Expose accessors for TxIn and TxOut

The fields themselves are already public, so there's not a lot of
value for C users for these, but it avoids having to have this
logic written out by hand in the Java bindings, which is nice.

Author: TheBlueMatt

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

@@ -628,17 +628,39 @@ impl TxIn {
 		}
 	}
 }
-
-#[no_mangle]
-/// Frees the witness and script_sig in a TxIn
-pub extern "C" fn TxIn_free(_res: TxIn) { }
-
 #[no_mangle]
 /// Convenience function for constructing a new TxIn
 pub extern "C" fn TxIn_new(witness: Witness, script_sig: derived::CVec_u8Z, sequence: u32, previous_txid: ThirtyTwoBytes, previous_vout: u32) -> TxIn {
 	TxIn { witness, script_sig, sequence, previous_txid, previous_vout }
 }
-
+#[no_mangle]
+/// Gets the `witness` in the given `TxIn`.
+pub extern "C" fn TxIn_get_witness(txin: &TxIn) -> Witness {
+	txin.witness.clone()
+}
+#[no_mangle]
+/// Gets the `script_sig` in the given `TxIn`.
+pub extern "C" fn TxIn_get_script_sig(txin: &TxIn) -> u8slice {
+	u8slice::from_vec(&txin.script_sig)
+}
+#[no_mangle]
+/// Gets the `sequence` in the given `TxIn`.
+pub extern "C" fn TxIn_get_sequence(txin: &TxIn) -> u32 {
+	txin.sequence
+}
+#[no_mangle]
+/// Gets the previous outpoint txid in the given `TxIn`.
+pub extern "C" fn TxIn_get_previous_txid(txin: &TxIn) -> ThirtyTwoBytes {
+	txin.previous_txid
+}
+#[no_mangle]
+/// Gets the previout outpoint index in the given `TxIn`.
+pub extern "C" fn TxIn_get_previous_vout(txin: &TxIn) -> u32 {
+	txin.previous_vout
+}
+#[no_mangle]
+/// Frees the witness and script_sig in a TxIn
+pub extern "C" fn TxIn_free(_res: TxIn) { }
 
 #[repr(C)]
 #[derive(Clone)]
@@ -672,6 +694,16 @@ pub extern "C" fn TxOut_new(script_pubkey: derived::CVec_u8Z, value: u64) -> TxO
 	TxOut { script_pubkey, value }
 }
 #[no_mangle]
+/// Gets the `script_pubkey` in the given `TxOut`.
+pub extern "C" fn TxOut_get_script_pubkey(txout: &TxOut) -> u8slice {
+	u8slice::from_vec(&txout.script_pubkey)
+}
+#[no_mangle]
+/// Gets the value in the given `TxOut`.
+pub extern "C" fn TxOut_get_value(txout: &TxOut) -> u64 {
+	txout.value
+}
+#[no_mangle]
 /// Frees the data pointed to by script_pubkey.
 pub extern "C" fn TxOut_free(_res: TxOut) { }
 #[no_mangle]