fsqlite-ext-fts3

FTS3/FTS4 full-text search extension for FrankenSQLite.

Overview

This crate implements the FTS3 and FTS4 full-text search extensions. It provides query tokenization and validation (with explicit boolean operators AND, OR, NOT, NEAR, and phrase matching), matchinfo format validation and width computation, and offsets parsing/formatting. FTS3 is the legacy full-text search module; FTS4 is its backward-compatible successor with additional features.

This is a leaf crate in the fsqlite workspace dependency graph. It depends on fsqlite-types, fsqlite-error, and fsqlite-func.

Key Types

• FtsDialect - Enum distinguishing Fts3 and Fts4 dialects
• QueryToken - A parsed token from a full-text query, carrying a QueryTokenKind and the original lexeme
• QueryTokenKind - Token classification: Term, Phrase, And, Or, Not, Near, LParen, RParen
• QueryValidationError - Error enum: EmptyQuery, UnclosedPhrase, UnbalancedParentheses, ImplicitAnd
• MatchinfoFormatError - Error enum for matchinfo format strings: EmptyFormat, InvalidChar, ArithmeticOverflow
• OffsetEntry - A single offset record with column, term, byte_offset, and byte_length fields
• OffsetsParseError - Error enum for offsets parsing: InvalidFieldCount, InvalidInteger

Key Functions

• extension_name() - Returns "fts3"
• supports_dialect(dialect) - Returns whether the given FTS dialect is supported
• parse_query(query) - Tokenize and validate an FTS3/4 query string, rejecting implicit AND and unbalanced parentheses
• validate_matchinfo_format(format) - Validate a matchinfo format string against the allowed character set (p, c, n, a, l, s, x)
• matchinfo_u32_width(format, phrase_count, column_count) - Compute the u32 output width for a matchinfo format string
• parse_offsets(payload) / format_offsets(entries) - Parse and format FTS3/4 offsets function output
• is_matchinfo_format_char(ch) - Check whether a character is valid in a matchinfo format string

Dependencies

• fsqlite-types
• fsqlite-error
• fsqlite-func

License

MIT