initial implementation of scan, parse, and satisfies

README.md

@@ -1,2 +1,22 @@
 # spdx-expression
+
 Golang implementation of a checker for determining if an SPDX ID satisfies an SPDX Expression.
+
+Public API:
+
+```go
+Parse(expression string) (*Node, error)
+Satisfies(spdxID string, expression string)
+```
+
+Example expressions:
+
+```go
+"MIT"
+"MIT AND Apache-2.0"
+"MIT OR Apache-2.0"
+"MIT AND (Apache-1.0 OR Apache-2.0)"
+"Apache-1.0+"
+"DocumentRef-spdx-tool-1.2:LicenseRef-MIT-Style-2"
+"GPL-2.0 WITH Bison-exception-2.2"
+```

go.mod

@@ -0,0 +1,10 @@
+module github.com/github/spdx-expression
+
+go 1.18
+
+require (
+	github.com/davecgh/go-spew v1.1.1 // indirect
+	github.com/pmezard/go-difflib v1.0.0 // indirect
+	github.com/stretchr/testify v1.8.0 // indirect
+	gopkg.in/yaml.v3 v3.0.1 // indirect
+)

go.sum

@@ -0,0 +1,14 @@
+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/pmezard/go-difflib v1.0.0 h1:4DBwDE0NGyQoBHbLQYPwSUPoCMWR5BEzIk/f1lZbAQM=
+github.com/pmezard/go-difflib v1.0.0/go.mod h1:iKH77koFhYxTK1pcRnkKkqfTogsbg7gZNVY4sRDYZ/4=
+github.com/stretchr/objx v0.1.0/go.mod h1:HFkY916IF+rwdDfMAkV7OtwuqBVzrE8GR6GFx+wExME=
+github.com/stretchr/objx v0.4.0/go.mod h1:YvHI0jy2hoMjB+UWwv71VJQ9isScKT/TqJzVSSt89Yw=
+github.com/stretchr/testify v1.7.1/go.mod h1:6Fq8oRcR53rry900zMqJjRRixrwX3KX962/h/Wwjteg=
+github.com/stretchr/testify v1.8.0 h1:pSgiaMZlXftHpm5L7V1+rVB+AZJydKsMxsQBIJw4PKk=
+github.com/stretchr/testify v1.8.0/go.mod h1:yNjHg4UonilssWZ8iaSj1OCr/vHnekPRkoO+kdMU+MU=
+gopkg.in/check.v1 v0.0.0-20161208181325-20d25e280405/go.mod h1:Co6ibVJAznAaIkqp8huTwlJQCZ016jof/cbN4VW5Yz0=
+gopkg.in/yaml.v3 v3.0.0-20200313102051-9f266ea9e77c/go.mod h1:K4uyk7z7BCEPqu6E+C64Yfv1cQ7kz7rIZviUmN+EgEM=
+gopkg.in/yaml.v3 v3.0.1 h1:fxVm/GzAzEWqLHuvctI91KS9hhNmmWOoWu0XTYJS7CA=
+gopkg.in/yaml.v3 v3.0.1/go.mod h1:K4uyk7z7BCEPqu6E+C64Yfv1cQ7kz7rIZviUmN+EgEM=

spdxexp/compare.go

@@ -0,0 +1,38 @@
+package spdxexp
+
+func compareGT(first *Node, second *Node) bool {
+	firstRange := GetLicenseRange(*first.License())
+	secondRange := GetLicenseRange(*second.License())
+
+	if !sameLicenseGroup(firstRange, secondRange) {
+		return false
+	}
+	return firstRange.Location[VERSION_GROUP] > secondRange.Location[VERSION_GROUP]
+}
+
+func compareLT(first *Node, second *Node) bool {
+	firstRange := GetLicenseRange(*first.License())
+	secondRange := GetLicenseRange(*second.License())
+
+	if !sameLicenseGroup(firstRange, secondRange) {
+		return false
+	}
+	return firstRange.Location[VERSION_GROUP] < secondRange.Location[VERSION_GROUP]
+}
+
+func compareEQ(first *Node, second *Node) bool {
+	firstRange := GetLicenseRange(*first.License())
+	secondRange := GetLicenseRange(*second.License())
+
+	if !sameLicenseGroup(firstRange, secondRange) {
+		return false
+	}
+	return firstRange.Location[VERSION_GROUP] == secondRange.Location[VERSION_GROUP]
+}
+
+func sameLicenseGroup(firstRange *LicenseRange, secondRange *LicenseRange) bool {
+	if firstRange == nil || secondRange == nil || firstRange.Location[LICENSE_GROUP] != secondRange.Location[LICENSE_GROUP] {
+		return false
+	}
+	return true
+}

spdxexp/compare_test.go

@@ -0,0 +1,94 @@
+package spdxexp
+
+import (
+	"testing"
+
+	"github.com/stretchr/testify/assert"
+)
+
+func TestCompareGT(t *testing.T) {
+	tests := []struct {
+		name   string
+		first  *Node
+		second *Node
+		result bool
+	}{
+		{"expect greater than: GPL-3.0 > GPL-2.0", getLicenseNode("GPL-3.0", false), getLicenseNode("GPL-2.0", false), true},
+		{"expect greater than: GPL-3.0-only > GPL-2.0-only", getLicenseNode("GPL-3.0-only", false), getLicenseNode("GPL-2.0-only", false), true},
+		{"expect greater than: LPPL-1.3a > LPPL-1.0", getLicenseNode("LPPL-1.3a", false), getLicenseNode("LPPL-1.0", false), true},
+		{"expect greater than: LPPL-1.3c > LPPL-1.3a", getLicenseNode("LPPL-1.3c", false), getLicenseNode("LPPL-1.3a", false), true},
+		{"expect greater than: AGPL-3.0 > AGPL-1.0", getLicenseNode("AGPL-3.0", false), getLicenseNode("AGPL-1.0", false), true},
+		{"expect greater than: GPL-2.0-or-later > GPL-2.0-only", getLicenseNode("GPL-2.0-or-later", true), getLicenseNode("GPL-2.0-only", false), true}, // TODO: Double check that -or-later and -only should be true for GT
+		{"expect greater than: GPL-2.0-or-later > GPL-2.0", getLicenseNode("GPL-2.0-or-later", true), getLicenseNode("GPL-2.0", false), true},
+		{"expect equal: GPL-3.0 > GPL-3.0", getLicenseNode("GPL-3.0", false), getLicenseNode("GPL-3.0", false), false},
+		{"expect less than: MPL-1.0 > MPL-2.0", getLicenseNode("MPL-1.0", false), getLicenseNode("MPL-2.0", false), false},
+		{"incompatible: MIT > ISC", getLicenseNode("MIT", false), getLicenseNode("ISC", false), false},
+		{"incompatible: OSL-1.0 > OPL-1.0", getLicenseNode("OSL-1.0", false), getLicenseNode("OPL-1.0", false), false},
+		{"not simple license: (MIT OR ISC) > GPL-3.0", getLicenseNode("(MIT OR ISC)", false), getLicenseNode("GPL-3.0", false), false}, // TODO: should it raise error?
+	}
+
+	for _, test := range tests {
+		test := test
+		t.Run(test.name, func(t *testing.T) {
+			assert.Equal(t, test.result, compareGT(test.first, test.second))
+		})
+	}
+}
+
+func TestCompareEQ(t *testing.T) {
+	tests := []struct {
+		name   string
+		first  *Node
+		second *Node
+		result bool
+	}{
+		{"expect greater than: GPL-3.0 == GPL-2.0", getLicenseNode("GPL-3.0", false), getLicenseNode("GPL-2.0", false), false},
+		{"expect greater than: GPL-3.0-only == GPL-2.0-only", getLicenseNode("GPL-3.0-only", false), getLicenseNode("GPL-2.0-only", false), false},
+		{"expect greater than: LPPL-1.3a == LPPL-1.0", getLicenseNode("LPPL-1.3a", false), getLicenseNode("LPPL-1.0", false), false},
+		{"expect greater than: LPPL-1.3c == LPPL-1.3a", getLicenseNode("LPPL-1.3c", false), getLicenseNode("LPPL-1.3a", false), false},
+		{"expect greater than: AGPL-3.0 == AGPL-1.0", getLicenseNode("AGPL-3.0", false), getLicenseNode("AGPL-1.0", false), false},
+		{"expect greater than: GPL-2.0-or-later == GPL-2.0-only", getLicenseNode("GPL-2.0-or-later", true), getLicenseNode("GPL-2.0-only", false), false},
+		{"expect greater than: GPL-2.0-or-later == GPL-2.0", getLicenseNode("GPL-2.0-or-later", true), getLicenseNode("GPL-2.0", false), false},
+		{"expect equal: GPL-3.0 == GPL-3.0", getLicenseNode("GPL-3.0", false), getLicenseNode("GPL-3.0", false), true},
+		{"expect less than: MPL-1.0 == MPL-2.0", getLicenseNode("MPL-1.0", false), getLicenseNode("MPL-2.0", false), false},
+		{"incompatible: MIT == ISC", getLicenseNode("MIT", false), getLicenseNode("ISC", false), false},
+		{"incompatible: OSL-1.0 == OPL-1.0", getLicenseNode("OSL-1.0", false), getLicenseNode("OPL-1.0", false), false},
+		{"not simple license: (MIT OR ISC) == GPL-3.0", getLicenseNode("(MIT OR ISC)", false), getLicenseNode("GPL-3.0", false), false}, // TODO: should it raise error?
+	}
+
+	for _, test := range tests {
+		test := test
+		t.Run(test.name, func(t *testing.T) {
+			assert.Equal(t, test.result, compareEQ(test.first, test.second))
+		})
+	}
+}
+
+func TestCompareLT(t *testing.T) {
+	tests := []struct {
+		name   string
+		first  *Node
+		second *Node
+		result bool
+	}{
+		{"expect greater than: GPL-3.0 < GPL-2.0", getLicenseNode("GPL-3.0", false), getLicenseNode("GPL-2.0", false), false},
+		{"expect greater than: GPL-3.0-only < GPL-2.0-only", getLicenseNode("GPL-3.0-only", false), getLicenseNode("GPL-2.0-only", false), false},
+		{"expect greater than: LPPL-1.3a < LPPL-1.0", getLicenseNode("LPPL-1.3a", false), getLicenseNode("LPPL-1.0", false), false},
+		{"expect greater than: LPPL-1.3c < LPPL-1.3a", getLicenseNode("LPPL-1.3c", false), getLicenseNode("LPPL-1.3a", false), false},
+		{"expect greater than: AGPL-3.0 < AGPL-1.0", getLicenseNode("AGPL-3.0", false), getLicenseNode("AGPL-1.0", false), false},
+		{"expect greater than: GPL-2.0-or-later < GPL-2.0-only", getLicenseNode("GPL-2.0-or-later", true), getLicenseNode("GPL-2.0-only", false), false},
+		{"expect greater than: GPL-2.0-or-later == GPL-2.0", getLicenseNode("GPL-2.0-or-later", true), getLicenseNode("GPL-2.0", false), false},
+		{"expect equal: GPL-3.0 < GPL-3.0", getLicenseNode("GPL-3.0", false), getLicenseNode("GPL-3.0", false), false},
+		{"expect less than: MPL-1.0 < MPL-2.0", getLicenseNode("MPL-1.0", false), getLicenseNode("MPL-2.0", false), true},
+		{"incompatible: MIT < ISC", getLicenseNode("MIT", false), getLicenseNode("ISC", false), false},
+		{"incompatible: OSL-1.0 < OPL-1.0", getLicenseNode("OSL-1.0", false), getLicenseNode("OPL-1.0", false), false},
+		{"not simple license: (MIT OR ISC) < GPL-3.0", getLicenseNode("(MIT OR ISC)", false), getLicenseNode("GPL-3.0", false), false}, // TODO: should it raise error?
+	}
+
+	for _, test := range tests {
+		test := test
+		t.Run(test.name, func(t *testing.T) {
+			assert.Equal(t, test.result, compareLT(test.first, test.second))
+		})
+	}
+}