Make Page an interface

The main motivation of this commit is to add a `page.Page` interface to replace the very file-oriented `hugolib.Page` struct.
This is all a preparation step for issue  #5074, "pages from other data sources".

But this also fixes a set of annoying limitations, especially related to custom output formats, and shortcodes.

Most notable changes:

* The inner content of shortcodes using the `{{%` as the outer-most delimiter will now be sent to the content renderer, e.g. Blackfriday.
  This means that any markdown will partake in the global ToC and footnote context etc.
* The Custom Output formats are now "fully virtualized". This removes many of the current limitations.
* The taxonomy list type now has a reference to the `Page` object.
  This improves the taxonomy template `.Title` situation and make common template constructs much simpler.

See #5074
Fixes #5763
Fixes #5758
Fixes #5090
Fixes #5204
Fixes #4695
Fixes #5607
Fixes #5707
Fixes #5719
Fixes #3113
Fixes #5706
Fixes #5767
Fixes #5723
Fixes #5769
Fixes #5770
Fixes #5771
Fixes #5759
Fixes #5776
Fixes #5777
Fixes #5778

1 files changed, 20 insertions, 22 deletions

diff --git a/hugolib/site_output_test.go b/hugolib/site_output_test.go
index e9a7e113e..e4947e5cd 100644
--- a/hugolib/site_output_test.go
+++ b/hugolib/site_output_test.go
@@ -1,4 +1,4 @@
-// Copyright 2017-present The Hugo Authors. All rights reserved.
+// 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.
@@ -17,6 +17,8 @@ import (
 	"strings"
 	"testing"
 
+	"github.com/gohugoio/hugo/resources/page"
+
 	"github.com/spf13/afero"
 
 	"github.com/stretchr/testify/require"
@@ -148,15 +150,15 @@ Len Pages: {{ .Kind }} {{ len .Site.RegularPages }} Page Number: {{ .Paginator.P
 	require.NoError(t, err)
 
 	s := h.Sites[0]
-	require.Equal(t, "en", s.Language.Lang)
+	require.Equal(t, "en", s.language.Lang)
 
-	home := s.getPage(KindHome)
+	home := s.getPage(page.KindHome)
 
 	require.NotNil(t, home)
 
 	lenOut := len(outputs)
 
-	require.Len(t, home.outputFormats, lenOut)
+	require.Len(t, home.OutputFormats(), lenOut)
 
 	// There is currently always a JSON output to make it simpler ...
 	altFormats := lenOut - 1
@@ -207,12 +209,8 @@ Len Pages: {{ .Kind }} {{ len .Site.RegularPages }} Page Number: {{ .Paginator.P
 	}
 
 	of := home.OutputFormats()
-	require.Len(t, of, lenOut)
-	require.Nil(t, of.Get("Hugo"))
-	require.NotNil(t, of.Get("json"))
+
 	json := of.Get("JSON")
-	_, err = home.AlternativeOutputFormats()
-	require.Error(t, err)
 	require.NotNil(t, json)
 	require.Equal(t, "/blog/index.json", json.RelPermalink())
 	require.Equal(t, "http://example.com/blog/index.json", json.Permalink())
@@ -323,7 +321,7 @@ baseName = "customdelimbase"
 	th.assertFileContent("public/customdelimbase_del", "custom delim")
 
 	s := h.Sites[0]
-	home := s.getPage(KindHome)
+	home := s.getPage(page.KindHome)
 	require.NotNil(t, home)
 
 	outputs := home.OutputFormats()
@@ -339,8 +337,8 @@ func TestCreateSiteOutputFormats(t *testing.T) {
 	assert := require.New(t)
 
 	outputsConfig := map[string]interface{}{
-		KindHome:    []string{"HTML", "JSON"},
-		KindSection: []string{"JSON"},
+		page.KindHome:    []string{"HTML", "JSON"},
+		page.KindSection: []string{"JSON"},
 	}
 
 	cfg := viper.New()
@@ -348,13 +346,13 @@ func TestCreateSiteOutputFormats(t *testing.T) {
 
 	outputs, err := createSiteOutputFormats(output.DefaultFormats, cfg)
 	assert.NoError(err)
-	assert.Equal(output.Formats{output.JSONFormat}, outputs[KindSection])
-	assert.Equal(output.Formats{output.HTMLFormat, output.JSONFormat}, outputs[KindHome])
+	assert.Equal(output.Formats{output.JSONFormat}, outputs[page.KindSection])
+	assert.Equal(output.Formats{output.HTMLFormat, output.JSONFormat}, outputs[page.KindHome])
 
 	// Defaults
-	assert.Equal(output.Formats{output.HTMLFormat, output.RSSFormat}, outputs[KindTaxonomy])
-	assert.Equal(output.Formats{output.HTMLFormat, output.RSSFormat}, outputs[KindTaxonomyTerm])
-	assert.Equal(output.Formats{output.HTMLFormat}, outputs[KindPage])
+	assert.Equal(output.Formats{output.HTMLFormat, output.RSSFormat}, outputs[page.KindTaxonomy])
+	assert.Equal(output.Formats{output.HTMLFormat, output.RSSFormat}, outputs[page.KindTaxonomyTerm])
+	assert.Equal(output.Formats{output.HTMLFormat}, outputs[page.KindPage])
 
 	// These aren't (currently) in use when rendering in Hugo,
 	// but the pages needs to be assigned an output format,
@@ -370,7 +368,7 @@ func TestCreateSiteOutputFormatsInvalidConfig(t *testing.T) {
 	assert := require.New(t)
 
 	outputsConfig := map[string]interface{}{
-		KindHome: []string{"FOO", "JSON"},
+		page.KindHome: []string{"FOO", "JSON"},
 	}
 
 	cfg := viper.New()
@@ -384,7 +382,7 @@ func TestCreateSiteOutputFormatsEmptyConfig(t *testing.T) {
 	assert := require.New(t)
 
 	outputsConfig := map[string]interface{}{
-		KindHome: []string{},
+		page.KindHome: []string{},
 	}
 
 	cfg := viper.New()
@@ -392,14 +390,14 @@ func TestCreateSiteOutputFormatsEmptyConfig(t *testing.T) {
 
 	outputs, err := createSiteOutputFormats(output.DefaultFormats, cfg)
 	assert.NoError(err)
-	assert.Equal(output.Formats{output.HTMLFormat, output.RSSFormat}, outputs[KindHome])
+	assert.Equal(output.Formats{output.HTMLFormat, output.RSSFormat}, outputs[page.KindHome])
 }
 
 func TestCreateSiteOutputFormatsCustomFormats(t *testing.T) {
 	assert := require.New(t)
 
 	outputsConfig := map[string]interface{}{
-		KindHome: []string{},
+		page.KindHome: []string{},
 	}
 
 	cfg := viper.New()
@@ -412,5 +410,5 @@ func TestCreateSiteOutputFormatsCustomFormats(t *testing.T) {
 
 	outputs, err := createSiteOutputFormats(output.Formats{customRSS, customHTML}, cfg)
 	assert.NoError(err)
-	assert.Equal(output.Formats{customHTML, customRSS}, outputs[KindHome])
+	assert.Equal(output.Formats{customHTML, customRSS}, outputs[page.KindHome])
 }