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extern crate failure;
extern crate git2;
extern crate memchr;
#[macro_use]
extern crate slog;
mod owned;
mod stack;
mod commute;
use std::io::Write;
pub struct Config<'a> {
pub dry_run: bool,
pub force: bool,
pub base: Option<&'a str>,
pub logger: &'a slog::Logger,
}
pub fn run(config: &Config) -> Result<(), failure::Error> {
let repo = git2::Repository::open_from_env()?;
debug!(config.logger, "repository found"; "path" => repo.path().to_str());
let base = match config.base {
Some(commitish) => Some(repo.find_commit(repo.revparse_single(commitish)?.id())?),
None => None,
};
let mut diff_options = Some({
let mut ret = git2::DiffOptions::new();
ret.context_lines(0)
.id_abbrev(40)
.ignore_filemode(true)
.ignore_submodules(true);
ret
});
let stack: Vec<_> = {
let stack = stack::working_stack(&repo, base.as_ref(), config.logger)?;
let mut diffs = Vec::with_capacity(stack.len());
for commit in &stack {
let diff = owned::Diff::new(&repo.diff_tree_to_tree(
if commit.parents().len() == 0 {
None
} else {
Some(commit.parent(0)?.tree()?)
}.as_ref(),
Some(&commit.tree()?),
diff_options.as_mut(),
)?)?;
trace!(config.logger, "parsed commit diff";
"commit" => commit.id().to_string(),
"diff" => format!("{:?}", diff),
);
diffs.push(diff);
}
stack.into_iter().zip(diffs.into_iter()).collect()
};
let mut head_tree = repo.head()?.peel_to_tree()?;
let index =
owned::Diff::new(&repo.diff_tree_to_index(Some(&head_tree), None, diff_options.as_mut())?)?;
trace!(config.logger, "parsed index";
"index" => format!("{:?}", index),
);
let signature = repo.signature()?;
let mut head_commit = repo.head()?.peel_to_commit()?;
'patch: for index_patch in index.iter() {
'hunk: for index_hunk in &index_patch.hunks {
let mut commuted_index_hunk = index_hunk.clone();
if index_patch.status != git2::Delta::Modified {
debug!(config.logger, "skipped non-modified hunk";
"path" => String::from_utf8_lossy(index_patch.new_path.as_slice()).into_owned(),
"status" => format!("{:?}", index_patch.status),
);
continue 'patch;
}
let mut commuted_old_path = index_patch.old_path.as_slice();
debug!(config.logger, "commuting hunk";
"path" => String::from_utf8_lossy(commuted_old_path).into_owned(),
"header" => format!("-{},{} +{},{}",
commuted_index_hunk.removed.start,
commuted_index_hunk.removed.lines.len(),
commuted_index_hunk.added.start,
commuted_index_hunk.added.lines.len(),
),
);
let mut dest_commit = None;
'commit: for &(ref commit, ref diff) in &stack {
let c_logger = config.logger.new(o!(
"commit" => commit.id().to_string(),
));
let next_patch = match diff.by_new(commuted_old_path) {
Some(patch) => patch,
None => {
debug!(c_logger, "skipped commit with no path");
continue 'commit;
}
};
if next_patch.status == git2::Delta::Added {
debug!(c_logger, "found noncommutative commit by add");
dest_commit = Some(commit);
break 'commit;
}
if commuted_old_path != next_patch.old_path.as_slice() {
debug!(c_logger, "changed commute path";
"path" => String::from_utf8_lossy(&next_patch.old_path).into_owned(),
);
commuted_old_path = next_patch.old_path.as_slice();
}
commuted_index_hunk = match commute::commute_diff_before(
&commuted_index_hunk,
&next_patch.hunks,
) {
Some(hunk) => {
debug!(c_logger, "commuted hunk with commit";
"offset" => (hunk.added.start as i64) - (commuted_index_hunk.added.start as i64),
);
hunk
}
None => {
debug!(c_logger, "found noncommutative commit by conflict");
dest_commit = Some(commit);
break 'commit;
}
};
}
let dest_commit = match dest_commit {
Some(commit) => commit,
None => {
debug!(config.logger, "could not find noncommutative commit");
continue 'hunk;
}
};
if !config.dry_run {
head_tree =
apply_hunk_to_tree(&repo, &head_tree, index_hunk, &index_patch.old_path)?;
head_commit = repo.find_commit(repo.commit(
Some("HEAD"),
&signature,
&signature,
&format!("fixup! {}", dest_commit.id()),
&head_tree,
&[&head_commit],
)?)?;
info!(config.logger, "committed";
"commit" => head_commit.id().to_string(),
);
} else {
info!(config.logger, "would have committed";
"fixup" => dest_commit.id().to_string(),
"header" => format!("-{},{} +{},{}",
index_hunk.removed.start,
index_hunk.removed.lines.len(),
index_hunk.added.start,
index_hunk.added.lines.len(),
),
);
}
}
}
Ok(())
}
fn apply_hunk_to_tree<'repo>(
repo: &'repo git2::Repository,
base: &git2::Tree,
hunk: &owned::Hunk,
path: &[u8],
) -> Result<git2::Tree<'repo>, failure::Error> {
let mut treebuilder = repo.treebuilder(Some(base))?;
if let Some(slash) = path.iter().position(|&x| x == '/' as u8) {
let (first, rest) = path.split_at(slash);
let rest = &rest[1..];
let (subtree, submode) = {
let entry = treebuilder
.get(first)?
.ok_or_else(|| failure::err_msg("couldn't find tree entry in tree for path"))?;
(repo.find_tree(entry.id())?, entry.filemode())
};
let result_subtree = apply_hunk_to_tree(repo, &subtree, hunk, rest)?;
treebuilder.insert(first, result_subtree.id(), submode)?;
return Ok(repo.find_tree(treebuilder.write()?)?);
}
let (blob, mode) = {
let entry = treebuilder
.get(path)?
.ok_or_else(|| failure::err_msg("couldn't find blob entry in tree for path"))?;
(repo.find_blob(entry.id())?, entry.filemode())
};
let mut blobwriter = repo.blob_writer(None)?;
let old_content = blob.content();
let (old_start, _, _, _) = hunk.anchors();
let old_content = {
let (pre, post) = old_content.split_at(skip_past_nth(b'\n', old_content, old_start));
blobwriter.write_all(pre)?;
post
};
for line in &*hunk.added.lines {
blobwriter.write_all(line)?;
}
let old_content = &old_content[skip_past_nth(b'\n', old_content, hunk.removed.lines.len())..];
blobwriter.write_all(old_content)?;
treebuilder.insert(path, blobwriter.commit()?, mode)?;
Ok(repo.find_tree(treebuilder.write()?)?)
}
fn skip_past_nth(needle: u8, haystack: &[u8], n: usize) -> usize {
if n == 0 {
return 0;
}
memchr::Memchr::new(needle, haystack)
.fuse()
.skip(n - 1)
.next()
.map(|x| x + 1)
.unwrap_or(haystack.len())
}