sarulabs/di

package di

import (
    "errors"
    "fmt"
)

// containerLineage contains all the functions that are useful
// to retrieve or create the parent and children of a container.
type containerLineage struct{}

func (l *containerLineage) Parent(ctn *container) Container {
    return l.parent(ctn)
}

func (l *containerLineage) parent(ctn *container) *container {
    ctn.m.RLock()
    parent := ctn.containerCore.parent
    ctn.m.RUnlock()

    return &container{
        containerCore: parent,
    }
}

func (l *containerLineage) SubContainer(ctn *container) (Container, error) {
    child, err := l.createChild(ctn)
    if err != nil {
        return nil, err
    }

    ctn.m.Lock()

    if ctn.closed {
        ctn.m.Unlock()
        return nil, errors.New("the container is closed")
    }

    ctn.children[child.containerCore] = struct{}{}

    ctn.m.Unlock()

    return child, nil
}

func (l *containerLineage) createChild(ctn *container) (*container, error) {
    subscopes := ctn.SubScopes()

    if len(subscopes) == 0 {
        return nil, fmt.Errorf("there is no more specific scope than `%s`", ctn.scope)
    }

    return &container{
        containerCore: &containerCore{
            scope:         subscopes[0],
            scopes:        ctn.scopes,
            definitions:   ctn.definitions,
            parent:        ctn.containerCore,
            children:      map[*containerCore]struct{}{},
            unscopedChild: nil,
            objects:       map[objectKey]interface{}{},
            dependencies:  newGraph(),
        },
    }, nil
}