michael@0: # This Source Code Form is subject to the terms of the Mozilla Public
michael@0: # License, v. 2.0. If a copy of the MPL was not distributed with this
michael@0: # file, You can obtain one at http://mozilla.org/MPL/2.0/.
michael@0: 
michael@0: import os, sys
michael@0: import base64
michael@0: import simplejson as json
michael@0: 
michael@0: def create_jid():
michael@0:     """Return 'jid1-XYZ', where 'XYZ' is a randomly-generated string. (in the
michael@0:     previous jid0- series, the string securely identified a specific public
michael@0:     key). To get a suitable add-on ID, append '@jetpack' to this string.
michael@0:     """
michael@0:     # per https://developer.mozilla.org/en/Install_Manifests#id all XPI id
michael@0:     # values must either be in the form of a 128-bit GUID (crazy braces
michael@0:     # and all) or in the form of an email address (crazy @ and all).
michael@0:     # Firefox will refuse to install an add-on with an id that doesn't
michael@0:     # match one of these forms. The actual regexp is at:
michael@0:     # http://mxr.mozilla.org/mozilla-central/source/toolkit/mozapps/extensions/internal/XPIProvider.jsm#130
michael@0:     # So the JID needs an @-suffix, and the only legal punctuation is
michael@0:     # "-._". So we start with a base64 encoding, and replace the
michael@0:     # punctuation (+/) with letters (AB), losing a few bits of integrity.
michael@0: 
michael@0:     # even better: windows has a maximum path length limitation of 256
michael@0:     # characters:
michael@0:     #  http://msdn.microsoft.com/en-us/library/aa365247%28VS.85%29.aspx
michael@0:     # (unless all paths are prefixed with "\\?\", I kid you not). The
michael@0:     # typical install will put add-on code in a directory like:
michael@0:     # C:\Documents and Settings\<username>\Application Data\Mozilla\Firefox\Profiles\232353483.default\extensions\$JID\...
michael@0:     # (which is 108 chars long without the $JID).
michael@0:     # Then the unpacked XPI contains packaged resources like:
michael@0:     #  resources/$JID-api-utils-lib/main.js   (35 chars plus the $JID)
michael@0:     #
michael@0:     # We create a random 80 bit string, base64 encode that (with
michael@0:     # AB instead of +/ to be path-safe), then bundle it into
michael@0:     # "jid1-XYZ@jetpack". This gives us 27 characters. The resulting
michael@0:     # main.js will have a path length of 211 characters, leaving us 45
michael@0:     # characters of margin.
michael@0:     #
michael@0:     # 80 bits is enough to generate one billion JIDs and still maintain lower
michael@0:     # than a one-in-a-million chance of accidental collision. (1e9 JIDs is 30
michael@0:     # bits, square for the "birthday-paradox" to get 60 bits, add 20 bits for
michael@0:     # the one-in-a-million margin to get 80 bits)
michael@0: 
michael@0:     # if length were no issue, we'd prefer to use this:
michael@0:     h = os.urandom(80/8)
michael@0:     s = base64.b64encode(h, "AB").strip("=")
michael@0:     jid = "jid1-" + s
michael@0:     return jid
michael@0: 
michael@0: def preflight_config(target_cfg, filename, stderr=sys.stderr):
michael@0:     modified = False
michael@0:     config = json.load(open(filename, 'r'))
michael@0: 
michael@0:     if "id" not in config:
michael@0:         print >>stderr, ("No 'id' in package.json: creating a new ID for you.")
michael@0:         jid = create_jid()
michael@0:         config["id"] = jid
michael@0:         modified = True
michael@0: 
michael@0:     if modified:
michael@0:         i = 0
michael@0:         backup = filename + ".backup"
michael@0:         while os.path.exists(backup):
michael@0:             if i > 1000:
michael@0:                 raise ValueError("I'm having problems finding a good name"
michael@0:                                  " for the backup file. Please move %s out"
michael@0:                                  " of the way and try again."
michael@0:                                  % (filename + ".backup"))
michael@0:             backup = filename + ".backup-%d" % i
michael@0:             i += 1
michael@0:         os.rename(filename, backup)
michael@0:         new_json = json.dumps(config, indent=4)
michael@0:         open(filename, 'w').write(new_json+"\n")
michael@0:         return False, True
michael@0: 
michael@0:     return True, False