Reorganize packages

* direct_by_leaf/ is original StateDB package
* sql/ for SQL DB interfaces

sql/interfaces.go

@@ -0,0 +1,24 @@
+package sql
+
+import (
+	"context"
+)
+
+// Database interfaces to support multiple Postgres drivers
+type Database = Driver
+
+// Driver interface has all the methods required by a driver implementation to support the sql indexer
+type Driver interface {
+	QueryRow(ctx context.Context, sql string, args ...interface{}) ScannableRow
+	Exec(ctx context.Context, sql string, args ...interface{}) (Result, error)
+}
+
+// ScannableRow interface to accommodate different concrete row types
+type ScannableRow interface {
+	Scan(dest ...interface{}) error
+}
+
+// Result interface to accommodate different concrete result types
+type Result interface {
+	RowsAffected() (int64, error)
+}

sql/pgx.go

@@ -0,0 +1,41 @@
+package sql
+
+import (
+	"context"
+
+	"github.com/jackc/pgconn"
+	"github.com/jackc/pgx/v4/pgxpool"
+)
+
+var _ Driver = &PGXDriver{}
+
+// PGXDriver driver, implements Driver
+type PGXDriver struct {
+	ctx context.Context
+	db  *pgxpool.Pool
+}
+
+// NewPGXDriverFromPool returns a new pgx driver for Postgres
+func NewPGXDriverFromPool(ctx context.Context, db *pgxpool.Pool) *PGXDriver {
+	return &PGXDriver{ctx: ctx, db: db}
+}
+
+// QueryRow satisfies sql.Database
+func (driver *PGXDriver) QueryRow(ctx context.Context, sql string, args ...interface{}) ScannableRow {
+	return driver.db.QueryRow(ctx, sql, args...)
+}
+
+// Exec satisfies sql.Database
+func (pgx *PGXDriver) Exec(ctx context.Context, sql string, args ...interface{}) (Result, error) {
+	res, err := pgx.db.Exec(ctx, sql, args...)
+	return resultWrapper{ct: res}, err
+}
+
+type resultWrapper struct {
+	ct pgconn.CommandTag
+}
+
+// RowsAffected satisfies sql.Result
+func (r resultWrapper) RowsAffected() (int64, error) {
+	return r.ct.RowsAffected(), nil
+}

sql/sqlx.go

@@ -0,0 +1,30 @@
+package sql
+
+import (
+	"context"
+
+	"github.com/jmoiron/sqlx"
+)
+
+var _ Driver = &SQLXDriver{}
+
+// SQLXDriver driver, implements Driver
+type SQLXDriver struct {
+	ctx context.Context
+	db  *sqlx.DB
+}
+
+// NewSQLXDriverFromPool returns a new sqlx driver for Postgres
+func NewSQLXDriverFromPool(ctx context.Context, db *sqlx.DB) *SQLXDriver {
+	return &SQLXDriver{ctx: ctx, db: db}
+}
+
+// QueryRow satisfies sql.Database
+func (driver *SQLXDriver) QueryRow(_ context.Context, sql string, args ...interface{}) ScannableRow {
+	return driver.db.QueryRowx(sql, args...)
+}
+
+// Exec satisfies sql.Database
+func (driver *SQLXDriver) Exec(_ context.Context, sql string, args ...interface{}) (Result, error) {
+	return driver.db.Exec(sql, args...)
+}