From 892cd0b63638ec856e6fef1bdaaa20a177695fea Mon Sep 17 00:00:00 2001 From: cuiweixie Date: Mon, 25 Apr 2022 05:21:35 +0000 Subject: reflect: support Len and Cap on pointer-to-array Value Fixes #52411 Change-Id: I2fd13a453622992c52d49aade7cd058cfc8a77ca GitHub-Last-Rev: d5987c2ec817ebd01d9e1adb3bd2e75274dbbabd GitHub-Pull-Request: golang/go#52423 Reviewed-on: https://go-review.googlesource.com/c/go/+/400954 Reviewed-by: Keith Randall Run-TryBot: Ian Lance Taylor TryBot-Result: Gopher Robot Reviewed-by: Keith Randall Auto-Submit: Keith Randall Reviewed-by: Ian Lance Taylor Run-TryBot: Ian Lance Taylor Auto-Submit: Ian Lance Taylor --- src/reflect/value.go | 14 ++++++++++++-- 1 file changed, 12 insertions(+), 2 deletions(-) (limited to 'src/reflect/value.go') diff --git a/src/reflect/value.go b/src/reflect/value.go index 6b5ebfae24..f92fa16fe6 100644 --- a/src/reflect/value.go +++ b/src/reflect/value.go @@ -1144,7 +1144,7 @@ func funcName(f func([]Value) []Value) string { } // Cap returns v's capacity. -// It panics if v's Kind is not Array, Chan, or Slice. +// It panics if v's Kind is not Array, Chan, Slice or pointer to Array. func (v Value) Cap() int { // capNonSlice is split out to keep Cap inlineable for slice kinds. if v.kind() == Slice { @@ -1160,6 +1160,11 @@ func (v Value) capNonSlice() int { return v.typ.Len() case Chan: return chancap(v.pointer()) + case Ptr: + if v.typ.Elem().Kind() == Array { + return v.typ.Elem().Len() + } + panic("reflect: call of reflect.Value.Cap on ptr to non-array Value") } panic(&ValueError{"reflect.Value.Cap", v.kind()}) } @@ -1600,7 +1605,7 @@ func (v Value) Kind() Kind { } // Len returns v's length. -// It panics if v's Kind is not Array, Chan, Map, Slice, or String. +// It panics if v's Kind is not Array, Chan, Map, Slice, String, or pointer to Array. func (v Value) Len() int { // lenNonSlice is split out to keep Len inlineable for slice kinds. if v.kind() == Slice { @@ -1621,6 +1626,11 @@ func (v Value) lenNonSlice() int { case String: // String is bigger than a word; assume flagIndir. return (*unsafeheader.String)(v.ptr).Len + case Ptr: + if v.typ.Elem().Kind() == Array { + return v.typ.Elem().Len() + } + panic("reflect: call of reflect.Value.Len on ptr to non-array Value") } panic(&ValueError{"reflect.Value.Len", v.kind()}) } -- cgit v1.2.3-54-g00ecf