diff --git a/tools/releasetools/edify_generator.py b/tools/releasetools/edify_generator.py
new file mode 100644
index 0000000..e7a15cd
--- /dev/null
+++ b/tools/releasetools/edify_generator.py
@@ -0,0 +1,226 @@
+# Copyright (C) 2009 The Android Open Source Project
+#
+# Licensed under the Apache License, Version 2.0 (the "License");
+# you may not use this file except in compliance with the License.
+# You may obtain a copy of the License at
+#
+#      http://www.apache.org/licenses/LICENSE-2.0
+#
+# Unless required by applicable law or agreed to in writing, software
+# distributed under the License is distributed on an "AS IS" BASIS,
+# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+# See the License for the specific language governing permissions and
+# limitations under the License.
+
+import os
+import re
+
+import common
+
+class EdifyGenerator(object):
+  """Class to generate scripts in the 'edify' recovery script language
+  used from donut onwards."""
+
+  def __init__(self, version):
+    self.script = []
+    self.mounts = set()
+    self.version = version
+
+  def MakeTemporary(self):
+    """Make a temporary script object whose commands can latter be
+    appended to the parent script with AppendScript().  Used when the
+    caller wants to generate script commands out-of-order."""
+    x = EdifyGenerator(self.version)
+    x.mounts = self.mounts
+    return x
+
+  @staticmethod
+  def _WordWrap(cmd, linelen=80):
+    """'cmd' should be a function call with null characters after each
+    parameter (eg, "somefun(foo,\0bar,\0baz)").  This function wraps cmd
+    to a given line length, replacing nulls with spaces and/or newlines
+    to format it nicely."""
+    indent = cmd.index("(")+1
+    out = []
+    first = True
+    x = re.compile("^(.{,%d})\0" % (linelen-indent,))
+    while True:
+      if not first:
+        out.append(" " * indent)
+      first = False
+      m = x.search(cmd)
+      if not m:
+        parts = cmd.split("\0", 1)
+        out.append(parts[0]+"\n")
+        if len(parts) == 1:
+          break
+        else:
+          cmd = parts[1]
+          continue
+      out.append(m.group(1)+"\n")
+      cmd = cmd[m.end():]
+
+    return "".join(out).replace("\0", " ").rstrip("\n")
+
+  def AppendScript(self, other):
+    """Append the contents of another script (which should be created
+    with temporary=True) to this one."""
+    self.script.extend(other.script)
+
+  def AssertSomeFingerprint(self, *fp):
+    """Assert that the current system build fingerprint is one of *fp."""
+    if not fp:
+      raise ValueError("must specify some fingerprints")
+    cmd = ('assert(' +
+           ' ||\0'.join([('file_getprop("/system/build.prop", '
+                         '"ro.build.fingerprint") == "%s"')
+                        % i for i in fp]) +
+           ');')
+    self.script.append(self._WordWrap(cmd))
+
+  def AssertOlderBuild(self, timestamp):
+    """Assert that the build on the device is older (or the same as)
+    the given timestamp."""
+    self.script.append(('assert(!less_than_int(%s, '
+                        'getprop("ro.build.date.utc")));') % (timestamp,))
+
+  def AssertDevice(self, device):
+    """Assert that the device identifier is the given string."""
+    cmd = ('assert(getprop("ro.product.device") == "%s" ||\0'
+           'getprop("ro.build.product") == "%s");' % (device, device))
+    self.script.append(self._WordWrap(cmd))
+
+  def AssertSomeBootloader(self, *bootloaders):
+    """Asert that the bootloader version is one of *bootloaders."""
+    cmd = ("assert(" +
+           " ||\0".join(['getprop("ro.bootloader") == "%s"' % (b,)
+                         for b in bootloaders]) +
+           ");")
+    self.script.append(self._WordWrap(cmd))
+
+  def ShowProgress(self, frac, dur):
+    """Update the progress bar, advancing it over 'frac' over the next
+    'dur' seconds."""
+    self.script.append("show_progress(%f, %d);" % (frac, int(dur)))
+
+  def PatchCheck(self, filename, *sha1):
+    """Check that the given file (or MTD reference) has one of the
+    given *sha1 hashes."""
+    self.script.append('assert(apply_patch_check("%s"' % (filename,) +
+                       "".join([', "%s"' % (i,) for i in sha1]) +
+                       '));')
+
+  def CacheFreeSpaceCheck(self, amount):
+    """Check that there's at least 'amount' space that can be made
+    available on /cache."""
+    self.script.append("assert(apply_patch_space(%d));" % (amount,))
+
+  def Mount(self, kind, what, path):
+    """Mount the given 'what' at the given path.  'what' should be a
+    partition name if kind is "MTD", or a block device if kind is
+    "vfat".  No other values of 'kind' are supported."""
+    self.script.append('mount("%s", "%s", "%s");' % (kind, what, path))
+    self.mounts.add(path)
+
+  def UnpackPackageDir(self, src, dst):
+    """Unpack a given directory from the OTA package into the given
+    destination directory."""
+    self.script.append('package_extract_dir("%s", "%s");' % (src, dst))
+
+  def Comment(self, comment):
+    """Write a comment into the update script."""
+    self.script.append("")
+    for i in comment.split("\n"):
+      self.script.append("# " + i)
+    self.script.append("")
+
+  def Print(self, message):
+    """Log a message to the screen (if the logs are visible)."""
+    self.script.append('ui_print("%s");' % (message,))
+
+  def FormatPartition(self, partition):
+    """Format the given MTD partition."""
+    self.script.append('format("MTD", "%s");' % (partition,))
+
+  def DeleteFiles(self, file_list):
+    """Delete all files in file_list."""
+    if not file_list: return
+    cmd = "delete(" + ",\0".join(['"%s"' % (i,) for i in file_list]) + ");"
+    self.script.append(self._WordWrap(cmd))
+
+  def ApplyPatch(self, srcfile, tgtfile, tgtsize, tgtsha1, *patchpairs):
+    """Apply binary patches (in *patchpairs) to the given srcfile to
+    produce tgtfile (which may be "-" to indicate overwriting the
+    source file."""
+    if len(patchpairs) % 2 != 0 or len(patchpairs) == 0:
+      raise ValueError("bad patches given to ApplyPatch")
+    cmd = ['apply_patch("%s",\0"%s",\0%s,\0%d'
+           % (srcfile, tgtfile, tgtsha1, tgtsize)]
+    for i in range(0, len(patchpairs), 2):
+      cmd.append(',\0"%s:%s"' % patchpairs[i:i+2])
+    cmd.append(');')
+    cmd = "".join(cmd)
+    self.script.append(self._WordWrap(cmd))
+
+  def WriteFirmwareImage(self, kind, fn):
+    """Arrange to update the given firmware image (kind must be
+    "hboot" or "radio") when recovery finishes."""
+    if self.version == 1:
+      self.script.append(
+          ('assert(package_extract_file("%(fn)s", "/tmp/%(kind)s.img"),\n'
+           '       write_firmware_image("/tmp/%(kind)s.img", "%(kind)s"));')
+          % {'kind': kind, 'fn': fn})
+    else:
+      self.script.append(
+          'write_firmware_image("PACKAGE:%s", "%s");' % (fn, kind))
+
+  def WriteRawImage(self, partition, fn):
+    """Write the given package file into the given MTD partition."""
+    self.script.append(
+        ('assert(package_extract_file("%(fn)s", "/tmp/%(partition)s.img"),\n'
+         '       write_raw_image("/tmp/%(partition)s.img", "%(partition)s"),\n'
+         '       delete("/tmp/%(partition)s.img"));')
+        % {'partition': partition, 'fn': fn})
+
+  def SetPermissions(self, fn, uid, gid, mode):
+    """Set file ownership and permissions."""
+    self.script.append('set_perm(%d, %d, 0%o, "%s");' % (uid, gid, mode, fn))
+
+  def SetPermissionsRecursive(self, fn, uid, gid, dmode, fmode):
+    """Recursively set path ownership and permissions."""
+    self.script.append('set_perm_recursive(%d, %d, 0%o, 0%o, "%s");'
+                       % (uid, gid, dmode, fmode, fn))
+
+  def MakeSymlinks(self, symlink_list):
+    """Create symlinks, given a list of (dest, link) pairs."""
+    by_dest = {}
+    for d, l in symlink_list:
+      by_dest.setdefault(d, []).append(l)
+
+    for dest, links in sorted(by_dest.iteritems()):
+      cmd = ('symlink("%s", ' % (dest,) +
+             ",\0".join(['"' + i + '"' for i in sorted(links)]) + ");")
+      self.script.append(self._WordWrap(cmd))
+
+  def AppendExtra(self, extra):
+    """Append text verbatim to the output script."""
+    self.script.append(extra)
+
+  def AddToZip(self, input_zip, output_zip, input_path=None):
+    """Write the accumulated script to the output_zip file.  input_zip
+    is used as the source for the 'updater' binary needed to run
+    script.  If input_path is not None, it will be used as a local
+    path for the binary instead of input_zip."""
+
+    for p in sorted(self.mounts):
+      self.script.append('unmount("%s");' % (p,))
+
+    common.ZipWriteStr(output_zip, "META-INF/com/google/android/updater-script",
+                       "\n".join(self.script) + "\n")
+
+    if input_path is None:
+      data = input_zip.read("OTA/bin/updater")
+    else:
+      data = open(os.path.join(input_path, "updater")).read()
+    common.ZipWriteStr(output_zip, "META-INF/com/google/android/update-binary",
+                       data, perms=0755)