blamejs.js

/**
 * BlameJS is a JavaScript parser for inflating a data object from the
 * output of a git blame -p (for porcelain) operation
 * 
 * For more information on the structure of the porcelain format, see
 * http://www.kernel.org/pub/software/scm/git/docs/git-blame.html
 * 
 * @author Matt Pardee
 * @license GPLv3 <http://www.gnu.org/licenses/gpl.txt>
 */

define(function(require, exports, module) {

module.exports = (function() {
    
    function BlameJS() {
        this.commit_data = {};
        this.line_data   = {};

        this.settingCommitData = false;
        this.currentCommitHash = "";
        this.currentLineNumber = 1;
    }

    BlameJS.prototype = {
        getCommitData : function() {
            return this.commit_data;
        },

        getLineData : function() {
            return this.line_data;
        },

        /**
         * The entry point for parsing the output from git blame -p
         * 
         * @param {string} blame The output as a string
         */
        parseBlame : function(blame) {
    
            // Split up the original document into an array of lines
            this.lines = blame.split('\n');
            if (!this.lines.length)
                return false;
    
            // Go through each line
            for (var i = 0; i < this.lines.length; i++) {
    
                // If we detect a tab character we know it's a line of code
                // So we can reset stateful variables
                if (this.lines[i][0] == "\t") {
                    // The first tab is an addition made by git, so get rid of it
                    this.line_data[this.currentLineNumber].code = this.lines[i].substr(1);
                    this.settingCommitData = false;
                    this.currentCommitHash = "";
                }
    
                else {
                    var arrLine = this.lines[i].split(" ");
    
                    // If we are in the process of collecting data about a commit summary
                    if (this.settingCommitData)
                        this.parseCommitLine(arrLine);
    
                    else {
                        // 40 == the length of an Sha1
                        // This is really only an added check, we should be guaranteed
                        // that an Sha1 is expected here
                        if (arrLine[0].length == 40) {
                            this.currentCommitHash = arrLine[0];
                            this.currentLineNumber = arrLine[2];
    
                            // Setup the new line_data hash
                            this.line_data[arrLine[2]] = {
                                  code : ''
                                , hash : this.currentCommitHash
                                , originalLine : arrLine[1]
                                , finalLine    : arrLine[2]
                                , numLines     : arrLine[3] || -1
                            };
    
                            // Since the commit data (author, committer, summary, etc) only
                            // appear once in a porcelain output for every commit, we set
                            // it up once here and then expect that the next 8-11 lines of
                            // the file are dedicated to that data
                            if (!this.commit_data[arrLine[0]]) {
                                this.settingCommitData = true;
                                this.commit_data[arrLine[0]] = {
                                      author        : ''
                                    , authorMail    : ''
                                    , authorTime    : ''
                                    , authorTz      : ''
                                    , committer     : ''
                                    , committerMail : ''
                                    , committerTime : ''
                                    , committerTz   : ''
                                    , summary       : ''
                                    , previousHash  : ''
                                    , filename      : ''
                                };
                            }
                        }
                    }
                }
            }

            return true;
        },
    
        /**
         * Parses and sets data from a line following a commit header
         * 
         * @param {array} lineArr The current line split by a space
         */
        parseCommitLine : function(lineArr) {
            switch(lineArr[0]) {
                case "author":
                    this.commit_data[this.currentCommitHash].author = lineArr.slice(1).join(" ");
                    break;
    
                case "author-mail":
                    this.commit_data[this.currentCommitHash].authorMail = lineArr[1];
                    break;
    
                case "author-time":
                    this.commit_data[this.currentCommitHash].authorTime = lineArr[1];
                    break;
    
                case "author-tz":
                    this.commit_data[this.currentCommitHash].authorTz = lineArr[1];
                    break;
    
                case "committer":
                    this.commit_data[this.currentCommitHash].committer = lineArr.slice(1).join(" ");
                    break;
    
                case "committer-mail":
                    this.commit_data[this.currentCommitHash].committerMail = lineArr[1];
                    break;
    
                case "committer-time":
                    this.commit_data[this.currentCommitHash].committerTime = lineArr[1];
                    break;
    
                case "committer-tz":
                    this.commit_data[this.currentCommitHash].committerTz = lineArr[1];
                    break;
    
                case "summary":
                    this.commit_data[this.currentCommitHash].summary = lineArr.slice(1).join(" ");
                    break;
    
                case "filename":
                    this.commit_data[this.currentCommitHash].filename = lineArr[1];
                    break;
    
                case "previous":
                    this.commit_data[this.currentCommitHash].previous = lineArr.slice(1).join(" ");
                    break;
    
                default:
                    break;
            }
        }
    };

    return BlameJS;
})();

});