Added Prerelase and BuildMetadata getters for Version and RelaxedVersion

Author: cmaglie

Diff for: relaxed_version.go

@@ -118,3 +118,39 @@ func (v *RelaxedVersion) SortableString() string {
 	}
 	return ":" + string(v.customversion)
 }
+
+// IsPrerelase returns true if the version is valid semver and has a pre-release part
+// otherwise it returns false.
+func (v *RelaxedVersion) IsPrerelase() bool {
+	if v.version == nil {
+		return false
+	}
+	return v.version.IsPrerelase()
+}
+
+// Prerelease returns the pre-release part of the version if the version is valid semver
+// otherwise it returns an empty string.
+func (v *RelaxedVersion) Prerelease() string {
+	if v.version == nil {
+		return ""
+	}
+	return v.version.Prerelease()
+}
+
+// HasBuildMetadata returns true if the version is valid semver and has a build metadata part
+// otherwise it returns false.
+func (v *RelaxedVersion) HasBuildMetadata() bool {
+	if v.version == nil {
+		return false
+	}
+	return v.version.HasBuildMetadata()
+}
+
+// BuildMetadata returns the build metadata part of the version if the version is valid semver
+// otherwise it returns an empty string.
+func (v *RelaxedVersion) BuildMetadata() string {
+	if v.version == nil {
+		return ""
+	}
+	return v.version.BuildMetadata()
+}

Diff for: version.go

@@ -494,3 +494,29 @@ func (v *Version) SortableString() string {
 	add(prerelease[start:])
 	return res
 }
+
+// IsPrerelase returns true if the version has a pre-release part
+func (v *Version) IsPrerelase() bool {
+	return v.prerelease != v.patch
+}
+
+// Prerelease returns the pre-release part of the version
+func (v *Version) Prerelease() string {
+	if !v.IsPrerelase() {
+		return ""
+	}
+	return v.raw[v.patch+1 : v.prerelease]
+}
+
+// HasBuildMetadata returns true if the version has a build metadata part
+func (v *Version) HasBuildMetadata() bool {
+	return v.build != v.prerelease
+}
+
+// BuildMetadata returns the build metadata part of the version
+func (v *Version) BuildMetadata() string {
+	if !v.HasBuildMetadata() {
+		return ""
+	}
+	return v.raw[v.prerelease+1 : v.build]
+}

Diff for: version_test.go

@@ -305,3 +305,59 @@ func TestCompareNumbers(t *testing.T) {
 	testGreater("10", "1")
 	testGreater("10", "2")
 }
+
+func TestVersionGetters(t *testing.T) {
+	type test struct {
+		version    string
+		prerelease string
+		build      string
+	}
+	tests := []test{
+		{"", "", ""},
+		{"0", "", ""},
+		{"1", "", ""},
+		{"0.1", "", ""},
+		{"1.1", "", ""},
+		{"0.2.3", "", ""},
+		{"1.2.3-aaa", "aaa", ""},
+		{"0.2-aaa", "aaa", ""},
+		{"1-aaa", "aaa", ""},
+		{"0.2.3+bbb", "", "bbb"},
+		{"1.3+bbb", "", "bbb"},
+		{"0+bbb", "", "bbb"},
+		{"1.2.3-aaa+bbb", "aaa", "bbb"},
+		{"0.2-aaa+bbb", "aaa", "bbb"},
+		{"1-aaa+bbb", "aaa", "bbb"},
+		{"0.2.3-aaa.4.5.6+bbb.7.8.9", "aaa.4.5.6", "bbb.7.8.9"},
+	}
+	for _, tt := range tests {
+		v := MustParse(tt.version)
+		require.Equal(t, tt.version, v.String())
+		require.Equal(t, tt.prerelease != "", v.IsPrerelase())
+		require.Equal(t, tt.prerelease, v.Prerelease())
+		require.Equal(t, tt.build != "", v.HasBuildMetadata())
+		require.Equal(t, tt.build, v.BuildMetadata())
+		r := ParseRelaxed(tt.version)
+		require.Equal(t, tt.version, r.String())
+		require.Equal(t, tt.prerelease != "", r.IsPrerelase())
+		require.Equal(t, tt.prerelease, r.Prerelease())
+		require.Equal(t, tt.build != "", r.HasBuildMetadata())
+		require.Equal(t, tt.build, r.BuildMetadata())
+	}
+	relaxedTests := []test{
+		{"asd", "", ""},
+		{"123.123.123.123-123", "", ""},
+		{"1.2.3-a@very@fancy@version", "", ""},
+	}
+	for _, tt := range relaxedTests {
+		v, err := Parse(tt.version)
+		require.Error(t, err, "should not parse %s", tt.version)
+		require.Nil(t, v)
+		r := ParseRelaxed(tt.version)
+		require.Equal(t, tt.version, r.String())
+		require.Equal(t, tt.prerelease != "", r.IsPrerelase())
+		require.Equal(t, tt.prerelease, r.Prerelease())
+		require.Equal(t, tt.build != "", r.HasBuildMetadata())
+		require.Equal(t, tt.build, r.BuildMetadata())
+	}
+}