tiny step towards future port to Py3.4

Author: 8go

README.md

@@ -46,7 +46,7 @@ Below a sample screenshot. More screenshots [here](screenshots).
 # Build and runtime requirements
 
   * Use of passphrases must have been already enabled on your [Trezor](https://www.trezor.io) device.
-  * [Python](https://www.python.org/)
+  * [Python](https://www.python.org/) v2.7
   * PyCrypto
   * PyQt4
   * [trezorlib from python-trezor](https://github.com/trezor/python-trezor)
@@ -73,7 +73,7 @@ Run-time command line options are
 
 ```
 TrezorSymmetricFileEncryption.py [-v] [-h] [-l <level>] [-t] [-e | -o | -d | -m | -n] [-2] [-s] [-w] [-p <passphrase>] [-r] [-R] <files>
-    -v, --verion
+    -v, --version
             print the version number
     -h, --help
             print short help text
@@ -266,7 +266,7 @@ single-file-executablefile.
 - - -
 **Question:** In which language is TrezorSymmetricFileEncryption written?
 
-**Answer:** [Python](https://www.python.org/).
+**Answer:** [Python](https://www.python.org/) 2.7. It wil currently not run on Python 3.
 - - -
 **Question:** Do I need to have a [Trezor](https://www.trezor.io/) in
 order to use TrezorSymmetricFileEncryption?

TrezorSymmetricFileEncryption.py

@@ -10,6 +10,10 @@
 
 '''
 
+from __future__ import absolute_import
+from __future__ import division
+from __future__ import print_function
+
 import sys
 import logging
 import getpass
@@ -46,17 +50,17 @@ def callback_ButtonRequest(self, msg):
 
 	def callback_PassphraseRequest(self, msg):
 		if self.passphrase is not None:
-			return proto.PassphraseAck(passphrase=unicode(self.passphrase))
+			return proto.PassphraseAck(passphrase=str(self.passphrase))
 
 		if self.readpassphrasefromstdin:
 			# read passphrase from stdin
 			try:
 				passphrase = getpass.getpass("Please enter passphrase: ")
-				passphrase = unicode(passphrase)
+				passphrase = str(passphrase)
 			except KeyboardInterrupt:
 				sys.stderr.write("\nKeyboard interrupt: passphrase not read. Aborting.\n")
 				sys.exit(3)
-			except Exception, e:
+			except Exception as e:
 				sys.stderr.write("Critical error: Passphrase not read. Aborting. (%s)" % e)
 				sys.exit(3)
 		else:
@@ -65,22 +69,22 @@ def callback_PassphraseRequest(self, msg):
 				sys.exit(3)
 			else:
 				passphrase = dialog.passphraseEdit.text()
-				passphrase = unicode(passphrase)
+				passphrase = str(passphrase)
 
 		return proto.PassphraseAck(passphrase=passphrase)
 
 	def callback_PinMatrixRequest(self, msg):
 		if self.readpinfromstdin:
 			# read PIN from stdin
-			print "                  7  8  9"
-			print "                  4  5  6"
-			print "                  1  2  3"
+			print("                  7  8  9")
+			print("                  4  5  6")
+			print("                  1  2  3")
 			try:
 				pin = getpass.getpass("Please enter PIN: ")
 			except KeyboardInterrupt:
 				sys.stderr.write("\nKeyboard interrupt: PIN not read. Aborting.\n")
 				sys.exit(7)
-			except Exception, e:
+			except Exception as e:
 				sys.stderr.write("Critical error: PIN not read. Aborting. (%s)" % e)
 				sys.exit(7)
 		else:
@@ -234,7 +238,7 @@ def showGui(trezor, settings, fileMap, logger):
 try:
 	trezorChooser = TrezorChooser()
 	trezor = trezorChooser.getDevice()
-except (ConnectionError, RuntimeError), e:
+except (ConnectionError, RuntimeError) as e:
 	processing.reportLogging("Connection to Trezor failed: %s" % e.message,
 		logging.CRITICAL, "Trezor Error", settings, logger)
 	sys.exit(1)

basics.py

@@ -1,3 +1,7 @@
+from __future__ import absolute_import
+from __future__ import division
+from __future__ import print_function
+
 import logging
 
 # file extension for encrypted files with plaintext filename
@@ -7,7 +11,7 @@
 TSFEFILEFORMATVERSION = 1
 
 # Name of software version, must be less than 16 long
-TSFEVERSION = "v0.4.3"
+TSFEVERSION = "v0.5.0"
 
 # Date of software version, only used in GUI
 TSFEVERSIONTEXT = "May 2017"

comments.md

@@ -72,3 +72,35 @@ The Trezor chip is slow. It takes the Trezor (model 1) device about  75 seconds
 - [x] make the image smaller on main window
 - [x] more Testing
 - [ ] get help with getting the word out, anyone wants to spread the word on Twitter, Reddit, with Trezor, Facebook, etc.?
+
+# Migrating to Python3
+
+Doing only Python 2.7 or only 3.4 is okay, but making both work on the same code base is cumbersome.
+The combination would be Py2.7 | Py3.4 + PyQt4.11.
+
+* Basic description of the problem is [here](https://docs.python.org/3/howto/pyporting.html) with some pointers as how to start.
+* [2to3](https://docs.python.org/3/library/2to3.html) has been done. It was trivial. Only a few lines of code changed.
+* [modernize](https://python-modernize.readthedocs.io/en/latest/) has been done. Again, it was just suggesting a few new lines related to the `range` operator.
+* [futurize](http://python-future.org/automatic_conversion.html) was also done. It suggested only a few `import` lines. The 3 lines were added to all .py files.
+```
+from __future__ import absolute_import
+from __future__ import division
+from __future__ import print_function
+```
+* Changes related to GUI are:
+PyQt4.11 for Py3.4 does not have class QString. It expects unicode objects. Simple hacks like
+the folowing are not likely to work.
+```
+try:
+    from PyQt4.QtCore import QString
+except ImportError:
+    # we are using Python3 so QString is not defined
+    QString = type("")
+```
+* Since Py2.7 does not have bytes and handles everything as strings. A common layer would have to be introduced
+that simulates bytes on Py2.7. Some good code starting points can be found at
+[python3porting.com](http://python3porting.com/problems.html#bytes-strings-and-unicode).
+* In Debian 9 Py2 will remain the default Py version, so Py2.7 does not seem to be going away.
+
+In short, for the time being it does not seem worth it to add code to make it run on both 2.7 and 3.4.
+It seems one can wait until 2.7 becomes outdated and then port to 3.5, breaking and leaving 2.7 behind.

dialogs.py

@@ -1,3 +1,7 @@
+from __future__ import absolute_import
+from __future__ import division
+from __future__ import print_function
+
 import os
 import os.path
 import logging

encoding.py

@@ -1,15 +1,18 @@
-import struct
-
-from PyQt4 import QtCore
+from __future__ import absolute_import
+from __future__ import division
+from __future__ import print_function
 
 import os
 import os.path
 import random
+import struct
+
+from PyQt4 import QtCore
 
 
-def q2s(s):
+def q2s(q):
 	"""Convert QString to UTF-8 string object"""
-	return str(s.toUtf8())
+	return str(q.toUtf8())
 
 
 def s2q(s):
@@ -33,21 +36,21 @@ class Magic(object):
 	for keys.
 	"""
 
-	headerStr = "TSFE"
+	headerStr = b'TSFE'
 	hdr = u("!I", headerStr)
 
 	# first level encryption
 	# unlock key for first level AES encryption, key from Trezor, en/decryption on PC
-	levelOneNode = [hdr, u("!I", "DEC1")]
+	levelOneNode = [hdr, u("!I", b'DEC1')]
 	levelOneKey = "Decrypt file for first time?"  # string to derive wrapping key from
 
 	# second level encryption
 	# second level AES encryption, de/encryption on trezor device
-	levelTwoNode = [hdr, u("!I", "DEC2")]
+	levelTwoNode = [hdr, u("!I", b'DEC2')]
 	levelTwoKey = "Decrypt file for second time?"
 
 	# only used for filename encryption (no confirm button click desired)
-	fileNameNode = [hdr, u("!I", "FLNM")]  # filename encryption for filename obfuscation
+	fileNameNode = [hdr, u("!I", b'FLNM')]  # filename encryption for filename obfuscation
 	fileNameKey = "Decrypt filename only?"
 
 

file_map.py

@@ -1,3 +1,7 @@
+from __future__ import absolute_import
+from __future__ import division
+from __future__ import print_function
+
 import os
 import os.path
 import sys
@@ -80,7 +84,7 @@ def createDecFile(self, fname):
 					"Change file permissions and try again." % (fname))
 
 		self.loadBlobFromEncFile(originalFilename)
-		with open(fname, 'w+b') as f:
+		with open(fname, "wb") as f:
 			s = len(self.blob)
 			f.write(self.blob)
 			if f.tell() != s:
@@ -118,7 +122,7 @@ def loadBlobFromEncFile(self, fname):
 
 		@throws IOError: if reading file failed
 		"""
-		with open(fname, 'rb') as f:
+		with open(fname, "rb") as f:
 			header = f.read(len(Magic.headerStr))
 			if header != Magic.headerStr:
 				raise IOError("Bad header in storage file")
@@ -202,7 +206,7 @@ def createEncFile(self, fname, obfuscate, twice, outerKey=None, outerIv=None, in
 		@param innerIv: see outerKey
 		"""
 
-		with open(fname, 'rb') as f:
+		with open(fname, "rb") as f:
 			# Size 0 will read the ENTIRE file into memory!
 			# File is open read-only
 			# mmap does not implement __exit__ so we cannot use "with mmap... as m:"
@@ -427,15 +431,15 @@ def encryptOnTrezorDevice(self, blob, keystring, innerIv=None):
 			try:
 				encrypted += self.trezor.encrypt_keyvalue(Magic.levelTwoNode,
 					ukeystring, padded, ask_on_encrypt=False, ask_on_decrypt=first, iv=rndBlock)
-			except Exception, e:
+			except Exception as e:
 				self.logger.critical('Trezor failed. (%s)', e)
 				raise
 			first = False
 			curr += 1
 			if self.logger.getEffectiveLevel() == logging.DEBUG:
-				print >> sys.stderr, "\rencrypting block", curr, "of", max,
+				sys.stderr.write("\rencrypting block %d of %d" % (curr, max),)
 		if self.logger.getEffectiveLevel() == logging.DEBUG:
-			print >> sys.stderr, "done"
+			sys.stderr.write(" --> done\n")
 		ret = rndBlock + encrypted
 		self.logger.debug("Trezor encryption: plain-size = %d, encrypted-size = %d", len(blob),  len(ret))
 		self.logger.debug('time leaving encryptOnTrezorDevice: %s', datetime.datetime.now())
@@ -453,7 +457,7 @@ def decryptOnTrezorDevice(self, encryptedblob, keystring):
 				"Decrypting each Megabyte on the Trezor (model 1) takes about 75 seconds, "
 				"or 0.8MB/min. This file will take about %d minutes. If you want to "
 				"en/decrypt fast the next time around, remove the `-2` or `--twice` "
-				"option when you encrypt a file.", len(encryptedblob) / 819200)
+				"option when you encrypt a file.", len(encryptedblob) // 819200)
 		self.logger.debug('time entering decryptOnTrezorDevice: %s', datetime.datetime.now())
 		ukeystring = keystring.decode("utf-8")
 		iv, encryptedblob = encryptedblob[:BLOCKSIZE], encryptedblob[BLOCKSIZE:]
@@ -469,16 +473,16 @@ def decryptOnTrezorDevice(self, encryptedblob, keystring):
 			try:
 				plain = self.trezor.decrypt_keyvalue(Magic.levelTwoNode,
 					ukeystring, junk, ask_on_encrypt=False, ask_on_decrypt=first, iv=iv)
-			except Exception, e:
+			except Exception as e:
 				self.logger.critical('Trezor failed. (%s)', e)
 				raise
 			first = False
 			blob += Padding(BLOCKSIZE).unpad(plain)
 			curr += 1
 			if self.logger.getEffectiveLevel() == logging.DEBUG:
-				print >> sys.stderr, "\rdecrypting block", curr, "of", max,
+				sys.stderr.write("\rdecrypting block %d of %d" % (curr, max),)
 		if self.logger.getEffectiveLevel() == logging.DEBUG:
-			print >> sys.stderr, "done"
+			sys.stderr.write(" --> done\n")
 		self.logger.debug("Trezor decryption: encrypted-size = %d, plain-size = %d",
 			len(encryptedblob),  len(blob))
 		if len(blob) == 0: