hugo/hugolib/hugo_sites.go

// Copyright 2019 The Hugo Authors. 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 hugolib

import (
	"fmt"
	"io"
	"path"
	"path/filepath"
	"sort"
	"strings"
	"sync"

	"github.com/gohugoio/hugo/output"
	"github.com/gohugoio/hugo/parser/metadecoders"

	"github.com/gohugoio/hugo/hugofs"

	"github.com/pkg/errors"

	"github.com/gohugoio/hugo/source"

	"github.com/bep/gitmap"
	"github.com/gohugoio/hugo/config"
	"github.com/spf13/afero"

	"github.com/gohugoio/hugo/publisher"

	"github.com/gohugoio/hugo/common/herrors"
	"github.com/gohugoio/hugo/common/loggers"
	"github.com/gohugoio/hugo/deps"
	"github.com/gohugoio/hugo/helpers"
	"github.com/gohugoio/hugo/langs"
	"github.com/gohugoio/hugo/lazy"

	"github.com/gohugoio/hugo/langs/i18n"
	"github.com/gohugoio/hugo/resources/page"
	"github.com/gohugoio/hugo/tpl"
	"github.com/gohugoio/hugo/tpl/tplimpl"
)

// HugoSites represents the sites to build. Each site represents a language.
type HugoSites struct {
	Sites []*Site

	multilingual *Multilingual

	// Multihost is set if multilingual and baseURL set on the language level.
	multihost bool

	// If this is running in the dev server.
	running bool

	// Serializes rebuilds when server is running.
	runningMu sync.Mutex

	// Render output formats for all sites.
	renderFormats output.Formats

	*deps.Deps

	gitInfo *gitInfo

	// As loaded from the /data dirs
	data map[string]interface{}

	// Keeps track of bundle directories and symlinks to enable partial rebuilding.
	ContentChanges *contentChangeMap

	init *hugoSitesInit

	*fatalErrorHandler
}

type fatalErrorHandler struct {
	mu sync.Mutex

	h *HugoSites

	err error

	done  bool
	donec chan bool // will be closed when done
}

// FatalError error is used in some rare situations where it does not make sense to
// continue processing, to abort as soon as possible and log the error.
func (f *fatalErrorHandler) FatalError(err error) {
	f.mu.Lock()
	defer f.mu.Unlock()
	if !f.done {
		f.done = true
		close(f.donec)
	}
	f.err = err
}

func (f *fatalErrorHandler) getErr() error {
	f.mu.Lock()
	defer f.mu.Unlock()
	return f.err
}

func (f *fatalErrorHandler) Done() <-chan bool {
	return f.donec
}

type hugoSitesInit struct {
	// Loads the data from all of the /data folders.
	data *lazy.Init

	// Loads the Git info for all the pages if enabled.
	gitInfo *lazy.Init

	// Maps page translations.
	translations *lazy.Init
}

func (h *hugoSitesInit) Reset() {
	h.data.Reset()
	h.gitInfo.Reset()
	h.translations.Reset()
}

func (h *HugoSites) Data() map[string]interface{} {
	if _, err := h.init.data.Do(); err != nil {
		h.SendError(errors.Wrap(err, "failed to load data"))
		return nil
	}
	return h.data
}

func (h *HugoSites) gitInfoForPage(p page.Page) (*gitmap.GitInfo, error) {
	if _, err := h.init.gitInfo.Do(); err != nil {
		return nil, err
	}

	if h.gitInfo == nil {
		return nil, nil
	}

	return h.gitInfo.forPage(p), nil
}

func (h *HugoSites) siteInfos() page.Sites {
	infos := make(page.Sites, len(h.Sites))
	for i, site := range h.Sites {
		infos[i] = &site.Info
	}
	return infos
}

func (h *HugoSites) pickOneAndLogTheRest(errors []error) error {
	if len(errors) == 0 {
		return nil
	}

	var i int

	for j, err := range errors {
		// If this is in server mode, we want to return an error to the client
		// with a file context, if possible.
		if herrors.UnwrapErrorWithFileContext(err) != nil {
			i = j
			break
		}
	}

	// Log the rest, but add a threshold to avoid flooding the log.
	const errLogThreshold = 5

	for j, err := range errors {
		if j == i || err == nil {
			continue
		}

		if j >= errLogThreshold {
			break
		}

		h.Log.ERROR.Println(err)
	}

	return errors[i]
}

func (h *HugoSites) IsMultihost() bool {
	return h != nil && h.multihost
}

func (h *HugoSites) LanguageSet() map[string]bool {
	set := make(map[string]bool)
	for _, s := range h.Sites {
		set[s.language.Lang] = true
	}
	return set
}

func (h *HugoSites) NumLogErrors() int {
	if h == nil {
		return 0
	}
	return int(h.Log.ErrorCounter.Count())
}

func (h *HugoSites) PrintProcessingStats(w io.Writer) {
	stats := make([]*helpers.ProcessingStats, len(h.Sites))
	for i := 0; i < len(h.Sites); i++ {
		stats[i] = h.Sites[i].PathSpec.ProcessingStats
	}
	helpers.ProcessingStatsTable(w, stats...)
}

func (h *HugoSites) langSite() map[string]*Site {
	m := make(map[string]*Site)
	for _, s := range h.Sites {
		m[s.language.Lang] = s
	}
	return m
}

// GetContentPage finds a Page with content given the absolute filename.
// Returns nil if none found.
func (h *HugoSites) GetContentPage(filename string) page.Page {
	for _, s := range h.Sites {
		pos := s.rawAllPages.findPagePosByFilename(filename)
		if pos == -1 {
			continue
		}
		return s.rawAllPages[pos]
	}

	// If not found already, this may be bundled in another content file.
	dir := filepath.Dir(filename)

	for _, s := range h.Sites {
		pos := s.rawAllPages.findPagePosByFilnamePrefix(dir)
		if pos == -1 {
			continue
		}
		return s.rawAllPages[pos]
	}
	return nil
}

// NewHugoSites creates a new collection of sites given the input sites, building
// a language configuration based on those.
func newHugoSites(cfg deps.DepsCfg, sites ...*Site) (*HugoSites, error) {

	if cfg.Language != nil {
		return nil, errors.New("Cannot provide Language in Cfg when sites are provided")
	}

	langConfig, err := newMultiLingualFromSites(cfg.Cfg, sites...)

	if err != nil {
		return nil, err
	}

	var contentChangeTracker *contentChangeMap

	h := &HugoSites{
		running:      cfg.Running,
		multilingual: langConfig,
		multihost:    cfg.Cfg.GetBool("multihost"),
		Sites:        sites,
		init: &hugoSitesInit{
			data:         lazy.New(),
			gitInfo:      lazy.New(),
			translations: lazy.New(),
		},
	}

	h.fatalErrorHandler = &fatalErrorHandler{
		h:     h,
		donec: make(chan bool),
	}

	h.init.data.Add(func() (interface{}, error) {
		err := h.loadData(h.PathSpec.BaseFs.Data.Fs)
		return err, nil
	})

	h.init.translations.Add(func() (interface{}, error) {
		if len(h.Sites) > 1 {
			allTranslations := pagesToTranslationsMap(h.Sites)
			assignTranslationsToPages(allTranslations, h.Sites)
		}

		return nil, nil
	})

	h.init.gitInfo.Add(func() (interface{}, error) {
		err := h.loadGitInfo()
		return nil, err
	})

	for _, s := range sites {
		s.h = h
	}

	if err := applyDeps(cfg, sites...); err != nil {
		return nil, err
	}

	h.Deps = sites[0].Deps

	// Only needed in server mode.
	// TODO(bep) clean up the running vs watching terms
	if cfg.Running {
		contentChangeTracker = &contentChangeMap{pathSpec: h.PathSpec, symContent: make(map[string]map[string]bool)}
		h.ContentChanges = contentChangeTracker
	}

	return h, nil
}

func (h *HugoSites) loadGitInfo() error {
	if h.Cfg.GetBool("enableGitInfo") {
		gi, err := newGitInfo(h.Cfg)
		if err != nil {
			h.Log.ERROR.Println("Failed to read Git log:", err)
		} else {
			h.gitInfo = gi
		}
	}
	return nil
}

func applyDeps(cfg deps.DepsCfg, sites ...*Site) error {
	if cfg.TemplateProvider == nil {
		cfg.TemplateProvider = tplimpl.DefaultTemplateProvider
	}

	if cfg.TranslationProvider == nil {
		cfg.TranslationProvider = i18n.NewTranslationProvider()
	}

	var (
		d   *deps.Deps
		err error
	)

	for _, s := range sites {
		if s.Deps != nil {
			continue
		}

		onCreated := func(d *deps.Deps) error {
			s.Deps = d

			// Set up the main publishing chain.
			s.publisher = publisher.NewDestinationPublisher(d.PathSpec.BaseFs.PublishFs, s.outputFormatsConfig, s.mediaTypesConfig, cfg.Cfg.GetBool("minify"))

			if err := s.initializeSiteInfo(); err != nil {
				return err
			}

			d.Site = &s.Info

			siteConfig, err := loadSiteConfig(s.language)
			if err != nil {
				return err
			}
			s.siteConfigConfig = siteConfig
			s.siteRefLinker, err = newSiteRefLinker(s.language, s)
			return err
		}

		cfg.Language = s.language
		cfg.MediaTypes = s.mediaTypesConfig
		cfg.OutputFormats = s.outputFormatsConfig

		if d == nil {
			cfg.WithTemplate = s.withSiteTemplates(cfg.WithTemplate)

			var err error
			d, err = deps.New(cfg)
			if err != nil {
				return err
			}

			d.OutputFormatsConfig = s.outputFormatsConfig

			if err := onCreated(d); err != nil {
				return err
			}

			if err = d.LoadResources(); err != nil {
				return err
			}

		} else {
			d, err = d.ForLanguage(cfg, onCreated)
			if err != nil {
				return err
			}
			d.OutputFormatsConfig = s.outputFormatsConfig
		}

	}

	return nil
}

// NewHugoSites creates HugoSites from the given config.
func NewHugoSites(cfg deps.DepsCfg) (*HugoSites, error) {
	sites, err := createSitesFromConfig(cfg)
	if err != nil {
		return nil, err
	}
	return newHugoSites(cfg, sites...)
}

func (s *Site) withSiteTemplates(withTemplates ...func(templ tpl.TemplateHandler) error) func(templ tpl.TemplateHandler) error {
	return func(templ tpl.TemplateHandler) error {
		if err := templ.LoadTemplates(""); err != nil {
			return err
		}

		for _, wt := range withTemplates {
			if wt == nil {
				continue
			}
			if err := wt(templ); err != nil {
				return err
			}
		}

		return nil
	}
}

func createSitesFromConfig(cfg deps.DepsCfg) ([]*Site, error) {

	var (
		sites []*Site
	)

	languages := getLanguages(cfg.Cfg)

	for _, lang := range languages {
		if lang.Disabled {
			continue
		}
		var s *Site
		var err error
		cfg.Language = lang
		s, err = newSite(cfg)

		if err != nil {
			return nil, err
		}

		sites = append(sites, s)
	}

	return sites, nil
}

// Reset resets the sites and template caches etc., making it ready for a full rebuild.
func (h *HugoSites) reset(config *BuildCfg) {
	if config.ResetState {
		for i, s := range h.Sites {
			h.Sites[i] = s.reset()
			if r, ok := s.Fs.Destination.(hugofs.Reseter); ok {
				r.Reset()
			}
		}
	}

	h.fatalErrorHandler = &fatalErrorHandler{
		h:     h,
		donec: make(chan bool),
	}

	h.init.Reset()
}

// resetLogs resets the log counters etc. Used to do a new build on the same sites.
func (h *HugoSites) resetLogs() {
	h.Log.Reset()
	loggers.GlobalErrorCounter.Reset()
	for _, s := range h.Sites {
		s.Deps.DistinctErrorLog = helpers.NewDistinctLogger(h.Log.ERROR)
	}
}

func (h *HugoSites) createSitesFromConfig(cfg config.Provider) error {
	oldLangs, _ := h.Cfg.Get("languagesSorted").(langs.Languages)

	if err := loadLanguageSettings(h.Cfg, oldLangs); err != nil {
		return err
	}

	depsCfg := deps.DepsCfg{Fs: h.Fs, Cfg: cfg}

	sites, err := createSitesFromConfig(depsCfg)

	if err != nil {
		return err
	}

	langConfig, err := newMultiLingualFromSites(depsCfg.Cfg, sites...)

	if err != nil {
		return err
	}

	h.Sites = sites

	for _, s := range sites {
		s.h = h
	}

	if err := applyDeps(depsCfg, sites...); err != nil {
		return err
	}

	h.Deps = sites[0].Deps

	h.multilingual = langConfig
	h.multihost = h.Deps.Cfg.GetBool("multihost")

	return nil
}

func (h *HugoSites) toSiteInfos() []*SiteInfo {
	infos := make([]*SiteInfo, len(h.Sites))
	for i, s := range h.Sites {
		infos[i] = &s.Info
	}
	return infos
}

// BuildCfg holds build options used to, as an example, skip the render step.
type BuildCfg struct {
	// Reset site state before build. Use to force full rebuilds.
	ResetState bool
	// If set, we re-create the sites from the given configuration before a build.
	// This is needed if new languages are added.
	NewConfig config.Provider
	// Skip rendering. Useful for testing.
	SkipRender bool
	// Use this to indicate what changed (for rebuilds).
	whatChanged *whatChanged

	// This is a partial re-render of some selected pages. This means
	// we should skip most of the processing.
	PartialReRender bool

	// Recently visited URLs. This is used for partial re-rendering.
	RecentlyVisited map[string]bool
}

// shouldRender is used in the Fast Render Mode to determine if we need to re-render
// a Page: If it is recently visited (the home pages will always be in this set) or changed.
// Note that a page does not have to have a content page / file.
// For regular builds, this will allways return true.
// TODO(bep) rename/work this.
func (cfg *BuildCfg) shouldRender(p *pageState) bool {
	if !p.render {
		return false
	}
	if p.forceRender {
		return true
	}

	if len(cfg.RecentlyVisited) == 0 {
		return true
	}

	if cfg.RecentlyVisited[p.RelPermalink()] {
		return true
	}

	if cfg.whatChanged != nil && !p.File().IsZero() {
		return cfg.whatChanged.files[p.File().Filename()]
	}

	return false
}

func (h *HugoSites) renderCrossSitesArtifacts() error {

	if !h.multilingual.enabled() || h.IsMultihost() {
		return nil
	}

	sitemapEnabled := false
	for _, s := range h.Sites {
		if s.isEnabled(kindSitemap) {
			sitemapEnabled = true
			break
		}
	}

	if !sitemapEnabled {
		return nil
	}

	s := h.Sites[0]

	smLayouts := []string{"sitemapindex.xml", "_default/sitemapindex.xml", "_internal/_default/sitemapindex.xml"}

	return s.renderAndWriteXML(&s.PathSpec.ProcessingStats.Sitemaps, "sitemapindex",
		s.siteCfg.sitemap.Filename, h.toSiteInfos(), smLayouts...)
}

// createMissingPages creates home page, taxonomies etc. that isnt't created as an
// effect of having a content file.
func (h *HugoSites) createMissingPages() error {

	for _, s := range h.Sites {
		if s.isEnabled(page.KindHome) {
			// home pages
			homes := s.findWorkPagesByKind(page.KindHome)
			if len(homes) > 1 {
				panic("Too many homes")
			}
			var home *pageState
			if len(homes) == 0 {
				home = s.newPage(page.KindHome)
				s.workAllPages = append(s.workAllPages, home)
			} else {
				home = homes[0]
			}

			s.home = home
		}

		// Will create content-less root sections.
		newSections := s.assembleSections()
		s.workAllPages = append(s.workAllPages, newSections...)

		taxonomyTermEnabled := s.isEnabled(page.KindTaxonomyTerm)
		taxonomyEnabled := s.isEnabled(page.KindTaxonomy)

		// taxonomy list and terms pages
		taxonomies := s.Language().GetStringMapString("taxonomies")
		if len(taxonomies) > 0 {
			taxonomyPages := s.findWorkPagesByKind(page.KindTaxonomy)
			taxonomyTermsPages := s.findWorkPagesByKind(page.KindTaxonomyTerm)

			// Make them navigable from WeightedPage etc.
			for _, p := range taxonomyPages {
				ni := p.getTaxonomyNodeInfo()
				if ni == nil {
					// This can be nil for taxonomies, e.g. an author,
					// with a content file, but no actual usage.
					// Create one.
					sections := p.SectionsEntries()
					if len(sections) < 2 {
						// Invalid state
						panic(fmt.Sprintf("invalid taxonomy state for %q with sections %v", p.pathOrTitle(), sections))
					}
					ni = p.s.taxonomyNodes.GetOrAdd(sections[0], path.Join(sections[1:]...))
				}
				ni.TransferValues(p)
			}
			for _, p := range taxonomyTermsPages {
				p.getTaxonomyNodeInfo().TransferValues(p)
			}

			for _, plural := range taxonomies {
				if taxonomyTermEnabled {
					foundTaxonomyTermsPage := false
					for _, p := range taxonomyTermsPages {
						if p.SectionsPath() == plural {
							foundTaxonomyTermsPage = true
							break
						}
					}

					if !foundTaxonomyTermsPage {
						n := s.newPage(page.KindTaxonomyTerm, plural)
						n.getTaxonomyNodeInfo().TransferValues(n)
						s.workAllPages = append(s.workAllPages, n)
					}
				}

				if taxonomyEnabled {
					for termKey := range s.Taxonomies[plural] {

						foundTaxonomyPage := false

						for _, p := range taxonomyPages {
							sectionsPath := p.SectionsPath()

							if !strings.HasPrefix(sectionsPath, plural) {
								continue
							}

							singularKey := strings.TrimPrefix(sectionsPath, plural)
							singularKey = strings.TrimPrefix(singularKey, "/")

							if singularKey == termKey {
								foundTaxonomyPage = true
								break
							}
						}

						if !foundTaxonomyPage {
							info := s.taxonomyNodes.Get(plural, termKey)
							if info == nil {
								panic("no info found")
							}

							n := s.newTaxonomyPage(info.term, info.plural, info.termKey)
							info.TransferValues(n)
							s.workAllPages = append(s.workAllPages, n)
						}
					}
				}
			}
		}
	}

	return nil
}

func (h *HugoSites) removePageByFilename(filename string) {
	for _, s := range h.Sites {
		s.removePageFilename(filename)
	}
}

func (h *HugoSites) createPageCollections() error {
	for _, s := range h.Sites {
		for _, p := range s.rawAllPages {
			if !s.isEnabled(p.Kind()) {
				continue
			}

			shouldBuild := s.shouldBuild(p)
			s.buildStats.update(p)
			if shouldBuild {
				if p.m.headless {
					s.headlessPages = append(s.headlessPages, p)
				} else {
					s.workAllPages = append(s.workAllPages, p)
				}
			}
		}
	}

	allPages := newLazyPagesFactory(func() page.Pages {
		var pages page.Pages
		for _, s := range h.Sites {
			pages = append(pages, s.Pages()...)
		}

		page.SortByDefault(pages)

		return pages
	})

	allRegularPages := newLazyPagesFactory(func() page.Pages {
		return h.findPagesByKindIn(page.KindPage, allPages.get())
	})

	for _, s := range h.Sites {
		s.PageCollections.allPages = allPages
		s.PageCollections.allRegularPages = allRegularPages
	}

	return nil
}

func (s *Site) preparePagesForRender(isRenderingSite bool, idx int) error {

	for _, p := range s.workAllPages {
		if err := p.initOutputFormat(isRenderingSite, idx); err != nil {
			return err
		}
	}

	for _, p := range s.headlessPages {
		if err := p.initOutputFormat(isRenderingSite, idx); err != nil {
			return err
		}
	}

	return nil
}

// Pages returns all pages for all sites.
func (h *HugoSites) Pages() page.Pages {
	return h.Sites[0].AllPages()
}

func (h *HugoSites) loadData(fs afero.Fs) (err error) {
	spec := source.NewSourceSpec(h.PathSpec, fs)
	fileSystem := spec.NewFilesystem("")
	h.data = make(map[string]interface{})
	for _, r := range fileSystem.Files() {
		if err := h.handleDataFile(r); err != nil {
			return err
		}
	}

	return
}

func (h *HugoSites) handleDataFile(r source.ReadableFile) error {
	var current map[string]interface{}

	f, err := r.Open()
	if err != nil {
		return errors.Wrapf(err, "Failed to open data file %q:", r.LogicalName())
	}
	defer f.Close()

	// Crawl in data tree to insert data
	current = h.data
	keyParts := strings.Split(r.Dir(), helpers.FilePathSeparator)
	// The first path element is the virtual folder (typically theme name), which is
	// not part of the key.
	if len(keyParts) > 1 {
		for _, key := range keyParts[1:] {
			if key != "" {
				if _, ok := current[key]; !ok {
					current[key] = make(map[string]interface{})
				}
				current = current[key].(map[string]interface{})
			}
		}
	}

	data, err := h.readData(r)
	if err != nil {
		return h.errWithFileContext(err, r)
	}

	if data == nil {
		return nil
	}

	// filepath.Walk walks the files in lexical order, '/' comes before '.'
	// this warning could happen if
	// 1. A theme uses the same key; the main data folder wins
	// 2. A sub folder uses the same key: the sub folder wins
	higherPrecedentData := current[r.BaseFileName()]

	switch data.(type) {
	case nil:
		// hear the crickets?

	case map[string]interface{}:

		switch higherPrecedentData.(type) {
		case nil:
			current[r.BaseFileName()] = data
		case map[string]interface{}:
			// merge maps: insert entries from data for keys that
			// don't already exist in higherPrecedentData
			higherPrecedentMap := higherPrecedentData.(map[string]interface{})
			for key, value := range data.(map[string]interface{}) {
				if _, exists := higherPrecedentMap[key]; exists {
					h.Log.WARN.Printf("Data for key '%s' in path '%s' is overridden by higher precedence data already in the data tree", key, r.Path())
				} else {
					higherPrecedentMap[key] = value
				}
			}
		default:
			// can't merge: higherPrecedentData is not a map
			h.Log.WARN.Printf("The %T data from '%s' overridden by "+
				"higher precedence %T data already in the data tree", data, r.Path(), higherPrecedentData)
		}

	case []interface{}:
		if higherPrecedentData == nil {
			current[r.BaseFileName()] = data
		} else {
			// we don't merge array data
			h.Log.WARN.Printf("The %T data from '%s' overridden by "+
				"higher precedence %T data already in the data tree", data, r.Path(), higherPrecedentData)
		}

	default:
		h.Log.ERROR.Printf("unexpected data type %T in file %s", data, r.LogicalName())
	}

	return nil
}

func (h *HugoSites) errWithFileContext(err error, f source.File) error {
	rfi, ok := f.FileInfo().(hugofs.RealFilenameInfo)
	if !ok {
		return err
	}

	realFilename := rfi.RealFilename()

	err, _ = herrors.WithFileContextForFile(
		err,
		realFilename,
		realFilename,
		h.SourceSpec.Fs.Source,
		herrors.SimpleLineMatcher)

	return err
}

func (h *HugoSites) readData(f source.ReadableFile) (interface{}, error) {
	file, err := f.Open()
	if err != nil {
		return nil, errors.Wrap(err, "readData: failed to open data file")
	}
	defer file.Close()
	content := helpers.ReaderToBytes(file)

	format := metadecoders.FormatFromString(f.Extension())
	return metadecoders.Default.Unmarshal(content, format)
}

func (h *HugoSites) findPagesByKindIn(kind string, inPages page.Pages) page.Pages {
	return h.Sites[0].findPagesByKindIn(kind, inPages)
}

func (h *HugoSites) findPagesByShortcode(shortcode string) page.Pages {
	var pages page.Pages
	for _, s := range h.Sites {
		pages = append(pages, s.findPagesByShortcode(shortcode)...)
	}
	return pages
}

// Used in partial reloading to determine if the change is in a bundle.
type contentChangeMap struct {
	mu       sync.RWMutex
	branches []string
	leafs    []string

	pathSpec *helpers.PathSpec

	// Hugo supports symlinked content (both directories and files). This
	// can lead to situations where the same file can be referenced from several
	// locations in /content -- which is really cool, but also means we have to
	// go an extra mile to handle changes.
	// This map is only used in watch mode.
	// It maps either file to files or the real dir to a set of content directories where it is in use.
	symContent   map[string]map[string]bool
	symContentMu sync.Mutex
}

func (m *contentChangeMap) add(filename string, tp bundleDirType) {
	m.mu.Lock()
	dir := filepath.Dir(filename) + helpers.FilePathSeparator
	dir = strings.TrimPrefix(dir, ".")
	switch tp {
	case bundleBranch:
		m.branches = append(m.branches, dir)
	case bundleLeaf:
		m.leafs = append(m.leafs, dir)
	default:
		panic("invalid bundle type")
	}
	m.mu.Unlock()
}

// Track the addition of bundle dirs.
func (m *contentChangeMap) handleBundles(b *bundleDirs) {
	for _, bd := range b.bundles {
		m.add(bd.fi.Path(), bd.tp)
	}
}

// resolveAndRemove resolves the given filename to the root folder of a bundle, if relevant.
// It also removes the entry from the map. It will be re-added again by the partial
// build if it still is a bundle.
func (m *contentChangeMap) resolveAndRemove(filename string) (string, string, bundleDirType) {
	m.mu.RLock()
	defer m.mu.RUnlock()

	// Bundles share resources, so we need to start from the virtual root.
	relPath := m.pathSpec.RelContentDir(filename)
	dir, name := filepath.Split(relPath)
	if !strings.HasSuffix(dir, helpers.FilePathSeparator) {
		dir += helpers.FilePathSeparator
	}

	fileTp, isContent := classifyBundledFile(name)

	// This may be a member of a bundle. Start with branch bundles, the most specific.
	if fileTp == bundleBranch || (fileTp == bundleNot && !isContent) {
		for i, b := range m.branches {
			if b == dir {
				m.branches = append(m.branches[:i], m.branches[i+1:]...)
				return dir, b, bundleBranch
			}
		}
	}

	// And finally the leaf bundles, which can contain anything.
	for i, l := range m.leafs {
		if strings.HasPrefix(dir, l) {
			m.leafs = append(m.leafs[:i], m.leafs[i+1:]...)
			return dir, l, bundleLeaf
		}
	}

	if isContent && fileTp != bundleNot {
		// A new bundle.
		return dir, dir, fileTp
	}

	// Not part of any bundle
	return dir, filename, bundleNot
}

func (m *contentChangeMap) addSymbolicLinkMapping(from, to string) {
	m.symContentMu.Lock()
	mm, found := m.symContent[from]
	if !found {
		mm = make(map[string]bool)
		m.symContent[from] = mm
	}
	mm[to] = true
	m.symContentMu.Unlock()
}

func (m *contentChangeMap) GetSymbolicLinkMappings(dir string) []string {
	mm, found := m.symContent[dir]
	if !found {
		return nil
	}
	dirs := make([]string, len(mm))
	i := 0
	for dir := range mm {
		dirs[i] = dir
		i++
	}

	sort.Strings(dirs)
	return dirs
}