ffi: remove c_set_rawElementsTapEnv

Author: apoelstra

simplicity-sys/depend/env.c

@@ -25,11 +25,6 @@ const size_t rustsimplicity_0_5_c_alignof_rawElementsTransaction = alignof(rawEl
 const size_t rustsimplicity_0_5_c_alignof_rawElementsTapEnv = alignof(rawElementsTapEnv);
 const size_t rustsimplicity_0_5_c_alignof_txEnv = alignof(txEnv);
 
-void rustsimplicity_0_5_c_set_rawElementsTapEnv(rawElementsTapEnv *result, const unsigned char *controlBlock, unsigned char pathLen, const unsigned char *scriptCMR)
-{
-    *result = (rawElementsTapEnv){.controlBlock = controlBlock, .pathLen = pathLen, .scriptCMR = scriptCMR};
-}
-
 void rustsimplicity_0_5_c_set_txEnv(txEnv *result, const elementsTransaction *tx, const elementsTapEnv *taproot, const unsigned char *genesisHash, unsigned int ix)
 {
     sha256_midstate genesis;

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

@@ -125,9 +125,9 @@ pub struct CRawTransaction<'raw> {
 #[derive(Debug)]
 #[repr(C)]
 pub struct CRawTapEnv {
-    control_block: *const c_uchar,
-    script_cmr: *const c_uchar,
-    branch_len: u8,
+    pub control_block: *const c_uchar,
+    pub script_cmr: *const c_uchar,
+    pub branch_len: u8,
 }
 
 #[derive(Debug)]
@@ -173,13 +173,6 @@ extern "C" {
     #[link_name = "rustsimplicity_0_5_c_alignof_txEnv"]
     pub static c_alignof_txEnv: c_size_t;
 
-    #[link_name = "rustsimplicity_0_5_c_set_rawElementsTapEnv"]
-    pub fn c_set_rawTapEnv(
-        result: *mut CRawTapEnv,
-        controlBlock: *const c_uchar,
-        pathLen: c_uchar,
-        scriptCMR: *const c_uchar,
-    );
     #[link_name = "rustsimplicity_0_5_c_set_txEnv"]
     pub fn c_set_txEnv(
         result: *mut CTxEnv,

src/jet/elements/c_env.rs

@@ -148,16 +148,20 @@ pub(super) fn new_tap_env(
     control_block: &ControlBlock,
     script_cmr: Cmr,
 ) -> *mut c_elements::CTapEnv {
+    let cb_ser = control_block.serialize();
+    let raw_tap_env = c_elements::CRawTapEnv {
+        control_block: cb_ser.as_ptr(),
+        script_cmr: script_cmr.as_ref().as_ptr(),
+        branch_len: control_block
+            .merkle_branch
+            .as_inner()
+            .len()
+            .try_into()
+            .expect("sane length"),
+    };
+
     unsafe {
-        let mut raw_tap_env = std::mem::MaybeUninit::<c_elements::CRawTapEnv>::uninit();
-        let cb_ser = control_block.serialize();
-        c_elements::c_set_rawTapEnv(
-            raw_tap_env.as_mut_ptr(),
-            cb_ser.as_ptr(),
-            control_block.merkle_branch.as_inner().len() as c_uchar,
-            script_cmr.as_ref().as_ptr(),
-        );
-        let raw_tap_env = raw_tap_env.assume_init();
+        // SAFETY: this is a FFI call and we constructed its argument correctly.
         c_elements::simplicity_mallocTapEnv(&raw_tap_env)
     }
 }