about summary refs log tree commit diff
path: root/users/edef/weave/src/main.rs
blob: e8a1990a0df3ebb9445c48ff6fb692d0818880a9 (plain) (blame)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
//! Weave resolves a list of roots from `nixpkgs.roots` against `narinfo.parquet`,
//! and then uses the reference graph from the accompanying `narinfo-references.parquet`
//! produced by `swizzle` to collect the closure of the roots.
//!
//! They are written to `live_idxs.parquet`, which only has one column, representing
//! the row numbers in `narinfo.parquet` corresponding to live paths.

use anyhow::Result;
use hashbrown::{hash_table, HashTable};
use nix_compat::nixbase32;
use rayon::prelude::*;
use std::{
    collections::{BTreeMap, HashSet},
    fs::{self, File},
    ops::Index,
    sync::atomic::{AtomicU32, Ordering},
};

use polars::{
    datatypes::StaticArray,
    export::arrow::{array::UInt32Array, offset::OffsetsBuffer},
    prelude::*,
};

use weave::{hash64, DONE, INDEX_NULL};

fn main() -> Result<()> {
    eprint!("… parse roots\r");
    let roots: PathSet32 = {
        let mut roots = Vec::new();
        fs::read("nixpkgs.roots")?
            .par_chunks_exact(32 + 1)
            .map(|e| nixbase32::decode_fixed::<20>(&e[0..32]).unwrap())
            .collect_into_vec(&mut roots);

        roots.iter().collect()
    };
    eprintln!("{DONE}");

    {
        let ph_array = weave::load_ph_array()?;

        eprint!("… resolve roots\r");
        ph_array.par_iter().enumerate().for_each(|(idx, h)| {
            if let Some(idx_slot) = roots.find(h) {
                idx_slot
                    .compare_exchange(INDEX_NULL, idx as u32, Ordering::SeqCst, Ordering::SeqCst)
                    .expect("duplicate entry");
            }
        });
        eprintln!("{DONE}");
    }

    let mut todo = HashSet::with_capacity(roots.len());
    {
        let mut unknown_roots = 0usize;
        for (_, idx) in roots.table {
            let idx = idx.into_inner();
            if idx == INDEX_NULL {
                unknown_roots += 1;
                continue;
            }
            todo.insert(idx);
        }
        println!("skipping {unknown_roots} unknown roots");
    }

    eprint!("… load reference_idxs\r");
    let ri_array = ParquetReader::new(File::open("narinfo-references.parquet")?)
        .finish()?
        .column("reference_idxs")?
        .list()?
        .clone();

    let ri_array = {
        ChunkedList::new(ri_array.downcast_iter().map(|chunk| {
            (
                chunk.offsets(),
                chunk
                    .values()
                    .as_any()
                    .downcast_ref::<UInt32Array>()
                    .unwrap()
                    .as_slice()
                    .unwrap(),
            )
        }))
    };
    eprintln!("{DONE}");

    let mut seen = todo.clone();
    while !todo.is_empty() {
        println!("todo: {} seen: {}", todo.len(), seen.len());

        todo = todo
            .par_iter()
            .flat_map(|&parent| {
                if parent == INDEX_NULL {
                    return vec![];
                }

                ri_array[parent as usize]
                    .iter()
                    .cloned()
                    .filter(|child| !seen.contains(child))
                    .collect::<Vec<u32>>()
            })
            .collect();

        for &index in &todo {
            seen.insert(index);
        }
    }

    println!("done: {} paths", seen.len());

    if seen.remove(&INDEX_NULL) {
        println!("WARNING: missing edges");
    }

    eprint!("… gathering live set\r");
    let mut seen: Vec<u32> = seen.into_iter().collect();
    seen.par_sort();
    eprintln!("{DONE}");

    eprint!("… writing output\r");
    ParquetWriter::new(File::create("live_idxs.parquet")?).finish(&mut df! {
        "live_idx" => seen,
    }?)?;
    eprintln!("{DONE}");

    Ok(())
}

struct PathSet32 {
    table: HashTable<([u8; 20], AtomicU32)>,
}

impl PathSet32 {
    fn with_capacity(capacity: usize) -> Self {
        Self {
            table: HashTable::with_capacity(capacity),
        }
    }

    fn insert(&mut self, value: &[u8; 20]) -> bool {
        let hash = hash64(value);

        match self
            .table
            .entry(hash, |(x, _)| x == value, |(x, _)| hash64(x))
        {
            hash_table::Entry::Occupied(_) => false,
            hash_table::Entry::Vacant(entry) => {
                entry.insert((*value, AtomicU32::new(INDEX_NULL)));
                true
            }
        }
    }

    fn find(&self, value: &[u8; 20]) -> Option<&AtomicU32> {
        let hash = hash64(value);
        self.table
            .find(hash, |(x, _)| x == value)
            .as_ref()
            .map(|(_, x)| x)
    }

    fn len(&self) -> usize {
        self.table.len()
    }
}

impl<'a> FromIterator<&'a [u8; 20]> for PathSet32 {
    fn from_iter<T: IntoIterator<Item = &'a [u8; 20]>>(iter: T) -> Self {
        let iter = iter.into_iter();
        let mut this = Self::with_capacity(iter.size_hint().0);

        for item in iter {
            this.insert(item);
        }

        this
    }
}

struct ChunkedList<'a, T> {
    by_offset: BTreeMap<usize, (&'a OffsetsBuffer<i64>, &'a [T])>,
}

impl<'a, T> ChunkedList<'a, T> {
    fn new(chunks: impl IntoIterator<Item = (&'a OffsetsBuffer<i64>, &'a [T])>) -> Self {
        let mut next_offset = 0usize;
        ChunkedList {
            by_offset: chunks
                .into_iter()
                .map(|(offsets, values)| {
                    let offset = next_offset;
                    next_offset = next_offset.checked_add(offsets.len_proxy()).unwrap();

                    (offset, (offsets, values))
                })
                .collect(),
        }
    }
}

impl<'a, T> Index<usize> for ChunkedList<'a, T> {
    type Output = [T];

    fn index(&self, index: usize) -> &Self::Output {
        let (&base, &(offsets, values)) = self.by_offset.range(..=index).next_back().unwrap();
        let (start, end) = offsets.start_end(index - base);
        &values[start..end]
    }
}