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local_backend: use ContentHash rather than hasing protos
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Insulates identifiers from the unstable serialized form.
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@Ralith
Ralith committed Nov 12, 2022
1 parent c38a848 commit 6ed6953
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Showing 4 changed files with 105 additions and 46 deletions.
130 changes: 90 additions & 40 deletions lib/src/backend.rs
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Original file line number Diff line number Diff line change
Expand Up @@ -20,6 +20,7 @@ use std::vec::Vec;

use thiserror::Error;

use crate::content_hash::ContentHash;
use crate::repo_path::{RepoPath, RepoPathComponent};

content_hash! {
Expand Down Expand Up @@ -59,8 +60,10 @@ impl CommitId {
}
}

#[derive(PartialEq, Eq, PartialOrd, Ord, Clone, Hash)]
pub struct ChangeId(Vec<u8>);
content_hash! {
#[derive(PartialEq, Eq, PartialOrd, Ord, Clone, Hash)]
pub struct ChangeId(Vec<u8>);
}

impl Debug for ChangeId {
fn fmt(&self, f: &mut Formatter<'_>) -> Result<(), Error> {
Expand Down Expand Up @@ -94,8 +97,10 @@ impl ChangeId {
}
}

#[derive(PartialEq, Eq, PartialOrd, Ord, Clone, Hash)]
pub struct TreeId(Vec<u8>);
content_hash! {
#[derive(PartialEq, Eq, PartialOrd, Ord, Clone, Hash)]
pub struct TreeId(Vec<u8>);
}

impl Debug for TreeId {
fn fmt(&self, f: &mut Formatter<'_>) -> Result<(), Error> {
Expand Down Expand Up @@ -129,8 +134,10 @@ impl TreeId {
}
}

#[derive(PartialEq, Eq, PartialOrd, Ord, Clone, Hash)]
pub struct FileId(Vec<u8>);
content_hash! {
#[derive(PartialEq, Eq, PartialOrd, Ord, Clone, Hash)]
pub struct FileId(Vec<u8>);
}

impl Debug for FileId {
fn fmt(&self, f: &mut Formatter<'_>) -> Result<(), Error> {
Expand Down Expand Up @@ -160,8 +167,10 @@ impl FileId {
}
}

#[derive(PartialEq, Eq, PartialOrd, Ord, Clone, Hash)]
pub struct SymlinkId(Vec<u8>);
content_hash! {
#[derive(PartialEq, Eq, PartialOrd, Ord, Clone, Hash)]
pub struct SymlinkId(Vec<u8>);
}

impl Debug for SymlinkId {
fn fmt(&self, f: &mut Formatter<'_>) -> Result<(), Error> {
Expand Down Expand Up @@ -191,8 +200,10 @@ impl SymlinkId {
}
}

#[derive(PartialEq, Eq, PartialOrd, Ord, Clone, Hash)]
pub struct ConflictId(Vec<u8>);
content_hash! {
#[derive(PartialEq, Eq, PartialOrd, Ord, Clone, Hash)]
pub struct ConflictId(Vec<u8>);
}

impl Debug for ConflictId {
fn fmt(&self, f: &mut Formatter<'_>) -> Result<(), Error> {
Expand Down Expand Up @@ -256,39 +267,47 @@ impl Timestamp {
}
}

#[derive(Debug, PartialEq, Eq, Clone)]
pub struct Signature {
pub name: String,
pub email: String,
pub timestamp: Timestamp,
content_hash! {
#[derive(Debug, PartialEq, Eq, Clone)]
pub struct Signature {
pub name: String,
pub email: String,
pub timestamp: Timestamp,
}
}

#[derive(Debug, Clone)]
pub struct Commit {
pub parents: Vec<CommitId>,
pub predecessors: Vec<CommitId>,
pub root_tree: TreeId,
pub change_id: ChangeId,
pub description: String,
pub author: Signature,
pub committer: Signature,
content_hash! {
#[derive(Debug, Clone)]
pub struct Commit {
pub parents: Vec<CommitId>,
pub predecessors: Vec<CommitId>,
pub root_tree: TreeId,
pub change_id: ChangeId,
pub description: String,
pub author: Signature,
pub committer: Signature,
}
}

#[derive(Debug, PartialEq, Eq, Clone)]
pub struct ConflictPart {
// TODO: Store e.g. CommitId here too? Labels (theirs/ours/base)? Would those still be
// useful e.g. after rebasing this conflict?
pub value: TreeValue,
content_hash! {
#[derive(Debug, PartialEq, Eq, Clone)]
pub struct ConflictPart {
// TODO: Store e.g. CommitId here too? Labels (theirs/ours/base)? Would those still be
// useful e.g. after rebasing this conflict?
pub value: TreeValue,
}
}

#[derive(Default, Debug, PartialEq, Eq, Clone)]
pub struct Conflict {
// A conflict is represented by a list of positive and negative states that need to be applied.
// In a simple 3-way merge of B and C with merge base A, the conflict will be { add: [B, C],
// remove: [A] }. Also note that a conflict of the form { add: [A], remove: [] } is the
// same as non-conflict A.
pub removes: Vec<ConflictPart>,
pub adds: Vec<ConflictPart>,
content_hash! {
#[derive(Default, Debug, PartialEq, Eq, Clone)]
pub struct Conflict {
// A conflict is represented by a list of positive and negative states that need to be applied.
// In a simple 3-way merge of B and C with merge base A, the conflict will be { add: [B, C],
// remove: [A] }. Also note that a conflict of the form { add: [A], remove: [] } is the
// same as non-conflict A.
pub removes: Vec<ConflictPart>,
pub adds: Vec<ConflictPart>,
}
}

#[derive(Debug, Error, PartialEq, Eq)]
Expand All @@ -310,6 +329,35 @@ pub enum TreeValue {
Conflict(ConflictId),
}

impl ContentHash for TreeValue {
fn hash(&self, state: &mut impl digest::Update) {
use TreeValue::*;
match *self {
Normal { ref id, executable } => {
state.update(&0u32.to_le_bytes());
id.hash(state);
executable.hash(state);
}
Symlink(ref id) => {
state.update(&1u32.to_le_bytes());
id.hash(state);
}
Tree(ref id) => {
state.update(&2u32.to_le_bytes());
id.hash(state);
}
GitSubmodule(ref id) => {
state.update(&3u32.to_le_bytes());
id.hash(state);
}
Conflict(ref id) => {
state.update(&4u32.to_le_bytes());
id.hash(state);
}
}
}
}

#[derive(Debug, PartialEq, Eq, Clone)]
pub struct TreeEntry<'a> {
name: &'a RepoPathComponent,
Expand Down Expand Up @@ -344,9 +392,11 @@ impl<'a> Iterator for TreeEntriesNonRecursiveIterator<'a> {
}
}

#[derive(Default, Debug, Clone)]
pub struct Tree {
entries: BTreeMap<RepoPathComponent, TreeValue>,
content_hash! {
#[derive(Default, Debug, Clone)]
pub struct Tree {
entries: BTreeMap<RepoPathComponent, TreeValue>,
}
}

impl Tree {
Expand Down
6 changes: 6 additions & 0 deletions lib/src/content_hash.rs
View file
Original file line number Diff line number Diff line change
Expand Up @@ -16,6 +16,12 @@ pub trait ContentHash {
fn hash(&self, state: &mut impl digest::Update);
}

impl ContentHash for bool {
fn hash(&self, state: &mut impl digest::Update) {
u8::from(*self).hash(state);
}
}

impl ContentHash for u8 {
fn hash(&self, state: &mut impl digest::Update) {
state.update(&[*self]);
Expand Down
7 changes: 4 additions & 3 deletions lib/src/local_backend.rs
View file
Original file line number Diff line number Diff line change
Expand Up @@ -27,6 +27,7 @@ use crate::backend::{
ConflictId, ConflictPart, FileId, MillisSinceEpoch, Signature, SymlinkId, Timestamp, Tree,
TreeId, TreeValue,
};
use crate::content_hash::hash;
use crate::file_util::persist_content_addressed_temp_file;
use crate::repo_path::{RepoPath, RepoPathComponent};

Expand Down Expand Up @@ -197,7 +198,7 @@ impl Backend for LocalBackend {

temp_file.as_file().write_all(&proto_bytes)?;

let id = TreeId::new(Blake2b512::digest(&proto_bytes).to_vec());
let id = TreeId::new(hash::<Blake2b512>(tree).to_vec());

persist_content_addressed_temp_file(temp_file, self.tree_path(&id))?;
Ok(id)
Expand All @@ -220,7 +221,7 @@ impl Backend for LocalBackend {

temp_file.as_file().write_all(&proto_bytes)?;

let id = ConflictId::new(Blake2b512::digest(&proto_bytes).to_vec());
let id = ConflictId::new(hash::<Blake2b512>(conflict).to_vec());

persist_content_addressed_temp_file(temp_file, self.conflict_path(&id))?;
Ok(id)
Expand All @@ -247,7 +248,7 @@ impl Backend for LocalBackend {

temp_file.as_file().write_all(&proto_bytes)?;

let id = CommitId::new(Blake2b512::digest(&proto_bytes).to_vec());
let id = CommitId::new(hash::<Blake2b512>(commit).to_vec());

persist_content_addressed_temp_file(temp_file, self.commit_path(&id))?;
Ok(id)
Expand Down
8 changes: 5 additions & 3 deletions lib/src/repo_path.rs
View file
Original file line number Diff line number Diff line change
Expand Up @@ -20,9 +20,11 @@ use thiserror::Error;

use crate::file_util;

#[derive(Clone, PartialEq, Eq, PartialOrd, Ord, Debug, Hash)]
pub struct RepoPathComponent {
value: String,
content_hash! {
#[derive(Clone, PartialEq, Eq, PartialOrd, Ord, Debug, Hash)]
pub struct RepoPathComponent {
value: String,
}
}

impl RepoPathComponent {
Expand Down

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