diff options
Diffstat (limited to 'libgo/go/text/template/exec.go')
| -rw-r--r-- | libgo/go/text/template/exec.go | 69 |
1 files changed, 53 insertions, 16 deletions
diff --git a/libgo/go/text/template/exec.go b/libgo/go/text/template/exec.go index daba788b55b..efe1817173f 100644 --- a/libgo/go/text/template/exec.go +++ b/libgo/go/text/template/exec.go @@ -78,7 +78,23 @@ func doublePercent(str string) string { return str } -// errorf formats the error and terminates processing. +// TODO: It would be nice if ExecError was more broken down, but +// the way ErrorContext embeds the template name makes the +// processing too clumsy. + +// ExecError is the custom error type returned when Execute has an +// error evaluating its template. (If a write error occurs, the actual +// error is returned; it will not be of type ExecError.) +type ExecError struct { + Name string // Name of template. + Err error // Pre-formatted error. +} + +func (e ExecError) Error() string { + return e.Err.Error() +} + +// errorf records an ExecError and terminates processing. func (s *state) errorf(format string, args ...interface{}) { name := doublePercent(s.tmpl.Name()) if s.node == nil { @@ -87,7 +103,24 @@ func (s *state) errorf(format string, args ...interface{}) { location, context := s.tmpl.ErrorContext(s.node) format = fmt.Sprintf("template: %s: executing %q at <%s>: %s", location, name, doublePercent(context), format) } - panic(fmt.Errorf(format, args...)) + panic(ExecError{ + Name: s.tmpl.Name(), + Err: fmt.Errorf(format, args...), + }) +} + +// writeError is the wrapper type used internally when Execute has an +// error writing to its output. We strip the wrapper in errRecover. +// Note that this is not an implementation of error, so it cannot escape +// from the package as an error value. +type writeError struct { + Err error // Original error. +} + +func (s *state) writeError(err error) { + panic(writeError{ + Err: err, + }) } // errRecover is the handler that turns panics into returns from the top @@ -98,8 +131,10 @@ func errRecover(errp *error) { switch err := e.(type) { case runtime.Error: panic(e) - case error: - *errp = err + case writeError: + *errp = err.Err // Strip the wrapper. + case ExecError: + *errp = err // Keep the wrapper. default: panic(e) } @@ -145,7 +180,7 @@ func (t *Template) Execute(wr io.Writer, data interface{}) (err error) { } // DefinedTemplates returns a string listing the defined templates, -// prefixed by the string "defined templates are: ". If there are none, +// prefixed by the string "; defined templates are: ". If there are none, // it returns the empty string. For generating an error message here // and in html/template. func (t *Template) DefinedTemplates() string { @@ -193,7 +228,7 @@ func (s *state) walk(dot reflect.Value, node parse.Node) { s.walkTemplate(dot, node) case *parse.TextNode: if _, err := s.wr.Write(node.Text); err != nil { - s.errorf("%s", err) + s.writeError(err) } case *parse.WithNode: s.walkIfOrWith(parse.NodeWith, dot, node.Pipe, node.List, node.ElseList) @@ -222,8 +257,13 @@ func (s *state) walkIfOrWith(typ parse.NodeType, dot reflect.Value, pipe *parse. } } -// isTrue reports whether the value is 'true', in the sense of not the zero of its type, -// and whether the value has a meaningful truth value. +// IsTrue reports whether the value is 'true', in the sense of not the zero of its type, +// and whether the value has a meaningful truth value. This is the definition of +// truth used by if and other such actions. +func IsTrue(val interface{}) (truth, ok bool) { + return isTrue(reflect.ValueOf(val)) +} + func isTrue(val reflect.Value) (truth, ok bool) { if !val.IsValid() { // Something like var x interface{}, never set. It's a form of nil. @@ -483,7 +523,7 @@ func (s *state) evalField(dot reflect.Value, fieldName string, node parse.Node, return zero } typ := receiver.Type() - receiver, _ = indirect(receiver) + receiver, isNil := indirect(receiver) // Unless it's an interface, need to get to a value of type *T to guarantee // we see all methods of T and *T. ptr := receiver @@ -495,7 +535,6 @@ func (s *state) evalField(dot reflect.Value, fieldName string, node parse.Node, } hasArgs := len(args) > 1 || final.IsValid() // It's not a method; must be a field of a struct or an element of a map. The receiver must not be nil. - receiver, isNil := indirect(receiver) if isNil { s.errorf("nil pointer evaluating %s.%s", typ, fieldName) } @@ -789,16 +828,11 @@ func (s *state) evalEmptyInterface(dot reflect.Value, n parse.Node) reflect.Valu } // indirect returns the item at the end of indirection, and a bool to indicate if it's nil. -// We indirect through pointers and empty interfaces (only) because -// non-empty interfaces have methods we might need. func indirect(v reflect.Value) (rv reflect.Value, isNil bool) { for ; v.Kind() == reflect.Ptr || v.Kind() == reflect.Interface; v = v.Elem() { if v.IsNil() { return v, true } - if v.Kind() == reflect.Interface && v.NumMethod() > 0 { - break - } } return v, false } @@ -811,7 +845,10 @@ func (s *state) printValue(n parse.Node, v reflect.Value) { if !ok { s.errorf("can't print %s of type %s", n, v.Type()) } - fmt.Fprint(s.wr, iface) + _, err := fmt.Fprint(s.wr, iface) + if err != nil { + s.writeError(err) + } } // printableValue returns the, possibly indirected, interface value inside v that |