1.1 --- /dev/null Thu Jan 01 00:00:00 1970 +0000
1.2 +++ b/dom/datastore/DataStoreCursorImpl.jsm Wed Dec 31 06:09:35 2014 +0100
1.3 @@ -0,0 +1,409 @@
1.4 +/* -*- Mode: js2; js2-basic-offset: 2; indent-tabs-mode: nil; -*- */
1.5 +/* vim: set ft=javascript ts=2 et sw=2 tw=80: */
1.6 +/* This Source Code Form is subject to the terms of the Mozilla Public
1.7 + * License, v. 2.0. If a copy of the MPL was not distributed with this
1.8 + * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
1.9 +
1.10 +'use strict'
1.11 +
1.12 +this.EXPORTED_SYMBOLS = ['DataStoreCursor'];
1.13 +
1.14 +function debug(s) {
1.15 + //dump('DEBUG DataStoreCursor: ' + s + '\n');
1.16 +}
1.17 +
1.18 +const {classes: Cc, interfaces: Ci, utils: Cu, results: Cr} = Components;
1.19 +
1.20 +const STATE_INIT = 0;
1.21 +const STATE_REVISION_INIT = 1;
1.22 +const STATE_REVISION_CHECK = 2;
1.23 +const STATE_SEND_ALL = 3;
1.24 +const STATE_REVISION_SEND = 4;
1.25 +const STATE_DONE = 5;
1.26 +
1.27 +const REVISION_ADDED = 'added';
1.28 +const REVISION_UPDATED = 'updated';
1.29 +const REVISION_REMOVED = 'removed';
1.30 +const REVISION_VOID = 'void';
1.31 +const REVISION_SKIP = 'skip'
1.32 +
1.33 +Cu.import('resource://gre/modules/XPCOMUtils.jsm');
1.34 +
1.35 +/**
1.36 + * legend:
1.37 + * - RID = revision ID
1.38 + * - R = revision object (with the internalRevisionId that is a number)
1.39 + * - X = current object ID.
1.40 + * - L = the list of revisions that we have to send
1.41 + *
1.42 + * State: init: do you have RID ?
1.43 + * YES: state->initRevision; loop
1.44 + * NO: get R; X=0; state->sendAll; send a 'clear'
1.45 + *
1.46 + * State: initRevision. Get R from RID. Done?
1.47 + * YES: state->revisionCheck; loop
1.48 + * NO: RID = null; state->init; loop
1.49 + *
1.50 + * State: revisionCheck: get all the revisions between R and NOW. Done?
1.51 + * YES and R == NOW: state->done; loop
1.52 + * YES and R != NOW: Store this revisions in L; state->revisionSend; loop
1.53 + * NO: R = NOW; X=0; state->sendAll; send a 'clear'
1.54 + *
1.55 + * State: sendAll: is R still the last revision?
1.56 + * YES get the first object with id > X. Done?
1.57 + * YES: X = object.id; send 'add'
1.58 + * NO: state->revisionCheck; loop
1.59 + * NO: R = NOW; X=0; send a 'clear'
1.60 + *
1.61 + * State: revisionSend: do you have something from L to send?
1.62 + * YES and L[0] == 'removed': R=L[0]; send 'remove' with ID
1.63 + * YES and L[0] == 'added': R=L[0]; get the object; found?
1.64 + * NO: loop
1.65 + * YES: send 'add' with ID and object
1.66 + * YES and L[0] == 'updated': R=L[0]; get the object; found?
1.67 + * NO: loop
1.68 + * YES and object.R > R: continue
1.69 + * YES and object.R <= R: send 'update' with ID and object
1.70 + * YES L[0] == 'void': R=L[0]; state->init; loop
1.71 + * NO: state->revisionCheck; loop
1.72 + *
1.73 + * State: done: send a 'done' with R
1.74 + */
1.75 +
1.76 +/* Helper functions */
1.77 +function createDOMError(aWindow, aEvent) {
1.78 + return new aWindow.DOMError(aEvent.target.error.name);
1.79 +}
1.80 +
1.81 +/* DataStoreCursor object */
1.82 +this.DataStoreCursor = function(aWindow, aDataStore, aRevisionId) {
1.83 + debug("DataStoreCursor created");
1.84 + this.init(aWindow, aDataStore, aRevisionId);
1.85 +}
1.86 +
1.87 +this.DataStoreCursor.prototype = {
1.88 + classDescription: 'DataStoreCursor XPCOM Component',
1.89 + classID: Components.ID('{b6d14349-1eab-46b8-8513-584a7328a26b}'),
1.90 + contractID: '@mozilla.org/dom/datastore-cursor-impl;1',
1.91 + QueryInterface: XPCOMUtils.generateQI([Components.interfaces.nsISupports]),
1.92 +
1.93 + _window: null,
1.94 + _dataStore: null,
1.95 + _revisionId: null,
1.96 + _revision: null,
1.97 + _revisionsList: null,
1.98 + _objectId: 0,
1.99 +
1.100 + _state: STATE_INIT,
1.101 +
1.102 + init: function(aWindow, aDataStore, aRevisionId) {
1.103 + debug('DataStoreCursor init');
1.104 +
1.105 + this._window = aWindow;
1.106 + this._dataStore = aDataStore;
1.107 + this._revisionId = aRevisionId;
1.108 + },
1.109 +
1.110 + // This is the implementation of the state machine.
1.111 + // Read the comments at the top of this file in order to follow what it does.
1.112 + stateMachine: function(aStore, aRevisionStore, aResolve, aReject) {
1.113 + debug('StateMachine: ' + this._state);
1.114 +
1.115 + switch (this._state) {
1.116 + case STATE_INIT:
1.117 + this.stateMachineInit(aStore, aRevisionStore, aResolve, aReject);
1.118 + break;
1.119 +
1.120 + case STATE_REVISION_INIT:
1.121 + this.stateMachineRevisionInit(aStore, aRevisionStore, aResolve, aReject);
1.122 + break;
1.123 +
1.124 + case STATE_REVISION_CHECK:
1.125 + this.stateMachineRevisionCheck(aStore, aRevisionStore, aResolve, aReject);
1.126 + break;
1.127 +
1.128 + case STATE_SEND_ALL:
1.129 + this.stateMachineSendAll(aStore, aRevisionStore, aResolve, aReject);
1.130 + break;
1.131 +
1.132 + case STATE_REVISION_SEND:
1.133 + this.stateMachineRevisionSend(aStore, aRevisionStore, aResolve, aReject);
1.134 + break;
1.135 +
1.136 + case STATE_DONE:
1.137 + this.stateMachineDone(aStore, aRevisionStore, aResolve, aReject);
1.138 + break;
1.139 + }
1.140 + },
1.141 +
1.142 + stateMachineInit: function(aStore, aRevisionStore, aResolve, aReject) {
1.143 + debug('StateMachineInit');
1.144 +
1.145 + if (this._revisionId) {
1.146 + this._state = STATE_REVISION_INIT;
1.147 + this.stateMachine(aStore, aRevisionStore, aResolve, aReject);
1.148 + return;
1.149 + }
1.150 +
1.151 + let self = this;
1.152 + let request = aRevisionStore.openCursor(null, 'prev');
1.153 + request.onsuccess = function(aEvent) {
1.154 + self._revision = aEvent.target.result.value;
1.155 + self._objectId = 0;
1.156 + self._state = STATE_SEND_ALL;
1.157 + aResolve(Cu.cloneInto({ operation: 'clear' }, self._window));
1.158 + }
1.159 + },
1.160 +
1.161 + stateMachineRevisionInit: function(aStore, aRevisionStore, aResolve, aReject) {
1.162 + debug('StateMachineRevisionInit');
1.163 +
1.164 + let self = this;
1.165 + let request = this._dataStore._db.getInternalRevisionId(
1.166 + self._revisionId,
1.167 + aRevisionStore,
1.168 + function(aInternalRevisionId) {
1.169 + // This revision doesn't exist.
1.170 + if (aInternalRevisionId == undefined) {
1.171 + self._revisionId = null;
1.172 + self._objectId = 0;
1.173 + self._state = STATE_INIT;
1.174 + self.stateMachine(aStore, aRevisionStore, aResolve, aReject);
1.175 + return;
1.176 + }
1.177 +
1.178 + self._revision = { revisionId: self._revisionId,
1.179 + internalRevisionId: aInternalRevisionId };
1.180 + self._state = STATE_REVISION_CHECK;
1.181 + self.stateMachine(aStore, aRevisionStore, aResolve, aReject);
1.182 + }
1.183 + );
1.184 + },
1.185 +
1.186 + stateMachineRevisionCheck: function(aStore, aRevisionStore, aResolve, aReject) {
1.187 + debug('StateMachineRevisionCheck');
1.188 +
1.189 + let changes = {
1.190 + addedIds: {},
1.191 + updatedIds: {},
1.192 + removedIds: {}
1.193 + };
1.194 +
1.195 + let self = this;
1.196 + let request = aRevisionStore.mozGetAll(
1.197 + self._window.IDBKeyRange.lowerBound(this._revision.internalRevisionId, true));
1.198 + request.onsuccess = function(aEvent) {
1.199 +
1.200 + // Optimize the operations.
1.201 + for (let i = 0; i < aEvent.target.result.length; ++i) {
1.202 + let data = aEvent.target.result[i];
1.203 +
1.204 + switch (data.operation) {
1.205 + case REVISION_ADDED:
1.206 + changes.addedIds[data.objectId] = data.internalRevisionId;
1.207 + break;
1.208 +
1.209 + case REVISION_UPDATED:
1.210 + // We don't consider an update if this object has been added
1.211 + // or if it has been already modified by a previous
1.212 + // operation.
1.213 + if (!(data.objectId in changes.addedIds) &&
1.214 + !(data.objectId in changes.updatedIds)) {
1.215 + changes.updatedIds[data.objectId] = data.internalRevisionId;
1.216 + }
1.217 + break;
1.218 +
1.219 + case REVISION_REMOVED:
1.220 + let id = data.objectId;
1.221 +
1.222 + // If the object has been added in this range of revisions
1.223 + // we can ignore it and remove it from the list.
1.224 + if (id in changes.addedIds) {
1.225 + delete changes.addedIds[id];
1.226 + } else {
1.227 + changes.removedIds[id] = data.internalRevisionId;
1.228 + }
1.229 +
1.230 + if (id in changes.updatedIds) {
1.231 + delete changes.updatedIds[id];
1.232 + }
1.233 + break;
1.234 +
1.235 + case REVISION_VOID:
1.236 + if (i != 0) {
1.237 + dump('Internal error: Revision "' + REVISION_VOID + '" should not be found!!!\n');
1.238 + return;
1.239 + }
1.240 +
1.241 + self._revisionId = null;
1.242 + self._objectId = 0;
1.243 + self._state = STATE_INIT;
1.244 + self.stateMachine(aStore, aRevisionStore, aResolve, aReject);
1.245 + return;
1.246 + }
1.247 + }
1.248 +
1.249 + // From changes to a map of internalRevisionId.
1.250 + let revisions = {};
1.251 + function addRevisions(obj) {
1.252 + for (let key in obj) {
1.253 + revisions[obj[key]] = true;
1.254 + }
1.255 + }
1.256 +
1.257 + addRevisions(changes.addedIds);
1.258 + addRevisions(changes.updatedIds);
1.259 + addRevisions(changes.removedIds);
1.260 +
1.261 + // Create the list of revisions.
1.262 + let list = [];
1.263 + for (let i = 0; i < aEvent.target.result.length; ++i) {
1.264 + let data = aEvent.target.result[i];
1.265 +
1.266 + // If this revision doesn't contain useful data, we still need to keep
1.267 + // it in the list because we need to update the internal revision ID.
1.268 + if (!(data.internalRevisionId in revisions)) {
1.269 + data.operation = REVISION_SKIP;
1.270 + }
1.271 +
1.272 + list.push(data);
1.273 + }
1.274 +
1.275 + if (list.length == 0) {
1.276 + self._state = STATE_DONE;
1.277 + self.stateMachine(aStore, aRevisionStore, aResolve, aReject);
1.278 + return;
1.279 + }
1.280 +
1.281 + // Some revision has to be sent.
1.282 + self._revisionsList = list;
1.283 + self._state = STATE_REVISION_SEND;
1.284 + self.stateMachine(aStore, aRevisionStore, aResolve, aReject);
1.285 + };
1.286 + },
1.287 +
1.288 + stateMachineSendAll: function(aStore, aRevisionStore, aResolve, aReject) {
1.289 + debug('StateMachineSendAll');
1.290 +
1.291 + let self = this;
1.292 + let request = aRevisionStore.openCursor(null, 'prev');
1.293 + request.onsuccess = function(aEvent) {
1.294 + if (self._revision.revisionId != aEvent.target.result.value.revisionId) {
1.295 + self._revision = aEvent.target.result.value;
1.296 + self._objectId = 0;
1.297 + aResolve(Cu.cloneInto({ operation: 'clear' }, self._window));
1.298 + return;
1.299 + }
1.300 +
1.301 + let request = aStore.openCursor(self._window.IDBKeyRange.lowerBound(self._objectId, true));
1.302 + request.onsuccess = function(aEvent) {
1.303 + let cursor = aEvent.target.result;
1.304 + if (!cursor) {
1.305 + self._state = STATE_REVISION_CHECK;
1.306 + self.stateMachine(aStore, aRevisionStore, aResolve, aReject);
1.307 + return;
1.308 + }
1.309 +
1.310 + self._objectId = cursor.key;
1.311 + aResolve(Cu.cloneInto({ operation: 'add', id: self._objectId,
1.312 + data: cursor.value }, self._window));
1.313 + };
1.314 + };
1.315 + },
1.316 +
1.317 + stateMachineRevisionSend: function(aStore, aRevisionStore, aResolve, aReject) {
1.318 + debug('StateMachineRevisionSend');
1.319 +
1.320 + if (!this._revisionsList.length) {
1.321 + this._state = STATE_REVISION_CHECK;
1.322 + this.stateMachine(aStore, aRevisionStore, aResolve, aReject);
1.323 + return;
1.324 + }
1.325 +
1.326 + this._revision = this._revisionsList.shift();
1.327 +
1.328 + switch (this._revision.operation) {
1.329 + case REVISION_REMOVED:
1.330 + aResolve(Cu.cloneInto({ operation: 'remove', id: this._revision.objectId },
1.331 + this._window));
1.332 + break;
1.333 +
1.334 + case REVISION_ADDED: {
1.335 + let request = aStore.get(this._revision.objectId);
1.336 + let self = this;
1.337 + request.onsuccess = function(aEvent) {
1.338 + if (aEvent.target.result == undefined) {
1.339 + self.stateMachine(aStore, aRevisionStore, aResolve, aReject);
1.340 + return;
1.341 + }
1.342 +
1.343 + aResolve(Cu.cloneInto({ operation: 'add', id: self._revision.objectId,
1.344 + data: aEvent.target.result }, self._window));
1.345 + }
1.346 + break;
1.347 + }
1.348 +
1.349 + case REVISION_UPDATED: {
1.350 + let request = aStore.get(this._revision.objectId);
1.351 + let self = this;
1.352 + request.onsuccess = function(aEvent) {
1.353 + if (aEvent.target.result == undefined) {
1.354 + self.stateMachine(aStore, aRevisionStore, aResolve, aReject);
1.355 + return;
1.356 + }
1.357 +
1.358 + if (aEvent.target.result.revisionId > self._revision.internalRevisionId) {
1.359 + self.stateMachine(aStore, aRevisionStore, aResolve, aReject);
1.360 + return;
1.361 + }
1.362 +
1.363 + aResolve(Cu.cloneInto({ operation: 'update', id: self._revision.objectId,
1.364 + data: aEvent.target.result }, self._window));
1.365 + }
1.366 + break;
1.367 + }
1.368 +
1.369 + case REVISION_VOID:
1.370 + // Internal error!
1.371 + dump('Internal error: Revision "' + REVISION_VOID + '" should not be found!!!\n');
1.372 + break;
1.373 +
1.374 + case REVISION_SKIP:
1.375 + // This revision contains data that has already been sent by another one.
1.376 + this.stateMachine(aStore, aRevisionStore, aResolve, aReject);
1.377 + break;
1.378 + }
1.379 + },
1.380 +
1.381 + stateMachineDone: function(aStore, aRevisionStore, aResolve, aReject) {
1.382 + this.close();
1.383 + aResolve(Cu.cloneInto({ revisionId: this._revision.revisionId,
1.384 + operation: 'done' }, this._window));
1.385 + },
1.386 +
1.387 + // public interface
1.388 +
1.389 + get store() {
1.390 + return this._dataStore.exposedObject;
1.391 + },
1.392 +
1.393 + next: function() {
1.394 + debug('Next');
1.395 +
1.396 + let self = this;
1.397 + return new this._window.Promise(function(aResolve, aReject) {
1.398 + self._dataStore._db.cursorTxn(
1.399 + function(aTxn, aStore, aRevisionStore) {
1.400 + self.stateMachine(aStore, aRevisionStore, aResolve, aReject);
1.401 + },
1.402 + function(aEvent) {
1.403 + aReject(createDOMError(self._window, aEvent));
1.404 + }
1.405 + );
1.406 + });
1.407 + },
1.408 +
1.409 + close: function() {
1.410 + this._dataStore.syncTerminated(this);
1.411 + }
1.412 +};
