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authorMichael Muré <batolettre@gmail.com>2018-09-30 11:10:03 +0200
committerGitHub <noreply@github.com>2018-09-30 11:10:03 +0200
commitd71bb7dd7632780cf5aad5fda84027fa03a9d0f0 (patch)
treedba6c3c0bab18f41e21cd36a9fe05d1d27a574d4 /vendor/github.com/davecgh/go-spew/spew/bypass.go
parent8fdd6bf99c111c3756056e87ffd9209875ac5c1f (diff)
parentbad9cda969b49bf1bce6799056476ac4684892df (diff)
downloadgit-bug-d71bb7dd7632780cf5aad5fda84027fa03a9d0f0.tar.gz
Merge pull request #54 from MichaelMure/editablecomment
Core support for editable comments
Diffstat (limited to 'vendor/github.com/davecgh/go-spew/spew/bypass.go')
-rw-r--r--vendor/github.com/davecgh/go-spew/spew/bypass.go145
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")
+}