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Use a tiny function to tack tiny UUID's to end of LocalStorage keys instead of a seperate indexer #185

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Use a tiny function to tack tiny UUID's to end of LocalStorage keys instead of a seperate indexer #185

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252 changes: 172 additions & 80 deletions src/adapters/dom.js
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Original file line number Diff line number Diff line change
Expand Up @@ -11,44 +11,97 @@
//
Lawnchair.adapter('dom', (function() {
var storage = window.localStorage
// the indexer is an encapsulation of the helpers needed to keep an ordered index of the keys
var indexer = function(name) {
return {
// the key
key: name + '._index_',
// returns the index
all: function() {
var a = storage.getItem(JSON.stringify(this.key))
if (a) {
a = JSON.parse(a)
}
if (a === null) storage.setItem(JSON.stringify(this.key), JSON.stringify([])) // lazy init
return JSON.parse(storage.getItem(JSON.stringify(this.key)))
},
// adds a key to the index
add: function (key) {
var a = this.all()
a.push(key)
storage.setItem(JSON.stringify(this.key), JSON.stringify(a))
},
// deletes a key from the index
del: function (key) {
var a = this.all(), r = []
// FIXME this is crazy inefficient but I'm in a strata meeting and half concentrating
for (var i = 0, l = a.length; i < l; i++) {
if (a[i] != key) r.push(a[i])
}
storage.setItem(JSON.stringify(this.key), JSON.stringify(r))
},
// returns index for a key
find: function (key) {
var a = this.all()
for (var i = 0, l = a.length; i < l; i++) {
if (key === a[i]) return i

// Generates (quite) small incremental UUID's which are tacked onto the end
// of LocalStorage keys to remove the requirement for a seperate indexer.
//
// NOTE: Taken from https://github.com/forbesmyester/SyncIt, Could be used
// for Lawnchair.uuid()
var getTLIdEncoderDecoder = function(epoch,uniqueLength) {

var lastDate = null;
var index = -1;
if (uniqueLength === undefined) {
uniqueLength = 1;
}

if (typeof epoch != 'number') {
throw "Only takes timestamps";
}

var genUid = function(now) {

if (now === undefined) {
now = new Date().getTime();
}
if (typeof now == 'object') {
throw "Only takes timestamps";
}

if ((lastDate === null) || (now !== lastDate)) {
index = -1;
}

var superUnique = (++index).toString(32);
if (superUnique.length < uniqueLength) {
superUnique = '0' + superUnique;
}
var timeEncoded = (now - epoch).toString(32);

if (superUnique.length > uniqueLength) {
throw "getUidGenerator.genUid cannot generate TLId until next millisecond!";
}

lastDate = now;
if (timeEncoded.substr(0,1) <= '9') {
return "X"+timeEncoded+superUnique;
}
return timeEncoded+superUnique;
};

var uidToTimestamp = function(tlid) {
if (tlid.substr(0,1) == 'X') {
tlid = tlid.substr(1);
}
tlid = tlid.substr(0, tlid.length - uniqueLength);
return parseInt(tlid,32) + epoch;
};

var sort = function(tlidA, tlidB) {
if (tlidA.substr(0,1) == 'X') {
tlidA = tlidA.substr(1);
}
if (tlidB.substr(0,1) == 'X') {
tlidB = tlidB.substr(1);
}
tlidA = tlidA.replace(/.*\./,'');
tlidB = tlidB.replace(/.*\./,'');
if (tlidA.length != tlidB.length) {
return (tlidA.length < tlidB.length) ? -1 : 1;
}
return (tlidA < tlidB) ? -1 : 1;
};

return {encode: genUid, decode: uidToTimestamp, sort: sort};
};

var keyCollector = function(inst, searchKey) {
var keys = [];
var key;
var subKey;
for (var i = 0, l = storage.length; i<l; i++) {
key = storage.key(i);
if (key.substring(0, inst.name.length + 1) == inst.name + ".") {
if (
(searchKey === undefined) ||
(key.substring(inst.name.length + 1).replace(/\.[^\.]+$/,'') == searchKey)
) {
keys.push(key.substring(inst.name.length + 1));
}
return false
}
}
keys.sort(inst.indexer.sort);
return keys;
}

// adapter api
Expand All @@ -72,18 +125,29 @@ Lawnchair.adapter('dom', (function() {
},

init: function (options, callback) {
this.indexer = indexer(this.name)
this.indexer = getTLIdEncoderDecoder(new Date(2013,9,19).getTime());
if (callback) this.fn(this.name, callback).call(this, this)
},

save: function (obj, callback) {
var key = obj.key ? this.name + '.' + obj.key : this.name + '.' + this.uuid()
// now we kil the key and use it in the store colleciton
var key;
// Calculate key in localStorage
if (obj.key) {
key = keyCollector(this, obj.key);
if (key.length) {
key = this.name + '.' + key[0];
} else {
key = this.name + '.' + obj.key + '.' + this.indexer.encode();
}
} else {
key = this.name + '.' + this.uuid() +'.' + this.indexer.encode();
}

// now we kil the key and use it in the store colleciton
delete obj.key;
storage.setItem(key, JSON.stringify(obj))
// if the key is not in the index push it on
if (this.indexer.find(key) === false) this.indexer.add(key)
obj.key = key.slice(this.name.length + 1)
obj.key = key.slice(this.name.length + 1).replace(/\.[^.]+$/,'');
if (callback) {
this.lambda(callback).call(this, obj)
}
Expand All @@ -101,69 +165,96 @@ Lawnchair.adapter('dom', (function() {
if (callback) this.lambda(callback).call(this, saved)
return this
},

// accepts [options], callback
keys: function(callback) {

var replaceFunc = function(r){
return r.replace(/\.[^\.]+$/,'')
};

var keys = [];

if (callback) {
var name = this.name
var indices = this.indexer.all();
var keys = [];
//Checking for the support of map.
if(Array.prototype.map) {
keys = indices.map(function(r){ return r.replace(name + '.', '') })
keys = keyCollector(this).map(replaceFunc)
} else {
for (var key in indices) {
keys.push(key.replace(name + '.', ''));
var indices = keyCollector(this);
for (var i = 0, l = indices.length; i < l; i++) {
keys.push(replaceFunc(indices[i]));
}
}

this.fn('keys', callback).call(this, keys)
}
return this // TODO options for limit/offset, return promise
},

get: function (key, callback) {

var getRealKeyObj = function(realKey) {
var r = {};
for (var i = 0, l = realKey.length; i < l; i++) {
r[realKey[i].replace(/\.[^\.]+$/,'')] = realKey[i].replace(/.*\./,'');
}
return r;
}

var obj = null,
realKeyObj,
realKey;

if (this.isArray(key)) {
realKeyObj = getRealKeyObj(keyCollector(this));

var r = []
for (var i = 0, l = key.length; i < l; i++) {
var k = this.name + '.' + key[i]
var obj = storage.getItem(k)
if (obj) {
obj = JSON.parse(obj)
obj.key = key[i]
}
obj = null;
if (realKeyObj.hasOwnProperty(key[i])) {
obj = storage.getItem(this.name + '.' + key[i] + '.' + realKeyObj[key[i]]);
if (obj) {
obj = JSON.parse(obj)
obj.key = key[i]
}
}
r.push(obj)
}
if (callback) this.lambda(callback).call(this, r)
} else {
var k = this.name + '.' + key
var obj = storage.getItem(k)
if (obj) {
obj = JSON.parse(obj)
obj.key = key
}
realKey = keyCollector(this, key);
if (realKey.length) {
obj = storage.getItem(this.name + '.' + realKey[0]);
if (obj) {
obj = JSON.parse(obj)
obj.key = key
}
}
if (callback) this.lambda(callback).call(this, obj)
}
return this
},

exists: function (key, cb) {
var exists = this.indexer.find(this.name+'.'+key) === false ? false : true ;
var exists = keyCollector(this, key).length ? true : false;
this.lambda(cb).call(this, exists);
return this;
},
// NOTE adapters cannot set this.__results but plugins do
// this probably should be reviewed
all: function (callback) {
var idx = this.indexer.all()
, r = []

var realKey = keyCollector(this)
, r = []
, o
, k
for (var i = 0, l = idx.length; i < l; i++) {
k = idx[i] //v
o = JSON.parse(storage.getItem(k))
o.key = k.replace(this.name + '.', '')
r.push(o)
for (var i = 0, l = realKey.length; i < l; i++) {
o = storage.getItem(this.name + '.' + realKey[i]);
if (o) {
o = JSON.parse(o)
o.key = realKey[i].replace(/\.[^\.]+$/,'');
}
r.push(o);
}

if (callback) this.fn(this.name, callback).call(this, r)
return this
},
Expand All @@ -185,21 +276,22 @@ Lawnchair.adapter('dom', (function() {
removeOne(i);
return this;
}
var key = this.name + '.' +
((keyOrArray.key) ? keyOrArray.key : keyOrArray)
this.indexer.del(key)
storage.removeItem(key)

var realKey = keyCollector(this, keyOrArray.key ? keyOrArray.key : keyOrArray);
if (realKey.length) {
storage.removeItem(this.name + '.' + realKey[0])
}

if (callback) this.lambda(callback).call(this)
return this
},

nuke: function (callback) {
this.all(function(r) {
for (var i = 0, l = r.length; i < l; i++) {
this.remove(r[i]);
}
if (callback) this.lambda(callback).call(this)
})
return this
var realKey = keyCollector(this);
for (var i = 0, l = realKey.length; i < l; i++) {
storage.removeItem(this.name + '.' + realKey[i])
}
if (callback) this.lambda(callback).call(this)
return this
}
}})());