source: code/trunk/vendor/github.com/yosssi/gcss/element_base.go@ 75

package gcss

import (
        "bytes"
        "io"
)

// elementBase holds the common fields of an element.
type elementBase struct {
        ln     *line
        parent element
        sels   []*selector
        decs   []*declaration
        mixins []*mixinInvocation
        ctx    *context
}

// AppendChild appends a child element to the element.
func (eBase *elementBase) AppendChild(child element) {
        switch c := child.(type) {
        case *mixinInvocation:
                eBase.mixins = append(eBase.mixins, c)
        case *declaration:
                eBase.decs = append(eBase.decs, c)
        case *selector:
                eBase.sels = append(eBase.sels, c)
        }
}

// Base returns the element base.
func (eBase *elementBase) Base() *elementBase {
        return eBase
}

// SetContext sets the context to the element.
func (eBase *elementBase) SetContext(ctx *context) {
        eBase.ctx = ctx
}

// Context returns the top element's context.
func (eBase *elementBase) Context() *context {
        if eBase.parent != nil {
                return eBase.parent.Context()
        }

        return eBase.ctx
}

// hasMixinDecs returns true if the element has a mixin
// which has declarations.
func (eBase *elementBase) hasMixinDecs() bool {
        for _, mi := range eBase.mixins {
                if decs, _ := mi.decsParams(); len(decs) > 0 {
                        return true
                }
        }

        return false
}

// hasMixinSels returns true if the element has a mixin
// which has selectors.
func (eBase *elementBase) hasMixinSels() bool {
        for _, mi := range eBase.mixins {
                if sels, _ := mi.selsParams(); len(sels) > 0 {
                        return true
                }
        }

        return false
}

// writeDecsTo writes the element's declarations to w.
func (eBase *elementBase) writeDecsTo(w io.Writer, params map[string]string) (int64, error) {
        bf := new(bytes.Buffer)

        // Write the declarations.
        for _, dec := range eBase.decs {
                // Writing to the bytes.Buffer never returns an error.
                dec.writeTo(bf, params)
        }

        // Write the mixin's declarations.
        for _, mi := range eBase.mixins {
                decs, prms := mi.decsParams()

                for _, dec := range decs {
                        // Writing to the bytes.Buffer never returns an error.
                        dec.writeTo(bf, prms)
                }
        }

        n, err := w.Write(bf.Bytes())

        return int64(n), err
}

// newElementBase creates and returns an element base.
func newElementBase(ln *line, parent element) elementBase {
        return elementBase{
                ln:     ln,
                parent: parent,
        }
}