1 files changed, 204 insertions, 0 deletions
diff --git a/vendor/github.com/hashicorp/go-version/constraint.go b/vendor/github.com/hashicorp/go-version/constraint.go
new file mode 100644
index 000000000..d05575961
--- /dev/null
+++ b/vendor/github.com/hashicorp/go-version/constraint.go
@@ -0,0 +1,204 @@
+package version
+
+import (
+	"fmt"
+	"reflect"
+	"regexp"
+	"strings"
+)
+
+// Constraint represents a single constraint for a version, such as
+// ">= 1.0".
+type Constraint struct {
+	f        constraintFunc
+	check    *Version
+	original string
+}
+
+// Constraints is a slice of constraints. We make a custom type so that
+// we can add methods to it.
+type Constraints []*Constraint
+
+type constraintFunc func(v, c *Version) bool
+
+var constraintOperators map[string]constraintFunc
+
+var constraintRegexp *regexp.Regexp
+
+func init() {
+	constraintOperators = map[string]constraintFunc{
+		"":   constraintEqual,
+		"=":  constraintEqual,
+		"!=": constraintNotEqual,
+		">":  constraintGreaterThan,
+		"<":  constraintLessThan,
+		">=": constraintGreaterThanEqual,
+		"<=": constraintLessThanEqual,
+		"~>": constraintPessimistic,
+	}
+
+	ops := make([]string, 0, len(constraintOperators))
+	for k := range constraintOperators {
+		ops = append(ops, regexp.QuoteMeta(k))
+	}
+
+	constraintRegexp = regexp.MustCompile(fmt.Sprintf(
+		`^\s*(%s)\s*(%s)\s*$`,
+		strings.Join(ops, "|"),
+		VersionRegexpRaw))
+}
+
+// NewConstraint will parse one or more constraints from the given
+// constraint string. The string must be a comma-separated list of
+// constraints.
+func NewConstraint(v string) (Constraints, error) {
+	vs := strings.Split(v, ",")
+	result := make([]*Constraint, len(vs))
+	for i, single := range vs {
+		c, err := parseSingle(single)
+		if err != nil {
+			return nil, err
+		}
+
+		result[i] = c
+	}
+
+	return Constraints(result), nil
+}
+
+// Check tests if a version satisfies all the constraints.
+func (cs Constraints) Check(v *Version) bool {
+	for _, c := range cs {
+		if !c.Check(v) {
+			return false
+		}
+	}
+
+	return true
+}
+
+// Returns the string format of the constraints
+func (cs Constraints) String() string {
+	csStr := make([]string, len(cs))
+	for i, c := range cs {
+		csStr[i] = c.String()
+	}
+
+	return strings.Join(csStr, ",")
+}
+
+// Check tests if a constraint is validated by the given version.
+func (c *Constraint) Check(v *Version) bool {
+	return c.f(v, c.check)
+}
+
+func (c *Constraint) String() string {
+	return c.original
+}
+
+func parseSingle(v string) (*Constraint, error) {
+	matches := constraintRegexp.FindStringSubmatch(v)
+	if matches == nil {
+		return nil, fmt.Errorf("Malformed constraint: %s", v)
+	}
+
+	check, err := NewVersion(matches[2])
+	if err != nil {
+		return nil, err
+	}
+
+	return &Constraint{
+		f:        constraintOperators[matches[1]],
+		check:    check,
+		original: v,
+	}, nil
+}
+
+func prereleaseCheck(v, c *Version) bool {
+	switch vPre, cPre := v.Prerelease() != "", c.Prerelease() != ""; {
+	case cPre && vPre:
+		// A constraint with a pre-release can only match a pre-release version
+		// with the same base segments.
+		return reflect.DeepEqual(c.Segments64(), v.Segments64())
+
+	case !cPre && vPre:
+		// A constraint without a pre-release can only match a version without a
+		// pre-release.
+		return false
+
+	case cPre && !vPre:
+		// OK, except with the pessimistic operator
+	case !cPre && !vPre:
+		// OK
+	}
+	return true
+}
+
+//-------------------------------------------------------------------
+// Constraint functions
+//-------------------------------------------------------------------
+
+func constraintEqual(v, c *Version) bool {
+	return v.Equal(c)
+}
+
+func constraintNotEqual(v, c *Version) bool {
+	return !v.Equal(c)
+}
+
+func constraintGreaterThan(v, c *Version) bool {
+	return prereleaseCheck(v, c) && v.Compare(c) == 1
+}
+
+func constraintLessThan(v, c *Version) bool {
+	return prereleaseCheck(v, c) && v.Compare(c) == -1
+}
+
+func constraintGreaterThanEqual(v, c *Version) bool {
+	return prereleaseCheck(v, c) && v.Compare(c) >= 0
+}
+
+func constraintLessThanEqual(v, c *Version) bool {
+	return prereleaseCheck(v, c) && v.Compare(c) <= 0
+}
+
+func constraintPessimistic(v, c *Version) bool {
+	// Using a pessimistic constraint with a pre-release, restricts versions to pre-releases
+	if !prereleaseCheck(v, c) || (c.Prerelease() != "" && v.Prerelease() == "") {
+		return false
+	}
+
+	// If the version being checked is naturally less than the constraint, then there
+	// is no way for the version to be valid against the constraint
+	if v.LessThan(c) {
+		return false
+	}
+	// We'll use this more than once, so grab the length now so it's a little cleaner
+	// to write the later checks
+	cs := len(c.segments)
+
+	// If the version being checked has less specificity than the constraint, then there
+	// is no way for the version to be valid against the constraint
+	if cs > len(v.segments) {
+		return false
+	}
+
+	// Check the segments in the constraint against those in the version. If the version
+	// being checked, at any point, does not have the same values in each index of the
+	// constraints segments, then it cannot be valid against the constraint.
+	for i := 0; i < c.si-1; i++ {
+		if v.segments[i] != c.segments[i] {
+			return false
+		}
+	}
+
+	// Check the last part of the segment in the constraint. If the version segment at
+	// this index is less than the constraints segment at this index, then it cannot
+	// be valid against the constraint
+	if c.segments[cs-1] > v.segments[cs-1] {
+		return false
+	}
+
+	// If nothing has rejected the version by now, it's valid
+	return true
+}