diff options
Diffstat (limited to 'phony')
| -rw-r--r-- | phony/LICENSE | 373 | ||||
| -rw-r--r-- | phony/README | 1 | ||||
| -rw-r--r-- | phony/actor.go | 139 | ||||
| -rw-r--r-- | phony/actor_test.go | 220 | ||||
| -rw-r--r-- | phony/doc.go | 7 |
5 files changed, 740 insertions, 0 deletions
diff --git a/phony/LICENSE b/phony/LICENSE new file mode 100644 index 0000000..a612ad9 --- /dev/null +++ b/phony/LICENSE @@ -0,0 +1,373 @@ +Mozilla Public License Version 2.0 +================================== + +1. Definitions +-------------- + +1.1. "Contributor" + means each individual or legal entity that creates, contributes to + the creation of, or owns Covered Software. + +1.2. "Contributor Version" + means the combination of the Contributions of others (if any) used + by a Contributor and that particular Contributor's Contribution. + +1.3. "Contribution" + means Covered Software of a particular Contributor. + +1.4. "Covered Software" + means Source Code Form to which the initial Contributor has attached + the notice in Exhibit A, the Executable Form of such Source Code + Form, and Modifications of such Source Code Form, in each case + including portions thereof. + +1.5. "Incompatible With Secondary Licenses" + means + + (a) that the initial Contributor has attached the notice described + in Exhibit B to the Covered Software; or + + (b) that the Covered Software was made available under the terms of + version 1.1 or earlier of the License, but not also under the + terms of a Secondary License. + +1.6. "Executable Form" + means any form of the work other than Source Code Form. + +1.7. "Larger Work" + means a work that combines Covered Software with other material, in + a separate file or files, that is not Covered Software. + +1.8. "License" + means this document. + +1.9. "Licensable" + means having the right to grant, to the maximum extent possible, + whether at the time of the initial grant or subsequently, any and + all of the rights conveyed by this License. + +1.10. "Modifications" + means any of the following: + + (a) any file in Source Code Form that results from an addition to, + deletion from, or modification of the contents of Covered + Software; or + + (b) any new file in Source Code Form that contains any Covered + Software. + +1.11. "Patent Claims" of a Contributor + means any patent claim(s), including without limitation, method, + process, and apparatus claims, in any patent Licensable by such + Contributor that would be infringed, but for the grant of the + License, by the making, using, selling, offering for sale, having + made, import, or transfer of either its Contributions or its + Contributor Version. + +1.12. "Secondary License" + means either the GNU General Public License, Version 2.0, the GNU + Lesser General Public License, Version 2.1, the GNU Affero General + Public License, Version 3.0, or any later versions of those + licenses. + +1.13. "Source Code Form" + means the form of the work preferred for making modifications. + +1.14. "You" (or "Your") + means an individual or a legal entity exercising rights under this + License. For legal entities, "You" includes any entity that + controls, is controlled by, or is under common control with You. For + purposes of this definition, "control" means (a) the power, direct + or indirect, to cause the direction or management of such entity, + whether by contract or otherwise, or (b) ownership of more than + fifty percent (50%) of the outstanding shares or beneficial + ownership of such entity. + +2. License Grants and Conditions +-------------------------------- + +2.1. Grants + +Each Contributor hereby grants You a world-wide, royalty-free, +non-exclusive license: + +(a) under intellectual property rights (other than patent or trademark) + Licensable by such Contributor to use, reproduce, make available, + modify, display, perform, distribute, and otherwise exploit its + Contributions, either on an unmodified basis, with Modifications, or + as part of a Larger Work; and + +(b) under Patent Claims of such Contributor to make, use, sell, offer + for sale, have made, import, and otherwise transfer either its + Contributions or its Contributor Version. + +2.2. Effective Date + +The licenses granted in Section 2.1 with respect to any Contribution +become effective for each Contribution on the date the Contributor first +distributes such Contribution. + +2.3. Limitations on Grant Scope + +The licenses granted in this Section 2 are the only rights granted under +this License. No additional rights or licenses will be implied from the +distribution or licensing of Covered Software under this License. +Notwithstanding Section 2.1(b) above, no patent license is granted by a +Contributor: + +(a) for any code that a Contributor has removed from Covered Software; + or + +(b) for infringements caused by: (i) Your and any other third party's + modifications of Covered Software, or (ii) the combination of its + Contributions with other software (except as part of its Contributor + Version); or + +(c) under Patent Claims infringed by Covered Software in the absence of + its Contributions. + +This License does not grant any rights in the trademarks, service marks, +or logos of any Contributor (except as may be necessary to comply with +the notice requirements in Section 3.4). + +2.4. Subsequent Licenses + +No Contributor makes additional grants as a result of Your choice to +distribute the Covered Software under a subsequent version of this +License (see Section 10.2) or under the terms of a Secondary License (if +permitted under the terms of Section 3.3). + +2.5. Representation + +Each Contributor represents that the Contributor believes its +Contributions are its original creation(s) or it has sufficient rights +to grant the rights to its Contributions conveyed by this License. + +2.6. Fair Use + +This License is not intended to limit any rights You have under +applicable copyright doctrines of fair use, fair dealing, or other +equivalents. + +2.7. Conditions + +Sections 3.1, 3.2, 3.3, and 3.4 are conditions of the licenses granted +in Section 2.1. + +3. Responsibilities +------------------- + +3.1. Distribution of Source Form + +All distribution of Covered Software in Source Code Form, including any +Modifications that You create or to which You contribute, must be under +the terms of this License. You must inform recipients that the Source +Code Form of the Covered Software is governed by the terms of this +License, and how they can obtain a copy of this License. You may not +attempt to alter or restrict the recipients' rights in the Source Code +Form. + +3.2. Distribution of Executable Form + +If You distribute Covered Software in Executable Form then: + +(a) such Covered Software must also be made available in Source Code + Form, as described in Section 3.1, and You must inform recipients of + the Executable Form how they can obtain a copy of such Source Code + Form by reasonable means in a timely manner, at a charge no more + than the cost of distribution to the recipient; and + +(b) You may distribute such Executable Form under the terms of this + License, or sublicense it under different terms, provided that the + license for the Executable Form does not attempt to limit or alter + the recipients' rights in the Source Code Form under this License. + +3.3. Distribution of a Larger Work + +You may create and distribute a Larger Work under terms of Your choice, +provided that You also comply with the requirements of this License for +the Covered Software. If the Larger Work is a combination of Covered +Software with a work governed by one or more Secondary Licenses, and the +Covered Software is not Incompatible With Secondary Licenses, this +License permits You to additionally distribute such Covered Software +under the terms of such Secondary License(s), so that the recipient of +the Larger Work may, at their option, further distribute the Covered +Software under the terms of either this License or such Secondary +License(s). + +3.4. Notices + +You may not remove or alter the substance of any license notices +(including copyright notices, patent notices, disclaimers of warranty, +or limitations of liability) contained within the Source Code Form of +the Covered Software, except that You may alter any license notices to +the extent required to remedy known factual inaccuracies. + +3.5. Application of Additional Terms + +You may choose to offer, and to charge a fee for, warranty, support, +indemnity or liability obligations to one or more recipients of Covered +Software. However, You may do so only on Your own behalf, and not on +behalf of any Contributor. You must make it absolutely clear that any +such warranty, support, indemnity, or liability obligation is offered by +You alone, and You hereby agree to indemnify every Contributor for any +liability incurred by such Contributor as a result of warranty, support, +indemnity or liability terms You offer. You may include additional +disclaimers of warranty and limitations of liability specific to any +jurisdiction. + +4. Inability to Comply Due to Statute or Regulation +--------------------------------------------------- + +If it is impossible for You to comply with any of the terms of this +License with respect to some or all of the Covered Software due to +statute, judicial order, or regulation then You must: (a) comply with +the terms of this License to the maximum extent possible; and (b) +describe the limitations and the code they affect. Such description must +be placed in a text file included with all distributions of the Covered +Software under this License. Except to the extent prohibited by statute +or regulation, such description must be sufficiently detailed for a +recipient of ordinary skill to be able to understand it. + +5. Termination +-------------- + +5.1. The rights granted under this License will terminate automatically +if You fail to comply with any of its terms. However, if You become +compliant, then the rights granted under this License from a particular +Contributor are reinstated (a) provisionally, unless and until such +Contributor explicitly and finally terminates Your grants, and (b) on an +ongoing basis, if such Contributor fails to notify You of the +non-compliance by some reasonable means prior to 60 days after You have +come back into compliance. Moreover, Your grants from a particular +Contributor are reinstated on an ongoing basis if such Contributor +notifies You of the non-compliance by some reasonable means, this is the +first time You have received notice of non-compliance with this License +from such Contributor, and You become compliant prior to 30 days after +Your receipt of the notice. + +5.2. If You initiate litigation against any entity by asserting a patent +infringement claim (excluding declaratory judgment actions, +counter-claims, and cross-claims) alleging that a Contributor Version +directly or indirectly infringes any patent, then the rights granted to +You by any and all Contributors for the Covered Software under Section +2.1 of this License shall terminate. + +5.3. In the event of termination under Sections 5.1 or 5.2 above, all +end user license agreements (excluding distributors and resellers) which +have been validly granted by You or Your distributors under this License +prior to termination shall survive termination. + +************************************************************************ +* * +* 6. Disclaimer of Warranty * +* ------------------------- * +* * +* Covered Software is provided under this License on an "as is" * +* basis, without warranty of any kind, either expressed, implied, or * +* statutory, including, without limitation, warranties that the * +* Covered Software is free of defects, merchantable, fit for a * +* particular purpose or non-infringing. The entire risk as to the * +* quality and performance of the Covered Software is with You. * +* Should any Covered Software prove defective in any respect, You * +* (not any Contributor) assume the cost of any necessary servicing, * +* repair, or correction. This disclaimer of warranty constitutes an * +* essential part of this License. No use of any Covered Software is * +* authorized under this License except under this disclaimer. * +* * +************************************************************************ + +************************************************************************ +* * +* 7. Limitation of Liability * +* -------------------------- * +* * +* Under no circumstances and under no legal theory, whether tort * +* (including negligence), contract, or otherwise, shall any * +* Contributor, or anyone who distributes Covered Software as * +* permitted above, be liable to You for any direct, indirect, * +* special, incidental, or consequential damages of any character * +* including, without limitation, damages for lost profits, loss of * +* goodwill, work stoppage, computer failure or malfunction, or any * +* and all other commercial damages or losses, even if such party * +* shall have been informed of the possibility of such damages. This * +* limitation of liability shall not apply to liability for death or * +* personal injury resulting from such party's negligence to the * +* extent applicable law prohibits such limitation. Some * +* jurisdictions do not allow the exclusion or limitation of * +* incidental or consequential damages, so this exclusion and * +* limitation may not apply to You. * +* * +************************************************************************ + +8. Litigation +------------- + +Any litigation relating to this License may be brought only in the +courts of a jurisdiction where the defendant maintains its principal +place of business and such litigation shall be governed by laws of that +jurisdiction, without reference to its conflict-of-law provisions. +Nothing in this Section shall prevent a party's ability to bring +cross-claims or counter-claims. + +9. Miscellaneous +---------------- + +This License represents the complete agreement concerning the subject +matter hereof. If any provision of this License is held to be +unenforceable, such provision shall be reformed only to the extent +necessary to make it enforceable. Any law or regulation which provides +that the language of a contract shall be construed against the drafter +shall not be used to construe this License against a Contributor. + +10. Versions of the License +--------------------------- + +10.1. New Versions + +Mozilla Foundation is the license steward. Except as provided in Section +10.3, no one other than the license steward has the right to modify or +publish new versions of this License. Each version will be given a +distinguishing version number. + +10.2. Effect of New Versions + +You may distribute the Covered Software under the terms of the version +of the License under which You originally received the Covered Software, +or under the terms of any subsequent version published by the license +steward. + +10.3. Modified Versions + +If you create software not governed by this License, and you want to +create a new license for such software, you may create and use a +modified version of this License if you rename the license and remove +any references to the name of the license steward (except to note that +such modified license differs from this License). + +10.4. Distributing Source Code Form that is Incompatible With Secondary +Licenses + +If You choose to distribute Source Code Form that is Incompatible With +Secondary Licenses under the terms of this version of the License, the +notice described in Exhibit B of this License must be attached. + +Exhibit A - Source Code Form License Notice +------------------------------------------- + + This Source Code Form is subject to the terms of the Mozilla Public + License, v. 2.0. If a copy of the MPL was not distributed with this + file, You can obtain one at http://mozilla.org/MPL/2.0/. + +If it is not possible or desirable to put the notice in a particular +file, then You may include the notice in a location (such as a LICENSE +file in a relevant directory) where a recipient would be likely to look +for such a notice. + +You may add additional accurate notices of copyright ownership. + +Exhibit B - "Incompatible With Secondary Licenses" Notice +--------------------------------------------------------- + + This Source Code Form is "Incompatible With Secondary Licenses", as + defined by the Mozilla Public License, v. 2.0. diff --git a/phony/README b/phony/README new file mode 100644 index 0000000..43ee8d8 --- /dev/null +++ b/phony/README @@ -0,0 +1 @@ +copied from https://github.com/Arceliar/phony diff --git a/phony/actor.go b/phony/actor.go new file mode 100644 index 0000000..2869e75 --- /dev/null +++ b/phony/actor.go @@ -0,0 +1,139 @@ +package phony + +import ( + "runtime" + "sync" + "sync/atomic" +) + +var stops = sync.Pool{New: func() interface{} { return make(chan struct{}, 1) }} +var elems = sync.Pool{New: func() interface{} { return new(queueElem) }} + +// A message in the queue +type queueElem struct { + msg func() + next atomic.Pointer[queueElem] // *queueElem, accessed atomically +} + +// Inbox is an ordered queue of messages which an Actor will process sequentially. +// Messages are meant to be in the form of non-blocking functions of 0 arguments, often closures. +// The intent is for the Inbox struct to be embedded in other structs, causing them to satisfy the Actor interface, and then the Actor is used to access any protected fields of the struct. +// It is up to the user to ensure that memory is used safely, and that messages do not contain blocking operations. +// An Inbox must not be copied after first use. +type Inbox struct { + noCopy noCopy + head *queueElem // Used carefully to avoid needing atomics + tail atomic.Pointer[queueElem] // *queueElem, accessed atomically + busy atomic.Bool // accessed atomically, 1 if sends should apply backpressure +} + +// Actor is the interface for Actors, based on their ability to receive a message from another Actor. +// It's meant so that structs which embed an Inbox can satisfy a mutually compatible interface for message passing. +type Actor interface { + Act(Actor, func()) + enqueue(func()) + restart() + advance() bool +} + +// enqueue puts a message into the Inbox and returns true if backpressure should be applied. +// If the inbox was empty, then the actor was not already running, so enqueue starts it. +func (a *Inbox) enqueue(msg func()) { + q := elems.Get().(*queueElem) + *q = queueElem{msg: msg} + tail := a.tail.Swap(q) + if tail != nil { + //An old tail exists, so update its next pointer to reference q + tail.next.Store(q) + } else { + // No old tail existed, so no worker is currently running + // Update the head to point to q, then start the worker + a.head = q + a.restart() + } +} + +// Act adds a message to an Inbox, which will be executed by the inbox's Actor at some point in the future. +// When one Actor sends a message to another, the sender is meant to provide itself as the first argument to this function. +// If the sender argument is non-nil and the receiving Inbox has been flooded, then backpressure is applied to the sender. +// This backpressue cause the sender stop processing messages at some point in the future until the receiver has caught up with the sent message. +// A nil first argument is valid, but should only be used in cases where backpressure is known to be unnecessary, such as when an Actor sends a message to itself or sends a response to a request (where it's the request sender's fault if they're flooded by responses). +func (a *Inbox) Act(from Actor, action func()) { + if action == nil { + panic("tried to send nil action") + } + a.enqueue(action) + if from != nil && a.busy.Load() { + done := stops.Get().(chan struct{}) + a.enqueue(func() { done <- struct{}{} }) + from.enqueue(func() { + <-done + stops.Put(done) + }) + } +} + +// Block adds a message to an Actor's Inbox, which will be executed at some point in the future. +// It then blocks until the Actor has finished running the provided function. +// Block meant exclusively as a convenience function for non-Actor code to send messages and wait for responses. +// If an Actor calls Block, then it may cause a deadlock, so Act should always be used instead. +func Block(actor Actor, action func()) { + if actor == nil { + panic("tried to send to nil actor") + } else if action == nil { + panic("tried to send nil action") + } + done := stops.Get().(chan struct{}) + actor.enqueue(action) + actor.enqueue(func() { done <- struct{}{} }) + <-done + stops.Put(done) +} + +// run is executed when a message is placed in an empty Inbox, and launches a worker goroutine. +// The worker goroutine processes messages from the Inbox until empty, and then exits. +func (a *Inbox) run() { + a.busy.Store(true) + for running := true; running; running = a.advance() { + a.head.msg() + } +} + +// returns true if we still have more work to do +func (a *Inbox) advance() (more bool) { + head := a.head + a.head = head.next.Load() + if a.head == nil { + // We loaded the last message + // Unset busy and CAS the tail to nil to shut down + a.busy.Store(false) + if !a.tail.CompareAndSwap(head, nil) { + // Someone pushed to the list before we could CAS the tail to shut down + // This means we're effectively restarting at this point + // Set busy and load the next message + a.busy.Store(true) + for a.head == nil { + // Busy loop until the message is successfully loaded + // Gosched to avoid blocking the thread in the mean time + runtime.Gosched() + a.head = head.next.Load() + } + more = true + } + } else { + more = true + } + *head = queueElem{} + elems.Put(head) + return +} + +func (a *Inbox) restart() { + go a.run() +} + +// noCopy implements the sync.Locker interface, so go vet can catch unsafe copying +type noCopy struct{} + +func (n *noCopy) Lock() {} +func (n *noCopy) Unlock() {} diff --git a/phony/actor_test.go b/phony/actor_test.go new file mode 100644 index 0000000..68e91d1 --- /dev/null +++ b/phony/actor_test.go @@ -0,0 +1,220 @@ +package phony + +import ( + "testing" + "unsafe" +) + +func TestInboxSize(t *testing.T) { + var a Inbox + var q queueElem + t.Logf("Inbox size: %d, message size: %d", unsafe.Sizeof(a), unsafe.Sizeof(q)) +} + +func TestBlock(t *testing.T) { + var a Inbox + var results []int + for idx := 0; idx < 1024; idx++ { + n := idx // Because idx gets mutated in place + Block(&a, func() { + results = append(results, n) + }) + } + for idx, n := range results { + if n != idx { + t.Errorf("value %d != index %d", n, idx) + } + } +} + +func TestAct(t *testing.T) { + var a Inbox + var results []int + Block(&a, func() { + for idx := 0; idx < 1024; idx++ { + n := idx // Because idx gets mutated in place + a.Act(&a, func() { + results = append(results, n) + }) + } + }) + Block(&a, func() {}) + for idx, n := range results { + if n != idx { + t.Errorf("value %d != index %d", n, idx) + } + } +} + +func TestPanicAct(t *testing.T) { + defer func() { + if r := recover(); r == nil { + t.Errorf("The code did not panic") + } + }() + var a Inbox + a.Act(nil, nil) +} + +func TestPanicBlockActor(t *testing.T) { + defer func() { + if r := recover(); r == nil { + t.Errorf("The code did not panic") + } + }() + Block(nil, nil) +} + +func TestPanicBlockAction(t *testing.T) { + defer func() { + if r := recover(); r == nil { + t.Errorf("The code did not panic") + } + }() + var a Inbox + Block(&a, nil) +} + +func BenchmarkLoopActor(b *testing.B) { + var a Inbox + done := make(chan struct{}) + idx := 0 + var f func() + f = func() { + if idx < b.N { + idx++ + a.Act(nil, f) + } else { + close(done) + } + } + a.Act(nil, f) + <-done +} + +func BenchmarkLoopChannel(b *testing.B) { + ch := make(chan func(), 1) + defer close(ch) + go func() { + for f := range ch { + f() + } + }() + done := make(chan struct{}) + idx := 0 + var f func() + f = func() { + if idx < b.N { + idx++ + ch <- f + } else { + close(done) + } + } + ch <- f + <-done +} + +func BenchmarkSendActor(b *testing.B) { + var a, s Inbox + done := make(chan struct{}) + idx := 0 + var f func() + f = func() { + if idx < b.N { + idx++ + a.Act(&s, func() {}) + s.Act(nil, f) + } else { + a.Act(&s, func() { close(done) }) + } + } + s.Act(nil, f) + <-done +} + +func BenchmarkSendChannel(b *testing.B) { + done := make(chan struct{}) + ch := make(chan func()) + go func() { + for f := range ch { + f() + } + close(done) + }() + f := func() {} + for i := 0; i < b.N; i++ { + ch <- f + } + close(ch) + <-done +} + +func BenchmarkRequestResponseActor(b *testing.B) { + var pinger, ponger Inbox + done := make(chan struct{}) + idx := 0 + var ping, pong func() + ping = func() { + if idx < b.N { + idx++ + ponger.Act(&pinger, pong) + pinger.Act(nil, ping) // loop asynchronously + } else { + ponger.Act(&pinger, func() { + pinger.Act(nil, func() { + close(done) + }) + }) + } + } + pong = func() { + pinger.Act(nil, func() {}) // send a response without backpressure + } + pinger.Act(nil, ping) + <-done +} + +func BenchmarkRequestResponseChannel(b *testing.B) { + done := make(chan struct{}) + toPing := make(chan func(), 1) + toPong := make(chan func(), 1) + defer close(toPing) + defer close(toPong) + var ping func() + var pong func() + ping = func() { + for idx := 0; idx < b.N; idx++ { + toPong <- pong + f := <-toPing + f() + } + toPong <- func() { + toPing <- func() { + close(done) + } + } + } + pong = func() { + toPing <- func() {} + } + go func() { + for f := range toPing { + f() + } + }() + go func() { + for f := range toPong { + f() + } + }() + toPing <- ping + <-done +} + +func BenchmarkBlock(b *testing.B) { + var a Inbox + for i := 0; i < b.N; i++ { + Block(&a, func() {}) + } +} diff --git a/phony/doc.go b/phony/doc.go new file mode 100644 index 0000000..554cc80 --- /dev/null +++ b/phony/doc.go @@ -0,0 +1,7 @@ +// Package phony is a small actor model library for Go, inspired by the causal messaging system in the Pony programming language. +// An Actor is an interface satisfied by a lightweight Inbox struct. +// Structs that embed an Inbox satisfy an interface that allows them to send messages to eachother. +// Messages are functions of 0 arguments, typically closures, and should not perform blocking operations. +// Message passing is asynchronous, causal, and fast. +// Actors implemented by the provided Inbox struct are scheduled to prevent messages queues from growing too large, by pausing at safe breakpoints when an Actor detects that it sent something to another Actor whose inbox is flooded. +package phony |