backend/internal/system/style.go

package system

import "git.tebibyte.media/tomo/tomo"

type styleApplicator struct {
	style *tomo.Style
	role  tomo.Role
	rules []*tomo.Rule
}

func (this *styleApplicator) apply (box anyBox) {
	if box.Role() != this.role {
		// the role has changed, so re-cache the list of rules
		this.rules = make([]*tomo.Rule, 0, 4)
		for _, rule := range this.style.Rules {
			role := box.Role()
			// blank fields match anything
			if rule.Role.Package == "" { role.Package = "" }
			if rule.Role.Object  == "" { role.Object  = "" }
			if rule.Role == role {
				this.rules = append(this.rules, &rule)
			}
		}
	}

	// compile list of attributes by searching through the cached ruleset
	attrs := make(tomo.AttrSet)
	for _, rule := range this.rules {
		satisifed := true
		if rule.Tags != nil {
			for _, tag := range rule.Tags {
				if !box.Tag(tag) {
					satisifed = false
					break
				}
			}
		}

		if satisifed {
			attrs.MergeOver(rule.Set)
		}
	}

	// apply that list of attributes
	for _, attr := range attrs {
		box.setAttr(attr, false)
	}
}