108 lines
2 KiB
Go
108 lines
2 KiB
Go
package namespace
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import (
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"context"
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"errors"
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"strings"
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)
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type nsContext struct {
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context.Context
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// Note: this is currently not locked because we think all uses will take
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// place within a single goroutine. If that isn't the case, this should be
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// protected by an atomic.Value.
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cachedNS *Namespace
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}
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type contextValues struct{}
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const (
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RootNamespaceID = "root"
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)
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var (
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contextNamespace contextValues = struct{}{}
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ErrNoNamespace error = errors.New("no namespace")
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)
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type Namespace struct {
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ID string `json:"id"`
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Path string `json:"path"`
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}
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func New(id, path string) *Namespace {
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return &Namespace{
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ID: id,
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Path: path,
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}
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}
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func (n *Namespace) HasParent(possibleParent *Namespace) bool {
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switch {
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case n.Path == "":
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return false
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case possibleParent.Path == "":
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return true
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default:
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return strings.HasPrefix(n.Path, possibleParent.Path)
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}
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}
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func (n *Namespace) TrimmedPath(path string) string {
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return strings.TrimPrefix(path, n.Path)
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}
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func ContextWithNamespace(ctx context.Context, ns *Namespace) context.Context {
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nsCtx := context.WithValue(ctx, contextNamespace, ns)
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return &nsContext{
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Context: nsCtx,
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cachedNS: ns,
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}
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}
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func FromContext(ctx context.Context) (*Namespace, error) {
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if ctx == nil {
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return nil, errors.New("context was nil")
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}
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nsCtx, ok := ctx.(*nsContext)
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if ok {
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if nsCtx.cachedNS != nil {
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return nsCtx.cachedNS, nil
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}
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}
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ns := ctx.Value(contextNamespace)
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if ns == nil {
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return nil, ErrNoNamespace
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}
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if ok {
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nsCtx.cachedNS = ns.(*Namespace)
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}
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return ns.(*Namespace), nil
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}
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func TestContext() context.Context {
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return ContextWithNamespace(context.Background(), New(RootNamespaceID, ""))
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}
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// Canonicalize trims any prefix '/' and adds a trailing '/' to the
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// provided string
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func Canonicalize(nsPath string) string {
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if nsPath == "" {
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return ""
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}
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// Canonicalize the path to not have a '/' prefix
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nsPath = strings.TrimPrefix(nsPath, "/")
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// Canonicalize the path to always having a '/' suffix
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if !strings.HasSuffix(nsPath, "/") {
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nsPath += "/"
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}
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return nsPath
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}
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