YQL-19747 Complete folder, table and cluster names

---

- Related to `YQL-19747`
- On top of https://github.com/ytsaurus/ytsaurus/pull/1253
- Related to https://github.com/ydb-platform/ydb/issues/9056
- Related to https://github.com/vityaman/ydb/issues/14
- Related to https://github.com/vityaman/ydb/issues/35
- Related to https://github.com/vityaman/ydb/issues/40

---

Pull Request resolved: https://github.com/ytsaurus/ytsaurus/pull/1257
commit_hash:0b842abb27184c88b8177beeea29fb1ea86b7a04

1 files changed, 160 insertions, 0 deletions

diff --git a/yql/essentials/sql/v1/complete/syntax/cursor_token_context.cpp b/yql/essentials/sql/v1/complete/syntax/cursor_token_context.cpp
new file mode 100644
index 00000000000..33aef36847a
--- /dev/null
+++ b/yql/essentials/sql/v1/complete/syntax/cursor_token_context.cpp
@@ -0,0 +1,160 @@
+#include "cursor_token_context.h"
+
+#include <yql/essentials/core/issue/yql_issue.h>
+#include <yql/essentials/sql/v1/lexer/lexer.h>
+
+namespace NSQLComplete {
+
+    namespace {
+
+        bool Tokenize(ILexer::TPtr& lexer, TCompletionInput input, TParsedTokenList& tokens) {
+            NYql::TIssues issues;
+            if (!NSQLTranslation::Tokenize(
+                    *lexer, TString(input.Text), /* queryName = */ "",
+                    tokens, issues, /* maxErrors = */ 1)) {
+                return false;
+            }
+            return true;
+        }
+
+        TCursor GetCursor(const TParsedTokenList& tokens, size_t cursorPosition) {
+            size_t current = 0;
+            for (size_t i = 0; i < tokens.size() && current < cursorPosition; ++i) {
+                const auto& content = tokens[i].Content;
+
+                current += content.size();
+                if (current < cursorPosition) {
+                    continue;
+                }
+
+                TCursor cursor = {
+                    .PrevTokenIndex = i,
+                    .NextTokenIndex = i,
+                    .Position = cursorPosition,
+                };
+
+                if (current == cursorPosition) {
+                    cursor.NextTokenIndex += 1;
+                }
+
+                return cursor;
+            }
+
+            return {
+                .PrevTokenIndex = Nothing(),
+                .NextTokenIndex = 0,
+                .Position = cursorPosition,
+            };
+        }
+
+        TVector<size_t> GetTokenPositions(const TParsedTokenList& tokens) {
+            TVector<size_t> positions;
+            positions.reserve(tokens.size());
+            size_t pos = 0;
+            for (const auto& token : tokens) {
+                positions.emplace_back(pos);
+                pos += token.Content.size();
+            }
+            return positions;
+        }
+
+    } // namespace
+
+    bool TRichParsedToken::IsLiteral() const {
+        return Base->Name == "STRING_VALUE" ||
+               Base->Name == "DIGIGTS" ||
+               Base->Name == "INTEGER_VALUE" ||
+               Base->Name == "REAL";
+    }
+
+    TRichParsedToken TokenAt(const TCursorTokenContext& context, size_t index) {
+        return {
+            .Base = &context.Tokens.at(index),
+            .Index = index,
+            .Position = context.TokenPositions.at(index),
+        };
+    }
+
+    TMaybe<TRichParsedToken> TCursorTokenContext::Enclosing() const {
+        if (Tokens.size() == 1) {
+            Y_ENSURE(Tokens[0].Name == "EOF");
+            return Nothing();
+        }
+
+        if (Cursor.PrevTokenIndex.Empty()) {
+            return Nothing();
+        }
+
+        auto token = TokenAt(*this, *Cursor.PrevTokenIndex);
+        if (Cursor.PrevTokenIndex == Cursor.NextTokenIndex ||
+            !IsWordBoundary(token.Base->Content.back())) {
+            return token;
+        }
+
+        return Nothing();
+    }
+
+    TMaybe<TRichParsedToken> TCursorTokenContext::MatchCursorPrefix(const TVector<TStringBuf>& pattern) const {
+        const auto prefix = std::span{Tokens.begin(), Cursor.NextTokenIndex};
+        if (prefix.size() < pattern.size()) {
+            return Nothing();
+        }
+
+        ssize_t i = static_cast<ssize_t>(prefix.size()) - 1;
+        ssize_t j = static_cast<ssize_t>(pattern.size()) - 1;
+        for (; 0 <= j; --i, --j) {
+            if (!pattern[j].empty() && prefix[i].Name != pattern[j]) {
+                return Nothing();
+            }
+        }
+        return TokenAt(*this, prefix.size() - pattern.size());
+    }
+
+    bool GetStatement(
+        ILexer::TPtr& lexer,
+        TCompletionInput input,
+        TCompletionInput& output,
+        size_t& output_position) {
+        TVector<TString> statements;
+        NYql::TIssues issues;
+        if (!NSQLTranslationV1::SplitQueryToStatements(
+                TString(input.Text) + ";", lexer,
+                statements, issues, /* file = */ "",
+                /* areBlankSkipped = */ false)) {
+            return false;
+        }
+
+        size_t& cursor = output_position;
+        cursor = 0;
+        for (const auto& statement : statements) {
+            if (input.CursorPosition < cursor + statement.size()) {
+                output = {
+                    .Text = input.Text.SubStr(cursor, statement.size()),
+                    .CursorPosition = input.CursorPosition - cursor,
+                };
+                return true;
+            }
+            cursor += statement.size();
+        }
+
+        output = input;
+        return true;
+    }
+
+    bool GetCursorTokenContext(ILexer::TPtr& lexer, TCompletionInput input, TCursorTokenContext& context) {
+        TParsedTokenList tokens;
+        if (!Tokenize(lexer, input, tokens)) {
+            return false;
+        }
+
+        TVector<size_t> positions = GetTokenPositions(tokens);
+        TCursor cursor = GetCursor(tokens, input.CursorPosition);
+        context = {
+            .Tokens = std::move(tokens),
+            .TokenPositions = std::move(positions),
+            .Cursor = cursor,
+        };
+        return true;
+    }
+
+} // namespace NSQLComplete