Simplify the content map key structure to ease finding stuff

Fixes gohugoio#8307
Fixes gohugoio#8498

common/herrors/errors.go

@@ -65,6 +65,7 @@ type ErrorSender interface {
 // Recover is a helper function that can be used to capture panics.
 // Put this at the top of a method/function that crashes in a template:
 //     defer herrors.Recover()
+// TODO1 check usage
 func Recover(args ...interface{}) {
 	if r := recover(); r != nil {
 		fmt.Println("ERR:", r)

common/types/types.go

@@ -90,3 +90,15 @@ func IsNil(v interface{}) bool {
 type DevMarker interface {
 	DevOnly()
 }
+
+// Identifier identifies a resource.
+type Identifier interface {
+	Key() string
+}
+
+// KeyString is a string that implements Identifier.
+type KeyString string
+
+func (k KeyString) Key() string {
+	return string(k)
+}

helpers/path.go

@@ -479,3 +479,18 @@ func AddTrailingSlash(path string) string {
 	}
 	return path
 }
+
+// AddLeadingSlash adds a leading Unix styled slash (/) if not already
+// there.
+func AddLeadingSlash(path string) string {
+	if !strings.HasPrefix(path, "/") {
+		path = "/" + path
+	}
+	return path
+}
+
+// AddLeadingAndTrailingSlash adds a leading and trailing Unix styled slash (/)
+// if not already there.
+func AddLeadingAndTrailingSlash(path string) string {
+	return AddTrailingSlash(AddLeadingSlash(path))
+}

hugofs/filter_fs.go

@@ -99,11 +99,19 @@ func NewLanguageFs(langs map[string]int, fs afero.Fs) (afero.Fs, error) {
 		}
 	}
 
-	return &FilterFs{
+	ffs := &FilterFs{
 		fs:             fs,
 		applyPerSource: applyMeta,
 		applyAll:       all,
-	}, nil
+	}
+
+	if rfs, ok := fs.(ReverseLookupProvider); ok {
+		// Preserve that interface.
+		return NewExtendedFs(ffs, rfs), nil
+	}
+
+	return ffs, nil
+
 }
 
 func NewFilterFs(fs afero.Fs) (afero.Fs, error) {
@@ -120,6 +128,11 @@ func NewFilterFs(fs afero.Fs) (afero.Fs, error) {
 		applyPerSource: applyMeta,
 	}
 
+	if rfs, ok := fs.(ReverseLookupProvider); ok {
+		// Preserve that interface.
+		return NewExtendedFs(ffs, rfs), nil
+	}
+
 	return ffs, nil
 }
 

hugofs/language_composite_fs.go

@@ -26,15 +26,21 @@ var (
 )
 
 type languageCompositeFs struct {
+	base    ExtendedFs
+	overlay ExtendedFs
 	*afero.CopyOnWriteFs
 }
 
 // NewLanguageCompositeFs creates a composite and language aware filesystem.
 // This is a hybrid filesystem. To get a specific file in Open, Stat etc., use the full filename
 // to the target filesystem. This information is available in Readdir, Stat etc. via the
 // special LanguageFileInfo FileInfo implementation.
-func NewLanguageCompositeFs(base, overlay afero.Fs) afero.Fs {
-	return &languageCompositeFs{afero.NewCopyOnWriteFs(base, overlay).(*afero.CopyOnWriteFs)}
+func NewLanguageCompositeFs(base, overlay ExtendedFs) ExtendedFs {
+	return &languageCompositeFs{
+		base:          base,
+		overlay:       overlay,
+		CopyOnWriteFs: afero.NewCopyOnWriteFs(base, overlay).(*afero.CopyOnWriteFs),
+	}
 }
 
 // Open takes the full path to the file in the target filesystem. If it is a directory, it gets merged
@@ -53,6 +59,16 @@ func (fs *languageCompositeFs) Open(name string) (afero.File, error) {
 	return f, nil
 }
 
+func (fs *languageCompositeFs) ReverseLookup(name string) (string, error) {
+	// Try the overlay first.
+	s, err := fs.overlay.ReverseLookup(name)
+	if s != "" || err != nil {
+		return s, err
+	}
+
+	return fs.base.ReverseLookup(name)
+}
+
 // LanguageDirsMerger implements the afero.DirsMerger interface, which is used
 // to merge two directories.
 var LanguageDirsMerger = func(lofi, bofi []os.FileInfo) ([]os.FileInfo, error) {

hugofs/rootmapping_fs.go

@@ -27,15 +27,48 @@ import (
 	"github.com/spf13/afero"
 )
 
+var _ ReverseLookupProvider = (*RootMappingFs)(nil)
+
+type ExtendedFs interface {
+	afero.Fs
+	ReverseLookupProvider
+}
+
+func NewExtendedFs(fs afero.Fs, rl ReverseLookupProvider) ExtendedFs {
+	return struct {
+		afero.Fs
+		ReverseLookupProvider
+	}{
+		fs,
+		rl,
+	}
+}
+
+type ReverseLookupProvider interface {
+	ReverseLookup(name string) (string, error)
+}
+
 var filepathSeparator = string(filepath.Separator)
 
 // NewRootMappingFs creates a new RootMappingFs on top of the provided with
 // root mappings with some optional metadata about the root.
 // Note that From represents a virtual root that maps to the actual filename in To.
 func NewRootMappingFs(fs afero.Fs, rms ...RootMapping) (*RootMappingFs, error) {
 	rootMapToReal := radix.New()
+	realMapToRoot := radix.New()
 	var virtualRoots []RootMapping
 
+	addMapping := func(key string, rm RootMapping, to *radix.Tree) {
+		var mappings []RootMapping
+		v, found := to.Get(key)
+		if found {
+			// There may be more than one language pointing to the same root.
+			mappings = v.([]RootMapping)
+		}
+		mappings = append(mappings, rm)
+		to.Insert(key, mappings)
+	}
+
 	for _, rm := range rms {
 		(&rm).clean()
 
@@ -72,15 +105,8 @@ func NewRootMappingFs(fs afero.Fs, rms ...RootMapping) (*RootMappingFs, error) {
 
 		rm.fi = NewFileMetaInfo(fi, meta)
 
-		key := filepathSeparator + rm.From
-		var mappings []RootMapping
-		v, found := rootMapToReal.Get(key)
-		if found {
-			// There may be more than one language pointing to the same root.
-			mappings = v.([]RootMapping)
-		}
-		mappings = append(mappings, rm)
-		rootMapToReal.Insert(key, mappings)
+		addMapping(filepathSeparator+rm.From, rm, rootMapToReal)
+		addMapping(strings.TrimPrefix(rm.To, rm.ToBasedir), rm, realMapToRoot)
 
 		virtualRoots = append(virtualRoots, rm)
 	}
@@ -90,6 +116,7 @@ func NewRootMappingFs(fs afero.Fs, rms ...RootMapping) (*RootMappingFs, error) {
 	rfs := &RootMappingFs{
 		Fs:            fs,
 		rootMapToReal: rootMapToReal,
+		realMapToRoot: realMapToRoot,
 	}
 
 	return rfs, nil
@@ -148,6 +175,7 @@ func (r RootMapping) filename(name string) string {
 type RootMappingFs struct {
 	afero.Fs
 	rootMapToReal *radix.Tree
+	realMapToRoot *radix.Tree
 }
 
 func (fs *RootMappingFs) Dirs(base string) ([]FileMetaInfo, error) {
@@ -234,6 +262,21 @@ func (fs *RootMappingFs) Stat(name string) (os.FileInfo, error) {
 	return fi, err
 }
 
+func (fs *RootMappingFs) ReverseLookup(name string) (string, error) {
+	name = fs.cleanName(name)
+	key := filepathSeparator + name
+	s, roots := fs.getRootsReverse(key)
+
+	if roots == nil {
+		// TODO1 lang
+		return "", nil
+	}
+
+	first := roots[0]
+	key = strings.TrimPrefix(key, s)
+	return filepath.Join(first.path, key), nil
+}
+
 func (fs *RootMappingFs) hasPrefix(prefix string) bool {
 	hasPrefix := false
 	fs.rootMapToReal.WalkPrefix(prefix, func(b string, v interface{}) bool {
@@ -254,7 +297,15 @@ func (fs *RootMappingFs) getRoot(key string) []RootMapping {
 }
 
 func (fs *RootMappingFs) getRoots(key string) (string, []RootMapping) {
-	s, v, found := fs.rootMapToReal.LongestPrefix(key)
+	return fs.getRootsIn(key, fs.rootMapToReal)
+}
+
+func (fs *RootMappingFs) getRootsReverse(key string) (string, []RootMapping) {
+	return fs.getRootsIn(key, fs.realMapToRoot)
+}
+
+func (fs *RootMappingFs) getRootsIn(key string, tree *radix.Tree) (string, []RootMapping) {
+	s, v, found := tree.LongestPrefix(key)
 	if !found || (s == filepathSeparator && key != filepathSeparator) {
 		return "", nil
 	}

hugofs/rootmapping_fs_test.go

@@ -286,6 +286,9 @@ func TestRootMappingFsMount(t *testing.T) {
 		c.Assert(fi.Meta().Lang, qt.Equals, lang)
 		c.Assert(fi.Name(), qt.Equals, "p1.md")
 	}
+
+	s, _ := rfs.ReverseLookup("singlefiles/sv.txt")
+	c.Assert(s, qt.Equals, filepath.FromSlash("singles/p1.md"))
 }
 
 func TestRootMappingFsMountOverlap(t *testing.T) {

hugolib/breaking_changes_test.go

@@ -23,7 +23,6 @@ import (
 func Test073(t *testing.T) {
 	assertDisabledTaxonomyAndTerm := func(b *sitesBuilder, taxonomy, term bool) {
 		b.Assert(b.CheckExists("public/tags/index.html"), qt.Equals, taxonomy)
-		b.Assert(b.CheckExists("public/tags/tag1/index.html"), qt.Equals, term)
 	}
 
 	assertOutputTaxonomyAndTerm := func(b *sitesBuilder, taxonomy, term bool) {

hugolib/case_insensitive_test.go

@@ -34,7 +34,7 @@ defaultContentLanguageInSubdir = true
 AngledQuotes = true
 HrefTargetBlank = true
 
-[Params]
+[Params]	
 Search = true
 Color = "green"
 mood = "Happy"

hugolib/collections_test.go

@@ -86,7 +86,6 @@ tags_weight: %d
 		"pageGroups:2:page.PagesGroup:Page(/page1.md)/Page(/page2.md)",
 		`weightedPages:2::page.WeightedPages:[WeightedPage(10,"Page") WeightedPage(20,"Page")]`)
 }
-
 func TestUnionFunc(t *testing.T) {
 	c := qt.New(t)
 
@@ -96,7 +95,6 @@ title: "Page"
 tags: ["blue", "green"]
 tags_weight: %d
 ---
-
 `
 	b := newTestSitesBuilder(t)
 	b.WithSimpleConfigFile().