build: leverage WASM codegen changes to auto-generate Python SWIG code

- Auto generate _wrap* calls for Python.
- Assert that fixed length returns are the expected size where possible.
- Ignore non _alloc init functions automatically.
- Prefer SWIG %ignore directive to header defines.
- Remove support for Python 2.x.
- Fix base58 conversion length; use length override calls first.

Following this change, no manual SWIG changes are needed to add typical
new calls to Python wrappers.

Author: jgriffiths

CHANGES.md

@@ -5,6 +5,11 @@
   wrappers default this to zero for backwards compatibility.
 - bip39_mnemonic_to_seed is no longer available for SWIG-wrapped languages.
   Callers should use bip39_mnemonic_to_seed512 instead.
+- Python: Some calls (e.g. bip39_mnemonic_to_seed512, aes, and aes_cbc) used
+  to take output buffers to fill and return the number of bytes written. These
+  calls now automatically create and fill thier buffer, returning it as the
+  only return value. The number of bytes written can be determined by using
+  len() on the returned output buffer.
 
 ## Version 0.8.6
 - Support for PSET v0 (Elements) has been removed.

README.md

@@ -24,7 +24,7 @@ Wally can currently be built for:
 And can be used from:
 - C and compatible languages which can call C interfaces
 - C++ (see include/wally.hpp for C++ container support)
-- Python 2.7+ or 3.x
+- Python 3.x
 - Java
 - Javascript via node.js or Cordova or WebAssembly/Emscripten compatible
 
@@ -122,7 +122,7 @@ It is suggested you only install this way into a virtualenv while the library
 is under heavy development.
 
 If you wish to explicitly choose the python version to use, set the
-`PYTHON_VERSION` environment variable (to e.g. `2.7`, `3`, `3.7` etc) before
+`PYTHON_VERSION` environment variable (to e.g. `3`, `3.7` etc) before
 running `pip` or (when compiling manually) `./configure`.
 
 You can also install the binary [wally releases](https://github.com/ElementsProject/libwally-core/releases)

include/wally_bip32.h

@@ -92,7 +92,6 @@ WALLY_CORE_API int bip32_key_free(
     const struct ext_key *hdkey);
 #endif /* SWIG_PYTHON */
 
-#ifndef SWIG
 /**
  * Initialize a key.
  */
@@ -111,7 +110,6 @@ WALLY_CORE_API int bip32_key_init(
     const unsigned char *parent160,
     size_t parent160_len,
     struct ext_key *output);
-#endif
 
 /**
  * As per `bip32_key_init`, but allocates the key.
@@ -132,7 +130,6 @@ WALLY_CORE_API int bip32_key_init_alloc(
     size_t parent160_len,
     struct ext_key **output);
 
-#ifndef SWIG
 /**
  * Create a new master extended key from entropy.
  *
@@ -170,7 +167,6 @@ WALLY_CORE_API int bip32_key_from_seed(
     uint32_t version,
     uint32_t flags,
     struct ext_key *output);
-#endif
 
 /**
  * As per `bip32_key_from_seed_custom`, but allocates the key.
@@ -212,7 +208,6 @@ WALLY_CORE_API int bip32_key_serialize(
     size_t len);
 
 
-#ifndef SWIG
 /**
  * Un-serialize an extended key from memory.
  *
@@ -224,7 +219,6 @@ WALLY_CORE_API int bip32_key_unserialize(
     const unsigned char *bytes,
     size_t bytes_len,
     struct ext_key *output);
-#endif
 
 /**
  * As per `bip32_key_unserialize`, but allocates the key.
@@ -236,7 +230,6 @@ WALLY_CORE_API int bip32_key_unserialize_alloc(
     size_t bytes_len,
     struct ext_key **output);
 
-#ifndef SWIG
 /**
  * Create a new child extended key from a parent extended key.
  *
@@ -255,7 +248,6 @@ WALLY_CORE_API int bip32_key_from_parent(
     uint32_t child_num,
     uint32_t flags,
     struct ext_key *output);
-#endif
 
 /**
  * As per `bip32_key_from_parent`, but allocates the key.
@@ -267,7 +259,6 @@ WALLY_CORE_API int bip32_key_from_parent_alloc(
     uint32_t flags,
     struct ext_key **output);
 
-#ifndef SWIG
 /**
  * Create a new child extended key from a parent extended key and a path.
  *
@@ -286,7 +277,6 @@ WALLY_CORE_API int bip32_key_from_parent_path(
     size_t child_path_len,
     uint32_t flags,
     struct ext_key *output);
-#endif
 
 /**
  * As per `bip32_key_from_parent_path`, but allocates the key.
@@ -299,7 +289,6 @@ WALLY_CORE_API int bip32_key_from_parent_path_alloc(
     uint32_t flags,
     struct ext_key **output);
 
-#ifndef SWIG
 /**
  * Create a new child extended key from a parent extended key and a path string.
  *
@@ -331,7 +320,6 @@ WALLY_CORE_API int bip32_key_from_parent_path_str_n(
     uint32_t child_num,
     uint32_t flags,
     struct ext_key *output);
-#endif
 
 /**
  * As per `bip32_key_from_parent_path_str`, but allocates the key.
@@ -357,7 +345,6 @@ WALLY_CORE_API int bip32_key_from_parent_path_str_n_alloc(
     struct ext_key **output);
 
 #ifdef BUILD_ELEMENTS
-#ifndef SWIG
 /**
  * Derive the pub tweak from a parent extended key and a path.
  *
@@ -373,7 +360,6 @@ WALLY_CORE_API int bip32_key_with_tweak_from_parent_path(
     size_t child_path_len,
     uint32_t flags,
     struct ext_key *output);
-#endif
 
 /**
  * As per `bip32_key_with_tweak_from_parent_path`, but allocates the key.
@@ -401,7 +387,6 @@ WALLY_CORE_API int bip32_key_to_base58(
     uint32_t flags,
     char **output);
 
-#ifndef SWIG
 /**
  * Convert a base58 encoded extended key to an extended key.
  *
@@ -421,7 +406,6 @@ WALLY_CORE_API int bip32_key_from_base58_n(
     const char *base58,
     size_t base58_len,
     struct ext_key *output);
-#endif
 
 /**
  * As per `bip32_key_from_base58`, but allocates the key.

include/wally_bip39.h

@@ -103,7 +103,6 @@ WALLY_CORE_API int bip39_mnemonic_validate(
     const struct words *w,
     const char *mnemonic);
 
-#ifndef SWIG
 /**
  * Convert a mnemonic into a binary seed.
  *
@@ -119,7 +118,6 @@ WALLY_CORE_API int bip39_mnemonic_to_seed(
     unsigned char *bytes_out,
     size_t len,
     size_t *written);
-#endif /* SWIG */
 
 /**
  * Convert a mnemonic into a binary seed of 512 bits.

include/wally_map.h

@@ -34,7 +34,6 @@ struct wally_map {
 };
 #endif /* SWIG */
 
-#ifndef SWIG
 /**
  * Initialize a new map.
  *
@@ -45,7 +44,6 @@ WALLY_CORE_API int wally_map_init(
     size_t allocation_len,
     wally_map_verify_fn_t verify_fn,
     struct wally_map *output);
-#endif /* SWIG_PYTHON */
 
 /**
  * Allocate and initialize a new map.
@@ -378,7 +376,6 @@ WALLY_CORE_API int wally_map_keypath_get_bip32_key_from_alloc(
     const struct ext_key *hdkey,
     struct ext_key **output);
 
-#ifndef SWIG
 /**
  * Verify a PSBT keypath keyed by a serialized bip32 extended public key.
  *
@@ -420,7 +417,6 @@ WALLY_CORE_API int wally_keypath_xonly_public_key_verify(
     size_t key_len,
     const unsigned char *val,
     size_t val_len);
-#endif /* SWIG */
 
 /**
  * Allocate and initialize a new BIP32 keypath map.

include/wally_psbt.h

@@ -133,7 +133,6 @@ struct wally_psbt {
 };
 #endif /* SWIG */
 
-#ifndef SWIG
 /**
  * Set the previous txid in an input.
  *
@@ -1806,7 +1805,6 @@ WALLY_CORE_API int wally_psbt_output_get_blinding_status(
     uint32_t flags,
     size_t *written);
 #endif /* BUILD_ELEMENTS */
-#endif /* SWIG */
 
 /**
  * Allocate and initialize a new PSBT.
@@ -2142,7 +2140,6 @@ WALLY_CORE_API int wally_psbt_clone_alloc(
     uint32_t flags,
     struct wally_psbt **output);
 
-#ifndef SWIG
 /**
  * Blind a PSBT.
  *
@@ -2171,7 +2168,6 @@ WALLY_CORE_API int wally_psbt_blind(
     uint32_t output_index,
     uint32_t flags,
     struct wally_map *output);
-#endif
 
 /**
  * Blind a PSBT.

include/wally_transaction.h

@@ -205,15 +205,13 @@ WALLY_CORE_API int wally_tx_witness_stack_set_dummy(
     size_t index,
     uint32_t flags);
 
-#ifndef SWIG_PYTHON
 /**
  * Free a transaction witness stack allocated by `wally_tx_witness_stack_init_alloc`.
  *
  * :param stack: The transaction witness stack to free.
  */
 WALLY_CORE_API int wally_tx_witness_stack_free(
     struct wally_tx_witness_stack *stack);
-#endif /* SWIG_PYTHON */
 
 /**
  * Allocate and initialize a new transaction input.
@@ -238,16 +236,13 @@ WALLY_CORE_API int wally_tx_input_init_alloc(
     const struct wally_tx_witness_stack *witness,
     struct wally_tx_input **output);
 
-#ifndef SWIG_PYTHON
 /**
  * Free a transaction input allocated by `wally_tx_input_init_alloc`.
  *
  * :param input: The transaction input to free.
  */
 WALLY_CORE_API int wally_tx_input_free(struct wally_tx_input *input);
-#endif /* SWIG_PYTHON */
 
-#ifndef SWIG
 /**
  * Initialize a new transaction output.
  *
@@ -260,7 +255,6 @@ WALLY_CORE_API int wally_tx_output_init(uint64_t satoshi,
                                         const unsigned char *script,
                                         size_t script_len,
                                         struct wally_tx_output *output);
-#endif /* SWIG */
 
 /**
  * Allocate and initialize a new transaction output.
@@ -286,7 +280,6 @@ WALLY_CORE_API int wally_tx_output_clone_alloc(
     const struct wally_tx_output *tx_output_in,
     struct wally_tx_output **output);
 
-#ifndef SWIG
 /**
  * Create a new copy of a transaction output in place.
  *
@@ -298,16 +291,13 @@ WALLY_CORE_API int wally_tx_output_clone_alloc(
 WALLY_CORE_API int wally_tx_output_clone(
     const struct wally_tx_output *tx_output_in,
     struct wally_tx_output *output);
-#endif /* SWIG */
 
-#ifndef SWIG_PYTHON
 /**
  * Free a transaction output allocated by `wally_tx_output_init_alloc`.
  *
  * :param output: The transaction output to free.
  */
 WALLY_CORE_API int wally_tx_output_free(struct wally_tx_output *output);
-#endif /* SWIG_PYTHON */
 
 /**
  * Allocate and initialize a new transaction.
@@ -524,14 +514,12 @@ WALLY_CORE_API int wally_tx_get_witness_count(
     const struct wally_tx *tx,
     size_t *written);
 
-#ifndef SWIG_PYTHON
 /**
  * Free a transaction allocated by `wally_tx_init_alloc`.
  *
  * :param tx: The transaction to free.
  */
 WALLY_CORE_API int wally_tx_free(struct wally_tx *tx);
-#endif /* SWIG_PYTHON */
 
 /**
  * Return the txid of a transaction.
@@ -761,15 +749,13 @@ WALLY_CORE_API int wally_tx_elements_input_issuance_set(
     const unsigned char *inflation_keys_rangeproof,
     size_t inflation_keys_rangeproof_len);
 
-#ifndef SWIG_PYTHON
 /**
  * Free issuance data on an input.
  *
  * :param input: The input issuance data to free.
  */
 WALLY_CORE_API int wally_tx_elements_input_issuance_free(
     struct wally_tx_input *input);
-#endif /* SWIG_PYTHON */
 
 /**
  * Allocate and initialize a new elements transaction input.
@@ -858,17 +844,14 @@ WALLY_CORE_API int wally_tx_elements_output_commitment_set(
     const unsigned char *rangeproof,
     size_t rangeproof_len);
 
-#ifndef SWIG_PYTHON
 /**
  * Free commitment data on an output.
  *
  * :param output: The output with the commitment data to free.
  */
 WALLY_CORE_API int wally_tx_elements_output_commitment_free(
     struct wally_tx_output *output);
-#endif /* SWIG_PYTHON */
 
-#ifndef SWIG
 /**
  * Initialize a new elements transaction output in place.
  *
@@ -902,7 +885,6 @@ WALLY_CORE_API int wally_tx_elements_output_init(
     const unsigned char *rangeproof,
     size_t rangeproof_len,
     struct wally_tx_output *output);
-#endif /* SWIG */
 
 /**
  * Allocate and initialize a new elements transaction output.