1 files changed, 42 insertions, 8 deletions

diff --git a/src/pkg/database/sql/fakedb_test.go b/src/pkg/database/sql/fakedb_test.go
index d900e2ceb..a8adfdd94 100644
--- a/src/pkg/database/sql/fakedb_test.go
+++ b/src/pkg/database/sql/fakedb_test.go
@@ -38,6 +38,8 @@ type fakeDriver struct {
 	mu         sync.Mutex // guards 3 following fields
 	openCount  int        // conn opens
 	closeCount int        // conn closes
+	waitCh     chan struct{}
+	waitingCh  chan struct{}
 	dbs        map[string]*fakeDB
 }
 
@@ -146,6 +148,12 @@ func (d *fakeDriver) Open(dsn string) (driver.Conn, error) {
 	if len(parts) >= 2 && parts[1] == "badConn" {
 		conn.bad = true
 	}
+	if d.waitCh != nil {
+		d.waitingCh <- struct{}{}
+		<-d.waitCh
+		d.waitCh = nil
+		d.waitingCh = nil
+	}
 	return conn, nil
 }
 
@@ -447,6 +455,10 @@ func (c *fakeConn) Prepare(query string) (driver.Stmt, error) {
 		return c.prepareCreate(stmt, parts)
 	case "INSERT":
 		return c.prepareInsert(stmt, parts)
+	case "NOSERT":
+		// Do all the prep-work like for an INSERT but don't actually insert the row.
+		// Used for some of the concurrent tests.
+		return c.prepareInsert(stmt, parts)
 	default:
 		stmt.Close()
 		return nil, errf("unsupported command type %q", cmd)
@@ -497,13 +509,20 @@ func (s *fakeStmt) Exec(args []driver.Value) (driver.Result, error) {
 		}
 		return driver.ResultNoRows, nil
 	case "INSERT":
-		return s.execInsert(args)
+		return s.execInsert(args, true)
+	case "NOSERT":
+		// Do all the prep-work like for an INSERT but don't actually insert the row.
+		// Used for some of the concurrent tests.
+		return s.execInsert(args, false)
 	}
 	fmt.Printf("EXEC statement, cmd=%q: %#v\n", s.cmd, s)
 	return nil, fmt.Errorf("unimplemented statement Exec command type of %q", s.cmd)
 }
 
-func (s *fakeStmt) execInsert(args []driver.Value) (driver.Result, error) {
+// When doInsert is true, add the row to the table.
+// When doInsert is false do prep-work and error checking, but don't
+// actually add the row to the table.
+func (s *fakeStmt) execInsert(args []driver.Value, doInsert bool) (driver.Result, error) {
 	db := s.c.db
 	if len(args) != s.placeholders {
 		panic("error in pkg db; should only get here if size is correct")
@@ -518,7 +537,10 @@ func (s *fakeStmt) execInsert(args []driver.Value) (driver.Result, error) {
 	t.mu.Lock()
 	defer t.mu.Unlock()
 
-	cols := make([]interface{}, len(t.colname))
+	var cols []interface{}
+	if doInsert {
+		cols = make([]interface{}, len(t.colname))
+	}
 	argPos := 0
 	for n, colname := range s.colName {
 		colidx := t.columnIndex(colname)
@@ -532,10 +554,14 @@ func (s *fakeStmt) execInsert(args []driver.Value) (driver.Result, error) {
 		} else {
 			val = s.colValue[n]
 		}
-		cols[colidx] = val
+		if doInsert {
+			cols[colidx] = val
+		}
 	}
 
-	t.rows = append(t.rows, &row{cols: cols})
+	if doInsert {
+		t.rows = append(t.rows, &row{cols: cols})
+	}
 	return driver.RowsAffected(1), nil
 }
 
@@ -608,9 +634,10 @@ rows:
 	}
 
 	cursor := &rowsCursor{
-		pos:  -1,
-		rows: mrows,
-		cols: s.colName,
+		pos:    -1,
+		rows:   mrows,
+		cols:   s.colName,
+		errPos: -1,
 	}
 	return cursor, nil
 }
@@ -635,6 +662,10 @@ type rowsCursor struct {
 	rows   []*row
 	closed bool
 
+	// errPos and err are for making Next return early with error.
+	errPos int
+	err    error
+
 	// a clone of slices to give out to clients, indexed by the
 	// the original slice's first byte address.  we clone them
 	// just so we're able to corrupt them on close.
@@ -660,6 +691,9 @@ func (rc *rowsCursor) Next(dest []driver.Value) error {
 		return errors.New("fakedb: cursor is closed")
 	}
 	rc.pos++
+	if rc.pos == rc.errPos {
+		return rc.err
+	}
 	if rc.pos >= len(rc.rows) {
 		return io.EOF // per interface spec
 	}