| 1 | //! `alt` module contains a set of auxiliary functions that can be used for common operations |
| 2 | //! over document [Update]s directly on their binary representation. |
| 3 | |
| 4 | use crate::encoding::read::{Cursor, Error}; |
| 5 | use crate::update::Update; |
| 6 | use crate::updates::decoder::{Decode, DecoderV2}; |
| 7 | use crate::updates::encoder::{Encode, Encoder, EncoderV1, EncoderV2}; |
| 8 | use crate::StateVector; |
| 9 | |
| 10 | /// Merges a sequence of updates (encoded using lib0 v1 encoding) together, producing another |
| 11 | /// update (also lib0 v1 encoded) in the result. Returned binary is a combination of all input |
| 12 | /// `updates`, compressed. |
| 13 | /// |
| 14 | /// Returns an error whenever any of the input updates couldn't be decoded. |
| 15 | pub fn merge_updates_v1<I, B>(updates: I) -> Result<Vec<u8>, Error> |
| 16 | where |
| 17 | I: IntoIterator<Item = B>, |
| 18 | B: AsRef<[u8]>, |
| 19 | { |
| 20 | let mut i = updates.into_iter(); |
| 21 | let (lo, hi) = i.size_hint(); |
| 22 | let mut merge = Vec::with_capacity(hi.unwrap_or(lo)); |
| 23 | while let Some(buf) = i.next() { |
| 24 | let parsed = Update::decode_v1(buf.as_ref())?; |
| 25 | merge.push(parsed); |
| 26 | } |
| 27 | Ok(Update::merge_updates(merge).encode_v1()) |
| 28 | } |
| 29 | |
| 30 | /// Merges a sequence of updates (encoded using lib0 v2 encoding) together, producing another |
| 31 | /// update (also lib0 v2 encoded) in the result. Returned binary is a combination of all input |
| 32 | /// `updates`, compressed. |
| 33 | /// |
| 34 | /// Returns an error whenever any of the input updates couldn't be decoded. |
| 35 | pub fn merge_updates_v2<I, B>(updates: I) -> Result<Vec<u8>, Error> |
| 36 | where |
| 37 | I: IntoIterator<Item = B>, |
| 38 | B: AsRef<[u8]>, |
| 39 | { |
| 40 | let mut i = updates.into_iter(); |
| 41 | let (lo, hi) = i.size_hint(); |
| 42 | let mut merge = Vec::with_capacity(hi.unwrap_or(lo)); |
| 43 | while let Some(buf) = i.next() { |
| 44 | let update = Update::decode_v2(buf.as_ref())?; |
| 45 | merge.push(update); |
| 46 | } |
| 47 | Ok(Update::merge_updates(merge).encode_v2()) |
| 48 | } |
| 49 | |
| 50 | /// Decodes a input `update` (encoded using lib0 v1 encoding) and returns an encoded [StateVector] |
| 51 | /// of that update. |
| 52 | /// |
| 53 | /// Returns an error whenever any of the input update couldn't be decoded. |
| 54 | pub fn encode_state_vector_from_update_v1(update: &[u8]) -> Result<Vec<u8>, Error> { |
| 55 | let update = Update::decode_v1(update)?; |
| 56 | Ok(update.state_vector().encode_v1()) |
| 57 | } |
| 58 | |
| 59 | /// Decodes a input `update` (encoded using lib0 v2 encoding) and returns an encoded [StateVector] |
| 60 | /// of that update. |
| 61 | /// |
| 62 | /// Returns an error whenever any of the input update couldn't be decoded. |
| 63 | pub fn encode_state_vector_from_update_v2(update: &[u8]) -> Result<Vec<u8>, Error> { |
| 64 | let update = Update::decode_v2(update)?; |
| 65 | Ok(update.state_vector().encode_v2()) |
| 66 | } |
| 67 | |
| 68 | /// Givens an input `update` (encoded using lib0 v1 encoding) of document **A** and an encoded |
| 69 | /// `state_vector` of document **B**, returns a lib0 v1 encoded update, that contains all changes |
| 70 | /// from **A** which have not been observed by **B** (based on its state vector). |
| 71 | /// |
| 72 | /// Returns an error whenever any of the input arguments couldn't be decoded. |
| 73 | pub fn diff_updates_v1(update: &[u8], state_vector: &[u8]) -> Result<Vec<u8>, Error> { |
| 74 | let sv = StateVector::decode_v1(state_vector)?; |
| 75 | let update = Update::decode_v1(update)?; |
| 76 | let mut encoder = EncoderV1::new(); |
| 77 | update.encode_diff(&sv, &mut encoder); |
| 78 | // for delete set, don't decode/encode it - just copy the remaining part from the decoder |
| 79 | let result = encoder.to_vec(); |
| 80 | Ok(result) |
| 81 | } |
| 82 | |
| 83 | /// Givens an input `update` (encoded using lib0 v2 encoding) of document **A** and an encoded |
| 84 | /// `state_vector` of document **B**, returns a lib0 v2 encoded update, that contains all changes |
| 85 | /// from **A** which have not been observed by **B** (based on its state vector). |
| 86 | /// |
| 87 | /// Returns an error whenever any of the input arguments couldn't be decoded. |
| 88 | pub fn diff_updates_v2(update: &[u8], state_vector: &[u8]) -> Result<Vec<u8>, Error> { |
| 89 | let sv = StateVector::decode_v2(state_vector)?; |
| 90 | let cursor = Cursor::new(update); |
| 91 | let mut decoder = DecoderV2::new(cursor)?; |
| 92 | let update = Update::decode(&mut decoder)?; |
| 93 | let mut encoder = EncoderV2::new(); |
| 94 | update.encode_diff(&sv, &mut encoder); |
| 95 | // for delete set, don't decode/encode it - just copy the remaining part from the decoder |
| 96 | Ok(encoder.to_vec()) |
| 97 | } |
| 98 | |
| 99 | #[cfg(test)] |
| 100 | mod test { |
| 101 | use crate::{diff_updates_v1, encode_state_vector_from_update_v1, merge_updates_v1}; |
| 102 | |
| 103 | #[test] |
| 104 | fn merge_updates_compatibility_v1() { |
| 105 | let a = vec![ |
| 106 | 1, 1, 220, 240, 237, 172, 15, 0, 4, 1, 4, 116, 101, 115, 116, 3, 97, 98, 99, 0, |
| 107 | ]; |
| 108 | let b = vec![ |
| 109 | 1, 1, 201, 139, 250, 201, 1, 0, 4, 1, 4, 116, 101, 115, 116, 2, 100, 101, 0, |
| 110 | ]; |
| 111 | let expected = vec![ |
| 112 | 2, 1, 220, 240, 237, 172, 15, 0, 4, 1, 4, 116, 101, 115, 116, 3, 97, 98, 99, 1, 201, |
| 113 | 139, 250, 201, 1, 0, 4, 1, 4, 116, 101, 115, 116, 2, 100, 101, 0, |
| 114 | ]; |
| 115 | |
| 116 | let actual = merge_updates_v1(&[a, b]).unwrap(); |
| 117 | assert_eq!(actual, expected); |
| 118 | } |
| 119 | |
| 120 | #[test] |
| 121 | fn merge_updates_compatibility_v1_2() { |
| 122 | let a = &[ |
| 123 | 1, 1, 129, 231, 135, 164, 7, 0, 4, 1, 4, 49, 50, 51, 52, 1, 97, 0, |
| 124 | ]; |
| 125 | let b = &[ |
| 126 | 1, 1, 129, 231, 135, 164, 7, 1, 68, 129, 231, 135, 164, 7, 0, 1, 98, 0, |
| 127 | ]; |
| 128 | let expected = &[ |
| 129 | 1, 2, 129, 231, 135, 164, 7, 0, 4, 1, 4, 49, 50, 51, 52, 1, 97, 68, 129, 231, 135, 164, |
| 130 | 7, 0, 1, 98, 0, |
| 131 | ]; |
| 132 | |
| 133 | let actual = merge_updates_v1(&[a, b]).unwrap(); |
| 134 | assert_eq!(actual, expected); |
| 135 | } |
| 136 | |
| 137 | #[test] |
| 138 | fn encode_state_vector_compatibility_v1() { |
| 139 | let update = &[ |
| 140 | 2, 1, 220, 240, 237, 172, 15, 0, 4, 1, 4, 116, 101, 115, 116, 3, 97, 98, 99, 1, 201, |
| 141 | 139, 250, 201, 1, 0, 4, 1, 4, 116, 101, 115, 116, 2, 100, 101, 0, |
| 142 | ]; |
| 143 | let expected = &[2, 220, 240, 237, 172, 15, 3, 201, 139, 250, 201, 1, 2]; |
| 144 | let actual = encode_state_vector_from_update_v1(update).unwrap(); |
| 145 | assert_eq!(actual, expected); |
| 146 | } |
| 147 | |
| 148 | #[test] |
| 149 | fn diff_updates_compatibility_v1() { |
| 150 | let state_vector = &[1, 148, 189, 145, 162, 9, 3]; |
| 151 | let update = &[ |
| 152 | 1, 2, 148, 189, 145, 162, 9, 0, 4, 1, 4, 116, 101, 115, 116, 3, 97, 98, 99, 68, 148, |
| 153 | 189, 145, 162, 9, 0, 2, 100, 101, 0, |
| 154 | ]; |
| 155 | let expected = &[ |
| 156 | 1, 1, 148, 189, 145, 162, 9, 3, 68, 148, 189, 145, 162, 9, 0, 2, 100, 101, 0, |
| 157 | ]; |
| 158 | let actual = diff_updates_v1(update, state_vector).unwrap(); |
| 159 | assert_eq!(actual, expected); |
| 160 | } |
| 161 | } |
| 162 | |
amadan