gecko/dom/datastore/DataStoreCursorImpl.jsm
Jim Blandy 4d6a633bba Bug 914753: Make Emacs file variable header lines correct, or at least consistent. DONTBUILD r=ehsan
The -*- file variable lines -*- establish per-file settings that Emacs will
pick up. This patch makes the following changes to those lines (and touches
nothing else):

 - Never set the buffer's mode.

   Years ago, Emacs did not have a good JavaScript mode, so it made sense
   to use Java or C++ mode in .js files. However, Emacs has had js-mode for
   years now; it's perfectly serviceable, and is available and enabled by
   default in all major Emacs packagings.

   Selecting a mode in the -*- file variable line -*- is almost always the
   wrong thing to do anyway. It overrides Emacs's default choice, which is
   (now) reasonable; and even worse, it overrides settings the user might
   have made in their '.emacs' file for that file extension. It's only
   useful when there's something specific about that particular file that
   makes a particular mode appropriate.

 - Correctly propagate settings that establish the correct indentation
   level for this file: c-basic-offset and js2-basic-offset should be
   js-indent-level. Whatever value they're given should be preserved;
   different parts of our tree use different indentation styles.

 - We don't use tabs in Mozilla JS code. Always set indent-tabs-mode: nil.
   Remove tab-width: settings, at least in files that don't contain tab
   characters.

 - Remove js2-mode settings that belong in the user's .emacs file, like
   js2-skip-preprocessor-directives.
2014-06-24 22:12:07 -07:00

439 lines
13 KiB
JavaScript

/* -*- js-indent-level: 2; indent-tabs-mode: nil -*- */
/* vim: set ft=javascript ts=2 et sw=2 tw=80: */
/* This Source Code Form is subject to the terms of the Mozilla Public
* License, v. 2.0. If a copy of the MPL was not distributed with this
* file, You can obtain one at http://mozilla.org/MPL/2.0/. */
'use strict'
this.EXPORTED_SYMBOLS = ['DataStoreCursor'];
function debug(s) {
//dump('DEBUG DataStoreCursor: ' + s + '\n');
}
const {classes: Cc, interfaces: Ci, utils: Cu, results: Cr} = Components;
const STATE_INIT = 0;
const STATE_REVISION_INIT = 1;
const STATE_REVISION_CHECK = 2;
const STATE_SEND_ALL = 3;
const STATE_REVISION_SEND = 4;
const STATE_DONE = 5;
const REVISION_ADDED = 'added';
const REVISION_UPDATED = 'updated';
const REVISION_REMOVED = 'removed';
const REVISION_VOID = 'void';
const REVISION_SKIP = 'skip'
Cu.import('resource://gre/modules/Services.jsm');
Cu.import('resource://gre/modules/XPCOMUtils.jsm');
/**
* legend:
* - RID = revision ID
* - R = revision object (with the internalRevisionId that is a number)
* - X = current object ID.
* - L = the list of revisions that we have to send
*
* State: init: do you have RID ?
* YES: state->initRevision; loop
* NO: get R; X=0; state->sendAll; send a 'clear'
*
* State: initRevision. Get R from RID. Done?
* YES: state->revisionCheck; loop
* NO: RID = null; state->init; loop
*
* State: revisionCheck: get all the revisions between R and NOW. Done?
* YES and R == NOW: state->done; loop
* YES and R != NOW: Store this revisions in L; state->revisionSend; loop
* NO: R = NOW; X=0; state->sendAll; send a 'clear'
*
* State: sendAll: is R still the last revision?
* YES get the first object with id > X. Done?
* YES: X = object.id; send 'add'
* NO: state->revisionCheck; loop
* NO: R = NOW; X=0; send a 'clear'
*
* State: revisionSend: do you have something from L to send?
* YES and L[0] == 'removed': R=L[0]; send 'remove' with ID
* YES and L[0] == 'added': R=L[0]; get the object; found?
* NO: loop
* YES: send 'add' with ID and object
* YES and L[0] == 'updated': R=L[0]; get the object; found?
* NO: loop
* YES and object.R > R: continue
* YES and object.R <= R: send 'update' with ID and object
* YES L[0] == 'void': R=L[0]; state->init; loop
* NO: state->revisionCheck; loop
*
* State: done: send a 'done' with R
*/
/* Helper functions */
function createDOMError(aWindow, aEvent) {
return new aWindow.DOMError(aEvent.target.error.name);
}
/* DataStoreCursor object */
this.DataStoreCursor = function(aWindow, aDataStore, aRevisionId) {
debug("DataStoreCursor created");
this.init(aWindow, aDataStore, aRevisionId);
}
this.DataStoreCursor.prototype = {
classDescription: 'DataStoreCursor XPCOM Component',
classID: Components.ID('{b6d14349-1eab-46b8-8513-584a7328a26b}'),
contractID: '@mozilla.org/dom/datastore-cursor-impl;1',
QueryInterface: XPCOMUtils.generateQI([Components.interfaces.nsISupports]),
_shuttingdown: false,
_window: null,
_dataStore: null,
_revisionId: null,
_revision: null,
_revisionsList: null,
_objectId: 0,
_state: STATE_INIT,
init: function(aWindow, aDataStore, aRevisionId) {
debug('DataStoreCursor init');
this._window = aWindow;
this._dataStore = aDataStore;
this._revisionId = aRevisionId;
Services.obs.addObserver(this, "inner-window-destroyed", false);
let util = aWindow.QueryInterface(Ci.nsIInterfaceRequestor)
.getInterface(Ci.nsIDOMWindowUtils);
this._innerWindowID = util.currentInnerWindowID;
},
observe: function(aSubject, aTopic, aData) {
let wId = aSubject.QueryInterface(Ci.nsISupportsPRUint64).data;
if (wId == this._innerWindowID) {
Services.obs.removeObserver(this, "inner-window-destroyed");
this._shuttingdown = true;
}
},
// This is the implementation of the state machine.
// Read the comments at the top of this file in order to follow what it does.
stateMachine: function(aStore, aRevisionStore, aResolve, aReject) {
debug('StateMachine: ' + this._state);
// If the window has been destroyed we cannot create the Promise object.
if (this._shuttingdown) {
return;
}
switch (this._state) {
case STATE_INIT:
this.stateMachineInit(aStore, aRevisionStore, aResolve, aReject);
break;
case STATE_REVISION_INIT:
this.stateMachineRevisionInit(aStore, aRevisionStore, aResolve, aReject);
break;
case STATE_REVISION_CHECK:
this.stateMachineRevisionCheck(aStore, aRevisionStore, aResolve, aReject);
break;
case STATE_SEND_ALL:
this.stateMachineSendAll(aStore, aRevisionStore, aResolve, aReject);
break;
case STATE_REVISION_SEND:
this.stateMachineRevisionSend(aStore, aRevisionStore, aResolve, aReject);
break;
case STATE_DONE:
this.stateMachineDone(aStore, aRevisionStore, aResolve, aReject);
break;
}
},
stateMachineInit: function(aStore, aRevisionStore, aResolve, aReject) {
debug('StateMachineInit');
if (this._revisionId) {
this._state = STATE_REVISION_INIT;
this.stateMachine(aStore, aRevisionStore, aResolve, aReject);
return;
}
let self = this;
let request = aRevisionStore.openCursor(null, 'prev');
request.onsuccess = function(aEvent) {
self._revision = aEvent.target.result.value;
self._objectId = 0;
self._state = STATE_SEND_ALL;
aResolve(self.createTask('clear', null, '', null));
}
},
stateMachineRevisionInit: function(aStore, aRevisionStore, aResolve, aReject) {
debug('StateMachineRevisionInit');
let self = this;
let request = this._dataStore._db.getInternalRevisionId(
self._revisionId,
aRevisionStore,
function(aInternalRevisionId) {
// This revision doesn't exist.
if (aInternalRevisionId == undefined) {
self._revisionId = null;
self._objectId = 0;
self._state = STATE_INIT;
self.stateMachine(aStore, aRevisionStore, aResolve, aReject);
return;
}
self._revision = { revisionId: self._revisionId,
internalRevisionId: aInternalRevisionId };
self._state = STATE_REVISION_CHECK;
self.stateMachine(aStore, aRevisionStore, aResolve, aReject);
}
);
},
stateMachineRevisionCheck: function(aStore, aRevisionStore, aResolve, aReject) {
debug('StateMachineRevisionCheck');
let changes = {
addedIds: {},
updatedIds: {},
removedIds: {}
};
let self = this;
let request = aRevisionStore.mozGetAll(
self._window.IDBKeyRange.lowerBound(this._revision.internalRevisionId, true));
request.onsuccess = function(aEvent) {
// Optimize the operations.
for (let i = 0; i < aEvent.target.result.length; ++i) {
let data = aEvent.target.result[i];
switch (data.operation) {
case REVISION_ADDED:
changes.addedIds[data.objectId] = data.internalRevisionId;
break;
case REVISION_UPDATED:
// We don't consider an update if this object has been added
// or if it has been already modified by a previous
// operation.
if (!(data.objectId in changes.addedIds) &&
!(data.objectId in changes.updatedIds)) {
changes.updatedIds[data.objectId] = data.internalRevisionId;
}
break;
case REVISION_REMOVED:
let id = data.objectId;
// If the object has been added in this range of revisions
// we can ignore it and remove it from the list.
if (id in changes.addedIds) {
delete changes.addedIds[id];
} else {
changes.removedIds[id] = data.internalRevisionId;
}
if (id in changes.updatedIds) {
delete changes.updatedIds[id];
}
break;
case REVISION_VOID:
if (i != 0) {
dump('Internal error: Revision "' + REVISION_VOID + '" should not be found!!!\n');
return;
}
self._revisionId = null;
self._objectId = 0;
self._state = STATE_INIT;
self.stateMachine(aStore, aRevisionStore, aResolve, aReject);
return;
}
}
// From changes to a map of internalRevisionId.
let revisions = {};
function addRevisions(obj) {
for (let key in obj) {
revisions[obj[key]] = true;
}
}
addRevisions(changes.addedIds);
addRevisions(changes.updatedIds);
addRevisions(changes.removedIds);
// Create the list of revisions.
let list = [];
for (let i = 0; i < aEvent.target.result.length; ++i) {
let data = aEvent.target.result[i];
// If this revision doesn't contain useful data, we still need to keep
// it in the list because we need to update the internal revision ID.
if (!(data.internalRevisionId in revisions)) {
data.operation = REVISION_SKIP;
}
list.push(data);
}
if (list.length == 0) {
self._state = STATE_DONE;
self.stateMachine(aStore, aRevisionStore, aResolve, aReject);
return;
}
// Some revision has to be sent.
self._revisionsList = list;
self._state = STATE_REVISION_SEND;
self.stateMachine(aStore, aRevisionStore, aResolve, aReject);
};
},
stateMachineSendAll: function(aStore, aRevisionStore, aResolve, aReject) {
debug('StateMachineSendAll');
let self = this;
let request = aRevisionStore.openCursor(null, 'prev');
request.onsuccess = function(aEvent) {
if (self._revision.revisionId != aEvent.target.result.value.revisionId) {
self._revision = aEvent.target.result.value;
self._objectId = 0;
aResolve(self.createTask('clear', null, '', null));
return;
}
let request = aStore.openCursor(self._window.IDBKeyRange.lowerBound(self._objectId, true));
request.onsuccess = function(aEvent) {
let cursor = aEvent.target.result;
if (!cursor) {
self._state = STATE_REVISION_CHECK;
self.stateMachine(aStore, aRevisionStore, aResolve, aReject);
return;
}
self._objectId = cursor.key;
aResolve(self.createTask('add', self._objectId, '', cursor.value));
};
};
},
stateMachineRevisionSend: function(aStore, aRevisionStore, aResolve, aReject) {
debug('StateMachineRevisionSend');
if (!this._revisionsList.length) {
this._state = STATE_REVISION_CHECK;
this.stateMachine(aStore, aRevisionStore, aResolve, aReject);
return;
}
this._revision = this._revisionsList.shift();
switch (this._revision.operation) {
case REVISION_REMOVED:
aResolve(this.createTask('remove', this._revision.objectId, '', null));
break;
case REVISION_ADDED: {
let request = aStore.get(this._revision.objectId);
let self = this;
request.onsuccess = function(aEvent) {
if (aEvent.target.result == undefined) {
self.stateMachine(aStore, aRevisionStore, aResolve, aReject);
return;
}
aResolve(self.createTask('add', self._revision.objectId, '',
aEvent.target.result));
}
break;
}
case REVISION_UPDATED: {
let request = aStore.get(this._revision.objectId);
let self = this;
request.onsuccess = function(aEvent) {
if (aEvent.target.result == undefined) {
self.stateMachine(aStore, aRevisionStore, aResolve, aReject);
return;
}
if (aEvent.target.result.revisionId > self._revision.internalRevisionId) {
self.stateMachine(aStore, aRevisionStore, aResolve, aReject);
return;
}
aResolve(self.createTask('update', self._revision.objectId, '',
aEvent.target.result));
}
break;
}
case REVISION_VOID:
// Internal error!
dump('Internal error: Revision "' + REVISION_VOID + '" should not be found!!!\n');
break;
case REVISION_SKIP:
// This revision contains data that has already been sent by another one.
this.stateMachine(aStore, aRevisionStore, aResolve, aReject);
break;
}
},
stateMachineDone: function(aStore, aRevisionStore, aResolve, aReject) {
this.close();
aResolve(this.createTask('done', null, this._revision.revisionId, null));
},
// public interface
get store() {
return this._dataStore.exposedObject;
},
next: function() {
debug('Next');
// If the window has been destroyed we cannot create the Promise object.
if (this._shuttingdown) {
throw Cr.NS_ERROR_FAILURE;
}
let self = this;
return new this._window.Promise(function(aResolve, aReject) {
self._dataStore._db.cursorTxn(
function(aTxn, aStore, aRevisionStore) {
self.stateMachine(aStore, aRevisionStore, aResolve, aReject);
},
function(aEvent) {
aReject(createDOMError(self._window, aEvent));
}
);
});
},
close: function() {
this._dataStore.syncTerminated(this);
},
createTask: function(aOperation, aId, aRevisionId, aData) {
return Cu.cloneInto({ operation: aOperation, id: aId,
revisionId: aRevisionId, data: aData }, this._window);
}
};