268 lines
8.4 KiB
Go
268 lines
8.4 KiB
Go
package graphvent
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import (
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"github.com/google/uuid"
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)
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type ReqState byte
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const (
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Unlocked = ReqState(0)
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Unlocking = ReqState(1)
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Locked = ReqState(2)
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Locking = ReqState(3)
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AbortingLock = ReqState(4)
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)
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type LockableExt struct{
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State ReqState `ext:""`
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ReqID *uuid.UUID `ext:""`
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Owner *NodeID `ext:""`
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PendingOwner *NodeID `ext:""`
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Requirements map[NodeID]ReqState `ext:""`
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}
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func (ext *LockableExt) Type() ExtType {
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return LockableExtType
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}
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func NewLockableExt(requirements []NodeID) *LockableExt {
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var reqs map[NodeID]ReqState = nil
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if requirements != nil {
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reqs = map[NodeID]ReqState{}
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for _, id := range(requirements) {
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reqs[id] = Unlocked
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}
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}
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return &LockableExt{
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State: Unlocked,
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Owner: nil,
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PendingOwner: nil,
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Requirements: reqs,
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}
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}
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// Send the signal to unlock a node from itself
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func UnlockLockable(ctx *Context, owner *Node, target NodeID) (uuid.UUID, error) {
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msgs := Messages{}
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signal := NewLockSignal("unlock")
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msgs = msgs.Add(ctx, owner.ID, owner.Key, signal, target)
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return signal.Header().ID, ctx.Send(msgs)
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}
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// Send the signal to lock a node from itself
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func LockLockable(ctx *Context, owner *Node, target NodeID) (uuid.UUID, error) {
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msgs := Messages{}
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signal := NewLockSignal("lock")
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msgs = msgs.Add(ctx, owner.ID, owner.Key, signal, target)
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return signal.Header().ID, ctx.Send(msgs)
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}
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func (ext *LockableExt) HandleErrorSignal(ctx *Context, node *Node, source NodeID, signal *ErrorSignal) Messages {
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str := signal.Error
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ctx.Log.Logf("lockable", "ERROR_SIGNAL: %s->%s %+v", source, node.ID, str)
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msgs := Messages {}
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switch str {
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case "not_unlocked":
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if ext.State == Locking {
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ext.State = AbortingLock
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ext.Requirements[source] = Unlocked
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for id, state := range(ext.Requirements) {
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if state == Locked {
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ext.Requirements[id] = Unlocking
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msgs = msgs.Add(ctx, node.ID, node.Key, NewLockSignal("unlock"), id)
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}
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}
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}
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case "not_locked":
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panic("RECEIVED not_locked, meaning a node thought it held a lock it didn't")
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case "not_requirement":
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}
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return msgs
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}
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func (ext *LockableExt) HandleLinkSignal(ctx *Context, node *Node, source NodeID, signal *LinkSignal) Messages {
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msgs := Messages {}
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if ext.State == Unlocked {
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switch signal.Action {
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case "add":
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_, exists := ext.Requirements[signal.NodeID]
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if exists == true {
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msgs = msgs.Add(ctx, node.ID, node.Key, NewErrorSignal(signal.ID, "already_requirement"), source)
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} else {
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if ext.Requirements == nil {
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ext.Requirements = map[NodeID]ReqState{}
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}
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ext.Requirements[signal.NodeID] = Unlocked
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msgs = msgs.Add(ctx, node.ID, node.Key, NewErrorSignal(signal.ID, "req_added"), source)
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}
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case "remove":
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_, exists := ext.Requirements[signal.NodeID]
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if exists == false {
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msgs = msgs.Add(ctx, node.ID, node.Key, NewErrorSignal(signal.ID, "not_requirement"), source)
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} else {
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delete(ext.Requirements, signal.NodeID)
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msgs = msgs.Add(ctx, node.ID, node.Key, NewErrorSignal(signal.ID, "req_removed"), source)
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}
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default:
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msgs = msgs.Add(ctx, node.ID, node.Key, NewErrorSignal(signal.ID, "unknown_action"), source)
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}
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} else {
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msgs = msgs.Add(ctx, node.ID, node.Key, NewErrorSignal(signal.ID, "not_unlocked"), source)
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}
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return msgs
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}
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// Handle a LockSignal and update the extensions owner/requirement states
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func (ext *LockableExt) HandleLockSignal(ctx *Context, node *Node, source NodeID, signal *LockSignal) Messages {
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ctx.Log.Logf("lockable", "LOCK_SIGNAL: %s->%s %+v", source, node.ID, signal.State)
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msgs := Messages{}
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switch signal.State {
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case "locked":
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state, found := ext.Requirements[source]
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if found == false {
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msgs = msgs.Add(ctx, node.ID, node.Key, NewErrorSignal(signal.ID, "not_requirement"), source)
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} else if state == Locking {
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if ext.State == Locking {
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ext.Requirements[source] = Locked
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reqs := 0
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locked := 0
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for _, s := range(ext.Requirements) {
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reqs += 1
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if s == Locked {
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locked += 1
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}
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}
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if locked == reqs {
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ext.State = Locked
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ext.Owner = ext.PendingOwner
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msgs = msgs.Add(ctx, node.ID, node.Key, NewLockSignal("locked"), *ext.Owner)
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} else {
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ctx.Log.Logf("lockable", "PARTIAL LOCK: %s - %d/%d", node.ID, locked, reqs)
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}
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} else if ext.State == AbortingLock {
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ext.Requirements[source] = Unlocking
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msgs = msgs.Add(ctx, node.ID, node.Key, NewLockSignal("unlock"), source)
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}
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}
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case "unlocked":
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state, found := ext.Requirements[source]
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if found == false {
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msgs = msgs.Add(ctx, node.ID, node.Key, NewErrorSignal(signal.ID, "not_requirement"), source)
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} else if state == Unlocking {
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ext.Requirements[source] = Unlocked
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reqs := 0
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unlocked := 0
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for _, s := range(ext.Requirements) {
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reqs += 1
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if s == Unlocked {
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unlocked += 1
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}
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}
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if unlocked == reqs {
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old_state := ext.State
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ext.State = Unlocked
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if old_state == Unlocking {
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ext.Owner = ext.PendingOwner
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ext.ReqID = nil
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msgs = msgs.Add(ctx, node.ID, node.Key, NewLockSignal("unlocked"), *ext.Owner)
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} else if old_state == AbortingLock {
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msgs = msgs.Add(ctx ,node.ID, node.Key, NewErrorSignal(*ext.ReqID, "not_unlocked"), *ext.PendingOwner)
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ext.PendingOwner = ext.Owner
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}
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} else {
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ctx.Log.Logf("lockable", "PARTIAL UNLOCK: %s - %d/%d", node.ID, unlocked, reqs)
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}
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}
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case "lock":
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if ext.State == Unlocked {
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if len(ext.Requirements) == 0 {
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ext.State = Locked
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new_owner := source
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ext.PendingOwner = &new_owner
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ext.Owner = &new_owner
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msgs = msgs.Add(ctx, node.ID, node.Key, NewLockSignal("locked"), new_owner)
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} else {
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ext.State = Locking
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id := signal.ID
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ext.ReqID = &id
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new_owner := source
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ext.PendingOwner = &new_owner
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for id, state := range(ext.Requirements) {
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if state != Unlocked {
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ctx.Log.Logf("lockable", "REQ_NOT_UNLOCKED_WHEN_LOCKING")
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}
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ext.Requirements[id] = Locking
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lock_signal := NewLockSignal("lock")
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msgs = msgs.Add(ctx, node.ID, node.Key, lock_signal, id)
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}
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}
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} else {
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msgs = msgs.Add(ctx, node.ID, node.Key, NewErrorSignal(signal.ID, "not_unlocked"), source)
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}
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case "unlock":
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if ext.State == Locked {
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if len(ext.Requirements) == 0 {
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ext.State = Unlocked
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new_owner := source
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ext.PendingOwner = nil
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ext.Owner = nil
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msgs = msgs.Add(ctx, node.ID, node.Key, NewLockSignal("unlocked"), new_owner)
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} else if source == *ext.Owner {
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ext.State = Unlocking
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id := signal.ID
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ext.ReqID = &id
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ext.PendingOwner = nil
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for id, state := range(ext.Requirements) {
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if state != Locked {
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ctx.Log.Logf("lockable", "REQ_NOT_LOCKED_WHEN_UNLOCKING")
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}
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ext.Requirements[id] = Unlocking
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lock_signal := NewLockSignal("unlock")
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msgs = msgs.Add(ctx, node.ID, node.Key, lock_signal, id)
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}
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}
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} else {
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msgs = msgs.Add(ctx, node.ID, node.Key, NewErrorSignal(signal.ID, "not_locked"), source)
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}
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default:
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ctx.Log.Logf("lockable", "LOCK_ERR: unkown state %s", signal.State)
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}
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return msgs
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}
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// LockableExts process Up/Down signals by forwarding them to owner, dependency, and requirement nodes
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// LockSignal and LinkSignal Direct signals are processed to update the requirement/dependency/lock state
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func (ext *LockableExt) Process(ctx *Context, node *Node, source NodeID, signal Signal) Messages {
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messages := Messages{}
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switch signal.Header().Direction {
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case Up:
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if ext.Owner != nil {
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if *ext.Owner != node.ID {
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messages = messages.Add(ctx, node.ID, node.Key, signal, *ext.Owner)
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}
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}
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case Down:
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for requirement, _ := range(ext.Requirements) {
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messages = messages.Add(ctx, node.ID, node.Key, signal, requirement)
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}
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case Direct:
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switch sig := signal.(type) {
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case *LinkSignal:
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messages = ext.HandleLinkSignal(ctx, node, source, sig)
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case *LockSignal:
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messages = ext.HandleLockSignal(ctx, node, source, sig)
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case *ErrorSignal:
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messages = ext.HandleErrorSignal(ctx, node, source, sig)
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default:
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}
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default:
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}
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return messages
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}
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