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

resources/page/permalinks_test.go

@@ -0,0 +1,180 @@
+// 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 page
+
+import (
+	"fmt"
+	"sync"
+	"testing"
+	"time"
+
+	"github.com/stretchr/testify/require"
+)
+
+// testdataPermalinks is used by a couple of tests; the expandsTo content is
+// subject to the data in simplePageJSON.
+var testdataPermalinks = []struct {
+	spec      string
+	valid     bool
+	expandsTo string
+}{
+	{":title", true, "spf13-vim-3.0-release-and-new-website"},
+	{"/:year-:month-:title", true, "/2012-04-spf13-vim-3.0-release-and-new-website"},
+	{"/:year/:yearday/:month/:monthname/:day/:weekday/:weekdayname/", true, "/2012/97/04/April/06/5/Friday/"}, // Dates
+	{"/:section/", true, "/blue/"},                                // Section
+	{"/:title/", true, "/spf13-vim-3.0-release-and-new-website/"}, // Title
+	{"/:slug/", true, "/the-slug/"},                               // Slug
+	{"/:filename/", true, "/test-page/"},                          // Filename
+	// TODO(moorereason): need test scaffolding for this.
+	//{"/:sections/", false, "/blue/"},                              // Sections
+
+	// Failures
+	{"/blog/:fred", false, ""},
+	{"/:year//:title", false, ""},
+}
+
+func TestPermalinkExpansion(t *testing.T) {
+	t.Parallel()
+
+	assert := require.New(t)
+
+	page := newTestPageWithFile("/test-page/index.md")
+	page.title = "Spf13 Vim 3.0 Release and new website"
+	d, _ := time.Parse("2006-01-02", "2012-04-06")
+	page.date = d
+	page.section = "blue"
+	page.slug = "The Slug"
+
+	for i, item := range testdataPermalinks {
+
+		msg := fmt.Sprintf("Test %d", i)
+
+		if !item.valid {
+			continue
+		}
+
+		permalinksConfig := map[string]string{
+			"posts": item.spec,
+		}
+
+		ps := newTestPathSpec()
+		ps.Cfg.Set("permalinks", permalinksConfig)
+
+		expander, err := NewPermalinkExpander(ps)
+		assert.NoError(err)
+
+		expanded, err := expander.Expand("posts", page)
+		assert.NoError(err)
+		assert.Equal(item.expandsTo, expanded, msg)
+
+	}
+}
+
+func TestPermalinkExpansionMultiSection(t *testing.T) {
+	t.Parallel()
+
+	assert := require.New(t)
+
+	page := newTestPage()
+	page.title = "Page Title"
+	d, _ := time.Parse("2006-01-02", "2012-04-06")
+	page.date = d
+	page.section = "blue"
+	page.slug = "The Slug"
+
+	permalinksConfig := map[string]string{
+		"posts": "/:slug",
+		"blog":  "/:section/:year",
+	}
+
+	ps := newTestPathSpec()
+	ps.Cfg.Set("permalinks", permalinksConfig)
+
+	expander, err := NewPermalinkExpander(ps)
+	assert.NoError(err)
+
+	expanded, err := expander.Expand("posts", page)
+	assert.NoError(err)
+	assert.Equal("/the-slug", expanded)
+
+	expanded, err = expander.Expand("blog", page)
+	assert.NoError(err)
+	assert.Equal("/blue/2012", expanded)
+
+}
+
+func TestPermalinkExpansionConcurrent(t *testing.T) {
+	t.Parallel()
+
+	assert := require.New(t)
+
+	permalinksConfig := map[string]string{
+		"posts": "/:slug/",
+	}
+
+	ps := newTestPathSpec()
+	ps.Cfg.Set("permalinks", permalinksConfig)
+
+	expander, err := NewPermalinkExpander(ps)
+	assert.NoError(err)
+
+	var wg sync.WaitGroup
+
+	for i := 1; i < 20; i++ {
+		wg.Add(1)
+		go func(i int) {
+			defer wg.Done()
+			page := newTestPage()
+			for j := 1; j < 20; j++ {
+				page.slug = fmt.Sprintf("slug%d", i+j)
+				expanded, err := expander.Expand("posts", page)
+				assert.NoError(err)
+				assert.Equal(fmt.Sprintf("/%s/", page.slug), expanded)
+			}
+		}(i)
+	}
+
+	wg.Wait()
+}
+
+func BenchmarkPermalinkExpand(b *testing.B) {
+	page := newTestPage()
+	page.title = "Hugo Rocks"
+	d, _ := time.Parse("2006-01-02", "2019-02-28")
+	page.date = d
+
+	permalinksConfig := map[string]string{
+		"posts": "/:year-:month-:title",
+	}
+
+	ps := newTestPathSpec()
+	ps.Cfg.Set("permalinks", permalinksConfig)
+
+	expander, err := NewPermalinkExpander(ps)
+	if err != nil {
+		b.Fatal(err)
+	}
+
+	b.ResetTimer()
+	for i := 0; i < b.N; i++ {
+		s, err := expander.Expand("posts", page)
+		if err != nil {
+			b.Fatal(err)
+		}
+		if s != "/2019-02-hugo-rocks" {
+			b.Fatal(s)
+		}
+
+	}
+}