From 6738cf228beb241b17a2ac4a0a49227a7114a799 Mon Sep 17 00:00:00 2001
From: Thomas Leonard <talex5@gmail.com>
Date: Sun, 25 Jan 2009 14:07:49 +0000
Subject: [PATCH] New --add-digest option allows adding additional manifest
 digests

These are added to the <manifest-digest> element, which is created if
necessary. This allows a smooth upgrade to newer digest algorithms
without breaking old clients.
---
 0publish     |  4 +++
 digest.py    | 79 ++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
 validator.py |  1 +
 3 files changed, 84 insertions(+)
 create mode 100644 digest.py

diff --git a/0publish b/0publish
index 8d35b0e..dc142ca 100755
--- a/0publish
+++ b/0publish
@@ -15,6 +15,7 @@ parser.add_option("--archive-url", help="add archive at this URL", action='store
 parser.add_option("--archive-file", help="local copy of archive-url", action='store', metavar='FILE')
 parser.add_option("--archive-extract", help="subdirectory of archive to extract", action='store', metavar='DIR')
 parser.add_option("-c", "--create", help="create file if nonexistant", action='store_true')
+parser.add_option("-d", "--add-digest", help="add extra digests", action='store', metavar='ALG')
 parser.add_option("-e", "--edit", help="edit with $EDITOR", action='store_true')
 parser.add_option("-g", "--gpgsign", help="add a GPG signature block", action='store_true')
 parser.add_option("-k", "--key", help="key to use for signing")
@@ -150,6 +151,9 @@ try:
 	if options.local:
 		import merge
 		data = merge.merge(data, options.local)
+	if options.add_digest:
+		import digest
+		data = digest.add_digests(data, alg = options.add_digest)
 	if options.edit:
 		data = edit.edit(data)
 
diff --git a/digest.py b/digest.py
new file mode 100644
index 0000000..d2777ec
--- /dev/null
+++ b/digest.py
@@ -0,0 +1,79 @@
+from xml.dom import minidom
+from zeroinstall.injector import namespaces
+from zeroinstall.zerostore import manifest, Stores, NotStored
+import xmltools
+from logging import info
+
+stores = Stores()
+
+def digests(impl):
+	yield impl.getAttribute('id').split('=', 1)
+	for x in xmltools.children(impl, 'manifest-digest'):
+		for name, value in x.attributes.itemsNS():
+			if name[0] is None:
+				yield name[1], value
+
+def get_version(impl):
+	while impl:
+		v = impl.getAttribute('version')
+		if v: return v
+		impl = impl.parentNode
+
+def add_digest(impl, alg_name):
+	alg = manifest.get_algorithm(alg_name)
+	
+	# Scan through the existing digests
+	# - If we've already got the one we need, return
+	# - Otherwise, find a cached implementation we can use
+	existing_path = None
+	for a, value in digests(impl):
+		digest = '%s=%s' % (a, value)
+		if a == alg_name:
+			return False			# Already signed with this algorithm
+		if not existing_path:
+			try:
+				existing_path = stores.lookup(digest)
+				if existing_path:
+					existing_digest = digest
+			except NotStored:
+				pass		# OK
+
+	if existing_path is None:
+		print "No implementations of %s cached; can't calculate new digest" % get_version(impl)
+		return False
+
+	info("Verifying %s", existing_path)
+	manifest.verify(existing_path, existing_digest)
+
+	print "Adding new digest to version %s" % get_version(impl)
+
+	new_digest = alg.new_digest()
+	for line in alg.generate_manifest(existing_path):
+		new_digest.update(line + '\n')
+
+	for md in xmltools.children(impl, 'manifest-digest'):
+		break
+	else:
+		md = xmltools.create_element(impl, 'manifest-digest')
+	md.setAttribute(alg_name, new_digest.hexdigest())
+
+	return True
+
+def add_digests(data, alg = None):
+	doc = minidom.parseString(data)
+
+	if alg is None:
+		alg = 'sha1new'
+	
+	changed = False
+	for impl in doc.documentElement.getElementsByTagNameNS(namespaces.XMLNS_IFACE, 'implementation'):
+		if impl.getAttribute('id') in "./":
+			continue		# Local implementation
+
+		if add_digest(impl, alg):
+			changed = True
+
+	if changed:
+		return doc.toxml()
+	else:
+		return data
diff --git a/validator.py b/validator.py
index 5df10b9..217ffdd 100644
--- a/validator.py
+++ b/validator.py
@@ -22,6 +22,7 @@ known_elements = {
 	'group' : group_impl_attribs,
 	'implementation' : ['id'] + group_impl_attribs,
 	'package-implementation' : ['package', 'main'],
+	'manifest-digest' : ['sha1new', 'sha256'],
 
 	'archive' : ['href', 'size', 'extract', 'type', 'start-offset'],
 	'recipe' : [],
-- 
2.11.4.GIT