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rust-bitcoin-unsafe-fast
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Remove pile of undefined (and bitrotted) code

This commit is contained in:
Andrew Poelstra 2015-05-10 11:12:37 -05:00
parent b21acd440e
commit 2975c91e37
1 changed files with 3 additions and 26 deletions
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29
src/blockdata/blockchain.rs
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@ -375,32 +375,9 @@ impl Blockchain {
fn replace_txdata(&mut self, hash: &Uint256, txdata: Vec<Transaction>, has_txdata: bool) -> Result<(), util::Error> {
match self.tree.lookup_mut(hash, 256) {
Some(existing_block) => {
unsafe {
// existing_block is an Rc. Rust will not let us mutate it under
// any circumstances, since if it were to be reallocated, then
// all other references to it would be destroyed. However, we
// just need a mutable pointer to the txdata vector; by calling
// Vec::clone_from() rather than assigning, we can be assured that
// no reallocation can occur, since clone_from() takes an &mut self,
// which it does not own and therefore cannot move.
//
// To be clear: there will undoubtedly be some reallocation within
// the Vec itself. We don't care about this. What we care about is
// that the Vec (and more pointedly, its containing struct) does not
// move, since this would invalidate the Rc that we are snookering.
use std::mem::{forget, transmute};
let mutable_vec: &mut Vec<Transaction> = transmute(&existing_block.block.txdata);
mutable_vec.clone_from(&txdata);
// If mutable_vec went out of scope unhindered, it would deallocate
// the Vec it points to, since Rust assumes that a mutable vector
// is a unique reference (and this one is definitely not).
forget(mutable_vec);
// Do the same thing with the txdata flac
let mutable_bool: &mut bool = transmute(&existing_block.has_txdata);
*mutable_bool = has_txdata;
forget(mutable_bool);
}
Some(mut existing_block) => {
existing_block.block.txdata.clone_from(&txdata);
existing_block.has_txdata = has_txdata;
Ok(())
},
None => Err(BlockNotFound)