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