Claude
41e28a8ab7
- PCRE2: compile with the ANYCRLF newline convention and DOLLAR_ENDONLY,
as ECMAScript reads '.' and '$'. With PCRE2's default (LF only) '.'
matched the CR of a CRLF line, so regex replace-all deleted CRs.
- Replacement $0 is the whole match, two digits are read greedily and a
group the pattern lacks expands to nothing, as std::regex_replace
(libstdc++) does; these cases are now compared in the tests.
- Plain search visits overlapping matches going forward too, and counts
them, as the backward search found them ('aa' in 'aaa' read 2/1).
- The recovery prompt's replayed content is used on 'y' only if the
journal is unchanged since; otherwise it is replayed again.
- A version 1 journal continued after recovery is rewritten as a
compacted version 2 journal when it needs a chunked checkpoint,
instead of receiving records an older kte would skip. (The version is
read through a separate descriptor: the journal fd is write-only.)
Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_015rcVQiiWyTzoNrsvLSaAfB
72 lines
2.5 KiB
C++
72 lines
2.5 KiB
C++
/*
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* RegexEngine.h - the regex engine behind search, replace and match
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* highlighting.
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*
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* With KTE_USE_PCRE2 (the default when libpcre2-8 is found) patterns are
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* compiled by PCRE2 with its JIT: typically one to two orders of magnitude
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* faster than std::regex, no recursion on the C stack, and a match limit
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* that stops catastrophic backtracking (e.g. "^(a+)+$") instead of hanging
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* the editor. Otherwise std::regex (ECMAScript) is used, run on a large
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* stack (see RegexGuard.h). The syntax both accept covers ordinary use;
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* PCRE2 additionally has lookbehind, possessive quantifiers and the like.
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*
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* Replacement strings use ECMAScript syntax with either engine, as
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* std::regex_replace (libstdc++) reads it: $& or $0 (the match), $1..$99
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* (groups, two digits read greedily; a group the pattern lacks expands to
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* nothing), $` (the text since the previous match), $' (the rest of the
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* line), $$ (a dollar sign). As in ECMAScript, '.' matches neither CR nor
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* LF and '$' matches only at the end of the line's text.
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*/
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#pragma once
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#include <cstddef>
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#include <memory>
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#include <string>
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#include <string_view>
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namespace kte {
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class Regex {
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public:
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Regex();
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~Regex();
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Regex(Regex &&other) noexcept;
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Regex &operator=(Regex &&other) noexcept;
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Regex(const Regex &) = delete;
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Regex &operator=(const Regex &) = delete;
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// Compile; on failure err describes the problem and Valid() is false.
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bool Compile(std::string_view pattern, std::string &err);
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[[nodiscard]] bool Valid() const;
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// The first match in `subject` starting at byte `from` or later; `from`
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// may be inside the subject (anchors and lookbehind see what precedes
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// it). False if there is none, or if the engine gave up (LimitHit()).
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bool Search(std::string_view subject, std::size_t from, std::size_t &pos, std::size_t &len) const;
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// Every non-overlapping match replaced by `fmt` (ECMAScript syntax, see
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// above); an empty match is not repeated at the same position.
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[[nodiscard]] std::string ReplaceAll(std::string_view subject, std::string_view fmt) const;
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// Whether the last Search/ReplaceAll stopped at the engine's match limit.
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[[nodiscard]] bool LimitHit() const;
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// "PCRE2" or "std::regex".
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static const char *EngineName();
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// The longest line search-as-you-type and match highlighting run the
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// regex over (per keystroke/frame); std::regex can be quadratic in line
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// length with no way to interrupt it, PCRE2 is bounded by its limit.
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static std::size_t IncrementalLineLimit();
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private:
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struct Impl;
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std::unique_ptr<Impl> impl_;
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};
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} // namespace kte
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