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Migrate from libsnooze (#8)
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* Dub

- Removed `libsnooze` dependency

* Queue

- Removed `libsnooze` imports

* Queue

- Added mutex+condition variable

* Queue

- Removed old `ensure()` call

* Queue

- Switched one thing over to mutex+condvar

* Queue

- Switched to using condition variable
- Added configurable slumber interval
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deavmi authored Oct 1, 2023
1 parent 761ddb2 commit 42c6b11
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Showing 2 changed files with 67 additions and 53 deletions.
3 changes: 1 addition & 2 deletions dub.json
Original file line number Diff line number Diff line change
Expand Up @@ -4,8 +4,7 @@
],
"copyright": "Copyright © 2023, Tristan B. Kildaire",
"dependencies": {
"bformat": ">=4.1.1",
"libsnooze": ">=1.3.0-beta"
"bformat": ">=4.1.1"
},
"description": "Tristanable network message queuing framework",
"homepage": "https://deavmi.assigned.network/projects/tristanable",
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117 changes: 66 additions & 51 deletions source/tristanable/queue.d
Original file line number Diff line number Diff line change
Expand Up @@ -3,14 +3,12 @@
*/
module tristanable.queue;

// TODO: Examine the below import which seemingly fixes stuff for libsnooze
import libsnooze.clib;
import libsnooze;

import core.sync.mutex : Mutex;
import core.sync.condition : Condition;
import core.sync.exception : SyncError;
import std.container.slist : SList;
import tristanable.encoding;
import core.thread : dur;
import core.time : Duration, dur;
import tristanable.exceptions;

version(unittest)
Expand All @@ -27,10 +25,15 @@ version(unittest)
public class Queue
{
/**
* The libsnooze event used to sleep/wake
* on queue events
* Mutex for the condition variable
*/
private Mutex mutex;

/**
* The condition variable used to sleep/wake
* on queue of events
*/
private Event event;
private Condition signal;

/**
* The queue of messages
Expand All @@ -47,6 +50,15 @@ public class Queue
*/
private ulong queueID;

/**
* If a message is enqueued prior
* to us sleeping then we won't
* wake up and return for it.
*
* Therefore a periodic wakeup
* is required.
*/
private Duration wakeInterval;

/**
* Constructs a new Queue and immediately sets up the notification
Expand All @@ -62,14 +74,37 @@ public class Queue
/* Initialize the queue lock */
this.queueLock = new Mutex();

/* Initialize the event */
this.event = new Event();
/* Initialize the condition variable */
this.mutex = new Mutex();
this.signal = new Condition(this.mutex);

/* Set the queue id */
this.queueID = queueID;

/* Ensure pipe existence (see https://deavmi.assigned.network/git/deavmi/tristanable/issues/5) */
event.wait(dur!("seconds")(0));
/* Set the slumber interval */
this.wakeInterval = dur!("msecs")(50); // TODO: Decide on value
}

/**
* Returns the current wake interval
* for the queue checker
*
* Returns: the `Duration`
*/
public Duration getWakeInterval()
{
return this.wakeInterval;
}

/**
* Sets the wake up interval
*
* Params:
* interval = the new interval
*/
public void setWakeInterval(Duration interval)
{
this.wakeInterval = interval;
}

/**
Expand Down Expand Up @@ -111,9 +146,9 @@ public class Queue
try
{
// TODO: Make us wait on the event (optional with a time-out)
event.notifyAll();
signal.notifyAll();
}
catch(FatalException snozErr)
catch(SyncError snozErr)
{
// Throw an exception on a fatal exception
throw new TristanableException(ErrorType.ENQUEUE_FAILED);
Expand Down Expand Up @@ -151,45 +186,25 @@ public class Queue
/* Block till we dequeue a message successfully */
while(dequeuedMessage is null)
{
/**
* Call `wait()` and catch any interrupts
* in which case loop back and call `wait()`
* again
*/
while(true)
scope(exit)
{
try
{
// TODO: Make us wait on the event (optional with a time-out)
event.wait();
}
catch(InterruptedException e)
{
version(unittest)
{
import std.stdio;
writeln("dequeue() had libsnooze wait() get interrupted!");
}

// Retry the wait()
continue;
}
catch(FatalException fatalErr)
{
version(unittest)
{
import std.stdio;
writeln("dequeue() had libsnooze wait() get FATALLY fail! Exception will now throw...");
}

// Throw an exception on a fatal exception
throw new TristanableException(ErrorType.DEQUEUE_FAILED);
}

// On successful wait() wake-up exit this wait()-retry loop
break;
// Unlock the mutex
this.mutex.unlock();
}


// Lock the mutex
this.mutex.lock();

try
{
this.signal.wait(this.wakeInterval);
}
catch(SyncError e)
{
// Throw an exception on a fatal exception
throw new TristanableException(ErrorType.DEQUEUE_FAILED);
}


/* Lock the item queue */
queueLock.lock();
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