Metacat

#!/usr/bin/env python

#

# Merge multiple JavaScript source code files into one.

#

# Usage:

# This script requires source files to have dependencies specified in them.

#

# Dependencies are specified with a comment of the form:

#

#     // @requires <file path>

#

#  e.g.

#

#    // @requires Geo/DataSource.js

#

#  or (ideally) within a class comment definition

#

#     /**

#      * @class

#      *

#      * @requires OpenLayers/Layer.js

#      */

#

# This script should be executed like so:

#

#     mergejs.py <output.js> <directory> [...]

#

# e.g.

#

#     mergejs.py openlayers.js Geo/ CrossBrowser/

#

#  This example will cause the script to walk the `Geo` and

#  `CrossBrowser` directories--and subdirectories thereof--and import

#  all `*.js` files encountered. The dependency declarations will be extracted

#  and then the source code from imported files will be output to 

#  a file named `openlayers.js` in an order which fulfils the dependencies

#  specified.

#

#

# Note: This is a very rough initial version of this code.

#

# -- Copyright 2005-2006 MetaCarta, Inc. / OpenLayers project --

#

# TODO: Allow files to be excluded. e.g. `Crossbrowser/DebugMode.js`?

# TODO: Report error when dependency can not be found rather than KeyError.

import re

import os

import sys

SUFFIX_JAVASCRIPT = ".js"

RE_REQUIRE = "@requires (.*)\n" # TODO: Ensure in comment?

class SourceFile:

    """

    Represents a Javascript source code file.

    """

    def __init__(self, filepath, source):

        """

        """

        self.filepath = filepath

        self.source = source

        self.requiredBy = []

    def _getRequirements(self):

        """

        Extracts the dependencies specified in the source code and returns

        a list of them.

        """

        # TODO: Cache?

        return re.findall(RE_REQUIRE, self.source)

    requires = property(fget=_getRequirements, doc="")

def usage(filename):

    """

    Displays a usage message.

    """

    print "%s [-c <config file>] <output.js> <directory> [...]" % filename

class Config:

    """

    Represents a parsed configuration file.

    A configuration file should be of the following form:

        [first]

        3rd/prototype.js

        core/application.js

        core/params.js

        [last]

        core/api.js

        [exclude]

        3rd/logger.js

    All headings are required.

    The files listed in the `first` section will be forced to load

    *before* all other files (in the order listed). The files in `last`

    section will be forced to load *after* all the other files (in the

    order listed).

    The files list in the `exclude` section will not be imported.

    """

    def __init__(self, filename):

        """

        Parses the content of the named file and stores the values.

        """

        lines = [line[:-1] # Assumes end-of-line character is present

                 for line in open(filename)

                 if line != "\n"] # Skip blank lines

        self.forceFirst = \

                    lines[lines.index("[first]") + 1:lines.index("[last]")]

        self.forceLast = \

                      lines[lines.index("[last]") + 1:lines.index("[exclude]")]

        self.exclude =  lines[lines.index("[exclude]") + 1:]

if __name__ == "__main__":

    import getopt

    options, args = getopt.getopt(sys.argv[1:], "-c:")

    try:

        outputFilename = args[0]

    except IndexError:

        usage(sys.argv[0])

        raise SystemExit

    else:

        sourceDirectory = args[1]

        if not sourceDirectory:

            usage(sys.argv[0])

            raise SystemExit

    cfg = None

    if options and options[0][0] == "-c":

        filename = options[0][1]

        print "Parsing configuration file: %s" % filename

        cfg = Config(filename)

    allFiles = []

    ## Find all the Javascript source files

    for root, dirs, files in os.walk(sourceDirectory):

	for filename in files:

	    if filename.endswith(SUFFIX_JAVASCRIPT) and not filename.startswith("."):

		filepath = os.path.join(root, filename)[len(sourceDirectory)+1:]

		if (not cfg) or (filepath not in cfg.exclude):

		    allFiles.append(filepath)

    ## Header inserted at the start of each file in the output

    HEADER = "/* " + "=" * 70 + "\n"\

             "    %s\n" +\

             "   " + "=" * 70 + " */\n\n"

    files = {}

    order = [] # List of filepaths to output, in a dependency satisfying order 

    ## Import file source code

    ## TODO: Do import when we walk the directories above?

    for filepath in allFiles:

        print "Importing: %s" % filepath

	fullpath = os.path.join(sourceDirectory, filepath)

        content = open(fullpath, "U").read() # TODO: Ensure end of line @ EOF?

        files[filepath] = SourceFile(filepath, content) # TODO: Chop path?

    ## Resolve the dependencies

    print "\nResolving dependencies...\n"

    from toposort import toposort

    nodes = []

    routes = []

    for filepath, info in files.items():

        nodes.append(filepath)

        for neededFilePath in info.requires:

            routes.append((neededFilePath, filepath))

    for dependencyLevel in toposort(nodes, routes):

        for filepath in dependencyLevel:

            order.append(filepath)

    ## Move forced first and last files to the required position

    if cfg:

        print "Re-ordering files...\n"

        order = cfg.forceFirst + \

                    [item

                     for item in order

                     if ((item not in cfg.forceFirst) and

                         (item not in cfg.forceLast))] + \

                cfg.forceLast

    ## Double check all dependencies have been met

    for fp in order:

        if max([order.index(rfp) for rfp in files[fp].requires] +

               [order.index(fp)]) != order.index(fp):

            print "Inconsistent!"

            raise SystemExit

    ## Output the files in the determined order

    result = []

    for fp in order:

        f = files[fp]

        print "Exporting: ", f.filepath

        result.append(HEADER % f.filepath)

        source = f.source

        result.append(source)

        if not source.endswith("\n"):

            result.append("\n")

    print "\nTotal files merged: %d " % len(allFiles)

    print "\nGenerating: %s" % (outputFilename)

    open(outputFilename, "w").write("".join(result))