diff --git a/zcash_history/.gitignore b/zcash_history/.gitignore new file mode 100644 index 0000000..293dd90 --- /dev/null +++ b/zcash_history/.gitignore @@ -0,0 +1,4 @@ +/target +**/*.rs.bk +Cargo.lock +.idea \ No newline at end of file diff --git a/zcash_history/.travis.yml b/zcash_history/.travis.yml new file mode 100644 index 0000000..00e7694 --- /dev/null +++ b/zcash_history/.travis.yml @@ -0,0 +1,4 @@ +language: rust +rust: +- nightly +- stable \ No newline at end of file diff --git a/zcash_history/Cargo.toml b/zcash_history/Cargo.toml new file mode 100644 index 0000000..d527675 --- /dev/null +++ b/zcash_history/Cargo.toml @@ -0,0 +1,14 @@ +[package] +name = "zcash_mmr" +version = "0.1.0" +authors = ["NikVolf "] +edition = "2018" + +[dev-dependencies] +assert_matches = "1.3.0" +quickcheck = "0.8" + +[dependencies] +bigint = "4" +byteorder = "1" +blake2 = { package = "blake2b_simd", version = "0.5" } diff --git a/zcash_history/LICENSE-APACHE b/zcash_history/LICENSE-APACHE new file mode 100644 index 0000000..16fe87b --- /dev/null +++ b/zcash_history/LICENSE-APACHE @@ -0,0 +1,201 @@ + Apache License + Version 2.0, January 2004 + http://www.apache.org/licenses/ + +TERMS AND CONDITIONS FOR USE, REPRODUCTION, AND DISTRIBUTION + +1. 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We also recommend that a + file or class name and description of purpose be included on the + same "printed page" as the copyright notice for easier + identification within third-party archives. + +Copyright [yyyy] [name of copyright owner] + +Licensed under the Apache License, Version 2.0 (the "License"); +you may not use this file except in compliance with the License. +You may obtain a copy of the License at + + http://www.apache.org/licenses/LICENSE-2.0 + +Unless required by applicable law or agreed to in writing, software +distributed under the License is distributed on an "AS IS" BASIS, +WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. +See the License for the specific language governing permissions and +limitations under the License. diff --git a/zcash_history/LICENSE-MIT b/zcash_history/LICENSE-MIT new file mode 100644 index 0000000..5ee6ad6 --- /dev/null +++ b/zcash_history/LICENSE-MIT @@ -0,0 +1,25 @@ +Copyright (c) 2019 Nikolay Volf + +Permission is hereby granted, free of charge, to any +person obtaining a copy of this software and associated +documentation files (the "Software"), to deal in the +Software without restriction, including without +limitation the rights to use, copy, modify, merge, +publish, distribute, sublicense, and/or sell copies of +the Software, and to permit persons to whom the Software +is furnished to do so, subject to the following +conditions: + +The above copyright notice and this permission notice +shall be included in all copies or substantial portions +of the Software. + +THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF +ANY KIND, EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED +TO THE WARRANTIES OF MERCHANTABILITY, FITNESS FOR A +PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT +SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY +CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION +OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR +IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER +DEALINGS IN THE SOFTWARE. diff --git a/zcash_history/README.md b/zcash_history/README.md new file mode 100644 index 0000000..f034137 --- /dev/null +++ b/zcash_history/README.md @@ -0,0 +1,26 @@ +# zcash_mmr + +Special implementation of Merkle mountain ranges (MMR) for Zcash! + +[![Build Status](https://travis-ci.org/NikVolf/zcash-mmr.svg?branch=master)](https://travis-ci.org/NikVolf/zcash-mmr) + +The main design goals of this MMR implementation are + +- Allow zero-cache and avoid db callbacks. As it is implemented, calling side must just smartly pre-load MMR nodes from the database (about log2(tree length) for append, twice as much for deletion). + +- Reuse as much logic between rust and c++ clients and place it here and librustzcash. + +- Close to zero memory consumption. + +# License + +`zcash_mmr` is distributed under the terms of both the MIT +license and the Apache License (Version 2.0), at your choice. + +See LICENSE-APACHE, and LICENSE-MIT for details. + +### Contribution + +Unless you explicitly state otherwise, any contribution intentionally submitted +for inclusion in `zcash_mmr` by you, as defined in the Apache-2.0 license, shall be +dual licensed as above, without any additional terms or conditions. diff --git a/zcash_history/examples/lib/main.rs b/zcash_history/examples/lib/main.rs new file mode 100644 index 0000000..6850079 --- /dev/null +++ b/zcash_history/examples/lib/main.rs @@ -0,0 +1,4 @@ +// dummy example +pub fn main() { + +} \ No newline at end of file diff --git a/zcash_history/examples/lib/shared.rs b/zcash_history/examples/lib/shared.rs new file mode 100644 index 0000000..4cd9262 --- /dev/null +++ b/zcash_history/examples/lib/shared.rs @@ -0,0 +1,78 @@ +use zcash_mmr:: {NodeData, Tree, Entry, EntryLink}; + +pub struct NodeDataIterator { + return_stack: Vec, + tree: Tree, + cursor: usize, + leaf_cursor: usize, +} + +impl Iterator for NodeDataIterator { + type Item = NodeData; + + fn next(&mut self) -> Option { + let result = if self.cursor == 1 { + self.leaf_cursor = 2; + Some(leaf(1)) + } else if self.cursor == 2 { + self.leaf_cursor = 3; + Some(leaf(2)) + } else if self.cursor == 3 { + Some(self.tree.root_node().expect("always exists").data().clone()) + } else if self.return_stack.len() > 0 { + self.return_stack.pop() + } else { + for n_append in + self.tree.append_leaf(leaf(self.leaf_cursor as u32)) + .expect("full tree cannot fail").into_iter().rev() + { + self.return_stack.push(self.tree.resolve_link(n_append).expect("just pushed").data().clone()) + } + self.leaf_cursor += 1; + self.return_stack.pop() + }; + + self.cursor += 1; + result + } +} + +impl NodeDataIterator { + pub fn new() -> Self { + let root = Entry::new( + NodeData::combine(&leaf(1), &leaf(2)), + EntryLink::Stored(0), + EntryLink::Stored(1) + ); + let tree = + Tree::new( + 3, + vec![(2, root)], + vec![(0, leaf(1).into()), (1, leaf(2).into())] + ); + + NodeDataIterator { + return_stack: Vec::new(), + tree, + cursor: 1, + leaf_cursor: 1, + } + } +} + +fn leaf(height: u32) -> NodeData { + NodeData { + consensus_branch_id: 0, + subtree_commitment: [0u8; 32], + start_time: height*10+1, + end_time: (height+1)*10, + start_target: 100 + height*10, + end_target: 100 + (height+1)*10, + start_sapling_root: [0u8; 32], + end_sapling_root: [0u8; 32], + subtree_total_work: 0.into(), + start_height: height as u64, + end_height: height as u64, + shielded_tx: 5 + height as u64, + } +} diff --git a/zcash_history/examples/long.rs b/zcash_history/examples/long.rs new file mode 100644 index 0000000..951d226 --- /dev/null +++ b/zcash_history/examples/long.rs @@ -0,0 +1,109 @@ +use zcash_mmr::{Entry, EntryLink, NodeData, Tree}; + +#[path= "lib/shared.rs"] +mod share; + +fn draft(into: &mut Vec<(u32, Entry)>, vec: &Vec, peak_pos: usize, h: u32) { + let node_data = vec[peak_pos-1].clone(); + let peak: Entry = match h { + 0 => node_data.into(), + _ => Entry::new( + node_data, + EntryLink::Stored((peak_pos - (1 << h) - 1) as u32), + EntryLink::Stored((peak_pos - 2) as u32), + ), + }; + + println!("Entry #{}: {}", into.len(), peak); + + into.push(((peak_pos-1) as u32, peak)); +} + +fn prepare_tree(vec: &Vec) -> Tree { + + assert!(vec.len() > 0); + + // integer log2 of (vec.len()+1), -1 + let mut h = (32 - ((vec.len()+1) as u32).leading_zeros() - 1)-1; + let mut peak_pos = (1 << (h+1)) - 1; + let mut nodes = Vec::new(); + + // used later + let mut last_peak_pos = 0; + let mut last_peak_h = 0; + + loop { + + if peak_pos > vec.len() { + // left child, -2^h + peak_pos = peak_pos - (1< 0 { + let left_pos = peak_pos - (1< { eprintln!("writer []"); std::process::exit(1); }, + Some(number) => { + number.parse::().expect("invalid number") + } + }; + + let long_vec = share::NodeDataIterator::new().take(number) + .collect::>(); + + let now = std::time::Instant::now(); + + let tree = prepare_tree(&long_vec); + let elapsed = now.elapsed(); + + println!("Tree final root: {}-{}", + tree.root_node().expect("root").data().start_height, + tree.root_node().expect("root").data().end_height, + ); + + println!("Prepare tree of {} length: {} ns / {} mcs / {} ms", + number, + elapsed.as_nanos(), elapsed.as_micros(), elapsed.as_millis() + ); +} diff --git a/zcash_history/examples/write.rs b/zcash_history/examples/write.rs new file mode 100644 index 0000000..c029a85 --- /dev/null +++ b/zcash_history/examples/write.rs @@ -0,0 +1,41 @@ +#[path= "lib/shared.rs"] +mod share; + +// Test data generator +// $ cargo run --example writer -- 16 nodes.dat +// or +// $ cargo run --example writer -- 16 +// to preview + +fn main() { + let mut args = std::env::args().skip(1); + + let (number, out_file) = match args.next() { + None => { eprintln!("writer []"); std::process::exit(1); }, + Some(number) => { + (number.parse::().expect("invalid number"), args.next()) + } + }; + + let iterator = share::NodeDataIterator::new().take(number); + + if let Some(out_file_path) = out_file { + use std::io::Write; + + let mut buf = Vec::new(); + + for node in iterator{ + node.write(&mut buf).expect("Failed to write data"); + } + + let mut file = std::fs::File::create(&out_file_path) + .expect("Failed to create output file"); + + file.write_all(&buf[..]) + .expect("Failed to write data to file"); + } else { + for n in iterator { + println!("{:?}", n); + } + } +} \ No newline at end of file diff --git a/zcash_history/src/entry.rs b/zcash_history/src/entry.rs new file mode 100644 index 0000000..ab95a38 --- /dev/null +++ b/zcash_history/src/entry.rs @@ -0,0 +1,121 @@ +use byteorder::{LittleEndian, ReadBytesExt, WriteBytesExt}; + +use crate::{EntryKind, NodeData, Error, EntryLink, MAX_NODE_DATA_SIZE}; + +/// Max serialized length of entry data. +pub const MAX_ENTRY_SIZE: usize = MAX_NODE_DATA_SIZE + 9; + +/// MMR Entry. +#[derive(Debug)] +pub struct Entry { + pub(crate) kind: EntryKind, + pub(crate) data: NodeData, +} + +impl Entry { + /// New entry of type node. + pub fn new(data: NodeData, left: EntryLink, right: EntryLink) -> Self { + Entry { + kind: EntryKind::Node(left, right), + data, + } + } + + /// Returns if is this node complete (has total of 2^N leaves) + pub fn complete(&self) -> bool { + let leaves = self.leaf_count(); + leaves & (leaves - 1) == 0 + } + + /// Number of leaves under this node. + pub fn leaf_count(&self) -> u64 { + self.data.end_height - (self.data.start_height - 1) + } + + /// Is this node a leaf. + pub fn leaf(&self) -> bool { + if let EntryKind::Leaf = self.kind { true } else { false } + } + + /// Left child + pub fn left(&self) -> Result { + match self.kind { + EntryKind::Leaf => { Err(Error::node_expected()) } + EntryKind::Node(left, _) => Ok(left) + } + } + + /// Right child. + pub fn right(&self) -> Result { + match self.kind { + EntryKind::Leaf => { Err(Error::node_expected()) } + EntryKind::Node(_, right) => Ok(right) + } + } + + /// Read from byte representation. + pub fn read(consensus_branch_id: u32, r: &mut R) -> std::io::Result { + let kind = { + match r.read_u8()? { + 0 => { + let left = r.read_u32::()?; + let right = r.read_u32::()?; + EntryKind::Node(EntryLink::Stored(left), EntryLink::Stored(right)) + }, + 1 => { + EntryKind::Leaf + }, + _ => { + return Err(std::io::Error::from(std::io::ErrorKind::InvalidData)) + }, + } + }; + + let data = NodeData::read(consensus_branch_id, r)?; + + Ok(Entry { + kind, + data, + }) + } + + /// Write to byte representation. + pub fn write(&self, w: &mut W) -> std::io::Result<()> { + match self.kind { + EntryKind::Node(EntryLink::Stored(left), EntryLink::Stored(right)) => { + w.write_u8(0)?; + w.write_u32::(left)?; + w.write_u32::(right)?; + }, + EntryKind::Leaf => { + w.write_u8(1)?; + }, + _ => { return Err(std::io::Error::from(std::io::ErrorKind::InvalidData)); } + } + + self.data.write(w)?; + + Ok(()) + } + + /// Convert from byte representation. + pub fn from_bytes>(consensus_branch_id: u32, buf: T) -> std::io::Result { + let mut cursor = std::io::Cursor::new(buf); + Self::read(consensus_branch_id, &mut cursor) + } +} + +impl From for Entry { + fn from(s: NodeData) -> Self { + Entry { kind: EntryKind::Leaf, data: s } + } +} + +impl std::fmt::Display for Entry { + fn fmt(&self, f: &mut std::fmt::Formatter<'_>) -> std::fmt::Result { + match self.kind { + EntryKind::Node(l, r) => write!(f, "node({}, {}, ..)", l, r), + EntryKind::Leaf => write!(f, "leaf(..)"), + } + } +} diff --git a/zcash_history/src/lib.rs b/zcash_history/src/lib.rs new file mode 100644 index 0000000..0c26dfa --- /dev/null +++ b/zcash_history/src/lib.rs @@ -0,0 +1,77 @@ +//! MMR library for Zcash +//! +//! To be used in zebra and via FFI bindings in zcashd +#![warn(missing_docs)] + +mod tree; +mod node_data; +mod entry; + + +pub use tree::Tree; +pub use node_data::{NodeData, MAX_NODE_DATA_SIZE}; +pub use entry::{Entry, MAX_ENTRY_SIZE}; + +/// Crate-level error type +#[derive(Debug)] +pub enum Error { + /// Entry expected to be presented in the tree view while it was not. + ExpectedInMemory(EntryLink), + /// Entry expected to be a node (specifying for which link this is not true). + ExpectedNode(Option), +} + +impl std::fmt::Display for Error { + fn fmt(&self, f: &mut std::fmt::Formatter<'_>) -> std::fmt::Result { + match *self { + Self::ExpectedInMemory(l) => write!(f, "Node/leaf expected to be in memory: {}", l), + Self::ExpectedNode(None) => write!(f, "Node expected"), + Self::ExpectedNode(Some(l)) => write!(f, "Node expected, not leaf: {}", l), + } + } +} + +/// Reference to to the tree node. +#[repr(C)] +#[derive(Clone, Copy, Debug)] +pub enum EntryLink { + /// Reference to the stored (in the array representation) leaf/node. + Stored(u32), + /// Reference to the generated leaf/node. + Generated(u32), +} + +impl std::fmt::Display for EntryLink { + fn fmt(&self, f: &mut std::fmt::Formatter<'_>) -> std::fmt::Result { + match *self { + Self::Stored(v) => write!(f, "stored({})", v), + Self::Generated(v) => write!(f, "generated({})", v), + } + } +} + +/// MMR Node. It is leaf when `left`, `right` are `None` and node when they are not. +#[repr(C)] +#[derive(Debug)] +pub enum EntryKind { + /// Leaf entry. + Leaf, + /// Node entry with children links. + Node(EntryLink, EntryLink), +} + +impl Error { + /// Entry expected to be a node (specifying for which link this is not true). + pub fn link_node_expected(link: EntryLink) -> Self { Self::ExpectedNode(Some(link)) } + + /// Some entry is expected to be node + pub fn node_expected() -> Self { Self::ExpectedNode(None) } + + pub (crate) fn augment(self, link: EntryLink) -> Self { + match self { + Error::ExpectedNode(_) => Error::ExpectedNode(Some(link)), + val => val + } + } +} + diff --git a/zcash_history/src/node_data.rs b/zcash_history/src/node_data.rs new file mode 100644 index 0000000..55b2df2 --- /dev/null +++ b/zcash_history/src/node_data.rs @@ -0,0 +1,239 @@ +use byteorder::{LittleEndian, ReadBytesExt, WriteBytesExt, ByteOrder}; +use bigint::U256; +use blake2::Params as Blake2Params; + +/// Maximum serialized size of the node metadata. +pub const MAX_NODE_DATA_SIZE: usize = + 32 + // subtree commitment + 4 + // start time + 4 + // end time + 4 + // start target + 4 + // end target + 32 + // start sapling tree root + 32 + // end sapling tree root + 32 + // subtree total work + 9 + // start height (compact uint) + 9 + // end height (compact uint) + 9; // shielded tx count (compact uint) + // = total of 171 + +/// Node metadata. +#[repr(C)] +#[derive(Debug, Clone, Default)] +#[cfg_attr(test, derive(PartialEq))] +pub struct NodeData { + /// Consensus branch id, should be provided by deserializing node. + pub consensus_branch_id: u32, + /// Subtree commitment - either block hash for leaves or hashsum of children for nodes. + pub subtree_commitment: [u8; 32], + /// Start time. + pub start_time: u32, + /// End time. + pub end_time: u32, + /// Start target. + pub start_target: u32, + /// End target. + pub end_target: u32, + /// Start sapling tree root. + pub start_sapling_root: [u8; 32], + /// End sapling tree root. + pub end_sapling_root: [u8; 32], + /// Part of tree total work. + pub subtree_total_work: U256, + /// Start height. + pub start_height: u64, + /// End height + pub end_height: u64, + /// Number of shielded transactions. + pub shielded_tx: u64, +} + +fn blake2b_personal(personalization: &[u8], input: &[u8]) -> [u8; 32] { + let hash_result = Blake2Params::new() + .hash_length(32) + .personal(personalization) + .to_state() + .update(input) + .finalize(); + let mut result = [0u8; 32]; + result.copy_from_slice(hash_result.as_bytes()); + result +} + +fn personalization(branch_id: u32) -> [u8; 16] { + let mut result = [0u8; 16]; + result[..12].copy_from_slice(b"ZcashHistory"); + LittleEndian::write_u32(&mut result[12..], branch_id); + result +} + +impl NodeData { + /// Combine two nodes metadata. + pub fn combine(left: &NodeData, right: &NodeData) -> NodeData { + assert_eq!(left.consensus_branch_id, right.consensus_branch_id); + + let mut hash_buf = [0u8; MAX_NODE_DATA_SIZE * 2]; + let size = { + let mut cursor = ::std::io::Cursor::new(&mut hash_buf[..]); + left.write(&mut cursor).expect("Writing to memory buf with enough length cannot fail; qed"); + right.write(&mut cursor).expect("Writing to memory buf with enough length cannot fail; qed"); + cursor.position() as usize + }; + + let hash = blake2b_personal( + &personalization(left.consensus_branch_id), + &hash_buf[..size] + ); + + NodeData { + consensus_branch_id: left.consensus_branch_id, + subtree_commitment: hash, + start_time: left.start_time, + end_time: right.end_time, + start_target: left.start_target, + end_target: right.end_target, + start_sapling_root: left.start_sapling_root, + end_sapling_root: right.end_sapling_root, + subtree_total_work: left.subtree_total_work + right.subtree_total_work, + start_height: left.start_height, + end_height: right.end_height, + shielded_tx: left.shielded_tx + right.shielded_tx, + } + } + + fn write_compact(w: &mut W, compact: u64) -> std::io::Result<()> { + match compact { + 0..=0xfc => { + w.write_all(&[compact as u8])? + }, + 0xfd..=0xffff => { + w.write_all(&[0xfd])?; + w.write_u16::(compact as u16)?; + }, + 0x10000..=0xffff_ffff => { + w.write_all(&[0xfe])?; + w.write_u32::(compact as u32)?; + }, + _ => { + w.write_all(&[0xff])?; + w.write_u64::(compact)?; + } + } + Ok(()) + } + + fn read_compact(reader: &mut R) -> std::io::Result { + let result = match reader.read_u8()? { + i @ 0..=0xfc => i.into(), + 0xfd => reader.read_u16::()?.into(), + 0xfe => reader.read_u32::()?.into(), + _ => reader.read_u64::()?, + }; + + Ok(result) + } + + /// Write to the byte representation. + pub fn write(&self, w: &mut W) -> std::io::Result<()> { + w.write_all(&self.subtree_commitment)?; + w.write_u32::(self.start_time)?; + w.write_u32::(self.end_time)?; + w.write_u32::(self.start_target)?; + w.write_u32::(self.end_target)?; + w.write_all(&self.start_sapling_root)?; + w.write_all(&self.end_sapling_root)?; + + let mut work_buf = [0u8; 32]; + self.subtree_total_work.to_little_endian(&mut work_buf[..]); + w.write_all(&work_buf)?; + + Self::write_compact(w, self.start_height)?; + Self::write_compact(w, self.end_height)?; + Self::write_compact(w, self.shielded_tx)?; + Ok(()) + } + + /// Read from the byte representation. + pub fn read(consensus_branch_id: u32, r: &mut R) -> std::io::Result { + let mut data = Self::default(); + data.consensus_branch_id = consensus_branch_id; + r.read_exact(&mut data.subtree_commitment)?; + data.start_time = r.read_u32::()?; + data.end_time = r.read_u32::()?; + data.start_target= r.read_u32::()?; + data.end_target= r.read_u32::()?; + r.read_exact(&mut data.start_sapling_root)?; + r.read_exact(&mut data.end_sapling_root)?; + + let mut work_buf = [0u8; 32]; + r.read_exact(&mut work_buf)?; + data.subtree_total_work = U256::from_little_endian(&work_buf); + + data.start_height = Self::read_compact(r)?; + data.end_height = Self::read_compact(r)?; + data.shielded_tx = Self::read_compact(r)?; + + Ok(data) + } + + /// Convert to byte representation. + pub fn to_bytes(&self) -> Vec { + let mut buf = [0u8; MAX_NODE_DATA_SIZE]; + let pos = { + let mut cursor = std::io::Cursor::new(&mut buf[..]); + self.write(&mut cursor).expect("Cursor cannot fail"); + cursor.position() as usize + }; + + buf[0..pos].to_vec() + } + + /// Convert from byte representation. + pub fn from_bytes>(consensus_branch_id: u32, buf: T) -> std::io::Result { + let mut cursor = std::io::Cursor::new(buf); + Self::read(consensus_branch_id, &mut cursor) + } + + /// Hash node metadata + pub fn hash(&self) -> [u8; 32] { + let bytes = self.to_bytes(); + + blake2b_personal(&personalization(self.consensus_branch_id), &bytes) + } +} + +#[cfg(test)] +impl quickcheck::Arbitrary for NodeData { + fn arbitrary(gen: &mut G) -> Self { + let mut node_data = NodeData::default(); + node_data.consensus_branch_id = 0; + gen.fill_bytes(&mut node_data.subtree_commitment[..]); + node_data.start_time = gen.next_u32(); + node_data.end_time = gen.next_u32(); + node_data.start_target = gen.next_u32(); + node_data.end_target = gen.next_u32(); + gen.fill_bytes(&mut node_data.start_sapling_root[..]); + gen.fill_bytes(&mut node_data.end_sapling_root[..]); + let mut number = [0u8; 32]; + gen.fill_bytes(&mut number[..]); + node_data.subtree_total_work = U256::from_little_endian(&number[..]); + node_data.start_height = gen.next_u64(); + node_data.end_height = gen.next_u64(); + node_data.shielded_tx = gen.next_u64(); + + node_data + } +} + +#[cfg(test)] +mod tests { + use super::NodeData; + use quickcheck::{quickcheck, TestResult}; + + + quickcheck! { + fn serialization_round_trip(node_data: NodeData) -> TestResult { + TestResult::from_bool(NodeData::from_bytes(0, &node_data.to_bytes()).unwrap() == node_data) + } + } +} \ No newline at end of file diff --git a/zcash_history/src/tree.rs b/zcash_history/src/tree.rs new file mode 100644 index 0000000..c020c72 --- /dev/null +++ b/zcash_history/src/tree.rs @@ -0,0 +1,756 @@ +use std::collections::HashMap; + +use crate::{Entry, EntryLink, NodeData, Error, EntryKind}; + +/// Represents partially loaded tree. +/// +/// Some kind of "view" into the array representation of the MMR tree. +/// With only some of the leaves/nodes pre-loaded / pre-generated. +/// Exact amount of the loaded data can be calculated by the constructing party, +/// depending on the length of the tree and maximum amount of operations that are going +/// to happen after construction. `Tree` should not be used as self-contained data structure, +/// since it's internal state can grow indefinitely after serial operations. +/// Intended use of this `Tree` is to instantiate it based on partially loaded data (see example +/// how to pick right nodes from the array representation of MMR Tree), perform several operations +/// (append-s/delete-s) and then drop it. +pub struct Tree { + stored: HashMap, + + // This can grow indefinitely if `Tree` is misused as a self-contained data structure + generated: Vec, + + // number of persistent(!) tree entries + stored_count: u32, + + root: EntryLink, +} + +impl Tree { + /// Resolve link originated from this tree + pub fn resolve_link(&self, link: EntryLink) -> Result { + match link { + EntryLink::Generated(index) => self.generated.get(index as usize), + EntryLink::Stored(index) => self.stored.get(&index), + } + .map(|node| IndexedNode { + node, + link, + }) + .ok_or(Error::ExpectedInMemory(link)) + } + + fn push(&mut self, data: Entry) -> EntryLink { + let idx = self.stored_count; + self.stored_count += 1; + self.stored.insert(idx, data); + EntryLink::Stored(idx) + } + + fn push_generated(&mut self, data: Entry) -> EntryLink { + self.generated.push(data); + EntryLink::Generated(self.generated.len() as u32 - 1) + } + + /// Populate tree with plain list of the leaves/nodes. For now, only for tests, + /// since this `Tree` structure is for partially loaded tree (but it might change) + #[cfg(test)] + pub fn populate(loaded: Vec, root: EntryLink) -> Self { + let mut result = Tree::invalid(); + result.stored_count = loaded.len() as u32; + for (idx, item) in loaded.into_iter().enumerate() { + result.stored.insert(idx as u32, item); + } + result.root = root; + + result + } + + // Empty tree with invalid root + fn invalid() -> Self { + Tree { + root: EntryLink::Generated(0), + generated: Default::default(), + stored: Default::default(), + stored_count: 0, + } + } + + /// New view into the the tree array representation + /// + /// `length` is total length of the array representation (is generally not a sum of + /// peaks.len + extra.len) + /// `peaks` is peaks of the mmr tree + /// `extra` is some extra nodes that calculated to be required during next one or more + /// operations on the tree. + /// + /// # Panics + /// + /// Will panic if `peaks` is empty. + pub fn new( + length: u32, + peaks: Vec<(u32, Entry)>, + extra: Vec<(u32, Entry)>, + ) -> Self { + assert!(peaks.len() > 0); + + let mut result = Tree::invalid(); + + result.stored_count = length; + + let mut gen = 0; + let mut root = EntryLink::Stored(peaks[0].0); + for (idx, node) in peaks.into_iter() { + result.stored.insert(idx, node); + if gen != 0 { + let next_generated = + combine_nodes(result. + resolve_link(root).expect("Inserted before, cannot fail; qed"), + result.resolve_link(EntryLink::Stored(idx)).expect("Inserted before, cannot fail; qed") + ); + root = result.push_generated(next_generated); + } + gen += 1; + } + + for (idx, node) in extra { + result.stored.insert(idx, node); + } + + result.root = root; + + result + } + + fn get_peaks(&self, root: EntryLink, target: &mut Vec) -> Result<(), Error> { + + let (left_child_link, right_child_link) = { + let root = self.resolve_link(root)?; + if root.node.complete() { + target.push(root.link); + return Ok(()); + } + ( + root.left()?, + root.right()?, + ) + }; + + self.get_peaks(left_child_link, target)?; + self.get_peaks(right_child_link, target)?; + Ok(()) + } + + /// Append one leaf to the tree. + /// + /// Returns links to actual nodes that has to be persisted as the result of the append. + /// If completed without error, at least one link to the appended + /// node (with metadata provided in `new_leaf`) will be returned. + pub fn append_leaf(&mut self, new_leaf: NodeData) -> Result, Error> { + let root = self.root; + let new_leaf_link = self.push(new_leaf.into()); + let mut appended = Vec::new(); + appended.push(new_leaf_link); + + let mut peaks = Vec::new(); + self.get_peaks(root, &mut peaks)?; + + let mut merge_stack = Vec::new(); + merge_stack.push(new_leaf_link); + + // Scan the peaks right-to-left, merging together equal-sized adjacent + // complete subtrees. After this, merge_stack only contains peaks of + // unequal-sized subtrees. + while let Some(next_peak) = peaks.pop() { + let next_merge = merge_stack.pop().expect("there should be at least one, initial or re-pushed"); + + if let Some(stored) = { + let peak = self.resolve_link(next_peak)?; + let m = self.resolve_link(next_merge)?; + if peak.node.leaf_count() == m.node.leaf_count() { + Some(combine_nodes(peak, m)) + } else { None } + } { + let link = self.push(stored); + merge_stack.push(link); + appended.push(link); + continue; + } else { + merge_stack.push(next_merge); + merge_stack.push(next_peak); + } + } + + let mut new_root = merge_stack.pop().expect("Loop above cannot reduce the merge_stack"); + // Scan the peaks left-to-right, producing new generated nodes that + // connect the subtrees + while let Some(next_child) = merge_stack.pop() { + new_root = self.push_generated( + combine_nodes( + self.resolve_link(new_root)?, + self.resolve_link(next_child)?, + ) + ) + } + + self.root = new_root; + + Ok(appended) + } + + #[cfg(test)] + fn for_children(&self, node: EntryLink, f: F) { + let (left, right) = { + let link = self.resolve_link(node).expect("Failed to resolve link in test"); + ( + link.left().expect("Failed to find node in test"), + link.right().expect("Failed to find node in test"), + ) + }; + f(left, right); + } + + fn pop(&mut self) { + self.stored.remove(&(self.stored_count-1)); + self.stored_count = self.stored_count - 1; + } + + /// Truncate one leaf from the end of the tree. + /// + /// Returns actual number of nodes that should be removed by the caller + /// from the end of the array representation. + pub fn truncate_leaf(&mut self) -> Result { + let root = { + let (leaves, root_left_child) = { + let n = self.resolve_link(self.root)?; + ( + n.node.leaf_count(), + n.node.left()?, + ) + }; + if leaves & 1 != 0 { + self.pop(); + self.root = root_left_child; + return Ok(1); + } else { + self.resolve_link(self.root)? + } + }; + + let mut peaks = vec![root.left()?]; + let mut subtree_root_link = root.right()?; + let mut truncated = 1; + + loop { + let left_link = self.resolve_link(subtree_root_link)?.node; + if let EntryKind::Node(left, right) = left_link.kind { + peaks.push(left); + subtree_root_link = right; + truncated += 1; + } else { + if root.node.complete() { truncated += 1; } + break; + } + } + + let mut new_root = *peaks.get(0).expect("At lest 1 elements in peaks"); + + for next_peak in peaks.into_iter().skip(1) { + new_root = self.push_generated( + combine_nodes( + self.resolve_link(new_root)?, + self.resolve_link(next_peak)?, + ) + ); + } + + for _ in 0..truncated { self.pop(); } + + self.root = new_root; + + Ok(truncated) + } + + /// Length of array representation of the tree. + pub fn len(&self) -> u32 { + self.stored_count + } + + /// Link to the root node + pub fn root(&self) -> EntryLink { self.root } + + /// Reference to the root node. + pub fn root_node(&self) -> Result { + self.resolve_link(self.root) + } + + /// If this tree is empty. + pub fn is_empty(&self) -> bool { + self.stored_count == 0 + } +} + +/// Reference to the node with link attached. +#[derive(Debug)] +pub struct IndexedNode<'a> { + node: &'a Entry, + link: EntryLink, +} + +impl<'a> IndexedNode<'a> { + + fn left(&self) -> Result { + self.node.left().map_err(|e| e.augment(self.link)) + } + + fn right(&self) -> Result { + self.node.right().map_err(|e| e.augment(self.link)) + } + + /// Reference to the entry struct. + pub fn node(&self) -> &Entry { + self.node + } + + /// Reference to the entry metadata. + pub fn data(&self) -> &NodeData { + &self.node.data + } + + /// Actual link by what this node was resolved. + pub fn link(&self) -> EntryLink { + self.link + } +} + +fn combine_nodes<'a>(left: IndexedNode<'a>, right: IndexedNode<'a>) -> Entry { + Entry { + kind: EntryKind::Node(left.link, right.link), + data: NodeData::combine(&left.node.data, &right.node.data), + } +} + +#[cfg(test)] +mod tests { + + use super::{Entry, NodeData, Tree, EntryLink, EntryKind}; + use quickcheck::{quickcheck, TestResult}; + use assert_matches::assert_matches; + + fn leaf(height: u32) -> NodeData { + NodeData { + consensus_branch_id: 1, + subtree_commitment: [0u8; 32], + start_time: 0, + end_time: 0, + start_target: 0, + end_target: 0, + start_sapling_root: [0u8; 32], + end_sapling_root: [0u8; 32], + subtree_total_work: 0.into(), + start_height: height as u64, + end_height: height as u64, + shielded_tx: 7, + } + } + + fn initial() -> Tree { + let node1: Entry = leaf(1).into(); + let node2: Entry = leaf(2).into(); + + let node3 = Entry { + data: NodeData::combine(&node1.data, &node2.data), + kind: EntryKind::Leaf, + }; + + Tree::populate(vec![node1, node2, node3], EntryLink::Stored(2)) + } + + // returns tree with specified number of leafs and it's root + fn generated(length: u32) -> Tree { + assert!(length >= 3); + let mut tree = initial(); + for i in 2..length { + tree.append_leaf(leaf(i+1).into()).expect("Failed to append"); + } + + tree + } + + #[test] + fn discrete_append() { + let mut tree = initial(); + + // ** APPEND 3 ** + let appended = tree + .append_leaf(leaf(3)) + .expect("Failed to append"); + let new_root = tree.root_node().expect("Failed to resolve root").node; + + // initial tree: (2) + // / \ + // (0) (1) + // + // new tree: + // (4g) + // / \ + // (2) \ + // / \ \ + // (0) (1) (3) + // + // so only (3) is added as real leaf + // while new root, (4g) is generated one + assert_eq!(new_root.data.end_height, 3); + assert_eq!(appended.len(), 1); + + // ** APPEND 4 ** + let appended = tree + .append_leaf(leaf(4)) + .expect("Failed to append"); + + let new_root = tree.root_node().expect("Failed to resolve root").node; + + // intermediate tree: + // (4g) + // / \ + // (2) \ + // / \ \ + // (0) (1) (3) + // + // new tree: + // ( 6 ) + // / \ + // (2) (5) + // / \ / \ + // (0) (1) (3) (4) + // + // so (4), (5), (6) are added as real leaves + // and new root, (6) is stored one + assert_eq!(new_root.data.end_height, 4); + assert_eq!(appended.len(), 3); + assert_matches!(tree.root(), EntryLink::Stored(6)); + + // ** APPEND 5 ** + + let appended = tree + .append_leaf(leaf(5)) + .expect("Failed to append"); + let new_root = tree.root_node().expect("Failed to resolve root").node; + + // intermediate tree: + // ( 6 ) + // / \ + // (2) (5) + // / \ / \ + // (0) (1) (3) (4) + // + // new tree: + // ( 8g ) + // / \ + // ( 6 ) \ + // / \ \ + // (2) (5) \ + // / \ / \ \ + // (0) (1) (3) (4) (7) + // + // so (7) is added as real leaf + // and new root, (8g) is generated one + assert_eq!(new_root.data.end_height, 5); + assert_eq!(appended.len(), 1); + assert_matches!(tree.root(), EntryLink::Generated(_)); + tree.for_children(tree.root(), |l, r| { + assert_matches!(l, EntryLink::Stored(6)); + assert_matches!(r, EntryLink::Stored(7)); + }); + + // *** APPEND #6 *** + let appended = tree + .append_leaf(leaf(6)) + .expect("Failed to append"); + let new_root = tree.root_node().expect("Failed to resolve root").node; + + // intermediate tree: + // ( 8g ) + // / \ + // ( 6 ) \ + // / \ \ + // (2) (5) \ + // / \ / \ \ + // (0) (1) (3) (4) (7) + // + // new tree: + // (---10g--) + // / \ + // ( 6 ) \ + // / \ \ + // (2) (5) (9) + // / \ / \ / \ + // (0) (1) (3) (4) (7) (8) + // + // so (7) is added as real leaf + // and new root, (10g) is generated one + assert_eq!(new_root.data.end_height, 6); + assert_eq!(appended.len(), 2); + assert_matches!(tree.root(), EntryLink::Generated(_)); + tree.for_children(tree.root(), |l, r| { + assert_matches!(l, EntryLink::Stored(6)); + assert_matches!(r, EntryLink::Stored(9)); + }); + + // *** APPEND #7 *** + + let appended = tree + .append_leaf(leaf(7)) + .expect("Failed to append"); + let new_root = tree + .root_node() + .expect("Failed to resolve root") + .node; + + // intermediate tree: + // (---8g---) + // / \ + // ( 6 ) \ + // / \ \ + // (2) (5) (9) + // / \ / \ / \ + // (0) (1) (3) (4) (7) (8) + // + // new tree: + // (---12g--) + // / \ + // (---11g---) \ + // / \ \ + // ( 6 ) \ \ + // / \ \ \ + // (2) (5) (9) \ + // / \ / \ / \ \ + // (0) (1) (3) (4) (7) (8) (10) + // + // so (10) is added as real leaf + // and new root, (12g) is generated one + assert_eq!(new_root.data.end_height, 7); + assert_eq!(appended.len(), 1); + assert_matches!(tree.root(), EntryLink::Generated(_)); + tree.for_children(tree.root(), |l, r| { + assert_matches!(l, EntryLink::Generated(_)); + tree.for_children(l, |l, r| + assert_matches!((l, r), (EntryLink::Stored(6), EntryLink::Stored(9))) + ); + assert_matches!(r, EntryLink::Stored(10)); + }); + } + + #[test] + fn truncate_simple() { + let mut tree = generated(9); + let total_truncated = tree.truncate_leaf().expect("Failed to truncate"); + + // initial tree: + // + // (-------16g------) + // / \ + // (--------14-------) \ + // / \ \ + // ( 6 ) ( 13 ) \ + // / \ / \ \ + // (2) (5) (9) (12) \ + // / \ / \ / \ / \ \ + // (0) (1) (3) (4) (7) (8) (10) (11) (15) + // + // new tree: + // (--------14-------) + // / \ + // ( 6 ) ( 13 ) + // / \ / \ + // (2) (5) (9) (12) + // / \ / \ / \ / \ + // (0) (1) (3) (4) (7) (8) (10) (11) + // + // so (15) is truncated + // and new root, (14) is a stored one now + + assert_matches!(tree.root(), EntryLink::Stored(14)); + assert_eq!(total_truncated, 1); + assert_eq!(tree.len(), 15); + } + + #[test] + fn truncate_generated() { + let mut tree = generated(10); + let deleted = tree.truncate_leaf().expect("Failed to truncate"); + + // initial tree: + // + // (--------18g--------) + // / \ + // (--------14-------) \ + // / \ \ + // ( 6 ) ( 13 ) \ + // / \ / \ \ + // (2) (5) (9) (12) (17) + // / \ / \ / \ / \ / \ + // (0) (1) (3) (4) (7) (8) (10) (11) (15) (16) + // + // new tree: + // (-------16g------) + // / \ + // (--------14-------) \ + // / \ \ + // ( 6 ) ( 13 ) \ + // / \ / \ \ + // (2) (5) (9) (12) \ + // / \ / \ / \ / \ \ + // (0) (1) (3) (4) (7) (8) (10) (11) (15) + + // new root is generated + + assert_matches!(tree.root(), EntryLink::Generated(_)); + + tree.for_children(tree.root(),|left, right| + assert_matches!( + (left, right), + (EntryLink::Stored(14), EntryLink::Stored(15)) + ) + ); + + // two stored nodes should leave us (leaf 16 and no longer needed node 17) + assert_eq!(deleted, 2); + assert_eq!(tree.len(), 16); + } + + #[test] + fn tree_len() { + let mut tree = initial(); + + assert_eq!(tree.len(), 3); + + for i in 0..2 { + tree.append_leaf(leaf(i+3)).expect("Failed to append"); + } + assert_eq!(tree.len(), 7); + + tree.truncate_leaf().expect("Failed to truncate"); + + assert_eq!(tree.len(), 4); + } + + #[test] + fn tree_len_long() { + let mut tree = initial(); + + assert_eq!(tree.len(), 3); + + for i in 0..4094 { + tree.append_leaf(leaf(i+3)).expect("Failed to append"); + } + assert_eq!(tree.len(), 8191); // 4096*2-1 (full tree) + + for _ in 0..2049 { + tree.truncate_leaf().expect("Failed to truncate"); + } + + assert_eq!(tree.len(), 4083); // 4095 - log2(4096) + } + + + quickcheck! { + fn there_and_back(number: u32) -> TestResult { + if number > 1024*1024 { + TestResult::discard() + } else { + let mut tree = initial(); + for i in 0..number { + tree.append_leaf(leaf(i+3)).expect("Failed to append"); + } + for _ in 0..number { + tree.truncate_leaf().expect("Failed to truncate"); + } + + TestResult::from_bool(if let EntryLink::Stored(2) = tree.root() { true } else { false }) + } + } + + fn leaf_count(number: u32) -> TestResult { + if number > 1024 * 1024 || number < 3 { + TestResult::discard() + } else { + let mut tree = initial(); + for i in 1..(number-1) { + tree.append_leaf(leaf(i+2)).expect("Failed to append"); + } + + TestResult::from_bool( + tree.root_node().expect("no root").node.leaf_count() == number as u64 + ) + } + } + + fn parity(number: u32) -> TestResult { + if number > 2048 * 2048 || number < 3 { + TestResult::discard() + } else { + let mut tree = initial(); + for i in 1..(number-1) { + tree.append_leaf(leaf(i+2)).expect("Failed to append"); + } + + TestResult::from_bool( + if number & (number - 1) == 0 { + if let EntryLink::Stored(_) = tree.root() { true } + else { false } + } else { + if let EntryLink::Generated(_) = tree.root() { true } + else { false } + } + ) + } + } + + fn parity_with_truncate(add: u32, delete: u32) -> TestResult { + // First we add `add` number of leaves, then delete `delete` number of leaves + // What is left should be consistent with generated-stored structure + if add > 2048 * 2048 || add < delete { + TestResult::discard() + } else { + let mut tree = initial(); + for i in 0..add { + tree.append_leaf(leaf(i+3)).expect("Failed to append"); + } + for _ in 0..delete { + tree.truncate_leaf().expect("Failed to truncate"); + } + + let total = add - delete + 2; + + TestResult::from_bool( + if total & total - 1 == 0 { + if let EntryLink::Stored(_) = tree.root() { true } + else { false } + } else { + if let EntryLink::Generated(_) = tree.root() { true } + else { false } + } + ) + } + } + + // Length of tree is always less than number of leaves squared + fn stored_length(add: u32, delete: u32) -> TestResult { + if add > 2048 * 2048 || add < delete { + TestResult::discard() + } else { + let mut tree = initial(); + for i in 0..add { + tree.append_leaf(leaf(i+3)).expect("Failed to append"); + } + for _ in 0..delete { + tree.truncate_leaf().expect("Failed to truncate"); + } + + let total = add - delete + 2; + + TestResult::from_bool(total * total > tree.len()) + } + } + } +}