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annotate rust/hg-core/examples/nodemap/index.rs @ 47964:796206e74b10

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rhg: Reuse manifest when checking status of multiple ambiguous files When `rhg status` cannot determine whether a file is clean based on mtime and size alone, it needs to compare its contents with those found in the parent commit. Previously, rhg would find the (same) manifest of that commit again for every such file. This is lifted out of the loop and reused. Differential Revision: https://phab.mercurial-scm.org/D11411
author Simon Sapin <simon.sapin@octobus.net>
date Mon, 13 Sep 2021 18:09:10 +0200
parents e834b79def74
children 4c5f6e95df84
Ignore whitespace changes - Everywhere: Within whitespace: At end of lines:
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1 // Copyright 2019-2020 Georges Racinet <georges.racinet@octobus.net>
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2 //
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3 // This software may be used and distributed according to the terms of the
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4 // GNU General Public License version 2 or any later version.
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5
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6 //! Minimal `RevlogIndex`, readable from standard Mercurial file format
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7 use hg::*;
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8 use memmap2::*;
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9 use std::fs::File;
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10 use std::ops::Deref;
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11 use std::path::Path;
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12 use std::slice;
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13
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14 pub struct Index {
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15 data: Box<dyn Deref<Target = [IndexEntry]> + Send>,
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16 }
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17
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18 /// A fixed sized index entry. All numbers are big endian
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19 #[repr(C)]
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20 pub struct IndexEntry {
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21 not_used_yet: [u8; 24],
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22 p1: Revision,
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23 p2: Revision,
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24 node: Node,
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25 unused_node: [u8; 12],
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26 }
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27
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28 pub const INDEX_ENTRY_SIZE: usize = 64;
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29
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30 impl IndexEntry {
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31 fn parents(&self) -> [Revision; 2] {
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32 [Revision::from_be(self.p1), Revision::from_be(self.p1)]
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33 }
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34 }
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35
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36 impl RevlogIndex for Index {
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37 fn len(&self) -> usize {
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38 self.data.len()
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39 }
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40
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41 fn node(&self, rev: Revision) -> Option<&Node> {
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42 if rev == NULL_REVISION {
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43 return None;
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44 }
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45 let i = rev as usize;
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46 if i >= self.len() {
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47 None
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48 } else {
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49 Some(&self.data[i].node)
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50 }
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51 }
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52 }
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53
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54 impl Graph for &Index {
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55 fn parents(&self, rev: Revision) -> Result<[Revision; 2], GraphError> {
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56 let [p1, p2] = (*self).data[rev as usize].parents();
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57 let len = (*self).len();
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58 if p1 < NULL_REVISION
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59 || p2 < NULL_REVISION
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60 || p1 as usize >= len
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61 || p2 as usize >= len
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62 {
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63 return Err(GraphError::ParentOutOfRange(rev));
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64 }
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65 Ok([p1, p2])
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66 }
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67 }
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68
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69 struct IndexMmap(Mmap);
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70
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71 impl Deref for IndexMmap {
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72 type Target = [IndexEntry];
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73
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74 fn deref(&self) -> &[IndexEntry] {
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75 let ptr = self.0.as_ptr() as *const IndexEntry;
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76 // Any misaligned data will be ignored.
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77 debug_assert_eq!(
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78 self.0.len() % std::mem::align_of::<IndexEntry>(),
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79 0,
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80 "Misaligned data in mmap"
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81 );
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82 unsafe { slice::from_raw_parts(ptr, self.0.len() / INDEX_ENTRY_SIZE) }
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83 }
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84 }
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85
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86 impl Index {
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87 pub fn load_mmap(path: impl AsRef<Path>) -> Self {
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88 let file = File::open(path).unwrap();
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89 let msg = "Index file is missing, or missing permission";
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90 let mmap = unsafe { MmapOptions::new().map(&file) }.expect(msg);
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91 Self {
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92 data: Box::new(IndexMmap(mmap)),
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93 }
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94 }
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95 }