Everywhere: Hoist the Libraries folder to the top-level

Author: https://github.com/trflynn89
Commit: 93712b24bf
Pull-request: https://github.com/LadybirdBrowser/ladybird/pull/2256
Reviewed-by: https://github.com/sideshowbarker

Libraries/LibRegex/RegexMatcher.cpp

@@ -0,0 +1,588 @@
+/*
+ * Copyright (c) 2020, Emanuel Sprung <emanuel.sprung@gmail.com>
+ *
+ * SPDX-License-Identifier: BSD-2-Clause
+ */
+
+#include <AK/BumpAllocator.h>
+#include <AK/ByteString.h>
+#include <AK/Debug.h>
+#include <AK/StringBuilder.h>
+#include <LibRegex/RegexMatcher.h>
+#include <LibRegex/RegexParser.h>
+
+#if REGEX_DEBUG
+#    include <LibRegex/RegexDebug.h>
+#endif
+
+namespace regex {
+
+#if REGEX_DEBUG
+static RegexDebug s_regex_dbg(stderr);
+#endif
+
+template<class Parser>
+regex::Parser::Result Regex<Parser>::parse_pattern(StringView pattern, typename ParserTraits<Parser>::OptionsType regex_options)
+{
+    regex::Lexer lexer(pattern);
+
+    Parser parser(lexer, regex_options);
+    return parser.parse();
+}
+
+template<typename Parser>
+struct CacheKey {
+    ByteString pattern;
+    typename ParserTraits<Parser>::OptionsType options;
+
+    bool operator==(CacheKey const& other) const
+    {
+        return pattern == other.pattern && options.value() == other.options.value();
+    }
+};
+template<class Parser>
+static OrderedHashMap<CacheKey<Parser>, regex::Parser::Result> s_parser_cache;
+
+template<class Parser>
+static size_t s_cached_bytecode_size = 0;
+
+static constexpr auto MaxRegexCachedBytecodeSize = 1 * MiB;
+
+template<class Parser>
+Regex<Parser>::Regex(ByteString pattern, typename ParserTraits<Parser>::OptionsType regex_options)
+    : pattern_value(move(pattern))
+{
+    if (auto cache_entry = s_parser_cache<Parser>.get({ pattern_value, regex_options }); cache_entry.has_value()) {
+        parser_result = cache_entry.value();
+    } else {
+        regex::Lexer lexer(pattern_value);
+
+        Parser parser(lexer, regex_options);
+        parser_result = parser.parse();
+
+        run_optimization_passes();
+        if (parser_result.error == regex::Error::NoError) {
+            while (parser_result.bytecode.size() * sizeof(ByteCodeValueType) + s_cached_bytecode_size<Parser> > MaxRegexCachedBytecodeSize)
+                s_cached_bytecode_size<Parser> -= s_parser_cache<Parser>.take_first().bytecode.size() * sizeof(ByteCodeValueType);
+            s_parser_cache<Parser>.set({ pattern_value, regex_options }, parser_result);
+            s_cached_bytecode_size<Parser> += parser_result.bytecode.size() * sizeof(ByteCodeValueType);
+        }
+    }
+
+    if (parser_result.error == regex::Error::NoError)
+        matcher = make<Matcher<Parser>>(this, static_cast<decltype(regex_options.value())>(parser_result.options.value()));
+}
+
+template<class Parser>
+Regex<Parser>::Regex(regex::Parser::Result parse_result, ByteString pattern, typename ParserTraits<Parser>::OptionsType regex_options)
+    : pattern_value(move(pattern))
+    , parser_result(move(parse_result))
+{
+    run_optimization_passes();
+    if (parser_result.error == regex::Error::NoError)
+        matcher = make<Matcher<Parser>>(this, regex_options | static_cast<decltype(regex_options.value())>(parse_result.options.value()));
+}
+
+template<class Parser>
+Regex<Parser>::Regex(Regex&& regex)
+    : pattern_value(move(regex.pattern_value))
+    , parser_result(move(regex.parser_result))
+    , matcher(move(regex.matcher))
+    , start_offset(regex.start_offset)
+{
+    if (matcher)
+        matcher->reset_pattern({}, this);
+}
+
+template<class Parser>
+Regex<Parser>& Regex<Parser>::operator=(Regex&& regex)
+{
+    pattern_value = move(regex.pattern_value);
+    parser_result = move(regex.parser_result);
+    matcher = move(regex.matcher);
+    if (matcher)
+        matcher->reset_pattern({}, this);
+    start_offset = regex.start_offset;
+    return *this;
+}
+
+template<class Parser>
+typename ParserTraits<Parser>::OptionsType Regex<Parser>::options() const
+{
+    if (!matcher || parser_result.error != Error::NoError)
+        return {};
+
+    return matcher->options();
+}
+
+template<class Parser>
+ByteString Regex<Parser>::error_string(Optional<ByteString> message) const
+{
+    StringBuilder eb;
+    eb.append("Error during parsing of regular expression:\n"sv);
+    eb.appendff("    {}\n    ", pattern_value);
+    for (size_t i = 0; i < parser_result.error_token.position(); ++i)
+        eb.append(' ');
+
+    eb.appendff("^---- {}", message.value_or(get_error_string(parser_result.error)));
+    return eb.to_byte_string();
+}
+
+template<typename Parser>
+RegexResult Matcher<Parser>::match(RegexStringView view, Optional<typename ParserTraits<Parser>::OptionsType> regex_options) const
+{
+    AllOptions options = m_regex_options | regex_options.value_or({}).value();
+
+    if constexpr (!IsSame<Parser, ECMA262>) {
+        if (options.has_flag_set(AllFlags::Multiline))
+            return match(view.lines(), regex_options); // FIXME: how do we know, which line ending a line has (1char or 2char)? This is needed to get the correct match offsets from start of string...
+    }
+
+    Vector<RegexStringView> views;
+    views.append(view);
+    return match(views, regex_options);
+}
+
+template<typename Parser>
+RegexResult Matcher<Parser>::match(Vector<RegexStringView> const& views, Optional<typename ParserTraits<Parser>::OptionsType> regex_options) const
+{
+    // If the pattern *itself* isn't stateful, reset any changes to start_offset.
+    if (!((AllFlags)m_regex_options.value() & AllFlags::Internal_Stateful))
+        m_pattern->start_offset = 0;
+
+    size_t match_count { 0 };
+
+    MatchInput input;
+    MatchState state;
+    size_t operations = 0;
+
+    input.regex_options = m_regex_options | regex_options.value_or({}).value();
+    input.start_offset = m_pattern->start_offset;
+    size_t lines_to_skip = 0;
+
+    bool unicode = input.regex_options.has_flag_set(AllFlags::Unicode);
+    for (auto const& view : views)
+        const_cast<RegexStringView&>(view).set_unicode(unicode);
+
+    if (input.regex_options.has_flag_set(AllFlags::Internal_Stateful)) {
+        if (views.size() > 1 && input.start_offset > views.first().length()) {
+            dbgln_if(REGEX_DEBUG, "Started with start={}, goff={}, skip={}", input.start_offset, input.global_offset, lines_to_skip);
+            for (auto const& view : views) {
+                if (input.start_offset < view.length() + 1)
+                    break;
+                ++lines_to_skip;
+                input.start_offset -= view.length() + 1;
+                input.global_offset += view.length() + 1;
+            }
+            dbgln_if(REGEX_DEBUG, "Ended with start={}, goff={}, skip={}", input.start_offset, input.global_offset, lines_to_skip);
+        }
+    }
+
+    if (c_match_preallocation_count) {
+        state.matches.ensure_capacity(c_match_preallocation_count);
+        state.capture_group_matches.ensure_capacity(c_match_preallocation_count);
+        auto& capture_groups_count = m_pattern->parser_result.capture_groups_count;
+
+        for (size_t j = 0; j < c_match_preallocation_count; ++j) {
+            state.matches.empend();
+            state.capture_group_matches.empend();
+            state.capture_group_matches.mutable_at(j).ensure_capacity(capture_groups_count);
+            for (size_t k = 0; k < capture_groups_count; ++k)
+                state.capture_group_matches.mutable_at(j).unchecked_append({});
+        }
+    }
+
+    auto append_match = [](auto& input, auto& state, auto& start_position) {
+        if (state.matches.size() == input.match_index)
+            state.matches.empend();
+
+        VERIFY(start_position + state.string_position - start_position <= input.view.length());
+        if (input.regex_options.has_flag_set(AllFlags::StringCopyMatches)) {
+            state.matches.mutable_at(input.match_index) = { input.view.substring_view(start_position, state.string_position - start_position).to_byte_string(), input.line, start_position, input.global_offset + start_position };
+        } else { // let the view point to the original string ...
+            state.matches.mutable_at(input.match_index) = { input.view.substring_view(start_position, state.string_position - start_position), input.line, start_position, input.global_offset + start_position };
+        }
+    };
+
+#if REGEX_DEBUG
+    s_regex_dbg.print_header();
+#endif
+
+    bool continue_search = input.regex_options.has_flag_set(AllFlags::Global) || input.regex_options.has_flag_set(AllFlags::Multiline);
+    if (input.regex_options.has_flag_set(AllFlags::Sticky))
+        continue_search = false;
+
+    auto single_match_only = input.regex_options.has_flag_set(AllFlags::SingleMatch);
+    auto only_start_of_line = m_pattern->parser_result.optimization_data.only_start_of_line && !input.regex_options.has_flag_set(AllFlags::Multiline);
+
+    for (auto const& view : views) {
+        if (lines_to_skip != 0) {
+            ++input.line;
+            --lines_to_skip;
+            continue;
+        }
+        input.view = view;
+        dbgln_if(REGEX_DEBUG, "[match] Starting match with view ({}): _{}_", view.length(), view);
+
+        auto view_length = view.length();
+        size_t view_index = m_pattern->start_offset;
+        state.string_position = view_index;
+        state.string_position_in_code_units = view_index;
+        bool succeeded = false;
+
+        if (view_index == view_length && m_pattern->parser_result.match_length_minimum == 0) {
+            // Run the code until it tries to consume something.
+            // This allows non-consuming code to run on empty strings, for instance
+            // e.g. "Exit"
+            size_t temp_operations = operations;
+
+            input.column = match_count;
+            input.match_index = match_count;
+
+            state.string_position = view_index;
+            state.string_position_in_code_units = view_index;
+            state.instruction_position = 0;
+            state.repetition_marks.clear();
+
+            auto success = execute(input, state, temp_operations);
+            // This success is acceptable only if it doesn't read anything from the input (input length is 0).
+            if (success && (state.string_position <= view_index)) {
+                operations = temp_operations;
+                if (!match_count) {
+                    // Nothing was *actually* matched, so append an empty match.
+                    append_match(input, state, view_index);
+                    ++match_count;
+
+                    // This prevents a regex pattern like ".*" from matching the empty string
+                    // multiple times, once in this block and once in the following for loop.
+                    if (view_index == 0 && view_length == 0)
+                        ++view_index;
+                }
+            }
+        }
+
+        for (; view_index <= view_length; ++view_index) {
+            if (view_index == view_length && input.regex_options.has_flag_set(AllFlags::Multiline))
+                break;
+
+            auto& match_length_minimum = m_pattern->parser_result.match_length_minimum;
+            // FIXME: More performant would be to know the remaining minimum string
+            //        length needed to match from the current position onwards within
+            //        the vm. Add new OpCode for MinMatchLengthFromSp with the value of
+            //        the remaining string length from the current path. The value though
+            //        has to be filled in reverse. That implies a second run over bytecode
+            //        after generation has finished.
+            if (match_length_minimum && match_length_minimum > view_length - view_index)
+                break;
+
+            input.column = match_count;
+            input.match_index = match_count;
+
+            state.string_position = view_index;
+            state.string_position_in_code_units = view_index;
+            state.instruction_position = 0;
+            state.repetition_marks.clear();
+
+            auto success = execute(input, state, operations);
+            if (success) {
+                succeeded = true;
+
+                if (input.regex_options.has_flag_set(AllFlags::MatchNotEndOfLine) && state.string_position == input.view.length()) {
+                    if (!continue_search)
+                        break;
+                    continue;
+                }
+                if (input.regex_options.has_flag_set(AllFlags::MatchNotBeginOfLine) && view_index == 0) {
+                    if (!continue_search)
+                        break;
+                    continue;
+                }
+
+                dbgln_if(REGEX_DEBUG, "state.string_position={}, view_index={}", state.string_position, view_index);
+                dbgln_if(REGEX_DEBUG, "[match] Found a match (length={}): '{}'", state.string_position - view_index, input.view.substring_view(view_index, state.string_position - view_index));
+
+                ++match_count;
+
+                if (continue_search) {
+                    append_match(input, state, view_index);
+
+                    bool has_zero_length = state.string_position == view_index;
+                    view_index = state.string_position - (has_zero_length ? 0 : 1);
+                    if (single_match_only)
+                        break;
+                    continue;
+                }
+                if (input.regex_options.has_flag_set(AllFlags::Internal_Stateful)) {
+                    append_match(input, state, view_index);
+                    break;
+                }
+                if (state.string_position < view_length) {
+                    return { false, 0, {}, {}, {}, operations };
+                }
+
+                append_match(input, state, view_index);
+                break;
+            }
+
+            if (!continue_search || only_start_of_line)
+                break;
+        }
+
+        ++input.line;
+        input.global_offset += view.length() + 1; // +1 includes the line break character
+
+        if (input.regex_options.has_flag_set(AllFlags::Internal_Stateful))
+            m_pattern->start_offset = state.string_position;
+
+        if (succeeded && !continue_search)
+            break;
+    }
+
+    RegexResult result {
+        match_count != 0,
+        match_count,
+        move(state.matches).release(),
+        move(state.capture_group_matches).release(),
+        operations,
+        m_pattern->parser_result.capture_groups_count,
+        m_pattern->parser_result.named_capture_groups_count,
+    };
+
+    if (match_count) {
+        // Make sure there are as many capture matches as there are actual matches.
+        if (result.capture_group_matches.size() < match_count)
+            result.capture_group_matches.resize(match_count);
+        for (auto& matches : result.capture_group_matches)
+            matches.resize(m_pattern->parser_result.capture_groups_count + 1);
+        if (!input.regex_options.has_flag_set(AllFlags::SkipTrimEmptyMatches)) {
+            for (auto& matches : result.capture_group_matches)
+                matches.remove_all_matching([](auto& match) { return match.view.is_null(); });
+        }
+    } else {
+        result.capture_group_matches.clear_with_capacity();
+    }
+
+    return result;
+}
+
+template<typename T>
+class BumpAllocatedLinkedList {
+public:
+    BumpAllocatedLinkedList() = default;
+
+    ALWAYS_INLINE void append(T value)
+    {
+        auto node_ptr = m_allocator.allocate(move(value));
+        VERIFY(node_ptr);
+
+        if (!m_first) {
+            m_first = node_ptr;
+            m_last = node_ptr;
+            return;
+        }
+
+        node_ptr->previous = m_last;
+        m_last->next = node_ptr;
+        m_last = node_ptr;
+    }
+
+    ALWAYS_INLINE T take_last()
+    {
+        VERIFY(m_last);
+        T value = move(m_last->value);
+        if (m_last == m_first) {
+            m_last = nullptr;
+            m_first = nullptr;
+        } else {
+            m_last = m_last->previous;
+            m_last->next = nullptr;
+        }
+        return value;
+    }
+
+    ALWAYS_INLINE T& last()
+    {
+        return m_last->value;
+    }
+
+    ALWAYS_INLINE bool is_empty() const
+    {
+        return m_first == nullptr;
+    }
+
+    auto reverse_begin() { return ReverseIterator(m_last); }
+    auto reverse_end() { return ReverseIterator(); }
+
+private:
+    struct Node {
+        T value;
+        Node* next { nullptr };
+        Node* previous { nullptr };
+    };
+
+    struct ReverseIterator {
+        ReverseIterator() = default;
+        explicit ReverseIterator(Node* node)
+            : m_node(node)
+        {
+        }
+
+        T* operator->() { return &m_node->value; }
+        T& operator*() { return m_node->value; }
+        bool operator==(ReverseIterator const& it) const { return m_node == it.m_node; }
+        ReverseIterator& operator++()
+        {
+            if (m_node)
+                m_node = m_node->previous;
+            return *this;
+        }
+
+    private:
+        Node* m_node;
+    };
+
+    UniformBumpAllocator<Node, true, 2 * MiB> m_allocator;
+    Node* m_first { nullptr };
+    Node* m_last { nullptr };
+};
+
+template<class Parser>
+bool Matcher<Parser>::execute(MatchInput const& input, MatchState& state, size_t& operations) const
+{
+    if (m_pattern->parser_result.optimization_data.pure_substring_search.has_value() && input.view.is_string_view()) {
+        // Yay, we can do a simple substring search!
+        auto& needle = m_pattern->parser_result.optimization_data.pure_substring_search.value();
+        if (needle.length() + state.string_position > input.view.length())
+            return false;
+
+        auto haystack = input.view.string_view().substring_view(state.string_position);
+        if (input.regex_options.has_flag_set(AllFlags::Insensitive)) {
+            if (!haystack.substring_view(0, needle.length()).equals_ignoring_ascii_case(needle))
+                return false;
+        } else {
+            if (!haystack.starts_with(needle))
+                return false;
+        }
+
+        state.string_position += needle.length();
+        state.string_position_in_code_units += needle.length();
+        return true;
+    }
+
+    BumpAllocatedLinkedList<MatchState> states_to_try_next;
+#if REGEX_DEBUG
+    size_t recursion_level = 0;
+#endif
+
+    auto& bytecode = m_pattern->parser_result.bytecode;
+
+    for (;;) {
+        auto& opcode = bytecode.get_opcode(state);
+        ++operations;
+
+#if REGEX_DEBUG
+        s_regex_dbg.print_opcode("VM", opcode, state, recursion_level, false);
+#endif
+
+        ExecutionResult result;
+        if (input.fail_counter > 0) {
+            --input.fail_counter;
+            result = ExecutionResult::Failed_ExecuteLowPrioForks;
+        } else {
+            result = opcode.execute(input, state);
+        }
+
+#if REGEX_DEBUG
+        s_regex_dbg.print_result(opcode, bytecode, input, state, result);
+#endif
+
+        state.instruction_position += opcode.size();
+
+        switch (result) {
+        case ExecutionResult::Fork_PrioLow: {
+            bool found = false;
+            if (input.fork_to_replace.has_value()) {
+                for (auto it = states_to_try_next.reverse_begin(); it != states_to_try_next.reverse_end(); ++it) {
+                    if (it->initiating_fork == input.fork_to_replace.value()) {
+                        (*it) = state;
+                        it->instruction_position = state.fork_at_position;
+                        it->initiating_fork = *input.fork_to_replace;
+                        found = true;
+                        break;
+                    }
+                }
+                input.fork_to_replace.clear();
+            }
+            if (!found) {
+                states_to_try_next.append(state);
+                states_to_try_next.last().initiating_fork = state.instruction_position - opcode.size();
+                states_to_try_next.last().instruction_position = state.fork_at_position;
+            }
+            continue;
+        }
+        case ExecutionResult::Fork_PrioHigh: {
+            bool found = false;
+            if (input.fork_to_replace.has_value()) {
+                for (auto it = states_to_try_next.reverse_begin(); it != states_to_try_next.reverse_end(); ++it) {
+                    if (it->initiating_fork == input.fork_to_replace.value()) {
+                        (*it) = state;
+                        it->initiating_fork = *input.fork_to_replace;
+                        found = true;
+                        break;
+                    }
+                }
+                input.fork_to_replace.clear();
+            }
+            if (!found) {
+                states_to_try_next.append(state);
+                states_to_try_next.last().initiating_fork = state.instruction_position - opcode.size();
+            }
+            state.instruction_position = state.fork_at_position;
+#if REGEX_DEBUG
+            ++recursion_level;
+#endif
+            continue;
+        }
+        case ExecutionResult::Continue:
+            continue;
+        case ExecutionResult::Succeeded:
+            return true;
+        case ExecutionResult::Failed:
+            if (!states_to_try_next.is_empty()) {
+                state = states_to_try_next.take_last();
+                continue;
+            }
+            return false;
+        case ExecutionResult::Failed_ExecuteLowPrioForks: {
+            if (states_to_try_next.is_empty()) {
+                return false;
+            }
+            state = states_to_try_next.take_last();
+#if REGEX_DEBUG
+            ++recursion_level;
+#endif
+            continue;
+        }
+        }
+    }
+
+    VERIFY_NOT_REACHED();
+}
+
+template class Matcher<PosixBasicParser>;
+template class Regex<PosixBasicParser>;
+
+template class Matcher<PosixExtendedParser>;
+template class Regex<PosixExtendedParser>;
+
+template class Matcher<ECMA262Parser>;
+template class Regex<ECMA262Parser>;
+}
+
+template<typename Parser>
+struct AK::Traits<regex::CacheKey<Parser>> : public AK::DefaultTraits<regex::CacheKey<Parser>> {
+    static unsigned hash(regex::CacheKey<Parser> const& key)
+    {
+        return pair_int_hash(key.pattern.hash(), int_hash(to_underlying(key.options.value())));
+    }
+};