conn.go

//
// Copyright 2017, TCN Inc.
// All rights reserved.
//
// Redistribution and use in source and binary forms, with or without
// modification, are permitted provided that the following conditions are
// met:
//
//     * Redistributions of source code must retain the above copyright
// notice, this list of conditions and the following disclaimer.
//     * Redistributions in binary form must reproduce the above
// copyright notice, this list of conditions and the following disclaimer
// in the documentation and/or other materials provided with the
// distribution.
//     * Neither the name of TCN Inc. nor the names of its
// contributors may be used to endorse or promote products derived from
// this software without specific prior written permission.
//
// THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
// "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
// LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
// A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
// OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
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// LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
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// THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
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// OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.

package sqlspanner

import (
	"cloud.google.com/go/spanner"
	"context"
	"database/sql/driver"
)

type conn struct {
	ctx    context.Context
	client *spanner.Client
}

func (c *conn) Prepare(query string) (driver.Stmt, error) {
	return newStmt(query, c)
}

func (c *conn) Close() error {
	if c.client != nil {
		c.client.Close()
	}
	return nil
}

func (c *conn) Begin() (driver.Tx, error) {
	return newTransaction(context.Background(), c, nil)
}

func (c *conn) BeginTx(ctx context.Context, opts driver.TxOptions) (driver.Tx, error) {
	return newTransaction(ctx, c, &opts)
}

func (c *conn) Ping(ctx context.Context) error {
	stmt := spanner.Statement{SQL: "SELECT 1"}
	iter := c.client.Single().Query(c.ctx, stmt)
	defer iter.Stop()
	row, err := iter.Next()
	if err != nil {
		return driver.ErrBadConn
	}

	var i int64
	if row.Columns(&i) != nil {
		return driver.ErrBadConn
	}
	return nil
}