initial commit

Signed-off-by: Derek McQuay <derekmcquay@gmail.com>

vendor/cloud.google.com/go/bigtable/gc.go

@@ -0,0 +1,158 @@
+/*
+Copyright 2015 Google Inc. 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 bigtable
+
+import (
+	"fmt"
+	"strings"
+	"time"
+
+	durpb "github.com/golang/protobuf/ptypes/duration"
+	bttdpb "google.golang.org/genproto/googleapis/bigtable/admin/v2"
+)
+
+// A GCPolicy represents a rule that determines which cells are eligible for garbage collection.
+type GCPolicy interface {
+	String() string
+	proto() *bttdpb.GcRule
+}
+
+// IntersectionPolicy returns a GC policy that only applies when all its sub-policies apply.
+func IntersectionPolicy(sub ...GCPolicy) GCPolicy { return intersectionPolicy{sub} }
+
+type intersectionPolicy struct {
+	sub []GCPolicy
+}
+
+func (ip intersectionPolicy) String() string {
+	var ss []string
+	for _, sp := range ip.sub {
+		ss = append(ss, sp.String())
+	}
+	return "(" + strings.Join(ss, " && ") + ")"
+}
+
+func (ip intersectionPolicy) proto() *bttdpb.GcRule {
+	inter := &bttdpb.GcRule_Intersection{}
+	for _, sp := range ip.sub {
+		inter.Rules = append(inter.Rules, sp.proto())
+	}
+	return &bttdpb.GcRule{
+		Rule: &bttdpb.GcRule_Intersection_{Intersection: inter},
+	}
+}
+
+// UnionPolicy returns a GC policy that applies when any of its sub-policies apply.
+func UnionPolicy(sub ...GCPolicy) GCPolicy { return unionPolicy{sub} }
+
+type unionPolicy struct {
+	sub []GCPolicy
+}
+
+func (up unionPolicy) String() string {
+	var ss []string
+	for _, sp := range up.sub {
+		ss = append(ss, sp.String())
+	}
+	return "(" + strings.Join(ss, " || ") + ")"
+}
+
+func (up unionPolicy) proto() *bttdpb.GcRule {
+	union := &bttdpb.GcRule_Union{}
+	for _, sp := range up.sub {
+		union.Rules = append(union.Rules, sp.proto())
+	}
+	return &bttdpb.GcRule{
+		Rule: &bttdpb.GcRule_Union_{Union: union},
+	}
+}
+
+// MaxVersionsPolicy returns a GC policy that applies to all versions of a cell
+// except for the most recent n.
+func MaxVersionsPolicy(n int) GCPolicy { return maxVersionsPolicy(n) }
+
+type maxVersionsPolicy int
+
+func (mvp maxVersionsPolicy) String() string { return fmt.Sprintf("versions() > %d", int(mvp)) }
+
+func (mvp maxVersionsPolicy) proto() *bttdpb.GcRule {
+	return &bttdpb.GcRule{Rule: &bttdpb.GcRule_MaxNumVersions{MaxNumVersions: int32(mvp)}}
+}
+
+// MaxAgePolicy returns a GC policy that applies to all cells
+// older than the given age.
+func MaxAgePolicy(d time.Duration) GCPolicy { return maxAgePolicy(d) }
+
+type maxAgePolicy time.Duration
+
+var units = []struct {
+	d      time.Duration
+	suffix string
+}{
+	{24 * time.Hour, "d"},
+	{time.Hour, "h"},
+	{time.Minute, "m"},
+}
+
+func (ma maxAgePolicy) String() string {
+	d := time.Duration(ma)
+	for _, u := range units {
+		if d%u.d == 0 {
+			return fmt.Sprintf("age() > %d%s", d/u.d, u.suffix)
+		}
+	}
+	return fmt.Sprintf("age() > %d", d/time.Microsecond)
+}
+
+func (ma maxAgePolicy) proto() *bttdpb.GcRule {
+	// This doesn't handle overflows, etc.
+	// Fix this if people care about GC policies over 290 years.
+	ns := time.Duration(ma).Nanoseconds()
+	return &bttdpb.GcRule{
+		Rule: &bttdpb.GcRule_MaxAge{MaxAge: &durpb.Duration{
+			Seconds: ns / 1e9,
+			Nanos:   int32(ns % 1e9),
+		}},
+	}
+}
+
+// GCRuleToString converts the given GcRule proto to a user-visible string.
+func GCRuleToString(rule *bttdpb.GcRule) string {
+	if rule == nil {
+		return "<default>"
+	}
+	switch r := rule.Rule.(type) {
+	case *bttdpb.GcRule_MaxNumVersions:
+		return MaxVersionsPolicy(int(r.MaxNumVersions)).String()
+	case *bttdpb.GcRule_MaxAge:
+		return MaxAgePolicy(time.Duration(r.MaxAge.Seconds) * time.Second).String()
+	case *bttdpb.GcRule_Intersection_:
+		return joinRules(r.Intersection.Rules, " && ")
+	case *bttdpb.GcRule_Union_:
+		return joinRules(r.Union.Rules, " || ")
+	default:
+		return ""
+	}
+}
+
+func joinRules(rules []*bttdpb.GcRule, sep string) string {
+	var chunks []string
+	for _, r := range rules {
+		chunks = append(chunks, GCRuleToString(r))
+	}
+	return "(" + strings.Join(chunks, sep) + ")"
+}