Data structures for tag manipulation

Makefile

@@ -38,6 +38,13 @@ build: $(binary_name)
 $(binary_name): $(wildcard **/*.go)
 	go build
 
+.PHONY: protobuf
+protobuf: tag/internal/bilocation.pb.go
+
+tag/internal/bilocation.pb.go: bilocation.proto
+	mkdir -p $(@D)
+	protoc --go_out=$(@D) $<
+
 .PHONY: clean
 clean:
 	rm -rf $(binary_name) $(cover_file)

bilocation.proto

@@ -0,0 +1,12 @@
+syntax = "proto3";
+
+package internal;
+
+message Set {
+  repeated Tag tags = 1;
+}
+
+message Tag {
+  string name = 1;
+  repeated string classifiers = 2;
+}

go.mod

@@ -6,7 +6,9 @@ require (
 	github.com/bketelsen/logr v0.0.0-20170116012416-f3d070bdd1c5
 	github.com/corvus-ch/logr v0.0.0-20180917163152-45217966b77e
 	github.com/davecgh/go-spew v1.1.1 // indirect
+	github.com/golang/protobuf v1.2.0
 	github.com/sebdah/goldie v0.0.0-20180424091453-8784dd1ab561
 	github.com/stretchr/testify v1.3.0
+	golang.org/x/sync v0.0.0-20181221193216-37e7f081c4d4 // indirect
 	gopkg.in/alecthomas/kingpin.v2 v2.2.6
 )

go.sum

@@ -10,12 +10,16 @@ github.com/davecgh/go-spew v1.1.0 h1:ZDRjVQ15GmhC3fiQ8ni8+OwkZQO4DARzQgrnXU1Liz8
 github.com/davecgh/go-spew v1.1.0/go.mod h1:J7Y8YcW2NihsgmVo/mv3lAwl/skON4iLHjSsI+c5H38=
 github.com/davecgh/go-spew v1.1.1 h1:vj9j/u1bqnvCEfJOwUhtlOARqs3+rkHYY13jYWTU97c=
 github.com/davecgh/go-spew v1.1.1/go.mod h1:J7Y8YcW2NihsgmVo/mv3lAwl/skON4iLHjSsI+c5H38=
+github.com/golang/protobuf v1.2.0 h1:P3YflyNX/ehuJFLhxviNdFxQPkGK5cDcApsge1SqnvM=
+github.com/golang/protobuf v1.2.0/go.mod h1:6lQm79b+lXiMfvg/cZm0SGofjICqVBUtrP5yJMmIC1U=
 github.com/pmezard/go-difflib v1.0.0 h1:4DBwDE0NGyQoBHbLQYPwSUPoCMWR5BEzIk/f1lZbAQM=
 github.com/pmezard/go-difflib v1.0.0/go.mod h1:iKH77koFhYxTK1pcRnkKkqfTogsbg7gZNVY4sRDYZ/4=
 github.com/sebdah/goldie v0.0.0-20180424091453-8784dd1ab561 h1:IY+sDBJR/wRtsxq+626xJnt4Tw7/ROA9cDIR8MMhWyg=
 github.com/sebdah/goldie v0.0.0-20180424091453-8784dd1ab561/go.mod h1:lvjGftC8oe7XPtyrOidaMi0rp5B9+XY/ZRUynGnuaxQ=
 github.com/stretchr/objx v0.1.0/go.mod h1:HFkY916IF+rwdDfMAkV7OtwuqBVzrE8GR6GFx+wExME=
 github.com/stretchr/testify v1.3.0 h1:TivCn/peBQ7UY8ooIcPgZFpTNSz0Q2U6UrFlUfqbe0Q=
 github.com/stretchr/testify v1.3.0/go.mod h1:M5WIy9Dh21IEIfnGCwXGc5bZfKNJtfHm1UVUgZn+9EI=
+golang.org/x/sync v0.0.0-20181221193216-37e7f081c4d4 h1:YUO/7uOKsKeq9UokNS62b8FYywz3ker1l1vDZRCRefw=
+golang.org/x/sync v0.0.0-20181221193216-37e7f081c4d4/go.mod h1:RxMgew5VJxzue5/jJTE5uejpjVlOe/izrB70Jof72aM=
 gopkg.in/alecthomas/kingpin.v2 v2.2.6 h1:jMFz6MfLP0/4fUyZle81rXUoxOBFi19VUFKVDOQfozc=
 gopkg.in/alecthomas/kingpin.v2 v2.2.6/go.mod h1:FMv+mEhP44yOT+4EoQTLFTRgOQ1FBLkstjWtayDeSgw=

tag/fixtures/name.golden

@@ -0,0 +1,3 @@
+
+
+	test name

tag/fixtures/name_classifier.golden

@@ -0,0 +1,3 @@
+
+
+	test namefirst classifier

tag/fixtures/name_classifiers.golden

@@ -0,0 +1,3 @@
+
+0
+	test namefirst classifiersecond classifier

tag/set.go

@@ -0,0 +1,106 @@
+package tag
+
+import (
+	"github.com/corvus-ch/bilocation/tag/internal"
+	"github.com/golang/protobuf/proto"
+)
+
+// Set implements a set data structure for file tags.
+// Inspired by https://gist.github.com/bgadrian/cb8b9344d9c66571ef331a14eb7a2e80.
+type Set map[string]map[string]struct{}
+
+// NewTagSet returns a new tag set populated with the data read from the protocol buffer wire format data.
+func NewTagSet(data []byte) (Set, error) {
+	tags := &internal.Set{}
+	err := proto.Unmarshal(data, tags)
+	if err != nil {
+		return nil, err
+	}
+
+	s := Set{}
+
+	for _, tag := range tags.Tags {
+		s.Add(tag.Name, tag.Classifiers...)
+	}
+
+	return s, nil
+}
+
+// Has checks if name is present in the set.
+func (s Set) Has(name string) bool {
+	_, ok := s[name]
+	return ok
+}
+
+// HasClassifier checks if the name and classifier pair is present in the set.
+func (s Set) HasClassifier(name, classifier string) bool {
+	_, ok := s[name][classifier]
+	return ok
+}
+
+// Read returns the list of classifiers for name.
+func (s Set) Get(name string) []string {
+	t, ok := s[name]
+	if !ok {
+		return make([]string, 0)
+	}
+
+	r := make([]string, 0, len(t))
+
+	for c, _ := range t {
+		r = append(r, c)
+	}
+
+	return r
+}
+
+// Add adds name with an optional list of classifiers to the set.
+func (s Set) Add(name string, classifiers ...string) {
+	if _, ok := s[name]; !ok {
+		s[name] = make(map[string]struct{}, len(classifiers))
+	}
+
+	for _, classifier := range classifiers {
+		if _, ok := s[name][classifier]; !ok {
+			s[name][classifier] = struct{}{}
+		}
+	}
+}
+
+// Del deletes name with all its classifiers.
+func (s Set) Del(name string) {
+	delete(s, name)
+}
+
+// DelClassifier removes the classifier from name.
+func (s Set) DelClassifier(name, classifier string) {
+	if data, ok := s[name]; ok {
+		delete(data, classifier)
+		if len(data) == 0 {
+			delete(s, name)
+		}
+	}
+}
+
+// Size returns the number of tags in the set.
+func (s Set) Size() int {
+	return len(s)
+}
+
+// Bytes returns the set in the protocol buffer wire format.
+func (s Set) Bytes() ([]byte, error) {
+	set := &internal.Set{}
+	set.Tags = make([]*internal.Tag, 0, s.Size())
+
+	for name, classifiers := range s {
+		tag := &internal.Tag{Name: name}
+		tag.Classifiers = make([]string, 0, len(classifiers))
+		for classifier, _ := range classifiers {
+			if len(classifier) > 0 {
+				tag.Classifiers = append(tag.Classifiers, classifier)
+			}
+		}
+		set.Tags = append(set.Tags, tag)
+	}
+	return proto.Marshal(set)
+}