a6e69d9518
Avoid repeatedly decoding an entire byte-backed UTF-8 source when a cached function asks for its source text and the script contains a non-ASCII code point before the requested range. Build a small map from UTF-16 code unit offsets to byte offsets on demand for valid UTF-8 sources, then slice the source bytes directly for subsequent extractions. Invalid or non-UTF-8 sources keep using the existing decoder fallback. Add coverage for lazy range extraction after non-ASCII UTF-8 and for bytecode-cache materialization of function source text from such a script.
79 lines
2.9 KiB
C++
79 lines
2.9 KiB
C++
/*
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* Copyright (c) 2022-2023, Andreas Kling <andreas@ladybird.org>
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*
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* SPDX-License-Identifier: BSD-2-Clause
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*/
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#pragma once
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#include <AK/Optional.h>
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#include <AK/String.h>
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#include <AK/Utf16String.h>
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#include <AK/Vector.h>
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#include <LibCore/ImmutableBytes.h>
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#include <LibJS/Export.h>
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#include <LibJS/Forward.h>
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#include <LibJS/Position.h>
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namespace JS {
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class JS_API SourceCode : public RefCounted<SourceCode> {
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public:
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static NonnullRefPtr<SourceCode const> create(String filename, Utf16String code);
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static NonnullRefPtr<SourceCode const> create(String filename, size_t length_in_code_units, String source_encoding, Core::ImmutableBytes source_bytes);
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String const& filename() const { return m_filename; }
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Utf16String const& code() const;
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Utf16View const& code_view() const;
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size_t length_in_code_units() const { return m_length_in_code_units; }
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u16 const* utf16_data() const;
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Utf16String source_text_from_offsets(size_t start_offset, size_t length) const;
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SourceRange range_from_offsets(u32 start_offset, u32 end_offset) const;
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private:
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SourceCode(String filename, Utf16String code);
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SourceCode(String filename, size_t length_in_code_units, String source_encoding, Core::ImmutableBytes source_bytes);
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void ensure_code() const;
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Utf16String decode_source_range(size_t start_offset, size_t length) const;
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bool source_bytes_can_be_sliced_by_code_unit_offsets() const;
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Optional<Utf16String> source_text_from_utf8_source_bytes(size_t start_offset, size_t length) const;
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bool ensure_utf8_source_byte_spans() const;
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Optional<size_t> byte_offset_for_utf8_code_unit_offset(size_t code_unit_offset) const;
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struct Utf8SourceByteSpan {
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size_t code_unit_offset { 0 };
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size_t code_unit_length { 0 };
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size_t byte_offset { 0 };
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size_t byte_length { 0 };
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};
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String m_filename;
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Optional<Utf16String> mutable m_code;
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String m_source_encoding;
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Core::ImmutableBytes mutable m_source_bytes;
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Utf16View mutable m_code_view;
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size_t m_length_in_code_units { 0 };
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// For fast mapping of offsets to line/column numbers, we build a list of
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// starting points (with byte offsets into the source string) and which
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// line:column they map to. This can then be binary-searched.
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void fill_position_cache() const;
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struct CachedPosition {
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Position position;
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u32 offset { 0 };
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};
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Vector<CachedPosition> mutable m_cached_positions;
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// Cached UTF-16 widening of ASCII source data, lazily populated by
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// utf16_data() for use by the Rust compilation pipeline.
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Vector<u16> mutable m_utf16_data_cache;
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Optional<bool> mutable m_source_bytes_can_be_sliced_by_code_unit_offsets;
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Vector<Utf8SourceByteSpan> mutable m_utf8_source_byte_spans;
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size_t mutable m_utf8_source_byte_span_initial_byte_offset { 0 };
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bool mutable m_tried_to_build_utf8_source_byte_spans { false };
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bool mutable m_can_use_utf8_source_byte_spans { false };
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};
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}
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