Move email_as_string function from crypto to helper module

The email_as_string function, and the related RFC3156_canonicalize
function, are now used by the ForwardCommand and are not specific
anymore to the crypto routine. So we move them to the global helper
module.

fix an import removal mistake while moving email_as_string function: StringIO was not only used by email_as_string

5 files changed, 63 insertions, 60 deletions

diff --git a/alot/commands/envelope.py b/alot/commands/envelope.py
index b67231b7..b90816d2 100644
--- a/alot/commands/envelope.py
+++ b/alot/commands/envelope.py
@@ -19,6 +19,7 @@ from alot import crypto
 from alot.commands import Command, registerCommand
 from alot.commands import globals
 from alot.helper import string_decode
+from alot.helper import email_as_string
 from alot.settings import settings
 from alot.utils.booleanaction import BooleanAction
 from alot.db.errors import DatabaseError
@@ -130,7 +131,7 @@ class SaveCommand(Command):
         # store mail locally
         # add Date header
         mail['Date'] = email.Utils.formatdate(localtime=True)
-        path = account.store_draft_mail(crypto.email_as_string(mail))
+        path = account.store_draft_mail(email_as_string(mail))
 
         msg = 'draft saved successfully'
 
@@ -201,7 +202,7 @@ class SendCommand(Command):
             try:
                 self.mail = self.envelope.construct_mail()
                 self.mail['Date'] = email.Utils.formatdate(localtime=True)
-                self.mail = crypto.email_as_string(self.mail)
+                self.mail = email_as_string(self.mail)
             except GPGProblem, e:
                 ui.clear_notify([clearme])
                 ui.notify(e.message, priority='error')
diff --git a/alot/commands/thread.py b/alot/commands/thread.py
index 04fadeeb..ca73c75f 100644
--- a/alot/commands/thread.py
+++ b/alot/commands/thread.py
@@ -21,7 +21,6 @@ from alot.commands.globals import MoveCommand
 from alot.commands.globals import CommandCanceled
 from alot.commands.envelope import SendCommand
 from alot import completion
-from alot import crypto
 from alot.db.utils import decode_header
 from alot.db.utils import encode_header
 from alot.db.utils import extract_headers
@@ -32,6 +31,7 @@ from alot.db.errors import DatabaseROError
 from alot.settings import settings
 from alot.helper import parse_mailcap_nametemplate
 from alot.helper import split_commandstring
+from alot.helper import email_as_string
 from alot.utils.booleanaction import BooleanAction
 from alot.completion import ContactsCompleter
 
@@ -315,7 +315,7 @@ class ForwardCommand(Command):
             original_mail = Message()
             original_mail.set_type('message/rfc822')
             original_mail['Content-Disposition'] = 'attachment'
-            original_mail.set_payload(crypto.email_as_string(mail))
+            original_mail.set_payload(email_as_string(mail))
             envelope.attach(Attachment(original_mail))
 
         # copy subject
diff --git a/alot/crypto.py b/alot/crypto.py
index 1270485d..4c74f1bf 100644
--- a/alot/crypto.py
+++ b/alot/crypto.py
@@ -4,41 +4,11 @@
 import re
 import os
 
-from email.generator import Generator
 from cStringIO import StringIO
 from alot.errors import GPGProblem, GPGCode
-from email.mime.multipart import MIMEMultipart
 import gpgme
 
 
-def email_as_string(mail):
-    """
-    Converts the given message to a string, without mangling "From" lines
-    (like as_string() does).
-
-    :param mail: email to convert to string
-    :rtype: str
-    """
-    fp = StringIO()
-    g = Generator(fp, mangle_from_=False, maxheaderlen=78)
-    g.flatten(mail)
-    as_string = RFC3156_canonicalize(fp.getvalue())
-
-    if isinstance(mail, MIMEMultipart):
-        # Get the boundary for later
-        boundary = mail.get_boundary()
-
-        # Workaround for http://bugs.python.org/issue14983:
-        # Insert a newline before the outer mail boundary so that other mail
-        # clients can verify the signature when sending an email which contains
-        # attachments.
-        as_string = re.sub(r'--(\r\n)--' + boundary,
-                           '--\g<1>\g<1>--' + boundary,
-                           as_string, flags=re.MULTILINE)
-
-    return as_string
-
-
 def _hash_algo_name(hash_algo):
     """
     Re-implements GPGME's hash_algo_name as long as pygpgme doesn't wrap that
@@ -85,27 +55,6 @@ def RFC3156_micalg_from_algo(hash_algo):
     return 'pgp-' + hash_algo.lower()
 
 
-def RFC3156_canonicalize(text):
-    """
-    Canonicalizes plain text (MIME-encoded usually) according to RFC3156.
-
-    This function works as follows (in that order):
-
-    1. Convert all line endings to \\\\r\\\\n (DOS line endings).
-    2. Ensure the text ends with a newline (\\\\r\\\\n).
-    3. Encode all occurences of "From " at the beginning of a line
-       to "From=20" in order to prevent other mail programs to replace
-       this with "> From" (to avoid MBox conflicts) and thus invalidate
-       the signature.
-
-    :param text: text to canonicalize (already encoded as quoted-printable)
-    :rtype: str
-    """
-    text = re.sub("\r?\n", "\r\n", text)
-    if not text.endswith("\r\n"):
-        text += "\r\n"
-    text = re.sub("^From ", "From=20", text, flags=re.MULTILINE)
-    return text
 
 
 def get_key(keyid, validate=False, encrypt=False, sign=False):
diff --git a/alot/db/envelope.py b/alot/db/envelope.py
index a9c4fc7c..6550baeb 100644
--- a/alot/db/envelope.py
+++ b/alot/db/envelope.py
@@ -184,7 +184,7 @@ class Envelope(object):
             inner_msg = textpart
 
         if self.sign:
-            plaintext = crypto.email_as_string(inner_msg)
+            plaintext = helper.email_as_string(inner_msg)
             logging.debug('signing plaintext: ' + plaintext)
 
             try:
@@ -229,7 +229,7 @@ class Envelope(object):
             unencrypted_msg = inner_msg
 
         if self.encrypt:
-            plaintext = crypto.email_as_string(unencrypted_msg)
+            plaintext = helper.email_as_string(unencrypted_msg)
             logging.debug('encrypting plaintext: ' + plaintext)
 
             try:
diff --git a/alot/helper.py b/alot/helper.py
index 6eceeed9..fb95f706 100644
--- a/alot/helper.py
+++ b/alot/helper.py
@@ -11,16 +11,18 @@ import email
 import mimetypes
 import os
 import re
+from email.generator import Generator
 from email.mime.audio import MIMEAudio
 from email.mime.base import MIMEBase
 from email.mime.image import MIMEImage
 from email.mime.text import MIMEText
+from email.mime.multipart import MIMEMultipart
 import urwid
 import magic
 from twisted.internet import reactor
 from twisted.internet.protocol import ProcessProtocol
 from twisted.internet.defer import Deferred
-import StringIO
+from cStringIO import StringIO
 import logging
 
 
@@ -337,8 +339,8 @@ def call_cmd_async(cmdlist, stdin=None, env=None):
     class _EverythingGetter(ProcessProtocol):
         def __init__(self, deferred):
             self.deferred = deferred
-            self.outBuf = StringIO.StringIO()
-            self.errBuf = StringIO.StringIO()
+            self.outBuf = StringIO()
+            self.errBuf = StringIO()
             self.outReceived = self.outBuf.write
             self.errReceived = self.errBuf.write
 
@@ -589,3 +591,54 @@ def mailto_to_envelope(mailto_str):
     from alot.db.envelope import Envelope
     headers, body = parse_mailto(mailto_str)
     return Envelope(bodytext=body, headers=headers)
+
+
+def RFC3156_canonicalize(text):
+    """
+    Canonicalizes plain text (MIME-encoded usually) according to RFC3156.
+
+    This function works as follows (in that order):
+
+    1. Convert all line endings to \\\\r\\\\n (DOS line endings).
+    2. Ensure the text ends with a newline (\\\\r\\\\n).
+    3. Encode all occurences of "From " at the beginning of a line
+       to "From=20" in order to prevent other mail programs to replace
+       this with "> From" (to avoid MBox conflicts) and thus invalidate
+       the signature.
+
+    :param text: text to canonicalize (already encoded as quoted-printable)
+    :rtype: str
+    """
+    text = re.sub("\r?\n", "\r\n", text)
+    if not text.endswith("\r\n"):
+        text += "\r\n"
+    text = re.sub("^From ", "From=20", text, flags=re.MULTILINE)
+    return text
+
+
+def email_as_string(mail):
+    """
+    Converts the given message to a string, without mangling "From" lines
+    (like as_string() does).
+
+    :param mail: email to convert to string
+    :rtype: str
+    """
+    fp = StringIO()
+    g = Generator(fp, mangle_from_=False, maxheaderlen=78)
+    g.flatten(mail)
+    as_string = RFC3156_canonicalize(fp.getvalue())
+
+    if isinstance(mail, MIMEMultipart):
+        # Get the boundary for later
+        boundary = mail.get_boundary()
+
+        # Workaround for http://bugs.python.org/issue14983:
+        # Insert a newline before the outer mail boundary so that other mail
+        # clients can verify the signature when sending an email which contains
+        # attachments.
+        as_string = re.sub(r'--(\r\n)--' + boundary,
+                           '--\g<1>\g<1>--' + boundary,
+                           as_string, flags=re.MULTILINE)
+
+    return as_string