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Diffstat (limited to 'vendor/golang.org/x/net/webdav/internal/xml/typeinfo.go')
-rw-r--r--vendor/golang.org/x/net/webdav/internal/xml/typeinfo.go371
1 files changed, 371 insertions, 0 deletions
diff --git a/vendor/golang.org/x/net/webdav/internal/xml/typeinfo.go b/vendor/golang.org/x/net/webdav/internal/xml/typeinfo.go
new file mode 100644
index 0000000..fdde288
--- /dev/null
+++ b/vendor/golang.org/x/net/webdav/internal/xml/typeinfo.go
@@ -0,0 +1,371 @@
+// Copyright 2011 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 xml
+
+import (
+ "fmt"
+ "reflect"
+ "strings"
+ "sync"
+)
+
+// typeInfo holds details for the xml representation of a type.
+type typeInfo struct {
+ xmlname *fieldInfo
+ fields []fieldInfo
+}
+
+// fieldInfo holds details for the xml representation of a single field.
+type fieldInfo struct {
+ idx []int
+ name string
+ xmlns string
+ flags fieldFlags
+ parents []string
+}
+
+type fieldFlags int
+
+const (
+ fElement fieldFlags = 1 << iota
+ fAttr
+ fCharData
+ fInnerXml
+ fComment
+ fAny
+
+ fOmitEmpty
+
+ fMode = fElement | fAttr | fCharData | fInnerXml | fComment | fAny
+)
+
+var tinfoMap = make(map[reflect.Type]*typeInfo)
+var tinfoLock sync.RWMutex
+
+var nameType = reflect.TypeOf(Name{})
+
+// getTypeInfo returns the typeInfo structure with details necessary
+// for marshalling and unmarshalling typ.
+func getTypeInfo(typ reflect.Type) (*typeInfo, error) {
+ tinfoLock.RLock()
+ tinfo, ok := tinfoMap[typ]
+ tinfoLock.RUnlock()
+ if ok {
+ return tinfo, nil
+ }
+ tinfo = &typeInfo{}
+ if typ.Kind() == reflect.Struct && typ != nameType {
+ n := typ.NumField()
+ for i := 0; i < n; i++ {
+ f := typ.Field(i)
+ if f.PkgPath != "" || f.Tag.Get("xml") == "-" {
+ continue // Private field
+ }
+
+ // For embedded structs, embed its fields.
+ if f.Anonymous {
+ t := f.Type
+ if t.Kind() == reflect.Ptr {
+ t = t.Elem()
+ }
+ if t.Kind() == reflect.Struct {
+ inner, err := getTypeInfo(t)
+ if err != nil {
+ return nil, err
+ }
+ if tinfo.xmlname == nil {
+ tinfo.xmlname = inner.xmlname
+ }
+ for _, finfo := range inner.fields {
+ finfo.idx = append([]int{i}, finfo.idx...)
+ if err := addFieldInfo(typ, tinfo, &finfo); err != nil {
+ return nil, err
+ }
+ }
+ continue
+ }
+ }
+
+ finfo, err := structFieldInfo(typ, &f)
+ if err != nil {
+ return nil, err
+ }
+
+ if f.Name == "XMLName" {
+ tinfo.xmlname = finfo
+ continue
+ }
+
+ // Add the field if it doesn't conflict with other fields.
+ if err := addFieldInfo(typ, tinfo, finfo); err != nil {
+ return nil, err
+ }
+ }
+ }
+ tinfoLock.Lock()
+ tinfoMap[typ] = tinfo
+ tinfoLock.Unlock()
+ return tinfo, nil
+}
+
+// structFieldInfo builds and returns a fieldInfo for f.
+func structFieldInfo(typ reflect.Type, f *reflect.StructField) (*fieldInfo, error) {
+ finfo := &fieldInfo{idx: f.Index}
+
+ // Split the tag from the xml namespace if necessary.
+ tag := f.Tag.Get("xml")
+ if i := strings.Index(tag, " "); i >= 0 {
+ finfo.xmlns, tag = tag[:i], tag[i+1:]
+ }
+
+ // Parse flags.
+ tokens := strings.Split(tag, ",")
+ if len(tokens) == 1 {
+ finfo.flags = fElement
+ } else {
+ tag = tokens[0]
+ for _, flag := range tokens[1:] {
+ switch flag {
+ case "attr":
+ finfo.flags |= fAttr
+ case "chardata":
+ finfo.flags |= fCharData
+ case "innerxml":
+ finfo.flags |= fInnerXml
+ case "comment":
+ finfo.flags |= fComment
+ case "any":
+ finfo.flags |= fAny
+ case "omitempty":
+ finfo.flags |= fOmitEmpty
+ }
+ }
+
+ // Validate the flags used.
+ valid := true
+ switch mode := finfo.flags & fMode; mode {
+ case 0:
+ finfo.flags |= fElement
+ case fAttr, fCharData, fInnerXml, fComment, fAny:
+ if f.Name == "XMLName" || tag != "" && mode != fAttr {
+ valid = false
+ }
+ default:
+ // This will also catch multiple modes in a single field.
+ valid = false
+ }
+ if finfo.flags&fMode == fAny {
+ finfo.flags |= fElement
+ }
+ if finfo.flags&fOmitEmpty != 0 && finfo.flags&(fElement|fAttr) == 0 {
+ valid = false
+ }
+ if !valid {
+ return nil, fmt.Errorf("xml: invalid tag in field %s of type %s: %q",
+ f.Name, typ, f.Tag.Get("xml"))
+ }
+ }
+
+ // Use of xmlns without a name is not allowed.
+ if finfo.xmlns != "" && tag == "" {
+ return nil, fmt.Errorf("xml: namespace without name in field %s of type %s: %q",
+ f.Name, typ, f.Tag.Get("xml"))
+ }
+
+ if f.Name == "XMLName" {
+ // The XMLName field records the XML element name. Don't
+ // process it as usual because its name should default to
+ // empty rather than to the field name.
+ finfo.name = tag
+ return finfo, nil
+ }
+
+ if tag == "" {
+ // If the name part of the tag is completely empty, get
+ // default from XMLName of underlying struct if feasible,
+ // or field name otherwise.
+ if xmlname := lookupXMLName(f.Type); xmlname != nil {
+ finfo.xmlns, finfo.name = xmlname.xmlns, xmlname.name
+ } else {
+ finfo.name = f.Name
+ }
+ return finfo, nil
+ }
+
+ if finfo.xmlns == "" && finfo.flags&fAttr == 0 {
+ // If it's an element no namespace specified, get the default
+ // from the XMLName of enclosing struct if possible.
+ if xmlname := lookupXMLName(typ); xmlname != nil {
+ finfo.xmlns = xmlname.xmlns
+ }
+ }
+
+ // Prepare field name and parents.
+ parents := strings.Split(tag, ">")
+ if parents[0] == "" {
+ parents[0] = f.Name
+ }
+ if parents[len(parents)-1] == "" {
+ return nil, fmt.Errorf("xml: trailing '>' in field %s of type %s", f.Name, typ)
+ }
+ finfo.name = parents[len(parents)-1]
+ if len(parents) > 1 {
+ if (finfo.flags & fElement) == 0 {
+ return nil, fmt.Errorf("xml: %s chain not valid with %s flag", tag, strings.Join(tokens[1:], ","))
+ }
+ finfo.parents = parents[:len(parents)-1]
+ }
+
+ // If the field type has an XMLName field, the names must match
+ // so that the behavior of both marshalling and unmarshalling
+ // is straightforward and unambiguous.
+ if finfo.flags&fElement != 0 {
+ ftyp := f.Type
+ xmlname := lookupXMLName(ftyp)
+ if xmlname != nil && xmlname.name != finfo.name {
+ return nil, fmt.Errorf("xml: name %q in tag of %s.%s conflicts with name %q in %s.XMLName",
+ finfo.name, typ, f.Name, xmlname.name, ftyp)
+ }
+ }
+ return finfo, nil
+}
+
+// lookupXMLName returns the fieldInfo for typ's XMLName field
+// in case it exists and has a valid xml field tag, otherwise
+// it returns nil.
+func lookupXMLName(typ reflect.Type) (xmlname *fieldInfo) {
+ for typ.Kind() == reflect.Ptr {
+ typ = typ.Elem()
+ }
+ if typ.Kind() != reflect.Struct {
+ return nil
+ }
+ for i, n := 0, typ.NumField(); i < n; i++ {
+ f := typ.Field(i)
+ if f.Name != "XMLName" {
+ continue
+ }
+ finfo, err := structFieldInfo(typ, &f)
+ if finfo.name != "" && err == nil {
+ return finfo
+ }
+ // Also consider errors as a non-existent field tag
+ // and let getTypeInfo itself report the error.
+ break
+ }
+ return nil
+}
+
+func min(a, b int) int {
+ if a <= b {
+ return a
+ }
+ return b
+}
+
+// addFieldInfo adds finfo to tinfo.fields if there are no
+// conflicts, or if conflicts arise from previous fields that were
+// obtained from deeper embedded structures than finfo. In the latter
+// case, the conflicting entries are dropped.
+// A conflict occurs when the path (parent + name) to a field is
+// itself a prefix of another path, or when two paths match exactly.
+// It is okay for field paths to share a common, shorter prefix.
+func addFieldInfo(typ reflect.Type, tinfo *typeInfo, newf *fieldInfo) error {
+ var conflicts []int
+Loop:
+ // First, figure all conflicts. Most working code will have none.
+ for i := range tinfo.fields {
+ oldf := &tinfo.fields[i]
+ if oldf.flags&fMode != newf.flags&fMode {
+ continue
+ }
+ if oldf.xmlns != "" && newf.xmlns != "" && oldf.xmlns != newf.xmlns {
+ continue
+ }
+ minl := min(len(newf.parents), len(oldf.parents))
+ for p := 0; p < minl; p++ {
+ if oldf.parents[p] != newf.parents[p] {
+ continue Loop
+ }
+ }
+ if len(oldf.parents) > len(newf.parents) {
+ if oldf.parents[len(newf.parents)] == newf.name {
+ conflicts = append(conflicts, i)
+ }
+ } else if len(oldf.parents) < len(newf.parents) {
+ if newf.parents[len(oldf.parents)] == oldf.name {
+ conflicts = append(conflicts, i)
+ }
+ } else {
+ if newf.name == oldf.name {
+ conflicts = append(conflicts, i)
+ }
+ }
+ }
+ // Without conflicts, add the new field and return.
+ if conflicts == nil {
+ tinfo.fields = append(tinfo.fields, *newf)
+ return nil
+ }
+
+ // If any conflict is shallower, ignore the new field.
+ // This matches the Go field resolution on embedding.
+ for _, i := range conflicts {
+ if len(tinfo.fields[i].idx) < len(newf.idx) {
+ return nil
+ }
+ }
+
+ // Otherwise, if any of them is at the same depth level, it's an error.
+ for _, i := range conflicts {
+ oldf := &tinfo.fields[i]
+ if len(oldf.idx) == len(newf.idx) {
+ f1 := typ.FieldByIndex(oldf.idx)
+ f2 := typ.FieldByIndex(newf.idx)
+ return &TagPathError{typ, f1.Name, f1.Tag.Get("xml"), f2.Name, f2.Tag.Get("xml")}
+ }
+ }
+
+ // Otherwise, the new field is shallower, and thus takes precedence,
+ // so drop the conflicting fields from tinfo and append the new one.
+ for c := len(conflicts) - 1; c >= 0; c-- {
+ i := conflicts[c]
+ copy(tinfo.fields[i:], tinfo.fields[i+1:])
+ tinfo.fields = tinfo.fields[:len(tinfo.fields)-1]
+ }
+ tinfo.fields = append(tinfo.fields, *newf)
+ return nil
+}
+
+// A TagPathError represents an error in the unmarshalling process
+// caused by the use of field tags with conflicting paths.
+type TagPathError struct {
+ Struct reflect.Type
+ Field1, Tag1 string
+ Field2, Tag2 string
+}
+
+func (e *TagPathError) Error() string {
+ return fmt.Sprintf("%s field %q with tag %q conflicts with field %q with tag %q", e.Struct, e.Field1, e.Tag1, e.Field2, e.Tag2)
+}
+
+// value returns v's field value corresponding to finfo.
+// It's equivalent to v.FieldByIndex(finfo.idx), but initializes
+// and dereferences pointers as necessary.
+func (finfo *fieldInfo) value(v reflect.Value) reflect.Value {
+ for i, x := range finfo.idx {
+ if i > 0 {
+ t := v.Type()
+ if t.Kind() == reflect.Ptr && t.Elem().Kind() == reflect.Struct {
+ if v.IsNil() {
+ v.Set(reflect.New(v.Type().Elem()))
+ }
+ v = v.Elem()
+ }
+ }
+ v = v.Field(x)
+ }
+ return v
+}