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use crate::utils::hg_path::HgPath;
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use crate::utils::hg_path::HgPathBuf;
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use crate::Revision;
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use crate::NULL_REVISION;
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use im_rc::ordmap::DiffItem;
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use im_rc::ordmap::Entry;
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use im_rc::ordmap::OrdMap;
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use std::cmp::Ordering;
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use std::collections::HashMap;
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use std::convert::TryInto;
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pub type PathCopies = HashMap<HgPathBuf, HgPathBuf>;
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type PathToken = usize;
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#[derive(Clone, Debug, PartialEq, Copy)]
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struct TimeStampedPathCopy {
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/// revision at which the copy information was added
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rev: Revision,
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/// the copy source, (Set to None in case of deletion of the associated
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/// key)
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path: Option<PathToken>,
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}
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/// maps CopyDestination to Copy Source (+ a "timestamp" for the operation)
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type TimeStampedPathCopies = OrdMap<PathToken, TimeStampedPathCopy>;
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/// hold parent 1, parent 2 and relevant files actions.
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pub type RevInfo<'a> = (Revision, Revision, ChangedFiles<'a>);
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/// represent the files affected by a changesets
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///
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/// This hold a subset of mercurial.metadata.ChangingFiles as we do not need
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/// all the data categories tracked by it.
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/// This hold a subset of mercurial.metadata.ChangingFiles as we do not need
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/// all the data categories tracked by it.
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pub struct ChangedFiles<'a> {
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nb_items: u32,
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index: &'a [u8],
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data: &'a [u8],
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}
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/// Represent active changes that affect the copy tracing.
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enum Action<'a> {
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/// The parent ? children edge is removing a file
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///
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/// (actually, this could be the edge from the other parent, but it does
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/// not matters)
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Removed(&'a HgPath),
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/// The parent ? children edge introduce copy information between (dest,
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/// source)
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Copied(&'a HgPath, &'a HgPath),
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}
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/// This express the possible "special" case we can get in a merge
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///
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/// See mercurial/metadata.py for details on these values.
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#[derive(PartialEq)]
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enum MergeCase {
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/// Merged: file had history on both side that needed to be merged
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Merged,
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/// Salvaged: file was candidate for deletion, but survived the merge
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Salvaged,
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/// Normal: Not one of the two cases above
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Normal,
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}
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type FileChange<'a> = (u8, &'a HgPath, &'a HgPath);
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const EMPTY: &[u8] = b"";
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const COPY_MASK: u8 = 3;
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const P1_COPY: u8 = 2;
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const P2_COPY: u8 = 3;
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const ACTION_MASK: u8 = 28;
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const REMOVED: u8 = 12;
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const MERGED: u8 = 8;
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const SALVAGED: u8 = 16;
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impl<'a> ChangedFiles<'a> {
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const INDEX_START: usize = 4;
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const ENTRY_SIZE: u32 = 9;
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const FILENAME_START: u32 = 1;
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const COPY_SOURCE_START: u32 = 5;
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pub fn new(data: &'a [u8]) -> Self {
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assert!(
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data.len() >= 4,
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"data size ({}) is too small to contain the header (4)",
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data.len()
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);
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let nb_items_raw: [u8; 4] = (&data[0..=3])
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.try_into()
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.expect("failed to turn 4 bytes into 4 bytes");
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let nb_items = u32::from_be_bytes(nb_items_raw);
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let index_size = (nb_items * Self::ENTRY_SIZE) as usize;
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let index_end = Self::INDEX_START + index_size;
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assert!(
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data.len() >= index_end,
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"data size ({}) is too small to fit the index_data ({})",
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data.len(),
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index_end
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);
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let ret = ChangedFiles {
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nb_items,
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index: &data[Self::INDEX_START..index_end],
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data: &data[index_end..],
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};
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let max_data = ret.filename_end(nb_items - 1) as usize;
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assert!(
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ret.data.len() >= max_data,
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"data size ({}) is too small to fit all data ({})",
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data.len(),
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index_end + max_data
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);
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ret
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}
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pub fn new_empty() -> Self {
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ChangedFiles {
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nb_items: 0,
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index: EMPTY,
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data: EMPTY,
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}
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}
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/// internal function to return an individual entry at a given index
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fn entry(&'a self, idx: u32) -> FileChange<'a> {
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if idx >= self.nb_items {
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panic!(
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"index for entry is higher that the number of file {} >= {}",
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idx, self.nb_items
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)
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}
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let flags = self.flags(idx);
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let filename = self.filename(idx);
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let copy_idx = self.copy_idx(idx);
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let copy_source = self.filename(copy_idx);
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(flags, filename, copy_source)
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}
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/// internal function to return the filename of the entry at a given index
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fn filename(&self, idx: u32) -> &HgPath {
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let filename_start;
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if idx == 0 {
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filename_start = 0;
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} else {
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filename_start = self.filename_end(idx - 1)
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}
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let filename_end = self.filename_end(idx);
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let filename_start = filename_start as usize;
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let filename_end = filename_end as usize;
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HgPath::new(&self.data[filename_start..filename_end])
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}
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/// internal function to return the flag field of the entry at a given
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/// index
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fn flags(&self, idx: u32) -> u8 {
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let idx = idx as usize;
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self.index[idx * (Self::ENTRY_SIZE as usize)]
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}
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/// internal function to return the end of a filename part at a given index
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fn filename_end(&self, idx: u32) -> u32 {
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let start = (idx * Self::ENTRY_SIZE) + Self::FILENAME_START;
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let end = (idx * Self::ENTRY_SIZE) + Self::COPY_SOURCE_START;
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let start = start as usize;
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let end = end as usize;
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let raw = (&self.index[start..end])
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.try_into()
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.expect("failed to turn 4 bytes into 4 bytes");
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u32::from_be_bytes(raw)
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}
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/// internal function to return index of the copy source of the entry at a
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/// given index
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fn copy_idx(&self, idx: u32) -> u32 {
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let start = (idx * Self::ENTRY_SIZE) + Self::COPY_SOURCE_START;
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let end = (idx + 1) * Self::ENTRY_SIZE;
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let start = start as usize;
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let end = end as usize;
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let raw = (&self.index[start..end])
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.try_into()
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.expect("failed to turn 4 bytes into 4 bytes");
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u32::from_be_bytes(raw)
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}
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/// Return an iterator over all the `Action` in this instance.
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fn iter_actions(&self, parent: Parent) -> ActionsIterator {
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ActionsIterator {
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changes: &self,
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parent: parent,
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current: 0,
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}
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}
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/// return the MergeCase value associated with a filename
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fn get_merge_case(&self, path: &HgPath) -> MergeCase {
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if self.nb_items == 0 {
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return MergeCase::Normal;
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}
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let mut low_part = 0;
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let mut high_part = self.nb_items;
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while low_part < high_part {
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let cursor = (low_part + high_part - 1) / 2;
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let (flags, filename, _source) = self.entry(cursor);
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match path.cmp(filename) {
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Ordering::Less => low_part = cursor + 1,
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Ordering::Greater => high_part = cursor,
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Ordering::Equal => {
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return match flags & ACTION_MASK {
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MERGED => MergeCase::Merged,
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SALVAGED => MergeCase::Salvaged,
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_ => MergeCase::Normal,
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};
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}
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}
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}
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MergeCase::Normal
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}
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}
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/// A struct responsible for answering "is X ancestors of Y" quickly
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///
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/// The structure will delegate ancestors call to a callback, and cache the
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/// result.
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#[derive(Debug)]
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struct AncestorOracle<'a, A: Fn(Revision, Revision) -> bool> {
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inner: &'a A,
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pairs: HashMap<(Revision, Revision), bool>,
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}
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impl<'a, A: Fn(Revision, Revision) -> bool> AncestorOracle<'a, A> {
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fn new(func: &'a A) -> Self {
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Self {
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inner: func,
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pairs: HashMap::default(),
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}
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}
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fn record_overwrite(&mut self, anc: Revision, desc: Revision) {
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self.pairs.insert((anc, desc), true);
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}
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/// returns `true` if `anc` is an ancestors of `desc`, `false` otherwise
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fn is_overwrite(&mut self, anc: Revision, desc: Revision) -> bool {
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if anc > desc {
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false
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} else if anc == desc {
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true
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} else {
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if let Some(b) = self.pairs.get(&(anc, desc)) {
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*b
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} else {
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let b = (self.inner)(anc, desc);
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self.pairs.insert((anc, desc), b);
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b
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}
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}
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}
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}
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struct ActionsIterator<'a> {
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changes: &'a ChangedFiles<'a>,
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parent: Parent,
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current: u32,
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}
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impl<'a> Iterator for ActionsIterator<'a> {
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type Item = Action<'a>;
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fn next(&mut self) -> Option<Action<'a>> {
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let copy_flag = match self.parent {
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Parent::FirstParent => P1_COPY,
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Parent::SecondParent => P2_COPY,
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|
};
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while self.current < self.changes.nb_items {
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let (flags, file, source) = self.changes.entry(self.current);
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self.current += 1;
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|
if (flags & ACTION_MASK) == REMOVED {
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return Some(Action::Removed(file));
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|
}
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|
|
let copy = flags & COPY_MASK;
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|
|
if copy == copy_flag {
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|
return Some(Action::Copied(file, source));
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|
}
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|
}
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|
return None;
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|
|
}
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|
}
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|
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/// A small struct whose purpose is to ensure lifetime of bytes referenced in
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/// ChangedFiles
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///
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/// It is passed to the RevInfoMaker callback who can assign any necessary
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|
/// content to the `data` attribute. The copy tracing code is responsible for
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/// keeping the DataHolder alive at least as long as the ChangedFiles object.
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pub struct DataHolder<D> {
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|
/// RevInfoMaker callback should assign data referenced by the
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|
/// ChangedFiles struct it return to this attribute. The DataHolder
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|
|
/// lifetime will be at least as long as the ChangedFiles one.
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|
pub data: Option<D>,
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}
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pub type RevInfoMaker<'a, D> =
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Box<dyn for<'r> Fn(Revision, &'r mut DataHolder<D>) -> RevInfo<'r> + 'a>;
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|
|
/// enum used to carry information about the parent → child currently processed
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|
|
#[derive(Copy, Clone, Debug)]
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|
|
enum Parent {
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|
|
/// The `p1(x) → x` edge
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|
FirstParent,
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|
/// The `p2(x) → x` edge
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SecondParent,
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}
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|
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|
|
|
/// A small "tokenizer" responsible of turning full HgPath into lighter
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|
/// PathToken
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|
///
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|
|
/// Dealing with small object, like integer is much faster, so HgPath input are
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|
|
/// turned into integer "PathToken" and converted back in the end.
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|
|
#[derive(Clone, Debug, Default)]
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|
|
struct TwoWayPathMap {
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|
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token: HashMap<HgPathBuf, PathToken>,
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|
|
path: Vec<HgPathBuf>,
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|
|
}
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|
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impl TwoWayPathMap {
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|
|
fn tokenize(&mut self, path: &HgPath) -> PathToken {
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|
match self.token.get(path) {
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Some(a) => *a,
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|
None => {
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let a = self.token.len();
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let buf = path.to_owned();
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|
self.path.push(buf.clone());
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|
self.token.insert(buf, a);
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|
|
a
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}
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|
}
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|
}
|
|
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|
|
fn untokenize(&self, token: PathToken) -> &HgPathBuf {
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|
|
assert!(token < self.path.len(), format!("Unknown token: {}", token));
|
|
|
&self.path[token]
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|
|
}
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|
|
}
|
|
|
|
|
|
/// Same as mercurial.copies._combine_changeset_copies, but in Rust.
|
|
|
///
|
|
|
/// Arguments are:
|
|
|
///
|
|
|
/// revs: all revisions to be considered
|
|
|
/// children: a {parent ? [childrens]} mapping
|
|
|
/// target_rev: the final revision we are combining copies to
|
|
|
/// rev_info(rev): callback to get revision information:
|
|
|
/// * first parent
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|
|
/// * second parent
|
|
|
/// * ChangedFiles
|
|
|
/// isancestors(low_rev, high_rev): callback to check if a revision is an
|
|
|
/// ancestor of another
|
|
|
pub fn combine_changeset_copies<A: Fn(Revision, Revision) -> bool, D>(
|
|
|
revs: Vec<Revision>,
|
|
|
mut children_count: HashMap<Revision, usize>,
|
|
|
target_rev: Revision,
|
|
|
rev_info: RevInfoMaker<D>,
|
|
|
is_ancestor: &A,
|
|
|
) -> PathCopies {
|
|
|
let mut all_copies = HashMap::new();
|
|
|
let mut oracle = AncestorOracle::new(is_ancestor);
|
|
|
|
|
|
let mut path_map = TwoWayPathMap::default();
|
|
|
|
|
|
for rev in revs {
|
|
|
let mut d: DataHolder<D> = DataHolder { data: None };
|
|
|
let (p1, p2, changes) = rev_info(rev, &mut d);
|
|
|
|
|
|
// We will chain the copies information accumulated for the parent with
|
|
|
// the individual copies information the curent revision. Creating a
|
|
|
// new TimeStampedPath for each `rev` → `children` vertex.
|
|
|
let mut copies: Option<TimeStampedPathCopies> = None;
|
|
|
if p1 != NULL_REVISION {
|
|
|
// Retrieve data computed in a previous iteration
|
|
|
let parent_copies = get_and_clean_parent_copies(
|
|
|
&mut all_copies,
|
|
|
&mut children_count,
|
|
|
p1,
|
|
|
);
|
|
|
if let Some(parent_copies) = parent_copies {
|
|
|
// combine it with data for that revision
|
|
|
let vertex_copies = add_from_changes(
|
|
|
&mut path_map,
|
|
|
&mut oracle,
|
|
|
&parent_copies,
|
|
|
&changes,
|
|
|
Parent::FirstParent,
|
|
|
rev,
|
|
|
);
|
|
|
// keep that data around for potential later combination
|
|
|
copies = Some(vertex_copies);
|
|
|
}
|
|
|
}
|
|
|
if p2 != NULL_REVISION {
|
|
|
// Retrieve data computed in a previous iteration
|
|
|
let parent_copies = get_and_clean_parent_copies(
|
|
|
&mut all_copies,
|
|
|
&mut children_count,
|
|
|
p2,
|
|
|
);
|
|
|
if let Some(parent_copies) = parent_copies {
|
|
|
// combine it with data for that revision
|
|
|
let vertex_copies = add_from_changes(
|
|
|
&mut path_map,
|
|
|
&mut oracle,
|
|
|
&parent_copies,
|
|
|
&changes,
|
|
|
Parent::SecondParent,
|
|
|
rev,
|
|
|
);
|
|
|
|
|
|
copies = match copies {
|
|
|
None => Some(vertex_copies),
|
|
|
// Merge has two parents needs to combines their copy
|
|
|
// information.
|
|
|
//
|
|
|
// If we got data from both parents, We need to combine
|
|
|
// them.
|
|
|
Some(copies) => Some(merge_copies_dict(
|
|
|
&path_map,
|
|
|
vertex_copies,
|
|
|
copies,
|
|
|
&changes,
|
|
|
&mut oracle,
|
|
|
)),
|
|
|
};
|
|
|
}
|
|
|
}
|
|
|
match copies {
|
|
|
Some(copies) => {
|
|
|
all_copies.insert(rev, copies);
|
|
|
}
|
|
|
_ => {}
|
|
|
}
|
|
|
}
|
|
|
|
|
|
// Drop internal information (like the timestamp) and return the final
|
|
|
// mapping.
|
|
|
let tt_result = all_copies
|
|
|
.remove(&target_rev)
|
|
|
.expect("target revision was not processed");
|
|
|
let mut result = PathCopies::default();
|
|
|
for (dest, tt_source) in tt_result {
|
|
|
if let Some(path) = tt_source.path {
|
|
|
let path_dest = path_map.untokenize(dest).to_owned();
|
|
|
let path_path = path_map.untokenize(path).to_owned();
|
|
|
result.insert(path_dest, path_path);
|
|
|
}
|
|
|
}
|
|
|
result
|
|
|
}
|
|
|
|
|
|
/// fetch previous computed information
|
|
|
///
|
|
|
/// If no other children are expected to need this information, we drop it from
|
|
|
/// the cache.
|
|
|
///
|
|
|
/// If parent is not part of the set we are expected to walk, return None.
|
|
|
fn get_and_clean_parent_copies(
|
|
|
all_copies: &mut HashMap<Revision, TimeStampedPathCopies>,
|
|
|
children_count: &mut HashMap<Revision, usize>,
|
|
|
parent_rev: Revision,
|
|
|
) -> Option<TimeStampedPathCopies> {
|
|
|
let count = children_count.get_mut(&parent_rev)?;
|
|
|
*count -= 1;
|
|
|
if *count == 0 {
|
|
|
match all_copies.remove(&parent_rev) {
|
|
|
Some(c) => Some(c),
|
|
|
None => Some(TimeStampedPathCopies::default()),
|
|
|
}
|
|
|
} else {
|
|
|
match all_copies.get(&parent_rev) {
|
|
|
Some(c) => Some(c.clone()),
|
|
|
None => Some(TimeStampedPathCopies::default()),
|
|
|
}
|
|
|
}
|
|
|
}
|
|
|
|
|
|
/// Combine ChangedFiles with some existing PathCopies information and return
|
|
|
/// the result
|
|
|
fn add_from_changes<A: Fn(Revision, Revision) -> bool>(
|
|
|
path_map: &mut TwoWayPathMap,
|
|
|
oracle: &mut AncestorOracle<A>,
|
|
|
base_copies: &TimeStampedPathCopies,
|
|
|
changes: &ChangedFiles,
|
|
|
parent: Parent,
|
|
|
current_rev: Revision,
|
|
|
) -> TimeStampedPathCopies {
|
|
|
let mut copies = base_copies.clone();
|
|
|
for action in changes.iter_actions(parent) {
|
|
|
match action {
|
|
|
Action::Copied(path_dest, path_source) => {
|
|
|
let dest = path_map.tokenize(path_dest);
|
|
|
let source = path_map.tokenize(path_source);
|
|
|
let entry;
|
|
|
if let Some(v) = base_copies.get(&source) {
|
|
|
entry = match &v.path {
|
|
|
Some(path) => Some((*(path)).to_owned()),
|
|
|
None => Some(source.to_owned()),
|
|
|
}
|
|
|
} else {
|
|
|
entry = Some(source.to_owned());
|
|
|
}
|
|
|
// Each new entry is introduced by the children, we
|
|
|
// record this information as we will need it to take
|
|
|
// the right decision when merging conflicting copy
|
|
|
// information. See merge_copies_dict for details.
|
|
|
match copies.entry(dest) {
|
|
|
Entry::Vacant(slot) => {
|
|
|
let ttpc = TimeStampedPathCopy {
|
|
|
rev: current_rev,
|
|
|
path: entry,
|
|
|
};
|
|
|
slot.insert(ttpc);
|
|
|
}
|
|
|
Entry::Occupied(mut slot) => {
|
|
|
let mut ttpc = slot.get_mut();
|
|
|
oracle.record_overwrite(ttpc.rev, current_rev);
|
|
|
ttpc.rev = current_rev;
|
|
|
ttpc.path = entry;
|
|
|
}
|
|
|
}
|
|
|
}
|
|
|
Action::Removed(deleted_path) => {
|
|
|
// We must drop copy information for removed file.
|
|
|
//
|
|
|
// We need to explicitly record them as dropped to
|
|
|
// propagate this information when merging two
|
|
|
// TimeStampedPathCopies object.
|
|
|
let deleted = path_map.tokenize(deleted_path);
|
|
|
copies.entry(deleted).and_modify(|old| {
|
|
|
oracle.record_overwrite(old.rev, current_rev);
|
|
|
old.rev = current_rev;
|
|
|
old.path = None;
|
|
|
});
|
|
|
}
|
|
|
}
|
|
|
}
|
|
|
copies
|
|
|
}
|
|
|
|
|
|
/// merge two copies-mapping together, minor and major
|
|
|
///
|
|
|
/// In case of conflict, value from "major" will be picked, unless in some
|
|
|
/// cases. See inline documentation for details.
|
|
|
fn merge_copies_dict<A: Fn(Revision, Revision) -> bool>(
|
|
|
path_map: &TwoWayPathMap,
|
|
|
mut minor: TimeStampedPathCopies,
|
|
|
mut major: TimeStampedPathCopies,
|
|
|
changes: &ChangedFiles,
|
|
|
oracle: &mut AncestorOracle<A>,
|
|
|
) -> TimeStampedPathCopies {
|
|
|
// This closure exist as temporary help while multiple developper are
|
|
|
// actively working on this code. Feel free to re-inline it once this
|
|
|
// code is more settled.
|
|
|
let mut cmp_value =
|
|
|
|dest: &PathToken,
|
|
|
src_minor: &TimeStampedPathCopy,
|
|
|
src_major: &TimeStampedPathCopy| {
|
|
|
compare_value(
|
|
|
path_map, changes, oracle, dest, src_minor, src_major,
|
|
|
)
|
|
|
};
|
|
|
if minor.is_empty() {
|
|
|
major
|
|
|
} else if major.is_empty() {
|
|
|
minor
|
|
|
} else if minor.len() * 2 < major.len() {
|
|
|
// Lets says we are merging two TimeStampedPathCopies instance A and B.
|
|
|
//
|
|
|
// If A contains N items, the merge result will never contains more
|
|
|
// than N values differents than the one in A
|
|
|
//
|
|
|
// If B contains M items, with M > N, the merge result will always
|
|
|
// result in a minimum of M - N value differents than the on in
|
|
|
// A
|
|
|
//
|
|
|
// As a result, if N < (M-N), we know that simply iterating over A will
|
|
|
// yield less difference than iterating over the difference
|
|
|
// between A and B.
|
|
|
//
|
|
|
// This help performance a lot in case were a tiny
|
|
|
// TimeStampedPathCopies is merged with a much larger one.
|
|
|
for (dest, src_minor) in minor {
|
|
|
let src_major = major.get(&dest);
|
|
|
match src_major {
|
|
|
None => major.insert(dest, src_minor),
|
|
|
Some(src_major) => {
|
|
|
match cmp_value(&dest, &src_minor, src_major) {
|
|
|
MergePick::Any | MergePick::Major => None,
|
|
|
MergePick::Minor => major.insert(dest, src_minor),
|
|
|
}
|
|
|
}
|
|
|
};
|
|
|
}
|
|
|
major
|
|
|
} else if major.len() * 2 < minor.len() {
|
|
|
// This use the same rational than the previous block.
|
|
|
// (Check previous block documentation for details.)
|
|
|
for (dest, src_major) in major {
|
|
|
let src_minor = minor.get(&dest);
|
|
|
match src_minor {
|
|
|
None => minor.insert(dest, src_major),
|
|
|
Some(src_minor) => {
|
|
|
match cmp_value(&dest, src_minor, &src_major) {
|
|
|
MergePick::Any | MergePick::Minor => None,
|
|
|
MergePick::Major => minor.insert(dest, src_major),
|
|
|
}
|
|
|
}
|
|
|
};
|
|
|
}
|
|
|
minor
|
|
|
} else {
|
|
|
let mut override_minor = Vec::new();
|
|
|
let mut override_major = Vec::new();
|
|
|
|
|
|
let mut to_major = |k: &PathToken, v: &TimeStampedPathCopy| {
|
|
|
override_major.push((k.clone(), v.clone()))
|
|
|
};
|
|
|
let mut to_minor = |k: &PathToken, v: &TimeStampedPathCopy| {
|
|
|
override_minor.push((k.clone(), v.clone()))
|
|
|
};
|
|
|
|
|
|
// The diff function leverage detection of the identical subpart if
|
|
|
// minor and major has some common ancestors. This make it very
|
|
|
// fast is most case.
|
|
|
//
|
|
|
// In case where the two map are vastly different in size, the current
|
|
|
// approach is still slowish because the iteration will iterate over
|
|
|
// all the "exclusive" content of the larger on. This situation can be
|
|
|
// frequent when the subgraph of revision we are processing has a lot
|
|
|
// of roots. Each roots adding they own fully new map to the mix (and
|
|
|
// likely a small map, if the path from the root to the "main path" is
|
|
|
// small.
|
|
|
//
|
|
|
// We could do better by detecting such situation and processing them
|
|
|
// differently.
|
|
|
for d in minor.diff(&major) {
|
|
|
match d {
|
|
|
DiffItem::Add(k, v) => to_minor(k, v),
|
|
|
DiffItem::Remove(k, v) => to_major(k, v),
|
|
|
DiffItem::Update { old, new } => {
|
|
|
let (dest, src_major) = new;
|
|
|
let (_, src_minor) = old;
|
|
|
match cmp_value(dest, src_minor, src_major) {
|
|
|
MergePick::Major => to_minor(dest, src_major),
|
|
|
MergePick::Minor => to_major(dest, src_minor),
|
|
|
// If the two entry are identical, no need to do
|
|
|
// anything (but diff should not have yield them)
|
|
|
MergePick::Any => unreachable!(),
|
|
|
}
|
|
|
}
|
|
|
};
|
|
|
}
|
|
|
|
|
|
let updates;
|
|
|
let mut result;
|
|
|
if override_major.is_empty() {
|
|
|
result = major
|
|
|
} else if override_minor.is_empty() {
|
|
|
result = minor
|
|
|
} else {
|
|
|
if override_minor.len() < override_major.len() {
|
|
|
updates = override_minor;
|
|
|
result = minor;
|
|
|
} else {
|
|
|
updates = override_major;
|
|
|
result = major;
|
|
|
}
|
|
|
for (k, v) in updates {
|
|
|
result.insert(k, v);
|
|
|
}
|
|
|
}
|
|
|
result
|
|
|
}
|
|
|
}
|
|
|
|
|
|
/// represent the side that should prevail when merging two
|
|
|
/// TimeStampedPathCopies
|
|
|
enum MergePick {
|
|
|
/// The "major" (p1) side prevails
|
|
|
Major,
|
|
|
/// The "minor" (p2) side prevails
|
|
|
Minor,
|
|
|
/// Any side could be used (because they are the same)
|
|
|
Any,
|
|
|
}
|
|
|
|
|
|
/// decide which side prevails in case of conflicting values
|
|
|
#[allow(clippy::if_same_then_else)]
|
|
|
fn compare_value<A: Fn(Revision, Revision) -> bool>(
|
|
|
path_map: &TwoWayPathMap,
|
|
|
changes: &ChangedFiles,
|
|
|
oracle: &mut AncestorOracle<A>,
|
|
|
dest: &PathToken,
|
|
|
src_minor: &TimeStampedPathCopy,
|
|
|
src_major: &TimeStampedPathCopy,
|
|
|
) -> MergePick {
|
|
|
if src_major.path == src_minor.path {
|
|
|
// we have the same value, but from other source;
|
|
|
if src_major.rev == src_minor.rev {
|
|
|
// If the two entry are identical, they are both valid
|
|
|
MergePick::Any
|
|
|
} else if oracle.is_overwrite(src_major.rev, src_minor.rev) {
|
|
|
MergePick::Minor
|
|
|
} else {
|
|
|
MergePick::Major
|
|
|
}
|
|
|
} else if src_major.rev == src_minor.rev {
|
|
|
// We cannot get copy information for both p1 and p2 in the
|
|
|
// same rev. So this is the same value.
|
|
|
unreachable!(
|
|
|
"conflict information from p1 and p2 in the same revision"
|
|
|
);
|
|
|
} else {
|
|
|
let dest_path = path_map.untokenize(*dest);
|
|
|
let action = changes.get_merge_case(dest_path);
|
|
|
if src_major.path.is_none() && action == MergeCase::Salvaged {
|
|
|
// If the file is "deleted" in the major side but was
|
|
|
// salvaged by the merge, we keep the minor side alive
|
|
|
MergePick::Minor
|
|
|
} else if src_minor.path.is_none() && action == MergeCase::Salvaged {
|
|
|
// If the file is "deleted" in the minor side but was
|
|
|
// salvaged by the merge, unconditionnaly preserve the
|
|
|
// major side.
|
|
|
MergePick::Major
|
|
|
} else if action == MergeCase::Merged {
|
|
|
// If the file was actively merged, copy information
|
|
|
// from each side might conflict. The major side will
|
|
|
// win such conflict.
|
|
|
MergePick::Major
|
|
|
} else if oracle.is_overwrite(src_major.rev, src_minor.rev) {
|
|
|
// If the minor side is strictly newer than the major
|
|
|
// side, it should be kept.
|
|
|
MergePick::Minor
|
|
|
} else if src_major.path.is_some() {
|
|
|
// without any special case, the "major" value win
|
|
|
// other the "minor" one.
|
|
|
MergePick::Major
|
|
|
} else if oracle.is_overwrite(src_minor.rev, src_major.rev) {
|
|
|
// the "major" rev is a direct ancestors of "minor",
|
|
|
// any different value should
|
|
|
// overwrite
|
|
|
MergePick::Major
|
|
|
} else {
|
|
|
// major version is None (so the file was deleted on
|
|
|
// that branch) and that branch is independant (neither
|
|
|
// minor nor major is an ancestors of the other one.)
|
|
|
// We preserve the new
|
|
|
// information about the new file.
|
|
|
MergePick::Minor
|
|
|
}
|
|
|
}
|
|
|
}
|
|
|
|
