storage: add sqlite3 (database/sql) storage support

storage/sqlite3.go

@@ -1,16 +1,149 @@
 package storage
 
-import "database/sql"
+import (
+	"database/sql"
+	"fmt"
 
-func createBlockTable(conn *sql.DB) error {
-	tableCreation := `
+	protobuf "github.com/golang/protobuf/proto"
+	"github.com/gtank/ctxd/proto"
+	"github.com/pkg/errors"
+)
+
+var (
+	ErrBadRange = errors.New("no blocks in specified range")
+)
+
+func createTables(conn *sql.DB) error {
+	stateTable := `
+		CREATE TABLE IF NOT EXISTS state (
+			current_height INTEGER,
+			timestamp DATETIME DEFAULT CURRENT_TIMESTAMP,
+			FOREIGN KEY (current_height) REFERENCES blocks (height)
+		);
+	`
+	_, err := conn.Exec(stateTable)
+	if err != nil {
+		return err
+	}
+
+	blockTable := `
 		CREATE TABLE IF NOT EXISTS blocks (
 			height INTEGER PRIMARY KEY,
 			hash TEXT,
 			has_sapling_tx BOOL,
+			encoding_version INTEGER,
 			compact_encoding BLOB
 		);
 	`
-	_, err := conn.Exec(tableCreation)
+	_, err = conn.Exec(blockTable)
+	return err
+}
+
+func CurrentHeight(conn *sql.DB) (int, error) {
+	var height int
+	query := "SELECT current_height FROM state WHERE rowid = 1"
+	err := conn.QueryRow(query).Scan(&height)
+	return height, err
+}
+
+func SetCurrentHeight(conn *sql.DB, height int) error {
+	update := "UPDATE state SET current_height=?, timestamp=CURRENT_TIMESTAMP WHERE rowid = 1"
+	result, err := conn.Exec(update, height)
+	if err != nil {
+		return errors.Wrap(err, "updating state row")
+	}
+	rowCount, err := result.RowsAffected()
+	if err != nil {
+		return errors.Wrap(err, "checking if state row exists")
+	}
+	if rowCount == 0 {
+		// row does not yet exist
+		insert := "INSERT OR IGNORE INTO state (rowid, current_height) VALUES (1, ?)"
+		result, err = conn.Exec(insert, height)
+		if err != nil {
+			return errors.Wrap(err, "on state row insert")
+		}
+		rowCount, err = result.RowsAffected()
+		if err != nil {
+			return errors.Wrap(err, "checking if state row exists")
+		}
+		if rowCount != 1 {
+			return errors.New("totally failed to update current height state")
+		}
+	}
+	return nil
+}
+
+func GetBlock(conn *sql.DB, height int) (*proto.CompactBlock, error) {
+	var blockBytes []byte // avoid a copy with *RawBytes
+	query := "SELECT compact_encoding from blocks WHERE height = ?"
+	err := conn.QueryRow(query, height).Scan(&blockBytes)
+	if err != nil {
+		return nil, err
+	}
+	compactBlock := &proto.CompactBlock{}
+	err = protobuf.Unmarshal(blockBytes, compactBlock)
+	return compactBlock, err
+}
+
+// [start, end]
+func GetBlockRange(conn *sql.DB, start, end int) ([]*proto.CompactBlock, error) {
+	// TODO sanity check range bounds
+	query := "SELECT compact_encoding from blocks WHERE (height BETWEEN ? AND ?)"
+	result, err := conn.Query(query, start, end)
+	if err != nil {
+		return nil, err
+	}
+	defer result.Close()
+
+	compactBlocks := make([]*proto.CompactBlock, 0, (end-start)+1)
+	for result.Next() {
+		var blockBytes []byte // avoid a copy with *RawBytes
+		err = result.Scan(&blockBytes)
+		if err != nil {
+			return nil, err
+		}
+		newBlock := &proto.CompactBlock{}
+		err = protobuf.Unmarshal(blockBytes, newBlock)
+		if err != nil {
+			return nil, err
+		}
+		compactBlocks = append(compactBlocks, newBlock)
+	}
+
+	err = result.Err()
+	if err != nil {
+		return nil, err
+	}
+
+	if len(compactBlocks) == 0 {
+		return nil, ErrBadRange
+	}
+	return compactBlocks, nil
+}
+
+func GetBlockByHash(conn *sql.DB, hash string) (*proto.CompactBlock, error) {
+	var blockBytes []byte // avoid a copy with *RawBytes
+	query := "SELECT compact_encoding from blocks WHERE hash = ?"
+	err := conn.QueryRow(query, hash).Scan(&blockBytes)
+	if err != nil {
+		return nil, errors.Wrap(err, fmt.Sprintf("getting block with hash %s", hash))
+	}
+	compactBlock := &proto.CompactBlock{}
+	err = protobuf.Unmarshal(blockBytes, compactBlock)
+	return compactBlock, err
+}
+
+func StoreBlock(conn *sql.DB, height int, hash string, sapling bool, version int, encoded []byte) error {
+	insertBlock := "INSERT INTO blocks (height, hash, has_sapling_tx, encoding_version, compact_encoding) values (?, ?, ?, ?, ?)"
+	_, err := conn.Exec(insertBlock, height, hash, sapling, version, encoded)
+	if err != nil {
+		return errors.Wrap(err, fmt.Sprintf("storing compact block %d", height))
+	}
+
+	currentHeight, err := CurrentHeight(conn)
+	if err != nil || height > currentHeight {
+		err = SetCurrentHeight(conn, height)
+	}
 	return err
 }