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1 | 1 | // Copyright 2018-2023 Georges Racinet <georges.racinet@octobus.net> |
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2 | 2 | // and Mercurial contributors |
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3 | 3 | // |
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4 | 4 | // This software may be used and distributed according to the terms of the |
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5 | 5 | // GNU General Public License version 2 or any later version. |
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6 | 6 | //! Mercurial concepts for handling revision history |
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7 | 7 | |
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8 | 8 | pub mod node; |
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9 | 9 | pub mod nodemap; |
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10 | 10 | mod nodemap_docket; |
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11 | 11 | pub mod path_encode; |
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12 | 12 | pub use node::{FromHexError, Node, NodePrefix}; |
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13 | 13 | pub mod changelog; |
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14 | 14 | pub mod filelog; |
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15 | 15 | pub mod index; |
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16 | 16 | pub mod manifest; |
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17 | 17 | pub mod patch; |
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18 | 18 | |
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19 | 19 | use std::borrow::Cow; |
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20 | 20 | use std::io::Read; |
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21 | 21 | use std::ops::Deref; |
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22 | 22 | use std::path::Path; |
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23 | 23 | |
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24 | 24 | use flate2::read::ZlibDecoder; |
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25 | 25 | use sha1::{Digest, Sha1}; |
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26 | 26 | use std::cell::RefCell; |
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27 | 27 | use zstd; |
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28 | 28 | |
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29 | 29 | use self::node::{NODE_BYTES_LENGTH, NULL_NODE}; |
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30 | 30 | use self::nodemap_docket::NodeMapDocket; |
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31 | 31 | use super::index::Index; |
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32 | 32 | use super::nodemap::{NodeMap, NodeMapError}; |
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33 | 33 | use crate::errors::HgError; |
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34 | 34 | use crate::vfs::Vfs; |
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35 | 35 | |
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36 | 36 | /// Mercurial revision numbers |
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37 | 37 | /// |
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38 | 38 | /// As noted in revlog.c, revision numbers are actually encoded in |
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39 | 39 | /// 4 bytes, and are liberally converted to ints, whence the i32 |
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40 | 40 | pub type Revision = i32; |
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41 | 41 | |
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42 | /// Unchecked Mercurial revision numbers. | |
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43 | /// | |
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44 | /// Values of this type have no guarantee of being a valid revision number | |
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45 | /// in any context. Use method `check_revision` to get a valid revision within | |
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46 | /// the appropriate index object. | |
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47 | /// | |
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48 | /// As noted in revlog.c, revision numbers are actually encoded in | |
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49 | /// 4 bytes, and are liberally converted to ints, whence the i32 | |
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50 | pub type UncheckedRevision = i32; | |
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51 | ||
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42 | 52 | /// Marker expressing the absence of a parent |
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43 | 53 | /// |
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44 | 54 | /// Independently of the actual representation, `NULL_REVISION` is guaranteed |
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45 | 55 | /// to be smaller than all existing revisions. |
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46 | 56 | pub const NULL_REVISION: Revision = -1; |
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47 | 57 | |
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48 | 58 | /// Same as `mercurial.node.wdirrev` |
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49 | 59 | /// |
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50 | 60 | /// This is also equal to `i32::max_value()`, but it's better to spell |
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51 | 61 | /// it out explicitely, same as in `mercurial.node` |
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52 | 62 | #[allow(clippy::unreadable_literal)] |
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53 | 63 | pub const WORKING_DIRECTORY_REVISION: Revision = 0x7fffffff; |
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54 | 64 | |
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55 | 65 | pub const WORKING_DIRECTORY_HEX: &str = |
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56 | 66 | "ffffffffffffffffffffffffffffffffffffffff"; |
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57 | 67 | |
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58 | 68 | /// The simplest expression of what we need of Mercurial DAGs. |
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59 | 69 | pub trait Graph { |
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60 | 70 | /// Return the two parents of the given `Revision`. |
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61 | 71 | /// |
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62 | 72 | /// Each of the parents can be independently `NULL_REVISION` |
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63 | 73 | fn parents(&self, rev: Revision) -> Result<[Revision; 2], GraphError>; |
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64 | 74 | } |
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65 | 75 | |
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66 | 76 | #[derive(Clone, Debug, PartialEq)] |
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67 | 77 | pub enum GraphError { |
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68 | 78 | ParentOutOfRange(Revision), |
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69 | 79 | WorkingDirectoryUnsupported, |
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70 | 80 | } |
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71 | 81 | |
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72 | 82 | /// The Mercurial Revlog Index |
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73 | 83 | /// |
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74 | 84 | /// This is currently limited to the minimal interface that is needed for |
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75 | 85 | /// the [`nodemap`](nodemap/index.html) module |
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76 | 86 | pub trait RevlogIndex { |
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77 | 87 | /// Total number of Revisions referenced in this index |
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78 | 88 | fn len(&self) -> usize; |
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79 | 89 | |
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80 | 90 | fn is_empty(&self) -> bool { |
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81 | 91 | self.len() == 0 |
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82 | 92 | } |
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83 | 93 | |
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84 | 94 | /// Return a reference to the Node or `None` if rev is out of bounds |
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85 | 95 | /// |
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86 | 96 | /// `NULL_REVISION` is not considered to be out of bounds. |
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87 | 97 | fn node(&self, rev: Revision) -> Option<&Node>; |
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98 | ||
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99 | /// Return a [`Revision`] if `rev` is a valid revision number for this | |
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100 | /// index | |
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101 | fn check_revision(&self, rev: UncheckedRevision) -> Option<Revision> { | |
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102 | if rev == NULL_REVISION || (rev >= 0 && (rev as usize) < self.len()) { | |
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103 | Some(rev) | |
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104 | } else { | |
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105 | None | |
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106 | } | |
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107 | } | |
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88 | 108 | } |
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89 | 109 | |
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90 | 110 | const REVISION_FLAG_CENSORED: u16 = 1 << 15; |
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91 | 111 | const REVISION_FLAG_ELLIPSIS: u16 = 1 << 14; |
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92 | 112 | const REVISION_FLAG_EXTSTORED: u16 = 1 << 13; |
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93 | 113 | const REVISION_FLAG_HASCOPIESINFO: u16 = 1 << 12; |
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94 | 114 | |
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95 | 115 | // Keep this in sync with REVIDX_KNOWN_FLAGS in |
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96 | 116 | // mercurial/revlogutils/flagutil.py |
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97 | 117 | const REVIDX_KNOWN_FLAGS: u16 = REVISION_FLAG_CENSORED |
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98 | 118 | | REVISION_FLAG_ELLIPSIS |
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99 | 119 | | REVISION_FLAG_EXTSTORED |
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100 | 120 | | REVISION_FLAG_HASCOPIESINFO; |
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101 | 121 | |
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102 | 122 | const NULL_REVLOG_ENTRY_FLAGS: u16 = 0; |
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103 | 123 | |
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104 | 124 | #[derive(Debug, derive_more::From)] |
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105 | 125 | pub enum RevlogError { |
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106 | 126 | InvalidRevision, |
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107 | 127 | /// Working directory is not supported |
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108 | 128 | WDirUnsupported, |
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109 | 129 | /// Found more than one entry whose ID match the requested prefix |
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110 | 130 | AmbiguousPrefix, |
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111 | 131 | #[from] |
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112 | 132 | Other(HgError), |
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113 | 133 | } |
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114 | 134 | |
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115 | 135 | impl From<NodeMapError> for RevlogError { |
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116 | 136 | fn from(error: NodeMapError) -> Self { |
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117 | 137 | match error { |
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118 | 138 | NodeMapError::MultipleResults => RevlogError::AmbiguousPrefix, |
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119 | 139 | NodeMapError::RevisionNotInIndex(rev) => RevlogError::corrupted( |
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120 | 140 | format!("nodemap point to revision {} not in index", rev), |
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121 | 141 | ), |
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122 | 142 | } |
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123 | 143 | } |
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124 | 144 | } |
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125 | 145 | |
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126 | 146 | fn corrupted<S: AsRef<str>>(context: S) -> HgError { |
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127 | 147 | HgError::corrupted(format!("corrupted revlog, {}", context.as_ref())) |
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128 | 148 | } |
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129 | 149 | |
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130 | 150 | impl RevlogError { |
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131 | 151 | fn corrupted<S: AsRef<str>>(context: S) -> Self { |
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132 | 152 | RevlogError::Other(corrupted(context)) |
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133 | 153 | } |
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134 | 154 | } |
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135 | 155 | |
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136 | 156 | /// Read only implementation of revlog. |
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137 | 157 | pub struct Revlog { |
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138 | 158 | /// When index and data are not interleaved: bytes of the revlog index. |
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139 | 159 | /// When index and data are interleaved: bytes of the revlog index and |
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140 | 160 | /// data. |
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141 | 161 | index: Index, |
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142 | 162 | /// When index and data are not interleaved: bytes of the revlog data |
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143 | 163 | data_bytes: Option<Box<dyn Deref<Target = [u8]> + Send>>, |
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144 | 164 | /// When present on disk: the persistent nodemap for this revlog |
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145 | 165 | nodemap: Option<nodemap::NodeTree>, |
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146 | 166 | } |
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147 | 167 | |
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148 | 168 | impl Revlog { |
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149 | 169 | /// Open a revlog index file. |
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150 | 170 | /// |
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151 | 171 | /// It will also open the associated data file if index and data are not |
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152 | 172 | /// interleaved. |
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153 | 173 | pub fn open( |
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154 | 174 | store_vfs: &Vfs, |
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155 | 175 | index_path: impl AsRef<Path>, |
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156 | 176 | data_path: Option<&Path>, |
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157 | 177 | use_nodemap: bool, |
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158 | 178 | ) -> Result<Self, HgError> { |
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159 | 179 | let index_path = index_path.as_ref(); |
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160 | 180 | let index = { |
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161 | 181 | match store_vfs.mmap_open_opt(&index_path)? { |
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162 | 182 | None => Index::new(Box::new(vec![])), |
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163 | 183 | Some(index_mmap) => { |
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164 | 184 | let index = Index::new(Box::new(index_mmap))?; |
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165 | 185 | Ok(index) |
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166 | 186 | } |
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167 | 187 | } |
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168 | 188 | }?; |
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169 | 189 | |
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170 | 190 | let default_data_path = index_path.with_extension("d"); |
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171 | 191 | |
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172 | 192 | // type annotation required |
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173 | 193 | // won't recognize Mmap as Deref<Target = [u8]> |
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174 | 194 | let data_bytes: Option<Box<dyn Deref<Target = [u8]> + Send>> = |
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175 | 195 | if index.is_inline() { |
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176 | 196 | None |
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177 | 197 | } else { |
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178 | 198 | let data_path = data_path.unwrap_or(&default_data_path); |
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179 | 199 | let data_mmap = store_vfs.mmap_open(data_path)?; |
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180 | 200 | Some(Box::new(data_mmap)) |
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181 | 201 | }; |
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182 | 202 | |
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183 | 203 | let nodemap = if index.is_inline() || !use_nodemap { |
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184 | 204 | None |
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185 | 205 | } else { |
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186 | 206 | NodeMapDocket::read_from_file(store_vfs, index_path)?.map( |
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187 | 207 | |(docket, data)| { |
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188 | 208 | nodemap::NodeTree::load_bytes( |
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189 | 209 | Box::new(data), |
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190 | 210 | docket.data_length, |
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191 | 211 | ) |
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192 | 212 | }, |
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193 | 213 | ) |
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194 | 214 | }; |
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195 | 215 | |
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196 | 216 | Ok(Revlog { |
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197 | 217 | index, |
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198 | 218 | data_bytes, |
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199 | 219 | nodemap, |
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200 | 220 | }) |
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201 | 221 | } |
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202 | 222 | |
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203 | 223 | /// Return number of entries of the `Revlog`. |
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204 | 224 | pub fn len(&self) -> usize { |
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205 | 225 | self.index.len() |
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206 | 226 | } |
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207 | 227 | |
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208 | 228 | /// Returns `true` if the `Revlog` has zero `entries`. |
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209 | 229 | pub fn is_empty(&self) -> bool { |
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210 | 230 | self.index.is_empty() |
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211 | 231 | } |
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212 | 232 | |
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213 | 233 | /// Returns the node ID for the given revision number, if it exists in this |
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214 | 234 | /// revlog |
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215 | 235 | pub fn node_from_rev(&self, rev: Revision) -> Option<&Node> { |
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216 | 236 | if rev == NULL_REVISION { |
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217 | 237 | return Some(&NULL_NODE); |
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218 | 238 | } |
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219 | 239 | Some(self.index.get_entry(rev)?.hash()) |
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220 | 240 | } |
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221 | 241 | |
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222 | 242 | /// Return the revision number for the given node ID, if it exists in this |
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223 | 243 | /// revlog |
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224 | 244 | pub fn rev_from_node( |
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225 | 245 | &self, |
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226 | 246 | node: NodePrefix, |
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227 | 247 | ) -> Result<Revision, RevlogError> { |
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228 | 248 | let looked_up = if let Some(nodemap) = &self.nodemap { |
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229 | 249 | nodemap |
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230 | 250 | .find_bin(&self.index, node)? |
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231 | 251 | .ok_or(RevlogError::InvalidRevision) |
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232 | 252 | } else { |
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233 | 253 | self.rev_from_node_no_persistent_nodemap(node) |
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234 | 254 | }; |
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235 | 255 | |
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236 | 256 | if node.is_prefix_of(&NULL_NODE) { |
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237 | 257 | return match looked_up { |
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238 | 258 | Ok(_) => Err(RevlogError::AmbiguousPrefix), |
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239 | 259 | Err(RevlogError::InvalidRevision) => Ok(NULL_REVISION), |
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240 | 260 | res => res, |
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241 | 261 | }; |
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242 | 262 | }; |
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243 | 263 | |
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244 | 264 | looked_up |
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245 | 265 | } |
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246 | 266 | |
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247 | 267 | /// Same as `rev_from_node`, without using a persistent nodemap |
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248 | 268 | /// |
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249 | 269 | /// This is used as fallback when a persistent nodemap is not present. |
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250 | 270 | /// This happens when the persistent-nodemap experimental feature is not |
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251 | 271 | /// enabled, or for small revlogs. |
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252 | 272 | fn rev_from_node_no_persistent_nodemap( |
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253 | 273 | &self, |
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254 | 274 | node: NodePrefix, |
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255 | 275 | ) -> Result<Revision, RevlogError> { |
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256 | 276 | // Linear scan of the revlog |
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257 | 277 | // TODO: consider building a non-persistent nodemap in memory to |
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258 | 278 | // optimize these cases. |
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259 | 279 | let mut found_by_prefix = None; |
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260 | 280 | for rev in (0..self.len() as Revision).rev() { |
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261 | 281 | let index_entry = self.index.get_entry(rev).ok_or_else(|| { |
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262 | 282 | HgError::corrupted( |
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263 | 283 | "revlog references a revision not in the index", |
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264 | 284 | ) |
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265 | 285 | })?; |
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266 | 286 | if node == *index_entry.hash() { |
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267 | 287 | return Ok(rev); |
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268 | 288 | } |
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269 | 289 | if node.is_prefix_of(index_entry.hash()) { |
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270 | 290 | if found_by_prefix.is_some() { |
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271 | 291 | return Err(RevlogError::AmbiguousPrefix); |
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272 | 292 | } |
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273 | 293 | found_by_prefix = Some(rev) |
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274 | 294 | } |
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275 | 295 | } |
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276 | 296 | found_by_prefix.ok_or(RevlogError::InvalidRevision) |
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277 | 297 | } |
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278 | 298 | |
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279 | 299 | /// Returns whether the given revision exists in this revlog. |
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280 | 300 | pub fn has_rev(&self, rev: Revision) -> bool { |
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281 | 301 | self.index.get_entry(rev).is_some() |
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282 | 302 | } |
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283 | 303 | |
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284 | 304 | /// Return the full data associated to a revision. |
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285 | 305 | /// |
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286 | 306 | /// All entries required to build the final data out of deltas will be |
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287 | 307 | /// retrieved as needed, and the deltas will be applied to the inital |
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288 | 308 | /// snapshot to rebuild the final data. |
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289 | 309 | pub fn get_rev_data( |
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290 | 310 | &self, |
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291 | 311 | rev: Revision, |
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292 | 312 | ) -> Result<Cow<[u8]>, RevlogError> { |
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293 | 313 | if rev == NULL_REVISION { |
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294 | 314 | return Ok(Cow::Borrowed(&[])); |
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295 | 315 | }; |
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296 | 316 | Ok(self.get_entry(rev)?.data()?) |
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297 | 317 | } |
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298 | 318 | |
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299 | 319 | /// Check the hash of some given data against the recorded hash. |
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300 | 320 | pub fn check_hash( |
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301 | 321 | &self, |
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302 | 322 | p1: Revision, |
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303 | 323 | p2: Revision, |
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304 | 324 | expected: &[u8], |
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305 | 325 | data: &[u8], |
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306 | 326 | ) -> bool { |
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307 | 327 | let e1 = self.index.get_entry(p1); |
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308 | 328 | let h1 = match e1 { |
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309 | 329 | Some(ref entry) => entry.hash(), |
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310 | 330 | None => &NULL_NODE, |
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311 | 331 | }; |
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312 | 332 | let e2 = self.index.get_entry(p2); |
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313 | 333 | let h2 = match e2 { |
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314 | 334 | Some(ref entry) => entry.hash(), |
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315 | 335 | None => &NULL_NODE, |
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316 | 336 | }; |
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317 | 337 | |
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318 | 338 | hash(data, h1.as_bytes(), h2.as_bytes()) == expected |
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319 | 339 | } |
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320 | 340 | |
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321 | 341 | /// Build the full data of a revision out its snapshot |
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322 | 342 | /// and its deltas. |
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323 | 343 | fn build_data_from_deltas( |
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324 | 344 | snapshot: RevlogEntry, |
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325 | 345 | deltas: &[RevlogEntry], |
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326 | 346 | ) -> Result<Vec<u8>, HgError> { |
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327 | 347 | let snapshot = snapshot.data_chunk()?; |
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328 | 348 | let deltas = deltas |
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329 | 349 | .iter() |
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330 | 350 | .rev() |
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331 | 351 | .map(RevlogEntry::data_chunk) |
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332 | 352 | .collect::<Result<Vec<_>, _>>()?; |
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333 | 353 | let patches: Vec<_> = |
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334 | 354 | deltas.iter().map(|d| patch::PatchList::new(d)).collect(); |
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335 | 355 | let patch = patch::fold_patch_lists(&patches); |
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336 | 356 | Ok(patch.apply(&snapshot)) |
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337 | 357 | } |
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338 | 358 | |
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339 | 359 | /// Return the revlog data. |
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340 | 360 | fn data(&self) -> &[u8] { |
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341 | 361 | match &self.data_bytes { |
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342 | 362 | Some(data_bytes) => data_bytes, |
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343 | 363 | None => panic!( |
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344 | 364 | "forgot to load the data or trying to access inline data" |
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345 | 365 | ), |
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346 | 366 | } |
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347 | 367 | } |
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348 | 368 | |
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349 | 369 | pub fn make_null_entry(&self) -> RevlogEntry { |
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350 | 370 | RevlogEntry { |
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351 | 371 | revlog: self, |
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352 | 372 | rev: NULL_REVISION, |
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353 | 373 | bytes: b"", |
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354 | 374 | compressed_len: 0, |
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355 | 375 | uncompressed_len: 0, |
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356 | 376 | base_rev_or_base_of_delta_chain: None, |
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357 | 377 | p1: NULL_REVISION, |
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358 | 378 | p2: NULL_REVISION, |
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359 | 379 | flags: NULL_REVLOG_ENTRY_FLAGS, |
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360 | 380 | hash: NULL_NODE, |
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361 | 381 | } |
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362 | 382 | } |
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363 | 383 | |
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364 | 384 | /// Get an entry of the revlog. |
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365 | 385 | pub fn get_entry( |
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366 | 386 | &self, |
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367 | 387 | rev: Revision, |
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368 | 388 | ) -> Result<RevlogEntry, RevlogError> { |
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369 | 389 | if rev == NULL_REVISION { |
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370 | 390 | return Ok(self.make_null_entry()); |
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371 | 391 | } |
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372 | 392 | let index_entry = self |
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373 | 393 | .index |
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374 | 394 | .get_entry(rev) |
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375 | 395 | .ok_or(RevlogError::InvalidRevision)?; |
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376 | 396 | let start = index_entry.offset(); |
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377 | 397 | let end = start + index_entry.compressed_len() as usize; |
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378 | 398 | let data = if self.index.is_inline() { |
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379 | 399 | self.index.data(start, end) |
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380 | 400 | } else { |
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381 | 401 | &self.data()[start..end] |
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382 | 402 | }; |
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383 | 403 | let entry = RevlogEntry { |
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384 | 404 | revlog: self, |
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385 | 405 | rev, |
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386 | 406 | bytes: data, |
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387 | 407 | compressed_len: index_entry.compressed_len(), |
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388 | 408 | uncompressed_len: index_entry.uncompressed_len(), |
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389 | 409 | base_rev_or_base_of_delta_chain: if index_entry |
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390 | 410 | .base_revision_or_base_of_delta_chain() |
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391 | 411 | == rev |
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392 | 412 | { |
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393 | 413 | None |
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394 | 414 | } else { |
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395 | 415 | Some(index_entry.base_revision_or_base_of_delta_chain()) |
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396 | 416 | }, |
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397 | 417 | p1: index_entry.p1(), |
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398 | 418 | p2: index_entry.p2(), |
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399 | 419 | flags: index_entry.flags(), |
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400 | 420 | hash: *index_entry.hash(), |
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401 | 421 | }; |
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402 | 422 | Ok(entry) |
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403 | 423 | } |
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404 | 424 | |
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405 | 425 | /// when resolving internal references within revlog, any errors |
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406 | 426 | /// should be reported as corruption, instead of e.g. "invalid revision" |
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407 | 427 | fn get_entry_internal( |
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408 | 428 | &self, |
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409 | 429 | rev: Revision, |
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410 | 430 | ) -> Result<RevlogEntry, HgError> { |
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411 | 431 | self.get_entry(rev) |
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412 | 432 | .map_err(|_| corrupted(format!("revision {} out of range", rev))) |
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413 | 433 | } |
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414 | 434 | } |
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415 | 435 | |
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416 | 436 | /// The revlog entry's bytes and the necessary informations to extract |
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417 | 437 | /// the entry's data. |
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418 | 438 | #[derive(Clone)] |
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419 | 439 | pub struct RevlogEntry<'revlog> { |
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420 | 440 | revlog: &'revlog Revlog, |
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421 | 441 | rev: Revision, |
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422 | 442 | bytes: &'revlog [u8], |
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423 | 443 | compressed_len: u32, |
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424 | 444 | uncompressed_len: i32, |
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425 | 445 | base_rev_or_base_of_delta_chain: Option<Revision>, |
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426 | 446 | p1: Revision, |
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427 | 447 | p2: Revision, |
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428 | 448 | flags: u16, |
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429 | 449 | hash: Node, |
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430 | 450 | } |
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431 | 451 | |
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432 | 452 | thread_local! { |
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433 | 453 | // seems fine to [unwrap] here: this can only fail due to memory allocation |
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434 | 454 | // failing, and it's normal for that to cause panic. |
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435 | 455 | static ZSTD_DECODER : RefCell<zstd::bulk::Decompressor<'static>> = |
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436 | 456 | RefCell::new(zstd::bulk::Decompressor::new().ok().unwrap()); |
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437 | 457 | } |
|
438 | 458 | |
|
439 | 459 | fn zstd_decompress_to_buffer( |
|
440 | 460 | bytes: &[u8], |
|
441 | 461 | buf: &mut Vec<u8>, |
|
442 | 462 | ) -> Result<usize, std::io::Error> { |
|
443 | 463 | ZSTD_DECODER |
|
444 | 464 | .with(|decoder| decoder.borrow_mut().decompress_to_buffer(bytes, buf)) |
|
445 | 465 | } |
|
446 | 466 | |
|
447 | 467 | impl<'revlog> RevlogEntry<'revlog> { |
|
448 | 468 | pub fn revision(&self) -> Revision { |
|
449 | 469 | self.rev |
|
450 | 470 | } |
|
451 | 471 | |
|
452 | 472 | pub fn node(&self) -> &Node { |
|
453 | 473 | &self.hash |
|
454 | 474 | } |
|
455 | 475 | |
|
456 | 476 | pub fn uncompressed_len(&self) -> Option<u32> { |
|
457 | 477 | u32::try_from(self.uncompressed_len).ok() |
|
458 | 478 | } |
|
459 | 479 | |
|
460 | 480 | pub fn has_p1(&self) -> bool { |
|
461 | 481 | self.p1 != NULL_REVISION |
|
462 | 482 | } |
|
463 | 483 | |
|
464 | 484 | pub fn p1_entry( |
|
465 | 485 | &self, |
|
466 | 486 | ) -> Result<Option<RevlogEntry<'revlog>>, RevlogError> { |
|
467 | 487 | if self.p1 == NULL_REVISION { |
|
468 | 488 | Ok(None) |
|
469 | 489 | } else { |
|
470 | 490 | Ok(Some(self.revlog.get_entry(self.p1)?)) |
|
471 | 491 | } |
|
472 | 492 | } |
|
473 | 493 | |
|
474 | 494 | pub fn p2_entry( |
|
475 | 495 | &self, |
|
476 | 496 | ) -> Result<Option<RevlogEntry<'revlog>>, RevlogError> { |
|
477 | 497 | if self.p2 == NULL_REVISION { |
|
478 | 498 | Ok(None) |
|
479 | 499 | } else { |
|
480 | 500 | Ok(Some(self.revlog.get_entry(self.p2)?)) |
|
481 | 501 | } |
|
482 | 502 | } |
|
483 | 503 | |
|
484 | 504 | pub fn p1(&self) -> Option<Revision> { |
|
485 | 505 | if self.p1 == NULL_REVISION { |
|
486 | 506 | None |
|
487 | 507 | } else { |
|
488 | 508 | Some(self.p1) |
|
489 | 509 | } |
|
490 | 510 | } |
|
491 | 511 | |
|
492 | 512 | pub fn p2(&self) -> Option<Revision> { |
|
493 | 513 | if self.p2 == NULL_REVISION { |
|
494 | 514 | None |
|
495 | 515 | } else { |
|
496 | 516 | Some(self.p2) |
|
497 | 517 | } |
|
498 | 518 | } |
|
499 | 519 | |
|
500 | 520 | pub fn is_censored(&self) -> bool { |
|
501 | 521 | (self.flags & REVISION_FLAG_CENSORED) != 0 |
|
502 | 522 | } |
|
503 | 523 | |
|
504 | 524 | pub fn has_length_affecting_flag_processor(&self) -> bool { |
|
505 | 525 | // Relevant Python code: revlog.size() |
|
506 | 526 | // note: ELLIPSIS is known to not change the content |
|
507 | 527 | (self.flags & (REVIDX_KNOWN_FLAGS ^ REVISION_FLAG_ELLIPSIS)) != 0 |
|
508 | 528 | } |
|
509 | 529 | |
|
510 | 530 | /// The data for this entry, after resolving deltas if any. |
|
511 | 531 | pub fn rawdata(&self) -> Result<Cow<'revlog, [u8]>, HgError> { |
|
512 | 532 | let mut entry = self.clone(); |
|
513 | 533 | let mut delta_chain = vec![]; |
|
514 | 534 | |
|
515 | 535 | // The meaning of `base_rev_or_base_of_delta_chain` depends on |
|
516 | 536 | // generaldelta. See the doc on `ENTRY_DELTA_BASE` in |
|
517 | 537 | // `mercurial/revlogutils/constants.py` and the code in |
|
518 | 538 | // [_chaininfo] and in [index_deltachain]. |
|
519 | 539 | let uses_generaldelta = self.revlog.index.uses_generaldelta(); |
|
520 | 540 | while let Some(base_rev) = entry.base_rev_or_base_of_delta_chain { |
|
521 | 541 | let base_rev = if uses_generaldelta { |
|
522 | 542 | base_rev |
|
523 | 543 | } else { |
|
524 | 544 | entry.rev - 1 |
|
525 | 545 | }; |
|
526 | 546 | delta_chain.push(entry); |
|
527 | 547 | entry = self.revlog.get_entry_internal(base_rev)?; |
|
528 | 548 | } |
|
529 | 549 | |
|
530 | 550 | let data = if delta_chain.is_empty() { |
|
531 | 551 | entry.data_chunk()? |
|
532 | 552 | } else { |
|
533 | 553 | Revlog::build_data_from_deltas(entry, &delta_chain)?.into() |
|
534 | 554 | }; |
|
535 | 555 | |
|
536 | 556 | Ok(data) |
|
537 | 557 | } |
|
538 | 558 | |
|
539 | 559 | fn check_data( |
|
540 | 560 | &self, |
|
541 | 561 | data: Cow<'revlog, [u8]>, |
|
542 | 562 | ) -> Result<Cow<'revlog, [u8]>, HgError> { |
|
543 | 563 | if self.revlog.check_hash( |
|
544 | 564 | self.p1, |
|
545 | 565 | self.p2, |
|
546 | 566 | self.hash.as_bytes(), |
|
547 | 567 | &data, |
|
548 | 568 | ) { |
|
549 | 569 | Ok(data) |
|
550 | 570 | } else { |
|
551 | 571 | if (self.flags & REVISION_FLAG_ELLIPSIS) != 0 { |
|
552 | 572 | return Err(HgError::unsupported( |
|
553 | 573 | "ellipsis revisions are not supported by rhg", |
|
554 | 574 | )); |
|
555 | 575 | } |
|
556 | 576 | Err(corrupted(format!( |
|
557 | 577 | "hash check failed for revision {}", |
|
558 | 578 | self.rev |
|
559 | 579 | ))) |
|
560 | 580 | } |
|
561 | 581 | } |
|
562 | 582 | |
|
563 | 583 | pub fn data(&self) -> Result<Cow<'revlog, [u8]>, HgError> { |
|
564 | 584 | let data = self.rawdata()?; |
|
565 | 585 | if self.rev == NULL_REVISION { |
|
566 | 586 | return Ok(data); |
|
567 | 587 | } |
|
568 | 588 | if self.is_censored() { |
|
569 | 589 | return Err(HgError::CensoredNodeError); |
|
570 | 590 | } |
|
571 | 591 | self.check_data(data) |
|
572 | 592 | } |
|
573 | 593 | |
|
574 | 594 | /// Extract the data contained in the entry. |
|
575 | 595 | /// This may be a delta. (See `is_delta`.) |
|
576 | 596 | fn data_chunk(&self) -> Result<Cow<'revlog, [u8]>, HgError> { |
|
577 | 597 | if self.bytes.is_empty() { |
|
578 | 598 | return Ok(Cow::Borrowed(&[])); |
|
579 | 599 | } |
|
580 | 600 | match self.bytes[0] { |
|
581 | 601 | // Revision data is the entirety of the entry, including this |
|
582 | 602 | // header. |
|
583 | 603 | b'\0' => Ok(Cow::Borrowed(self.bytes)), |
|
584 | 604 | // Raw revision data follows. |
|
585 | 605 | b'u' => Ok(Cow::Borrowed(&self.bytes[1..])), |
|
586 | 606 | // zlib (RFC 1950) data. |
|
587 | 607 | b'x' => Ok(Cow::Owned(self.uncompressed_zlib_data()?)), |
|
588 | 608 | // zstd data. |
|
589 | 609 | b'\x28' => Ok(Cow::Owned(self.uncompressed_zstd_data()?)), |
|
590 | 610 | // A proper new format should have had a repo/store requirement. |
|
591 | 611 | format_type => Err(corrupted(format!( |
|
592 | 612 | "unknown compression header '{}'", |
|
593 | 613 | format_type |
|
594 | 614 | ))), |
|
595 | 615 | } |
|
596 | 616 | } |
|
597 | 617 | |
|
598 | 618 | fn uncompressed_zlib_data(&self) -> Result<Vec<u8>, HgError> { |
|
599 | 619 | let mut decoder = ZlibDecoder::new(self.bytes); |
|
600 | 620 | if self.is_delta() { |
|
601 | 621 | let mut buf = Vec::with_capacity(self.compressed_len as usize); |
|
602 | 622 | decoder |
|
603 | 623 | .read_to_end(&mut buf) |
|
604 | 624 | .map_err(|e| corrupted(e.to_string()))?; |
|
605 | 625 | Ok(buf) |
|
606 | 626 | } else { |
|
607 | 627 | let cap = self.uncompressed_len.max(0) as usize; |
|
608 | 628 | let mut buf = vec![0; cap]; |
|
609 | 629 | decoder |
|
610 | 630 | .read_exact(&mut buf) |
|
611 | 631 | .map_err(|e| corrupted(e.to_string()))?; |
|
612 | 632 | Ok(buf) |
|
613 | 633 | } |
|
614 | 634 | } |
|
615 | 635 | |
|
616 | 636 | fn uncompressed_zstd_data(&self) -> Result<Vec<u8>, HgError> { |
|
617 | 637 | let cap = self.uncompressed_len.max(0) as usize; |
|
618 | 638 | if self.is_delta() { |
|
619 | 639 | // [cap] is usually an over-estimate of the space needed because |
|
620 | 640 | // it's the length of delta-decoded data, but we're interested |
|
621 | 641 | // in the size of the delta. |
|
622 | 642 | // This means we have to [shrink_to_fit] to avoid holding on |
|
623 | 643 | // to a large chunk of memory, but it also means we must have a |
|
624 | 644 | // fallback branch, for the case when the delta is longer than |
|
625 | 645 | // the original data (surprisingly, this does happen in practice) |
|
626 | 646 | let mut buf = Vec::with_capacity(cap); |
|
627 | 647 | match zstd_decompress_to_buffer(self.bytes, &mut buf) { |
|
628 | 648 | Ok(_) => buf.shrink_to_fit(), |
|
629 | 649 | Err(_) => { |
|
630 | 650 | buf.clear(); |
|
631 | 651 | zstd::stream::copy_decode(self.bytes, &mut buf) |
|
632 | 652 | .map_err(|e| corrupted(e.to_string()))?; |
|
633 | 653 | } |
|
634 | 654 | }; |
|
635 | 655 | Ok(buf) |
|
636 | 656 | } else { |
|
637 | 657 | let mut buf = Vec::with_capacity(cap); |
|
638 | 658 | let len = zstd_decompress_to_buffer(self.bytes, &mut buf) |
|
639 | 659 | .map_err(|e| corrupted(e.to_string()))?; |
|
640 | 660 | if len != self.uncompressed_len as usize { |
|
641 | 661 | Err(corrupted("uncompressed length does not match")) |
|
642 | 662 | } else { |
|
643 | 663 | Ok(buf) |
|
644 | 664 | } |
|
645 | 665 | } |
|
646 | 666 | } |
|
647 | 667 | |
|
648 | 668 | /// Tell if the entry is a snapshot or a delta |
|
649 | 669 | /// (influences on decompression). |
|
650 | 670 | fn is_delta(&self) -> bool { |
|
651 | 671 | self.base_rev_or_base_of_delta_chain.is_some() |
|
652 | 672 | } |
|
653 | 673 | } |
|
654 | 674 | |
|
655 | 675 | /// Calculate the hash of a revision given its data and its parents. |
|
656 | 676 | fn hash( |
|
657 | 677 | data: &[u8], |
|
658 | 678 | p1_hash: &[u8], |
|
659 | 679 | p2_hash: &[u8], |
|
660 | 680 | ) -> [u8; NODE_BYTES_LENGTH] { |
|
661 | 681 | let mut hasher = Sha1::new(); |
|
662 | 682 | let (a, b) = (p1_hash, p2_hash); |
|
663 | 683 | if a > b { |
|
664 | 684 | hasher.update(b); |
|
665 | 685 | hasher.update(a); |
|
666 | 686 | } else { |
|
667 | 687 | hasher.update(a); |
|
668 | 688 | hasher.update(b); |
|
669 | 689 | } |
|
670 | 690 | hasher.update(data); |
|
671 | 691 | *hasher.finalize().as_ref() |
|
672 | 692 | } |
|
673 | 693 | |
|
674 | 694 | #[cfg(test)] |
|
675 | 695 | mod tests { |
|
676 | 696 | use super::*; |
|
677 | 697 | use crate::index::{IndexEntryBuilder, INDEX_ENTRY_SIZE}; |
|
678 | 698 | use itertools::Itertools; |
|
679 | 699 | |
|
680 | 700 | #[test] |
|
681 | 701 | fn test_empty() { |
|
682 | 702 | let temp = tempfile::tempdir().unwrap(); |
|
683 | 703 | let vfs = Vfs { base: temp.path() }; |
|
684 | 704 | std::fs::write(temp.path().join("foo.i"), b"").unwrap(); |
|
685 | 705 | let revlog = Revlog::open(&vfs, "foo.i", None, false).unwrap(); |
|
686 | 706 | assert!(revlog.is_empty()); |
|
687 | 707 | assert_eq!(revlog.len(), 0); |
|
688 | 708 | assert!(revlog.get_entry(0).is_err()); |
|
689 | 709 | assert!(!revlog.has_rev(0)); |
|
690 | 710 | assert_eq!( |
|
691 | 711 | revlog.rev_from_node(NULL_NODE.into()).unwrap(), |
|
692 | 712 | NULL_REVISION |
|
693 | 713 | ); |
|
694 | 714 | let null_entry = revlog.get_entry(NULL_REVISION).ok().unwrap(); |
|
695 | 715 | assert_eq!(null_entry.revision(), NULL_REVISION); |
|
696 | 716 | assert!(null_entry.data().unwrap().is_empty()); |
|
697 | 717 | } |
|
698 | 718 | |
|
699 | 719 | #[test] |
|
700 | 720 | fn test_inline() { |
|
701 | 721 | let temp = tempfile::tempdir().unwrap(); |
|
702 | 722 | let vfs = Vfs { base: temp.path() }; |
|
703 | 723 | let node0 = Node::from_hex("2ed2a3912a0b24502043eae84ee4b279c18b90dd") |
|
704 | 724 | .unwrap(); |
|
705 | 725 | let node1 = Node::from_hex("b004912a8510032a0350a74daa2803dadfb00e12") |
|
706 | 726 | .unwrap(); |
|
707 | 727 | let node2 = Node::from_hex("dd6ad206e907be60927b5a3117b97dffb2590582") |
|
708 | 728 | .unwrap(); |
|
709 | 729 | let entry0_bytes = IndexEntryBuilder::new() |
|
710 | 730 | .is_first(true) |
|
711 | 731 | .with_version(1) |
|
712 | 732 | .with_inline(true) |
|
713 | 733 | .with_offset(INDEX_ENTRY_SIZE) |
|
714 | 734 | .with_node(node0) |
|
715 | 735 | .build(); |
|
716 | 736 | let entry1_bytes = IndexEntryBuilder::new() |
|
717 | 737 | .with_offset(INDEX_ENTRY_SIZE) |
|
718 | 738 | .with_node(node1) |
|
719 | 739 | .build(); |
|
720 | 740 | let entry2_bytes = IndexEntryBuilder::new() |
|
721 | 741 | .with_offset(INDEX_ENTRY_SIZE) |
|
722 | 742 | .with_p1(0) |
|
723 | 743 | .with_p2(1) |
|
724 | 744 | .with_node(node2) |
|
725 | 745 | .build(); |
|
726 | 746 | let contents = vec![entry0_bytes, entry1_bytes, entry2_bytes] |
|
727 | 747 | .into_iter() |
|
728 | 748 | .flatten() |
|
729 | 749 | .collect_vec(); |
|
730 | 750 | std::fs::write(temp.path().join("foo.i"), contents).unwrap(); |
|
731 | 751 | let revlog = Revlog::open(&vfs, "foo.i", None, false).unwrap(); |
|
732 | 752 | |
|
733 | 753 | let entry0 = revlog.get_entry(0).ok().unwrap(); |
|
734 | 754 | assert_eq!(entry0.revision(), 0); |
|
735 | 755 | assert_eq!(*entry0.node(), node0); |
|
736 | 756 | assert!(!entry0.has_p1()); |
|
737 | 757 | assert_eq!(entry0.p1(), None); |
|
738 | 758 | assert_eq!(entry0.p2(), None); |
|
739 | 759 | let p1_entry = entry0.p1_entry().unwrap(); |
|
740 | 760 | assert!(p1_entry.is_none()); |
|
741 | 761 | let p2_entry = entry0.p2_entry().unwrap(); |
|
742 | 762 | assert!(p2_entry.is_none()); |
|
743 | 763 | |
|
744 | 764 | let entry1 = revlog.get_entry(1).ok().unwrap(); |
|
745 | 765 | assert_eq!(entry1.revision(), 1); |
|
746 | 766 | assert_eq!(*entry1.node(), node1); |
|
747 | 767 | assert!(!entry1.has_p1()); |
|
748 | 768 | assert_eq!(entry1.p1(), None); |
|
749 | 769 | assert_eq!(entry1.p2(), None); |
|
750 | 770 | let p1_entry = entry1.p1_entry().unwrap(); |
|
751 | 771 | assert!(p1_entry.is_none()); |
|
752 | 772 | let p2_entry = entry1.p2_entry().unwrap(); |
|
753 | 773 | assert!(p2_entry.is_none()); |
|
754 | 774 | |
|
755 | 775 | let entry2 = revlog.get_entry(2).ok().unwrap(); |
|
756 | 776 | assert_eq!(entry2.revision(), 2); |
|
757 | 777 | assert_eq!(*entry2.node(), node2); |
|
758 | 778 | assert!(entry2.has_p1()); |
|
759 | 779 | assert_eq!(entry2.p1(), Some(0)); |
|
760 | 780 | assert_eq!(entry2.p2(), Some(1)); |
|
761 | 781 | let p1_entry = entry2.p1_entry().unwrap(); |
|
762 | 782 | assert!(p1_entry.is_some()); |
|
763 | 783 | assert_eq!(p1_entry.unwrap().revision(), 0); |
|
764 | 784 | let p2_entry = entry2.p2_entry().unwrap(); |
|
765 | 785 | assert!(p2_entry.is_some()); |
|
766 | 786 | assert_eq!(p2_entry.unwrap().revision(), 1); |
|
767 | 787 | } |
|
768 | 788 | |
|
769 | 789 | #[test] |
|
770 | 790 | fn test_nodemap() { |
|
771 | 791 | let temp = tempfile::tempdir().unwrap(); |
|
772 | 792 | let vfs = Vfs { base: temp.path() }; |
|
773 | 793 | |
|
774 | 794 | // building a revlog with a forced Node starting with zeros |
|
775 | 795 | // This is a corruption, but it does not preclude using the nodemap |
|
776 | 796 | // if we don't try and access the data |
|
777 | 797 | let node0 = Node::from_hex("00d2a3912a0b24502043eae84ee4b279c18b90dd") |
|
778 | 798 | .unwrap(); |
|
779 | 799 | let node1 = Node::from_hex("b004912a8510032a0350a74daa2803dadfb00e12") |
|
780 | 800 | .unwrap(); |
|
781 | 801 | let entry0_bytes = IndexEntryBuilder::new() |
|
782 | 802 | .is_first(true) |
|
783 | 803 | .with_version(1) |
|
784 | 804 | .with_inline(true) |
|
785 | 805 | .with_offset(INDEX_ENTRY_SIZE) |
|
786 | 806 | .with_node(node0) |
|
787 | 807 | .build(); |
|
788 | 808 | let entry1_bytes = IndexEntryBuilder::new() |
|
789 | 809 | .with_offset(INDEX_ENTRY_SIZE) |
|
790 | 810 | .with_node(node1) |
|
791 | 811 | .build(); |
|
792 | 812 | let contents = vec![entry0_bytes, entry1_bytes] |
|
793 | 813 | .into_iter() |
|
794 | 814 | .flatten() |
|
795 | 815 | .collect_vec(); |
|
796 | 816 | std::fs::write(temp.path().join("foo.i"), contents).unwrap(); |
|
797 | 817 | let revlog = Revlog::open(&vfs, "foo.i", None, false).unwrap(); |
|
798 | 818 | |
|
799 | 819 | // accessing the data shows the corruption |
|
800 | 820 | revlog.get_entry(0).unwrap().data().unwrap_err(); |
|
801 | 821 | |
|
802 | 822 | assert_eq!(revlog.rev_from_node(NULL_NODE.into()).unwrap(), -1); |
|
803 | 823 | assert_eq!(revlog.rev_from_node(node0.into()).unwrap(), 0); |
|
804 | 824 | assert_eq!(revlog.rev_from_node(node1.into()).unwrap(), 1); |
|
805 | 825 | assert_eq!( |
|
806 | 826 | revlog |
|
807 | 827 | .rev_from_node(NodePrefix::from_hex("000").unwrap()) |
|
808 | 828 | .unwrap(), |
|
809 | 829 | -1 |
|
810 | 830 | ); |
|
811 | 831 | assert_eq!( |
|
812 | 832 | revlog |
|
813 | 833 | .rev_from_node(NodePrefix::from_hex("b00").unwrap()) |
|
814 | 834 | .unwrap(), |
|
815 | 835 | 1 |
|
816 | 836 | ); |
|
817 | 837 | // RevlogError does not implement PartialEq |
|
818 | 838 | // (ultimately because io::Error does not) |
|
819 | 839 | match revlog |
|
820 | 840 | .rev_from_node(NodePrefix::from_hex("00").unwrap()) |
|
821 | 841 | .expect_err("Expected to give AmbiguousPrefix error") |
|
822 | 842 | { |
|
823 | 843 | RevlogError::AmbiguousPrefix => (), |
|
824 | 844 | e => { |
|
825 | 845 | panic!("Got another error than AmbiguousPrefix: {:?}", e); |
|
826 | 846 | } |
|
827 | 847 | }; |
|
828 | 848 | } |
|
829 | 849 | } |
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