hugolib: Implement "related content"

This closes #98, even if this commit does not do full content text search.

We may revisit that problem in the future, but that deserves its own issue.

Fixes #98

1 files changed, 276 insertions, 0 deletions

diff --git a/related/inverted_index_test.go b/related/inverted_index_test.go
new file mode 100644
index 000000000..781a969fb
--- /dev/null
+++ b/related/inverted_index_test.go
@@ -0,0 +1,276 @@
+// Copyright 2017-present 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 related
+
+import (
+	"fmt"
+	"math/rand"
+	"testing"
+	"time"
+
+	"github.com/stretchr/testify/require"
+)
+
+type testDoc struct {
+	keywords map[string][]Keyword
+	date     time.Time
+}
+
+func (k *testDoc) String() string {
+	s := "\n"
+	for k, v := range k.keywords {
+		s += k + ":\t\t"
+		for _, vv := range v {
+			s += "  " + vv.String()
+		}
+		s += "\n"
+	}
+	return s
+}
+
+func newTestDoc(name string, keywords ...string) *testDoc {
+	km := make(map[string][]Keyword)
+
+	time.Sleep(1 * time.Millisecond)
+	kw := &testDoc{keywords: km, date: time.Now()}
+
+	kw.addKeywords(name, keywords...)
+	return kw
+}
+
+func (t *testDoc) addKeywords(name string, keywords ...string) *testDoc {
+	keywordm := createTestKeywords(name, keywords...)
+
+	for k, v := range keywordm {
+		keywords := make([]Keyword, len(v))
+		for i := 0; i < len(v); i++ {
+			keywords[i] = StringKeyword(v[i])
+		}
+		t.keywords[k] = keywords
+	}
+	return t
+}
+
+func createTestKeywords(name string, keywords ...string) map[string][]string {
+	return map[string][]string{
+		name: keywords,
+	}
+}
+
+func (k *testDoc) SearchKeywords(cfg IndexConfig) ([]Keyword, error) {
+	return k.keywords[cfg.Name], nil
+}
+
+func (k *testDoc) PubDate() time.Time {
+	return k.date
+}
+
+func TestSearch(t *testing.T) {
+
+	config := Config{
+		Threshold:    90,
+		IncludeNewer: false,
+		Indices: IndexConfigs{
+			IndexConfig{Name: "tags", Weight: 50},
+			IndexConfig{Name: "keywords", Weight: 65},
+		},
+	}
+
+	idx := NewInvertedIndex(config)
+	//idx.debug = true
+
+	docs := []Document{
+		newTestDoc("tags", "a", "b", "c", "d"),
+		newTestDoc("tags", "b", "d", "g"),
+		newTestDoc("tags", "b", "h").addKeywords("keywords", "a"),
+		newTestDoc("tags", "g", "h").addKeywords("keywords", "a", "b"),
+	}
+
+	idx.Add(docs...)
+
+	t.Run("count", func(t *testing.T) {
+		assert := require.New(t)
+		assert.Len(idx.index, 2)
+		set1, found := idx.index["tags"]
+		assert.True(found)
+		// 6 tags
+		assert.Len(set1, 6)
+
+		set2, found := idx.index["keywords"]
+		assert.True(found)
+		assert.Len(set2, 2)
+
+	})
+
+	t.Run("search-tags", func(t *testing.T) {
+		assert := require.New(t)
+		m, err := idx.search(newQueryElement("tags", StringsToKeywords("a", "b", "d", "z")...))
+		assert.NoError(err)
+		assert.Len(m, 2)
+		assert.Equal(docs[0], m[0])
+		assert.Equal(docs[1], m[1])
+	})
+
+	t.Run("search-tags-and-keywords", func(t *testing.T) {
+		assert := require.New(t)
+		m, err := idx.search(
+			newQueryElement("tags", StringsToKeywords("a", "b", "z")...),
+			newQueryElement("keywords", StringsToKeywords("a", "b")...))
+		assert.NoError(err)
+		assert.Len(m, 3)
+		assert.Equal(docs[3], m[0])
+		assert.Equal(docs[2], m[1])
+		assert.Equal(docs[0], m[2])
+	})
+
+	t.Run("searchdoc-all", func(t *testing.T) {
+		assert := require.New(t)
+		doc := newTestDoc("tags", "a").addKeywords("keywords", "a")
+		m, err := idx.SearchDoc(doc)
+		assert.NoError(err)
+		assert.Len(m, 2)
+		assert.Equal(docs[3], m[0])
+		assert.Equal(docs[2], m[1])
+	})
+
+	t.Run("searchdoc-tags", func(t *testing.T) {
+		assert := require.New(t)
+		doc := newTestDoc("tags", "a", "b", "d", "z").addKeywords("keywords", "a", "b")
+		m, err := idx.SearchDoc(doc, "tags")
+		assert.NoError(err)
+		assert.Len(m, 2)
+		assert.Equal(docs[0], m[0])
+		assert.Equal(docs[1], m[1])
+	})
+
+	t.Run("searchdoc-keywords-date", func(t *testing.T) {
+		assert := require.New(t)
+		doc := newTestDoc("tags", "a", "b", "d", "z").addKeywords("keywords", "a", "b")
+		// This will get a date newer than the others.
+		newDoc := newTestDoc("keywords", "a", "b")
+		idx.Add(newDoc)
+
+		m, err := idx.SearchDoc(doc, "keywords")
+		assert.NoError(err)
+		assert.Len(m, 2)
+		assert.Equal(docs[3], m[0])
+	})
+
+}
+
+func BenchmarkRelatedNewIndex(b *testing.B) {
+
+	pages := make([]*testDoc, 100)
+	numkeywords := 30
+	allKeywords := make([]string, numkeywords)
+	for i := 0; i < numkeywords; i++ {
+		allKeywords[i] = fmt.Sprintf("keyword%d", i+1)
+	}
+
+	for i := 0; i < len(pages); i++ {
+		start := rand.Intn(len(allKeywords))
+		end := start + 3
+		if end >= len(allKeywords) {
+			end = start + 1
+		}
+
+		kw := newTestDoc("tags", allKeywords[start:end]...)
+		if i%5 == 0 {
+			start := rand.Intn(len(allKeywords))
+			end := start + 3
+			if end >= len(allKeywords) {
+				end = start + 1
+			}
+			kw.addKeywords("keywords", allKeywords[start:end]...)
+		}
+
+		pages[i] = kw
+	}
+
+	cfg := Config{
+		Threshold: 50,
+		Indices: IndexConfigs{
+			IndexConfig{Name: "tags", Weight: 100},
+			IndexConfig{Name: "keywords", Weight: 200},
+		},
+	}
+
+	b.Run("singles", func(b *testing.B) {
+		for i := 0; i < b.N; i++ {
+			idx := NewInvertedIndex(cfg)
+			for _, doc := range pages {
+				idx.Add(doc)
+			}
+		}
+	})
+
+	b.Run("all", func(b *testing.B) {
+		for i := 0; i < b.N; i++ {
+			idx := NewInvertedIndex(cfg)
+			docs := make([]Document, len(pages))
+			for i := 0; i < len(pages); i++ {
+				docs[i] = pages[i]
+			}
+			idx.Add(docs...)
+		}
+	})
+
+}
+
+func BenchmarkRelatedMatchesIn(b *testing.B) {
+
+	q1 := newQueryElement("tags", StringsToKeywords("keyword2", "keyword5", "keyword32", "asdf")...)
+	q2 := newQueryElement("keywords", StringsToKeywords("keyword3", "keyword4")...)
+
+	docs := make([]*testDoc, 1000)
+	numkeywords := 20
+	allKeywords := make([]string, numkeywords)
+	for i := 0; i < numkeywords; i++ {
+		allKeywords[i] = fmt.Sprintf("keyword%d", i+1)
+	}
+
+	cfg := Config{
+		Threshold: 20,
+		Indices: IndexConfigs{
+			IndexConfig{Name: "tags", Weight: 100},
+			IndexConfig{Name: "keywords", Weight: 200},
+		},
+	}
+
+	idx := NewInvertedIndex(cfg)
+
+	for i := 0; i < len(docs); i++ {
+		start := rand.Intn(len(allKeywords))
+		end := start + 3
+		if end >= len(allKeywords) {
+			end = start + 1
+		}
+
+		index := "tags"
+		if i%5 == 0 {
+			index = "keywords"
+		}
+
+		idx.Add(newTestDoc(index, allKeywords[start:end]...))
+	}
+
+	b.ResetTimer()
+	for i := 0; i < b.N; i++ {
+		if i%10 == 0 {
+			idx.search(q2)
+		} else {
+			idx.search(q1)
+		}
+	}
+}