--- /dev/null
+package toml
+
+// Struct field handling is adapted from code in encoding/json:
+//
+// Copyright 2010 The Go Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style
+// license that can be found in the Go distribution.
+
+import (
+ "reflect"
+ "sort"
+ "sync"
+)
+
+// A field represents a single field found in a struct.
+type field struct {
+ name string // the name of the field (`toml` tag included)
+ tag bool // whether field has a `toml` tag
+ index []int // represents the depth of an anonymous field
+ typ reflect.Type // the type of the field
+}
+
+// byName sorts field by name, breaking ties with depth,
+// then breaking ties with "name came from toml 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 TOML 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 != "" && !sf.Anonymous { // unexported
+ continue
+ }
+ opts := getOptions(sf.Tag)
+ if opts.skip {
+ continue
+ }
+ 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 opts.name != "" || !sf.Anonymous || ft.Kind() != reflect.Struct {
+ tagged := opts.name != ""
+ name := opts.name
+ if name == "" {
+ name = sf.Name
+ }
+ fields = append(fields, field{name, tagged, index, ft})
+ 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 {
+ f := field{name: ft.Name(), index: index, typ: ft}
+ next = append(next, f)
+ }
+ }
+ }
+ }
+
+ sort.Sort(byName(fields))
+
+ // Delete all fields that are hidden by the Go rules for embedded fields,
+ // except that fields with TOML 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
+// TOML 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
+}
projects / dotfiles / .git / blobdiff