[Bitcoin/Rust] Add support for creating Ordinal NFT inscriptions (#3297)

* expand comment on MIME data prefix in the construction of ordinal inscription

* add NFT module

* update comment on push_opcode

* add test for NFT inscription

* expand full list of inscription types

* compare NFT inscription test data with expected values

* avoid splitting expected values into individual consts, use slices directly

* fix warnings

* rename new_image to just new

* add tw_build_nft_inscription FFI function

* test tw_build_nft_inscription FFI function

* test protobuf NFT inscriptions

* rename ImageType to MimeType

* rename TW::Rust::tw_build_brc20_inscribe_transfer to TW::Rust::tw_build_brc20_transfer_inscription in Script.cpp

* bitcoin-nft-inscriptions

* add Script::buildNftInscription to CXX files, include correct path to MimeType

* add CXX test for SignNftInscription

* add CXX test SignNftInscriptionReveal

* expand C interfaces with NFT inscription construction

* track TWBitcoinOrdinalsMimeType.h

* add Swift tests for NFT inscription

* track TWOrdMimeType.h

* correctly set payload when reading from file

* compare substrings

* avoid var name reuse

* add nft inscription hex data of image and expected output

* small cleanup

* replace TW::Rust::MimeType with TWOrdMimeType

* pass raw integer to Rust, derived from enum variant

* reverse txId for Swift tests

* trigger CI

* run cargo fmt

* revert Podlock and update rust/coverage.stats

* update wallet-core-kotlin version in kmp

* clear todos

* rename tw_build_nft_inscription to tw_build_ordinal_nft_inscription

* remove Foundation import in Swift tests

* add Ordinal prefix to Nft inscriptions where appropriate, deprecate MimeType enum and use strings directly

* pass mime type as string from C++ to Rust

* rename tw_build_ordinal_nft_inscription to tw_bitcoin_build_nft_inscription, fix CoinType import issue

* update wallet-core-kotlin

* update Pods in samples

* run cargo fmt

* update pods in swift/ and swift/Example

* fix how mime type is passed in swift tests

* pass string directly to Rust functions

* undo pod changes in samples

* run cargo fmt

* embed image content and raw transaction in CPP file directly

* embed image as raw hex in Rust

* add embedded data in CPP files into separate file

include/TrustWalletCore/TWBitcoinScript.h

@@ -203,14 +203,24 @@ struct TWBitcoinScript* _Nonnull TWBitcoinScriptBuildPayToWitnessScriptHash(TWDa
 TW_EXPORT_STATIC_METHOD
 TWData* _Nonnull TWBitcoinScriptBuildBRC20InscribeTransfer(TWString* _Nonnull ticker, TWString* _Nonnull amount, TWData* _Nonnull pubkey);
 
+/// Builds the Ordinals inscripton for NFT construction.
+///
+/// \param mimeType the MIME type of the payload
+/// \param payload the payload to inscribe
+/// \param pubkey Non-null pointer to a pubkey
+/// \note Must be deleted with \TWBitcoinScriptDelete
+/// \return A pointer to the built script
+TW_EXPORT_STATIC_METHOD
+TWData* _Nonnull TWBitcoinScriptBuildOrdinalNftInscription(TWString* _Nonnull mimeType, TWData* _Nonnull payload, TWData* _Nonnull pubkey);
+
 /// Builds a appropriate lock script for the given address..
 ///
 /// \param address Non-null pointer to an address
 /// \param coin coin type
 /// \note Must be deleted with \TWBitcoinScriptDelete
 /// \return A pointer to the built script
 TW_EXPORT_STATIC_METHOD
-struct TWBitcoinScript* _Nonnull TWBitcoinScriptLockScriptForAddress(TWString* _Nonnull address, enum TWCoinType coin);
+struct TWBitcoinScript *_Nonnull TWBitcoinScriptLockScriptForAddress(TWString* _Nonnull address, enum TWCoinType coin);
 
 /// Builds a appropriate lock script for the given address with replay.
 TW_EXPORT_STATIC_METHOD

rust/coverage.stats

@@ -1 +1 @@
-87.8
+86.4

rust/tw_bitcoin/src/ffi/mod.rs

@@ -101,7 +101,7 @@ pub(crate) fn taproot_build_and_sign_transaction(proto: SigningInput) -> Result<
                 script_buf,
             )
             .into(),
-            TrVariant::BRC20TRANSFER => {
+            TrVariant::BRC20TRANSFER | TrVariant::NFTINSCRIPTION => {
                 // We construct the merkle root for the given spending script.
                 let spending_script = ScriptBuf::from_bytes(input.spendingScript.to_vec());
                 let merkle_root = TapNodeHash::from_script(
@@ -155,9 +155,14 @@ pub(crate) fn taproot_build_and_sign_transaction(proto: SigningInput) -> Result<
             TrVariant::P2TRKEYPATH => {
                 TxOutputP2TRKeyPath::new_with_script(satoshis, script_buf).into()
             },
+            // We're keeping those two variants separate for now, we're planning
+            // on writing a new interface as part of a larger task anyway.
             TrVariant::BRC20TRANSFER => {
                 TXOutputP2TRScriptPath::new_with_script(satoshis, script_buf).into()
             },
+            TrVariant::NFTINSCRIPTION => {
+                TXOutputP2TRScriptPath::new_with_script(satoshis, script_buf).into()
+            }
         };
 
         builder = builder.add_output(tx);

rust/tw_bitcoin/src/ffi/scripts.rs

@@ -1,9 +1,11 @@
 use crate::brc20::{BRC20TransferInscription, Ticker};
+use crate::nft::OrdinalNftInscription;
 use crate::{
     Recipient, TXOutputP2TRScriptPath, TxOutputP2PKH, TxOutputP2TRKeyPath, TxOutputP2WPKH,
 };
 use bitcoin::{PublicKey, WPubkeyHash};
 use std::borrow::Cow;
+use std::ffi::{c_char, CStr};
 use tw_memory::ffi::c_byte_array::CByteArray;
 use tw_memory::ffi::c_byte_array_ref::CByteArrayRef;
 use tw_misc::try_or_else;
@@ -98,23 +100,25 @@ pub unsafe extern "C" fn tw_build_p2tr_key_path_script(
 
 #[no_mangle]
 // Builds the Ordinals inscripton for BRC20 transfer.
-pub unsafe extern "C" fn tw_build_brc20_inscribe_transfer(
+pub unsafe extern "C" fn tw_build_brc20_transfer_inscription(
     // The 4-byte ticker.
-    ticker: *const u8,
+    ticker: *const c_char,
     amount: u64,
     satoshis: i64,
     pubkey: *const u8,
     pubkey_len: usize,
 ) -> CByteArray {
     // Convert ticket.
-    let slice = try_or_else!(CByteArrayRef::new(ticker, 4).as_slice(), CByteArray::null);
+    let ticker = match CStr::from_ptr(ticker).to_str() {
+        Ok(input) => input,
+        Err(_) => return CByteArray::null(),
+    };
 
-    if slice.len() != 4 {
+    if ticker.len() != 4 {
         return CByteArray::null();
     }
 
-    let string = try_or_else!(String::from_utf8(slice.to_vec()), CByteArray::null);
-    let ticker = Ticker::new(string).expect("ticker must be 4 bytes");
+    let ticker = Ticker::new(ticker.to_string()).expect("ticker must be 4 bytes");
 
     // Convert Recipient
     let slice = try_or_else!(
@@ -142,3 +146,52 @@ pub unsafe extern "C" fn tw_build_brc20_inscribe_transfer(
 
     CByteArray::from(serialized)
 }
+
+#[no_mangle]
+// Builds the Ordinals inscripton for BRC20 transfer.
+pub unsafe extern "C" fn tw_bitcoin_build_nft_inscription(
+    mime_type: *const c_char,
+    data: *const u8,
+    data_len: usize,
+    satoshis: i64,
+    pubkey: *const u8,
+    pubkey_len: usize,
+) -> CByteArray {
+    // Convert mimeType.
+    let mime_type = match CStr::from_ptr(mime_type).to_str() {
+        Ok(input) => input,
+        Err(_) => return CByteArray::null(),
+    };
+
+    // Convert data to inscribe.
+    let data = try_or_else!(
+        CByteArrayRef::new(data, data_len).as_slice(),
+        CByteArray::null
+    );
+
+    // Convert Recipient.
+    let slice = try_or_else!(
+        CByteArrayRef::new(pubkey, pubkey_len).as_slice(),
+        CByteArray::null
+    );
+
+    let recipient = try_or_else!(Recipient::<PublicKey>::from_slice(slice), CByteArray::null);
+
+    // Inscribe NFT data.
+    let nft = OrdinalNftInscription::new(mime_type.as_bytes(), data, recipient)
+        .expect("Ordinal NFT inscription incorrectly constructed");
+
+    let tx_out = TXOutputP2TRScriptPath::new(satoshis as u64, nft.inscription().recipient());
+    let spending_script = nft.inscription().taproot_program();
+
+    // Prepare and serialize protobuf structure.
+    let proto = TransactionOutput {
+        value: satoshis,
+        script: Cow::from(tx_out.script_pubkey.as_bytes()),
+        spendingScript: Cow::from(spending_script.as_bytes()),
+    };
+
+    let serialized = tw_proto::serialize(&proto).expect("failed to serialized transaction output");
+
+    CByteArray::from(serialized)
+}

rust/tw_bitcoin/src/lib.rs

@@ -4,6 +4,7 @@ pub mod brc20;
 pub mod claim;
 pub mod ffi;
 pub mod input;
+pub mod nft;
 pub mod ordinals;
 pub mod output;
 pub mod recipient;

rust/tw_bitcoin/src/nft.rs

@@ -0,0 +1,25 @@
+use crate::ordinals::OrdinalsInscription;
+use crate::{Recipient, Result};
+use bitcoin::PublicKey;
+
+pub struct OrdinalNftInscription(OrdinalsInscription);
+
+impl OrdinalNftInscription {
+    // Constructs an [Ordinal inscription] with a given MIME type. Common MIME
+    // types are:
+    // * "application/json",
+    // * "application/pdf",
+    // * "image/gif",
+    // * "image/jpeg",
+    // * "image/png",
+    // * "text/plain;charset=utf-8"
+    // * ...
+    //
+    // [Ordinal inscription]: https://docs.ordinals.com/inscriptions.html
+    pub fn new(mime_type: &[u8], data: &[u8], recipient: Recipient<PublicKey>) -> Result<Self> {
+        OrdinalsInscription::new(mime_type, data, recipient).map(OrdinalNftInscription)
+    }
+    pub fn inscription(&self) -> &OrdinalsInscription {
+        &self.0
+    }
+}

rust/tw_bitcoin/src/ordinals.rs

@@ -65,31 +65,38 @@ fn create_envelope(mime: &[u8], data: &[u8], internal_key: PublicKey) -> Result<
     let mut mime_buf = PushBytesBuf::new();
     mime_buf.extend_from_slice(mime).map_err(|_| Error::Todo)?;
 
-    // Create data buffer.
-    let mut data_buf = PushBytesBuf::new();
-    data_buf.extend_from_slice(data).map_err(|_| Error::Todo)?;
-
     // Create an Ordinals Inscription.
-    let script = ScriptBuf::builder()
+    let mut builder = ScriptBuf::builder()
         .push_opcode(OP_FALSE)
         .push_opcode(OP_IF)
         .push_slice(b"ord")
         // Separator.
         .push_opcode(OP_PUSHBYTES_1)
-        // This seems to be necessary for now and indicates the size of the
-        // length indicator. The method `push_slice` prefixes the data with the
-        // length, but does not specify how many bytes that prefix requires.
-        //
-        // TODO: Look up if this could be somehow improved or if the `bitcoin`
-        // crate can/should handle that.
+        // MIME types require this addtional push. It seems that the original
+        // creator inadvertently used `push_slice(&[1])`, which leads to
+        // `<1><1>`, which denotes a length prefix followed by the value. On the
+        // other hand, for the data, `push_slice(&[])` is used, producing `<0>`.
+        // This denotes a length prefix followed by no data, as opposed to
+        // '<1><0>', which would be a reasonable assumption. While this appears
+        // inconsistent, it's the current requirement.
         .push_opcode(OP_PUSHBYTES_1)
+        // MIME type identifying the data
         .push_slice(mime_buf.as_push_bytes())
         // Separator.
-        .push_opcode(OP_PUSHBYTES_0)
-        // The payload itself.
-        .push_slice(data_buf)
-        .push_opcode(OP_ENDIF)
-        .into_script();
+        .push_opcode(OP_PUSHBYTES_0);
+
+    // Push the actual data in chunks.
+    for chunk in data.chunks(520) {
+        // Create data buffer.
+        let mut data_buf = PushBytesBuf::new();
+        data_buf.extend_from_slice(chunk).map_err(|_| Error::Todo)?;
+
+        // Push buffer
+        builder = builder.push_slice(data_buf);
+    }
+
+    // Finalize scripts.
+    let script = builder.push_opcode(OP_ENDIF).into_script();
 
     // Generate the necessary spending information. As mentioned in the
     // documentation of this function at the top, this serves two purposes;

rust/tw_bitcoin/src/tests/brc20_transfer.rs

@@ -31,9 +31,6 @@ pub const COMMIT_TX_RAW: &str = "02000000000101089098890d2653567b9e8df2d1fbe5c3c
 // https://www.blockchain.com/explorer/transactions/btc/7046dc2689a27e143ea2ad1039710885147e9485ab6453fa7e87464aa7dd3eca
 pub const REVEAL_TXID: &str = "797d17d47ae66e598341f9dfdea020b04d4017dcf9cc33f0e51f7a6082171fb1";
 pub const REVEAL_RAW: &str = "02000000000101b11f1782607a1fe5f033ccf9dc17404db020a0dedff94183596ee67ad4177d790000000000ffffffff012202000000000000160014e311b8d6ddff856ce8e9a4e03bc6d4fe5050a83d0340de6fd13e43700f59876d305e5a4a5c41ad7ada10bc5a4e4bdd779eb0060c0a78ebae9c33daf77bb3725172edb5bd12e26f00c08f9263e480d53b93818138ad0b5b0063036f7264010118746578742f706c61696e3b636861727365743d7574662d3800377b2270223a226272632d3230222c226f70223a227472616e73666572222c227469636b223a226f616466222c22616d74223a223230227d6821c00f209b6ada5edb42c77fd2bc64ad650ae38314c8f451f3e36d80bc8e26f132cb00000000";
-pub const REVEAL_RAW_P1: &str = "02000000000101b11f1782607a1fe5f033ccf9dc17404db020a0dedff94183596ee67ad4177d790000000000ffffffff012202000000000000160014e311b8d6ddff856ce8e9a4e03bc6d4fe5050a83d0340";
-pub const REVEAL_RAW_SCHNORR: &str = "de6fd13e43700f59876d305e5a4a5c41ad7ada10bc5a4e4bdd779eb0060c0a78ebae9c33daf77bb3725172edb5bd12e26f00c08f9263e480d53b93818138ad0b";
-pub const REVEAL_RAW_P2: &str = "5b0063036f7264010118746578742f706c61696e3b636861727365743d7574662d3800377b2270223a226272632d3230222c226f70223a227472616e73666572222c227469636b223a226f616466222c22616d74223a223230227d6821c00f209b6ada5edb42c77fd2bc64ad650ae38314c8f451f3e36d80bc8e26f132cb00000000";
 
 // Used for transfering the Inscription ("BRC20 transfer").
 // https://www.blockchain.com/explorer/transactions/btc/3e3576eb02667fac284a5ecfcb25768969680cc4c597784602d0a33ba7c654b7
@@ -129,16 +126,11 @@ fn brc20_transfer() {
     // Encode the signed transaction.
     let hex = hex::encode(&transaction, false);
 
-    assert_eq!(
-        REVEAL_RAW,
-        [REVEAL_RAW_P1, REVEAL_RAW_SCHNORR, REVEAL_RAW_P2].concat()
-    );
-
-    assert_eq!(&hex[..164], REVEAL_RAW_P1);
+    assert_eq!(hex[..164], REVEAL_RAW[..164]);
     // We ignore the 64-byte Schnorr signature, since it uses random data for
     // signing on each construction and is therefore not reproducible.
-    assert_ne!(&hex[164..292], REVEAL_RAW_SCHNORR);
-    assert_eq!(&hex[292..], REVEAL_RAW_P2);
+    assert_ne!(hex[164..292], REVEAL_RAW[164..292]);
+    assert_eq!(hex[292..], REVEAL_RAW[292..]);
 
     // # Actually transfer the "transferable" tokens.
     // Based on Bitcoin transaction: