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Diffstat (limited to 'devtools/client/shared/shim/Services.js')
| -rw-r--r-- | devtools/client/shared/shim/Services.js | 620 |
1 files changed, 620 insertions, 0 deletions
diff --git a/devtools/client/shared/shim/Services.js b/devtools/client/shared/shim/Services.js new file mode 100644 index 000000000..97ea51433 --- /dev/null +++ b/devtools/client/shared/shim/Services.js @@ -0,0 +1,620 @@ +/* -*- indent-tabs-mode: nil; js-indent-level: 2 -*- */ +/* vim: set 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"; + +/* globals localStorage, window, document, NodeFilter */ + +// Some constants from nsIPrefBranch.idl. +const PREF_INVALID = 0; +const PREF_STRING = 32; +const PREF_INT = 64; +const PREF_BOOL = 128; +const NS_PREFBRANCH_PREFCHANGE_TOPIC_ID = "nsPref:changed"; + +// We prefix all our local storage items with this. +const PREFIX = "Services.prefs:"; + +/** + * Create a new preference branch. This object conforms largely to + * nsIPrefBranch and nsIPrefService, though it only implements the + * subset needed by devtools. A preference branch can hold child + * preferences while also holding a preference value itself. + * + * @param {PrefBranch} parent the parent branch, or null for the root + * branch. + * @param {String} name the base name of this branch + * @param {String} fullName the fully-qualified name of this branch + */ +function PrefBranch(parent, name, fullName) { + this._parent = parent; + this._name = name; + this._fullName = fullName; + this._observers = {}; + this._children = {}; + + // Properties used when this branch has a value as well. + this._defaultValue = null; + this._hasUserValue = false; + this._userValue = null; + this._type = PREF_INVALID; +} + +PrefBranch.prototype = { + PREF_INVALID: PREF_INVALID, + PREF_STRING: PREF_STRING, + PREF_INT: PREF_INT, + PREF_BOOL: PREF_BOOL, + + /** @see nsIPrefBranch.root. */ + get root() { + return this._fullName; + }, + + /** @see nsIPrefBranch.getPrefType. */ + getPrefType: function (prefName) { + return this._findPref(prefName)._type; + }, + + /** @see nsIPrefBranch.getBoolPref. */ + getBoolPref: function (prefName) { + let thePref = this._findPref(prefName); + if (thePref._type !== PREF_BOOL) { + throw new Error(`${prefName} does not have bool type`); + } + return thePref._get(); + }, + + /** @see nsIPrefBranch.setBoolPref. */ + setBoolPref: function (prefName, value) { + if (typeof value !== "boolean") { + throw new Error("non-bool passed to setBoolPref"); + } + let thePref = this._findOrCreatePref(prefName, value, true, value); + if (thePref._type !== PREF_BOOL) { + throw new Error(`${prefName} does not have bool type`); + } + thePref._set(value); + }, + + /** @see nsIPrefBranch.getCharPref. */ + getCharPref: function (prefName) { + let thePref = this._findPref(prefName); + if (thePref._type !== PREF_STRING) { + throw new Error(`${prefName} does not have string type`); + } + return thePref._get(); + }, + + /** @see nsIPrefBranch.setCharPref. */ + setCharPref: function (prefName, value) { + if (typeof value !== "string") { + throw new Error("non-string passed to setCharPref"); + } + let thePref = this._findOrCreatePref(prefName, value, true, value); + if (thePref._type !== PREF_STRING) { + throw new Error(`${prefName} does not have string type`); + } + thePref._set(value); + }, + + /** @see nsIPrefBranch.getIntPref. */ + getIntPref: function (prefName) { + let thePref = this._findPref(prefName); + if (thePref._type !== PREF_INT) { + throw new Error(`${prefName} does not have int type`); + } + return thePref._get(); + }, + + /** @see nsIPrefBranch.setIntPref. */ + setIntPref: function (prefName, value) { + if (typeof value !== "number") { + throw new Error("non-number passed to setIntPref"); + } + let thePref = this._findOrCreatePref(prefName, value, true, value); + if (thePref._type !== PREF_INT) { + throw new Error(`${prefName} does not have int type`); + } + thePref._set(value); + }, + + /** @see nsIPrefBranch.clearUserPref */ + clearUserPref: function (prefName) { + let thePref = this._findPref(prefName); + thePref._clearUserValue(); + }, + + /** @see nsIPrefBranch.prefHasUserValue */ + prefHasUserValue: function (prefName) { + let thePref = this._findPref(prefName); + return thePref._hasUserValue; + }, + + /** @see nsIPrefBranch.addObserver */ + addObserver: function (domain, observer, holdWeak) { + if (holdWeak) { + throw new Error("shim prefs only supports strong observers"); + } + + if (!(domain in this._observers)) { + this._observers[domain] = []; + } + this._observers[domain].push(observer); + }, + + /** @see nsIPrefBranch.removeObserver */ + removeObserver: function (domain, observer) { + if (!(domain in this._observers)) { + return; + } + let index = this._observers[domain].indexOf(observer); + if (index >= 0) { + this._observers[domain].splice(index, 1); + } + }, + + /** @see nsIPrefService.savePrefFile */ + savePrefFile: function (file) { + if (file) { + throw new Error("shim prefs only supports null file in savePrefFile"); + } + // Nothing to do - this implementation always writes back. + }, + + /** @see nsIPrefService.getBranch */ + getBranch: function (prefRoot) { + if (!prefRoot) { + return this; + } + if (prefRoot.endsWith(".")) { + prefRoot = prefRoot.slice(0, -1); + } + // This is a bit weird since it could erroneously return a pref, + // not a pref branch. + return this._findPref(prefRoot); + }, + + /** + * Return this preference's current value. + * + * @return {Any} The current value of this preference. This may + * return a string, a number, or a boolean depending on the + * preference's type. + */ + _get: function () { + if (this._hasUserValue) { + return this._userValue; + } + return this._defaultValue; + }, + + /** + * Set the preference's value. The new value is assumed to be a + * user value. After setting the value, this function emits a + * change notification. + * + * @param {Any} value the new value + */ + _set: function (value) { + if (!this._hasUserValue || value !== this._userValue) { + this._userValue = value; + this._hasUserValue = true; + this._saveAndNotify(); + } + }, + + /** + * Set the default value for this preference, and emit a + * notification if this results in a visible change. + * + * @param {Any} value the new default value + */ + _setDefault: function (value) { + if (this._defaultValue !== value) { + this._defaultValue = value; + if (!this._hasUserValue) { + this._saveAndNotify(); + } + } + }, + + /** + * If this preference has a user value, clear it. If a change was + * made, emit a change notification. + */ + _clearUserValue: function () { + if (this._hasUserValue) { + this._userValue = null; + this._hasUserValue = false; + this._saveAndNotify(); + } + }, + + /** + * Helper function to write the preference's value to local storage + * and then emit a change notification. + */ + _saveAndNotify: function () { + let store = { + type: this._type, + defaultValue: this._defaultValue, + hasUserValue: this._hasUserValue, + userValue: this._userValue, + }; + + localStorage.setItem(PREFIX + this._fullName, JSON.stringify(store)); + this._parent._notify(this._name); + }, + + /** + * Change this preference's value without writing it back to local + * storage. This is used to handle changes to local storage that + * were made externally. + * + * @param {Number} type one of the PREF_* values + * @param {Any} userValue the user value to use if the pref does not exist + * @param {Any} defaultValue the default value to use if the pref + * does not exist + * @param {Boolean} hasUserValue if a new pref is created, whether + * the default value is also a user value + * @param {Object} store the new value of the preference. It should + * be of the form {type, defaultValue, hasUserValue, userValue}; + * where |type| is one of the PREF_* type constants; |defaultValue| + * and |userValue| are the default and user values, respectively; + * and |hasUserValue| is a boolean indicating whether the user value + * is valid + */ + _storageUpdated: function (type, userValue, hasUserValue, defaultValue) { + this._type = type; + this._defaultValue = defaultValue; + this._hasUserValue = hasUserValue; + this._userValue = userValue; + // There's no need to write this back to local storage, since it + // came from there; and this avoids infinite event loops. + this._parent._notify(this._name); + }, + + /** + * Helper function to find either a Preference or PrefBranch object + * given its name. If the name is not found, throws an exception. + * + * @param {String} prefName the fully-qualified preference name + * @return {Object} Either a Preference or PrefBranch object + */ + _findPref: function (prefName) { + let branchNames = prefName.split("."); + let branch = this; + + for (let branchName of branchNames) { + branch = branch._children[branchName]; + if (!branch) { + throw new Error("could not find pref branch " + prefName); + } + } + + return branch; + }, + + /** + * Helper function to notify any observers when a preference has + * changed. This will also notify the parent branch for further + * reporting. + * + * @param {String} relativeName the name of the updated pref, + * relative to this branch + */ + _notify: function (relativeName) { + for (let domain in this._observers) { + if (relativeName === domain || domain === "" || + (domain.endsWith(".") && relativeName.startsWith(domain))) { + // Allow mutation while walking. + let localList = this._observers[domain].slice(); + for (let observer of localList) { + try { + observer.observe(this, NS_PREFBRANCH_PREFCHANGE_TOPIC_ID, + relativeName); + } catch (e) { + console.error(e); + } + } + } + } + + if (this._parent) { + this._parent._notify(this._name + "." + relativeName); + } + }, + + /** + * Helper function to create a branch given an array of branch names + * representing the path of the new branch. + * + * @param {Array} branchList an array of strings, one per component + * of the branch to be created + * @return {PrefBranch} the new branch + */ + _createBranch: function (branchList) { + let parent = this; + for (let branch of branchList) { + if (!parent._children[branch]) { + let isParentRoot = !parent.parent; + let branchName = (isParentRoot ? "" : parent.root + ".") + branch; + parent._children[branch] = new PrefBranch(parent, branch, branchName); + } + parent = parent._children[branch]; + } + return parent; + }, + + /** + * Create a new preference. The new preference is assumed to be in + * local storage already, and the new value is taken from there. + * + * @param {String} keyName the full-qualified name of the preference. + * This is also the name of the key in local storage. + * @param {Any} userValue the user value to use if the pref does not exist + * @param {Boolean} hasUserValue if a new pref is created, whether + * the default value is also a user value + * @param {Any} defaultValue the default value to use if the pref + * does not exist + * @param {Boolean} init if true, then this call is initialization + * from local storage and should override the default prefs + */ + _findOrCreatePref: function (keyName, userValue, hasUserValue, defaultValue, + init = false) { + let branch = this._createBranch(keyName.split(".")); + + if (hasUserValue && typeof (userValue) !== typeof (defaultValue)) { + throw new Error("inconsistent values when creating " + keyName); + } + + let type; + switch (typeof (defaultValue)) { + case "boolean": + type = PREF_BOOL; + break; + case "number": + type = PREF_INT; + break; + case "string": + type = PREF_STRING; + break; + default: + throw new Error("unhandled argument type: " + typeof (defaultValue)); + } + + if (init || branch._type === PREF_INVALID) { + branch._storageUpdated(type, userValue, hasUserValue, defaultValue); + } else if (branch._type !== type) { + throw new Error("attempt to change type of pref " + keyName); + } + + return branch; + }, + + /** + * Helper function that is called when local storage changes. This + * updates the preferences and notifies pref observers as needed. + * + * @param {StorageEvent} event the event representing the local + * storage change + */ + _onStorageChange: function (event) { + if (event.storageArea !== localStorage) { + return; + } + // Ignore delete events. Not clear what's correct. + if (event.key === null || event.newValue === null) { + return; + } + + let {type, userValue, hasUserValue, defaultValue} = + JSON.parse(event.newValue); + if (event.oldValue === null) { + this._findOrCreatePref(event.key, userValue, hasUserValue, defaultValue); + } else { + let thePref = this._findPref(event.key); + thePref._storageUpdated(type, userValue, hasUserValue, defaultValue); + } + }, + + /** + * Helper function to initialize the root PrefBranch. + */ + _initializeRoot: function () { + if (Services._defaultPrefsEnabled) { + /* eslint-disable no-eval */ + let devtools = require("raw!prefs!devtools/client/preferences/devtools"); + eval(devtools); + let all = require("raw!prefs!modules/libpref/init/all"); + eval(all); + /* eslint-enable no-eval */ + } + + // Read the prefs from local storage and create the local + // representations. + for (let i = 0; i < localStorage.length; ++i) { + let keyName = localStorage.key(i); + if (keyName.startsWith(PREFIX)) { + let {userValue, hasUserValue, defaultValue} = + JSON.parse(localStorage.getItem(keyName)); + this._findOrCreatePref(keyName.slice(PREFIX.length), userValue, + hasUserValue, defaultValue, true); + } + } + + this._onStorageChange = this._onStorageChange.bind(this); + window.addEventListener("storage", this._onStorageChange); + }, +}; + +const Services = { + _prefs: null, + + // For use by tests. If set to false before Services.prefs is used, + // this will disable the reading of the default prefs. + _defaultPrefsEnabled: true, + + /** + * An implementation of nsIPrefService that is based on local + * storage. Only the subset of nsIPrefService that is actually used + * by devtools is implemented here. This is lazily instantiated so + * that the tests have a chance to disable the loading of default + * prefs. + */ + get prefs() { + if (!this._prefs) { + this._prefs = new PrefBranch(null, "", ""); + this._prefs._initializeRoot(); + } + return this._prefs; + }, + + /** + * An implementation of Services.appinfo that holds just the + * properties needed by devtools. + */ + appinfo: { + get OS() { + const os = window.navigator.userAgent; + if (os) { + if (os.includes("Linux")) { + return "Linux"; + } else if (os.includes("Windows")) { + return "WINNT"; + } else if (os.includes("Mac")) { + return "Darwin"; + } + } + return "Unknown"; + }, + + // It's fine for this to be an approximation. + get name() { + return window.navigator.userAgent; + }, + + // It's fine for this to be an approximation. + get version() { + return window.navigator.appVersion; + }, + + // This is only used by telemetry, which is disabled for the + // content case. So, being totally wrong is ok. + get is64Bit() { + return true; + }, + }, + + /** + * A no-op implementation of Services.telemetry. This supports just + * the subset of Services.telemetry that is used by devtools. + */ + telemetry: { + getHistogramById: function (name) { + return { + add: () => {} + }; + }, + + getKeyedHistogramById: function (name) { + return { + add: () => {} + }; + }, + }, + + /** + * An implementation of Services.focus that holds just the + * properties and methods needed by devtools. + * @see nsIFocusManager.idl for details. + */ + focus: { + // These values match nsIFocusManager in order to make testing a + // bit simpler. + MOVEFOCUS_FORWARD: 1, + MOVEFOCUS_BACKWARD: 2, + + get focusedElement() { + if (!document.hasFocus()) { + return null; + } + return document.activeElement; + }, + + moveFocus: function (window, startElement, type, flags) { + if (flags !== 0) { + throw new Error("shim Services.focus.moveFocus only accepts flags===0"); + } + if (type !== Services.focus.MOVEFOCUS_FORWARD + && type !== Services.focus.MOVEFOCUS_BACKWARD) { + throw new Error("shim Services.focus.moveFocus only supports " + + " MOVEFOCUS_FORWARD and MOVEFOCUS_BACKWARD"); + } + + if (!startElement) { + startElement = document.activeElement || document; + } + + let iter = document.createTreeWalker(document, NodeFilter.SHOW_ELEMENT, { + acceptNode: function (node) { + let tabIndex = node.getAttribute("tabindex"); + if (tabIndex === "-1") { + return NodeFilter.FILTER_SKIP; + } + node.focus(); + if (document.activeElement == node) { + return NodeFilter.FILTER_ACCEPT; + } + return NodeFilter.FILTER_SKIP; + } + }); + + iter.currentNode = startElement; + + // Sets the focus via side effect in the filter. + if (type === Services.focus.MOVEFOCUS_FORWARD) { + iter.nextNode(); + } else { + iter.previousNode(); + } + }, + }, + + /** + * An implementation of Services.wm that provides a shim for + * getMostRecentWindow. + */ + wm: { + getMostRecentWindow: function () { + // Having the returned object implement openUILinkIn is + // sufficient for our purposes. + return { + openUILinkIn: function (url) { + window.open(url, "_blank"); + }, + }; + }, + }, +}; + +/** + * Create a new preference. This is used during startup (see + * devtools/client/preferences/devtools.js) to install the + * default preferences. + * + * @param {String} name the name of the preference + * @param {Any} value the default value of the preference + */ +function pref(name, value) { + let thePref = Services.prefs._findOrCreatePref(name, value, true, value); + thePref._setDefault(value); +} + +module.exports = Services; +// This is exported to silence eslint. +exports.pref = pref; |