gun/src/get.js

A realtime, decentralized, offline-first, graph data synchronization engine.

var Gun = require('./root');
Gun.chain.get = function(key, cb, as){
	var gun, tmp;
	if(typeof key === 'string'){
		if(key.length == 0) {	
			(gun = this.chain())._.err = {err: Gun.log('0 length key!', key)};
			if(cb){ cb.call(gun, gun._.err) }
			return gun;
		}
		var back = this, cat = back._;
		var next = cat.next || empty;
		if(!(gun = next[key])){
			gun = key && cache(key, back);
		}
		gun = gun && gun.$;
	} else
	if('function' == typeof key){
		if(true === cb){ return soul(this, key, cb, as), this }
		gun = this;
		var cat = gun._, opt = cb || {}, root = cat.root, id;
		opt.at = cat;
		opt.ok = key;
		var wait = {}; // can we assign this to the at instead, like in once?
		//var path = []; cat.$.back(at => { at.get && path.push(at.get.slice(0,9))}); path = path.reverse().join('.');
		function any(msg, eve, f){
			if(any.stun){ return }
			if((tmp = root.pass) && !tmp[id]){ return }
			var at = msg.$._, sat = (msg.$$||'')._, data = (sat||at).put, odd = (!at.has && !at.soul), test = {}, link, tmp;
			if(odd || u === data){ // handles non-core
				data = (u === ((tmp = msg.put)||'')['='])? (u === (tmp||'')[':'])? tmp : tmp[':'] : tmp['='];
			}
			if(link = ('string' == typeof (tmp = Gun.valid(data)))){
				data = (u === (tmp = root.$.get(tmp)._.put))? opt.not? u : data : tmp;
			}
			if(opt.not && u === data){ return }
			if(u === opt.stun){
				if((tmp = root.stun) && tmp.on){
					cat.$.back(function(a){ // our chain stunned?
						tmp.on(''+a.id, test = {});
						if((test.run || 0) < any.id){ return test } // if there is an earlier stun on gapless parents/self.
					});
					!test.run && tmp.on(''+at.id, test = {}); // this node stunned?
					!test.run && sat && tmp.on(''+sat.id, test = {}); // linked node stunned?
					if(any.id > test.run){
						if(!test.stun || test.stun.end){
							test.stun = tmp.on('stun');
							test.stun = test.stun && test.stun.last;
						}
						if(test.stun && !test.stun.end){
							//if(odd && u === data){ return }
							//if(u === msg.put){ return } // "not found" acks will be found if there is stun, so ignore these.
							(test.stun.add || (test.stun.add = {}))[id] = function(){ any(msg,eve,1) } // add ourself to the stun callback list that is called at end of the write.
							return;
						}
					}
				}
				if(/*odd &&*/ u === data){ f = 0 } // if data not found, keep waiting/trying.
				/*if(f && u === data){
					cat.on('out', opt.out);
					return;
				}*/
				if((tmp = root.hatch) && !tmp.end && u === opt.hatch && !f){ // quick hack! // What's going on here? Because data is streamed, we get things one by one, but a lot of developers would rather get a callback after each batch instead, so this does that by creating a wait list per chain id that is then called at the end of the batch by the hatch code in the root put listener.
					if(wait[at.$._.id]){ return } wait[at.$._.id] = 1;
					tmp.push(function(){any(msg,eve,1)});
					return;
				}; wait = {}; // end quick hack.
			}
			// call:
			if(root.pass){ if(root.pass[id+at.id]){ return } root.pass[id+at.id] = 1 }
			if(opt.on){ opt.ok.call(at.$, data, at.get, msg, eve || any); return } // TODO: Also consider breaking `this` since a lot of people do `=>` these days and `.call(` has slower performance.
			if(opt.v2020){ opt.ok(msg, eve || any); return }
			Object.keys(msg).forEach(function(k){ tmp[k] = msg[k] }, tmp = {}); msg = tmp; msg.put = data; // 2019 COMPATIBILITY! TODO: GET RID OF THIS!
			opt.ok.call(opt.as, msg, eve || any); // is this the right
		};
		any.at = cat;
		//(cat.any||(cat.any=function(msg){ setTimeout.each(Object.keys(cat.any||''), function(act){ (act = cat.any[act]) && act(msg) },0,99) }))[id = String.random(7)] = any; // maybe switch to this in future?
		(cat.any||(cat.any={}))[id = String.random(7)] = any;
		any.off = function(){ any.stun = 1; if(!cat.any){ return } delete cat.any[id] }
		any.rid = rid; // logic from old version, can we clean it up now?
		any.id = opt.run || ++root.once; // used in callback to check if we are earlier than a write. // will this ever cause an integer overflow?
		tmp = root.pass; (root.pass = {})[id] = 1; // Explanation: test trade-offs want to prevent recursion so we add/remove pass flag as it gets fulfilled to not repeat, however map map needs many pass flags - how do we reconcile?
		opt.out = opt.out || {get: {}};
		cat.on('out', opt.out);
		root.pass = tmp;
		return gun;
	} else
	if('number' == typeof key){
		return this.get(''+key, cb, as);
	} else
	if('string' == typeof (tmp = valid(key))){
		return this.get(tmp, cb, as);
	} else
	if(tmp = this.get.next){
		gun = tmp(this, key);
	}
	if(!gun){
		(gun = this.chain())._.err = {err: Gun.log('Invalid get request!', key)}; // CLEAN UP
		if(cb){ cb.call(gun, gun._.err) }
		return gun;
	}
	if(cb && 'function' == typeof cb){
		gun.get(cb, as);
	}
	return gun;
}
function cache(key, back){
	var cat = back._, next = cat.next, gun = back.chain(), at = gun._;
	if(!next){ next = cat.next = {} }
	next[at.get = key] = at;
	if(back === cat.root.$){
		at.soul = key;
		//at.put = {};
	} else
	if(cat.soul || cat.has){
		at.has = key;
		//if(obj_has(cat.put, key)){
			//at.put = cat.put[key];
		//}
	}
	return at;
}
function soul(gun, cb, opt, as){
	var cat = gun._, acks = 0, tmp;
	if(tmp = cat.soul || cat.link){ return cb(tmp, as, cat) }
	if(cat.jam){ return cat.jam.push([cb, as]) }
	cat.jam = [[cb,as]];
	gun.get(function go(msg, eve){
		if(u === msg.put && !cat.root.opt.super && (tmp = Object.keys(cat.root.opt.peers).length) && ++acks <= tmp){ // TODO: super should not be in core code, bring AXE up into core instead to fix? // TODO: .keys( is slow
			return;
		}
		eve.rid(msg);
		var at = ((at = msg.$) && at._) || {}, i = 0, as;
		tmp = cat.jam; delete cat.jam; // tmp = cat.jam.splice(0, 100);
		//if(tmp.length){ process.nextTick(function(){ go(msg, eve) }) }
		while(as = tmp[i++]){ //Gun.obj.map(tmp, function(as, cb){
			var cb = as[0], id; as = as[1];
			cb && cb(id = at.link || at.soul || Gun.valid(msg.put) || ((msg.put||{})._||{})['#'], as, msg, eve);
		} //);
	}, {out: {get: {'.':true}}});
	return gun;
}
function rid(at){
	var cat = this.at || this.on;
	if(!at || cat.soul || cat.has){ return this.off() }
	if(!(at = (at = (at = at.$ || at)._ || at).id)){ return }
	var map = cat.map, tmp, seen;
	//if(!map || !(tmp = map[at]) || !(tmp = tmp.at)){ return }
	if(tmp = (seen = this.seen || (this.seen = {}))[at]){ return true }
	seen[at] = true;
	return;
	//tmp.echo[cat.id] = {}; // TODO: Warning: This unsubscribes ALL of this chain's listeners from this link, not just the one callback event.
	//obj.del(map, at); // TODO: Warning: This unsubscribes ALL of this chain's listeners from this link, not just the one callback event.
	return;
}
var empty = {}, valid = Gun.valid, u;