Console.jsm
/* 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";
/**
* Define a 'console' API to roughly match the implementation provided by
* Firebug.
* This module helps cases where code is shared between the web and Firefox.
* See also Browser.jsm for an implementation of other web constants to help
* sharing code between the web and firefox;
*
* The API is only be a rough approximation for 3 reasons:
* - The Firebug console API is implemented in many places with differences in
* the implementations, so there isn't a single reference to adhere to
* - The Firebug console is a rich display compared with dump(), so there will
* be many things that we can't replicate
* - The primary use of this API is debugging and error logging so the perfect
* implementation isn't always required (or even well defined)
*/
this.EXPORTED_SYMBOLS = [ "console", "ConsoleAPI" ];
const {classes: Cc, interfaces: Ci, utils: Cu} = Components;
Cu.import("resource://gre/modules/XPCOMUtils.jsm");
XPCOMUtils.defineLazyModuleGetter(this, "Services",
"resource://gre/modules/Services.jsm");
let gTimerRegistry = new Map();
/**
* String utility to ensure that strings are a specified length. Strings
* that are too long are truncated to the max length and the last char is
* set to "_". Strings that are too short are padded with spaces.
*
* @param {string} aStr
* The string to format to the correct length
* @param {number} aMaxLen
* The maximum allowed length of the returned string
* @param {number} aMinLen (optional)
* The minimum allowed length of the returned string. If undefined,
* then aMaxLen will be used
* @param {object} aOptions (optional)
* An object allowing format customization. Allowed customizations:
* 'truncate' - can take the value "start" to truncate strings from
* the start as opposed to the end or "center" to truncate
* strings in the center.
* 'align' - takes an alignment when padding is needed for MinLen,
* either "start" or "end". Defaults to "start".
* @return {string}
* The original string formatted to fit the specified lengths
*/
function fmt(aStr, aMaxLen, aMinLen, aOptions) {
if (aMinLen == null) {
aMinLen = aMaxLen;
}
if (aStr == null) {
aStr = "";
}
if (aStr.length > aMaxLen) {
if (aOptions && aOptions.truncate == "start") {
return "_" + aStr.substring(aStr.length - aMaxLen + 1);
}
else if (aOptions && aOptions.truncate == "center") {
let start = aStr.substring(0, (aMaxLen / 2));
let end = aStr.substring((aStr.length - (aMaxLen / 2)) + 1);
return start + "_" + end;
}
else {
return aStr.substring(0, aMaxLen - 1) + "_";
}
}
if (aStr.length < aMinLen) {
let padding = Array(aMinLen - aStr.length + 1).join(" ");
aStr = (aOptions.align === "end") ? padding + aStr : aStr + padding;
}
return aStr;
}
/**
* Utility to extract the constructor name of an object.
* Object.toString gives: "[object ?????]"; we want the "?????".
*
* @param {object} aObj
* The object from which to extract the constructor name
* @return {string}
* The constructor name
*/
function getCtorName(aObj) {
if (aObj === null) {
return "null";
}
if (aObj === undefined) {
return "undefined";
}
if (aObj.constructor && aObj.constructor.name) {
return aObj.constructor.name;
}
// If that fails, use Objects toString which sometimes gives something
// better than 'Object', and at least defaults to Object if nothing better
return Object.prototype.toString.call(aObj).slice(8, -1);
}
/**
* A single line stringification of an object designed for use by humans
*
* @param {any} aThing
* The object to be stringified
* @param {boolean} aAllowNewLines
* @return {string}
* A single line representation of aThing, which will generally be at
* most 80 chars long
*/
function stringify(aThing, aAllowNewLines) {
if (aThing === undefined) {
return "undefined";
}
if (aThing === null) {
return "null";
}
if (typeof aThing == "object") {
let type = getCtorName(aThing);
if (aThing instanceof Components.interfaces.nsIDOMNode && aThing.tagName) {
return debugElement(aThing);
}
type = (type == "Object" ? "" : type + " ");
let json;
try {
json = JSON.stringify(aThing);
}
catch (ex) {
// Can't use a real ellipsis here, because cmd.exe isn't unicode-enabled
json = "{" + Object.keys(aThing).join(":..,") + ":.., " + "}";
}
return type + json;
}
if (typeof aThing == "function") {
return aThing.toString().replace(/\s+/g, " ");
}
let str = aThing.toString();
if (!aAllowNewLines) {
str = str.replace(/\n/g, "|");
}
return str;
}
/**
* Create a simple debug representation of a given element.
*
* @param {nsIDOMElement} aElement
* The element to debug
* @return {string}
* A simple single line representation of aElement
*/
function debugElement(aElement) {
return "<" + aElement.tagName +
(aElement.id ? "#" + aElement.id : "") +
(aElement.className ?
"." + aElement.className.split(" ").join(" .") :
"") +
">";
}
/**
* A multi line stringification of an object, designed for use by humans
*
* @param {any} aThing
* The object to be stringified
* @return {string}
* A multi line representation of aThing
*/
function log(aThing) {
if (aThing === null) {
return "null\n";
}
if (aThing === undefined) {
return "undefined\n";
}
if (typeof aThing == "object") {
let reply = "";
let type = getCtorName(aThing);
if (type == "Map") {
reply += "Map\n";
for (let [key, value] of aThing) {
reply += logProperty(key, value);
}
}
else if (type == "Set") {
let i = 0;
reply += "Set\n";
for (let value of aThing) {
reply += logProperty('' + i, value);
i++;
}
}
else if (type.match("Error$") ||
(typeof aThing.name == "string" &&
aThing.name.match("NS_ERROR_"))) {
reply += " Message: " + aThing + "\n";
if (aThing.stack) {
reply += " Stack:\n";
var frame = aThing.stack;
while (frame) {
reply += " " + frame + "\n";
frame = frame.caller;
}
}
}
else if (aThing instanceof Components.interfaces.nsIDOMNode && aThing.tagName) {
reply += " " + debugElement(aThing) + "\n";
}
else {
let keys = Object.getOwnPropertyNames(aThing);
if (keys.length > 0) {
reply += type + "\n";
keys.forEach(function(aProp) {
reply += logProperty(aProp, aThing[aProp]);
});
}
else {
reply += type + "\n";
let root = aThing;
let logged = [];
while (root != null) {
let properties = Object.keys(root);
properties.sort();
properties.forEach(function(property) {
if (!(property in logged)) {
logged[property] = property;
reply += logProperty(property, aThing[property]);
}
});
root = Object.getPrototypeOf(root);
if (root != null) {
reply += ' - prototype ' + getCtorName(root) + '\n';
}
}
}
}
return reply;
}
return " " + aThing.toString() + "\n";
}
/**
* Helper for log() which converts a property/value pair into an output
* string
*
* @param {string} aProp
* The name of the property to include in the output string
* @param {object} aValue
* Value assigned to aProp to be converted to a single line string
* @return {string}
* Multi line output string describing the property/value pair
*/
function logProperty(aProp, aValue) {
let reply = "";
if (aProp == "stack" && typeof value == "string") {
let trace = parseStack(aValue);
reply += formatTrace(trace);
}
else {
reply += " - " + aProp + " = " + stringify(aValue) + "\n";
}
return reply;
}
const LOG_LEVELS = {
"all": Number.MIN_VALUE,
"debug": 2,
"log": 3,
"info": 3,
"trace": 3,
"timeEnd": 3,
"time": 3,
"group": 3,
"groupEnd": 3,
"dir": 3,
"dirxml": 3,
"warn": 4,
"error": 5,
"off": Number.MAX_VALUE,
};
/**
* Helper to tell if a console message of `aLevel` type
* should be logged in stdout and sent to consoles given
* the current maximum log level being defined in `console.maxLogLevel`
*
* @param {string} aLevel
* Console message log level
* @param {string} aMaxLevel {string}
* String identifier (See LOG_LEVELS for possible
* values) that allows to filter which messages
* are logged based on their log level
* @return {boolean}
* Should this message be logged or not?
*/
function shouldLog(aLevel, aMaxLevel) {
return LOG_LEVELS[aMaxLevel] <= LOG_LEVELS[aLevel];
}
/**
* Parse a stack trace, returning an array of stack frame objects, where
* each has filename/lineNumber/functionName members
*
* @param {string} aStack
* The serialized stack trace
* @return {object[]}
* Array of { file: "...", line: NNN, call: "..." } objects
*/
function parseStack(aStack) {
let trace = [];
aStack.split("\n").forEach(function(line) {
if (!line) {
return;
}
let at = line.lastIndexOf("@");
let posn = line.substring(at + 1);
trace.push({
filename: posn.split(":")[0],
lineNumber: posn.split(":")[1],
functionName: line.substring(0, at)
});
});
return trace;
}
/**
* Format a frame coming from Components.stack such that it can be used by the
* Browser Console, via console-api-log-event notifications.
*
* @param {object} aFrame
* The stack frame from which to begin the walk.
* @param {number=0} aMaxDepth
* Maximum stack trace depth. Default is 0 - no depth limit.
* @return {object[]}
* An array of {filename, lineNumber, functionName, language} objects.
* These objects follow the same format as other console-api-log-event
* messages.
*/
function getStack(aFrame, aMaxDepth = 0) {
if (!aFrame) {
aFrame = Components.stack.caller;
}
let trace = [];
while (aFrame) {
trace.push({
filename: aFrame.filename,
lineNumber: aFrame.lineNumber,
functionName: aFrame.name,
language: aFrame.language,
});
if (aMaxDepth == trace.length) {
break;
}
aFrame = aFrame.caller;
}
return trace;
}
/**
* Take the output from parseStack() and convert it to nice readable
* output
*
* @param {object[]} aTrace
* Array of trace objects as created by parseStack()
* @return {string} Multi line report of the stack trace
*/
function formatTrace(aTrace) {
let reply = "";
aTrace.forEach(function(frame) {
reply += fmt(frame.filename, 20, 20, { truncate: "start" }) + " " +
fmt(frame.lineNumber, 5, 5) + " " +
fmt(frame.functionName, 75, 0, { truncate: "center" }) + "\n";
});
return reply;
}
/**
* Create a new timer by recording the current time under the specified name.
*
* @param {string} aName
* The name of the timer.
* @param {number} [aTimestamp=Date.now()]
* Optional timestamp that tells when the timer was originally started.
* @return {object}
* The name property holds the timer name and the started property
* holds the time the timer was started. In case of error, it returns
* an object with the single property "error" that contains the key
* for retrieving the localized error message.
*/
function startTimer(aName, aTimestamp) {
let key = aName.toString();
if (!gTimerRegistry.has(key)) {
gTimerRegistry.set(key, aTimestamp || Date.now());
}
return { name: aName, started: gTimerRegistry.get(key) };
}
/**
* Stop the timer with the specified name and retrieve the elapsed time.
*
* @param {string} aName
* The name of the timer.
* @param {number} [aTimestamp=Date.now()]
* Optional timestamp that tells when the timer was originally stopped.
* @return {object}
* The name property holds the timer name and the duration property
* holds the number of milliseconds since the timer was started.
*/
function stopTimer(aName, aTimestamp) {
let key = aName.toString();
let duration = (aTimestamp || Date.now()) - gTimerRegistry.get(key);
gTimerRegistry.delete(key);
return { name: aName, duration: duration };
}
/**
* Dump a new message header to stdout by taking care of adding an eventual
* prefix
*
* @param {object} aConsole
* ConsoleAPI instance
* @param {string} aLevel
* The string identifier for the message log level
* @param {string} aMessage
* The string message to print to stdout
*/
function dumpMessage(aConsole, aLevel, aMessage) {
aConsole.dump(
"console." + aLevel + ": " +
aConsole.prefix +
aMessage + "\n"
);
}
/**
* Create a function which will output a concise level of output when used
* as a logging function
*
* @param {string} aLevel
* A prefix to all output generated from this function detailing the
* level at which output occurred
* @return {function}
* A logging function
* @see createMultiLineDumper()
*/
function createDumper(aLevel) {
return function() {
if (!shouldLog(aLevel, this.maxLogLevel)) {
return;
}
let args = Array.prototype.slice.call(arguments, 0);
let frame = getStack(Components.stack.caller, 1)[0];
sendConsoleAPIMessage(this, aLevel, frame, args);
let data = args.map(function(arg) {
return stringify(arg, true);
});
dumpMessage(this, aLevel, data.join(" "));
};
}
/**
* Create a function which will output more detailed level of output when
* used as a logging function
*
* @param {string} aLevel
* A prefix to all output generated from this function detailing the
* level at which output occurred
* @return {function}
* A logging function
* @see createDumper()
*/
function createMultiLineDumper(aLevel) {
return function() {
if (!shouldLog(aLevel, this.maxLogLevel)) {
return;
}
dumpMessage(this, aLevel, "");
let args = Array.prototype.slice.call(arguments, 0);
let frame = getStack(Components.stack.caller, 1)[0];
sendConsoleAPIMessage(this, aLevel, frame, args);
args.forEach(function(arg) {
this.dump(log(arg));
}, this);
};
}
/**
* Send a Console API message. This function will send a console-api-log-event
* notification through the nsIObserverService.
*
* @param {object} aConsole
* The instance of ConsoleAPI performing the logging.
* @param {string} aLevel
* Message severity level. This is usually the name of the console method
* that was called.
* @param {object} aFrame
* The youngest stack frame coming from Components.stack, as formatted by
* getStack().
* @param {array} aArgs
* The arguments given to the console method.
* @param {object} aOptions
* Object properties depend on the console method that was invoked:
* - timer: for time() and timeEnd(). Holds the timer information.
* - groupName: for group(), groupCollapsed() and groupEnd().
* - stacktrace: for trace(). Holds the array of stack frames as given by
* getStack().
*/
function sendConsoleAPIMessage(aConsole, aLevel, aFrame, aArgs, aOptions = {})
{
let consoleEvent = {
ID: "jsm",
innerID: aConsole.innerID || aFrame.filename,
level: aLevel,
filename: aFrame.filename,
lineNumber: aFrame.lineNumber,
functionName: aFrame.functionName,
timeStamp: Date.now(),
arguments: aArgs,
};
consoleEvent.wrappedJSObject = consoleEvent;
switch (aLevel) {
case "trace":
consoleEvent.stacktrace = aOptions.stacktrace;
break;
case "time":
case "timeEnd":
consoleEvent.timer = aOptions.timer;
break;
case "group":
case "groupCollapsed":
case "groupEnd":
try {
consoleEvent.groupName = Array.prototype.join.call(aArgs, " ");
}
catch (ex) {
Cu.reportError(ex);
Cu.reportError(ex.stack);
return;
}
break;
}
Services.obs.notifyObservers(consoleEvent, "console-api-log-event", null);
let ConsoleAPIStorage = Cc["@mozilla.org/consoleAPI-storage;1"]
.getService(Ci.nsIConsoleAPIStorage);
ConsoleAPIStorage.recordEvent("jsm", consoleEvent);
}
/**
* This creates a console object that somewhat replicates Firebug's console
* object
*
* @param {object} aConsoleOptions
* Optional dictionary with a set of runtime console options:
* - prefix {string} : An optional prefix string to be printed before
* the actual logged message
* - maxLogLevel {string} : String identifier (See LOG_LEVELS for
* possible values) that allows to filter which
* messages are logged based on their log level.
* If falsy value, all messages will be logged.
* If wrong value that doesn't match any key of
* LOG_LEVELS, no message will be logged
* - dump {function} : An optional function to intercept all strings
* written to stdout
* - innerID {string}: An ID representing the source of the message.
* Normally the inner ID of a DOM window.
* @return {object}
* A console API instance object
*/
function ConsoleAPI(aConsoleOptions = {}) {
// Normalize console options to set default values
// in order to avoid runtime checks on each console method call.
this.dump = aConsoleOptions.dump || dump;
this.prefix = aConsoleOptions.prefix || "";
this.maxLogLevel = aConsoleOptions.maxLogLevel || "all";
this.innerID = aConsoleOptions.innerID || null;
// Bind all the functions to this object.
for (let prop in this) {
if (typeof(this[prop]) === "function") {
this[prop] = this[prop].bind(this);
}
}
}
ConsoleAPI.prototype = {
debug: createMultiLineDumper("debug"),
log: createDumper("log"),
info: createDumper("info"),
warn: createDumper("warn"),
error: createMultiLineDumper("error"),
exception: createMultiLineDumper("error"),
trace: function Console_trace() {
if (!shouldLog("trace", this.maxLogLevel)) {
return;
}
let args = Array.prototype.slice.call(arguments, 0);
let trace = getStack(Components.stack.caller);
sendConsoleAPIMessage(this, "trace", trace[0], args,
{ stacktrace: trace });
dumpMessage(this, "trace", "\n" + formatTrace(trace));
},
clear: function Console_clear() {},
dir: createMultiLineDumper("dir"),
dirxml: createMultiLineDumper("dirxml"),
group: createDumper("group"),
groupEnd: createDumper("groupEnd"),
time: function Console_time() {
if (!shouldLog("time", this.maxLogLevel)) {
return;
}
let args = Array.prototype.slice.call(arguments, 0);
let frame = getStack(Components.stack.caller, 1)[0];
let timer = startTimer(args[0]);
sendConsoleAPIMessage(this, "time", frame, args, { timer: timer });
dumpMessage(this, "time",
"'" + timer.name + "' @ " + (new Date()));
},
timeEnd: function Console_timeEnd() {
if (!shouldLog("timeEnd", this.maxLogLevel)) {
return;
}
let args = Array.prototype.slice.call(arguments, 0);
let frame = getStack(Components.stack.caller, 1)[0];
let timer = stopTimer(args[0]);
sendConsoleAPIMessage(this, "timeEnd", frame, args, { timer: timer });
dumpMessage(this, "timeEnd",
"'" + timer.name + "' " + timer.duration + "ms");
},
};
this.console = new ConsoleAPI();
this.ConsoleAPI = ConsoleAPI;
