STOR-519: Add db-connect, a SQL over HTTPS server

vendor/github.com/kshvakov/clickhouse/stmt.go

@@ -0,0 +1,185 @@
+package clickhouse
+
+import (
+	"bytes"
+	"context"
+	"database/sql/driver"
+	"unicode"
+
+	"github.com/kshvakov/clickhouse/lib/data"
+)
+
+type stmt struct {
+	ch       *clickhouse
+	query    string
+	counter  int
+	numInput int
+	isInsert bool
+}
+
+var emptyResult = &result{}
+
+func (stmt *stmt) NumInput() int {
+	switch {
+	case stmt.ch.block != nil:
+		return len(stmt.ch.block.Columns)
+	case stmt.numInput < 0:
+		return 0
+	}
+	return stmt.numInput
+}
+
+func (stmt *stmt) Exec(args []driver.Value) (driver.Result, error) {
+	return stmt.execContext(context.Background(), args)
+}
+
+func (stmt *stmt) ExecContext(ctx context.Context, args []driver.NamedValue) (driver.Result, error) {
+	dargs := make([]driver.Value, len(args))
+	for i, nv := range args {
+		dargs[i] = nv.Value
+	}
+	return stmt.execContext(ctx, dargs)
+}
+
+func (stmt *stmt) execContext(ctx context.Context, args []driver.Value) (driver.Result, error) {
+	if stmt.isInsert {
+		stmt.counter++
+		if err := stmt.ch.block.AppendRow(args); err != nil {
+			return nil, err
+		}
+		if (stmt.counter % stmt.ch.blockSize) == 0 {
+			stmt.ch.logf("[exec] flush block")
+			if err := stmt.ch.writeBlock(stmt.ch.block); err != nil {
+				return nil, err
+			}
+			if err := stmt.ch.encoder.Flush(); err != nil {
+				return nil, err
+			}
+		}
+		return emptyResult, nil
+	}
+	if err := stmt.ch.sendQuery(stmt.bind(convertOldArgs(args))); err != nil {
+		return nil, err
+	}
+	if err := stmt.ch.process(); err != nil {
+		return nil, err
+	}
+	return emptyResult, nil
+}
+
+func (stmt *stmt) Query(args []driver.Value) (driver.Rows, error) {
+	return stmt.queryContext(context.Background(), convertOldArgs(args))
+}
+
+func (stmt *stmt) QueryContext(ctx context.Context, args []driver.NamedValue) (driver.Rows, error) {
+	return stmt.queryContext(ctx, args)
+}
+
+func (stmt *stmt) queryContext(ctx context.Context, args []driver.NamedValue) (driver.Rows, error) {
+	finish := stmt.ch.watchCancel(ctx)
+	if err := stmt.ch.sendQuery(stmt.bind(args)); err != nil {
+		finish()
+		return nil, err
+	}
+	meta, err := stmt.ch.readMeta()
+	if err != nil {
+		finish()
+		return nil, err
+	}
+	rows := rows{
+		ch:           stmt.ch,
+		finish:       finish,
+		stream:       make(chan *data.Block, 50),
+		columns:      meta.ColumnNames(),
+		blockColumns: meta.Columns,
+	}
+	go rows.receiveData()
+	return &rows, nil
+}
+
+func (stmt *stmt) Close() error {
+	stmt.ch.logf("[stmt] close")
+	return nil
+}
+
+func (stmt *stmt) bind(args []driver.NamedValue) string {
+	var (
+		buf       bytes.Buffer
+		index     int
+		keyword   bool
+		inBetween bool
+		like      = newMatcher("like")
+		limit     = newMatcher("limit")
+		between   = newMatcher("between")
+		and       = newMatcher("and")
+	)
+	switch {
+	case stmt.NumInput() != 0:
+		reader := bytes.NewReader([]byte(stmt.query))
+		for {
+			if char, _, err := reader.ReadRune(); err == nil {
+				switch char {
+				case '@':
+					if param := paramParser(reader); len(param) != 0 {
+						for _, v := range args {
+							if len(v.Name) != 0 && v.Name == param {
+								buf.WriteString(quote(v.Value))
+							}
+						}
+					}
+				case '?':
+					if keyword && index < len(args) && len(args[index].Name) == 0 {
+						buf.WriteString(quote(args[index].Value))
+						index++
+					} else {
+						buf.WriteRune(char)
+					}
+				default:
+					switch {
+					case
+						char == '=',
+						char == '<',
+						char == '>',
+						char == '(',
+						char == ',',
+						char == '+',
+						char == '-',
+						char == '*',
+						char == '/',
+						char == '[':
+						keyword = true
+					default:
+						if limit.matchRune(char) || like.matchRune(char) {
+							keyword = true
+						} else if between.matchRune(char) {
+							keyword = true
+							inBetween = true
+						} else if inBetween && and.matchRune(char) {
+							keyword = true
+							inBetween = false
+						} else {
+							keyword = keyword && unicode.IsSpace(char)
+						}
+					}
+					buf.WriteRune(char)
+				}
+			} else {
+				break
+			}
+		}
+	default:
+		buf.WriteString(stmt.query)
+	}
+	return buf.String()
+}
+
+func convertOldArgs(args []driver.Value) []driver.NamedValue {
+	dargs := make([]driver.NamedValue, len(args))
+	for i, v := range args {
+		dargs[i] = driver.NamedValue{
+			Ordinal: i + 1,
+			Value:   v,
+		}
+	}
+	return dargs
+}