From 4e5b98af4cf902627061f67c589bf7b105743828 Mon Sep 17 00:00:00 2001
From: masterex1000 <conradcol6@gmail.com>
Date: Wed, 26 Sep 2018 17:47:01 -0600
Subject: [PATCH] Add les.js (Memory Evict)

---
 lib/les.js | 121 +++++++++++++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 121 insertions(+)
 create mode 100644 lib/les.js

diff --git a/lib/les.js b/lib/les.js
new file mode 100644
index 00000000..e6f3cb16
--- /dev/null
+++ b/lib/les.js
@@ -0,0 +1,121 @@
+;
+(function() {
+
+	//  _     _____ ____    _     
+	// | |   | ____/ ___|  (_)___ 
+	// | |   |  _| \___ \  | / __|
+	// | |___| |___ ___) | | \__ \
+	// |_____|_____|____(_)/ |___/
+	// ----------------------------
+	// LES.js (Last rEcently uSed)
+	// ----------------------------
+	// A Small, lightweight, queue-based
+	// Garbage Collector for Gun
+	// Originally By: Collin Conrad (@masterex1000)
+
+	//NOTE: set to false is running from file in YOUR code
+	var USELOCALGUN = true; 
+	
+	//NOTE: adds some debug messages
+	var DEBUG = false;
+	
+	
+	var Gun = (typeof window !== "undefined") ? window.Gun : (USELOCALGUN ? require('../gun') : require("gun"));
+	var ev = {};
+	var empty = {};
+
+	Gun.on('opt', function(root) {
+		this.to.next(root);
+		if (root.once)
+			return;
+		if (typeof process == 'undefined')
+			return
+		var mem = process.memoryUsage;
+
+		if (!mem) //exit because we are in the browser
+			return;
+
+		//Figure out the most amount of memory we can use. TODO: make configurable?
+		ev.max = parseFloat(root.opt.memory || process.env.WEB_MEMORY || 512) * 0.8;
+
+		var nodes = {}; //checks if the node already exists
+		var nodesArray = []; //used to easily sort everything and store info about the nodes
+		var memoryUpdate = 0; // last time we printed the current memory stats
+
+		var check = function() {
+			ev.used = mem().rss / 1024 / 1024; //Contains the amt. of used ram in MB
+			setTimeout(function() { // So we can handle requests etc. before we start collecting
+				GC(ev.used / ev.max); // Calculate the memory ratio, and execute the garbage collector
+			}, 1);
+		}
+		
+		setInterval(check, 1000); // set the garbage collector to run every second, TODO: make configurable
+		
+		//Executed every time a node gets modifyed
+		root.on("put", function(e) {
+			var ctime = Date.now();
+			var souls = Object.keys(e.put || empty);
+			for (var i = 0; i < souls.length; i++) {
+				enqueueNode(souls[i], ctime);
+			}
+		});
+
+		//Adds a soul the garbage collectors "freeing" queue
+		function enqueueNode(soul, ctime) {
+			if (nodes[soul] == true) { //The node already exists in the queue
+				var index = nodesArray.findIndex(function(e) {
+					return e[0] === soul;
+				});
+				if (index == -1) {
+					console.err("Something happened and the node '" + soul + "' won't get garbage collection unless the value is updated agian");
+					return;
+				} else {
+					nodesArray.splice(index, 1); // remove the existing ref.
+					nodesArray.push([soul, ctime]); // push the new instance
+				}
+			} else {
+				nodesArray.push([soul, ctime]);
+				nodes[soul] = true;
+			}
+		}
+
+		//The main garbage collecting routine
+		function GC(memRatio) {
+			var curTime = Date.now(); // get the current time
+
+			if (curTime - memoryUpdate >= 5000) {
+				console.log("|GC| %s | Current Memory Ratio: %d | Current Ram Usage %sMB | Nodes in Memory %s", new Date().toLocaleString(), round(memRatio, 2), round(ev.used, 2), Object.keys(root.graph || empty).length);
+				memoryUpdate = curTime;
+			}
+
+			var freed = 0;
+
+			while (nodesArray.length > 0) {
+				var soul = nodesArray[0][0];
+				var nts = nodesArray[0][1];
+				if (DEBUG)
+					console.log("Soul: " + soul + " | Remove Importance: " + calcRemoveImportance(nts, curTime, memRatio) +
+						" | Memory Ratio: " + memRatio + " | Time Existed: " + (curTime - nts) / 1000);
+				if (calcRemoveImportance(nodesArray[0][1], curTime, memRatio) >= 100) {
+					root.gun.get(nodesArray[0][0]).off(); //Remove the node
+					delete nodes[nodesArray[0][0]]; // remove the lookup value
+					nodesArray.splice(0, 1);
+					freed++;
+				} else
+					break;
+			}
+			if (freed > 0)
+				console.log("|GC| Removed %s nodes in %s seconds-----------------------------------------------------------------", freed, (Date.now() - curTime) * 0.001);
+		}
+
+		//Generates a number that, after it hits a threshold, the node gets removed
+		function calcRemoveImportance(timestamp, ctime, memoryUsageRatio) {
+			var time = (ctime - timestamp) * 0.001;
+			return time * 10 * (memoryUsageRatio * memoryUsageRatio)
+		}
+
+		function round(value, decimals) { //a basic rounding function
+			return Number(Math.round(value + 'e' + decimals) + 'e-' + decimals);
+		}
+	});
+}());
\ No newline at end of file