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