trg/

search.rs

//! Search configuration and the `-m` sink. Deliberately thin: the matching
//! engine is ripgrep's, unmodified.

use std::io;
use std::path::Path;

use grep_searcher::{
    BinaryDetection, Searcher, SearcherBuilder, Sink, SinkContext, SinkFinish, SinkMatch,
};

pub struct SearchOpts {
    pub case_insensitive: bool,
    pub smart_case: bool,
    pub word: bool,
    pub fixed: bool,
    pub invert: bool,
    pub before: usize,
    pub after: usize,
    pub line_numbers: bool,
    /// `-a`: search members that look binary.
    pub text: bool,
    pub max_count: Option<u64>,
    pub heap_limit: usize,
    /// `--crlf`: treat CRLF as the line terminator. Off by default — see
    /// `agrees_with_rg_on_anchored_patterns` in `tests/differential.rs` for
    /// why this must never be hard-coded on.
    pub crlf: bool,
}

impl Default for SearchOpts {
    fn default() -> Self {
        Self {
            case_insensitive: false,
            smart_case: false,
            word: false,
            fixed: false,
            invert: false,
            before: 0,
            after: 0,
            line_numbers: true,
            text: false,
            max_count: None,
            heap_limit: 16 * 1024 * 1024,
            crlf: false,
        }
    }
}

pub fn build_matcher(
    pats: &[String],
    o: &SearchOpts,
) -> anyhow::Result<grep_regex::RegexMatcher> {
    // Built as ripgrep builds it: multi-line, so `^` and `$` hold at every line
    // and not only at the edges of whatever buffer the searcher hands over,
    // with `\n` as the line terminator so no match can span two lines. Built
    // single-line, `-o '^[0-9.]+'` matched the first line and printed every
    // later hit whole.
    let mut b = grep_regex::RegexMatcherBuilder::new();
    b.case_insensitive(o.case_insensitive)
        .case_smart(o.smart_case)
        .word(o.word)
        .fixed_strings(o.fixed)
        .multi_line(true)
        .line_terminator(Some(b'\n'))
        .crlf(o.crlf);
    Ok(b.build_many(pats)?)
}

pub fn build_searcher(o: &SearchOpts) -> Searcher {
    let mut b = SearcherBuilder::new();
    b.line_number(o.line_numbers)
        .before_context(o.before)
        .after_context(o.after)
        .invert_match(o.invert)
        .heap_limit(Some(o.heap_limit))
        .binary_detection(if o.text {
            BinaryDetection::none()
        } else {
            BinaryDetection::quit(b'\x00')
        });
    if o.crlf {
        b.line_terminator(grep_matcher::LineTerminator::crlf());
    }
    b.build()
}

/// `-m/--max-count`. `StandardBuilder` has no `max_matches`, so the limit is
/// enforced by wrapping the printer's sink and returning `Ok(false)` from
/// `matched`, which stops the search.
pub struct MaxCount<S> {
    inner: S,
    limit: Option<u64>,
    seen: u64,
    binary_at: Option<u64>,
}

impl<S: Sink> MaxCount<S> {
    pub fn new(inner: S, limit: Option<u64>) -> Self {
        Self { inner, limit, seen: 0, binary_at: None }
    }

    /// Whether the searcher reported any match at all for this member.
    ///
    /// This, and not the printer's own summary, is the exit code's source of
    /// truth. See the note on `matched` below for why the difference matters.
    pub fn saw_match(&self) -> bool {
        self.seen > 0
    }

    /// Matched, then ran into binary data — the one combination that makes
    /// `SummarySink` retract its count and print nothing.
    ///
    /// Read from the searcher's own `SinkFinish`, which is the same value
    /// `SummarySink::finish` consults before squashing `match_count` to zero,
    /// so the two can never disagree about whether a count was suppressed.
    /// Only `-c` cares: `-l` prints the path, `--json` emits its records and
    /// the default printer emits a binary warning of its own.
    pub fn count_suppressed_by_binary(&self) -> bool {
        self.seen > 0 && self.binary_at.is_some()
    }
}

impl<S: Sink> Sink for MaxCount<S> {
    type Error = S::Error;

    fn matched(&mut self, s: &Searcher, m: &SinkMatch<'_>) -> Result<bool, S::Error> {
        // Counted *before* the inner sink is consulted, and this ordering is
        // load-bearing twice over.
        //
        // A printer is allowed to say "stop, I have seen enough" — `-l` and
        // `-q` both quit on their first match — and a printer is allowed to
        // revise what it reports afterwards: `SummarySink::finish` zeroes its
        // own `match_count` whenever binary data was seen under
        // `BinaryDetection::quit`, which grep-printer's source calls "an
        // unfortunate inconsistency ... we accept the bug". That is a
        // reasonable answer to rg's question ("is this file worth showing
        // you?") and the wrong answer to ours, because exit 1 here is a
        // positive claim that the logs are clean.
        //
        // Counting first makes `seen` the record of what the *searcher*
        // reported, which no printer can overrule and no early stop can
        // truncate. The `-m` limit is unaffected: when the inner sink stops the
        // search, its own count no longer decides anything.
        self.seen += 1;
        if !self.inner.matched(s, m)? {
            return Ok(false);
        }
        Ok(match self.limit {
            Some(n) => self.seen < n,
            None => true,
        })
    }

    fn context(&mut self, s: &Searcher, c: &SinkContext<'_>) -> Result<bool, S::Error> {
        self.inner.context(s, c)
    }

    fn context_break(&mut self, s: &Searcher) -> Result<bool, S::Error> {
        self.inner.context_break(s)
    }

    fn binary_data(&mut self, s: &Searcher, off: u64) -> Result<bool, S::Error> {
        self.inner.binary_data(s, off)
    }

    // `Sink` gives `begin` and `finish` default no-op implementations, so a
    // wrapper that forgets to forward them silently swallows them. That is not
    // cosmetic: `SummarySink` writes its whole result — the `-c` count line,
    // the `-l` path — from `finish`, and resets its per-search match count in
    // `begin`. Without these two, `-c` and `-l` print nothing at all.
    fn begin(&mut self, s: &Searcher) -> Result<bool, S::Error> {
        self.seen = 0;
        self.binary_at = None;
        self.inner.begin(s)
    }

    fn finish(&mut self, s: &Searcher, f: &SinkFinish) -> Result<(), S::Error> {
        self.binary_at = f.binary_byte_offset();
        self.inner.finish(s, f)
    }
}

/// `archive.tgz:logs/vhost03.access.log`, or just the path for a plain file.
pub fn display_path(archive: &Path, member: &str, sep: char) -> String {
    if member.is_empty() {
        archive.display().to_string()
    } else {
        format!("{}{}{}", archive.display(), sep, member)
    }
}

/// Everything a search needs that is the same for every archive in a run.
///
/// Borrowed and shared across the whole scheduler: it is `Sync`, so one
/// instance is read by every worker. The per-job values — the path, the
/// `Searcher`, the printer, and the inflate strategy — stay as arguments,
/// because each worker must own its own (`Searcher` is not `Sync`) and the
/// strategy is chosen per file from its size.
pub struct SearchCtx<'a> {
    pub matcher: &'a grep_regex::RegexMatcher,
    pub sep: char,
    pub globs: Option<&'a crate::source::Globs>,
    pub max_count: Option<u64>,
    /// A request, not a decision: `walk_archive` narrows it to
    /// archives, so a plain live logfile is never evicted.
    pub drop_cache: bool,
    /// Whether the run is in `-c` mode. Not used to choose a printer — `cli`
    /// already did that — only to decide whether a suppressed count is worth a
    /// note on stderr.
    pub count_mode: bool,
}

/// Whether `-g` excludes this input, for the one case `for_each_member` cannot
/// decide on its own.
///
/// `-g` filters at the finest available granularity: tar member names for
/// archives, which `for_each_member` applies itself, and the file's own path
/// for plain (non-tar) files, which arrive here as a single member named `""`.
/// Without this second half, a mixed sweep of live logs plus archives would
/// ignore `-g` for every live log.
fn excluded_plain_file(member: &str, path: &Path, globs: Option<&crate::source::Globs>) -> bool {
    member.is_empty() && globs.is_some_and(|set| !set.is_match(path))
}

/// What one member's search concluded, beyond the bytes it printed.
pub struct MemberVerdict {
    pub matched: bool,
    /// The member matched but `-c` printed no count line for it.
    pub count_suppressed: bool,
}

/// Search one member, returning whether it matched.
///
/// "Did this member match" comes from [`MaxCount::saw_match`] — the searcher's
/// own tally — and from neither of the two tempting alternatives. Not from
/// whether bytes reached the buffer: `-q` matches and writes nothing, and `-c`
/// writes a line whose content is a count. And not from the sink's
/// `has_match()` either, because `SummarySink` retracts that after seeing
/// binary data, which would make `-c` exit 1 on an archive `-l`, `-q`,
/// `--json` and the default mode all agree matched.
fn search_member(
    printer: &mut crate::print::Printer<'_>,
    m: &grep_regex::RegexMatcher,
    s: &mut Searcher,
    r: &mut dyn io::Read,
    display: &str,
    max_count: Option<u64>,
) -> io::Result<MemberVerdict> {
    // The three printers have unrelated sink types, so the body is monomorphic
    // per arm; a macro keeps the one real sequence — build sink, cap it,
    // search, ask it what it saw — written once.
    macro_rules! run {
        ($p:expr) => {{
            let sink = $p.sink_with_path(m, display);
            let mut capped = MaxCount::new(sink, max_count);
            let res = s.search_reader(m, r, &mut capped);
            // Read the verdict before propagating: a member that matched and
            // *then* hit a read error still matched, and the error is recorded
            // separately by the caller.
            let hit = capped.saw_match();
            let suppressed = capped.count_suppressed_by_binary();
            res.map_err(io::Error::other)?;
            MemberVerdict { matched: hit, count_suppressed: suppressed }
        }};
    }

    Ok(match printer {
        crate::print::Printer::Standard(p) => run!(p),
        crate::print::Printer::Summary(p) => run!(p),
        crate::print::Printer::Json(p) => run!(p),
    })
}

/// Search one archive into `printer`'s buffer.
pub fn search_archive(
    ctx: &SearchCtx<'_>,
    path: &Path,
    s: &mut Searcher,
    printer: &mut crate::print::Printer<'_>,
) -> crate::archive::Outcome {
    let (m, sep, globs, max_count) = (ctx.matcher, ctx.sep, ctx.globs, ctx.max_count);

    let mut matched = false;
    let mut notes: Vec<String> = Vec::new();
    let mut out = crate::archive::walk_archive(path, ctx.drop_cache, globs, |member, r| {
        if excluded_plain_file(member, path, globs) {
            return Ok(());
        }
        let display = display_path(path, member, sep);
        let v = search_member(printer, m, s, r, &display, max_count)?;
        matched |= v.matched;
        // `-c` is otherwise the only mode that goes completely silent on a
        // member that matched and then hit binary data: stdout stays empty and
        // the exit code stays 0, so `n=$(trg -c PAT a.tgz)` yields '' and a
        // script testing `((n>0))` concludes the logs are clean. stdout must
        // not change — it is rg-compatible, and the count really is unknown —
        // so the correction goes to stderr, where it costs a pipeline nothing
        // and an operator everything.
        if ctx.count_mode && v.count_suppressed {
            notes.push(format!("{display}: binary data; count suppressed"));
        }
        Ok(())
    });
    // A note, not an error: nothing is known to be missing, and the format
    // offers no way to find out. But a 1 is someone's "the logs are clean",
    // and this file cannot back it up.
    if out.unverified_end && !matched && out.errors.is_empty() {
        notes.push(format!(
            "{}: no match, but .Z cannot detect truncation: a cut-off file reads as a shorter one",
            path.display()
        ));
    }
    out.matched = matched;
    out.notes = notes;
    out
}

/// `-T/--list-members`: print member paths without searching.
///
/// Deliberately does **not** short-circuit on the first member: the exit-code
/// contract applies here too, so the whole archive is walked and any failure
/// on the way lands in `Outcome.errors`.
///
/// Lists every regular member, including ones a *search* would skip as binary.
/// Listing is a question about the tar header; skipping a binary member is a
/// question about its content, which `-T` never reads.
///
/// Takes the same `ctx` as [`search_archive`], and opens through the same
/// [`crate::archive::walk_archive`], because `-T` walks exactly as
/// many bytes of exactly the same archives. Opening through the plain
/// `open_decoded` instead would make `-T` the one mode that leaves a sweep's
/// worth of archive pages in the cache —
/// precisely the pollution the cache-dropping work exists to prevent.
pub fn list_members(
    ctx: &SearchCtx<'_>,
    path: &Path,
    out: &mut dyn io::Write,
) -> crate::archive::Outcome {
    let (sep, globs) = (ctx.sep, ctx.globs);

    let mut listed = false;
    let mut outcome = crate::archive::walk_archive(path, ctx.drop_cache, globs, |member, _| {
        if excluded_plain_file(member, path, globs) {
            return Ok(());
        }
        listed = true;
        writeln!(out, "{}", display_path(path, member, sep))
    });
    // `-T` has no notion of a match, so "listed something" is what stands in
    // for it: `trg -T ... ; echo $?` should say 1 when an archive held nothing
    // the globs would accept, the same shape of answer as a search.
    outcome.matched = listed;
    outcome
}