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@@ -1,412 +1,438 b'' | |||
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1 | 1 | use std::borrow::Cow; |
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2 | 2 | use std::fs::File; |
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3 | 3 | use std::io::Read; |
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4 | 4 | use std::ops::Deref; |
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5 | 5 | use std::path::Path; |
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6 | 6 | |
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7 | 7 | use byteorder::{BigEndian, ByteOrder}; |
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8 | 8 | use crypto::digest::Digest; |
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9 | 9 | use crypto::sha1::Sha1; |
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10 | 10 | use flate2::read::ZlibDecoder; |
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11 | 11 | use memmap::{Mmap, MmapOptions}; |
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12 | 12 | use micro_timer::timed; |
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13 | 13 | use zstd; |
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14 | 14 | |
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15 | 15 | use super::index::Index; |
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16 | 16 | use super::node::{NODE_BYTES_LENGTH, NULL_NODE_ID}; |
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17 | 17 | use super::patch; |
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18 | 18 | use crate::revlog::Revision; |
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19 | 19 | |
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20 | 20 | pub enum RevlogError { |
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21 | 21 | IoError(std::io::Error), |
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22 | 22 | UnsuportedVersion(u16), |
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23 | 23 | InvalidRevision, |
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24 | 24 | Corrupted, |
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25 | 25 | UnknowDataFormat(u8), |
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26 | 26 | } |
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27 | 27 | |
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28 | 28 | fn mmap_open(path: &Path) -> Result<Mmap, std::io::Error> { |
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29 | 29 | let file = File::open(path)?; |
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30 | 30 | let mmap = unsafe { MmapOptions::new().map(&file) }?; |
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31 | 31 | Ok(mmap) |
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32 | 32 | } |
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33 | 33 | |
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34 | 34 | /// Read only implementation of revlog. |
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35 | 35 | pub struct Revlog { |
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36 | 36 | /// When index and data are not interleaved: bytes of the revlog index. |
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37 | 37 | /// When index and data are interleaved: bytes of the revlog index and |
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38 | 38 | /// data. |
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39 | 39 | index_bytes: Box<dyn Deref<Target = [u8]> + Send>, |
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40 | 40 | /// When index and data are not interleaved: bytes of the revlog data |
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41 | 41 | data_bytes: Option<Box<dyn Deref<Target = [u8]> + Send>>, |
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42 | 42 | } |
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43 | 43 | |
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44 | 44 | impl Revlog { |
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45 | 45 | /// Open a revlog index file. |
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46 | 46 | /// |
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47 | 47 | /// It will also open the associated data file if index and data are not |
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48 | 48 | /// interleaved. |
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49 | 49 | #[timed] |
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50 | 50 | pub fn open(index_path: &Path) -> Result<Self, RevlogError> { |
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51 | 51 | let index_mmap = |
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52 | 52 | mmap_open(&index_path).map_err(RevlogError::IoError)?; |
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53 | 53 | |
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54 | 54 | let version = get_version(&index_mmap); |
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55 | 55 | if version != 1 { |
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56 | 56 | return Err(RevlogError::UnsuportedVersion(version)); |
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57 | 57 | } |
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58 | 58 | |
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59 | 59 | let is_inline = is_inline(&index_mmap); |
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60 | 60 | |
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61 | 61 | let index_bytes = Box::new(index_mmap); |
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62 | 62 | |
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63 | 63 | // TODO load data only when needed // |
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64 | 64 | // type annotation required |
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65 | 65 | // won't recognize Mmap as Deref<Target = [u8]> |
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66 | 66 | let data_bytes: Option<Box<dyn Deref<Target = [u8]> + Send>> = |
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67 | 67 | if is_inline { |
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68 | 68 | None |
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69 | 69 | } else { |
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70 | 70 | let data_path = index_path.with_extension("d"); |
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71 | 71 | let data_mmap = |
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72 | 72 | mmap_open(&data_path).map_err(RevlogError::IoError)?; |
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73 | 73 | Some(Box::new(data_mmap)) |
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74 | 74 | }; |
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75 | 75 | |
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76 | 76 | Ok(Revlog { |
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77 | 77 | index_bytes, |
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78 | 78 | data_bytes, |
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79 | 79 | }) |
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80 | 80 | } |
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81 | 81 | |
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82 | /// Return number of entries of the `Revlog`. | |
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83 | pub fn len(&self) -> usize { | |
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84 | self.index().len() | |
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85 | } | |
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86 | ||
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87 | /// Returns `true` if the `Revlog` has zero `entries`. | |
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88 | pub fn is_empty(&self) -> bool { | |
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89 | self.index().is_empty() | |
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90 | } | |
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91 | ||
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92 | /// Return the full data associated to a node. | |
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93 | #[timed] | |
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94 | pub fn get_node_rev(&self, node: &[u8]) -> Result<Revision, RevlogError> { | |
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95 | let index = self.index(); | |
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96 | // This is brute force. But it is fast enough for now. | |
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97 | // Optimization will come later. | |
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98 | for rev in (0..self.len() as Revision).rev() { | |
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99 | let index_entry = | |
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100 | index.get_entry(rev).ok_or(RevlogError::Corrupted)?; | |
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101 | if node == index_entry.hash() { | |
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102 | return Ok(rev); | |
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103 | } | |
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104 | } | |
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105 | Err(RevlogError::InvalidRevision) | |
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106 | } | |
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107 | ||
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82 | 108 | /// Return the full data associated to a revision. |
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83 | 109 | /// |
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84 | 110 | /// All entries required to build the final data out of deltas will be |
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85 | 111 | /// retrieved as needed, and the deltas will be applied to the inital |
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86 | 112 | /// snapshot to rebuild the final data. |
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87 | 113 | #[timed] |
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88 | 114 | pub fn get_rev_data(&self, rev: Revision) -> Result<Vec<u8>, RevlogError> { |
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89 | 115 | // Todo return -> Cow |
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90 | 116 | let mut entry = self.get_entry(rev)?; |
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91 | 117 | let mut delta_chain = vec![]; |
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92 | 118 | while let Some(base_rev) = entry.base_rev { |
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93 | 119 | delta_chain.push(entry); |
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94 | 120 | entry = self |
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95 | 121 | .get_entry(base_rev) |
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96 | 122 | .map_err(|_| RevlogError::Corrupted)?; |
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97 | 123 | } |
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98 | 124 | |
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99 | 125 | // TODO do not look twice in the index |
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100 | 126 | let index = self.index(); |
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101 | 127 | let index_entry = |
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102 | 128 | index.get_entry(rev).ok_or(RevlogError::InvalidRevision)?; |
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103 | 129 | |
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104 | 130 | let data: Vec<u8> = if delta_chain.is_empty() { |
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105 | 131 | entry.data()?.into() |
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106 | 132 | } else { |
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107 | 133 | Revlog::build_data_from_deltas(entry, &delta_chain)? |
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108 | 134 | }; |
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109 | 135 | |
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110 | 136 | if self.check_hash( |
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111 | 137 | index_entry.p1(), |
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112 | 138 | index_entry.p2(), |
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113 | 139 | index_entry.hash(), |
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114 | 140 | &data, |
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115 | 141 | ) { |
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116 | 142 | Ok(data) |
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117 | 143 | } else { |
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118 | 144 | Err(RevlogError::Corrupted) |
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119 | 145 | } |
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120 | 146 | } |
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121 | 147 | |
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122 | 148 | /// Check the hash of some given data against the recorded hash. |
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123 | 149 | pub fn check_hash( |
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124 | 150 | &self, |
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125 | 151 | p1: Revision, |
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126 | 152 | p2: Revision, |
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127 | 153 | expected: &[u8], |
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128 | 154 | data: &[u8], |
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129 | 155 | ) -> bool { |
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130 | 156 | let index = self.index(); |
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131 | 157 | let e1 = index.get_entry(p1); |
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132 | 158 | let h1 = match e1 { |
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133 | 159 | Some(ref entry) => entry.hash(), |
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134 | 160 | None => &NULL_NODE_ID, |
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135 | 161 | }; |
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136 | 162 | let e2 = index.get_entry(p2); |
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137 | 163 | let h2 = match e2 { |
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138 | 164 | Some(ref entry) => entry.hash(), |
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139 | 165 | None => &NULL_NODE_ID, |
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140 | 166 | }; |
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141 | 167 | |
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142 | 168 | hash(data, &h1, &h2).as_slice() == expected |
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143 | 169 | } |
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144 | 170 | |
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145 | 171 | /// Build the full data of a revision out its snapshot |
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146 | 172 | /// and its deltas. |
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147 | 173 | #[timed] |
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148 | 174 | fn build_data_from_deltas( |
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149 | 175 | snapshot: RevlogEntry, |
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150 | 176 | deltas: &[RevlogEntry], |
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151 | 177 | ) -> Result<Vec<u8>, RevlogError> { |
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152 | 178 | let snapshot = snapshot.data()?; |
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153 | 179 | let deltas = deltas |
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154 | 180 | .iter() |
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155 | 181 | .rev() |
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156 | 182 | .map(RevlogEntry::data) |
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157 | 183 | .collect::<Result<Vec<Cow<'_, [u8]>>, RevlogError>>()?; |
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158 | 184 | let patches: Vec<_> = |
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159 | 185 | deltas.iter().map(|d| patch::PatchList::new(d)).collect(); |
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160 | 186 | let patch = patch::fold_patch_lists(&patches); |
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161 | 187 | Ok(patch.apply(&snapshot)) |
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162 | 188 | } |
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163 | 189 | |
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164 | 190 | /// Return the revlog index. |
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165 | 191 | fn index(&self) -> Index { |
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166 | 192 | let is_inline = self.data_bytes.is_none(); |
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167 | 193 | Index::new(&self.index_bytes, is_inline) |
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168 | 194 | } |
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169 | 195 | |
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170 | 196 | /// Return the revlog data. |
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171 | 197 | fn data(&self) -> &[u8] { |
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172 | 198 | match self.data_bytes { |
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173 | 199 | Some(ref data_bytes) => &data_bytes, |
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174 | 200 | None => &self.index_bytes, |
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175 | 201 | } |
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176 | 202 | } |
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177 | 203 | |
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178 | 204 | /// Get an entry of the revlog. |
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179 | 205 | fn get_entry(&self, rev: Revision) -> Result<RevlogEntry, RevlogError> { |
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180 | 206 | let index = self.index(); |
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181 | 207 | let index_entry = |
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182 | 208 | index.get_entry(rev).ok_or(RevlogError::InvalidRevision)?; |
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183 | 209 | let start = index_entry.offset(); |
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184 | 210 | let end = start + index_entry.compressed_len(); |
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185 | 211 | let entry = RevlogEntry { |
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186 | 212 | rev, |
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187 | 213 | bytes: &self.data()[start..end], |
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188 | 214 | compressed_len: index_entry.compressed_len(), |
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189 | 215 | uncompressed_len: index_entry.uncompressed_len(), |
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190 | 216 | base_rev: if index_entry.base_revision() == rev { |
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191 | 217 | None |
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192 | 218 | } else { |
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193 | 219 | Some(index_entry.base_revision()) |
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194 | 220 | }, |
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195 | 221 | }; |
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196 | 222 | Ok(entry) |
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197 | 223 | } |
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198 | 224 | } |
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199 | 225 | |
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200 | 226 | /// The revlog entry's bytes and the necessary informations to extract |
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201 | 227 | /// the entry's data. |
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202 | 228 | #[derive(Debug)] |
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203 | 229 | pub struct RevlogEntry<'a> { |
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204 | 230 | rev: Revision, |
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205 | 231 | bytes: &'a [u8], |
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206 | 232 | compressed_len: usize, |
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207 | 233 | uncompressed_len: usize, |
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208 | 234 | base_rev: Option<Revision>, |
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209 | 235 | } |
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210 | 236 | |
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211 | 237 | impl<'a> RevlogEntry<'a> { |
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212 | 238 | /// Extract the data contained in the entry. |
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213 | 239 | pub fn data(&self) -> Result<Cow<'_, [u8]>, RevlogError> { |
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214 | 240 | if self.bytes.is_empty() { |
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215 | 241 | return Ok(Cow::Borrowed(&[])); |
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216 | 242 | } |
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217 | 243 | match self.bytes[0] { |
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218 | 244 | // Revision data is the entirety of the entry, including this |
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219 | 245 | // header. |
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220 | 246 | b'\0' => Ok(Cow::Borrowed(self.bytes)), |
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221 | 247 | // Raw revision data follows. |
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222 | 248 | b'u' => Ok(Cow::Borrowed(&self.bytes[1..])), |
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223 | 249 | // zlib (RFC 1950) data. |
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224 | 250 | b'x' => Ok(Cow::Owned(self.uncompressed_zlib_data())), |
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225 | 251 | // zstd data. |
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226 | 252 | b'\x28' => Ok(Cow::Owned(self.uncompressed_zstd_data())), |
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227 | 253 | format_type => Err(RevlogError::UnknowDataFormat(format_type)), |
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228 | 254 | } |
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229 | 255 | } |
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230 | 256 | |
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231 | 257 | fn uncompressed_zlib_data(&self) -> Vec<u8> { |
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232 | 258 | let mut decoder = ZlibDecoder::new(self.bytes); |
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233 | 259 | if self.is_delta() { |
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234 | 260 | let mut buf = Vec::with_capacity(self.compressed_len); |
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235 | 261 | decoder.read_to_end(&mut buf).expect("corrupted zlib data"); |
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236 | 262 | buf |
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237 | 263 | } else { |
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238 | 264 | let mut buf = vec![0; self.uncompressed_len]; |
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239 | 265 | decoder.read_exact(&mut buf).expect("corrupted zlib data"); |
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240 | 266 | buf |
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241 | 267 | } |
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242 | 268 | } |
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243 | 269 | |
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244 | 270 | fn uncompressed_zstd_data(&self) -> Vec<u8> { |
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245 | 271 | if self.is_delta() { |
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246 | 272 | let mut buf = Vec::with_capacity(self.compressed_len); |
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247 | 273 | zstd::stream::copy_decode(self.bytes, &mut buf) |
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248 | 274 | .expect("corrupted zstd data"); |
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249 | 275 | buf |
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250 | 276 | } else { |
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251 | 277 | let mut buf = vec![0; self.uncompressed_len]; |
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252 | 278 | let len = zstd::block::decompress_to_buffer(self.bytes, &mut buf) |
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253 | 279 | .expect("corrupted zstd data"); |
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254 | 280 | assert_eq!(len, self.uncompressed_len, "corrupted zstd data"); |
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255 | 281 | buf |
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256 | 282 | } |
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257 | 283 | } |
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258 | 284 | |
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259 | 285 | /// Tell if the entry is a snapshot or a delta |
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260 | 286 | /// (influences on decompression). |
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261 | 287 | fn is_delta(&self) -> bool { |
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262 | 288 | self.base_rev.is_some() |
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263 | 289 | } |
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264 | 290 | } |
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265 | 291 | |
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266 | 292 | /// Value of the inline flag. |
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267 | 293 | pub fn is_inline(index_bytes: &[u8]) -> bool { |
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268 | 294 | match &index_bytes[0..=1] { |
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269 | 295 | [0, 0] | [0, 2] => false, |
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270 | 296 | _ => true, |
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271 | 297 | } |
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272 | 298 | } |
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273 | 299 | |
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274 | 300 | /// Format version of the revlog. |
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275 | 301 | pub fn get_version(index_bytes: &[u8]) -> u16 { |
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276 | 302 | BigEndian::read_u16(&index_bytes[2..=3]) |
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277 | 303 | } |
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278 | 304 | |
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279 | 305 | /// Calculate the hash of a revision given its data and its parents. |
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280 | 306 | fn hash(data: &[u8], p1_hash: &[u8], p2_hash: &[u8]) -> Vec<u8> { |
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281 | 307 | let mut hasher = Sha1::new(); |
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282 | 308 | let (a, b) = (p1_hash, p2_hash); |
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283 | 309 | if a > b { |
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284 | 310 | hasher.input(b); |
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285 | 311 | hasher.input(a); |
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286 | 312 | } else { |
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287 | 313 | hasher.input(a); |
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288 | 314 | hasher.input(b); |
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289 | 315 | } |
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290 | 316 | hasher.input(data); |
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291 | 317 | let mut hash = vec![0; NODE_BYTES_LENGTH]; |
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292 | 318 | hasher.result(&mut hash); |
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293 | 319 | hash |
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294 | 320 | } |
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295 | 321 | |
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296 | 322 | #[cfg(test)] |
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297 | 323 | mod tests { |
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298 | 324 | use super::*; |
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299 | 325 | |
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300 | 326 | use super::super::index::IndexEntryBuilder; |
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301 | 327 | |
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302 | 328 | #[cfg(test)] |
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303 | 329 | pub struct RevlogBuilder { |
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304 | 330 | version: u16, |
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305 | 331 | is_general_delta: bool, |
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306 | 332 | is_inline: bool, |
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307 | 333 | offset: usize, |
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308 | 334 | index: Vec<Vec<u8>>, |
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309 | 335 | data: Vec<Vec<u8>>, |
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310 | 336 | } |
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311 | 337 | |
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312 | 338 | #[cfg(test)] |
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313 | 339 | impl RevlogBuilder { |
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314 | 340 | pub fn new() -> Self { |
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315 | 341 | Self { |
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316 | 342 | version: 2, |
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317 | 343 | is_inline: false, |
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318 | 344 | is_general_delta: true, |
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319 | 345 | offset: 0, |
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320 | 346 | index: vec![], |
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321 | 347 | data: vec![], |
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322 | 348 | } |
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323 | 349 | } |
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324 | 350 | |
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325 | 351 | pub fn with_inline(&mut self, value: bool) -> &mut Self { |
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326 | 352 | self.is_inline = value; |
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327 | 353 | self |
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328 | 354 | } |
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329 | 355 | |
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330 | 356 | pub fn with_general_delta(&mut self, value: bool) -> &mut Self { |
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331 | 357 | self.is_general_delta = value; |
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332 | 358 | self |
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333 | 359 | } |
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334 | 360 | |
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335 | 361 | pub fn with_version(&mut self, value: u16) -> &mut Self { |
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336 | 362 | self.version = value; |
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337 | 363 | self |
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338 | 364 | } |
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339 | 365 | |
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340 | 366 | pub fn push( |
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341 | 367 | &mut self, |
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342 | 368 | mut index: IndexEntryBuilder, |
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343 | 369 | data: Vec<u8>, |
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344 | 370 | ) -> &mut Self { |
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345 | 371 | if self.index.is_empty() { |
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346 | 372 | index.is_first(true); |
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347 | 373 | index.with_general_delta(self.is_general_delta); |
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348 | 374 | index.with_inline(self.is_inline); |
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349 | 375 | index.with_version(self.version); |
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350 | 376 | } else { |
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351 | 377 | index.with_offset(self.offset); |
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352 | 378 | } |
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353 | 379 | self.index.push(index.build()); |
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354 | 380 | self.offset += data.len(); |
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355 | 381 | self.data.push(data); |
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356 | 382 | self |
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357 | 383 | } |
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358 | 384 | |
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359 | 385 | pub fn build_inline(&self) -> Vec<u8> { |
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360 | 386 | let mut bytes = |
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361 | 387 | Vec::with_capacity(self.index.len() + self.data.len()); |
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362 | 388 | for (index, data) in self.index.iter().zip(self.data.iter()) { |
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363 | 389 | bytes.extend(index); |
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364 | 390 | bytes.extend(data); |
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365 | 391 | } |
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366 | 392 | bytes |
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367 | 393 | } |
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368 | 394 | } |
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369 | 395 | |
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370 | 396 | #[test] |
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371 | 397 | fn is_not_inline_when_no_inline_flag_test() { |
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372 | 398 | let bytes = RevlogBuilder::new() |
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373 | 399 | .with_general_delta(false) |
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374 | 400 | .with_inline(false) |
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375 | 401 | .push(IndexEntryBuilder::new(), vec![]) |
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376 | 402 | .build_inline(); |
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377 | 403 | |
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378 | 404 | assert_eq!(is_inline(&bytes), false) |
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379 | 405 | } |
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380 | 406 | |
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381 | 407 | #[test] |
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382 | 408 | fn is_inline_when_inline_flag_test() { |
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383 | 409 | let bytes = RevlogBuilder::new() |
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384 | 410 | .with_general_delta(false) |
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385 | 411 | .with_inline(true) |
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386 | 412 | .push(IndexEntryBuilder::new(), vec![]) |
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387 | 413 | .build_inline(); |
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388 | 414 | |
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389 | 415 | assert_eq!(is_inline(&bytes), true) |
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390 | 416 | } |
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391 | 417 | |
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392 | 418 | #[test] |
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393 | 419 | fn is_inline_when_inline_and_generaldelta_flags_test() { |
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394 | 420 | let bytes = RevlogBuilder::new() |
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395 | 421 | .with_general_delta(true) |
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396 | 422 | .with_inline(true) |
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397 | 423 | .push(IndexEntryBuilder::new(), vec![]) |
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398 | 424 | .build_inline(); |
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399 | 425 | |
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400 | 426 | assert_eq!(is_inline(&bytes), true) |
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401 | 427 | } |
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402 | 428 | |
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403 | 429 | #[test] |
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404 | 430 | fn version_test() { |
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405 | 431 | let bytes = RevlogBuilder::new() |
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406 | 432 | .with_version(1) |
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407 | 433 | .push(IndexEntryBuilder::new(), vec![]) |
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408 | 434 | .build_inline(); |
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409 | 435 | |
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410 | 436 | assert_eq!(get_version(&bytes), 1) |
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411 | 437 | } |
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412 | 438 | } |
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