sva_cli/
solve.rs

1// Concern: runs one solve here: its store, a signal stopping it, progress lines, values written back | Non-concern: the search and the cost (sva-core) | IO: (SolveArgs) -> JSON, an exit, stderr, files
2
3use std::io::Write;
4use std::pin::Pin;
5use std::sync::Arc;
6use std::sync::atomic::{AtomicBool, Ordering};
7
8use sva_ast::variable;
9use sva_core::solve::{
10    Point, Problem, Solved, Stopped, Vary, cost_of, findings, point_json, solve as solved,
11    solved_data,
12};
13use sva_core::{CliError, error_envelope_with, success_envelope};
14use sva_engine::Abandon;
15
16use crate::args::SolveArgs;
17use crate::heard::Heard;
18use crate::store::{On, opened, persisted, wait};
19
20/// The exit a solve stopped by a signal answers, as a shell reports one.
21pub const CANCELLED: u8 = 130;
22
23struct Flagged(Arc<AtomicBool>);
24
25impl Abandon for Flagged {
26    fn abandoned(&self) -> Pin<Box<dyn Future<Output = bool> + '_>> {
27        Box::pin(async { self.0.load(Ordering::Relaxed) })
28    }
29}
30
31/// The envelope and the exit it answers with.
32pub fn solve(args: &SolveArgs) -> Result<(String, u8), CliError> {
33    let dir = crate::composition::composition()?;
34    let heard = Heard::at(&dir)?;
35    let stop = Arc::new(AtomicBool::new(false));
36    let mut warnings = Vec::new();
37    let tier = opened(&args.cache, &mut warnings, On::Flag(&stop))?;
38    let problem = Problem {
39        source: &heard,
40        texts: &heard,
41        cost: cost_of(&heard, &args.cost)?,
42        vary: args.vary.clone(),
43        sets: args.sets.clone(),
44        rate: args.rate,
45        threads: args.threads,
46        stops: args.stops,
47    };
48    let mut heard_point = |point: &Point| {
49        // A reader that closed stderr loses the progress, never the answer.
50        let _ = writeln!(std::io::stderr(), "{}", point_json(point));
51    };
52    let outcome = wait(solved(&problem, tier, &mut heard_point, &Flagged(stop)));
53    persisted(tier, &mut warnings);
54    let solved = outcome?;
55    warnings.extend(findings(&solved, &args.vary));
56    let stopped = solved.stopped_by == Stopped::Cancelled;
57    if stopped {
58        let data = solved_data(&solved, &args.vary, "");
59        let message = format!(
60            "the solve was stopped by a signal after {} render(s); `data` holds the best so far, \
61             and no file was written",
62            solved.renders
63        );
64        let json = error_envelope_with("cancelled", &message, &data, &warnings);
65        return Ok((json, CANCELLED));
66    }
67    if !args.write {
68        let data = solved_data(&solved, &args.vary, "");
69        return Ok((success_envelope(&data, &warnings), 0));
70    }
71    let changes = changed(&dir, &solved, &args.vary)?;
72    let listed = sva_core::json::list(&changes, |c| {
73        format!(
74            "{{ \"path\": \"{}\", \"from\": \"{}\", \"to\": \"{}\" }}",
75            sva_core::json::escape(&c.path),
76            sva_core::json::escape(&c.from),
77            sva_core::json::escape(&c.to)
78        )
79    });
80    if !changes.is_empty() && !args.confirm {
81        let data = solved_data(&solved, &args.vary, &format!(", \"would_write\": {listed}"));
82        let message = format!(
83            "`--write` would change {} variable file(s), and replacing a file needs \
84             `--confirm`; nothing was written",
85            changes.len()
86        );
87        let json = error_envelope_with("conflict", &message, &data, &warnings);
88        return Ok((json, 4));
89    }
90    for change in &changes {
91        std::fs::write(dir.join(&change.path), &change.text)
92            .map_err(|e| CliError::Io(format!("could not write `{}`: {e}", change.path)))?;
93    }
94    let data = solved_data(&solved, &args.vary, &format!(", \"written\": {listed}"));
95    Ok((success_envelope(&data, &warnings), 0))
96}
97
98struct Change {
99    path: String,
100    from: String,
101    to: String,
102    text: String,
103}
104
105/// Each variable whose file would hold another value, its comments kept.
106fn changed(dir: &std::path::Path, solved: &Solved, vary: &[Vary]) -> Result<Vec<Change>, CliError> {
107    let mut out = Vec::new();
108    for ((name, _, to), _) in solved.best.values.iter().zip(vary) {
109        let path = variable(name);
110        let text = std::fs::read_to_string(dir.join(&path))
111            .map_err(|e| CliError::Io(format!("could not read `{path}`: {e}")))?;
112        let at = sva_ast::body_at(&text);
113        let body = &text[at..];
114        let from = sva_ast::strip_line_comment(body).trim().to_string();
115        if from == *to {
116            continue;
117        }
118        let comment = body.find(';').map(|c| format!(" {}", body[c..].trim_end()));
119        out.push(Change {
120            text: format!("{}{to}{}\n", &text[..at], comment.unwrap_or_default()),
121            path,
122            from,
123            to: to.clone(),
124        });
125    }
126    Ok(out)
127}
sva_cli/solve.rs

sva_cli/
solve.rs
