ref => Some("crate::c_types::Address::from_rust(&"),
 
 			"std::time::Duration"|"core::time::Duration" => Some(""),
 			"std::time::SystemTime" => Some(""),
@@ -1558,7 +1563,7 @@ impl<'a, 'c: 'a> TypeResolver<'a, 'c> {
 			"alloc::string::String"|"String"|"std::path::PathBuf" if is_ref => Some(".as_str().into()"),
 			"alloc::string::String"|"String"|"std::path::PathBuf" => Some(".into()"),
 
-			"bitcoin::address::Address"|"bitcoin::Address" => Some(").into()"),
+			"bitcoin::address::Address"|"bitcoin::Address" => Some(")"),
 
 			"std::time::Duration"|"core::time::Duration" => Some(".as_secs()"),
 			"std::time::SystemTime" => Some(".duration_since(::std::time::SystemTime::UNIX_EPOCH).expect(\"Times must be post-1970\").as_secs()"),

genbindings.sh

@@ -241,6 +241,9 @@ if [ "$CFLAGS_aarch64_apple_darwin" != "" -a "$HOST_OSX" = "true" ]; then
 fi
 cbindgen -v --config cbindgen.toml -o include/lightning.h >/dev/null 2>&1
 
+echo "struct LDKBitcoinAddress;" >> include/ldk_rust_types.h
+echo "typedef struct LDKBitcoinAddress LDKBitcoinAddress;" >> include/ldk_rust_types.h
+
 # cbindgen is relatively braindead when exporting typedefs -
 # it happily exports all our typedefs for private types, even with the
 # generics we specified in C mode! So we drop all those types manually here.

lightning-c-bindings/src/c_types/mod.rs

@@ -5,7 +5,7 @@ pub mod derived;
 
 use bitcoin::Transaction as BitcoinTransaction;
 use bitcoin::Witness as BitcoinWitness;
-use bitcoin::address;
+use bitcoin::Address as BitcoinAddress;
 use bitcoin::WitnessProgram as BitcoinWitnessProgram;
 use bitcoin::WitnessVersion as BitcoinWitnessVersion;
 use bitcoin::key::TweakedPublicKey as BitcoinTweakedPublicKey;
@@ -22,7 +22,11 @@ use bitcoin::secp256k1::Scalar as SecpScalar;
 use bech32;
 
 use core::convert::TryInto; // Bindings need at least rustc 1.34
+use core::str::FromStr;
+
 use alloc::borrow::ToOwned;
+use alloc::string::ToString;
+
 use core::ffi::c_void;
 
 pub(crate) use bitcoin::io::{self, Cursor, Read};
@@ -149,6 +153,43 @@ pub extern "C" fn WitnessProgram_clone(orig: &WitnessProgram) -> WitnessProgram
 /// Releases any memory held by the given `WitnessProgram` (which is currently none)
 pub extern "C" fn WitnessProgram_free(o: WitnessProgram) { }
 
+#[derive(Clone)]
+#[repr(C)]
+/// Represents a valid Bitcoin on-chain address.
+pub struct Address {
+	address: Box<BitcoinAddress>,
+}
+impl Address {
+	pub(crate) fn into_rust(&self) -> BitcoinAddress {
+		(*self.address).clone()
+	}
+	pub(crate) fn from_rust(address: &BitcoinAddress) -> Self {
+		Self { address: Box::new(address.clone()) }
+	}
+}
+
+#[no_mangle]
+/// Gets the string representation of the address in `addr`
+pub extern "C" fn Address_to_string(addr: &Address) -> Str {
+	addr.address.to_string().into()
+}
+#[no_mangle]
+/// Constructs a new `Address` (option) from the given string representation.
+///
+/// Returns `None` only if the address is invalid.
+pub extern "C" fn Address_new(s: Str) -> derived::COption_AddressZ {
+	match BitcoinAddress::from_str(s.into_str()) {
+		Ok(a) => derived::COption_AddressZ::Some(Address { address: Box::new(a.assume_checked()) }),
+		Err(_) => derived::COption_AddressZ::None,
+	}
+}
+#[no_mangle]
+/// Releases any memory held by the given `Address`
+pub extern "C" fn Address_free(o: Address) { }
+#[no_mangle]
+/// Creates a new Address which has the same data as `orig`
+pub extern "C" fn Address_clone(orig: &Address) -> Address { orig.clone() }
+
 #[derive(Clone)]
 #[repr(C)]
 /// Represents a valid secp256k1 public key serialized in "compressed form" as a 33 byte array.