Golang conversion.EnforcePtr函数代码示例

// SetList sets the given list object's Items member have the elements given in
// objects.
// Returns an error if list is not a List type (does not have an Items member),
// or if any of the objects are not of the right type.
func SetList(list runtime.Object, objects []runtime.Object) error {
	itemsPtr, err := GetItemsPtr(list)
	if err != nil {
		return err
	}
	items, err := conversion.EnforcePtr(itemsPtr)
	if err != nil {
		return err
	}
	if items.Type() == objectSliceType {
		items.Set(reflect.ValueOf(objects))
		return nil
	}
	slice := reflect.MakeSlice(items.Type(), len(objects), len(objects))
	for i := range objects {
		dest := slice.Index(i)
		src, err := conversion.EnforcePtr(objects[i])
		if err != nil {
			return err
		}
		if src.Type().AssignableTo(dest.Type()) {
			dest.Set(src)
		} else if src.Type().ConvertibleTo(dest.Type()) {
			dest.Set(src.Convert(dest.Type()))
		} else {
			return fmt.Errorf("item[%d]: can't assign or convert %v into %v", i, src.Type(), dest.Type())
		}
	}
	items.Set(slice)
	return nil
}

// addObjectParams converts a runtime.Object into a set of go-restful Param() definitions on the route.
// The object must be a pointer to a struct; only fields at the top level of the struct that are not
// themselves interfaces or structs are used; only fields with a json tag that is non empty (the standard
// Go JSON behavior for omitting a field) become query parameters. The name of the query parameter is
// the JSON field name. If a description struct tag is set on the field, that description is used on the
// query parameter. In essence, it converts a standard JSON top level object into a query param schema.
func addObjectParams(ws *restful.WebService, route *restful.RouteBuilder, obj interface{}) error {
	sv, err := conversion.EnforcePtr(obj)
	if err != nil {
		return err
	}
	st := sv.Type()
	switch st.Kind() {
	case reflect.Struct:
		for i := 0; i < st.NumField(); i++ {
			name := st.Field(i).Name
			sf, ok := st.FieldByName(name)
			if !ok {
				continue
			}
			switch sf.Type.Kind() {
			case reflect.Interface, reflect.Struct:
			default:
				jsonTag := sf.Tag.Get("json")
				if len(jsonTag) == 0 {
					continue
				}
				jsonName := strings.SplitN(jsonTag, ",", 2)[0]
				if len(jsonName) == 0 {
					continue
				}
				desc := sf.Tag.Get("description")
				route.Param(ws.QueryParameter(jsonName, desc).DataType(typeToJSON(sf.Type.Name())))
			}
		}
	}
	return nil
}

// ExtractList returns obj's Items element as an array of runtime.Objects.
// Returns an error if obj is not a List type (does not have an Items member).
// TODO: move me to pkg/api/meta
func ExtractList(obj Object) ([]Object, error) {
	itemsPtr, err := GetItemsPtr(obj)
	if err != nil {
		return nil, err
	}
	items, err := conversion.EnforcePtr(itemsPtr)
	if err != nil {
		return nil, err
	}
	list := make([]Object, items.Len())
	for i := range list {
		raw := items.Index(i)
		switch item := raw.Interface().(type) {
		case Object:
			list[i] = item
		case RawExtension:
			list[i] = &Unknown{
				RawJSON: item.RawJSON,
			}
		default:
			var found bool
			if list[i], found = raw.Addr().Interface().(Object); !found {
				return nil, fmt.Errorf("%v: item[%v]: Expected object, got %#v(%s)", obj, i, raw.Interface(), raw.Kind())
			}
		}
	}
	return list, nil
}

// Implements storage.Interface.
func (h *etcdHelper) Create(key string, obj, out runtime.Object, ttl uint64) error {
	key = h.prefixEtcdKey(key)
	data, err := h.codec.Encode(obj)
	if err != nil {
		return err
	}
	if h.versioner != nil {
		if version, err := h.versioner.ObjectResourceVersion(obj); err == nil && version != 0 {
			return errors.New("resourceVersion may not be set on objects to be created")
		}
	}

	startTime := time.Now()
	response, err := h.client.Create(key, string(data), ttl)
	metrics.RecordEtcdRequestLatency("create", getTypeName(obj), startTime)
	if err != nil {
		return err
	}
	if out != nil {
		if _, err := conversion.EnforcePtr(out); err != nil {
			panic("unable to convert output object to pointer")
		}
		_, _, err = h.extractObj(response, err, out, false, false)
	}
	return err
}

// ExtractList returns obj's Items element as an array of runtime.Objects.
// Returns an error if obj is not a List type (does not have an Items member).
func ExtractList(obj runtime.Object) ([]runtime.Object, error) {
	itemsPtr, err := GetItemsPtr(obj)
	if err != nil {
		return nil, err
	}
	items, err := conversion.EnforcePtr(itemsPtr)
	if err != nil {
		return nil, err
	}
	list := make([]runtime.Object, items.Len())
	for i := range list {
		raw := items.Index(i)
		switch item := raw.Interface().(type) {
		case runtime.RawExtension:
			switch {
			case item.Object != nil:
				list[i] = item.Object
			case item.Raw != nil:
				// TODO: Set ContentEncoding and ContentType correctly.
				list[i] = &runtime.Unknown{Raw: item.Raw}
			default:
				list[i] = nil
			}
		case runtime.Object:
			list[i] = item
		default:
			var found bool
			if list[i], found = raw.Addr().Interface().(runtime.Object); !found {
				return nil, fmt.Errorf("%v: item[%v]: Expected object, got %#v(%s)", obj, i, raw.Interface(), raw.Kind())
			}
		}
	}
	return list, nil
}

func ListAccessor(obj interface{}) (List, error) {
	if listMetaAccessor, ok := obj.(ListMetaAccessor); ok {
		if om := listMetaAccessor.GetListMeta(); om != nil {
			return om, nil
		}
	}
	// we may get passed an object that is directly portable to List
	if list, ok := obj.(List); ok {
		return list, nil
	}
	glog.V(4).Infof("Calling ListAccessor on non-internal object: %v", reflect.TypeOf(obj))
	// legacy path for objects that do not implement List and ListMetaAccessor via
	// reflection - very slow code path.
	v, err := conversion.EnforcePtr(obj)
	if err != nil {
		return nil, err
	}
	t := v.Type()
	if v.Kind() != reflect.Struct {
		return nil, fmt.Errorf("expected struct, but got %v: %v (%#v)", v.Kind(), t, v.Interface())
	}
	a := &genericAccessor{}
	listMeta := v.FieldByName("ListMeta")
	if listMeta.IsValid() {
		// look for the ListMeta fields
		if err := extractFromListMeta(listMeta, a); err != nil {
			return nil, fmt.Errorf("unable to find list fields on %#v: %v", listMeta, err)
		}
	} else {
		return nil, fmt.Errorf("unable to find listMeta on %#v", v)
	}
	return a, nil
}

// Implements storage.Interface.
func (h *etcdHelper) Create(ctx context.Context, key string, obj, out runtime.Object, ttl uint64) error {
	if ctx == nil {
		glog.Errorf("Context is nil")
	}
	key = h.prefixEtcdKey(key)
	data, err := runtime.Encode(h.codec, obj)
	if err != nil {
		return err
	}
	if h.versioner != nil {
		if version, err := h.versioner.ObjectResourceVersion(obj); err == nil && version != 0 {
			return errors.New("resourceVersion may not be set on objects to be created")
		}
	}

	startTime := time.Now()
	opts := etcd.SetOptions{
		TTL:       time.Duration(ttl) * time.Second,
		PrevExist: etcd.PrevNoExist,
	}
	response, err := h.client.Set(ctx, key, string(data), &opts)
	metrics.RecordEtcdRequestLatency("create", getTypeName(obj), startTime)
	if err != nil {
		return err
	}
	if out != nil {
		if _, err := conversion.EnforcePtr(out); err != nil {
			panic("unable to convert output object to pointer")
		}
		_, _, err = h.extractObj(response, err, out, false, false)
	}
	return err
}

func (h *etcdHelper) extractObj(response *etcd.Response, inErr error, objPtr runtime.Object, ignoreNotFound, prevNode bool) (body string, node *etcd.Node, err error) {
	if response != nil {
		if prevNode {
			node = response.PrevNode
		} else {
			node = response.Node
		}
	}
	if inErr != nil || node == nil || len(node.Value) == 0 {
		if ignoreNotFound {
			v, err := conversion.EnforcePtr(objPtr)
			if err != nil {
				return "", nil, err
			}
			v.Set(reflect.Zero(v.Type()))
			return "", nil, nil
		} else if inErr != nil {
			return "", nil, inErr
		}
		return "", nil, fmt.Errorf("unable to locate a value on the response: %#v", response)
	}
	body = node.Value
	out, gvk, err := h.codec.Decode([]byte(body), nil, objPtr)
	if err != nil {
		return body, nil, err
	}
	if out != objPtr {
		return body, nil, fmt.Errorf("unable to decode object %s into %v", gvk.String(), reflect.TypeOf(objPtr))
	}
	// being unable to set the version does not prevent the object from being extracted
	_ = h.versioner.UpdateObject(objPtr, node.Expiration, node.ModifiedIndex)
	return body, node, err
}

// Implements List (signature from storage.Interface).
func (c *Cacher) List(key string, listObj runtime.Object) error {
	listPtr, err := runtime.GetItemsPtr(listObj)
	if err != nil {
		return err
	}
	listVal, err := conversion.EnforcePtr(listPtr)
	if err != nil || listVal.Kind() != reflect.Slice {
		return fmt.Errorf("need a pointer to slice, got %v", listVal.Kind())
	}
	filter := filterFunction(key, c.keyFunc, Everything)

	objs, resourceVersion := c.watchCache.ListWithVersion()
	for _, obj := range objs {
		object, ok := obj.(runtime.Object)
		if !ok {
			return fmt.Errorf("non runtime.Object returned from storage: %v", obj)
		}
		if filter(object) {
			listVal.Set(reflect.Append(listVal, reflect.ValueOf(object).Elem()))
		}
	}
	if c.versioner != nil {
		if err := c.versioner.UpdateList(listObj, resourceVersion); err != nil {
			return err
		}
	}
	return nil
}

// ListFromMemory implements list operation (the same signature as List method)
// but it serves the contents from memory.
// Current we cannot use ListFromMemory() instead of List(), because it only
// guarantees eventual consistency (e.g. it's possible for Get called right after
// Create to return not-exist, before the change is propagate).
// TODO: We may consider changing to use ListFromMemory in the future, but this
// requires wider discussion as an "api semantic change".
func (c *Cacher) ListFromMemory(key string, listObj runtime.Object) error {
	// Do NOT allow Watch to start when the underlying structures are not propagated.
	c.usable.RLock()
	defer c.usable.RUnlock()

	listPtr, err := runtime.GetItemsPtr(listObj)
	if err != nil {
		return err
	}
	listVal, err := conversion.EnforcePtr(listPtr)
	if err != nil || listVal.Kind() != reflect.Slice {
		return fmt.Errorf("need a pointer to slice, got %v", listVal.Kind())
	}
	filter := filterFunction(key, c.keyFunc, Everything)

	objs, resourceVersion := c.watchCache.ListWithVersion()
	for _, obj := range objs {
		object, ok := obj.(runtime.Object)
		if !ok {
			return fmt.Errorf("non runtime.Object returned from storage: %v", obj)
		}
		if filter(object) {
			listVal.Set(reflect.Append(listVal, reflect.ValueOf(object).Elem()))
		}
	}
	if c.versioner != nil {
		if err := c.versioner.UpdateList(listObj, resourceVersion); err != nil {
			return err
		}
	}
	return nil
}

// ExtractList returns obj's Items element as an array of runtime.Objects.
// Returns an error if obj is not a List type (does not have an Items member).
// TODO: move me to pkg/api/meta
func ExtractList(obj Object) ([]Object, error) {
	itemsPtr, err := GetItemsPtr(obj)
	if err != nil {
		return nil, err
	}
	items, err := conversion.EnforcePtr(itemsPtr)
	if err != nil {
		return nil, err
	}
	list := make([]Object, items.Len())
	for i := range list {
		raw := items.Index(i)
		var found bool
		switch raw.Kind() {
		case reflect.Interface, reflect.Ptr:
			list[i], found = raw.Interface().(Object)
		default:
			list[i], found = raw.Addr().Interface().(Object)
		}
		if !found {
			return nil, fmt.Errorf("item[%v]: Expected object, got %#v(%s)", i, raw.Interface(), raw.Kind())
		}
	}
	return list, nil
}

// Implements storage.Interface.
func (c *Cacher) List(ctx context.Context, key string, resourceVersion string, pred SelectionPredicate, listObj runtime.Object) error {
	if resourceVersion == "" {
		// If resourceVersion is not specified, serve it from underlying
		// storage (for backward compatibility).
		return c.storage.List(ctx, key, resourceVersion, pred, listObj)
	}

	// If resourceVersion is specified, serve it from cache.
	// It's guaranteed that the returned value is at least that
	// fresh as the given resourceVersion.
	listRV, err := ParseListResourceVersion(resourceVersion)
	if err != nil {
		return err
	}

	trace := util.NewTrace(fmt.Sprintf("cacher %v: List", c.objectType.String()))
	defer trace.LogIfLong(500 * time.Millisecond)

	c.ready.wait()
	trace.Step("Ready")

	// List elements with at least 'listRV' from cache.
	listPtr, err := meta.GetItemsPtr(listObj)
	if err != nil {
		return err
	}
	listVal, err := conversion.EnforcePtr(listPtr)
	if err != nil || listVal.Kind() != reflect.Slice {
		return fmt.Errorf("need a pointer to slice, got %v", listVal.Kind())
	}
	filter := filterFunction(key, pred)

	objs, readResourceVersion, err := c.watchCache.WaitUntilFreshAndList(listRV, trace)
	if err != nil {
		return fmt.Errorf("failed to wait for fresh list: %v", err)
	}
	trace.Step(fmt.Sprintf("Listed %d items from cache", len(objs)))
	if len(objs) > listVal.Cap() && pred.Label.Empty() && pred.Field.Empty() {
		// Resize the slice appropriately, since we already know that none
		// of the elements will be filtered out.
		listVal.Set(reflect.MakeSlice(reflect.SliceOf(c.objectType.Elem()), 0, len(objs)))
		trace.Step("Resized result")
	}
	for _, obj := range objs {
		elem, ok := obj.(*storeElement)
		if !ok {
			return fmt.Errorf("non *storeElement returned from storage: %v", obj)
		}
		if filter(elem.Key, elem.Object) {
			listVal.Set(reflect.Append(listVal, reflect.ValueOf(elem.Object).Elem()))
		}
	}
	trace.Step(fmt.Sprintf("Filtered %d items", listVal.Len()))
	if c.versioner != nil {
		if err := c.versioner.UpdateList(listObj, readResourceVersion); err != nil {
			return err
		}
	}
	return nil
}

// SetZeroValue would set the object of objPtr to zero value of its type.
func SetZeroValue(objPtr Object) error {
	v, err := conversion.EnforcePtr(objPtr)
	if err != nil {
		return err
	}
	v.Set(reflect.Zero(v.Type()))
	return nil
}

// GuaranteedUpdate implements storage.Interface.GuaranteedUpdate.
func (s *store) GuaranteedUpdate(ctx context.Context, key string, out runtime.Object, ignoreNotFound bool, precondtions *storage.Preconditions, tryUpdate storage.UpdateFunc) error {
	v, err := conversion.EnforcePtr(out)
	if err != nil {
		panic("unable to convert output object to pointer")
	}
	key = keyWithPrefix(s.pathPrefix, key)
	getResp, err := s.client.KV.Get(ctx, key)
	if err != nil {
		return err
	}
	for {
		origState, err := s.getState(getResp, key, v, ignoreNotFound)
		if err != nil {
			return err
		}

		if err := checkPreconditions(key, precondtions, origState.obj); err != nil {
			return err
		}

		ret, ttl, err := s.updateState(origState, tryUpdate)
		if err != nil {
			return err
		}

		data, err := runtime.Encode(s.codec, ret)
		if err != nil {
			return err
		}
		if bytes.Equal(data, origState.data) {
			return decode(s.codec, s.versioner, origState.data, out, origState.rev)
		}

		opts, err := s.ttlOpts(ctx, int64(ttl))
		if err != nil {
			return err
		}

		txnResp, err := s.client.KV.Txn(ctx).If(
			clientv3.Compare(clientv3.ModRevision(key), "=", origState.rev),
		).Then(
			clientv3.OpPut(key, string(data), opts...),
		).Else(
			clientv3.OpGet(key),
		).Commit()
		if err != nil {
			return err
		}
		if !txnResp.Succeeded {
			getResp = (*clientv3.GetResponse)(txnResp.Responses[0].GetResponseRange())
			glog.V(4).Infof("GuaranteedUpdate of %s failed because of a conflict, going to retry", key)
			continue
		}
		putResp := txnResp.Responses[0].GetResponsePut()
		return decode(s.codec, s.versioner, data, out, putResp.Header.Revision)
	}
}

// ListMetaFor returns a pointer to a provided object's ListMeta,
// or an error if the object does not have that pointer.
// TODO: allow runtime.Unknown to extract this object
func ListMetaFor(obj runtime.Object) (*unversioned.ListMeta, error) {
	v, err := conversion.EnforcePtr(obj)
	if err != nil {
		return nil, err
	}
	var meta *unversioned.ListMeta
	err = runtime.FieldPtr(v, "ListMeta", &meta)
	return meta, err
}