gecko-dev/browser/devtools/shared/Console.jsm
2012-05-21 12:12:37 +01:00

366 lines
10 KiB
JavaScript

/* 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)
*/
const EXPORTED_SYMBOLS = [ "console" ];
Components.utils.import("resource://gre/modules/XPCOMUtils.jsm");
/**
* 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 left 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. The only customization
* allowed currently is 'truncate' which can take the value "start" to
* truncate strings from the start as opposed to the end.
* @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 {
return aStr.substring(0, aMaxLen - 1) + "_";
}
}
if (aStr.length < aMinLen) {
return Array(aMinLen - aStr.length + 1).join(" ") + aStr;
}
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.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
* @return {string}
* A single line representation of aThing, which will generally be at
* most 80 chars long
*/
function stringify(aThing) {
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 + fmt(json, 50, 0);
}
if (typeof aThing == "function") {
return fmt(aThing.toString().replace(/\s+/g, " "), 80, 0);
}
let str = aThing.toString().replace(/\n/g, "|");
return fmt(str, 80, 0);
}
/**
* 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 == "Error") {
reply += " " + aThing.message + "\n";
reply += logProperty("stack", aThing.stack);
}
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]);
}, this);
}
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;
}
/**
* Parse a stack trace, returning an array of stack frame objects, where
* each has file/line/call 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({
file: posn.split(":")[0],
line: posn.split(":")[1],
call: line.substring(0, at)
});
}, this);
return trace;
}
/**
* parseStack() takes output from an exception from which it creates the an
* array of stack frame objects, this has the same output but using data from
* Components.stack
*
* @param {string} aFrame
* The stack frame from which to begin the walk
* @return {object[]}
* Array of { file: "...", line: NNN, call: "..." } objects
*/
function getStack(aFrame) {
if (!aFrame) {
aFrame = Components.stack.caller;
}
let trace = [];
while (aFrame) {
trace.push({
file: aFrame.filename,
line: aFrame.lineNumber,
call: aFrame.name
});
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.file, 20, 20, { truncate: "start" }) + " " +
fmt(frame.line, 5, 5) + " " +
fmt(frame.call, 75, 75) + "\n";
});
return reply;
}
/**
* 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() {
let args = Array.prototype.slice.call(arguments, 0);
let data = args.map(function(arg) {
return stringify(arg);
});
dump(aLevel + ": " + data.join(", ") + "\n");
};
}
/**
* 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() {
dump(aLevel + "\n");
let args = Array.prototype.slice.call(arguments, 0);
args.forEach(function(arg) {
dump(log(arg));
});
};
}
/**
* This creates a console object that somewhat replicates Firebug's console
* object. It currently writes to dump(), but should write to the web
* console's chrome error section (when it has one)
*/
const console = {
debug: createMultiLineDumper("debug"),
log: createDumper("log"),
info: createDumper("info"),
warn: createDumper("warn"),
error: createMultiLineDumper("error"),
trace: function Console_trace() {
let trace = getStack(Components.stack.caller);
dump(formatTrace(trace) + "\n");
},
clear: function Console_clear() {},
dir: createMultiLineDumper("dir"),
dirxml: createMultiLineDumper("dirxml"),
group: createDumper("group"),
groupEnd: createDumper("groupEnd")
};