fmt: remove depth argument from handleMethods and printArg

handleMethods can format Error() and String() directly as its known
these return strings that can be directly printed using fmtString.
Remove the obsolete depth argument from handleMethods.

Remove the depth argument from printArg since it is only ever
called with depth set to 0. Recursion for formatting complex
arguments is handled only by printValue which keeps track of depth.

Change-Id: I4c4be588751de12ed999e7561a51bc168eb9eb2d
Reviewed-on: https://go-review.googlesource.com/20911
Run-TryBot: Rob Pike <r@golang.org>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Rob Pike <r@golang.org>

src/fmt/print.go

@@ -317,7 +317,7 @@ func (p *pp) badVerb(verb rune) {
 	case p.arg != nil:
 		p.buf.WriteString(reflect.TypeOf(p.arg).String())
 		p.buf.WriteByte('=')
-		p.printArg(p.arg, 'v', 0)
+		p.printArg(p.arg, 'v')
 	case p.value.IsValid():
 		p.buf.WriteString(p.value.Type().String())
 		p.buf.WriteByte('=')
@@ -564,13 +564,13 @@ func (p *pp) catchPanic(arg interface{}, verb rune) {
 		p.buf.WriteRune(verb)
 		p.buf.WriteString(panicString)
 		p.panicking = true
-		p.printArg(err, 'v', 0)
+		p.printArg(err, 'v')
 		p.panicking = false
 		p.buf.WriteByte(')')
 	}
 }
 
-func (p *pp) handleMethods(verb rune, depth int) (handled bool) {
+func (p *pp) handleMethods(verb rune) (handled bool) {
 	if p.erroring {
 		return
 	}
@@ -605,13 +605,13 @@ func (p *pp) handleMethods(verb rune, depth int) (handled bool) {
 			case error:
 				handled = true
 				defer p.catchPanic(p.arg, verb)
-				p.printArg(v.Error(), verb, depth)
+				p.fmtString(v.Error(), verb)
 				return
 
 			case Stringer:
 				handled = true
 				defer p.catchPanic(p.arg, verb)
-				p.printArg(v.String(), verb, depth)
+				p.fmtString(v.String(), verb)
 				return
 			}
 		}
@@ -619,7 +619,7 @@ func (p *pp) handleMethods(verb rune, depth int) (handled bool) {
 	return false
 }
 
-func (p *pp) printArg(arg interface{}, verb rune, depth int) {
+func (p *pp) printArg(arg interface{}, verb rune) {
 	p.arg = arg
 	p.value = reflect.Value{}
 
@@ -683,15 +683,15 @@ func (p *pp) printArg(arg interface{}, verb rune, depth int) {
 	case []byte:
 		p.fmtBytes(f, verb, bytesString)
 	case reflect.Value:
-		p.printReflectValue(f, verb, depth)
+		p.printReflectValue(f, verb, 0)
 		return
 	default:
 		// If the type is not simple, it might have methods.
-		if p.handleMethods(verb, depth) {
+		if p.handleMethods(verb) {
 			return
 		}
 		// Need to use reflection
-		p.printReflectValue(reflect.ValueOf(arg), verb, depth)
+		p.printReflectValue(reflect.ValueOf(arg), verb, 0)
 		return
 	}
 	p.arg = nil
@@ -716,7 +716,7 @@ func (p *pp) printValue(value reflect.Value, verb rune, depth int) {
 	if value.CanInterface() {
 		p.arg = value.Interface()
 	}
-	if p.handleMethods(verb, depth) {
+	if p.handleMethods(verb) {
 		return
 	}
 
@@ -1110,7 +1110,7 @@ func (p *pp) doPrintf(format string, a []interface{}) {
 			p.fmt.zero = false
 		}
 
-		p.printArg(a[argNum], c, 0)
+		p.printArg(a[argNum], c)
 		argNum++
 	}
 
@@ -1129,7 +1129,7 @@ func (p *pp) doPrintf(format string, a []interface{}) {
 			} else {
 				p.buf.WriteString(reflect.TypeOf(arg).String())
 				p.buf.WriteByte('=')
-				p.printArg(arg, 'v', 0)
+				p.printArg(arg, 'v')
 			}
 		}
 		p.buf.WriteByte(')')
@@ -1146,7 +1146,7 @@ func (p *pp) doPrint(a []interface{}, addspace, addnewline bool) {
 		if argNum > 0 && (addspace || (!isString && !prevString)) {
 			p.buf.WriteByte(' ')
 		}
-		p.printArg(arg, 'v', 0)
+		p.printArg(arg, 'v')
 		prevString = isString
 	}
 	if addnewline {