1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 66 67 68 69 70 71 72 73 74 75 76 77 78 79 80 81 82 83 84 85 86 87 88 89 90 91 92 93 94 95 96 97 98 99 100 101 102 103 104 105 106 107 108 109 110 111 112 113 114 115 116 117 118 119 120 121 122 123 124 125 126 127 128 129 130 131 132 133 134 135 136 137 138 139 140 141 142 143 144 145 146 147 148 149 150 151 152 153 154 155 156 157 158 159 160 161 162 163 164 165 166 167 168 169 170 171 172 173 174 175 176 177 178 179 180 181 182 183 184 185 186 187 188 189 190 191 192 193 194 195 196 197 198 199 200 201 202 203 204 205 206 207 208 209 210 211 212 213 214 215 216 217 218 219 220 221 222 223 224 225 226 227 228 229 230 231 232 233 234 235 236 237 238 239 240 241 242 243 244 245 246 247 248 249 250 251 252 253 254 255 256 257 258 259 260 261 262 263 264 265 266 267 268 269 270 271 272 273 274 275 276 277 278 279 280 281 282 283 284 285 286 287 288 289 290 291 292 293 294 295 296 297 298 299 300 301 302 303 304 305 306 307 308 309 310 311 312 313 314 315 316 317 318 319 320 321 322 323 324 325 326 327 328 329 330 331 332 333 334 335 336 337 338 339 340 341 342 343 344 345 346 347 348 349 350 351 352 353 354 355 356 357 358 359 360 361 362 363 364 365 366 367 368 369 370 371 372 373 374 375 376 377 378 379 380 381 382 383 384 385 386 387 388 389 390 391 392 393 394 395 396 397 398 399 400 401 402 403 404 405 406 407 408 409 410 411 412 413 414 415 416 417 418 419 420 421 422 423 424 425 426 427 428 429 430 431 432 433 434 435 436 437 438 439 440 441 442 443 444 445 446 447 448 449 450 451 452 453 454 455 456 457 458 459 460 461 462 463 464 465 466 467 468 469 470 471 472 473 474 475 476 477 478 479 480 481 482 483 484 485 486 487 488 489 490 491 492 493 494 495 496 497 498 499 500 501 502 503 504 505 506 507 508 509 510 511 512 513 514 515 516
// Copyright 2021-2023 Protocol Labs
// Copyright 2019-2022 ChainSafe Systems
// SPDX-License-Identifier: Apache-2.0, MIT
use anyhow::anyhow;
use cid::multihash::Code;
use cid::Cid;
use fvm_ipld_blockstore::Blockstore;
use fvm_ipld_encoding::de::DeserializeOwned;
use fvm_ipld_encoding::ser::Serialize;
use fvm_ipld_encoding::serde::Deserialize;
use fvm_ipld_encoding::CborStore;
use itertools::sorted;
use super::ValueMut;
use crate::node::{CollapsedNode, Link};
use crate::root::version::{Version as AmtVersion, V0, V3};
use crate::root::RootImpl;
use crate::{
init_sized_vec, nodes_for_height, Error, Node, DEFAULT_BIT_WIDTH, MAX_HEIGHT, MAX_INDEX,
};
#[derive(Debug)]
#[doc(hidden)]
pub struct AmtImpl<V, BS, Ver> {
pub(super) root: RootImpl<V, Ver>,
pub(super) block_store: BS,
/// Remember the last flushed CID until it changes.
flushed_cid: Option<Cid>,
}
/// Array Mapped Trie allows for the insertion and persistence of data, serializable to a CID.
///
/// Amt is not threadsafe and can't be shared between threads.
///
/// Usage:
/// ```
/// use fvm_ipld_amt::Amt;
///
/// let db = fvm_ipld_blockstore::MemoryBlockstore::default();
/// let mut amt = Amt::new(&db);
///
/// // Insert or remove any serializable values
/// amt.set(2, "foo".to_owned()).unwrap();
/// amt.set(1, "bar".to_owned()).unwrap();
/// amt.delete(2).unwrap();
/// assert_eq!(amt.count(), 1);
/// let bar: &String = amt.get(1).unwrap().unwrap();
///
/// // Generate cid by calling flush to remove cache
/// let cid = amt.flush().unwrap();
/// ```
pub type Amt<V, BS> = AmtImpl<V, BS, V3>;
/// Legacy amt V0
pub type Amtv0<V, BS> = AmtImpl<V, BS, V0>;
impl<V: PartialEq, BS: Blockstore, Ver: PartialEq> PartialEq for AmtImpl<V, BS, Ver> {
fn eq(&self, other: &Self) -> bool {
self.root == other.root
}
}
impl<V, BS, Ver> AmtImpl<V, BS, Ver>
where
Ver: AmtVersion,
{
/// Constructor for Root AMT node
pub fn new(block_store: BS) -> Self {
Self::new_with_bit_width(block_store, DEFAULT_BIT_WIDTH)
}
/// Construct new Amt with given bit width
pub fn new_with_bit_width(block_store: BS, bit_width: u32) -> Self {
Self {
root: RootImpl::new_with_bit_width(bit_width),
block_store,
flushed_cid: None,
}
}
pub(super) fn bit_width(&self) -> u32 {
self.root.bit_width
}
/// Gets the height of the `Amt`.
pub fn height(&self) -> u32 {
self.root.height
}
/// Gets count of elements added in the `Amt`.
pub fn count(&self) -> u64 {
self.root.count
}
}
impl<V, BS, Ver> AmtImpl<V, BS, Ver>
where
Ver: AmtVersion,
BS: Blockstore,
V: Serialize,
{
/// Generates an AMT from an array of serializable objects.
///
/// This can be called with an iterator of _references_ to values to avoid copying.
pub fn new_from_iter(block_store: BS, vals: impl IntoIterator<Item = V>) -> Result<Cid, Error> {
Self::new_from_iter_with_bit_width(block_store, DEFAULT_BIT_WIDTH, vals)
}
/// Generates an AMT with the requested bitwidth from an array of serializable objects.
///
/// This can be called with an iterator of _references_ to values to avoid copying.
pub fn new_from_iter_with_bit_width(
block_store: BS,
bit_width: u32,
vals: impl IntoIterator<Item = V>,
) -> Result<Cid, Error> {
#[derive(serde::Serialize)]
#[serde(transparent)]
struct FakeDeserialize<V>(V);
impl<'de, V> Deserialize<'de> for FakeDeserialize<V> {
fn deserialize<D>(_: D) -> Result<Self, D::Error>
where
D: fvm_ipld_encoding::serde_bytes::Deserializer<'de>,
{
use serde::de::Error;
Err(D::Error::custom(
"can't deserialize when constructing an AMT from an iterator",
))
}
}
let mut t = AmtImpl::<_, BS, Ver>::new_with_bit_width(block_store, bit_width);
t.batch_set(vals.into_iter().map(FakeDeserialize))?;
t.flush()
}
}
impl<V, BS, Ver> AmtImpl<V, BS, Ver>
where
V: DeserializeOwned + Serialize,
BS: Blockstore,
Ver: AmtVersion,
{
/// Constructs an AMT with a blockstore and a Cid of the root of the AMT
pub fn load(cid: &Cid, block_store: BS) -> Result<Self, Error> {
// Load root bytes from database
let root: RootImpl<V, Ver> = block_store
.get_cbor(cid)?
.ok_or_else(|| Error::CidNotFound(cid.to_string()))?;
// Sanity check, this should never be possible.
if root.height > MAX_HEIGHT {
return Err(Error::MaxHeight(root.height, MAX_HEIGHT));
}
Ok(Self {
root,
block_store,
flushed_cid: Some(*cid),
})
}
/// Get value at index of AMT
pub fn get(&self, i: u64) -> Result<Option<&V>, Error> {
if i > MAX_INDEX {
return Err(Error::OutOfRange(i));
}
if i >= nodes_for_height(self.bit_width(), self.height() + 1) {
return Ok(None);
}
self.root
.node
.get(&self.block_store, self.height(), self.bit_width(), i)
}
/// Set value at index
pub fn set(&mut self, i: u64, val: V) -> Result<(), Error> {
if i > MAX_INDEX {
return Err(Error::OutOfRange(i));
}
while i >= nodes_for_height(self.bit_width(), self.height() + 1) {
// node at index exists
if !self.root.node.is_empty() {
// Parent node for expansion
let mut new_links: Vec<Option<Link<V>>> = init_sized_vec(self.root.bit_width);
// Take root node to be moved down
let node = std::mem::replace(&mut self.root.node, Node::empty());
// Set link to child node being expanded
new_links[0] = Some(Link::Dirty(Box::new(node)));
self.root.node = Node::Link { links: new_links };
} else {
// If first expansion is before a value inserted, convert base node to Link
self.root.node = Node::Link {
links: init_sized_vec(self.bit_width()),
};
}
// Incrememnt height after each iteration
self.root.height += 1;
}
if self
.root
.node
.set(&self.block_store, self.height(), self.bit_width(), i, val)?
.is_none()
{
self.root.count += 1;
}
// There's no equality constraint on `V` so we could check if the content changed.
self.flushed_cid = None;
Ok(())
}
/// Batch set (naive for now)
// TODO Implement more efficient batch set to not have to traverse tree and keep cache for each
pub fn batch_set(&mut self, vals: impl IntoIterator<Item = V>) -> Result<(), Error> {
for (i, val) in (0u64..).zip(vals) {
self.set(i, val)?;
}
Ok(())
}
/// Delete item from AMT at index
pub fn delete(&mut self, i: u64) -> Result<Option<V>, Error> {
if i > MAX_INDEX {
return Err(Error::OutOfRange(i));
}
if i >= nodes_for_height(self.bit_width(), self.height() + 1) {
// Index was out of range of current AMT
return Ok(None);
}
// Delete node from AMT
let deleted =
self.root
.node
.delete(&self.block_store, self.height(), self.bit_width(), i)?;
if deleted.is_none() {
return Ok(None);
}
self.flushed_cid = None;
self.root.count -= 1;
if self.root.node.is_empty() {
// Last link was removed, replace root with a leaf node and reset height.
self.root.node = Node::Leaf {
vals: init_sized_vec(self.root.bit_width),
};
self.root.height = 0;
} else {
// Handle collapsing node when the root is a link node with only one link,
// sub node can be moved up into the root.
while self.root.node.can_collapse() && self.height() > 0 {
let sub_node: Node<V> = match &mut self.root.node {
Node::Link { links, .. } => match &mut links[0] {
Some(Link::Dirty(node)) => {
*std::mem::replace(node, Box::new(Node::empty()))
}
Some(Link::Cid { cid, cache }) => {
let cache_node = std::mem::take(cache);
if let Some(sn) = cache_node.into_inner() {
*sn
} else {
// Only retrieve sub node if not found in cache
self.block_store
.get_cbor::<CollapsedNode<V>>(cid)?
.ok_or_else(|| Error::CidNotFound(cid.to_string()))?
.expand(self.root.bit_width)?
}
}
_ => unreachable!("First index checked to be Some in `can_collapse`"),
},
Node::Leaf { .. } => unreachable!("Non zero height cannot be a leaf node"),
};
self.root.node = sub_node;
self.root.height -= 1;
}
}
Ok(deleted)
}
/// Deletes multiple items from AMT
/// If `strict` is true, all indices are expected to be present, and this will
/// return an error if one is not found.
///
/// Returns true if items were deleted.
pub fn batch_delete(
&mut self,
iter: impl IntoIterator<Item = u64>,
strict: bool,
) -> Result<bool, Error> {
// TODO: optimize this
let mut modified = false;
// Iterate sorted indices. Sorted to safely optimize later.
for i in sorted(iter) {
let found = self.delete(i)?.is_some();
if strict && !found {
return Err(anyhow!("no such index {} in Amt for batch delete", i).into());
}
modified |= found;
}
Ok(modified)
}
/// flush root and return Cid used as key in block store
pub fn flush(&mut self) -> Result<Cid, Error> {
if let Some(cid) = self.flushed_cid {
return Ok(cid);
}
self.root.node.flush(&self.block_store)?;
let cid = self.block_store.put_cbor(&self.root, Code::Blake2b256)?;
self.flushed_cid = Some(cid);
Ok(cid)
}
/// Iterates over each value in the Amt and runs a function on the values.
///
/// The index in the amt is a `u64` and the value is the generic parameter `V` as defined
/// in the Amt.
///
/// # Examples
///
/// ```
/// use fvm_ipld_amt::Amt;
///
/// let store = fvm_ipld_blockstore::MemoryBlockstore::default();
///
/// let mut map: Amt<String, _> = Amt::new(&store);
/// map.set(1, "One".to_owned()).unwrap();
/// map.set(4, "Four".to_owned()).unwrap();
///
/// let mut values: Vec<(u64, String)> = Vec::new();
/// map.for_each(|i, v| {
/// values.push((i, v.clone()));
/// Ok(())
/// }).unwrap();
/// assert_eq!(&values, &[(1, "One".to_owned()), (4, "Four".to_owned())]);
/// ```
#[inline]
pub fn for_each<F>(&self, mut f: F) -> Result<(), Error>
where
F: FnMut(u64, &V) -> anyhow::Result<()>,
{
self.for_each_while(|i, x| {
f(i, x)?;
Ok(true)
})
}
/// Iterates over each value in the Amt and runs a function on the values, for as long as that
/// function keeps returning `true`.
pub fn for_each_while<F>(&self, mut f: F) -> Result<(), Error>
where
F: FnMut(u64, &V) -> anyhow::Result<bool>,
{
self.root
.node
.for_each_while(
&self.block_store,
self.height(),
self.bit_width(),
0,
&mut f,
)
.map(|_| ())
}
/// Iterates over values in the Amt and runs a function on the values.
///
/// The index in the amt is a `u64` and the value is the generic parameter `V` as defined
/// in the Amt. If `start_at` is provided traversal begins at the first index >= `start_at`,
/// otherwise it begins from the first element. If `limit` is provided, traversal will stop after
/// `limit` elements have been traversed. Returns a tuple describing the number of elements
/// iterated over and optionally the index of the next element in the AMT if more elements
/// remain.
///
/// # Examples
///
/// ```
/// use fvm_ipld_amt::Amt;
///
/// let store = fvm_ipld_blockstore::MemoryBlockstore::default();
///
/// let mut map: Amt<String, _> = Amt::new(&store);
/// map.set(1, "One".to_owned()).unwrap();
/// map.set(4, "Four".to_owned()).unwrap();
/// map.set(5, "Five".to_owned()).unwrap();
/// map.set(6, "Six".to_owned()).unwrap();
/// map.set(10, "Ten".to_owned()).unwrap();
///
/// let mut values: Vec<(u64, String)> = Vec::new();
/// let (num_traversed, next_idx) = map.for_each_ranged(Some(4), Some(3), |i, v| {
/// values.push((i, v.clone()));
/// Ok(())
/// }).unwrap();
/// assert_eq!(&values, &[(4, "Four".to_owned()), (5, "Five".to_owned()), (6, "Six".to_owned())]);
/// assert_eq!(num_traversed, 3);
/// assert_eq!(next_idx, Some(10));
/// ```
pub fn for_each_ranged<F>(
&self,
start_at: Option<u64>,
limit: Option<u64>,
mut f: F,
) -> Result<(u64, Option<u64>), Error>
where
F: FnMut(u64, &V) -> anyhow::Result<()>,
{
if let Some(start_at) = start_at {
if start_at >= nodes_for_height(self.bit_width(), self.height() + 1) {
return Ok((0, None));
}
}
let (_, num_traversed, next_index) = self.root.node.for_each_while_ranged(
&self.block_store,
start_at,
limit,
self.height(),
self.bit_width(),
0,
&mut |i, v| {
f(i, v)?;
Ok(true)
},
)?;
Ok((num_traversed, next_index))
}
/// Iterates over values in the Amt and runs a function on the values, for as long as that
/// function keeps returning true.
///
/// The index in the amt is a `u64` and the value is the generic parameter `V` as defined
/// in the Amt. If `start_at` is provided traversal begins at the first index >= `start_at`,
/// otherwise it begins from the first element. If `limit` is provided, traversal will stop after
/// `limit` elements have been traversed. Returns a tuple describing the number of elements
/// iterated over and optionally the index of the next element in the AMT if more elements
/// remain.
pub fn for_each_while_ranged<F>(
&self,
start_at: Option<u64>,
limit: Option<u64>,
mut f: F,
) -> Result<(u64, Option<u64>), Error>
where
F: FnMut(u64, &V) -> anyhow::Result<bool>,
{
if let Some(start_at) = start_at {
if start_at >= nodes_for_height(self.bit_width(), self.height() + 1) {
return Ok((0, None));
}
}
let (_, num_traversed, next_index) = self.root.node.for_each_while_ranged(
&self.block_store,
start_at,
limit,
self.height(),
self.bit_width(),
0,
&mut f,
)?;
Ok((num_traversed, next_index))
}
/// Iterates over each value in the Amt and runs a function on the values that allows modifying
/// each value.
pub fn for_each_mut<F>(&mut self, mut f: F) -> Result<(), Error>
where
F: FnMut(u64, &mut ValueMut<'_, V>) -> anyhow::Result<()>,
{
self.for_each_while_mut(|i, x| {
f(i, x)?;
Ok(true)
})
}
/// Iterates over each value in the Amt and runs a function on the values that allows modifying
/// each value, for as long as that function keeps returning `true`.
pub fn for_each_while_mut<F>(&mut self, mut f: F) -> Result<(), Error>
where
F: FnMut(u64, &mut ValueMut<'_, V>) -> anyhow::Result<bool>,
{
let (_, did_mutate) = self.root.node.for_each_while_mut(
&self.block_store,
self.height(),
self.bit_width(),
0,
&mut f,
)?;
if did_mutate {
self.flushed_cid = None;
}
Ok(())
}
}