Move block filters to a dedicated module

Cargo.toml

@@ -5,6 +5,7 @@ members = [
     "crates/floresta-chain",
     "crates/floresta-cli",
     "crates/floresta-common",
+    "crates/floresta-compact-filters",
     "crates/floresta-electrum",
     "crates/floresta-watch-only",
     "crates/floresta-wire",

crates/floresta-compact-filters/Cargo.toml

@@ -0,0 +1,17 @@
+[package]
+name = "floresta-compact-filters"
+version = "0.1.0"
+authors = ["Davidson Sousa <[email protected]>"]
+edition = "2018"
+homepage = "https://github.com/davidson-souza/floresta"
+repository = "https://github.com/davidson-souza/floresta"
+description = """
+                BIP158 compact filters for easy rescan of the blockchain in 
+                light clients.
+            """
+
+[dependencies]
+bitcoin_hashes = "0.11.0"
+bitcoin = "0.29"
+floresta-common = { path = "../floresta-common" }
+kv = "0.24.0"

crates/floresta-watch-only/src/block_filter.rs → crates/floresta-compact-filters/src/lib.rs

@@ -1,22 +1,3 @@
-// SPDX-License-Identifier: MIT
-
-//! A module that uses BIP-158 block filters to sync our wallet
-
-//! BIP-158 client-side filters are a special probabilistic filter that can 
-//! quasi-succinctly represent a set of elements, determine whether an element 
-//! is present in the original set by querying the filter itself. 
-//!
-//! As a probabilistic filter, it has false-positives, i.e., elements that aren't in the set returning
-//! true. The false-positive rate can be tweaked and made manageable.
-//!
-//! This module doesn't use BIP-157 to download block filters from peers; instead, we build
-//! them locally, using the actual blocks. This gives us protection against malicious peers
-//! and control over what is indexed, reducing disk and CPU usage as required by our user.
-//!
-//! You can build a filter by calling `filter_block`, and query our blocks by calling
-//! `match_any`. The latter method returns a list of block heights where our filter queries 
-//! returned true; you should then download those blocks and check if there's something we  are interested in.
-
 use std::io::Write;
 
 use bitcoin::{
@@ -84,7 +65,7 @@ pub struct BlockFilterBackend {
     k0: u64,
     /// The second half of the siphash key
     k1: u64,
-    /// A block hash used to salt the siphash, we use a random hash instead of 
+    /// A block hash used to salt the siphash, we use a random hash instead of
     /// an actual block hash
     key: BlockHash,
 }
@@ -111,7 +92,7 @@ impl BlockFilterBackend {
     pub fn new(storage: Box<dyn BlockFilterStore>, key: BlockHash) -> BlockFilterBackend {
         let mut k0 = [0_u8; 8];
         let mut k1 = [0_u8; 8];
-        
+
         k0.copy_from_slice(&key[0..8]);
         k1.copy_from_slice(&key[8..16]);
 
@@ -213,7 +194,7 @@ pub struct FilterBackendBuilder {
     whitelisted_outputs: u8,
     index_input: bool,
     index_txids: bool,
-    key: [u8; 32]    
+    key: [u8; 32],
 }
 
 impl FilterBackendBuilder {
@@ -256,7 +237,7 @@ impl FilterBackendBuilder {
     }
     /// A key used by siphash
     ///
-    /// BIP-158 uses the block hash, but we use a fixed by here, so we don't 
+    /// BIP-158 uses the block hash, but we use a fixed by here, so we don't
     /// need to access chaindata on query
     pub fn key_hash(&mut self, key: [u8; 32]) -> &mut Self {
         self.key = key;
@@ -269,10 +250,10 @@ impl FilterBackendBuilder {
     pub fn build(self) -> BlockFilterBackend {
         let mut k0 = [0_u8; 8];
         let mut k1 = [0_u8; 8];
-        
+
         k0.copy_from_slice(&self.key[0..8]);
         k1.copy_from_slice(&self.key[8..16]);
-        
+
         BlockFilterBackend {
             key: BlockHash::from_inner(self.key),
             whitelisted_outputs: self.whitelisted_outputs,
@@ -338,10 +319,10 @@ mod tests {
         consensus::deserialize,
         hashes::{hex::FromHex, Hash},
         util::bip158,
-        Block, BlockHash, OutPoint, Txid, Script,
+        Block, BlockHash, OutPoint, Script, Txid,
     };
 
-    use crate::block_filter::QueryType;
+    use crate::QueryType;
 
     use super::{BlockFilterBackend, FilterBuilder, MemoryBlockFilterStorage};
     #[test]
@@ -395,7 +376,7 @@ mod tests {
             }
             .into(),
         );
-        // One spk from this block 
+        // One spk from this block
         let spck = Script::from_hex("0014fabea557d8541249533fe281aac45c37b2dbf342").unwrap();
         let spck = QueryType::ScriptHash(floresta_common::get_spk_hash(&spck).into_inner());
 

crates/floresta-watch-only/src/lib.rs

@@ -3,7 +3,6 @@ use core::{cmp::Ordering, fmt::Debug};
 
 use floresta_common::{get_spk_hash, parse_descriptors};
 
-pub mod block_filter;
 pub mod kv_database;
 #[cfg(any(test, feature = "memory-database"))]
 pub mod memory_database;