jj/lib/src/local_backend.rs
Waleed Khan af55d17a25 git_backend: propagate various errors
I needed this in the course of debugging an error. Before this commit, the error looked like this:

```
Error: Unexpected error from backend: Object not found
```

After this commit, it looks like this:

```
Error: Unexpected error from backend: Object with CommitId 8f59646bc9bb6bb44b5624f1248f4a708f37003c not found: object not found - no match for id (8f59646bc9bb6bb44b5624f1248f4a708f37003c); class=Odb (9); code=NotFound (-3)
```
2023-01-02 12:28:51 -06:00

418 lines
14 KiB
Rust

// Copyright 2020 The Jujutsu Authors
//
// 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
//
// https://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.
use std::fmt::Debug;
use std::fs;
use std::fs::File;
use std::io::{Read, Write};
use std::path::{Path, PathBuf};
use blake2::{Blake2b512, Digest};
use prost::Message;
use tempfile::{NamedTempFile, PersistError};
use crate::backend::{
make_root_commit, Backend, BackendError, BackendResult, ChangeId, Commit, CommitId, Conflict,
ConflictId, ConflictPart, FileId, MillisSinceEpoch, ObjectId, Signature, SymlinkId, Timestamp,
Tree, TreeId, TreeValue,
};
use crate::content_hash::blake2b_hash;
use crate::file_util::persist_content_addressed_temp_file;
use crate::repo_path::{RepoPath, RepoPathComponent};
impl From<std::io::Error> for BackendError {
fn from(err: std::io::Error) -> Self {
BackendError::Other(err.to_string())
}
}
impl From<PersistError> for BackendError {
fn from(err: PersistError) -> Self {
BackendError::Other(err.to_string())
}
}
impl From<prost::DecodeError> for BackendError {
fn from(err: prost::DecodeError) -> Self {
BackendError::Other(err.to_string())
}
}
fn map_not_found_err(err: std::io::Error, id: &impl ObjectId) -> BackendError {
if err.kind() == std::io::ErrorKind::NotFound {
BackendError::ObjectNotFound {
object_type: id.object_type(),
hash: id.hex(),
source: Box::new(err),
}
} else {
BackendError::ReadObject {
object_type: id.object_type(),
hash: id.hex(),
source: Box::new(err),
}
}
}
#[derive(Debug)]
pub struct LocalBackend {
path: PathBuf,
root_commit_id: CommitId,
empty_tree_id: TreeId,
}
impl LocalBackend {
pub fn init(store_path: &Path) -> Self {
fs::create_dir(store_path.join("commits")).unwrap();
fs::create_dir(store_path.join("trees")).unwrap();
fs::create_dir(store_path.join("files")).unwrap();
fs::create_dir(store_path.join("symlinks")).unwrap();
fs::create_dir(store_path.join("conflicts")).unwrap();
let backend = Self::load(store_path);
let empty_tree_id = backend
.write_tree(&RepoPath::root(), &Tree::default())
.unwrap();
assert_eq!(empty_tree_id, backend.empty_tree_id);
backend
}
pub fn load(store_path: &Path) -> Self {
let root_commit_id = CommitId::from_bytes(&[0; 64]);
let empty_tree_id = TreeId::from_hex("482ae5a29fbe856c7272f2071b8b0f0359ee2d89ff392b8a900643fbd0836eccd067b8bf41909e206c90d45d6e7d8b6686b93ecaee5fe1a9060d87b672101310");
LocalBackend {
path: store_path.to_path_buf(),
root_commit_id,
empty_tree_id,
}
}
fn file_path(&self, id: &FileId) -> PathBuf {
self.path.join("files").join(id.hex())
}
fn symlink_path(&self, id: &SymlinkId) -> PathBuf {
self.path.join("symlinks").join(id.hex())
}
fn tree_path(&self, id: &TreeId) -> PathBuf {
self.path.join("trees").join(id.hex())
}
fn commit_path(&self, id: &CommitId) -> PathBuf {
self.path.join("commits").join(id.hex())
}
fn conflict_path(&self, id: &ConflictId) -> PathBuf {
self.path.join("conflicts").join(id.hex())
}
}
impl Backend for LocalBackend {
fn name(&self) -> &str {
"local"
}
fn hash_length(&self) -> usize {
64
}
fn git_repo(&self) -> Option<git2::Repository> {
None
}
fn read_file(&self, _path: &RepoPath, id: &FileId) -> BackendResult<Box<dyn Read>> {
let path = self.file_path(id);
let file = File::open(path).map_err(|err| map_not_found_err(err, id))?;
Ok(Box::new(zstd::Decoder::new(file)?))
}
fn write_file(&self, _path: &RepoPath, contents: &mut dyn Read) -> BackendResult<FileId> {
let temp_file = NamedTempFile::new_in(&self.path)?;
let mut encoder = zstd::Encoder::new(temp_file.as_file(), 0)?;
let mut hasher = Blake2b512::new();
loop {
let mut buff: Vec<u8> = Vec::with_capacity(1 << 14);
let bytes_read;
unsafe {
buff.set_len(1 << 14);
bytes_read = contents.read(&mut buff)?;
buff.set_len(bytes_read);
}
if bytes_read == 0 {
break;
}
encoder.write_all(&buff)?;
hasher.update(&buff);
}
encoder.finish()?;
let id = FileId::new(hasher.finalize().to_vec());
persist_content_addressed_temp_file(temp_file, self.file_path(&id))?;
Ok(id)
}
fn read_symlink(&self, _path: &RepoPath, id: &SymlinkId) -> Result<String, BackendError> {
let path = self.symlink_path(id);
let mut file = File::open(path).map_err(|err| map_not_found_err(err, id))?;
let mut target = String::new();
file.read_to_string(&mut target).unwrap();
Ok(target)
}
fn write_symlink(&self, _path: &RepoPath, target: &str) -> Result<SymlinkId, BackendError> {
let mut temp_file = NamedTempFile::new_in(&self.path)?;
temp_file.write_all(target.as_bytes())?;
let mut hasher = Blake2b512::new();
hasher.update(target.as_bytes());
let id = SymlinkId::new(hasher.finalize().to_vec());
persist_content_addressed_temp_file(temp_file, self.symlink_path(&id))?;
Ok(id)
}
fn root_commit_id(&self) -> &CommitId {
&self.root_commit_id
}
fn empty_tree_id(&self) -> &TreeId {
&self.empty_tree_id
}
fn read_tree(&self, _path: &RepoPath, id: &TreeId) -> BackendResult<Tree> {
let path = self.tree_path(id);
let buf = fs::read(path).map_err(|err| map_not_found_err(err, id))?;
let proto = crate::protos::store::Tree::decode(&*buf)?;
Ok(tree_from_proto(proto))
}
fn write_tree(&self, _path: &RepoPath, tree: &Tree) -> BackendResult<TreeId> {
let temp_file = NamedTempFile::new_in(&self.path)?;
let proto = tree_to_proto(tree);
temp_file.as_file().write_all(&proto.encode_to_vec())?;
let id = TreeId::new(blake2b_hash(tree).to_vec());
persist_content_addressed_temp_file(temp_file, self.tree_path(&id))?;
Ok(id)
}
fn read_conflict(&self, _path: &RepoPath, id: &ConflictId) -> BackendResult<Conflict> {
let path = self.conflict_path(id);
let buf = fs::read(path).map_err(|err| map_not_found_err(err, id))?;
let proto = crate::protos::store::Conflict::decode(&*buf)?;
Ok(conflict_from_proto(proto))
}
fn write_conflict(&self, _path: &RepoPath, conflict: &Conflict) -> BackendResult<ConflictId> {
let temp_file = NamedTempFile::new_in(&self.path)?;
let proto = conflict_to_proto(conflict);
temp_file.as_file().write_all(&proto.encode_to_vec())?;
let id = ConflictId::new(blake2b_hash(conflict).to_vec());
persist_content_addressed_temp_file(temp_file, self.conflict_path(&id))?;
Ok(id)
}
fn read_commit(&self, id: &CommitId) -> BackendResult<Commit> {
if *id == self.root_commit_id {
return Ok(make_root_commit(self.empty_tree_id.clone()));
}
let path = self.commit_path(id);
let buf = fs::read(path).map_err(|err| map_not_found_err(err, id))?;
let proto = crate::protos::store::Commit::decode(&*buf)?;
Ok(commit_from_proto(proto))
}
fn write_commit(&self, commit: &Commit) -> BackendResult<CommitId> {
let temp_file = NamedTempFile::new_in(&self.path)?;
let proto = commit_to_proto(commit);
temp_file.as_file().write_all(&proto.encode_to_vec())?;
let id = CommitId::new(blake2b_hash(commit).to_vec());
persist_content_addressed_temp_file(temp_file, self.commit_path(&id))?;
Ok(id)
}
}
pub fn commit_to_proto(commit: &Commit) -> crate::protos::store::Commit {
let mut proto = crate::protos::store::Commit::default();
for parent in &commit.parents {
proto.parents.push(parent.to_bytes());
}
for predecessor in &commit.predecessors {
proto.predecessors.push(predecessor.to_bytes());
}
proto.root_tree = commit.root_tree.to_bytes();
proto.change_id = commit.change_id.to_bytes();
proto.description = commit.description.clone();
proto.author = Some(signature_to_proto(&commit.author));
proto.committer = Some(signature_to_proto(&commit.committer));
proto
}
fn commit_from_proto(proto: crate::protos::store::Commit) -> Commit {
let parents = proto.parents.into_iter().map(CommitId::new).collect();
let predecessors = proto.predecessors.into_iter().map(CommitId::new).collect();
let root_tree = TreeId::new(proto.root_tree);
let change_id = ChangeId::new(proto.change_id);
Commit {
parents,
predecessors,
root_tree,
change_id,
description: proto.description,
author: signature_from_proto(proto.author.unwrap_or_default()),
committer: signature_from_proto(proto.committer.unwrap_or_default()),
}
}
fn tree_to_proto(tree: &Tree) -> crate::protos::store::Tree {
let mut proto = crate::protos::store::Tree::default();
for entry in tree.entries() {
proto.entries.push(crate::protos::store::tree::Entry {
name: entry.name().string(),
value: Some(tree_value_to_proto(entry.value())),
});
}
proto
}
fn tree_from_proto(proto: crate::protos::store::Tree) -> Tree {
let mut tree = Tree::default();
for proto_entry in proto.entries {
let value = tree_value_from_proto(proto_entry.value.unwrap());
tree.set(RepoPathComponent::from(proto_entry.name), value);
}
tree
}
fn tree_value_to_proto(value: &TreeValue) -> crate::protos::store::TreeValue {
let mut proto = crate::protos::store::TreeValue::default();
match value {
TreeValue::File { id, executable } => {
proto.value = Some(crate::protos::store::tree_value::Value::File(
crate::protos::store::tree_value::File {
id: id.to_bytes(),
executable: *executable,
},
));
}
TreeValue::Symlink(id) => {
proto.value = Some(crate::protos::store::tree_value::Value::SymlinkId(
id.to_bytes(),
));
}
TreeValue::GitSubmodule(_id) => {
panic!("cannot store git submodules");
}
TreeValue::Tree(id) => {
proto.value = Some(crate::protos::store::tree_value::Value::TreeId(
id.to_bytes(),
));
}
TreeValue::Conflict(id) => {
proto.value = Some(crate::protos::store::tree_value::Value::ConflictId(
id.to_bytes(),
));
}
}
proto
}
fn tree_value_from_proto(proto: crate::protos::store::TreeValue) -> TreeValue {
match proto.value.unwrap() {
crate::protos::store::tree_value::Value::TreeId(id) => TreeValue::Tree(TreeId::new(id)),
crate::protos::store::tree_value::Value::File(crate::protos::store::tree_value::File {
id,
executable,
..
}) => TreeValue::File {
id: FileId::new(id),
executable,
},
crate::protos::store::tree_value::Value::SymlinkId(id) => {
TreeValue::Symlink(SymlinkId::new(id))
}
crate::protos::store::tree_value::Value::ConflictId(id) => {
TreeValue::Conflict(ConflictId::new(id))
}
}
}
fn signature_to_proto(signature: &Signature) -> crate::protos::store::commit::Signature {
crate::protos::store::commit::Signature {
name: signature.name.clone(),
email: signature.email.clone(),
timestamp: Some(crate::protos::store::commit::Timestamp {
millis_since_epoch: signature.timestamp.timestamp.0,
tz_offset: signature.timestamp.tz_offset,
}),
}
}
fn signature_from_proto(proto: crate::protos::store::commit::Signature) -> Signature {
let timestamp = proto.timestamp.unwrap_or_default();
Signature {
name: proto.name,
email: proto.email,
timestamp: Timestamp {
timestamp: MillisSinceEpoch(timestamp.millis_since_epoch),
tz_offset: timestamp.tz_offset,
},
}
}
fn conflict_to_proto(conflict: &Conflict) -> crate::protos::store::Conflict {
let mut proto = crate::protos::store::Conflict::default();
for part in &conflict.adds {
proto.adds.push(conflict_part_to_proto(part));
}
for part in &conflict.removes {
proto.removes.push(conflict_part_to_proto(part));
}
proto
}
fn conflict_from_proto(proto: crate::protos::store::Conflict) -> Conflict {
let mut conflict = Conflict::default();
for part in proto.removes {
conflict.removes.push(conflict_part_from_proto(part))
}
for part in proto.adds {
conflict.adds.push(conflict_part_from_proto(part))
}
conflict
}
fn conflict_part_from_proto(proto: crate::protos::store::conflict::Part) -> ConflictPart {
ConflictPart {
value: tree_value_from_proto(proto.content.unwrap()),
}
}
fn conflict_part_to_proto(part: &ConflictPart) -> crate::protos::store::conflict::Part {
crate::protos::store::conflict::Part {
content: Some(tree_value_to_proto(&part.value)),
}
}