File: //home/arjun/.pm2/modules/pm2-logrotate/node_modules/pmx/lib/utils/fixedQueue.js
function FixedQueue( size, initialValues ){
// If there are no initial arguments, default it to
// an empty value so we can call the constructor in
// a uniform way.
initialValues = (initialValues || []);
// Create the fixed queue array value.
var queue = Array.apply( null, initialValues );
// Store the fixed size in the queue.
queue.fixedSize = size;
// Add the class methods to the queue. Some of these have
// to override the native Array methods in order to make
// sure the queue lenght is maintained.
queue.push = FixedQueue.push;
queue.splice = FixedQueue.splice;
queue.unshift = FixedQueue.unshift;
// Trim any initial excess from the queue.
FixedQueue.trimTail.call( queue );
// Return the new queue.
return( queue );
}
// I trim the queue down to the appropriate size, removing
// items from the beginning of the internal array.
FixedQueue.trimHead = function(){
// Check to see if any trimming needs to be performed.
if (this.length <= this.fixedSize){
// No trimming, return out.
return;
}
// Trim whatever is beyond the fixed size.
Array.prototype.splice.call(
this,
0,
(this.length - this.fixedSize)
);
};
// I trim the queue down to the appropriate size, removing
// items from the end of the internal array.
FixedQueue.trimTail = function(){
// Check to see if any trimming needs to be performed.
if (this.length <= this.fixedSize){
// No trimming, return out.
return;
}
// Trim whatever is beyond the fixed size.
Array.prototype.splice.call(
this,
this.fixedSize,
(this.length - this.fixedSize)
);
};
// I synthesize wrapper methods that call the native Array
// methods followed by a trimming method.
FixedQueue.wrapMethod = function( methodName, trimMethod ){
// Create a wrapper that calls the given method.
var wrapper = function(){
// Get the native Array method.
var method = Array.prototype[ methodName ];
// Call the native method first.
var result = method.apply( this, arguments );
// Trim the queue now that it's been augmented.
trimMethod.call( this );
// Return the original value.
return( result );
};
// Return the wrapper method.
return( wrapper );
};
// Wrap the native methods.
FixedQueue.push = FixedQueue.wrapMethod(
"push",
FixedQueue.trimHead
);
FixedQueue.splice = FixedQueue.wrapMethod(
"splice",
FixedQueue.trimTail
);
FixedQueue.unshift = FixedQueue.wrapMethod(
"unshift",
FixedQueue.trimTail
);