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-rw-r--r--vendor/github.com/ghodss/yaml/fields.go501
1 files changed, 501 insertions, 0 deletions
diff --git a/vendor/github.com/ghodss/yaml/fields.go b/vendor/github.com/ghodss/yaml/fields.go
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+// Copyright 2013 The Go Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style
+// license that can be found in the LICENSE file.
+package yaml
+
+import (
+ "bytes"
+ "encoding"
+ "encoding/json"
+ "reflect"
+ "sort"
+ "strings"
+ "sync"
+ "unicode"
+ "unicode/utf8"
+)
+
+// indirect walks down v allocating pointers as needed,
+// until it gets to a non-pointer.
+// if it encounters an Unmarshaler, indirect stops and returns that.
+// if decodingNull is true, indirect stops at the last pointer so it can be set to nil.
+func indirect(v reflect.Value, decodingNull bool) (json.Unmarshaler, encoding.TextUnmarshaler, reflect.Value) {
+ // If v is a named type and is addressable,
+ // start with its address, so that if the type has pointer methods,
+ // we find them.
+ if v.Kind() != reflect.Ptr && v.Type().Name() != "" && v.CanAddr() {
+ v = v.Addr()
+ }
+ for {
+ // Load value from interface, but only if the result will be
+ // usefully addressable.
+ if v.Kind() == reflect.Interface && !v.IsNil() {
+ e := v.Elem()
+ if e.Kind() == reflect.Ptr && !e.IsNil() && (!decodingNull || e.Elem().Kind() == reflect.Ptr) {
+ v = e
+ continue
+ }
+ }
+
+ if v.Kind() != reflect.Ptr {
+ break
+ }
+
+ if v.Elem().Kind() != reflect.Ptr && decodingNull && v.CanSet() {
+ break
+ }
+ if v.IsNil() {
+ if v.CanSet() {
+ v.Set(reflect.New(v.Type().Elem()))
+ } else {
+ v = reflect.New(v.Type().Elem())
+ }
+ }
+ if v.Type().NumMethod() > 0 {
+ if u, ok := v.Interface().(json.Unmarshaler); ok {
+ return u, nil, reflect.Value{}
+ }
+ if u, ok := v.Interface().(encoding.TextUnmarshaler); ok {
+ return nil, u, reflect.Value{}
+ }
+ }
+ v = v.Elem()
+ }
+ return nil, nil, v
+}
+
+// A field represents a single field found in a struct.
+type field struct {
+ name string
+ nameBytes []byte // []byte(name)
+ equalFold func(s, t []byte) bool // bytes.EqualFold or equivalent
+
+ tag bool
+ index []int
+ typ reflect.Type
+ omitEmpty bool
+ quoted bool
+}
+
+func fillField(f field) field {
+ f.nameBytes = []byte(f.name)
+ f.equalFold = foldFunc(f.nameBytes)
+ return f
+}
+
+// byName sorts field by name, breaking ties with depth,
+// then breaking ties with "name came from json tag", then
+// breaking ties with index sequence.
+type byName []field
+
+func (x byName) Len() int { return len(x) }
+
+func (x byName) Swap(i, j int) { x[i], x[j] = x[j], x[i] }
+
+func (x byName) Less(i, j int) bool {
+ if x[i].name != x[j].name {
+ return x[i].name < x[j].name
+ }
+ if len(x[i].index) != len(x[j].index) {
+ return len(x[i].index) < len(x[j].index)
+ }
+ if x[i].tag != x[j].tag {
+ return x[i].tag
+ }
+ return byIndex(x).Less(i, j)
+}
+
+// byIndex sorts field by index sequence.
+type byIndex []field
+
+func (x byIndex) Len() int { return len(x) }
+
+func (x byIndex) Swap(i, j int) { x[i], x[j] = x[j], x[i] }
+
+func (x byIndex) Less(i, j int) bool {
+ for k, xik := range x[i].index {
+ if k >= len(x[j].index) {
+ return false
+ }
+ if xik != x[j].index[k] {
+ return xik < x[j].index[k]
+ }
+ }
+ return len(x[i].index) < len(x[j].index)
+}
+
+// typeFields returns a list of fields that JSON should recognize for the given type.
+// The algorithm is breadth-first search over the set of structs to include - the top struct
+// and then any reachable anonymous structs.
+func typeFields(t reflect.Type) []field {
+ // Anonymous fields to explore at the current level and the next.
+ current := []field{}
+ next := []field{{typ: t}}
+
+ // Count of queued names for current level and the next.
+ count := map[reflect.Type]int{}
+ nextCount := map[reflect.Type]int{}
+
+ // Types already visited at an earlier level.
+ visited := map[reflect.Type]bool{}
+
+ // Fields found.
+ var fields []field
+
+ for len(next) > 0 {
+ current, next = next, current[:0]
+ count, nextCount = nextCount, map[reflect.Type]int{}
+
+ for _, f := range current {
+ if visited[f.typ] {
+ continue
+ }
+ visited[f.typ] = true
+
+ // Scan f.typ for fields to include.
+ for i := 0; i < f.typ.NumField(); i++ {
+ sf := f.typ.Field(i)
+ if sf.PkgPath != "" { // unexported
+ continue
+ }
+ tag := sf.Tag.Get("json")
+ if tag == "-" {
+ continue
+ }
+ name, opts := parseTag(tag)
+ if !isValidTag(name) {
+ name = ""
+ }
+ index := make([]int, len(f.index)+1)
+ copy(index, f.index)
+ index[len(f.index)] = i
+
+ ft := sf.Type
+ if ft.Name() == "" && ft.Kind() == reflect.Ptr {
+ // Follow pointer.
+ ft = ft.Elem()
+ }
+
+ // Record found field and index sequence.
+ if name != "" || !sf.Anonymous || ft.Kind() != reflect.Struct {
+ tagged := name != ""
+ if name == "" {
+ name = sf.Name
+ }
+ fields = append(fields, fillField(field{
+ name: name,
+ tag: tagged,
+ index: index,
+ typ: ft,
+ omitEmpty: opts.Contains("omitempty"),
+ quoted: opts.Contains("string"),
+ }))
+ if count[f.typ] > 1 {
+ // If there were multiple instances, add a second,
+ // so that the annihilation code will see a duplicate.
+ // It only cares about the distinction between 1 or 2,
+ // so don't bother generating any more copies.
+ fields = append(fields, fields[len(fields)-1])
+ }
+ continue
+ }
+
+ // Record new anonymous struct to explore in next round.
+ nextCount[ft]++
+ if nextCount[ft] == 1 {
+ next = append(next, fillField(field{name: ft.Name(), index: index, typ: ft}))
+ }
+ }
+ }
+ }
+
+ sort.Sort(byName(fields))
+
+ // Delete all fields that are hidden by the Go rules for embedded fields,
+ // except that fields with JSON tags are promoted.
+
+ // The fields are sorted in primary order of name, secondary order
+ // of field index length. Loop over names; for each name, delete
+ // hidden fields by choosing the one dominant field that survives.
+ out := fields[:0]
+ for advance, i := 0, 0; i < len(fields); i += advance {
+ // One iteration per name.
+ // Find the sequence of fields with the name of this first field.
+ fi := fields[i]
+ name := fi.name
+ for advance = 1; i+advance < len(fields); advance++ {
+ fj := fields[i+advance]
+ if fj.name != name {
+ break
+ }
+ }
+ if advance == 1 { // Only one field with this name
+ out = append(out, fi)
+ continue
+ }
+ dominant, ok := dominantField(fields[i : i+advance])
+ if ok {
+ out = append(out, dominant)
+ }
+ }
+
+ fields = out
+ sort.Sort(byIndex(fields))
+
+ return fields
+}
+
+// dominantField looks through the fields, all of which are known to
+// have the same name, to find the single field that dominates the
+// others using Go's embedding rules, modified by the presence of
+// JSON tags. If there are multiple top-level fields, the boolean
+// will be false: This condition is an error in Go and we skip all
+// the fields.
+func dominantField(fields []field) (field, bool) {
+ // The fields are sorted in increasing index-length order. The winner
+ // must therefore be one with the shortest index length. Drop all
+ // longer entries, which is easy: just truncate the slice.
+ length := len(fields[0].index)
+ tagged := -1 // Index of first tagged field.
+ for i, f := range fields {
+ if len(f.index) > length {
+ fields = fields[:i]
+ break
+ }
+ if f.tag {
+ if tagged >= 0 {
+ // Multiple tagged fields at the same level: conflict.
+ // Return no field.
+ return field{}, false
+ }
+ tagged = i
+ }
+ }
+ if tagged >= 0 {
+ return fields[tagged], true
+ }
+ // All remaining fields have the same length. If there's more than one,
+ // we have a conflict (two fields named "X" at the same level) and we
+ // return no field.
+ if len(fields) > 1 {
+ return field{}, false
+ }
+ return fields[0], true
+}
+
+var fieldCache struct {
+ sync.RWMutex
+ m map[reflect.Type][]field
+}
+
+// cachedTypeFields is like typeFields but uses a cache to avoid repeated work.
+func cachedTypeFields(t reflect.Type) []field {
+ fieldCache.RLock()
+ f := fieldCache.m[t]
+ fieldCache.RUnlock()
+ if f != nil {
+ return f
+ }
+
+ // Compute fields without lock.
+ // Might duplicate effort but won't hold other computations back.
+ f = typeFields(t)
+ if f == nil {
+ f = []field{}
+ }
+
+ fieldCache.Lock()
+ if fieldCache.m == nil {
+ fieldCache.m = map[reflect.Type][]field{}
+ }
+ fieldCache.m[t] = f
+ fieldCache.Unlock()
+ return f
+}
+
+func isValidTag(s string) bool {
+ if s == "" {
+ return false
+ }
+ for _, c := range s {
+ switch {
+ case strings.ContainsRune("!#$%&()*+-./:<=>?@[]^_{|}~ ", c):
+ // Backslash and quote chars are reserved, but
+ // otherwise any punctuation chars are allowed
+ // in a tag name.
+ default:
+ if !unicode.IsLetter(c) && !unicode.IsDigit(c) {
+ return false
+ }
+ }
+ }
+ return true
+}
+
+const (
+ caseMask = ^byte(0x20) // Mask to ignore case in ASCII.
+ kelvin = '\u212a'
+ smallLongEss = '\u017f'
+)
+
+// foldFunc returns one of four different case folding equivalence
+// functions, from most general (and slow) to fastest:
+//
+// 1) bytes.EqualFold, if the key s contains any non-ASCII UTF-8
+// 2) equalFoldRight, if s contains special folding ASCII ('k', 'K', 's', 'S')
+// 3) asciiEqualFold, no special, but includes non-letters (including _)
+// 4) simpleLetterEqualFold, no specials, no non-letters.
+//
+// The letters S and K are special because they map to 3 runes, not just 2:
+// * S maps to s and to U+017F 'ſ' Latin small letter long s
+// * k maps to K and to U+212A 'K' Kelvin sign
+// See http://play.golang.org/p/tTxjOc0OGo
+//
+// The returned function is specialized for matching against s and
+// should only be given s. It's not curried for performance reasons.
+func foldFunc(s []byte) func(s, t []byte) bool {
+ nonLetter := false
+ special := false // special letter
+ for _, b := range s {
+ if b >= utf8.RuneSelf {
+ return bytes.EqualFold
+ }
+ upper := b & caseMask
+ if upper < 'A' || upper > 'Z' {
+ nonLetter = true
+ } else if upper == 'K' || upper == 'S' {
+ // See above for why these letters are special.
+ special = true
+ }
+ }
+ if special {
+ return equalFoldRight
+ }
+ if nonLetter {
+ return asciiEqualFold
+ }
+ return simpleLetterEqualFold
+}
+
+// equalFoldRight is a specialization of bytes.EqualFold when s is
+// known to be all ASCII (including punctuation), but contains an 's',
+// 'S', 'k', or 'K', requiring a Unicode fold on the bytes in t.
+// See comments on foldFunc.
+func equalFoldRight(s, t []byte) bool {
+ for _, sb := range s {
+ if len(t) == 0 {
+ return false
+ }
+ tb := t[0]
+ if tb < utf8.RuneSelf {
+ if sb != tb {
+ sbUpper := sb & caseMask
+ if 'A' <= sbUpper && sbUpper <= 'Z' {
+ if sbUpper != tb&caseMask {
+ return false
+ }
+ } else {
+ return false
+ }
+ }
+ t = t[1:]
+ continue
+ }
+ // sb is ASCII and t is not. t must be either kelvin
+ // sign or long s; sb must be s, S, k, or K.
+ tr, size := utf8.DecodeRune(t)
+ switch sb {
+ case 's', 'S':
+ if tr != smallLongEss {
+ return false
+ }
+ case 'k', 'K':
+ if tr != kelvin {
+ return false
+ }
+ default:
+ return false
+ }
+ t = t[size:]
+
+ }
+ if len(t) > 0 {
+ return false
+ }
+ return true
+}
+
+// asciiEqualFold is a specialization of bytes.EqualFold for use when
+// s is all ASCII (but may contain non-letters) and contains no
+// special-folding letters.
+// See comments on foldFunc.
+func asciiEqualFold(s, t []byte) bool {
+ if len(s) != len(t) {
+ return false
+ }
+ for i, sb := range s {
+ tb := t[i]
+ if sb == tb {
+ continue
+ }
+ if ('a' <= sb && sb <= 'z') || ('A' <= sb && sb <= 'Z') {
+ if sb&caseMask != tb&caseMask {
+ return false
+ }
+ } else {
+ return false
+ }
+ }
+ return true
+}
+
+// simpleLetterEqualFold is a specialization of bytes.EqualFold for
+// use when s is all ASCII letters (no underscores, etc) and also
+// doesn't contain 'k', 'K', 's', or 'S'.
+// See comments on foldFunc.
+func simpleLetterEqualFold(s, t []byte) bool {
+ if len(s) != len(t) {
+ return false
+ }
+ for i, b := range s {
+ if b&caseMask != t[i]&caseMask {
+ return false
+ }
+ }
+ return true
+}
+
+// tagOptions is the string following a comma in a struct field's "json"
+// tag, or the empty string. It does not include the leading comma.
+type tagOptions string
+
+// parseTag splits a struct field's json tag into its name and
+// comma-separated options.
+func parseTag(tag string) (string, tagOptions) {
+ if idx := strings.Index(tag, ","); idx != -1 {
+ return tag[:idx], tagOptions(tag[idx+1:])
+ }
+ return tag, tagOptions("")
+}
+
+// Contains reports whether a comma-separated list of options
+// contains a particular substr flag. substr must be surrounded by a
+// string boundary or commas.
+func (o tagOptions) Contains(optionName string) bool {
+ if len(o) == 0 {
+ return false
+ }
+ s := string(o)
+ for s != "" {
+ var next string
+ i := strings.Index(s, ",")
+ if i >= 0 {
+ s, next = s[:i], s[i+1:]
+ }
+ if s == optionName {
+ return true
+ }
+ s = next
+ }
+ return false
+}
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