ffi: move Raw* structs out of FFI crate

These structures are private data types used ephemerally by
src/jet/elements/c_env.rs. They should not be public and certainly
should not be exposed in simplicity-sys.

Author: apoelstra

simplicity-sys/src/c_jets/c_env/elements.rs

@@ -5,57 +5,13 @@ use hashes::{sha256, Hash};
 use crate::ffi::sha256::CSha256Midstate;
 use crate::ffi::{c_size_t, c_uchar, c_uint, c_uint_fast32_t};
 
-/// Documentation of RawInputData/RawOutputData/RawTapData/Raw.
-///
-/// Data structure for holding data that CTransaction points to.
-///
-/// Why do we this special data structure?
-///     1. We need to keep the data in memory until the CTransaction is dropped.
-///     2. The memory is Transaction is not saved in the same format as required by FFI.
-/// We use more ergonomics in rust to allow better UX which interfere with the FFI. For example,
-/// the Value is stored as Tagged Union, but we require it to be a slice of bytes in elements format.
-///     3. Allocating inside FFI functions does not work because the memory is freed after the function returns.
-///     4. We only create allocations for data fields that are stored differently from the
-/// consensus serialization format.
-#[derive(Debug)]
-pub struct RawOutputData {
-    pub asset: Option<[c_uchar; 33]>,
-    pub value: Vec<c_uchar>,
-    pub nonce: Option<[c_uchar; 33]>,
-    pub surjection_proof: Vec<c_uchar>,
-    pub range_proof: Vec<c_uchar>,
-}
-
 #[derive(Debug)]
 #[repr(C)]
 pub struct CRawBuffer {
     pub ptr: *const c_uchar,
     pub len: u32,
 }
 
-/// Similar to [`RawOutputData`], for inputs.
-#[derive(Debug)]
-pub struct RawInputData {
-    pub annex: Option<Vec<c_uchar>>,
-    // pegin
-    pub genesis_hash: Option<[c_uchar; 32]>,
-    // issuance
-    pub issuance_amount: Vec<c_uchar>,
-    pub issuance_inflation_keys: Vec<c_uchar>,
-    pub amount_range_proof: Vec<c_uchar>,
-    pub inflation_keys_range_proof: Vec<c_uchar>,
-    // spent txo
-    pub asset: Option<[c_uchar; 33]>,
-    pub value: Vec<c_uchar>,
-}
-
-/// Similar to [`RawOutputData`], but for transaction
-#[derive(Debug)]
-pub struct RawTransactionData {
-    pub inputs: Vec<RawInputData>,
-    pub outputs: Vec<RawOutputData>,
-}
-
 #[derive(Debug)]
 #[repr(C)]
 pub struct CRawOutput<'raw> {

src/jet/elements/c_env.rs

@@ -18,9 +18,46 @@ use crate::merkle::cmr::Cmr;
 
 use super::ElementsUtxo;
 
+/// Holds transaction output data which needs to be re-serialized before being
+/// passed to the C FFI.
+#[derive(Debug)]
+struct RawOutputData {
+    pub asset: Option<[c_uchar; 33]>,
+    pub value: Vec<c_uchar>,
+    pub nonce: Option<[c_uchar; 33]>,
+    pub surjection_proof: Vec<c_uchar>,
+    pub range_proof: Vec<c_uchar>,
+}
+
+/// Holds transaction input data which needs to be re-serialized before being
+/// passed to the C FFI.
+#[derive(Debug)]
+struct RawInputData {
+    #[allow(dead_code)] // see FIXME below
+    pub annex: Option<Vec<c_uchar>>,
+    // pegin
+    pub genesis_hash: Option<[c_uchar; 32]>,
+    // issuance
+    pub issuance_amount: Vec<c_uchar>,
+    pub issuance_inflation_keys: Vec<c_uchar>,
+    pub amount_range_proof: Vec<c_uchar>,
+    pub inflation_keys_range_proof: Vec<c_uchar>,
+    // spent txo
+    pub asset: Option<[c_uchar; 33]>,
+    pub value: Vec<c_uchar>,
+}
+
+/// Holds transaction data which needs to be re-serialized before being
+/// passed to the C FFI.
+#[derive(Debug)]
+struct RawTransactionData {
+    pub inputs: Vec<RawInputData>,
+    pub outputs: Vec<RawOutputData>,
+}
+
 fn new_raw_output<'raw>(
     out: &elements::TxOut,
-    out_data: &'raw c_elements::RawOutputData,
+    out_data: &'raw RawOutputData,
 ) -> c_elements::CRawOutput<'raw> {
     c_elements::CRawOutput {
         asset: out_data.asset.as_ref(),
@@ -35,7 +72,7 @@ fn new_raw_output<'raw>(
 fn new_raw_input<'raw>(
     inp: &'raw elements::TxIn,
     in_utxo: &'raw ElementsUtxo,
-    inp_data: &'raw c_elements::RawInputData,
+    inp_data: &'raw RawInputData,
 ) -> c_elements::CRawInput<'raw> {
     c_elements::CRawInput {
         // FIXME actually pass the annex in; see https://github.com/BlockstreamResearch/simplicity/issues/311 for some difficulty here.
@@ -70,16 +107,13 @@ fn new_raw_input<'raw>(
     }
 }
 
-fn new_tx_data(
-    tx: &elements::Transaction,
-    in_utxos: &[ElementsUtxo],
-) -> c_elements::RawTransactionData {
-    let mut tx_data = c_elements::RawTransactionData {
+fn new_tx_data(tx: &elements::Transaction, in_utxos: &[ElementsUtxo]) -> RawTransactionData {
+    let mut tx_data = RawTransactionData {
         inputs: Vec::with_capacity(tx.input.len()),
         outputs: Vec::with_capacity(tx.output.len()),
     };
     for (inp, in_utxo) in tx.input.iter().zip(in_utxos.iter()) {
-        let inp_data = c_elements::RawInputData {
+        let inp_data = RawInputData {
             annex: None, // Actually store annex
             genesis_hash: inp
                 .pegin_data()
@@ -96,7 +130,7 @@ fn new_tx_data(
         tx_data.inputs.push(inp_data);
     }
     for out in &tx.output {
-        let out_data = c_elements::RawOutputData {
+        let out_data = RawOutputData {
             asset: asset_array(&out.asset),
             value: serialize(&out.value),
             nonce: nonce_array(&out.nonce),