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author | Péter Szilágyi <peterke@gmail.com> | 2016-02-11 22:16:52 +0800 |
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committer | Péter Szilágyi <peterke@gmail.com> | 2016-02-11 22:16:52 +0800 |
commit | b019f3ee29ce55c3d515ee8bafe0f4bb14221c0a (patch) | |
tree | 26e023be6c99a10e82a5a0ebadd1e42cefe9bd3c /Godeps/_workspace/src/github.com/davecgh/go-spew/spew/common.go | |
parent | b05e472c076d30035233d6a8b5fb3360b236e3ff (diff) | |
download | go-tangerine-b019f3ee29ce55c3d515ee8bafe0f4bb14221c0a.tar.gz go-tangerine-b019f3ee29ce55c3d515ee8bafe0f4bb14221c0a.tar.zst go-tangerine-b019f3ee29ce55c3d515ee8bafe0f4bb14221c0a.zip |
Godeps: update all dependencies to latest code
Diffstat (limited to 'Godeps/_workspace/src/github.com/davecgh/go-spew/spew/common.go')
-rw-r--r-- | Godeps/_workspace/src/github.com/davecgh/go-spew/spew/common.go | 135 |
1 files changed, 13 insertions, 122 deletions
diff --git a/Godeps/_workspace/src/github.com/davecgh/go-spew/spew/common.go b/Godeps/_workspace/src/github.com/davecgh/go-spew/spew/common.go index 8252cd3ee..14f02dc15 100644 --- a/Godeps/_workspace/src/github.com/davecgh/go-spew/spew/common.go +++ b/Godeps/_workspace/src/github.com/davecgh/go-spew/spew/common.go @@ -23,116 +23,8 @@ import ( "reflect" "sort" "strconv" - "unsafe" ) -const ( - // ptrSize is the size of a pointer on the current arch. - ptrSize = unsafe.Sizeof((*byte)(nil)) -) - -var ( - // offsetPtr, offsetScalar, and offsetFlag are the offsets for the - // internal reflect.Value fields. These values are valid before golang - // commit ecccf07e7f9d which changed the format. The are also valid - // after commit 82f48826c6c7 which changed the format again to mirror - // the original format. Code in the init function updates these offsets - // as necessary. - offsetPtr = uintptr(ptrSize) - offsetScalar = uintptr(0) - offsetFlag = uintptr(ptrSize * 2) - - // flagKindWidth and flagKindShift indicate various bits that the - // reflect package uses internally to track kind information. - // - // flagRO indicates whether or not the value field of a reflect.Value is - // read-only. - // - // flagIndir indicates whether the value field of a reflect.Value is - // the actual data or a pointer to the data. - // - // These values are valid before golang commit 90a7c3c86944 which - // changed their positions. Code in the init function updates these - // flags as necessary. - flagKindWidth = uintptr(5) - flagKindShift = uintptr(flagKindWidth - 1) - flagRO = uintptr(1 << 0) - flagIndir = uintptr(1 << 1) -) - -func init() { - // Older versions of reflect.Value stored small integers directly in the - // ptr field (which is named val in the older versions). Versions - // between commits ecccf07e7f9d and 82f48826c6c7 added a new field named - // scalar for this purpose which unfortunately came before the flag - // field, so the offset of the flag field is different for those - // versions. - // - // This code constructs a new reflect.Value from a known small integer - // and checks if the size of the reflect.Value struct indicates it has - // the scalar field. When it does, the offsets are updated accordingly. - vv := reflect.ValueOf(0xf00) - if unsafe.Sizeof(vv) == (ptrSize * 4) { - offsetScalar = ptrSize * 2 - offsetFlag = ptrSize * 3 - } - - // Commit 90a7c3c86944 changed the flag positions such that the low - // order bits are the kind. This code extracts the kind from the flags - // field and ensures it's the correct type. When it's not, the flag - // order has been changed to the newer format, so the flags are updated - // accordingly. - upf := unsafe.Pointer(uintptr(unsafe.Pointer(&vv)) + offsetFlag) - upfv := *(*uintptr)(upf) - flagKindMask := uintptr((1<<flagKindWidth - 1) << flagKindShift) - if (upfv&flagKindMask)>>flagKindShift != uintptr(reflect.Int) { - flagKindShift = 0 - flagRO = 1 << 5 - flagIndir = 1 << 6 - } -} - -// 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) (rv reflect.Value) { - indirects := 1 - vt := v.Type() - upv := unsafe.Pointer(uintptr(unsafe.Pointer(&v)) + offsetPtr) - rvf := *(*uintptr)(unsafe.Pointer(uintptr(unsafe.Pointer(&v)) + offsetFlag)) - if rvf&flagIndir != 0 { - vt = reflect.PtrTo(v.Type()) - indirects++ - } else if offsetScalar != 0 { - // The value is in the scalar field when it's not one of the - // reference types. - switch vt.Kind() { - case reflect.Uintptr: - case reflect.Chan: - case reflect.Func: - case reflect.Map: - case reflect.Ptr: - case reflect.UnsafePointer: - default: - upv = unsafe.Pointer(uintptr(unsafe.Pointer(&v)) + - offsetScalar) - } - } - - pv := reflect.NewAt(vt, upv) - rv = pv - for i := 0; i < indirects; i++ { - rv = rv.Elem() - } - return rv -} - // Some constants in the form of bytes to avoid string overhead. This mirrors // the technique used in the fmt package. var ( @@ -194,9 +86,14 @@ func handleMethods(cs *ConfigState, w io.Writer, v reflect.Value) (handled bool) // We need an interface to check if the type implements the error or // Stringer interface. However, the reflect package won't give us an // interface on certain things like unexported struct fields in order - // to enforce visibility rules. We use unsafe to bypass these restrictions - // since this package does not mutate the values. + // to enforce visibility rules. We use unsafe, when it's available, + // to bypass these restrictions since this package does not mutate the + // values. if !v.CanInterface() { + if UnsafeDisabled { + return false + } + v = unsafeReflectValue(v) } @@ -206,21 +103,15 @@ func handleMethods(cs *ConfigState, w io.Writer, v reflect.Value) (handled bool) // mutate the value, however, types which choose to satisify an error or // Stringer interface with a pointer receiver should not be mutating their // state inside these interface methods. - var viface interface{} - if !cs.DisablePointerMethods { - if !v.CanAddr() { - v = unsafeReflectValue(v) - } - viface = v.Addr().Interface() - } else { - if v.CanAddr() { - v = v.Addr() - } - viface = v.Interface() + if !cs.DisablePointerMethods && !UnsafeDisabled && !v.CanAddr() { + v = unsafeReflectValue(v) + } + if v.CanAddr() { + v = v.Addr() } // Is it an error or Stringer? - switch iface := viface.(type) { + switch iface := v.Interface().(type) { case error: defer catchPanic(w, v) if cs.ContinueOnMethod { |