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// Copyright (c) 2018, Sylabs Inc. All rights reserved.
// This software is licensed under a 3-clause BSD license. Please consult the
// LICENSE.md file distributed with the sources of this project regarding your
// rights to use or distribute this software.
package mount
import (
"fmt"
)
// hookFn describes function prototype for function
// to be called before/after mounting a tag list
type hookFn func(*System) error
// mountFn describes function prototype for function responsible
// of mount operation
type mountFn func(*Point, *System) error
// System defines a mount system allowing to register before/after
// hook functions for specific tag during mount phase
type System struct {
Points *Points
Mount mountFn
currentTag AuthorizedTag
beforeTagHooks map[AuthorizedTag][]hookFn
afterTagHooks map[AuthorizedTag][]hookFn
}
func (b *System) init() {
if b.beforeTagHooks == nil {
b.beforeTagHooks = make(map[AuthorizedTag][]hookFn)
}
if b.afterTagHooks == nil {
b.afterTagHooks = make(map[AuthorizedTag][]hookFn)
}
}
// RunBeforeTag registers a hook function executed before mounting points
// of tag list
func (b *System) RunBeforeTag(tag AuthorizedTag, fn hookFn) error {
if _, ok := authorizedTags[tag]; !ok {
return fmt.Errorf("tag %s is not an authorized tag", tag)
}
b.init()
b.beforeTagHooks[tag] = append(b.beforeTagHooks[tag], fn)
return nil
}
// RunAfterTag registers a hook function executed after mounting points
// of tag list
func (b *System) RunAfterTag(tag AuthorizedTag, fn hookFn) error {
if _, ok := authorizedTags[tag]; !ok {
return fmt.Errorf("tag %s is not an authorized tag", tag)
}
b.init()
b.afterTagHooks[tag] = append(b.afterTagHooks[tag], fn)
return nil
}
// CurrentTag returns the tag being processed by MountAll.
func (b *System) CurrentTag() AuthorizedTag {
return b.currentTag
}
// MountAll iterates over mount point list and mounts every point
// by calling hook before/after hook functions
func (b *System) MountAll() error {
b.init()
for _, tag := range GetTagList() {
b.currentTag = tag
for _, fn := range b.beforeTagHooks[tag] {
if err := fn(b); err != nil {
return fmt.Errorf("hook function for tag %s returns error: %s", tag, err)
}
}
for _, point := range b.Points.GetByTag(tag) {
p := point
if b.Mount != nil {
if err := b.Mount(&p, b); err != nil {
return fmt.Errorf("mount %s->%s error: %s", p.Source, p.Destination, err)
}
}
}
for _, fn := range b.afterTagHooks[tag] {
if err := fn(b); err != nil {
return fmt.Errorf("hook function for tag %s returns error: %s", tag, err)
}
}
}
return nil
}
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