Add named parameters support

sqlite.go

@@ -2,8 +2,6 @@
 // Use of this source code is governed by a BSD-style
 // license that can be found in the LICENSE file.
 
-//TODO Pinger (tags go1.8)
-
 //go:generate go run generator.go
 
 // Package sqlite is an in-process implementation of a self-contained,
@@ -66,6 +64,7 @@ import (
 	"github.com/cznic/sqlite/internal/bin"
 	"github.com/cznic/virtual"
 	"github.com/cznic/xc"
+	"golang.org/x/net/context"
 )
 
 var (
@@ -101,6 +100,7 @@ var (
 	bindInt             int
 	bindInt64           int
 	bindParameterCount  int
+	bindParameterName   int
 	bindText            int
 	changes             int
 	closeV2             int
@@ -118,6 +118,7 @@ var (
 	extendedResultCodes int
 	finalize            int
 	free                int
+	interrupt           int
 	lastInsertRowID     int
 	maloc               int
 	openV2              int
@@ -159,6 +160,7 @@ func init() {
 		{&bindInt, "sqlite3_bind_int"},
 		{&bindInt64, "sqlite3_bind_int64"},
 		{&bindParameterCount, "sqlite3_bind_parameter_count"},
+		{&bindParameterName, "sqlite3_bind_parameter_name"},
 		{&bindText, "sqlite3_bind_text"},
 		{&changes, "sqlite3_changes"},
 		{&closeV2, "sqlite3_close_v2"},
@@ -176,6 +178,7 @@ func init() {
 		{&extendedResultCodes, "sqlite3_extended_result_codes"},
 		{&finalize, "sqlite3_finalize"},
 		{&free, "sqlite3_free"},
+		{&interrupt, "sqlite3_interrupt"},
 		{&lastInsertRowID, "sqlite3_last_insert_rowid"},
 		{&maloc, "sqlite3_malloc"},
 		{&openV2, "sqlite3_open_v2"},
@@ -599,21 +602,37 @@ func (s *stmt) NumInput() (n int) {
 }
 
 // Exec executes a query that doesn't return rows, such as an INSERT or UPDATE.
-//
-// Deprecated: Drivers should implement StmtExecContext instead (or
-// additionally).
-func (s *stmt) Exec(args []driver.Value) (r driver.Result, err error) {
+func (s *stmt) Exec(args []driver.Value) (driver.Result, error) {
+	return s.exec(context.Background(), toNamedValues(args))
+}
+
+func (s *stmt) exec(ctx context.Context, args []namedValue) (r driver.Result, err error) {
 	if trace {
-		defer func(args []driver.Value) {
+		defer func(args []namedValue) {
 			tracer(s, "Exec(%v): (%v, %v)", args, r, err)
 		}(args)
 	}
+
+	var pstmt uintptr
+
+	donech := make(chan struct{})
+	defer close(donech)
+	go func() {
+		select {
+		case <-ctx.Done():
+			if pstmt != 0 {
+				s.interrupt(s.pdb())
+			}
+		case <-donech:
+		}
+	}()
+
 	for psql := s.psql; readI8(psql) != 0; psql = readPtr(s.pzTail) {
 		if err := s.prepareV2(psql); err != nil {
 			return nil, err
 		}
 
-		pstmt := readPtr(s.ppstmt)
+		pstmt = readPtr(s.ppstmt)
 		if pstmt == 0 {
 			continue
 		}
@@ -627,9 +646,8 @@ func (s *stmt) Exec(args []driver.Value) (r driver.Result, err error) {
 			if err = s.bind(pstmt, n, args); err != nil {
 				return nil, err
 			}
-
-			args = args[n:]
 		}
+
 		rc, err := s.step(pstmt)
 		if err != nil {
 			s.finalize(pstmt)
@@ -650,24 +668,39 @@ func (s *stmt) Exec(args []driver.Value) (r driver.Result, err error) {
 	return newResult(s)
 }
 
-// Query executes a query that may return rows, such as a SELECT.
-//
-// Deprecated: Drivers should implement StmtQueryContext instead (or
-// additionally).
-func (s *stmt) Query(args []driver.Value) (r driver.Rows, err error) {
+func (s *stmt) Query(args []driver.Value) (driver.Rows, error) {
+	return s.query(context.Background(), toNamedValues(args))
+}
+
+func (s *stmt) query(ctx context.Context, args []namedValue) (r driver.Rows, err error) {
 	if trace {
-		defer func(args []driver.Value) {
+		defer func(args []namedValue) {
 			tracer(s, "Query(%v): (%v, %v)", args, r, err)
 		}(args)
 	}
+
+	var pstmt uintptr
 	var rowStmt uintptr
 	var rc0 int
+
+	donech := make(chan struct{})
+	defer close(donech)
+	go func() {
+		select {
+		case <-ctx.Done():
+			if pstmt != 0 {
+				s.interrupt(s.pdb())
+			}
+		case <-donech:
+		}
+	}()
+
 	for psql := s.psql; readI8(psql) != 0; psql = readPtr(s.pzTail) {
 		if err := s.prepareV2(psql); err != nil {
 			return nil, err
 		}
 
-		pstmt := readPtr(s.ppstmt)
+		pstmt = readPtr(s.ppstmt)
 		if pstmt == 0 {
 			continue
 		}
@@ -681,9 +714,8 @@ func (s *stmt) Query(args []driver.Value) (r driver.Rows, err error) {
 			if err = s.bind(pstmt, n, args); err != nil {
 				return nil, err
 			}
-
-			args = args[n:]
 		}
+
 		rc, err := s.step(pstmt)
 		if err != nil {
 			s.finalize(pstmt)
@@ -818,19 +850,46 @@ func (s *stmt) bindText(pstmt uintptr, idx1 int, value string) (err error) {
 	return nil
 }
 
-func (s *stmt) bind(pstmt uintptr, n int, args []driver.Value) error {
-	if len(args) < n {
-		return fmt.Errorf("missing arguments: got %v, expected %v", len(args), n)
-	}
+func (s *stmt) bind(pstmt uintptr, n int, args []namedValue) error {
+	for i := 1; i <= n; i++ {
+		name, err := s.bindParameterName(pstmt, i)
+		if err != nil {
+			return err
+		}
 
-	for i, v := range args[:n] {
-		switch x := v.(type) {
+		var v namedValue
+		for _, v = range args {
+			if name != "" {
+				// sqlite supports '$', '@' and ':' prefixes for string
+				// identifiers and '?' for numeric, so we cannot
+				// combine different prefixes with the same name
+				// because `database/sql` requires variable names
+				// to start with a letter
+				if name[1:] == v.Name[:] {
+					break
+				}
+			} else {
+				if v.Ordinal == i {
+					break
+				}
+			}
+		}
+
+		if v.Ordinal == 0 {
+			if name != "" {
+				return fmt.Errorf("missing named argument %q", name[1:])
+			} else {
+				return fmt.Errorf("missing argument with %d index", i)
+			}
+		}
+
+		switch x := v.Value.(type) {
 		case int64:
-			if err := s.bindInt64(pstmt, i+1, x); err != nil {
+			if err := s.bindInt64(pstmt, i, x); err != nil {
 				return err
 			}
 		case float64:
-			if err := s.bindDouble(pstmt, i+1, x); err != nil {
+			if err := s.bindDouble(pstmt, i, x); err != nil {
 				return err
 			}
 		case bool:
@@ -838,19 +897,19 @@ func (s *stmt) bind(pstmt uintptr, n int, args []driver.Value) error {
 			if x {
 				v = 1
 			}
-			if err := s.bindInt(pstmt, i+1, v); err != nil {
+			if err := s.bindInt(pstmt, i, v); err != nil {
 				return err
 			}
 		case []byte:
-			if err := s.bindBlob(pstmt, i+1, x); err != nil {
+			if err := s.bindBlob(pstmt, i, x); err != nil {
 				return err
 			}
 		case string:
-			if err := s.bindText(pstmt, i+1, x); err != nil {
+			if err := s.bindText(pstmt, i, x); err != nil {
 				return err
 			}
 		case time.Time:
-			if err := s.bindText(pstmt, i+1, x.String()); err != nil {
+			if err := s.bindText(pstmt, i, x.String()); err != nil {
 				return err
 			}
 		default:
@@ -871,6 +930,18 @@ func (s *stmt) bindParameterCount(pstmt uintptr) (_ int, err error) {
 	return int(r), err
 }
 
+// const char *sqlite3_bind_parameter_name(sqlite3_stmt*, int);
+func (s *stmt) bindParameterName(pstmt uintptr, i int) (string, error) {
+	var p uintptr
+	_, err := s.FFI1(
+		bindParameterName,
+		virtual.PtrResult{&p},
+		virtual.Ptr(pstmt),
+		virtual.Int32(i),
+	)
+	return virtual.GoString(p), err
+}
+
 // int sqlite3_finalize(sqlite3_stmt *pStmt);
 func (s *stmt) finalize(pstmt uintptr) error {
 	var rc int32
@@ -932,7 +1003,7 @@ func (t *tx) String() string { return fmt.Sprintf("&%T@%p{conn: %p}", *t, t, t.c
 
 func newTx(c *conn) (*tx, error) {
 	t := &tx{conn: c}
-	if err := t.exec("begin"); err != nil {
+	if err := t.exec(context.Background(), "begin"); err != nil {
 		return nil, err
 	}
 
@@ -946,7 +1017,7 @@ func (t *tx) Commit() (err error) {
 			tracer(t, "Commit(): %v", err)
 		}()
 	}
-	return t.exec("commit")
+	return t.exec(context.Background(), "commit")
 }
 
 // Rollback implements driver.Tx.
@@ -956,7 +1027,7 @@ func (t *tx) Rollback() (err error) {
 			tracer(t, "Rollback(): %v", err)
 		}()
 	}
-	return t.exec("rollback")
+	return t.exec(context.Background(), "rollback")
 }
 
 // int sqlite3_exec(
@@ -966,7 +1037,7 @@ func (t *tx) Rollback() (err error) {
 //   void *,                                    /* 1st argument to callback */
 //   char **errmsg                              /* Error msg written here */
 // );
-func (t *tx) exec(sql string) (err error) {
+func (t *tx) exec(ctx context.Context, sql string) (err error) {
 	psql, err := t.cString(sql)
 	if err != nil {
 		return err
@@ -974,6 +1045,17 @@ func (t *tx) exec(sql string) (err error) {
 
 	defer t.free(psql)
 
+	// TODO: use t.conn.ExecContext() instead
+	donech := make(chan struct{})
+	defer close(donech)
+	go func() {
+		select {
+		case <-ctx.Done():
+			t.interrupt(t.pdb())
+		case <-donech:
+		}
+	}()
+
 	var rc int32
 	if _, err = t.FFI1(
 		exec,
@@ -1049,6 +1131,10 @@ func newConn(s *Driver, name string) (_ *conn, err error) {
 
 // Prepare returns a prepared statement, bound to this connection.
 func (c *conn) Prepare(query string) (s driver.Stmt, err error) {
+	return c.prepare(context.Background(), query)
+}
+
+func (c *conn) prepare(ctx context.Context, query string) (s driver.Stmt, err error) {
 	if trace {
 		defer func() {
 			tracer(c, "Prepare(%s): (%v, %v)", query, s, err)
@@ -1072,13 +1158,21 @@ func (c *conn) Close() (err error) {
 	return c.close()
 }
 
-// Begin starts and returns a new transaction.
-//
-// Deprecated: Drivers should implement ConnBeginTx instead (or additionally).
-func (c *conn) Begin() (t driver.Tx, err error) {
+// Begin starts a transaction.
+func (c *conn) Begin() (driver.Tx, error) {
+	return c.begin(context.Background(), txOptions{})
+}
+
+// copy of driver.TxOptions
+type txOptions struct {
+	Isolation int // driver.IsolationLevel
+	ReadOnly  bool
+}
+
+func (c *conn) begin(ctx context.Context, opts txOptions) (t driver.Tx, err error) {
 	if trace {
 		defer func() {
-			tracer(c, "Begin(): (%v, %v)", t, err)
+			tracer(c, "BeginTx(): (%v, %v)", t, err)
 		}()
 	}
 	return newTx(c)
@@ -1090,16 +1184,18 @@ func (c *conn) Begin() (t driver.Tx, err error) {
 // prepare a query, execute the statement, and then close the statement.
 //
 // Exec may return ErrSkip.
-//
-// Deprecated: Drivers should implement ExecerContext instead (or
-// additionally).
-func (c *conn) Exec(query string, args []driver.Value) (r driver.Result, err error) {
+func (c *conn) Exec(query string, args []driver.Value) (driver.Result, error) {
+	return c.exec(context.Background(), query, toNamedValues(args))
+}
+
+func (c *conn) exec(ctx context.Context, query string, args []namedValue) (r driver.Result, err error) {
 	if trace {
 		defer func() {
-			tracer(c, "Exec(%s, %v): (%v, %v)", query, args, r, err)
+			tracer(c, "ExecContext(%s, %v): (%v, %v)", query, args, r, err)
 		}()
 	}
-	s, err := c.Prepare(query)
+
+	s, err := c.PrepareContext(ctx, query)
 	if err != nil {
 		return nil, err
 	}
@@ -1110,7 +1206,23 @@ func (c *conn) Exec(query string, args []driver.Value) (r driver.Result, err err
 		}
 	}()
 
-	return s.Exec(args)
+	return s.(*stmt).exec(ctx, args)
+}
+
+// copy of driver.NameValue
+type namedValue struct {
+	Name    string
+	Ordinal int
+	Value   driver.Value
+}
+
+// toNamedValues converts []driver.Value to []namedValue
+func toNamedValues(vals []driver.Value) []namedValue {
+	args := make([]namedValue, 0, len(vals))
+	for i, val := range vals {
+		args = append(args, namedValue{Value: val, Ordinal: i + 1})
+	}
+	return args
 }
 
 // Queryer is an optional interface that may be implemented by a Conn.
@@ -1119,16 +1231,17 @@ func (c *conn) Exec(query string, args []driver.Value) (r driver.Result, err err
 // prepare a query, execute the statement, and then close the statement.
 //
 // Query may return ErrSkip.
-//
-// Deprecated: Drivers should implement QueryerContext instead (or
-// additionally).
-func (c *conn) Query(query string, args []driver.Value) (r driver.Rows, err error) {
+func (c *conn) Query(query string, args []driver.Value) (driver.Rows, error) {
+	return c.query(context.Background(), query, toNamedValues(args))
+}
+
+func (c *conn) query(ctx context.Context, query string, args []namedValue) (r driver.Rows, err error) {
 	if trace {
 		defer func() {
 			tracer(c, "Query(%s, %v): (%v, %v)", query, args, r, err)
 		}()
 	}
-	s, err := c.Prepare(query)
+	s, err := c.PrepareContext(ctx, query)
 	if err != nil {
 		return nil, err
 	}
@@ -1139,7 +1252,7 @@ func (c *conn) Query(query string, args []driver.Value) (r driver.Rows, err erro
 		}
 	}()
 
-	return s.Query(args)
+	return s.(*stmt).query(ctx, args)
 }
 
 func (c *conn) pdb() uintptr { return readPtr(c.ppdb) }
@@ -1278,6 +1391,15 @@ func (c *conn) free(p uintptr) (err error) {
 	return err
 }
 
+// void sqlite3_interrupt(sqlite3*);
+func (c *conn) interrupt(pdb uintptr) (err error) {
+	_, err = c.FFI0(
+		interrupt,
+		virtual.Ptr(pdb),
+	)
+	return err
+}
+
 func (c *conn) close() (err error) {
 	c.Lock()