Stowage/go
2
0
Fork 0
mirror of https://github.com/golang/go.git synced 2025-12-08 06:10:04 +00:00
Code Issues Projects Releases Packages Wiki Activity

handle nils safely

Browse source 
R=rsc
DELTA=38  (14 added, 10 deleted, 14 changed)
OCL=19242
CL=19242
This commit is contained in:
Rob Pike 2008-11-14 10:42:45 -08:00
parent 22e0e1b049
commit 2355395550
1 changed files with 26 additions and 22 deletions
Download patch file Download diff file Expand all files Collapse all files

48
src/lib/fmt/print.go
View file

@ -11,16 +11,13 @@ package fmt
import (
"fmt";
"io";
"reflect";
"os";
)
export type Writer interface {
Write(b *[]byte) (ret int, err *os.Error);
}
// Representation of printer state passed to custom formatters.
// Provides access to the Writer interface plus information about
// Provides access to the io.Write interface plus information about
// the active formatting verb.
export type Formatter interface {
Write(b *[]byte) (ret int, err *os.Error);
@ -119,7 +116,7 @@ func (p *P) doprint(v reflect.StructValue, addspace, addnewline bool);
// These routines end in 'f' and take a format string.
export func fprintf(w Writer, format string, a ...) (n int, error *os.Error) {
export func fprintf(w io.Write, format string, a ...) (n int, error *os.Error) {
v := reflect.NewValue(a).(reflect.PtrValue).Sub().(reflect.StructValue);
p := Printer();
p.doprintf(format, v);
@ -143,7 +140,7 @@ export func sprintf(format string, a ...) string {
// These routines do not take a format string and add spaces only
// when the operand on neither side is a string.
export func fprint(w Writer, a ...) (n int, error *os.Error) {
export func fprint(w io.Write, a ...) (n int, error *os.Error) {
v := reflect.NewValue(a).(reflect.PtrValue).Sub().(reflect.StructValue);
p := Printer();
p.doprint(v, false, false);
@ -168,7 +165,7 @@ export func sprint(a ...) string {
// always add spaces between operands, and add a newline
// after the last operand.
export func fprintln(w Writer, a ...) (n int, error *os.Error) {
export func fprintln(w io.Write, a ...) (n int, error *os.Error) {
v := reflect.NewValue(a).(reflect.PtrValue).Sub().(reflect.StructValue);
p := Printer();
p.doprint(v, true, true);
@ -310,22 +307,25 @@ func (p *P) printField(field reflect.Value) (was_string bool) {
s = p.fmt.s(v).str();
was_string = true;
case reflect.PtrKind:
// pointer to array?
if v, ok := getArrayPtr(field); ok {
p.addstr("&[");
for i := 0; i < v.Len(); i++ {
if i > 0 {
p.addstr(" ");
if v, ok := getPtr(field); v == 0 {
s = "<nil>"
} else {
// pointer to array?
if a, ok := getArrayPtr(field); ok {
p.addstr("&[");
for i := 0; i < a.Len(); i++ {
if i > 0 {
p.addstr(" ");
}
p.printField(a.Elem(i));
}
p.printField(v.Elem(i));
p.addstr("]");
} else {
p.add('0');
p.add('x');
s = p.fmt.uX64(v).str();
}
p.addstr("]");
break;
}
v, ok := getPtr(field);
p.add('0');
p.add('x');
s = p.fmt.uX64(v).str();
case reflect.StructKind:
p.add('{');
p.doprint(field, true, false);
@ -471,7 +471,11 @@ func (p *P) doprintf(format string, v reflect.StructValue) {
// pointer
case 'p':
if v, ok := getPtr(field); ok {
s = "0x" + p.fmt.uX64(v).str()
if v == nil {
s = "<nil>"
} else {
s = "0x" + p.fmt.uX64(v).str()
}
} else {
goto badtype
}