graphvent/lockable.go

479 lines
13 KiB
Go

package graphvent
import (
"encoding/json"
"fmt"
)
type ListenerExt struct {
Buffer int
Chan chan Signal
}
func NewListenerExt(buffer int) *ListenerExt {
return &ListenerExt{
Buffer: buffer,
Chan: make(chan Signal, buffer),
}
}
func LoadListenerExt(ctx *Context, data []byte) (Extension, error) {
var j int
err := json.Unmarshal(data, &j)
if err != nil {
return nil, err
}
return NewListenerExt(j), nil
}
const ListenerExtType = ExtType("LISTENER")
func (listener *ListenerExt) Type() ExtType {
return ListenerExtType
}
func (ext *ListenerExt) Process(ctx *Context, princ_id NodeID, node *Node, signal Signal) {
ctx.Log.Logf("signal", "LISTENER_PROCESS: %s - %+v", node.ID, signal)
select {
case ext.Chan <- signal:
default:
ctx.Log.Logf("listener", "LISTENER_OVERFLOW: %s", node.ID)
}
return
}
func LoadLockableExt(ctx *Context, data []byte) (Extension, error) {
var ext LockableExt
err := json.Unmarshal(data, &ext)
if err != nil {
return nil, err
}
ctx.Log.Logf("db", "DB_LOADING_LOCKABLE_EXT_JSON: %+v", ext)
return &ext, nil
}
func (ext *ListenerExt) Serialize() ([]byte, error) {
return json.MarshalIndent(ext.Buffer, "", " ")
}
const LockableExtType = ExtType("LOCKABLE")
func (ext *LockableExt) Type() ExtType {
return LockableExtType
}
func (ext *LockableExt) Serialize() ([]byte, error) {
return json.MarshalIndent(ext, "", " ")
}
func NewLockableExt() *LockableExt {
return &LockableExt{
Owner: nil,
PendingOwner: nil,
Requirements: map[NodeID]ReqState{},
Dependencies: map[NodeID]string{},
}
}
type ReqState struct {
Link string `json:"link"`
Lock string `json:"lock"`
}
type LockableExt struct {
Owner *NodeID `json:"owner"`
PendingOwner *NodeID `json:"pending_owner"`
Requirements map[NodeID]ReqState `json:"requirements"`
Dependencies map[NodeID]string `json:"dependencies"`
}
func UnlockLockable(ctx *Context, node *Node) error {
return ctx.Send(node.ID, node.ID, NewLockSignal("unlock"))
}
func LockLockable(ctx *Context, node *Node) error {
return ctx.Send(node.ID, node.ID, NewLockSignal("lock"))
}
func LinkRequirement(ctx *Context, dependency *Node, requirement NodeID) error {
dep_ext, err := GetExt[*LockableExt](dependency)
if err != nil {
return err
}
_, exists := dep_ext.Requirements[requirement]
if exists == true {
return fmt.Errorf("%s is already a requirement of %s", requirement, dependency.ID)
}
_, exists = dep_ext.Dependencies[requirement]
if exists == true {
return fmt.Errorf("%s is a dependency of %s, cannot link as requirement", requirement, dependency.ID)
}
dep_ext.Requirements[requirement] = ReqState{"linking", "unlocked"}
return ctx.Send(dependency.ID, requirement, NewLinkSignal("link_as_req"))
}
func (ext *LockableExt) HandleLockSignal(ctx *Context, source NodeID, node *Node, signal StateSignal) {
ctx.Log.Logf("lockable", "LOCK_SIGNAL: %s->%s %+v", source, node.ID, signal)
state := signal.State
switch state {
case "unlock":
if ext.Owner == nil {
ctx.Send(node.ID, source, NewLockSignal("already_unlocked"))
} else if source != *ext.Owner {
ctx.Send(node.ID, source, NewLockSignal("not_owner"))
} else if ext.PendingOwner == nil {
ctx.Send(node.ID, source, NewLockSignal("already_unlocking"))
} else {
if len(ext.Requirements) == 0 {
ext.Owner = nil
ext.PendingOwner = nil
ctx.Send(node.ID, source, NewLockSignal("unlocked"))
} else {
ext.PendingOwner = nil
for id, state := range(ext.Requirements) {
if state.Link == "linked" {
if state.Lock != "locked" {
panic("NOT_LOCKED")
}
state.Lock = "unlocking"
ext.Requirements[id] = state
ctx.Send(node.ID, id, NewLockSignal("unlock"))
}
}
if source != node.ID {
ctx.Send(node.ID, source, NewLockSignal("unlocking"))
}
}
}
case "unlocking":
state, exists := ext.Requirements[source]
if exists == false {
ctx.Send(node.ID, source, NewLockSignal("not_requirement"))
} else if state.Link != "linked" {
ctx.Send(node.ID, source, NewLockSignal("node_not_linked"))
} else if state.Lock != "unlocking" {
ctx.Send(node.ID, source, NewLockSignal("not_unlocking"))
}
case "unlocked":
if source == node.ID {
return
}
state, exists := ext.Requirements[source]
if exists == false {
ctx.Send(node.ID, source, NewLockSignal("not_requirement"))
} else if state.Link != "linked" {
ctx.Send(node.ID, source, NewLockSignal("not_linked"))
} else if state.Lock != "unlocking" {
ctx.Send(node.ID, source, NewLockSignal("not_unlocking"))
} else {
state.Lock = "unlocked"
ext.Requirements[source] = state
if ext.PendingOwner == nil {
linked := 0
unlocked := 0
for _, s := range(ext.Requirements) {
if s.Link == "linked" {
linked += 1
}
if s.Lock == "unlocked" {
unlocked += 1
}
}
if linked == unlocked {
previous_owner := *ext.Owner
ext.Owner = nil
ctx.Send(node.ID, previous_owner, NewLockSignal("unlocked"))
}
}
}
case "locked":
if source == node.ID {
return
}
state, exists := ext.Requirements[source]
if exists == false {
ctx.Send(node.ID, source, NewLockSignal("not_requirement"))
} else if state.Link != "linked" {
ctx.Send(node.ID, source, NewLockSignal("not_linked"))
} else if state.Lock != "locking" {
ctx.Send(node.ID, source, NewLockSignal("not_locking"))
} else {
state.Lock = "locked"
ext.Requirements[source] = state
if ext.PendingOwner != nil {
linked := 0
locked := 0
for _, s := range(ext.Requirements) {
if s.Link == "linked" {
linked += 1
}
if s.Lock == "locked" {
locked += 1
}
}
if linked == locked {
ext.Owner = ext.PendingOwner
ctx.Send(node.ID, *ext.Owner, NewLockSignal("locked"))
}
}
}
case "locking":
state, exists := ext.Requirements[source]
if exists == false {
ctx.Send(node.ID, source, NewLockSignal("not_requirement"))
} else if state.Link != "linked" {
ctx.Send(node.ID, source, NewLockSignal("node_not_linked"))
} else if state.Lock != "locking" {
ctx.Send(node.ID, source, NewLockSignal("not_locking"))
}
case "lock":
if ext.Owner != nil {
ctx.Send(node.ID, source, NewLockSignal("already_locked"))
} else if ext.PendingOwner != nil {
ctx.Send(node.ID, source, NewLockSignal("already_locking"))
} else {
owner := source
if len(ext.Requirements) == 0 {
ext.Owner = &owner
ext.PendingOwner = ext.Owner
ctx.Send(node.ID, source, NewLockSignal("locked"))
} else {
ext.PendingOwner = &owner
for id, state := range(ext.Requirements) {
if state.Link == "linked" {
if state.Lock != "unlocked" {
panic("NOT_UNLOCKED")
}
state.Lock = "locking"
ext.Requirements[id] = state
ctx.Send(node.ID, id, NewLockSignal("lock"))
}
}
if source != node.ID {
ctx.Send(node.ID, source, NewLockSignal("locking"))
}
}
}
default:
ctx.Log.Logf("lockable", "LOCK_ERR: unkown state %s", state)
}
}
// TODO: don't allow changes to requirements or dependencies while being locked or locked
// TODO: add unlink
func (ext *LockableExt) HandleLinkSignal(ctx *Context, source NodeID, node *Node, signal StateSignal) {
ctx.Log.Logf("lockable", "LINK_SIGNAL: %s->%s %+v", source, node.ID, signal)
state := signal.State
switch state {
case "link_as_dep":
state, exists := ext.Requirements[source]
if exists == true && state.Link == "linked" {
ctx.Send(node.ID, source, NewLinkSignal("already_req"))
} else if state.Link == "linking" {
state.Link = "linked"
ext.Requirements[source] = state
ctx.Send(node.ID, source, NewLinkSignal("linked_as_dep"))
} else if ext.PendingOwner != ext.Owner {
if ext.Owner == nil {
ctx.Send(node.ID, source, NewLinkSignal("locking"))
} else {
ctx.Send(node.ID, source, NewLinkSignal("unlocking"))
}
} else {
ext.Requirements[source] = ReqState{"linking", "unlocked"}
ctx.Send(node.ID, source, NewLinkSignal("link_as_req"))
}
case "link_as_req":
state, exists := ext.Dependencies[source]
if exists == true && state == "linked" {
ctx.Send(node.ID, source, NewLinkSignal("already_dep"))
} else if state == "linking" {
ext.Dependencies[source] = "linked"
ctx.Send(node.ID, source, NewLinkSignal("linked_as_req"))
} else if ext.PendingOwner != ext.Owner {
if ext.Owner == nil {
ctx.Send(node.ID, source, NewLinkSignal("locking"))
} else {
ctx.Send(node.ID, source, NewLinkSignal("unlocking"))
}
} else {
ext.Dependencies[source] = "linking"
ctx.Send(node.ID, source, NewLinkSignal("link_as_dep"))
}
case "linked_as_dep":
state, exists := ext.Dependencies[source]
if exists == false {
ctx.Send(node.ID, source, NewLinkSignal("not_linking"))
} else if state == "linked" {
} else if state == "linking" {
ext.Dependencies[source] = "linked"
ctx.Send(node.ID, source, NewLinkSignal("linked_as_req"))
}
ctx.Log.Logf("lockable", "%s is a dependency of %s", node.ID, source)
case "linked_as_req":
state, exists := ext.Requirements[source]
if exists == false {
ctx.Send(node.ID, source, NewLinkSignal("not_linking"))
} else if state.Link == "linked" {
} else if state.Link == "linking" {
state.Link = "linked"
ext.Requirements[source] = state
ctx.Send(node.ID, source, NewLinkSignal("linked_as_dep"))
}
ctx.Log.Logf("lockable", "%s is a requirement of %s", node.ID, source)
default:
ctx.Log.Logf("lockable", "LINK_ERROR: unknown state %s", state)
}
}
func (ext *LockableExt) Process(ctx *Context, source NodeID, node *Node, signal Signal) {
ctx.Log.Logf("signal", "LOCKABLE_PROCESS: %s", node.ID)
switch signal.Direction() {
case Up:
owner_sent := false
for dependency, state := range(ext.Dependencies) {
if state == "linked" {
err := ctx.Send(node.ID, dependency, signal)
if err != nil {
ctx.Log.Logf("signal", "LOCKABLE_SIGNAL_ERR: %s->%s - %e", node.ID, dependency, err)
}
if ext.Owner != nil {
if dependency == *ext.Owner {
owner_sent = true
}
}
}
}
if ext.Owner != nil && owner_sent == false {
if *ext.Owner != node.ID {
err := ctx.Send(node.ID, *ext.Owner, signal)
if err != nil {
ctx.Log.Logf("signal", "LOCKABLE_SIGNAL_ERR: %s->%s - %e", node.ID, *ext.Owner, err)
}
}
}
case Down:
for requirement, state := range(ext.Requirements) {
if state.Link == "linked" {
err := ctx.Send(node.ID, requirement, signal)
if err != nil {
ctx.Log.Logf("signal", "LOCKABLE_SIGNAL_ERR: %s->%s - %e", node.ID, requirement, err)
}
}
}
case Direct:
switch signal.Type() {
case LinkSignalType:
ext.HandleLinkSignal(ctx, source, node, signal.(StateSignal))
case LockSignalType:
ext.HandleLockSignal(ctx, source, node, signal.(StateSignal))
default:
}
default:
}
}
func SaveNode(node *Node) string {
str := ""
if node != nil {
str = node.ID.String()
}
return str
}
func RestoreNode(ctx *Context, id_str string) (*Node, error) {
if id_str == "" {
return nil, nil
}
id, err := ParseID(id_str)
if err != nil {
return nil, err
}
return LoadNode(ctx, id)
}
func SaveNodeMap(nodes NodeMap) map[string]string {
m := map[string]string{}
for id, node := range(nodes) {
m[id.String()] = SaveNode(node)
}
return m
}
func RestoreNodeMap(ctx *Context, ids map[string]string) (NodeMap, error) {
nodes := NodeMap{}
for id_str_1, id_str_2 := range(ids) {
id_1, err := ParseID(id_str_1)
if err != nil {
return nil, err
}
node_1, err := LoadNode(ctx, id_1)
if err != nil {
return nil, err
}
var node_2 *Node = nil
if id_str_2 != "" {
id_2, err := ParseID(id_str_2)
if err != nil {
return nil, err
}
node_2, err = LoadNode(ctx, id_2)
if err != nil {
return nil, err
}
}
nodes[node_1.ID] = node_2
}
return nodes, nil
}
func SaveNodeList(nodes NodeMap) []string {
ids := make([]string, len(nodes))
i := 0
for id, _ := range(nodes) {
ids[i] = id.String()
i += 1
}
return ids
}
func RestoreNodeList(ctx *Context, ids []string) (NodeMap, error) {
nodes := NodeMap{}
for _, id_str := range(ids) {
node, err := RestoreNode(ctx, id_str)
if err != nil {
return nil, err
}
nodes[node.ID] = node
}
return nodes, nil
}