forked from google/cadvisor
/
factory.go
129 lines (110 loc) · 3.18 KB
/
factory.go
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// Copyright 2014 Google Inc. All Rights Reserved.
//
// Licensed under the Apache License, Version 2.0 (the "License");
// you may not use this file except in compliance with the License.
// You may obtain a copy of the License at
//
// http://www.apache.org/licenses/LICENSE-2.0
//
// Unless required by applicable law or agreed to in writing, software
// distributed under the License is distributed on an "AS IS" BASIS,
// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
// See the License for the specific language governing permissions and
// limitations under the License.
package container
import (
"fmt"
"log"
"strings"
"sync"
)
type ContainerHandlerFactory interface {
NewContainerHandler(name string) (ContainerHandler, error)
// for testability
String() string
}
type factoryTreeNode struct {
defaultFactory ContainerHandlerFactory
children map[string]*factoryTreeNode
}
func (self *factoryTreeNode) find(elems ...string) ContainerHandlerFactory {
node := self
for _, elem := range elems {
if len(node.children) == 0 {
break
}
if child, ok := node.children[elem]; ok {
node = child
} else {
return node.defaultFactory
}
}
return node.defaultFactory
}
func (self *factoryTreeNode) add(factory ContainerHandlerFactory, elems ...string) {
node := self
for _, elem := range elems {
if node.children == nil {
node.children = make(map[string]*factoryTreeNode, 16)
}
child, ok := self.children[elem]
if !ok {
child = &factoryTreeNode{
defaultFactory: node.defaultFactory,
children: make(map[string]*factoryTreeNode, 16),
}
node.children[elem] = child
}
node = child
}
node.defaultFactory = factory
}
type factoryManager struct {
root *factoryTreeNode
lock sync.RWMutex
}
func dropEmptyString(elems ...string) []string {
ret := make([]string, 0, len(elems))
for _, e := range elems {
if len(e) > 0 {
ret = append(ret, e)
}
}
return ret
}
// Must register factory for root container!
func (self *factoryManager) Register(path string, factory ContainerHandlerFactory) {
self.lock.Lock()
defer self.lock.Unlock()
if self.root == nil {
self.root = &factoryTreeNode{
defaultFactory: nil,
children: make(map[string]*factoryTreeNode, 10),
}
}
elems := dropEmptyString(strings.Split(path, "/")...)
self.root.add(factory, elems...)
}
func (self *factoryManager) NewContainerHandler(path string) (ContainerHandler, error) {
self.lock.RLock()
defer self.lock.RUnlock()
if self.root == nil {
err := fmt.Errorf("nil factory for container %v: no factory registered", path)
return nil, err
}
elems := dropEmptyString(strings.Split(path, "/")...)
factory := self.root.find(elems...)
if factory == nil {
err := fmt.Errorf("nil factory for container %v", path)
return nil, err
}
log.Printf("container handler factory for %v is %v\n", path, factory)
return factory.NewContainerHandler(path)
}
var globalFactoryManager factoryManager
func RegisterContainerHandlerFactory(path string, factory ContainerHandlerFactory) {
globalFactoryManager.Register(path, factory)
}
func NewContainerHandler(path string) (ContainerHandler, error) {
return globalFactoryManager.NewContainerHandler(path)
}