Misc doc, code refactoring to improve documentation

12 files changed, 253 insertions, 24 deletions

diff --git a/resources/docs.go b/resources/docs.go
new file mode 100644
index 000000000..f992893da
--- /dev/null
+++ b/resources/docs.go
@@ -0,0 +1,15 @@
+// Copyright 2023 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 resources contains Resource related types.
+package resources
diff --git a/resources/images/exif/exif.go b/resources/images/exif/exif.go
index 487f250d5..8df348b23 100644
--- a/resources/images/exif/exif.go
+++ b/resources/images/exif/exif.go
@@ -254,8 +254,10 @@ func init() {
 	}
 }
 
+// Tags is a map of EXIF tags.
 type Tags map[string]any
 
+// UnmarshalJSON is for internal use only.
 func (v *Tags) UnmarshalJSON(b []byte) error {
 	vv := make(map[string]any)
 	if err := tcodec.Unmarshal(b, &vv); err != nil {
@@ -267,6 +269,7 @@ func (v *Tags) UnmarshalJSON(b []byte) error {
 	return nil
 }
 
+// MarshalJSON is for internal use only.
 func (v Tags) MarshalJSON() ([]byte, error) {
 	return tcodec.Marshal(v)
 }
diff --git a/resources/images/image_resource.go b/resources/images/image_resource.go
index 4e66b010c..846959006 100644
--- a/resources/images/image_resource.go
+++ b/resources/images/image_resource.go
@@ -29,6 +29,7 @@ type ImageResource interface {
 type ImageResourceOps interface {
 	// Height returns the height of the Image.
 	Height() int
+
 	// Width returns the width of the Image.
 	Width() int
 
@@ -37,8 +38,17 @@ type ImageResourceOps interface {
 	// Use the anchor option to change the crop box anchor point.
 	//    {{ $image := $image.Crop "600x400" }}
 	Crop(spec string) (ImageResource, error)
+
+	// Fill scales the image to the smallest possible size that will cover the specified dimensions in spec,
+	// crops the resized image to the specified dimensions using the given anchor point.
+	// The spec is space delimited, e.g. `200x300 TopLeft`.
 	Fill(spec string) (ImageResource, error)
+
+	// Fit scales down the image using the given spec.
 	Fit(spec string) (ImageResource, error)
+
+	// Resize resizes the image to the given spec. If one of width or height is 0, the image aspect
+	// ratio is preserved.
 	Resize(spec string) (ImageResource, error)
 
 	// Filter applies one or more filters to an Image.
diff --git a/resources/page/page.go b/resources/page/page.go
index 929f04d93..eeb2cdb28 100644
--- a/resources/page/page.go
+++ b/resources/page/page.go
@@ -21,7 +21,6 @@ import (
 	"github.com/gohugoio/hugo/identity"
 	"github.com/gohugoio/hugo/markup/converter"
 
-	"github.com/bep/gitmap"
 	"github.com/gohugoio/hugo/config"
 	"github.com/gohugoio/hugo/tpl"
 
@@ -61,18 +60,17 @@ type AuthorProvider interface {
 
 // ChildCareProvider provides accessors to child resources.
 type ChildCareProvider interface {
+	// Pages returns a list of pages of all kinds.
 	Pages() Pages
 
 	// RegularPages returns a list of pages of kind 'Page'.
-	// In Hugo 0.57 we changed the Pages method so it returns all page
-	// kinds, even sections. If you want the old behaviour, you can
-	// use RegularPages.
 	RegularPages() Pages
 
 	// RegularPagesRecursive returns all regular pages below the current
 	// section.
 	RegularPagesRecursive() Pages
 
+	// Resources returns a list of all resources.
 	Resources() resource.Resources
 }
 
@@ -103,16 +101,21 @@ type ContentProvider interface {
 	ReadingTime() int
 
 	// Len returns the length of the content.
+	// This is for internal use only.
 	Len() int
 }
 
 // ContentRenderer provides the content rendering methods for some content.
 type ContentRenderer interface {
+	// RenderContent renders the given content.
+	// For internal use only.
 	RenderContent(content []byte, renderTOC bool) (converter.Result, error)
 }
 
 // FileProvider provides the source file.
 type FileProvider interface {
+	// File returns the source file for this Page,
+	// or a zero File if this Page is not backed by a file.
 	File() source.File
 }
 
@@ -131,13 +134,17 @@ type GetPageProvider interface {
 
 // GitInfoProvider provides Git info.
 type GitInfoProvider interface {
-	GitInfo() *gitmap.GitInfo
+	// GitInfo returns the Git info for this object.
+	GitInfo() source.GitInfo
+	// CodeOwners returns the code owners for this object.
 	CodeOwners() []string
 }
 
 // InSectionPositioner provides section navigation.
 type InSectionPositioner interface {
+	// NextInSection returns the next page in the same section.
 	NextInSection() Page
+	// PrevInSection returns the previous page in the same section.
 	PrevInSection() Page
 }
 
@@ -149,6 +156,7 @@ type InternalDependencies interface {
 
 // OutputFormatsProvider provides the OutputFormats of a Page.
 type OutputFormatsProvider interface {
+	// OutputFormats returns the OutputFormats for this Page.
 	OutputFormats() OutputFormats
 }
 
@@ -229,6 +237,7 @@ type PageMetaProvider interface {
 	SectionsPath() string
 
 	// Sitemap returns the sitemap configuration for this page.
+	// This is for internal use only.
 	Sitemap() config.Sitemap
 
 	// Type is a discriminator used to select layouts etc. It is typically set
@@ -242,7 +251,15 @@ type PageMetaProvider interface {
 
 // PageRenderProvider provides a way for a Page to render content.
 type PageRenderProvider interface {
+	// Render renders the given layout with this Page as context.
 	Render(layout ...string) (template.HTML, error)
+	// RenderString renders the first value in args with tPaginatorhe content renderer defined
+	// for this Page.
+	// It takes an optional map as a second argument:
+	//
+	// display (“inline”):
+	// - inline or block. If inline (default), surrounding <p></p> on short snippets will be trimmed.
+	// markup (defaults to the Page’s markup)
 	RenderString(args ...any) (template.HTML, error)
 }
 
@@ -311,7 +328,9 @@ type PageWithoutContent interface {
 
 // Positioner provides next/prev navigation.
 type Positioner interface {
+	// Next points up to the next regular page (sorted by Hugo’s default sort).
 	Next() Page
+	// Prev points down to the previous regular page (sorted by Hugo’s default sort).
 	Prev() Page
 
 	// Deprecated: Use Prev. Will be removed in Hugo 0.57
@@ -323,16 +342,19 @@ type Positioner interface {
 
 // RawContentProvider provides the raw, unprocessed content of the page.
 type RawContentProvider interface {
+	// RawContent returns the raw, unprocessed content of the page excluding any front matter.
 	RawContent() string
 }
 
 // RefProvider provides the methods needed to create reflinks to pages.
 type RefProvider interface {
+	// Ref returns an absolute URl to a page.
 	Ref(argsm map[string]any) (string, error)
 
 	// RefFrom is for internal use only.
 	RefFrom(argsm map[string]any, source any) (string, error)
 
+	// RelRef returns a relative URL to a page.
 	RelRef(argsm map[string]any) (string, error)
 
 	// RefFrom is for internal use only.
@@ -356,12 +378,15 @@ type ShortcodeInfoProvider interface {
 
 // SitesProvider provide accessors to get sites.
 type SitesProvider interface {
+	// Site returns the current site.
 	Site() Site
+	// Sites returns all sites.
 	Sites() Sites
 }
 
 // TableOfContentsProvider provides the table of contents for a Page.
 type TableOfContentsProvider interface {
+	// TableOfContents returns the table of contents for the page rendered as HTML.
 	TableOfContents() template.HTML
 }
 
@@ -382,7 +407,7 @@ type TranslationsProvider interface {
 // TreeProvider provides section tree navigation.
 type TreeProvider interface {
 
-	// IsAncestor returns whether the current page is an ancestor of the given
+	// IsAncestor returns whether the current page is an ancestor of other.
 	// Note that this method is not relevant for taxonomy lists and taxonomy terms pages.
 	IsAncestor(other any) (bool, error)
 
@@ -390,7 +415,7 @@ type TreeProvider interface {
 	// Note that this will return nil for pages that is not regular, home or section pages.
 	CurrentSection() Page
 
-	// IsDescendant returns whether the current page is a descendant of the given
+	// IsDescendant returns whether the current page is a descendant of other.
 	// Note that this method is not relevant for taxonomy lists and taxonomy terms pages.
 	IsDescendant(other any) (bool, error)
 
@@ -398,7 +423,7 @@ type TreeProvider interface {
 	// For the home page, this will return itself.
 	FirstSection() Page
 
-	// InSection returns whether the given page is in the current section.
+	// InSection returns whether other is in the current section.
 	// Note that this will always return false for pages that are
 	// not either regular, home or section pages.
 	InSection(other any) (bool, error)
diff --git a/resources/page/page_marshaljson.autogen.go b/resources/page/page_marshaljson.autogen.go
index 0f73d81ae..373257878 100644
--- a/resources/page/page_marshaljson.autogen.go
+++ b/resources/page/page_marshaljson.autogen.go
@@ -17,7 +17,6 @@ package page
 
 import (
 	"encoding/json"
-	"github.com/bep/gitmap"
 	"github.com/gohugoio/hugo/common/maps"
 	"github.com/gohugoio/hugo/config"
 	"github.com/gohugoio/hugo/hugofs/files"
@@ -82,6 +81,7 @@ func MarshalPageToJSON(p Page) ([]byte, error) {
 	language := p.Language()
 	file := p.File()
 	gitInfo := p.GitInfo()
+	codeOwners := p.CodeOwners()
 	outputFormats := p.OutputFormats()
 	alternativeOutputFormats := p.AlternativeOutputFormats()
 	menus := p.Menus()
@@ -89,10 +89,11 @@ func MarshalPageToJSON(p Page) ([]byte, error) {
 	isTranslated := p.IsTranslated()
 	allTranslations := p.AllTranslations()
 	translations := p.Translations()
+	store := p.Store()
 	getIdentity := p.GetIdentity()
 
 	s := struct {
-		Content                  any
+		Content                  interface{}
 		Plain                    string
 		PlainWords               []string
 		Summary                  template.HTML
@@ -110,7 +111,7 @@ func MarshalPageToJSON(p Page) ([]byte, error) {
 		Name                     string
 		Title                    string
 		Params                   maps.Params
-		Data                     any
+		Data                     interface{}
 		Date                     time.Time
 		Lastmod                  time.Time
 		PublishDate              time.Time
@@ -139,7 +140,8 @@ func MarshalPageToJSON(p Page) ([]byte, error) {
 		Weight                   int
 		Language                 *langs.Language
 		File                     source.File
-		GitInfo                  *gitmap.GitInfo
+		GitInfo                  source.GitInfo
+		CodeOwners               []string
 		OutputFormats            OutputFormats
 		AlternativeOutputFormats OutputFormats
 		Menus                    navigation.PageMenus
@@ -147,6 +149,7 @@ func MarshalPageToJSON(p Page) ([]byte, error) {
 		IsTranslated             bool
 		AllTranslations          Pages
 		Translations             Pages
+		Store                    *maps.Scratch
 		GetIdentity              identity.Identity
 	}{
 		Content:                  content,
@@ -197,6 +200,7 @@ func MarshalPageToJSON(p Page) ([]byte, error) {
 		Language:                 language,
 		File:                     file,
 		GitInfo:                  gitInfo,
+		CodeOwners:               codeOwners,
 		OutputFormats:            outputFormats,
 		AlternativeOutputFormats: alternativeOutputFormats,
 		Menus:                    menus,
@@ -204,6 +208,7 @@ func MarshalPageToJSON(p Page) ([]byte, error) {
 		IsTranslated:             isTranslated,
 		AllTranslations:          allTranslations,
 		Translations:             translations,
+		Store:                    store,
 		GetIdentity:              getIdentity,
 	}
 
diff --git a/resources/page/page_nop.go b/resources/page/page_nop.go
index 15f8c3950..c4af3f554 100644
--- a/resources/page/page_nop.go
+++ b/resources/page/page_nop.go
@@ -28,7 +28,6 @@ import (
 
 	"github.com/gohugoio/hugo/hugofs"
 
-	"github.com/bep/gitmap"
 	"github.com/gohugoio/hugo/navigation"
 
 	"github.com/gohugoio/hugo/common/hugo"
@@ -200,8 +199,8 @@ func (p *nopPage) GetTerms(taxonomy string) Pages {
 	return nil
 }
 
-func (p *nopPage) GitInfo() *gitmap.GitInfo {
-	return nil
+func (p *nopPage) GitInfo() source.GitInfo {
+	return source.GitInfo{}
 }
 
 func (p *nopPage) CodeOwners() []string {
diff --git a/resources/page/pagination.go b/resources/page/pagination.go
index 9f4bfcff5..46d9fda82 100644
--- a/resources/page/pagination.go
+++ b/resources/page/pagination.go
@@ -27,8 +27,10 @@ import (
 
 // PaginatorProvider provides two ways to create a page paginator.
 type PaginatorProvider interface {
+	// Paginator creates a paginator with the default page set.
 	Paginator(options ...any) (*Pager, error)
-	Paginate(seq any, options ...any) (*Pager, error)
+	// Paginate creates a paginator with the given page set in pages.
+	Paginate(pages any, options ...any) (*Pager, error)
 }
 
 // Pager represents one of the elements in a paginator.
diff --git a/resources/page/site.go b/resources/page/site.go
index f5806280c..8daff95ae 100644
--- a/resources/page/site.go
+++ b/resources/page/site.go
@@ -26,8 +26,7 @@ import (
 	"github.com/gohugoio/hugo/navigation"
 )
 
-// Site represents a site in the build. This is currently a very narrow interface,
-// but the actual implementation will be richer, see hugolib.SiteInfo.
+// Site represents a site. There can be multople sites in a multilingual setup.
 type Site interface {
 	// Returns the Language configured for this Site.
 	Language() *langs.Language
@@ -63,7 +62,7 @@ type Site interface {
 	BaseURL() template.URL
 
 	// Retuns a taxonomy map.
-	Taxonomies() any
+	Taxonomies() TaxonomyList
 
 	// Returns the last modification date of the content.
 	LastChange() time.Time
@@ -142,7 +141,7 @@ func (t testSite) Menus() navigation.Menus {
 	return nil
 }
 
-func (t testSite) Taxonomies() any {
+func (t testSite) Taxonomies() TaxonomyList {
 	return nil
 }
 
diff --git a/resources/page/taxonomy.go b/resources/page/taxonomy.go
new file mode 100644
index 000000000..f50152f90
--- /dev/null
+++ b/resources/page/taxonomy.go
@@ -0,0 +1,168 @@
+// Copyright 2023 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 page
+
+import (
+	"fmt"
+	"sort"
+
+	"github.com/gohugoio/hugo/compare"
+	"github.com/gohugoio/hugo/langs"
+)
+
+// The TaxonomyList is a list of all taxonomies and their values
+// e.g. List['tags'] => TagTaxonomy (from above)
+type TaxonomyList map[string]Taxonomy
+
+func (tl TaxonomyList) String() string {
+	return fmt.Sprintf("TaxonomyList(%d)", len(tl))
+}
+
+// A Taxonomy is a map of keywords to a list of pages.
+// For example
+//
+//	TagTaxonomy['technology'] = WeightedPages
+//	TagTaxonomy['go']  =  WeightedPages
+type Taxonomy map[string]WeightedPages
+
+// OrderedTaxonomy is another representation of an Taxonomy using an array rather than a map.
+// Important because you can't order a map.
+type OrderedTaxonomy []OrderedTaxonomyEntry
+
+// getOneOPage returns one page in the taxonomy,
+// nil if there is none.
+func (t OrderedTaxonomy) getOneOPage() Page {
+	if len(t) == 0 {
+		return nil
+	}
+	return t[0].Pages()[0]
+}
+
+// OrderedTaxonomyEntry is similar to an element of a Taxonomy, but with the key embedded (as name)
+// e.g:  {Name: Technology, WeightedPages: TaxonomyPages}
+type OrderedTaxonomyEntry struct {
+	Name string
+	WeightedPages
+}
+
+// Get the weighted pages for the given key.
+func (i Taxonomy) Get(key string) WeightedPages {
+	return i[key]
+}
+
+// Count the weighted pages for the given key.
+func (i Taxonomy) Count(key string) int { return len(i[key]) }
+
+// TaxonomyArray returns an ordered taxonomy with a non defined order.
+func (i Taxonomy) TaxonomyArray() OrderedTaxonomy {
+	ies := make([]OrderedTaxonomyEntry, len(i))
+	count := 0
+	for k, v := range i {
+		ies[count] = OrderedTaxonomyEntry{Name: k, WeightedPages: v}
+		count++
+	}
+	return ies
+}
+
+// Alphabetical returns an ordered taxonomy sorted by key name.
+func (i Taxonomy) Alphabetical() OrderedTaxonomy {
+	ia := i.TaxonomyArray()
+	p := ia.getOneOPage()
+	if p == nil {
+		return ia
+	}
+	currentSite := p.Site().Current()
+	coll := langs.GetCollator(currentSite.Language())
+	coll.Lock()
+	defer coll.Unlock()
+	name := func(i1, i2 *OrderedTaxonomyEntry) bool {
+		return coll.CompareStrings(i1.Name, i2.Name) < 0
+	}
+	oiBy(name).Sort(ia)
+	return ia
+}
+
+// ByCount returns an ordered taxonomy sorted by # of pages per key.
+// If taxonomies have the same # of pages, sort them alphabetical
+func (i Taxonomy) ByCount() OrderedTaxonomy {
+	count := func(i1, i2 *OrderedTaxonomyEntry) bool {
+		li1 := len(i1.WeightedPages)
+		li2 := len(i2.WeightedPages)
+
+		if li1 == li2 {
+			return compare.LessStrings(i1.Name, i2.Name)
+		}
+		return li1 > li2
+	}
+
+	ia := i.TaxonomyArray()
+	oiBy(count).Sort(ia)
+	return ia
+}
+
+// Pages returns the Pages for this taxonomy.
+func (ie OrderedTaxonomyEntry) Pages() Pages {
+	return ie.WeightedPages.Pages()
+}
+
+// Count returns the count the pages in this taxonomy.
+func (ie OrderedTaxonomyEntry) Count() int {
+	return len(ie.WeightedPages)
+}
+
+// Term returns the name given to this taxonomy.
+func (ie OrderedTaxonomyEntry) Term() string {
+	return ie.Name
+}
+
+// Reverse reverses the order of the entries in this taxonomy.
+func (t OrderedTaxonomy) Reverse() OrderedTaxonomy {
+	for i, j := 0, len(t)-1; i < j; i, j = i+1, j-1 {
+		t[i], t[j] = t[j], t[i]
+	}
+
+	return t
+}
+
+// A type to implement the sort interface for TaxonomyEntries.
+type orderedTaxonomySorter struct {
+	taxonomy OrderedTaxonomy
+	by       oiBy
+}
+
+// Closure used in the Sort.Less method.
+type oiBy func(i1, i2 *OrderedTaxonomyEntry) bool
+
+func (by oiBy) Sort(taxonomy OrderedTaxonomy) {
+	ps := &orderedTaxonomySorter{
+		taxonomy: taxonomy,
+		by:       by, // The Sort method's receiver is the function (closure) that defines the sort order.
+	}
+	sort.Stable(ps)
+}
+
+// Len is part of sort.Interface.
+func (s *orderedTaxonomySorter) Len() int {
+	return len(s.taxonomy)
+}
+
+// Swap is part of sort.Interface.
+func (s *orderedTaxonomySorter) Swap(i, j int) {
+	s.taxonomy[i], s.taxonomy[j] = s.taxonomy[j], s.taxonomy[i]
+}
+
+// Less is part of sort.Interface. It is implemented by calling the "by" closure in the sorter.
+func (s *orderedTaxonomySorter) Less(i, j int) bool {
+	return s.by(&s.taxonomy[i], &s.taxonomy[j])
+}
diff --git a/resources/page/testhelpers_test.go b/resources/page/testhelpers_test.go
index 22346c389..e8275ba40 100644
--- a/resources/page/testhelpers_test.go
+++ b/resources/page/testhelpers_test.go
@@ -26,7 +26,6 @@ import (
 
 	"github.com/gohugoio/hugo/modules"
 
-	"github.com/bep/gitmap"
 	"github.com/gohugoio/hugo/helpers"
 	"github.com/gohugoio/hugo/resources/resource"
 
@@ -250,8 +249,8 @@ func (p *testPage) GetRelatedDocsHandler() *RelatedDocsHandler {
 	return relatedDocsHandler
 }
 
-func (p *testPage) GitInfo() *gitmap.GitInfo {
-	return nil
+func (p *testPage) GitInfo() source.GitInfo {
+	return source.GitInfo{}
 }
 
 func (p *testPage) CodeOwners() []string {
diff --git a/resources/resource/resources.go b/resources/resource/resources.go
index a888d6fb4..a877c8906 100644
--- a/resources/resource/resources.go
+++ b/resources/resource/resources.go
@@ -1,4 +1,4 @@
-// Copyright 2019 The Hugo Authors. All rights reserved.
+// Copyright 2023 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.
@@ -11,6 +11,7 @@
 // See the License for the specific language governing permissions and
 // limitations under the License.
 
+// Package resource contains Resource related types.
 package resource
 
 import (
diff --git a/resources/resource/resourcetypes.go b/resources/resource/resourcetypes.go
index 4ba95c170..4ef5fc5a0 100644
--- a/resources/resource/resourcetypes.go
+++ b/resources/resource/resourcetypes.go
@@ -64,6 +64,9 @@ type ResourceError interface {
 
 // ErrProvider provides an Err.
 type ErrProvider interface {
+
+	// Err returns an error if this resource is in an error state.
+	// This will currently only be set for resources obtained from resources.GetRemote.
 	Err() ResourceError
 }