Adding Prev/Next functionality to all lists of pages (sections, taxonomies, etc)

hugolib/pagesPrevNext.go

@@ -0,0 +1,38 @@
+// Copyright © 2014 Steve Francia <spf@spf13.com>.
+//
+// Licensed under the Simple Public 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://opensource.org/licenses/Simple-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
+
+func (p Pages) Prev(cur *Page) *Page {
+	for x, c := range p {
+		if c.UniqueId() == cur.UniqueId() {
+			if x == 0 {
+				return p[len(p)-1]
+			}
+			return p[x-1]
+		}
+	}
+	return nil
+}
+
+func (p Pages) Next(cur *Page) *Page {
+	for x, c := range p {
+		if c.UniqueId() == cur.UniqueId() {
+			if x < len(p)-1 {
+				return p[x+1]
+			}
+			return p[0]
+		}
+	}
+	return nil
+}

hugolib/pagesPrevNext_test.go

@@ -0,0 +1,96 @@
+// Copyright © 2014 Steve Francia <spf@spf13.com>.
+//
+// Licensed under the Simple Public 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://opensource.org/licenses/Simple-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 (
+	"testing"
+
+	"github.com/spf13/cast"
+	"github.com/stretchr/testify/assert"
+)
+
+type pagePNTestObject struct {
+	path   string
+	weight int
+	date   string
+}
+
+var pagePNTestSources = []pagePNTestObject{
+	{"/section1/testpage1.md", 5, "2012-04-06"},
+	{"/section1/testpage2.md", 4, "2012-01-01"},
+	{"/section1/testpage3.md", 3, "2012-04-06"},
+	{"/section2/testpage4.md", 2, "2012-03-02"},
+	{"/section2/testpage5.md", 1, "2012-04-06"},
+}
+
+func preparePagePNTestPages(t *testing.T) Pages {
+	var pages Pages
+	for _, s := range pagePNTestSources {
+		p, err := NewPage(s.path)
+		if err != nil {
+			t.Fatalf("failed to prepare test page %s", s.path)
+		}
+		p.Weight = s.weight
+		p.Date = cast.ToTime(s.date)
+		p.PublishDate = cast.ToTime(s.date)
+		pages = append(pages, p)
+	}
+	return pages
+}
+
+func TestPrev(t *testing.T) {
+	pages := preparePageGroupTestPages(t)
+	assert.Equal(t, pages.Prev(pages[0]), pages[4])
+	assert.Equal(t, pages.Prev(pages[1]), pages[0])
+	assert.Equal(t, pages.Prev(pages[4]), pages[3])
+}
+
+func TestNext(t *testing.T) {
+	pages := preparePageGroupTestPages(t)
+	assert.Equal(t, pages.Next(pages[0]), pages[1])
+	assert.Equal(t, pages.Next(pages[1]), pages[2])
+	assert.Equal(t, pages.Next(pages[4]), pages[0])
+}
+
+func prepareWeightedPagesPrevNext(t *testing.T) WeightedPages {
+	w := WeightedPages{}
+
+	for _, s := range pagePNTestSources {
+		p, err := NewPage(s.path)
+		if err != nil {
+			t.Fatalf("failed to prepare test page %s", s.path)
+		}
+		p.Weight = s.weight
+		p.Date = cast.ToTime(s.date)
+		p.PublishDate = cast.ToTime(s.date)
+		w = append(w, WeightedPage{p.Weight, p})
+	}
+
+	w.Sort()
+	return w
+}
+
+func TestWeightedPagesPrev(t *testing.T) {
+	w := prepareWeightedPagesPrevNext(t)
+	assert.Equal(t, w.Prev(w[0].Page), w[4].Page)
+	assert.Equal(t, w.Prev(w[1].Page), w[0].Page)
+	assert.Equal(t, w.Prev(w[4].Page), w[3].Page)
+}
+
+func TestWeightedPagesNext(t *testing.T) {
+	w := prepareWeightedPagesPrevNext(t)
+	assert.Equal(t, w.Next(w[0].Page), w[1].Page)
+	assert.Equal(t, w.Next(w[1].Page), w[2].Page)
+	assert.Equal(t, w.Next(w[4].Page), w[0].Page)
+}

hugolib/taxonomy.go

@@ -160,6 +160,30 @@ func (wp WeightedPages) Pages() Pages {
 	return pages
 }
 
+func (wp WeightedPages) Prev(cur *Page) *Page {
+	for x, c := range wp {
+		if c.Page.UniqueId() == cur.UniqueId() {
+			if x == 0 {
+				return wp[len(wp)-1].Page
+			}
+			return wp[x-1].Page
+		}
+	}
+	return nil
+}
+
+func (wp WeightedPages) Next(cur *Page) *Page {
+	for x, c := range wp {
+		if c.Page.UniqueId() == cur.UniqueId() {
+			if x < len(wp)-1 {
+				return wp[x+1].Page
+			}
+			return wp[0].Page
+		}
+	}
+	return nil
+}
+
 func (p WeightedPages) Len() int      { return len(p) }
 func (p WeightedPages) Swap(i, j int) { p[i], p[j] = p[j], p[i] }
 func (p WeightedPages) Sort()         { sort.Stable(p) }