[experiment] add alternative wasm sqlite3 implementation available via build-tag (#2863)

This allows for building GoToSocial with [SQLite transpiled to WASM](https://github.com/ncruces/go-sqlite3) and accessed through [Wazero](https://wazero.io/).

internal/db/postgres/driver.go

@@ -0,0 +1,209 @@
+// GoToSocial
+// Copyright (C) GoToSocial Authors admin@gotosocial.org
+// SPDX-License-Identifier: AGPL-3.0-or-later
+//
+// This program is free software: you can redistribute it and/or modify
+// it under the terms of the GNU Affero General Public License as published by
+// the Free Software Foundation, either version 3 of the License, or
+// (at your option) any later version.
+//
+// This program is distributed in the hope that it will be useful,
+// but WITHOUT ANY WARRANTY; without even the implied warranty of
+// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+// GNU Affero General Public License for more details.
+//
+// You should have received a copy of the GNU Affero General Public License
+// along with this program.  If not, see <http://www.gnu.org/licenses/>.
+
+package postgres
+
+import (
+	"context"
+	"database/sql/driver"
+
+	pgx "github.com/jackc/pgx/v5/stdlib"
+	"github.com/superseriousbusiness/gotosocial/internal/db"
+)
+
+var (
+	// global PostgreSQL driver instances.
+	postgresDriver = pgx.GetDefaultDriver().(*pgx.Driver)
+
+	// check the postgres driver types
+	// conforms to our interface types.
+	// (note SQLite doesn't export their
+	// driver types, and gets checked in
+	// tests very regularly anywho).
+	_ connIface = (*pgx.Conn)(nil)
+	_ stmtIface = (*pgx.Stmt)(nil)
+	_ rowsIface = (*pgx.Rows)(nil)
+)
+
+// Driver is our own wrapper around the
+// pgx/stdlib.Driver{} type in order to wrap further
+// SQL driver types with our own err processing.
+type Driver struct{}
+
+func (d *Driver) Open(name string) (driver.Conn, error) {
+	conn, err := postgresDriver.Open(name)
+	if err != nil {
+		err = processPostgresError(err)
+		return nil, err
+	}
+	return &postgresConn{conn.(connIface)}, nil
+}
+
+func (d *Driver) OpenConnector(name string) (driver.Connector, error) {
+	cc, err := postgresDriver.OpenConnector(name)
+	if err != nil {
+		err = processPostgresError(err)
+		return nil, err
+	}
+	return &postgresConnector{driver: d, Connector: cc}, nil
+}
+
+type postgresConnector struct {
+	driver *Driver
+	driver.Connector
+}
+
+func (c *postgresConnector) Driver() driver.Driver { return c.driver }
+
+func (c *postgresConnector) Connect(ctx context.Context) (driver.Conn, error) {
+	conn, err := c.Connector.Connect(ctx)
+	if err != nil {
+		err = processPostgresError(err)
+		return nil, err
+	}
+	return &postgresConn{conn.(connIface)}, nil
+}
+
+type postgresConn struct{ connIface }
+
+func (c *postgresConn) Begin() (driver.Tx, error) {
+	return c.BeginTx(context.Background(), driver.TxOptions{})
+}
+
+func (c *postgresConn) BeginTx(ctx context.Context, opts driver.TxOptions) (driver.Tx, error) {
+	tx, err := c.connIface.BeginTx(ctx, opts)
+	err = processPostgresError(err)
+	if err != nil {
+		return nil, err
+	}
+	return &postgresTx{tx}, nil
+}
+
+func (c *postgresConn) Prepare(query string) (driver.Stmt, error) {
+	return c.PrepareContext(context.Background(), query)
+}
+
+func (c *postgresConn) PrepareContext(ctx context.Context, query string) (driver.Stmt, error) {
+	st, err := c.connIface.PrepareContext(ctx, query)
+	err = processPostgresError(err)
+	if err != nil {
+		return nil, err
+	}
+	return &postgresStmt{st.(stmtIface)}, nil
+}
+
+func (c *postgresConn) Exec(query string, args []driver.Value) (driver.Result, error) {
+	return c.ExecContext(context.Background(), query, db.ToNamedValues(args))
+}
+
+func (c *postgresConn) ExecContext(ctx context.Context, query string, args []driver.NamedValue) (driver.Result, error) {
+	result, err := c.connIface.ExecContext(ctx, query, args)
+	err = processPostgresError(err)
+	return result, err
+}
+
+func (c *postgresConn) Query(query string, args []driver.Value) (driver.Rows, error) {
+	return c.QueryContext(context.Background(), query, db.ToNamedValues(args))
+}
+
+func (c *postgresConn) QueryContext(ctx context.Context, query string, args []driver.NamedValue) (driver.Rows, error) {
+	rows, err := c.connIface.QueryContext(ctx, query, args)
+	err = processPostgresError(err)
+	if err != nil {
+		return nil, err
+	}
+	return &postgresRows{rows.(rowsIface)}, nil
+}
+
+func (c *postgresConn) Close() error {
+	err := c.connIface.Close()
+	return processPostgresError(err)
+}
+
+type postgresTx struct{ driver.Tx }
+
+func (tx *postgresTx) Commit() error {
+	err := tx.Tx.Commit()
+	return processPostgresError(err)
+}
+
+func (tx *postgresTx) Rollback() error {
+	err := tx.Tx.Rollback()
+	return processPostgresError(err)
+}
+
+type postgresStmt struct{ stmtIface }
+
+func (stmt *postgresStmt) Exec(args []driver.Value) (driver.Result, error) {
+	return stmt.ExecContext(context.Background(), db.ToNamedValues(args))
+}
+
+func (stmt *postgresStmt) ExecContext(ctx context.Context, args []driver.NamedValue) (driver.Result, error) {
+	res, err := stmt.stmtIface.ExecContext(ctx, args)
+	err = processPostgresError(err)
+	return res, err
+}
+
+func (stmt *postgresStmt) Query(args []driver.Value) (driver.Rows, error) {
+	return stmt.QueryContext(context.Background(), db.ToNamedValues(args))
+}
+
+func (stmt *postgresStmt) QueryContext(ctx context.Context, args []driver.NamedValue) (driver.Rows, error) {
+	rows, err := stmt.stmtIface.QueryContext(ctx, args)
+	err = processPostgresError(err)
+	if err != nil {
+		return nil, err
+	}
+	return &postgresRows{rows.(rowsIface)}, nil
+}
+
+type postgresRows struct{ rowsIface }
+
+func (r *postgresRows) Next(dest []driver.Value) error {
+	err := r.rowsIface.Next(dest)
+	err = processPostgresError(err)
+	return err
+}
+
+func (r *postgresRows) Close() error {
+	err := r.rowsIface.Close()
+	err = processPostgresError(err)
+	return err
+}
+
+type connIface interface {
+	driver.Conn
+	driver.ConnPrepareContext
+	driver.ExecerContext
+	driver.QueryerContext
+	driver.ConnBeginTx
+}
+
+type stmtIface interface {
+	driver.Stmt
+	driver.StmtExecContext
+	driver.StmtQueryContext
+}
+
+type rowsIface interface {
+	driver.Rows
+	driver.RowsColumnTypeDatabaseTypeName
+	driver.RowsColumnTypeLength
+	driver.RowsColumnTypePrecisionScale
+	driver.RowsColumnTypeScanType
+	driver.RowsColumnTypeScanType
+}

internal/db/postgres/errors.go

@@ -0,0 +1,46 @@
+// GoToSocial
+// Copyright (C) GoToSocial Authors admin@gotosocial.org
+// SPDX-License-Identifier: AGPL-3.0-or-later
+//
+// This program is free software: you can redistribute it and/or modify
+// it under the terms of the GNU Affero General Public License as published by
+// the Free Software Foundation, either version 3 of the License, or
+// (at your option) any later version.
+//
+// This program is distributed in the hope that it will be useful,
+// but WITHOUT ANY WARRANTY; without even the implied warranty of
+// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+// GNU Affero General Public License for more details.
+//
+// You should have received a copy of the GNU Affero General Public License
+// along with this program.  If not, see <http://www.gnu.org/licenses/>.
+
+package postgres
+
+import (
+	"fmt"
+
+	"github.com/jackc/pgx/v5/pgconn"
+	"github.com/superseriousbusiness/gotosocial/internal/db"
+)
+
+// processPostgresError processes an error, replacing any
+// postgres specific errors with our own error type
+func processPostgresError(err error) error {
+	// Attempt to cast as postgres
+	pgErr, ok := err.(*pgconn.PgError)
+	if !ok {
+		return err
+	}
+
+	// Handle supplied error code:
+	// (https://www.postgresql.org/docs/10/errcodes-appendix.html)
+	switch pgErr.Code { //nolint
+	case "23505" /* unique_violation */ :
+		return db.ErrAlreadyExists
+	}
+
+	// Wrap the returned error with the code and
+	// extended code for easier debugging later.
+	return fmt.Errorf("%w (code=%s)", err, pgErr.Code)
+}