Added install utils (digest calculation)

Author: Jürgen Hermann

roundup/install_util.py

@@ -0,0 +1,104 @@
+#
+# Copyright (c) 2001 Bizar Software Pty Ltd (http://www.bizarsoftware.com.au/)
+# This module is free software, and you may redistribute it and/or modify
+# under the same terms as Python, so long as this copyright message and
+# disclaimer are retained in their original form.
+#
+# IN NO EVENT SHALL BIZAR SOFTWARE PTY LTD BE LIABLE TO ANY PARTY FOR
+# DIRECT, INDIRECT, SPECIAL, INCIDENTAL, OR CONSEQUENTIAL DAMAGES ARISING
+# OUT OF THE USE OF THIS CODE, EVEN IF THE AUTHOR HAS BEEN ADVISED OF THE
+# POSSIBILITY OF SUCH DAMAGE.
+#
+# BIZAR SOFTWARE PTY LTD SPECIFICALLY DISCLAIMS ANY WARRANTIES, INCLUDING,
+# BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS
+# FOR A PARTICULAR PURPOSE.  THE CODE PROVIDED HEREUNDER IS ON AN "AS IS"
+# BASIS, AND THERE IS NO OBLIGATION WHATSOEVER TO PROVIDE MAINTENANCE,
+# SUPPORT, UPDATES, ENHANCEMENTS, OR MODIFICATIONS.
+# 
+# $Id: install_util.py,v 1.1 2001-11-12 22:26:32 jhermann Exp $
+
+import os, sha
+
+
+def checkDigest(filename):
+    """Read file, check for valid fingerprint, return TRUE if ok"""
+    # open and read file
+    inp = open(filename, "r")
+    lines = inp.readlines()
+    inp.close()
+
+    # get fingerprint from last line
+    if lines[-1][:6] == "#SHA: ":
+        # handle .py/.sh comment
+        fingerprint = lines[-1][6:].strip()
+    elif lines[-1][:10] == "<!-- SHA: ":
+        # handle xml files
+        fingerprint = lines[-1][10:]
+        fingerprint = fingerprint.replace('-->', '')
+        fingerprint = fingerprint.strip()
+    else:
+        return 0
+    del lines[-1]
+
+    # calculate current digest
+    digest = sha.new()
+    for line in lines:
+        digest.update(line)
+
+    # compare current to stored digest
+    return fingerprint == digest.hexdigest()
+
+
+class DigestFile:
+    """ A class that you can use like open() and that calculates
+        and writes a SHA digest to the target file.
+    """
+
+    def __init__(self, filename):
+        self.filename = filename
+        self.digest = sha.new()
+        self.file = open(self.filename, "w")
+
+    def write(self, data):
+        self.file.write(data)
+        self.digest.update(data)
+
+    def close(self):
+        file, ext = os.path.splitext(self.filename)
+
+        if ext in [".xml", ".ent"]:
+            self.file.write("<!-- SHA: %s -->\n" % (self.digest.hexdigest(),))
+        elif ext in [".py", ".sh", ".conf", '']:
+            self.file.write("#SHA: %s\n" % (self.digest.hexdigest(),))
+
+        self.file.close()
+
+
+def test():
+    import sys
+
+    testdata = open(sys.argv[0], 'r').read()
+    testfile = "digest_test.py"
+
+    out = DigestFile(testfile)
+    out.write(testdata)
+    out.close()
+
+    assert checkDigest(testfile), "digest ok w/o modification"
+
+    mod = open(testfile, 'r+')
+    mod.seek(0)
+    mod.write('# changed!')
+    mod.close()
+
+    assert not checkDigest(testfile), "digest fails after modification"
+
+    os.remove(testfile)
+
+
+if __name__ == '__main__':
+    test()
+
+#
+# $Log: not supported by cvs2svn $
+