Avoid MISUSE in Stmt.Bind

If a Conn is interrupted then Conn.Prep will return a Stmt with
Stmt.stmt = nil. This causes SQLITE MISUSE errors to occur when any of
the Bind functions are called on the Stmt. This is confusing to users as
the error returned by Step is misleading and anyone using sqlite.Logger
will see misleading MISUSE messages. Now we check if Stmt.stmt is not
nil prior to using it in the Bind statements, which solves these issues
and makes the interrupt obvious when Stmt.Step is later called.

fix crawshaw#86

export_test.go

@@ -20,10 +20,10 @@ func ConnCount(conn *Conn) int { return conn.count }
 
 func InterruptedStmt(conn *Conn, query string) *Stmt {
  return &Stmt{
- conn: conn,
- query: query,
- bindNames: make(map[string]int),
- colNames: make(map[string]int),
- prepInterupt: true,
+ conn:  conn,
+ query:  query,
+ bindNames:  make(map[string]int),
+ colNames:  make(map[string]int),
+ prepInterrupt: true,
  }
 }

sqlite.go

@@ -358,11 +358,11 @@ func (conn *Conn) Prep(query string) *Stmt {
  if err != nil {
  if ErrCode(err) == SQLITE_INTERRUPT {
  return &Stmt{
- conn: conn,
- query: query,
- bindNames: make(map[string]int),
- colNames: make(map[string]int),
- prepInterupt: true,
+ conn:  conn,
+ query:  query,
+ bindNames:  make(map[string]int),
+ colNames:  make(map[string]int),
+ prepInterrupt: true,
  }
  }
  panic(err)
@@ -532,19 +532,20 @@ func reserr(loc, query, msg string, res C.int) error {
 // When a Stmt is no longer needed it should be cleaned up
 // by calling the Finalize method.
 type Stmt struct {
- conn *Conn
- stmt *C.sqlite3_stmt
- query string
- bindNames map[string]int
- colNames map[string]int
- bindErr error
- prepInterupt bool // set if Prep was interrupted
- lastHasRow bool // last bool returned by Step
- tracerTask TracerTask
+ conn  *Conn
+ stmt  *C.sqlite3_stmt
+ query  string
+ bindNames  map[string]int
+ colNames  map[string]int
+ bindErr  error
+ prepInterrupt bool // set if Prep was interrupted
+ lastHasRow  bool // last bool returned by Step
+ tracerTask  TracerTask
 }
 
 func (stmt *Stmt) interrupted(loc string) error {
- if stmt.prepInterupt {
+ loc = "Stmt." + loc
+ if stmt.prepInterrupt {
  return reserr(loc, stmt.query, "", C.SQLITE_INTERRUPT)
  }
  return stmt.conn.interrupted(loc, stmt.query)
@@ -599,7 +600,7 @@ func (stmt *Stmt) Reset() error {
 // https://www.sqlite.org/c3ref/clear_bindings.html
 func (stmt *Stmt) ClearBindings() error {
  stmt.conn.count++
- if err := stmt.interrupted("Stmt.ClearBindings"); err != nil {
+ if err := stmt.interrupted("ClearBindings"); err != nil {
  return err
  }
  res := C.sqlite3_clear_bindings(stmt.stmt)
@@ -668,7 +669,7 @@ func (stmt *Stmt) Step() (rowReturned bool, err error) {
 func (stmt *Stmt) step() (bool, error) {
  for {
  stmt.conn.count++
- if err := stmt.interrupted("Stmt.Step"); err != nil {
+ if err := stmt.interrupted("Step"); err != nil {
  return false, err
  }
  switch res := C.sqlite3_step(stmt.stmt); uint8(res) { // reduce to non-extended error code
@@ -699,14 +700,14 @@ func (stmt *Stmt) step() (bool, error) {
 
 func (stmt *Stmt) handleBindErr(loc string, res C.int) {
  if stmt.bindErr == nil {
- stmt.bindErr = stmt.conn.reserr(loc, stmt.query, res)
+ stmt.bindErr = stmt.conn.reserr("Stmt."+loc, stmt.query, res)
  }
 }
 
 func (stmt *Stmt) findBindName(loc string, param string) int {
  pos := stmt.bindNames[param]
  if pos == 0 && stmt.bindErr == nil {
- stmt.bindErr = reserr(loc, stmt.query, "unknown parameter: "+param, C.SQLITE_ERROR)
+ stmt.bindErr = reserr("Stmt."+loc, stmt.query, "unknown parameter: "+param, C.SQLITE_ERROR)
  }
  return pos
 }
@@ -739,6 +740,9 @@ func (stmt *Stmt) ColumnName(col int) string {
 //
 // https://www.sqlite.org/c3ref/bind_parameter_count.html
 func (stmt *Stmt) BindParamCount() int {
+ if stmt.stmt == nil {
+ return 0
+ }
  return int(C.sqlite3_bind_parameter_count(stmt.stmt))
 }
 
@@ -748,6 +752,9 @@ func (stmt *Stmt) BindParamCount() int {
 //
 // https://www.sqlite.org/c3ref/bind_blob.html
 func (stmt *Stmt) BindInt64(param int, value int64) {
+ if stmt.stmt == nil {
+ return
+ }
  res := C.sqlite3_bind_int64(stmt.stmt, C.int(param), C.sqlite3_int64(value))
  stmt.handleBindErr("BindInt64", res)
 }
@@ -758,6 +765,9 @@ func (stmt *Stmt) BindInt64(param int, value int64) {
 //
 // https://www.sqlite.org/c3ref/bind_blob.html
 func (stmt *Stmt) BindBool(param int, value bool) {
+ if stmt.stmt == nil {
+ return
+ }
  v := 0
  if value {
  v = 1
@@ -775,6 +785,9 @@ func (stmt *Stmt) BindBool(param int, value bool) {
 //
 // https://www.sqlite.org/c3ref/bind_blob.html
 func (stmt *Stmt) BindBytes(param int, value []byte) {
+ if stmt.stmt == nil {
+ return
+ }
  var v *C.char
  if len(value) != 0 {
  v = (*C.char)(unsafe.Pointer(&value[0]))
@@ -792,6 +805,9 @@ var emptyCstr = C.CString("")
 //
 // https://www.sqlite.org/c3ref/bind_blob.html
 func (stmt *Stmt) BindText(param int, value string) {
+ if stmt.stmt == nil {
+ return
+ }
  var v *C.char
  var free *[0]byte
  if len(value) == 0 {
@@ -810,6 +826,9 @@ func (stmt *Stmt) BindText(param int, value string) {
 //
 // https://www.sqlite.org/c3ref/bind_blob.html
 func (stmt *Stmt) BindFloat(param int, value float64) {
+ if stmt.stmt == nil {
+ return
+ }
  res := C.sqlite3_bind_double(stmt.stmt, C.int(param), C.double(value))
  stmt.handleBindErr("BindFloat", res)
 }
@@ -820,6 +839,9 @@ func (stmt *Stmt) BindFloat(param int, value float64) {
 //
 // https://www.sqlite.org/c3ref/bind_blob.html
 func (stmt *Stmt) BindNull(param int) {
+ if stmt.stmt == nil {
+ return
+ }
  res := C.sqlite3_bind_null(stmt.stmt, C.int(param))
  stmt.handleBindErr("BindNull", res)
 }
@@ -830,6 +852,9 @@ func (stmt *Stmt) BindNull(param int) {
 //
 // https://www.sqlite.org/c3ref/bind_blob.html
 func (stmt *Stmt) BindZeroBlob(param int, len int64) {
+ if stmt.stmt == nil {
+ return
+ }
  res := C.sqlite3_bind_zeroblob64(stmt.stmt, C.int(param), C.sqlite3_uint64(len))
  stmt.handleBindErr("BindZeroBlob", res)
 }