stacktrace-0.3.js

// Domain Public by Eric Wendelin http://eriwen.com/ (2008)
//                  Luke Smith http://lucassmith.name/ (2008)
//                  Loic Dachary <loic@dachary.org> (2008)
//                  Johan Euphrosine <proppy@aminche.com> (2008)
//                  Øyvind Sean Kinsey http://kinsey.no/blog (2010)
//
// Information and discussions
// http://jspoker.pokersource.info/skin/test-printstacktrace.html
// http://eriwen.com/javascript/js-stack-trace/
// http://eriwen.com/javascript/stacktrace-update/
// http://pastie.org/253058
//
// guessFunctionNameFromLines comes from firebug
//
// Software License Agreement (BSD License)
//
// Copyright (c) 2007, Parakey Inc.
// All rights reserved.
//
// Redistribution and use of this software in source and binary forms, with or without modification,
// are permitted provided that the following conditions are met:
//
// * Redistributions of source code must retain the above
//   copyright notice, this list of conditions and the
//   following disclaimer.
//
// * Redistributions in binary form must reproduce the above
//   copyright notice, this list of conditions and the
//   following disclaimer in the documentation and/or other
//   materials provided with the distribution.
//
// * Neither the name of Parakey Inc. nor the names of its
//   contributors may be used to endorse or promote products
//   derived from this software without specific prior
//   written permission of Parakey Inc.
//
// THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS" AND ANY EXPRESS OR
// IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND
// FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR
// CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
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// DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER
// IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT
// OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.

/**
 * Main function giving a function stack trace with a forced or passed in Error 
 *
 * @cfg {Error} e The error to create a stacktrace from (optional)
 * @cfg {Boolean} guess If we should try to resolve the names of anonymous functions
 * @return {Array} of Strings with functions, lines, files, and arguments where possible 
 */
function printStackTrace(options) {
    var ex = (options && options.e) ? options.e : null;
    var guess = options ? !!options.guess : true;
    
    var p = new printStackTrace.implementation();
    var result = p.run(ex);
    return (guess) ? p.guessFunctions(result) : result;
}

printStackTrace.implementation = function() {};

printStackTrace.implementation.prototype = {
    run: function(ex) {
        ex = ex ||
            (function() {
                try {
                    var _err = __undef__ << 1;
                } catch (e) {
                    return e;
                }
            })();
        // Use either the stored mode, or resolve it
        var mode = this._mode || this.mode(ex);
        if (mode === 'other') {
            return this.other(arguments.callee);
        } else {
            return this[mode](ex);
        }
    },
    
    /**
     * @return {String} mode of operation for the environment in question.
     */
    mode: function(e) {
        if (e['arguments']) {
            return (this._mode = 'chrome');
        } else if (window.opera && e.stacktrace) {
            return (this._mode = 'opera10');
        } else if (e.stack) {
            return (this._mode = 'firefox');
        } else if (window.opera && !('stacktrace' in e)) { //Opera 9-
            return (this._mode = 'opera');
        }
        return (this._mode = 'other');
    },

    /**
     * Given a context, function name, and callback function, overwrite it so that it calls
     * printStackTrace() first with a callback and then runs the rest of the body.
     * 
     * @param {Object} context of execution (e.g. window)
     * @param {String} functionName to instrument
     * @param {Function} function to call with a stack trace on invocation
     */
    instrumentFunction: function(context, functionName, callback) {
        context = context || window;
        context['_old' + functionName] = context[functionName];
        context[functionName] = function() { 
            callback.call(this, printStackTrace());
            return context['_old' + functionName].apply(this, arguments);
        };
        context[functionName]._instrumented = true;
    },
    
    /**
     * Given a context and function name of a function that has been
     * instrumented, revert the function to it's original (non-instrumented)
     * state.
     *
     * @param {Object} context of execution (e.g. window)
     * @param {String} functionName to de-instrument
     */
    deinstrumentFunction: function(context, functionName) {
        if (context[functionName].constructor === Function &&
                context[functionName]._instrumented &&
                context['_old' + functionName].constructor === Function) {
            context[functionName] = context['_old' + functionName];
        }
    },
    
    /**
     * Given an Error object, return a formatted Array based on Chrome's stack string.
     * 
     * @param e - Error object to inspect
     * @return Array<String> of function calls, files and line numbers
     */
    chrome: function(e) {
        return e.stack.replace(/^[^\(]+?[\n$]/gm, '').replace(/^\s+at\s+/gm, '').replace(/^Object.<anonymous>\s*\(/gm, '{anonymous}()@').split('\n');
    },

    /**
     * Given an Error object, return a formatted Array based on Firefox's stack string.
     * 
     * @param e - Error object to inspect
     * @return Array<String> of function calls, files and line numbers
     */
    firefox: function(e) {
        return e.stack.replace(/(?:\n@:0)?\s+$/m, '').replace(/^\(/gm, '{anonymous}(').split('\n');
    },

    /**
     * Given an Error object, return a formatted Array based on Opera 10's stacktrace string.
     * 
     * @param e - Error object to inspect
     * @return Array<String> of function calls, files and line numbers
     */
    opera10: function(e) {
        var stack = e.stacktrace;
        var lines = stack.split('\n'), ANON = '{anonymous}',
            lineRE = /.*line (\d+), column (\d+) in ((<anonymous function\:?\s*(\S+))|([^\(]+)\([^\)]*\))(?: in )?(.*)\s*$/i, i, j, len;
        for (i = 2, j = 0, len = lines.length; i < len - 2; i++) {
            if (lineRE.test(lines[i])) {
                var location = RegExp.$6 + ':' + RegExp.$1 + ':' + RegExp.$2;
                var fnName = RegExp.$3;
                fnName = fnName.replace(/<anonymous function\:?\s?(\S+)?>/g, ANON);
                lines[j++] = fnName + '@' + location;
            }
        }
        
        lines.splice(j, lines.length - j);
        return lines;
    },
    
    // Opera 7.x-9.x only!
    opera: function(e) {
        var lines = e.message.split('\n'), ANON = '{anonymous}', 
            lineRE = /Line\s+(\d+).*script\s+(http\S+)(?:.*in\s+function\s+(\S+))?/i, 
            i, j, len;
        
        for (i = 4, j = 0, len = lines.length; i < len; i += 2) {
            //TODO: RegExp.exec() would probably be cleaner here
            if (lineRE.test(lines[i])) {
                lines[j++] = (RegExp.$3 ? RegExp.$3 + '()@' + RegExp.$2 + RegExp.$1 : ANON + '()@' + RegExp.$2 + ':' + RegExp.$1) + ' -- ' + lines[i + 1].replace(/^\s+/, '');
            }
        }
        
        lines.splice(j, lines.length - j);
        return lines;
    },
    
    // Safari, IE, and others
    other: function(curr) {
        var ANON = '{anonymous}', fnRE = /function\s*([\w\-$]+)?\s*\(/i,
            stack = [], j = 0, fn, args;
        
        var maxStackSize = 10;
        while (curr && stack.length < maxStackSize) {
            fn = fnRE.test(curr.toString()) ? RegExp.$1 || ANON : ANON;
            args = Array.prototype.slice.call(curr['arguments']);
            stack[j++] = fn + '(' + this.stringifyArguments(args) + ')';
            curr = curr.caller;
        }
        return stack;
    },
    
    /**
     * Given arguments array as a String, subsituting type names for non-string types.
     *
     * @param {Arguments} object
     * @return {Array} of Strings with stringified arguments
     */
    stringifyArguments: function(args) {
        for (var i = 0; i < args.length; ++i) {
            var arg = args[i];
            if (arg === undefined) {
                args[i] = 'undefined';
            } else if (arg === null) {
                args[i] = 'null';
            } else if (arg.constructor) {
                if (arg.constructor === Array) {
                    if (arg.length < 3) {
                        args[i] = '[' + this.stringifyArguments(arg) + ']';
                    } else {
                        args[i] = '[' + this.stringifyArguments(Array.prototype.slice.call(arg, 0, 1)) + '...' + this.stringifyArguments(Array.prototype.slice.call(arg, -1)) + ']';
                    }
                } else if (arg.constructor === Object) {
                    args[i] = '#object';
                } else if (arg.constructor === Function) {
                    args[i] = '#function';
                } else if (arg.constructor === String) {
                    args[i] = '"' + arg + '"';
                }
            }
        }
        return args.join(',');
    },
    
    sourceCache: {},
    
    /**
     * @return the text from a given URL.
     */
    ajax: function(url) {
        var req = this.createXMLHTTPObject();
        if (!req) {
            return;
        }
        req.open('GET', url, false);
        req.setRequestHeader('User-Agent', 'XMLHTTP/1.0');
        req.send('');
        return req.responseText;
    },
    
    /**
     * Try XHR methods in order and store XHR factory.
     *
     * @return <Function> XHR function or equivalent
     */
    createXMLHTTPObject: function() {
        var xmlhttp, XMLHttpFactories = [
            function() {
                return new XMLHttpRequest();
            }, function() {
                return new ActiveXObject('Msxml2.XMLHTTP');
            }, function() {
                return new ActiveXObject('Msxml3.XMLHTTP');
            }, function() {
                return new ActiveXObject('Microsoft.XMLHTTP');
            }
        ];
        for (var i = 0; i < XMLHttpFactories.length; i++) {
            try {
                xmlhttp = XMLHttpFactories[i]();
                // Use memoization to cache the factory
                this.createXMLHTTPObject = XMLHttpFactories[i];
                return xmlhttp;
            } catch (e) {}
        }
    },

    /**
     * Given a URL, check if it is in the same domain (so we can get the source
     * via Ajax).
     *
     * @param url <String> source url
     * @return False if we need a cross-domain request
     */
    isSameDomain: function(url) {
        return url.indexOf(location.hostname) !== -1;
    },
    
    /**
     * Get source code from given URL if in the same domain.
     *
     * @param url <String> JS source URL
     * @return <String> Source code
     */
    getSource: function(url) {
        if (!(url in this.sourceCache)) {
            this.sourceCache[url] = this.ajax(url).split('\n');
        }
        return this.sourceCache[url];
    },
    
    guessFunctions: function(stack) {
        for (var i = 0; i < stack.length; ++i) {
            var reStack = /\{anonymous\}\(.*\)@(\w+:\/\/([\-\w\.]+)+(:\d+)?[^:]+):(\d+):?(\d+)?/;
            var frame = stack[i], m = reStack.exec(frame);
            if (m) {
                var file = m[1], lineno = m[4]; //m[7] is character position in Chrome
                if (file && this.isSameDomain(file) && lineno) {
                    var functionName = this.guessFunctionName(file, lineno);
                    stack[i] = frame.replace('{anonymous}', functionName);
                }
            }
        }
        return stack;
    },
    
    guessFunctionName: function(url, lineNo) {
        try {
            return this.guessFunctionNameFromLines(lineNo, this.getSource(url));
        } catch (e) {
            return 'getSource failed with url: ' + url + ', exception: ' + e.toString();
        }
    },
    
    guessFunctionNameFromLines: function(lineNo, source) {
        var reFunctionArgNames = /function ([^(]*)\(([^)]*)\)/;
        var reGuessFunction = /['"]?([0-9A-Za-z_]+)['"]?\s*[:=]\s*(function|eval|new Function)/;
        // Walk backwards from the first line in the function until we find the line which
        // matches the pattern above, which is the function definition
        var line = "", maxLines = 10;
        for (var i = 0; i < maxLines; ++i) {
            line = source[lineNo - i] + line;
            if (line !== undefined) {
                var m = reGuessFunction.exec(line);
                if (m && m[1]) {
                    return m[1];
                } else {
                    m = reFunctionArgNames.exec(line);
                    if (m && m[1]) {
                        return m[1];
                    }
                }
            }
        }
        return '(?)';
    }
};