Reduce string copies cow #2075
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Reduce string copies cow #2075
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Key points for this commit: - The peekable trait isn't sufficient for using string slices, as we need the byte indexes (start/end) to create string slices, so added the current byte position to the State struct (Note: in the long term we could potentially remove peekable and use only the current position as an iterator) - Created internal functions that create slices from the original query instead of allocating strings, then converted these functions to return String to maintain compatibility (the idea is to make a small, reviewable commit without changing the Token struct or the parser)
Add internal _borrowed() functions that return Cow<\'a, str> to prepare for zero-copy tokenization. When the source string needs no transformation (no escaping), return Cow::Borrowed. When transformation is required, return Cow::Owned. The Token enum still uses String, so borrowed values are converted via to_owned() for now. This maintains API compatibility while preparing the codebase for a future refactor where Token can hold borrowed strings. Optimized: comments, quoted strings, dollar-quoted strings, quoted identifiers.
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FYI @iffyio and @yoavcloud |
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This continues the preparation for a borrowed Tokenizer (#2036) and adds more internal functions that borrow strings during tokenization.
This commit also handles places where the Tokenizer could modify the original strings. In such cases, the strategy is to create functions that return
Cow<'a, str>and create an owned version of the string when modification is needed.This commit is rebased on PR #2073 and will remain in draft until #2073 is reviewed.