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author | Michael Muré <batolettre@gmail.com> | 2018-09-29 21:09:09 +0200 |
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committer | Michael Muré <batolettre@gmail.com> | 2018-09-29 21:09:09 +0200 |
commit | d450c7a883876e0f5356fb5cb54109a0a2a77dfd (patch) | |
tree | 5c04dde6492dc649f84761ba60afc3843b18ff92 /vendor/github.com/davecgh/go-spew/spew/bypass.go | |
parent | 75c921cdf9856c01ebf6ce50abfb31e403008b09 (diff) | |
download | git-bug-d450c7a883876e0f5356fb5cb54109a0a2a77dfd.tar.gz |
use more testify, fix unchecked errors
Diffstat (limited to 'vendor/github.com/davecgh/go-spew/spew/bypass.go')
-rw-r--r-- | vendor/github.com/davecgh/go-spew/spew/bypass.go | 145 |
1 files changed, 145 insertions, 0 deletions
diff --git a/vendor/github.com/davecgh/go-spew/spew/bypass.go b/vendor/github.com/davecgh/go-spew/spew/bypass.go new file mode 100644 index 00000000..79299478 --- /dev/null +++ b/vendor/github.com/davecgh/go-spew/spew/bypass.go @@ -0,0 +1,145 @@ +// Copyright (c) 2015-2016 Dave Collins <dave@davec.name> +// +// Permission to use, copy, modify, and distribute this software for any +// purpose with or without fee is hereby granted, provided that the above +// copyright notice and this permission notice appear in all copies. +// +// THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES +// WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF +// MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR +// ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES +// WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN +// ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF +// OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE. + +// NOTE: Due to the following build constraints, this file will only be compiled +// when the code is not running on Google App Engine, compiled by GopherJS, and +// "-tags safe" is not added to the go build command line. The "disableunsafe" +// tag is deprecated and thus should not be used. +// Go versions prior to 1.4 are disabled because they use a different layout +// for interfaces which make the implementation of unsafeReflectValue more complex. +// +build !js,!appengine,!safe,!disableunsafe,go1.4 + +package spew + +import ( + "reflect" + "unsafe" +) + +const ( + // UnsafeDisabled is a build-time constant which specifies whether or + // not access to the unsafe package is available. + UnsafeDisabled = false + + // ptrSize is the size of a pointer on the current arch. + ptrSize = unsafe.Sizeof((*byte)(nil)) +) + +type flag uintptr + +var ( + // flagRO indicates whether the value field of a reflect.Value + // is read-only. + flagRO flag + + // flagAddr indicates whether the address of the reflect.Value's + // value may be taken. + flagAddr flag +) + +// flagKindMask holds the bits that make up the kind +// part of the flags field. In all the supported versions, +// it is in the lower 5 bits. +const flagKindMask = flag(0x1f) + +// Different versions of Go have used different +// bit layouts for the flags type. This table +// records the known combinations. +var okFlags = []struct { + ro, addr flag +}{{ + // From Go 1.4 to 1.5 + ro: 1 << 5, + addr: 1 << 7, +}, { + // Up to Go tip. + ro: 1<<5 | 1<<6, + addr: 1 << 8, +}} + +var flagValOffset = func() uintptr { + field, ok := reflect.TypeOf(reflect.Value{}).FieldByName("flag") + if !ok { + panic("reflect.Value has no flag field") + } + return field.Offset +}() + +// flagField returns a pointer to the flag field of a reflect.Value. +func flagField(v *reflect.Value) *flag { + return (*flag)(unsafe.Pointer(uintptr(unsafe.Pointer(v)) + flagValOffset)) +} + +// unsafeReflectValue converts the passed reflect.Value into a one that bypasses +// the typical safety restrictions preventing access to unaddressable and +// unexported data. It works by digging the raw pointer to the underlying +// value out of the protected value and generating a new unprotected (unsafe) +// reflect.Value to it. +// +// This allows us to check for implementations of the Stringer and error +// interfaces to be used for pretty printing ordinarily unaddressable and +// inaccessible values such as unexported struct fields. +func unsafeReflectValue(v reflect.Value) reflect.Value { + if !v.IsValid() || (v.CanInterface() && v.CanAddr()) { + return v + } + flagFieldPtr := flagField(&v) + *flagFieldPtr &^= flagRO + *flagFieldPtr |= flagAddr + return v +} + +// Sanity checks against future reflect package changes +// to the type or semantics of the Value.flag field. +func init() { + field, ok := reflect.TypeOf(reflect.Value{}).FieldByName("flag") + if !ok { + panic("reflect.Value has no flag field") + } + if field.Type.Kind() != reflect.TypeOf(flag(0)).Kind() { + panic("reflect.Value flag field has changed kind") + } + type t0 int + var t struct { + A t0 + // t0 will have flagEmbedRO set. + t0 + // a will have flagStickyRO set + a t0 + } + vA := reflect.ValueOf(t).FieldByName("A") + va := reflect.ValueOf(t).FieldByName("a") + vt0 := reflect.ValueOf(t).FieldByName("t0") + + // Infer flagRO from the difference between the flags + // for the (otherwise identical) fields in t. + flagPublic := *flagField(&vA) + flagWithRO := *flagField(&va) | *flagField(&vt0) + flagRO = flagPublic ^ flagWithRO + + // Infer flagAddr from the difference between a value + // taken from a pointer and not. + vPtrA := reflect.ValueOf(&t).Elem().FieldByName("A") + flagNoPtr := *flagField(&vA) + flagPtr := *flagField(&vPtrA) + flagAddr = flagNoPtr ^ flagPtr + + // Check that the inferred flags tally with one of the known versions. + for _, f := range okFlags { + if flagRO == f.ro && flagAddr == f.addr { + return + } + } + panic("reflect.Value read-only flag has changed semantics") +} |