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#include "lexer.h"
#include "regex.h"
#include <contrib/libs/re2/re2/re2.h>
#include <yql/essentials/core/issue/yql_issue.h>
#include <yql/essentials/sql/v1/reflect/sql_reflect.h>
#include <util/generic/algorithm.h>
#include <util/generic/string.h>
#include <util/string/subst.h>
#include <util/string/ascii.h>
namespace NSQLTranslationV1 {
using NSQLTranslation::TParsedToken;
using NSQLTranslation::TParsedTokenList;
class TRegexLexer: public NSQLTranslation::ILexer {
static constexpr const char* CommentTokenName = "COMMENT";
public:
TRegexLexer(
bool ansi,
NSQLReflect::TLexerGrammar grammar,
const TVector<std::tuple<TString, TString>>& RegexByOtherName)
: Grammar_(std::move(grammar))
, Ansi_(ansi)
{
for (const auto& [token, regex] : RegexByOtherName) {
if (token == CommentTokenName) {
CommentRegex_.Reset(new RE2(regex));
} else {
OtherRegexes_.emplace_back(token, new RE2(regex));
}
}
}
bool Tokenize(
const TString& query,
const TString& queryName,
const TTokenCallback& onNextToken,
NYql::TIssues& issues,
size_t maxErrors) override {
size_t errors = 0;
for (size_t pos = 0; pos < query.size();) {
TParsedToken matched = Match(TStringBuf(query, pos));
if (matched.Name.empty() && maxErrors == errors) {
break;
}
if (matched.Name.empty()) {
pos += 1;
errors += 1;
issues.AddIssue(NYql::TPosition(pos, 0, queryName), "no candidates");
continue;
}
pos += matched.Content.length();
onNextToken(std::move(matched));
}
onNextToken(TParsedToken{.Name = "EOF"});
return errors == 0;
}
private:
TParsedToken Match(const TStringBuf prefix) {
TParsedTokenList matches;
size_t keywordCount = MatchKeyword(prefix, matches);
MatchPunctuation(prefix, matches);
MatchRegex(prefix, matches);
MatchComment(prefix, matches);
if (matches.empty()) {
return {};
}
auto maxLength = MaxElementBy(matches, [](const TParsedToken& m) {
return m.Content.length();
})->Content.length();
auto max = FindIf(matches, [&](const TParsedToken& m) {
return m.Content.length() == maxLength;
});
auto isMatched = [&](const TStringBuf name) {
return std::end(matches) != FindIf(matches, [&](const auto& m) {
return m.Name == name;
});
};
size_t conflicts = CountIf(matches, [&](const TParsedToken& m) {
return m.Content.length() == max->Content.length();
});
conflicts -= 1;
Y_ENSURE(
conflicts == 0 ||
(conflicts == 1 && keywordCount != 0 && isMatched("ID_PLAIN")) ||
(conflicts == 1 && isMatched("DIGITS") && isMatched("INTEGER_VALUE")));
Y_ENSURE(!max->Content.empty());
return *max;
}
bool MatchKeyword(const TStringBuf prefix, TParsedTokenList& matches) {
size_t count = 0;
for (const auto& keyword : Grammar_.KeywordNames) {
const TStringBuf content = prefix.substr(0, keyword.length());
if (AsciiEqualsIgnoreCase(content, keyword)) {
matches.emplace_back(keyword, TString(content));
count += 1;
}
}
return count;
}
size_t MatchPunctuation(const TStringBuf prefix, TParsedTokenList& matches) {
size_t count = 0;
for (const auto& name : Grammar_.PunctuationNames) {
const auto& content = Grammar_.BlockByName.at(name);
if (prefix.substr(0, content.length()) == content) {
matches.emplace_back(name, content);
count += 1;
}
}
return count;
}
size_t MatchRegex(const TStringBuf prefix, TParsedTokenList& matches) {
size_t count = 0;
for (const auto& [token, regex] : OtherRegexes_) {
if (const TStringBuf match = TryMatchRegex(prefix, *regex); !match.empty()) {
matches.emplace_back(token, TString(match));
count += 1;
}
}
return count;
}
const TStringBuf TryMatchRegex(const TStringBuf prefix, const RE2& regex) {
re2::StringPiece input(prefix.data(), prefix.size());
if (RE2::Consume(&input, regex)) {
return TStringBuf(prefix.data(), input.data());
}
return "";
}
size_t MatchComment(const TStringBuf prefix, TParsedTokenList& matches) {
const TStringBuf reContent = TryMatchRegex(prefix, *CommentRegex_);
if (reContent.empty()) {
return 0;
}
if (!(Ansi_ && prefix.StartsWith("/*"))) {
matches.emplace_back(CommentTokenName, TString(reContent));
return 1;
}
size_t ll1Length = MatchANSIMultilineComment(prefix);
const TStringBuf ll1Content = prefix.SubString(0, ll1Length);
Y_ENSURE(ll1Content == 0 || reContent <= ll1Content);
if (ll1Content == 0) {
matches.emplace_back(CommentTokenName, TString(reContent));
return 1;
}
matches.emplace_back(CommentTokenName, TString(ll1Content));
return 1;
}
size_t MatchANSIMultilineComment(TStringBuf remaining) {
if (!remaining.StartsWith("/*")) {
return 0;
}
size_t skipped = 0;
remaining.Skip(2);
skipped += 2;
for (;;) {
if (remaining.StartsWith("*/")) {
remaining.Skip(2);
skipped += 2;
return skipped;
}
bool isSkipped = false;
if (remaining.StartsWith("/*")) {
size_t limit = remaining.rfind("*/");
if (limit == std::string::npos) {
return 0;
}
size_t len = MatchANSIMultilineComment(remaining.Head(limit));
remaining.Skip(len);
skipped += len;
isSkipped = len != 0;
}
if (isSkipped) {
continue;
}
if (remaining.size() == 0) {
return 0;
}
remaining.Skip(1);
skipped += 1;
}
}
NSQLReflect::TLexerGrammar Grammar_;
TVector<std::tuple<TString, THolder<RE2>>> OtherRegexes_;
THolder<RE2> CommentRegex_;
bool Ansi_;
};
namespace {
class TFactory final: public NSQLTranslation::ILexerFactory {
public:
explicit TFactory(bool ansi)
: Ansi_(ansi)
, Grammar_(NSQLReflect::LoadLexerGrammar())
, RegexByOtherName_(MakeRegexByOtherName(Grammar_, Ansi_))
{
}
NSQLTranslation::ILexer::TPtr MakeLexer() const override {
return NSQLTranslation::ILexer::TPtr(
new TRegexLexer(Ansi_, Grammar_, RegexByOtherName_));
}
private:
bool Ansi_;
NSQLReflect::TLexerGrammar Grammar_;
TVector<std::tuple<TString, TString>> RegexByOtherName_;
};
} // namespace
NSQLTranslation::TLexerFactoryPtr MakeRegexLexerFactory(bool ansi) {
return NSQLTranslation::TLexerFactoryPtr(new TFactory(ansi));
}
} // namespace NSQLTranslationV1
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