buildmimetree.py: rework of file io

[etc/neomutt.git] / .config / neomutt / buildmimetree.py

diff --git a/.config/neomutt/buildmimetree.py b/.config/neomutt/buildmimetree.py
index 00526327ddca23a14446c9901d214eb368b6b2fe..32fc17c005b613055a3dc42fdb8f744f148652e4 100755 (executable)
--- a/.config/neomutt/buildmimetree.py
+++ b/.config/neomutt/buildmimetree.py
@@ -9,7 +9,8 @@
 #     set my_mdwn_extensions="extra,admonition,codehilite,sane_lists,smarty"
 #     macro compose B "\
 #       <enter-command> source '$my_confdir/buildmimetree.py \
 #     set my_mdwn_extensions="extra,admonition,codehilite,sane_lists,smarty"
 #     macro compose B "\
 #       <enter-command> source '$my_confdir/buildmimetree.py \

-#       --tempdir $tempdir --extensions $my_mdwn_extensions|'<enter>\
+#       --tempdir $tempdir --extensions $my_mdwn_extensions \
+#       --css-file $my_confdir/htmlmail.css |'<enter>\

 #       <enter-command> sourc e \$my_mdwn_postprocess_cmd_file<enter>\
 #     " "Convert message into a modern MIME tree with inline images"
 #
 #       <enter-command> sourc e \$my_mdwn_postprocess_cmd_file<enter>\
 #     " "Convert message into a modern MIME tree with inline images"
 #


@@ -21,6 +22,7 @@
 # Requirements:
 #   - python3
 #   - python3-markdown
 # Requirements:
 #   - python3
 #   - python3-markdown

+#   - python3-beautifulsoup4

 # Optional:
 #   - pytest
 #   - Pynliner, provides --css-file and thus inline styling of HTML output
 # Optional:
 #   - pytest
 #   - Pynliner, provides --css-file and thus inline styling of HTML output


@@ -34,14 +36,19 @@
 #
 
 import sys
 #
 
 import sys

+import os.path

 import pathlib
 import markdown
 import tempfile
 import argparse
 import re
 import mimetypes
 import pathlib
 import markdown
 import tempfile
 import argparse
 import re
 import mimetypes

+import bs4
+import xml.etree.ElementTree as etree
+import io

 from collections import namedtuple, OrderedDict
 from markdown.extensions import Extension
 from collections import namedtuple, OrderedDict
 from markdown.extensions import Extension

+from markdown.blockprocessors import BlockProcessor

 from markdown.inlinepatterns import ImageInlineProcessor, IMAGE_LINK_RE
 from email.utils import make_msgid
 from urllib import request
 from markdown.inlinepatterns import ImageInlineProcessor, IMAGE_LINK_RE
 from email.utils import make_msgid
 from urllib import request


@@ -61,6 +68,7 @@ def parse_cli_args(*args, **kwargs):
 
     parser.add_argument(
         "--extensions",
 
     parser.add_argument(
         "--extensions",

+        metavar="EXT[,EXT[,EXT]]",

         type=str,
         default="",
         help="Markdown extension to use (comma-separated list)",
         type=str,
         default="",
         help="Markdown extension to use (comma-separated list)",


@@ -69,7 +77,9 @@ def parse_cli_args(*args, **kwargs):
     if _PYNLINER:
         parser.add_argument(
             "--css-file",
     if _PYNLINER:
         parser.add_argument(
             "--css-file",

+            metavar="FILE",

             type=pathlib.Path,
             type=pathlib.Path,

+            default=os.devnull,

             help="CSS file to merge with the final HTML",
         )
     else:
             help="CSS file to merge with the final HTML",
         )
     else:


@@ -89,22 +99,26 @@ def parse_cli_args(*args, **kwargs):
         except ValueError:
             pass
 
         except ValueError:
             pass
 

-        raise ValueError(f"Must be a positive integer")
+        raise ValueError("Must be a positive integer")

 
     parser.add_argument(
         "--max-number-other-attachments",
 
     parser.add_argument(
         "--max-number-other-attachments",

+        metavar="INTEGER",

         type=positive_integer,
         type=positive_integer,

-        help="Make related content be sibling to HTML parts only",
+        default=20,
+        help="Maximum number of other attachments to expect",

     )
 
     parser.add_argument(
         "--only-build",
     )
 
     parser.add_argument(
         "--only-build",

+        "--just-build",

         action="store_true",
         help="Only build, don't send the message",
     )
 
     parser.add_argument(
         "--tempdir",
         action="store_true",
         help="Only build, don't send the message",
     )
 
     parser.add_argument(
         "--tempdir",

+        metavar="DIR",

         type=pathlib.Path,
         help="Specify temporary directory to use for attachments",
     )
         type=pathlib.Path,
         help="Specify temporary directory to use for attachments",
     )


@@ -115,6 +129,19 @@ def parse_cli_args(*args, **kwargs):
         help="Turn on debug logging of commands generated to stderr",
     )
 
         help="Turn on debug logging of commands generated to stderr",
     )
 

+    parser.add_argument(
+        "--debug-walk",
+        action="store_true",
+        help="Turn on debugging to stderr of the MIME tree walk",
+    )
+
+    parser.add_argument(
+        "--dump-html",
+        metavar="FILE",
+        type=pathlib.Path,
+        help="Write the generated HTML to the file",
+    )
+

     subp = parser.add_subparsers(help="Sub-command parsers", dest="mode")
     massage_p = subp.add_parser(
         "massage", help="Massaging phase (internal use)"
     subp = parser.add_subparsers(help="Sub-command parsers", dest="mode")
     massage_p = subp.add_parser(
         "massage", help="Massaging phase (internal use)"


@@ -123,19 +150,13 @@ def parse_cli_args(*args, **kwargs):
     massage_p.add_argument(
         "--write-commands-to",
         "-o",
     massage_p.add_argument(
         "--write-commands-to",
         "-o",

-        metavar="PATH",
+        metavar="FILE",

         dest="cmdpath",
         type=pathlib.Path,
         required=True,
         help="Temporary file path to write commands to",
     )
 
         dest="cmdpath",
         type=pathlib.Path,
         required=True,
         help="Temporary file path to write commands to",
     )
 

-    massage_p.add_argument(
-        "--debug-walk",
-        action="store_true",
-        help="Turn on debugging to stderr of the MIME tree walk",
-    )
-

     massage_p.add_argument(
         "MAILDRAFT",
         nargs="?",
     massage_p.add_argument(
         "MAILDRAFT",
         nargs="?",


@@ -146,7 +167,164 @@ def parse_cli_args(*args, **kwargs):
     return parser.parse_args(*args, **kwargs)
 
 
     return parser.parse_args(*args, **kwargs)
 
 

-# [ MARKDOWN WRAPPING ] #######################################################
+# [ FILE I/O HANDLING ] #######################################################
+
+
+class File:
+    def __init__(self, path=None, mode="r", content=None, **kwargs):
+        if path:
+            if content:
+                raise RuntimeError("Cannot specify path and content for File")
+
+            self._path = (
+                path if isinstance(path, pathlib.Path) else pathlib.Path(path)
+            )
+        else:
+            self._path = None
+
+        if content and not re.search(r"[r+]", mode):
+            raise RuntimeError("Cannot specify content without read mode")
+
+        self._rcache = [content] if content else []
+        self._wcache = []
+        self._mode = mode
+        self._kwargs = kwargs
+        self._file = None
+
+    def open(self):
+        if self._path:
+            self._file = open(self._path, self._mode, **self._kwargs)
+        elif "b" in self._mode:
+            self._file = io.BytesIO()
+        else:
+            self._file = io.StringIO()
+
+    def __enter__(self):
+        self.open()
+        return self
+
+    def __exit__(self, exc_type, exc_val, exc_tb):
+        self.close()
+
+    def close(self):
+        self._file.close()
+        self._file = None
+        self._rcache = self._wcache
+
+    def _get_rcache(self):
+        return (b"" if "b" in self._mode else "").join(self._rcache)
+
+    def _get_wcache(self):
+        return (b"" if "b" in self._mode else "").join(self._wcache)
+
+    def _add_to_rcache(self, s):
+        self._rcache.append(s)
+
+    def _add_to_wcache(self, s):
+        self._wcache.append(s)
+
+    def read(self, *, cache=True):
+        if cache and self._rcache:
+            return self._get_rcache()
+
+        if not self._file:
+            with self as f:
+                return f.read(cache=cache)
+
+        self._file.seek(0)
+        if cache:
+            self._add_to_rcache(self._file.read())
+            return self._get_rcache()
+        else:
+            return self._file.read()
+
+    def write(self, s, *, cache=True):
+        if not self._file:
+            with self as f:
+                return f.write(s, cache=cache)
+
+        self._file.seek(0)
+        self._rcache = self._wcache
+
+        if cache:
+            self._add_to_wcache(s)
+
+        written = self._file.write(s)
+        self._file.flush()
+        return written
+
+    path = property(lambda s: s._path)
+
+    def __repr__(self):
+        return (
+            f'<File path={self._path or "(buffered)"} open={bool(self._file)} '
+            f"rcache={sum(len(c) for c in self._rcache) if self._rcache is not None else False} "
+            f"wcache={sum(len(c) for c in self._wcache) if self._wcache is not None else False}>"
+        )
+
+
+class FileFactory:
+    def __init__(self):
+        self._files = []
+
+    def __call__(self, path=None, mode="r", content=None, **kwargs):
+        f = File(path, mode, content, **kwargs)
+        self._files.append(f)
+        return f
+
+    def __len__(self):
+        return self._files.__len__()
+
+    def pop(self, idx=-1):
+        return self._files.pop(idx)
+
+    def __getitem__(self, idx):
+        return self._files.__getitem__(idx)
+
+    def __contains__(self, f):
+        return self._files.__contains__(f)
+
+
+class FakeFileFactory(FileFactory):
+    def __init__(self):
+        super().__init__()
+        self._paths2files = OrderedDict()
+
+    def __call__(self, path=None, mode="r", content=None, **kwargs):
+        if path in self._paths2files:
+            return self._paths2files[path]
+
+        f = super().__call__(None, mode, content, **kwargs)
+        self._paths2files[path] = f
+
+        mypath = path
+
+        class FakeFile(File):
+            path = mypath
+
+        # this is quality Python! We do this so that the fake file, which has
+        # no path, fake-pretends to have a path for testing purposes.
+
+        f.__class__ = FakeFile
+        return f
+
+    def __getitem__(self, path):
+        return self._paths2files.__getitem__(path)
+
+    def get(self, path, default):
+        return self._paths2files.get(path, default)
+
+    def pop(self, last=True):
+        return self._paths2files.popitem(last)
+
+    def __repr__(self):
+        return (
+            f"<FakeFileFactory nfiles={len(self._files)} "
+            f"paths={len(self._paths2files)}>"
+        )
+
+
+# [ IMAGE HANDLING ] ##########################################################

 
 
 InlineImageInfo = namedtuple(
 
 
 InlineImageInfo = namedtuple(


@@ -154,11 +332,43 @@ InlineImageInfo = namedtuple(
 )
 
 
 )
 
 

+class ImageRegistry:
+    def __init__(self):
+        self._images = OrderedDict()
+
+    def register(self, path, description=None):
+        # path = str(pathlib.Path(path).expanduser())
+        path = os.path.expanduser(path)
+        if path.startswith("/"):
+            path = f"file://{path}"
+        cid = make_msgid()[1:-1]
+        self._images[path] = InlineImageInfo(cid, description)
+        return cid
+
+    def __iter__(self):
+        return self._images.__iter__()
+
+    def __getitem__(self, idx):
+        return self._images.__getitem__(idx)
+
+    def __len__(self):
+        return self._images.__len__()
+
+    def items(self):
+        return self._images.items()
+
+    def __repr__(self):
+        return f"<ImageRegistry(items={len(self._images)})>"
+
+    def __str__(self):
+        return self._images.__str__()
+
+

 class InlineImageExtension(Extension):
     class RelatedImageInlineProcessor(ImageInlineProcessor):
 class InlineImageExtension(Extension):
     class RelatedImageInlineProcessor(ImageInlineProcessor):

-        def __init__(self, re, md, ext):
+        def __init__(self, re, md, registry):

             super().__init__(re, md)
             super().__init__(re, md)

-            self._ext = ext
+            self._registry = registry

 
         def handleMatch(self, m, data):
             el, start, end = super().handleMatch(m, data)
 
         def handleMatch(self, m, data):
             el, start, end = super().handleMatch(m, data)


@@ -166,60 +376,62 @@ class InlineImageExtension(Extension):
                 src = el.attrib["src"]
                 if "://" not in src or src.startswith("file://"):
                     # We only inline local content
                 src = el.attrib["src"]
                 if "://" not in src or src.startswith("file://"):
                     # We only inline local content

-                    cid = self._ext.get_cid_for_image(el.attrib)
+                    cid = self._registry.register(
+                        el.attrib["src"],
+                        el.attrib.get("title", el.attrib.get("alt")),
+                    )

                     el.attrib["src"] = f"cid:{cid}"
             return el, start, end
 
                     el.attrib["src"] = f"cid:{cid}"
             return el, start, end
 

-    def __init__(self):
+    def __init__(self, registry):

         super().__init__()
         super().__init__()

-        self._images = OrderedDict()
+        self._image_registry = registry
+
+    INLINE_PATTERN_NAME = "image_link"

 
     def extendMarkdown(self, md):
         md.registerExtension(self)
         inline_image_proc = self.RelatedImageInlineProcessor(
 
     def extendMarkdown(self, md):
         md.registerExtension(self)
         inline_image_proc = self.RelatedImageInlineProcessor(

-            IMAGE_LINK_RE, md, self
+            IMAGE_LINK_RE, md, self._image_registry

         )
         )

-        md.inlinePatterns.register(inline_image_proc, "image_link", 150)
-
-    def get_cid_for_image(self, attrib):
-        msgid = make_msgid()[1:-1]
-        path = attrib["src"]
-        if path.startswith("/"):
-            path = f"file://{path}"
-        self._images[path] = InlineImageInfo(
-            msgid, attrib.get("title", attrib.get("alt"))
+        md.inlinePatterns.register(
+            inline_image_proc, InlineImageExtension.INLINE_PATTERN_NAME, 150

         )
         )

-        return msgid
-
-    def get_images(self):
-        return self._images

 
 
 def markdown_with_inline_image_support(
 
 
 def markdown_with_inline_image_support(

-    text, *, extensions=None, extension_configs=None
+    text,
+    *,
+    mdwn=None,
+    image_registry=None,
+    extensions=None,
+    extension_configs=None,

 ):
 ):

-    inline_image_handler = InlineImageExtension()
+    registry = (
+        image_registry if image_registry is not None else ImageRegistry()
+    )
+    inline_image_handler = InlineImageExtension(registry=registry)

     extensions = extensions or []
     extensions.append(inline_image_handler)
     mdwn = markdown.Markdown(
         extensions=extensions, extension_configs=extension_configs
     )
     extensions = extensions or []
     extensions.append(inline_image_handler)
     mdwn = markdown.Markdown(
         extensions=extensions, extension_configs=extension_configs
     )

-    htmltext = mdwn.convert(text)

 
 

-    images = inline_image_handler.get_images()
+    htmltext = mdwn.convert(text)

 
     def replace_image_with_cid(matchobj):
         for m in (matchobj.group(1), f"file://{matchobj.group(1)}"):
 
     def replace_image_with_cid(matchobj):
         for m in (matchobj.group(1), f"file://{matchobj.group(1)}"):

-            if m in images:
-                return f"(cid:{images[m].cid}"
+            if m in registry:
+                return f"(cid:{registry[m].cid}"

         return matchobj.group(0)
 
     text = re.sub(r"\(([^)\s]+)", replace_image_with_cid, text)
         return matchobj.group(0)
 
     text = re.sub(r"\(([^)\s]+)", replace_image_with_cid, text)

-    return text, htmltext, images
+    return text, htmltext, registry, mdwn

 
 
 # [ CSS STYLING ] #############################################################
 
 
 
 # [ CSS STYLING ] #############################################################
 

+

 try:
     import pynliner
 
 try:
     import pynliner
 


@@ -250,6 +462,68 @@ def apply_styling(html, css):
     )
 
 
     )
 
 

+# [ QUOTE HANDLING ] ##########################################################
+
+
+class QuoteToAdmonitionExtension(Extension):
+    class EmailQuoteBlockProcessor(BlockProcessor):
+        RE = re.compile(r"(?:^|\n)>\s*(.*)")
+
+        def __init__(self, parser):
+            super().__init__(parser)
+            self._title = None
+
+        def test(self, parent, blocks):
+            if markdown.util.nearing_recursion_limit():
+                return False
+
+            lines = blocks.splitlines()
+            if len(lines) < 2:
+                if not self._title:
+                    return False
+
+                elif not self.RE.search(lines[0]):
+                    return False
+
+                return len(lines) > 0
+
+            elif not self.RE.search(lines[0]) and self.RE.search(lines[1]):
+                return True
+
+            elif self._title and self.RE.search(lines[1]):
+                return True
+
+            return False
+
+        def run(self, parent, blocks):
+            quotelines = blocks.pop(0).splitlines()
+
+            cont = bool(self._title)
+            if not self.RE.search(quotelines[0]):
+                self._title = quotelines.pop(0)
+
+            admonition = etree.SubElement(parent, "div")
+            admonition.set(
+                "class", f"admonition quote{' continued' if cont else ''}"
+            )
+            self.parser.parseChunk(admonition, self._title)
+
+            admonition[0].set("class", "admonition-title")
+            self.parser.parseChunk(
+                admonition, "\n".join(self.clean(line) for line in quotelines)
+            )
+
+        @classmethod
+        def clean(klass, line):
+            m = klass.RE.match(line)
+            return m.group(1) if m else line
+
+    def extendMarkdown(self, md):
+        md.registerExtension(self)
+        email_quote_proc = self.EmailQuoteBlockProcessor(md.parser)
+        md.parser.blockprocessors.register(email_quote_proc, "emailquote", 25)
+
+

 # [ PARTS GENERATION ] ########################################################
 
 
 # [ PARTS GENERATION ] ########################################################
 
 


@@ -279,16 +553,11 @@ class Multipart(
         return hash(str(self.subtype) + "".join(str(self.children)))
 
 
         return hash(str(self.subtype) + "".join(str(self.children)))
 
 

-def filewriter_fn(path, content, mode="w", **kwargs):
-    with open(path, mode, **kwargs) as out_f:
-        out_f.write(content)
-
-

 def collect_inline_images(
 def collect_inline_images(

-    images, *, tempdir=None, filewriter_fn=filewriter_fn
+    image_registry, *, tempdir=None, filefactory=FileFactory()

 ):
     relparts = []
 ):
     relparts = []

-    for path, info in images.items():
+    for path, info in image_registry.items():

         if path.startswith("cid:"):
             continue
 
         if path.startswith("cid:"):
             continue
 


@@ -299,55 +568,181 @@ def collect_inline_images(
         tempfilename = tempfile.mkstemp(prefix="img", suffix=ext, dir=tempdir)
         path = pathlib.Path(tempfilename[1])
 
         tempfilename = tempfile.mkstemp(prefix="img", suffix=ext, dir=tempdir)
         path = pathlib.Path(tempfilename[1])
 

-        filewriter_fn(path, data.read(), "w+b")
+        with filefactory(path, "w+b") as out_f:
+            out_f.write(data.read())

 
 

+        # filewriter_fn(path, data.read(), "w+b")
+
+        desc = (
+            f'Inline image: "{info.desc}"'
+            if info.desc
+            else f"Inline image {str(len(relparts)+1)}"
+        )

         relparts.append(
         relparts.append(

-            Part(
-                *mimetype.split("/"),
-                path,
-                cid=info.cid,
-                desc=f"Image: {info.desc}",
-            )
+            Part(*mimetype.split("/"), path, cid=info.cid, desc=desc)

         )
 
     return relparts
 
 
         )
 
     return relparts
 
 

+EMAIL_SIG_SEP = "\n-- \n"
+HTML_SIG_MARKER = "=htmlsig "
+
+
+def make_html_doc(body, sig=None):
+    ret = (
+        "<!DOCTYPE html>\n"
+        "<html>\n"
+        "<head>\n"
+        '<meta http-equiv="content-type" content="text/html; charset=UTF-8">\n'  # noqa: E501
+        '<meta name="viewport" content="width=device-width, initial-scale=1.0">\n'  # noqa: E501
+        "</head>\n"
+        "<body>\n"
+        f"{body}\n"
+    )
+
+    if sig:
+        nl = "\n"
+        ret = (
+            f'{ret}<div id="signature"><span class="sig_separator">{EMAIL_SIG_SEP.strip(nl)}</span>\n'  # noqa: E501
+            f"{sig}\n"
+            "</div>"
+        )
+
+    return f"{ret}\n  </body>\n</html>"
+
+
+def make_text_mail(text, sig=None):
+    return EMAIL_SIG_SEP.join((text, sig)) if sig else text
+
+
+def extract_signature(text, *, filefactory=FileFactory()):
+    parts = text.split(EMAIL_SIG_SEP, 1)
+    if len(parts) == 1:
+        return text, None, None
+
+    lines = parts[1].splitlines()
+    if lines[0].startswith(HTML_SIG_MARKER):
+        path = pathlib.Path(re.split(r" +", lines.pop(0), maxsplit=1)[1])
+        textsig = "\n".join(lines)
+
+        sig_input = filefactory(path.expanduser()).read()
+        soup = bs4.BeautifulSoup(sig_input, "html.parser")
+
+        style = str(soup.style.extract()) if soup.style else ""
+        for sig_selector in (
+            "#signature",
+            "#signatur",
+            "#emailsig",
+            ".signature",
+            ".signatur",
+            ".emailsig",
+            "body",
+            "div",
+        ):
+            sig = soup.select_one(sig_selector)
+            if sig:
+                break
+
+        if not sig:
+            return parts[0], textsig, style + sig_input
+
+        if sig.attrs.get("id") == "signature":
+            sig = "".join(str(c) for c in sig.children)
+
+        return parts[0], textsig, style + str(sig)
+
+    return parts[0], parts[1], None
+
+

 def convert_markdown_to_html(
 def convert_markdown_to_html(

-    origtext,
-    draftpath,
+    draft_f,

     *,
     related_to_html_only=False,
     *,
     related_to_html_only=False,

-    cssfile=None,
-    filewriter_fn=filewriter_fn,
+    css_f=None,
+    htmldump_f=None,
+    filefactory=FileFactory(),

     tempdir=None,
     extensions=None,
     extension_configs=None,
 ):
     # TODO extension_configs need to be handled differently
     extension_configs = extension_configs or {}
     tempdir=None,
     extensions=None,
     extension_configs=None,
 ):
     # TODO extension_configs need to be handled differently
     extension_configs = extension_configs or {}

-    extension_configs.setdefault("pymdownx.highlight", {})
-    extension_configs["pymdownx.highlight"]["css_class"] = _CODEHILITE_CLASS
+    extension_configs.setdefault("pymdownx.highlight", {})[
+        "css_class"
+    ] = _CODEHILITE_CLASS
+
+    extensions = extensions or []
+    extensions.append(QuoteToAdmonitionExtension())

 
 

-    origtext, htmltext, images = markdown_with_inline_image_support(
+    draft = draft_f.read()
+    origtext, textsig, htmlsig = extract_signature(
+        draft, filefactory=filefactory
+    )
+
+    (
+        origtext,
+        htmltext,
+        image_registry,
+        mdwn,
+    ) = markdown_with_inline_image_support(

         origtext, extensions=extensions, extension_configs=extension_configs
     )
 
         origtext, extensions=extensions, extension_configs=extension_configs
     )
 

-    filewriter_fn(draftpath, origtext, encoding="utf-8")
+    if htmlsig:
+        if not textsig:
+            # TODO: decide what to do if there is no plain-text version
+            raise NotImplementedError("HTML signature but no text alternative")
+
+        soup = bs4.BeautifulSoup(htmlsig, "html.parser")
+        for img in soup.find_all("img"):
+            uri = img.attrs["src"]
+            desc = img.attrs.get("title", img.attrs.get("alt"))
+            cid = image_registry.register(uri, desc)
+            img.attrs["src"] = f"cid:{cid}"
+
+        htmlsig = str(soup)
+
+    elif textsig:
+        (
+            textsig,
+            htmlsig,
+            image_registry,
+            mdwn,
+        ) = markdown_with_inline_image_support(
+            textsig,
+            extensions=extensions,
+            extension_configs=extension_configs,
+            image_registry=image_registry,
+            mdwn=mdwn,
+        )
+
+    origtext = make_text_mail(origtext, textsig)
+    draft_f.write(origtext)

     textpart = Part(
     textpart = Part(

-        "text", "plain", draftpath, "Plain-text version", orig=True
+        "text", "plain", draft_f.path, "Plain-text version", orig=True

     )
 
     )
 

-    htmltext = apply_styling(htmltext, cssfile)
+    htmltext = make_html_doc(htmltext, htmlsig)
+    htmltext = apply_styling(htmltext, css_f.read() if css_f else None)

 
 

-    htmlpath = draftpath.with_suffix(".html")
-    filewriter_fn(
-        htmlpath, htmltext, encoding="utf-8", errors="xmlcharrefreplace"
-    )
+    if draft_f.path:
+        htmlpath = draft_f.path.with_suffix(".html")
+    else:
+        htmlpath = pathlib.Path(
+            tempfile.mkstemp(suffix=".html", dir=tempdir)[1]
+        )
+    with filefactory(
+        htmlpath, "w", encoding="utf-8", errors="xmlcharrefreplace"
+    ) as out_f:
+        out_f.write(htmltext)

     htmlpart = Part("text", "html", htmlpath, "HTML version")
 
     htmlpart = Part("text", "html", htmlpath, "HTML version")
 

+    if htmldump_f:
+        htmldump_f.write(htmltext)
+

     imgparts = collect_inline_images(
     imgparts = collect_inline_images(

-        images, tempdir=tempdir, filewriter_fn=filewriter_fn
+        image_registry, tempdir=tempdir, filefactory=filefactory

     )
 
     if related_to_html_only:
     )
 
     if related_to_html_only:


@@ -482,7 +877,7 @@ class MuttCommands:
             self._cmd1.append(s)
 
     def push(self, s):
             self._cmd1.append(s)
 
     def push(self, s):

-        s = s.replace('"', '"')
+        s = s.replace('"', r"\"")

         s = f'push "{s}"'
         self.debugprint(s)
         self._push.insert(0, s)
         s = f'push "{s}"'
         self.debugprint(s)
         self._push.insert(0, s)


@@ -523,11 +918,11 @@ def do_setup(
 
 def do_massage(
     draft_f,
 
 def do_massage(
     draft_f,

-    draftpath,

     cmd_f,
     *,
     extensions=None,
     cmd_f,
     *,
     extensions=None,

-    cssfile=None,
+    css_f=None,
+    htmldump_f=None,

     converter=convert_markdown_to_html,
     related_to_html_only=True,
     only_build=False,
     converter=convert_markdown_to_html,
     related_to_html_only=True,
     only_build=False,


@@ -556,9 +951,9 @@ def do_massage(
 
     extensions = extensions.split(",") if extensions else []
     tree = converter(
 
     extensions = extensions.split(",") if extensions else []
     tree = converter(

-        draft_f.read(),
-        draftpath,
-        cssfile=cssfile,
+        draft_f,
+        css_f=css_f,
+        htmldump_f=htmldump_f,

         related_to_html_only=related_to_html_only,
         tempdir=tempdir,
         extensions=extensions,
         related_to_html_only=related_to_html_only,
         tempdir=tempdir,
         extensions=extensions,


@@ -625,7 +1020,7 @@ def do_massage(
                     # number of possible attachments. The performance
                     # difference of using a high number is negligible.
                     # Bubble up the new part
                     # number of possible attachments. The performance
                     # difference of using a high number is negligible.
                     # Bubble up the new part

-                    cmds.push(f"<move-up>")
+                    cmds.push("<move-up>")

 
                 # As we push the part to the right position in the list (i.e.
                 # the last of the subset of attachments this script added), we
 
                 # As we push the part to the right position in the list (i.e.
                 # the last of the subset of attachments this script added), we


@@ -634,7 +1029,7 @@ def do_massage(
                 # is decremented by the number of descendents so far
                 # encountered.
                 for i in range(1, state["pos"] - len(descendents)):
                 # is decremented by the number of descendents so far
                 # encountered.
                 for i in range(1, state["pos"] - len(descendents)):

-                    cmds.push(f"<move-down>")
+                    cmds.push("<move-down>")

 
         elif isinstance(item, Multipart):
             # This node has children, but we already visited them (see
 
         elif isinstance(item, Multipart):
             # This node has children, but we already visited them (see


@@ -714,15 +1109,18 @@ if __name__ == "__main__":
         )
 
     elif args.mode == "massage":
         )
 
     elif args.mode == "massage":

-        with open(args.MAILDRAFT, "r") as draft_f, open(
-            args.cmdpath, "w"
-        ) as cmd_f:
+        with (
+            File(args.MAILDRAFT, "r+") as draft_f,
+            File(args.cmdpath, "w") as cmd_f,
+            File(args.css_file, "r") as css_f,
+            File(args.dump_html, "w") as htmldump_f,
+        ):

             do_massage(
                 draft_f,
             do_massage(
                 draft_f,

-                args.MAILDRAFT,

                 cmd_f,
                 extensions=args.extensions,
                 cmd_f,
                 extensions=args.extensions,

-                cssfile=args.css_file,
+                css_f=css_f,
+                htmldump_f=htmldump_f,

                 related_to_html_only=args.related_to_html_only,
                 max_other_attachments=args.max_number_other_attachments,
                 only_build=args.only_build,
                 related_to_html_only=args.related_to_html_only,
                 max_other_attachments=args.max_number_other_attachments,
                 only_build=args.only_build,


@@ -736,20 +1134,28 @@ if __name__ == "__main__":
 
 try:
     import pytest
 
 try:
     import pytest

-    from io import StringIO

 
     class Tests:
         @pytest.fixture
         def const1(self):
 
     class Tests:
         @pytest.fixture
         def const1(self):

-            return "CONSTANT STRING 1"
+            return "Curvature Vest Usher Dividing+T#iceps Senior"

 
         @pytest.fixture
         def const2(self):
 
         @pytest.fixture
         def const2(self):

-            return "CONSTANT STRING 2"
+            return "Habitant Celestial 2litzy Resurf/ce Headpiece Harmonics"
+
+        @pytest.fixture
+        def fakepath(self):
+            return pathlib.Path("/does/not/exist")
+
+        @pytest.fixture
+        def fakepath2(self):
+            return pathlib.Path("/does/not/exist/either")

 
         # NOTE: tests using the capsys fixture must specify sys.stdout to the
         # functions they call, else old stdout is used and not captured
 
 
         # NOTE: tests using the capsys fixture must specify sys.stdout to the
         # functions they call, else old stdout is used and not captured
 

+        @pytest.mark.muttctrl

         def test_MuttCommands_cmd(self, const1, const2, capsys):
             "Assert order of commands"
             cmds = MuttCommands(out_f=sys.stdout)
         def test_MuttCommands_cmd(self, const1, const2, capsys):
             "Assert order of commands"
             cmds = MuttCommands(out_f=sys.stdout)


@@ -759,6 +1165,7 @@ try:
             captured = capsys.readouterr()
             assert captured.out == "\n".join((const1, const2, ""))
 
             captured = capsys.readouterr()
             assert captured.out == "\n".join((const1, const2, ""))
 

+        @pytest.mark.muttctrl

         def test_MuttCommands_push(self, const1, const2, capsys):
             "Assert reverse order of pushes"
             cmds = MuttCommands(out_f=sys.stdout)
         def test_MuttCommands_push(self, const1, const2, capsys):
             "Assert reverse order of pushes"
             cmds = MuttCommands(out_f=sys.stdout)


@@ -771,6 +1178,15 @@ try:
                 == ('"\npush "'.join(("", const2, const1, "")))[2:-6]
             )
 
                 == ('"\npush "'.join(("", const2, const1, "")))[2:-6]
             )
 

+        @pytest.mark.muttctrl
+        def test_MuttCommands_push_escape(self, const1, const2, capsys):
+            cmds = MuttCommands(out_f=sys.stdout)
+            cmds.push(f'"{const1}"')
+            cmds.flush()
+            captured = capsys.readouterr()
+            assert f'"\\"{const1}\\""' in captured.out
+
+        @pytest.mark.muttctrl

         def test_MuttCommands_cmd_push_mixed(self, const1, const2, capsys):
             "Assert reverse order of pushes"
             cmds = MuttCommands(out_f=sys.stdout)
         def test_MuttCommands_cmd_push_mixed(self, const1, const2, capsys):
             "Assert reverse order of pushes"
             cmds = MuttCommands(out_f=sys.stdout)


@@ -849,6 +1265,54 @@ try:
                 desc="Alternative",
             )
 
                 desc="Alternative",
             )
 

+        @pytest.fixture
+        def mime_tree_nested(self):
+            return Multipart(
+                "relative",
+                children=[
+                    Multipart(
+                        "alternative",
+                        children=[
+                            Part(
+                                "text",
+                                "plain",
+                                "part.txt",
+                                desc="Plain",
+                                orig=True,
+                            ),
+                            Multipart(
+                                "alternative",
+                                children=[
+                                    Part(
+                                        "text",
+                                        "plain",
+                                        "part.txt",
+                                        desc="Nested plain",
+                                    ),
+                                    Part(
+                                        "text",
+                                        "html",
+                                        "part.html",
+                                        desc="Nested HTML",
+                                    ),
+                                ],
+                                desc="Nested alternative",
+                            ),
+                        ],
+                        desc="Alternative",
+                    ),
+                    Part(
+                        "text",
+                        "png",
+                        "logo.png",
+                        cid="logo.png",
+                        desc="Logo",
+                    ),
+                ],
+                desc="Related",
+            )
+
+        @pytest.mark.treewalk

         def test_MIMETreeDFWalker_depth_first_walk(
             self, mime_tree_related_to_alternative
         ):
         def test_MIMETreeDFWalker_depth_first_walk(
             self, mime_tree_related_to_alternative
         ):


@@ -879,6 +1343,7 @@ try:
             assert items[4][1] == 0
             assert items[4][2] == 4
 
             assert items[4][1] == 0
             assert items[4][2] == 4
 

+        @pytest.mark.treewalk

         def test_MIMETreeDFWalker_list_to_mixed(self, const1):
             mimetree = MIMETreeDFWalker()
             items = []
         def test_MIMETreeDFWalker_list_to_mixed(self, const1):
             mimetree = MIMETreeDFWalker()
             items = []


@@ -892,6 +1357,7 @@ try:
             mimetree.walk([p, p], visitor_fn=visitor_fn)
             assert items[-1].subtype == "mixed"
 
             mimetree.walk([p, p], visitor_fn=visitor_fn)
             assert items[-1].subtype == "mixed"
 

+        @pytest.mark.treewalk

         def test_MIMETreeDFWalker_visitor_in_constructor(
             self, mime_tree_related_to_alternative
         ):
         def test_MIMETreeDFWalker_visitor_in_constructor(
             self, mime_tree_related_to_alternative
         ):


@@ -908,26 +1374,19 @@ try:
         def string_io(self, const1, text=None):
             return StringIO(text or const1)
 
         def string_io(self, const1, text=None):
             return StringIO(text or const1)
 

-        def test_do_massage_basic(self, const1, string_io, capsys):
-            def converter(
-                drafttext,
-                draftpath,
-                cssfile,
-                related_to_html_only,
-                extensions,
-                tempdir,
-            ):
-                return Part("text", "plain", draftpath, orig=True)
+        @pytest.mark.massage
+        def test_do_massage_basic(self):
+            def converter(draft_f, **kwargs):
+                return Part("text", "plain", draft_f.path, orig=True)

 
 

-            do_massage(
-                draft_f=string_io,
-                draftpath=const1,
-                cmd_f=sys.stdout,
-                converter=converter,
-            )
+            with File() as draft_f, File() as cmd_f:
+                do_massage(
+                    draft_f=draft_f,
+                    cmd_f=cmd_f,
+                    converter=converter,
+                )
+                lines = cmd_f.read().splitlines()

 
 

-            captured = capsys.readouterr()
-            lines = captured.out.splitlines()

             assert '="$my_editor"' in lines.pop(0)
             assert '="$my_edit_headers"' in lines.pop(0)
             assert "unset my_editor" == lines.pop(0)
             assert '="$my_editor"' in lines.pop(0)
             assert '="$my_edit_headers"' in lines.pop(0)
             assert "unset my_editor" == lines.pop(0)


@@ -938,30 +1397,22 @@ try:
             assert "source 'rm -f " in lines.pop(0)
             assert "unset my_mdwn_postprocess_cmd_file" == lines.pop(0)
 
             assert "source 'rm -f " in lines.pop(0)
             assert "unset my_mdwn_postprocess_cmd_file" == lines.pop(0)
 

-        def test_do_massage_fulltree(
-            self, string_io, const1, mime_tree_related_to_alternative, capsys
-        ):
-            def converter(
-                drafttext,
-                draftpath,
-                cssfile,
-                related_to_html_only,
-                extensions,
-                tempdir,
-            ):
+        @pytest.mark.massage
+        def test_do_massage_fulltree(self, mime_tree_related_to_alternative):
+            def converter(draft_f, **kwargs):

                 return mime_tree_related_to_alternative
 
             max_attachments = 5
                 return mime_tree_related_to_alternative
 
             max_attachments = 5

-            do_massage(
-                draft_f=string_io,
-                draftpath=const1,
-                cmd_f=sys.stdout,
-                max_other_attachments=max_attachments,
-                converter=converter,
-            )

 
 

-            captured = capsys.readouterr()
-            lines = captured.out.splitlines()[4:-2]
+            with File() as draft_f, File() as cmd_f:
+                do_massage(
+                    draft_f=draft_f,
+                    cmd_f=cmd_f,
+                    max_other_attachments=max_attachments,
+                    converter=converter,
+                )
+                lines = cmd_f.read().splitlines()[4:-2]
+

             assert "first-entry" in lines.pop()
             assert "update-encoding" in lines.pop()
             assert "Plain" in lines.pop()
             assert "first-entry" in lines.pop()
             assert "update-encoding" in lines.pop()
             assert "Plain" in lines.pop()


@@ -989,60 +1440,117 @@ try:
             assert "send-message" in lines.pop()
             assert len(lines) == 0
 
             assert "send-message" in lines.pop()
             assert len(lines) == 0
 

-        @pytest.fixture
-        def fake_filewriter(self):
-            class FileWriter:
-                def __init__(self):
-                    self._writes = []
+        @pytest.mark.massage
+        def test_mime_tree_relative_within_alternative(
+            self, mime_tree_related_to_html
+        ):
+            def converter(draft_f, **kwargs):
+                return mime_tree_related_to_html

 
 

-                def __call__(self, path, content, mode="w", **kwargs):
-                    self._writes.append((path, content))
+            with File() as draft_f, File() as cmd_f:
+                do_massage(
+                    draft_f=draft_f,
+                    cmd_f=cmd_f,
+                    converter=converter,
+                )
+                lines = cmd_f.read().splitlines()[4:-2]

 
 

-                def pop(self, index=-1):
-                    return self._writes.pop(index)
+            assert "first-entry" in lines.pop()
+            assert "update-encoding" in lines.pop()
+            assert "Plain" in lines.pop()
+            assert "part.html" in lines.pop()
+            assert "toggle-unlink" in lines.pop()
+            assert "move-up" in lines.pop()
+            while True:
+                top = lines.pop()
+                if "move-up" not in top:
+                    break
+            assert "move-down" in top
+            assert "HTML" in lines.pop()
+            assert "logo.png" in lines.pop()
+            assert "toggle-unlink" in lines.pop()
+            assert "content-id" in lines.pop()
+            assert "move-up" in lines.pop()
+            while True:
+                top = lines.pop()
+                if "move-up" not in top:
+                    break
+            assert "move-down" in top
+            assert "move-down" in lines.pop()
+            assert "Logo" in lines.pop()
+            assert "jump>2" in lines.pop()
+            assert "jump>3" in lines.pop()
+            assert "group-related" in lines.pop()
+            assert "Related" in lines.pop()
+            assert "jump>1" in lines.pop()
+            assert "jump>2" in lines.pop()
+            assert "group-alternative" in lines.pop()
+            assert "Alternative" in lines.pop()
+            assert "send-message" in lines.pop()
+            assert len(lines) == 0

 
 

-            return FileWriter()
+        @pytest.mark.massage
+        def test_mime_tree_nested_trees_does_not_break_positioning(
+            self, mime_tree_nested
+        ):
+            def converter(draft_f, **kwargs):
+                return mime_tree_nested
+
+            with File() as draft_f, File() as cmd_f:
+                do_massage(
+                    draft_f=draft_f,
+                    cmd_f=cmd_f,
+                    converter=converter,
+                )
+                lines = cmd_f.read().splitlines()

 
 

-        @pytest.fixture
-        def markdown_non_converter(self, const1, const2):
-            return lambda s, text: f"{const1}{text}{const2}"
+            while "logo.png" not in lines.pop():
+                pass
+            lines.pop()
+            assert "content-id" in lines.pop()
+            assert "move-up" in lines.pop()
+            while True:
+                top = lines.pop()
+                if "move-up" not in top:
+                    break
+            assert "move-down" in top
+            # Due to the nested trees, the number of descendents of the sibling
+            # actually needs to be considered, not just the nieces. So to move
+            # from position 1 to position 6, it only needs one <move-down>
+            # because that jumps over the entire sibling tree. Thus what
+            # follows next must not be another <move-down>
+            assert "Logo" in lines.pop()

 
 

-        def test_converter_tree_basic(self, const1, const2, fake_filewriter):
-            path = pathlib.Path(const2)
+        @pytest.mark.converter
+        def test_converter_tree_basic(self, fakepath, const1, fakefilefactory):
+            draft_f = fakefilefactory(fakepath, content=const1)

             tree = convert_markdown_to_html(
             tree = convert_markdown_to_html(

-                const1, path, filewriter_fn=fake_filewriter
+                draft_f, filefactory=fakefilefactory

             )
 
             assert tree.subtype == "alternative"
             assert len(tree.children) == 2
             assert tree.children[0].subtype == "plain"
             )
 
             assert tree.subtype == "alternative"
             assert len(tree.children) == 2
             assert tree.children[0].subtype == "plain"

-            assert tree.children[0].path == path
+            assert tree.children[0].path == draft_f.path

             assert tree.children[0].orig
             assert tree.children[1].subtype == "html"
             assert tree.children[0].orig
             assert tree.children[1].subtype == "html"

-            assert tree.children[1].path == path.with_suffix(".html")
+            assert tree.children[1].path == fakepath.with_suffix(".html")

 
 

+        @pytest.mark.converter

         def test_converter_writes(
         def test_converter_writes(

-            self,
-            const1,
-            const2,
-            fake_filewriter,
-            monkeypatch,
-            markdown_non_converter,
+            self, fakepath, fakefilefactory, const1, monkeypatch

         ):
         ):

-            path = pathlib.Path(const2)
+            draft_f = fakefilefactory(fakepath, content=const1)
+            convert_markdown_to_html(draft_f, filefactory=fakefilefactory)

 
 

-            with monkeypatch.context() as m:
-                m.setattr(markdown.Markdown, "convert", markdown_non_converter)
-                convert_markdown_to_html(
-                    const1, path, filewriter_fn=fake_filewriter
-                )
-
-            assert (path, const1) == fake_filewriter.pop(0)
-            assert (
-                path.with_suffix(".html"),
-                markdown_non_converter(None, const1),
-            ) == fake_filewriter.pop(0)
+            html = fakefilefactory.pop()
+            assert fakepath.with_suffix(".html") == html[0]
+            assert const1 in html[1].read()
+            text = fakefilefactory.pop()
+            assert fakepath == text[0]
+            assert const1 == text[1].read()

 
 

+        @pytest.mark.imgproc

         def test_markdown_inline_image_processor(self):
             imgpath1 = "file:/path/to/image.png"
             imgpath2 = "file:///path/to/image.png?url=params"
         def test_markdown_inline_image_processor(self):
             imgpath1 = "file:/path/to/image.png"
             imgpath2 = "file:///path/to/image.png?url=params"


@@ -1051,7 +1559,7 @@ try:
                        ![image inlined
                          with newline]({imgpath2})
                        ![image local path]({imgpath3})"""
                        ![image inlined
                          with newline]({imgpath2})
                        ![image local path]({imgpath3})"""

-            text, html, images = markdown_with_inline_image_support(text)
+            text, html, images, mdwn = markdown_with_inline_image_support(text)

 
             # local paths have been normalised to URLs:
             imgpath3 = f"file://{imgpath3}"
 
             # local paths have been normalised to URLs:
             imgpath3 = f"file://{imgpath3}"


@@ -1066,44 +1574,59 @@ try:
             assert images[imgpath1].cid != images[imgpath3].cid
             assert images[imgpath2].cid != images[imgpath3].cid
 
             assert images[imgpath1].cid != images[imgpath3].cid
             assert images[imgpath2].cid != images[imgpath3].cid
 

+        @pytest.mark.imgproc

         def test_markdown_inline_image_processor_title_to_desc(self, const1):
             imgpath = "file:///path/to/image.png"
             text = f'![inline local image]({imgpath} "{const1}")'
         def test_markdown_inline_image_processor_title_to_desc(self, const1):
             imgpath = "file:///path/to/image.png"
             text = f'![inline local image]({imgpath} "{const1}")'

-            text, html, images = markdown_with_inline_image_support(text)
+            text, html, images, mdwn = markdown_with_inline_image_support(text)

             assert images[imgpath].desc == const1
 
             assert images[imgpath].desc == const1
 

+        @pytest.mark.imgproc

         def test_markdown_inline_image_processor_alt_to_desc(self, const1):
             imgpath = "file:///path/to/image.png"
             text = f"![{const1}]({imgpath})"
         def test_markdown_inline_image_processor_alt_to_desc(self, const1):
             imgpath = "file:///path/to/image.png"
             text = f"![{const1}]({imgpath})"

-            text, html, images = markdown_with_inline_image_support(text)
+            text, html, images, mdwn = markdown_with_inline_image_support(text)

             assert images[imgpath].desc == const1
 
             assert images[imgpath].desc == const1
 

+        @pytest.mark.imgproc

         def test_markdown_inline_image_processor_title_over_alt_desc(
             self, const1, const2
         ):
             imgpath = "file:///path/to/image.png"
             text = f'![{const1}]({imgpath} "{const2}")'
         def test_markdown_inline_image_processor_title_over_alt_desc(
             self, const1, const2
         ):
             imgpath = "file:///path/to/image.png"
             text = f'![{const1}]({imgpath} "{const2}")'

-            text, html, images = markdown_with_inline_image_support(text)
+            text, html, images, mdwn = markdown_with_inline_image_support(text)

             assert images[imgpath].desc == const2
 
             assert images[imgpath].desc == const2
 

+        @pytest.mark.imgproc

         def test_markdown_inline_image_not_external(self):
             imgpath = "https://path/to/image.png"
             text = f"![inline image]({imgpath})"
         def test_markdown_inline_image_not_external(self):
             imgpath = "https://path/to/image.png"
             text = f"![inline image]({imgpath})"

-            text, html, images = markdown_with_inline_image_support(text)
+            text, html, images, mdwn = markdown_with_inline_image_support(text)

 
             assert 'src="cid:' not in html
             assert "](cid:" not in text
             assert len(images) == 0
 
 
             assert 'src="cid:' not in html
             assert "](cid:" not in text
             assert len(images) == 0
 

+        @pytest.mark.imgproc

         def test_markdown_inline_image_local_file(self):
             imgpath = "/path/to/image.png"
             text = f"![inline image]({imgpath})"
         def test_markdown_inline_image_local_file(self):
             imgpath = "/path/to/image.png"
             text = f"![inline image]({imgpath})"

-            text, html, images = markdown_with_inline_image_support(text)
+            text, html, images, mdwn = markdown_with_inline_image_support(text)

 
             for k, v in images.items():
                 assert k == f"file://{imgpath}"
                 break
 
 
             for k, v in images.items():
                 assert k == f"file://{imgpath}"
                 break
 

+        @pytest.mark.imgproc
+        def test_markdown_inline_image_expanduser(self):
+            imgpath = pathlib.Path("~/image.png")
+            text = f"![inline image]({imgpath})"
+            text, html, images, mdwn = markdown_with_inline_image_support(text)
+
+            for k, v in images.items():
+                assert k == f"file://{imgpath.expanduser()}"
+                break
+

         @pytest.fixture
         def test_png(self):
             return (
         @pytest.fixture
         def test_png(self):
             return (


@@ -1111,93 +1634,151 @@ try:
                 "AAAABCAAAAAA6fptVAAAACklEQVQI12P4DwABAQEAG7buVgAA"
             )
 
                 "AAAABCAAAAAA6fptVAAAACklEQVQI12P4DwABAQEAG7buVgAA"
             )
 

+        @pytest.mark.imgproc

         def test_markdown_inline_image_processor_base64(self, test_png):
             text = f"![1px white inlined]({test_png})"
         def test_markdown_inline_image_processor_base64(self, test_png):
             text = f"![1px white inlined]({test_png})"

-            text, html, images = markdown_with_inline_image_support(text)
+            text, html, images, mdwn = markdown_with_inline_image_support(text)

 
             assert 'src="cid:' in html
             assert "](cid:" in text
             assert len(images) == 1
             assert test_png in images
 
 
             assert 'src="cid:' in html
             assert "](cid:" in text
             assert len(images) == 1
             assert test_png in images
 

+        @pytest.mark.converter

         def test_converter_tree_inline_image_base64(
         def test_converter_tree_inline_image_base64(

-            self, test_png, const1, fake_filewriter
+            self, test_png, fakefilefactory

         ):
             text = f"![inline base64 image]({test_png})"
         ):
             text = f"![inline base64 image]({test_png})"

-            path = pathlib.Path(const1)
-            tree = convert_markdown_to_html(
-                text,
-                path,
-                filewriter_fn=fake_filewriter,
-                related_to_html_only=False,
-            )
+            with fakefilefactory(content=text) as draft_f:
+                tree = convert_markdown_to_html(
+                    draft_f,
+                    filefactory=fakefilefactory,
+                    related_to_html_only=False,
+                )

             assert tree.subtype == "relative"
             assert tree.children[0].subtype == "alternative"
             assert tree.children[1].subtype == "png"
             assert tree.subtype == "relative"
             assert tree.children[0].subtype == "alternative"
             assert tree.children[1].subtype == "png"

-            written = fake_filewriter.pop()
+            written = fakefilefactory.pop()

             assert tree.children[1].path == written[0]
             assert tree.children[1].path == written[0]

-            assert written[1] == request.urlopen(test_png).read()
+            assert b"PNG" in written[1].read()

 
 

+        @pytest.mark.converter

         def test_converter_tree_inline_image_base64_related_to_html(
         def test_converter_tree_inline_image_base64_related_to_html(

-            self, test_png, const1, fake_filewriter
+            self, test_png, fakefilefactory

         ):
             text = f"![inline base64 image]({test_png})"
         ):
             text = f"![inline base64 image]({test_png})"

-            path = pathlib.Path(const1)
-            tree = convert_markdown_to_html(
-                text,
-                path,
-                filewriter_fn=fake_filewriter,
-                related_to_html_only=True,
-            )
+            with fakefilefactory(content=text) as draft_f:
+                tree = convert_markdown_to_html(
+                    draft_f,
+                    filefactory=fakefilefactory,
+                    related_to_html_only=True,
+                )

             assert tree.subtype == "alternative"
             assert tree.children[1].subtype == "relative"
             assert tree.children[1].children[1].subtype == "png"
             assert tree.subtype == "alternative"
             assert tree.children[1].subtype == "relative"
             assert tree.children[1].children[1].subtype == "png"

-            written = fake_filewriter.pop()
+            written = fakefilefactory.pop()

             assert tree.children[1].children[1].path == written[0]
             assert tree.children[1].children[1].path == written[0]

-            assert written[1] == request.urlopen(test_png).read()
+            assert b"PNG" in written[1].read()

 
 

+        @pytest.mark.converter

         def test_converter_tree_inline_image_cid(
         def test_converter_tree_inline_image_cid(

-            self, const1, fake_filewriter
+            self, const1, fakefilefactory

         ):
             text = f"![inline base64 image](cid:{const1})"
         ):
             text = f"![inline base64 image](cid:{const1})"

-            path = pathlib.Path(const1)
-            tree = convert_markdown_to_html(
-                text,
-                path,
-                filewriter_fn=fake_filewriter,
-                related_to_html_only=False,
-            )
+            with fakefilefactory(content=text) as draft_f:
+                tree = convert_markdown_to_html(
+                    draft_f,
+                    filefactory=fakefilefactory,
+                    related_to_html_only=False,
+                )

             assert len(tree.children) == 2
             assert tree.children[0].cid != const1
             assert tree.children[0].type != "image"
             assert tree.children[1].cid != const1
             assert tree.children[1].type != "image"
 
             assert len(tree.children) == 2
             assert tree.children[0].cid != const1
             assert tree.children[0].type != "image"
             assert tree.children[1].cid != const1
             assert tree.children[1].type != "image"
 

+        @pytest.fixture
+        def fakefilefactory(self):
+            return FakeFileFactory()
+
+        @pytest.mark.imgcoll

         def test_inline_image_collection(
         def test_inline_image_collection(

-            self, test_png, const1, const2, fake_filewriter
+            self, test_png, const1, const2, fakefilefactory

         ):
             test_images = {test_png: InlineImageInfo(cid=const1, desc=const2)}
             relparts = collect_inline_images(
         ):
             test_images = {test_png: InlineImageInfo(cid=const1, desc=const2)}
             relparts = collect_inline_images(

-                test_images, filewriter_fn=fake_filewriter
+                test_images, filefactory=fakefilefactory

             )
 
             )
 

-            written = fake_filewriter.pop()
-            assert b"PNG" in written[1]
+            written = fakefilefactory.pop()
+            assert b"PNG" in written[1].read()

 
             assert relparts[0].subtype == "png"
             assert relparts[0].path == written[0]
             assert relparts[0].cid == const1
 
             assert relparts[0].subtype == "png"
             assert relparts[0].path == written[0]
             assert relparts[0].cid == const1

-            assert relparts[0].desc.endswith(const2)
+            assert const2 in relparts[0].desc

 
 

-        def test_apply_stylesheet(self):
-            if _PYNLINER:
+        if _PYNLINER:
+
+            @pytest.mark.styling
+            def test_apply_stylesheet(self):

                 html = "<p>Hello, world!</p>"
                 css = "p { color:red }"
                 out = apply_styling(html, css)
                 assert 'p style="color' in out
 
                 html = "<p>Hello, world!</p>"
                 css = "p { color:red }"
                 out = apply_styling(html, css)
                 assert 'p style="color' in out
 

-        def test_apply_stylesheet_pygments(self):
-            if _PYGMENTS_CSS:
+            @pytest.mark.styling
+            def test_apply_no_stylesheet(self, const1):
+                out = apply_styling(const1, None)
+
+            @pytest.mark.massage
+            @pytest.mark.styling
+            def test_massage_styling_to_converter(self):
+                css = "p { color:red }"
+                css_f = File(content=css)
+                css_applied = []
+
+                def converter(draft_f, css_f, **kwargs):
+                    css = css_f.read()
+                    css_applied.append(css)
+                    return Part("text", "plain", draft_f.path, orig=True)
+
+                do_massage(
+                    draft_f=File(),
+                    cmd_f=File(),
+                    css_f=css_f,
+                    converter=converter,
+                )
+                assert css_applied[0] == css
+
+            @pytest.mark.converter
+            @pytest.mark.styling
+            def test_converter_apply_styles(
+                self, const1, monkeypatch, fakepath, fakefilefactory
+            ):
+                css = "p { color:red }"
+                with (
+                    monkeypatch.context() as m,
+                    fakefilefactory(fakepath, content=const1) as draft_f,
+                    fakefilefactory(content=css) as css_f,
+                ):
+                    m.setattr(
+                        markdown.Markdown,
+                        "convert",
+                        lambda s, t: f"<p>{t}</p>",
+                    )
+                    convert_markdown_to_html(
+                        draft_f, css_f=css_f, filefactory=fakefilefactory
+                    )
+                assert re.search(
+                    r"color:.*red",
+                    fakefilefactory[fakepath.with_suffix(".html")].read(),
+                )
+
+        if _PYGMENTS_CSS:
+
+            @pytest.mark.styling
+            def test_apply_stylesheet_pygments(self):

                 html = (
                     f'<div class="{_CODEHILITE_CLASS}">'
                     "<pre>def foo():\n    return</pre></div>"
                 html = (
                     f'<div class="{_CODEHILITE_CLASS}">'
                     "<pre>def foo():\n    return</pre></div>"


@@ -1205,143 +1786,379 @@ try:
                 out = apply_styling(html, _PYGMENTS_CSS)
                 assert f'{_CODEHILITE_CLASS}" style="' in out
 
                 out = apply_styling(html, _PYGMENTS_CSS)
                 assert f'{_CODEHILITE_CLASS}" style="' in out
 

-        def test_mime_tree_relative_within_alternative(
-            self, string_io, const1, capsys, mime_tree_related_to_html
+        @pytest.mark.sig
+        def test_signature_extraction_no_signature(self, const1):
+            assert (const1, None, None) == extract_signature(const1)
+
+        @pytest.mark.sig
+        def test_signature_extraction_just_text(self, const1, const2):
+            origtext, textsig, htmlsig = extract_signature(
+                f"{const1}{EMAIL_SIG_SEP}{const2}"
+            )
+            assert origtext == const1
+            assert textsig == const2
+            assert htmlsig is None
+
+        @pytest.mark.sig
+        def test_signature_extraction_html(
+            self, fakepath, fakefilefactory, const1, const2

         ):
         ):

-            def converter(
-                drafttext,
-                draftpath,
-                cssfile,
-                related_to_html_only,
-                extensions,
-                tempdir,
+            sigconst = "HTML signature from {path} but as a string"
+            sig = f'<div id="signature">{sigconst.format(path=fakepath)}</div>'
+
+            sig_f = fakefilefactory(fakepath, content=sig)
+
+            origtext, textsig, htmlsig = extract_signature(
+                f"{const1}{EMAIL_SIG_SEP}{HTML_SIG_MARKER} {fakepath}\n{const2}",
+                filefactory=fakefilefactory,
+            )
+            assert origtext == const1
+            assert textsig == const2
+            assert htmlsig == sigconst.format(path=fakepath)
+
+        @pytest.mark.sig
+        def test_signature_extraction_file_not_found(self, const1):
+            path = pathlib.Path("/does/not/exist")
+            with pytest.raises(FileNotFoundError):
+                origtext, textsig, htmlsig = extract_signature(
+                    f"{const1}{EMAIL_SIG_SEP}{HTML_SIG_MARKER}{path}\n{const1}"
+                )
+
+        @pytest.mark.imgproc
+        def test_image_registry(self, const1):
+            reg = ImageRegistry()
+            cid = reg.register(const1)
+            assert "@" in cid
+            assert not cid.startswith("<")
+            assert not cid.endswith(">")
+            assert const1 in reg
+
+        @pytest.mark.imgproc
+        def test_image_registry_file_uri(self, const1):
+            reg = ImageRegistry()
+            reg.register("/some/path")
+            for path in reg:
+                assert path.startswith("file://")
+                break
+
+        @pytest.mark.converter
+        @pytest.mark.sig
+        def test_converter_signature_handling(
+            self, fakepath, fakefilefactory, monkeypatch
+        ):
+            mailparts = (
+                "This is the mail body\n",
+                f"{EMAIL_SIG_SEP}",
+                "This is a plain-text signature only",
+            )
+
+            with (
+                fakefilefactory(
+                    fakepath, content="".join(mailparts)
+                ) as draft_f,
+                monkeypatch.context() as m,

             ):
             ):

-                return mime_tree_related_to_html
+                m.setattr(markdown.Markdown, "convert", lambda s, t: t)
+                convert_markdown_to_html(draft_f, filefactory=fakefilefactory)

 
 

-            do_massage(
-                draft_f=string_io,
-                draftpath=const1,
-                cmd_f=sys.stdout,
-                converter=converter,
+            soup = bs4.BeautifulSoup(
+                fakefilefactory[fakepath.with_suffix(".html")].read(),
+                "html.parser",

             )
             )

+            body = soup.body.contents

 
 

-            captured = capsys.readouterr()
-            lines = captured.out.splitlines()[4:-2]
-            assert "first-entry" in lines.pop()
-            assert "update-encoding" in lines.pop()
-            assert "Plain" in lines.pop()
-            assert "part.html" in lines.pop()
-            assert "toggle-unlink" in lines.pop()
-            assert "move-up" in lines.pop()
-            while True:
-                top = lines.pop()
-                if "move-up" not in top:
-                    break
-            assert "move-down" in top
-            assert "HTML" in lines.pop()
-            assert "logo.png" in lines.pop()
-            assert "toggle-unlink" in lines.pop()
-            assert "content-id" in lines.pop()
-            assert "move-up" in lines.pop()
-            while True:
-                top = lines.pop()
-                if "move-up" not in top:
-                    break
-            assert "move-down" in top
-            assert "move-down" in lines.pop()
-            assert "Logo" in lines.pop()
-            assert "jump>2" in lines.pop()
-            assert "jump>3" in lines.pop()
-            assert "group-related" in lines.pop()
-            assert "Related" in lines.pop()
-            assert "jump>1" in lines.pop()
-            assert "jump>2" in lines.pop()
-            assert "group-alternative" in lines.pop()
-            assert "Alternative" in lines.pop()
-            assert "send-message" in lines.pop()
-            assert len(lines) == 0
+            assert mailparts[0] in body.pop(0)

 
 

-        def test_mime_tree_nested_trees_does_not_break_positioning(
-            self, string_io, const1, capsys
+            sig = soup.select_one("#signature")
+            assert sig == body.pop(0)
+
+            sep = sig.select_one("span.sig_separator")
+            assert sep == sig.contents[0]
+            assert f"\n{sep.text}\n" == EMAIL_SIG_SEP
+
+            assert mailparts[2] in sig.contents[1]
+
+        @pytest.mark.converter
+        @pytest.mark.sig
+        def test_converter_signature_handling_htmlsig(
+            self, fakepath, fakepath2, fakefilefactory, monkeypatch

         ):
         ):

-            def converter(
-                drafttext,
-                draftpath,
-                cssfile,
-                related_to_html_only,
-                extensions,
-                tempdir,
+            mailparts = (
+                "This is the mail body",
+                f"{EMAIL_SIG_SEP}",
+                f"{HTML_SIG_MARKER}{fakepath2}\n",
+                "This is the plain-text version",
+            )
+            htmlsig = "HTML Signature from {path} but as a string"
+            html = (
+                f'<div id="signature"><p>{htmlsig.format(path=fakepath2)}</p></div>'
+            )
+
+            sig_f = fakefilefactory(fakepath2, content=html)
+
+            def mdwn_fn(t):
+                return t.upper()
+
+            with (
+                fakefilefactory(
+                    fakepath, content="".join(mailparts)
+                ) as draft_f,
+                monkeypatch.context() as m,

             ):
             ):

-                return Multipart(
-                    "relative",
-                    children=[
-                        Multipart(
-                            "alternative",
-                            children=[
-                                Part(
-                                    "text",
-                                    "plain",
-                                    "part.txt",
-                                    desc="Plain",
-                                    orig=True,
-                                ),
-                                Multipart(
-                                    "alternative",
-                                    children=[
-                                        Part(
-                                            "text",
-                                            "plain",
-                                            "part.txt",
-                                            desc="Nested plain",
-                                        ),
-                                        Part(
-                                            "text",
-                                            "html",
-                                            "part.html",
-                                            desc="Nested HTML",
-                                        ),
-                                    ],
-                                    desc="Nested alternative",
-                                ),
-                            ],
-                            desc="Alternative",
-                        ),
-                        Part(
-                            "text",
-                            "png",
-                            "logo.png",
-                            cid="logo.png",
-                            desc="Logo",
-                        ),
-                    ],
-                    desc="Related",
+                m.setattr(
+                    markdown.Markdown, "convert", lambda s, t: mdwn_fn(t)

                 )
                 )

+                convert_markdown_to_html(draft_f, filefactory=fakefilefactory)

 
 

-            do_massage(
-                draft_f=string_io,
-                draftpath=const1,
-                cmd_f=sys.stdout,
-                converter=converter,
+            soup = bs4.BeautifulSoup(
+                fakefilefactory[fakepath.with_suffix(".html")].read(),
+                "html.parser",

             )
             )

+            sig = soup.select_one("#signature")
+            sig.span.extract()

 
 

-            captured = capsys.readouterr()
-            lines = captured.out.splitlines()
-            while not "logo.png" in lines.pop():
-                pass
-            lines.pop()
-            assert "content-id" in lines.pop()
-            assert "move-up" in lines.pop()
-            while True:
-                top = lines.pop()
-                if "move-up" not in top:
-                    break
-            assert "move-down" in top
-            # Due to the nested trees, the number of descendents of the sibling
-            # actually needs to be considered, not just the nieces. So to move
-            # from position 1 to position 6, it only needs one <move-down>
-            # because that jumps over the entire sibling tree. Thus what
-            # follows next must not be another <move-down>
-            assert "Logo" in lines.pop()
+            assert HTML_SIG_MARKER not in sig.text
+            assert htmlsig.format(path=fakepath2) == sig.text.strip()
+
+            plaintext = fakefilefactory[fakepath].read()
+            assert plaintext.endswith(EMAIL_SIG_SEP + mailparts[-1])
+
+        @pytest.mark.converter
+        @pytest.mark.sig
+        def test_converter_signature_handling_htmlsig_with_image(
+            self, fakepath, fakepath2, fakefilefactory, monkeypatch, test_png
+        ):
+            mailparts = (
+                "This is the mail body",
+                f"{EMAIL_SIG_SEP}",
+                f"{HTML_SIG_MARKER}{fakepath2}\n",
+                "This is the plain-text version",
+            )
+            htmlsig = (
+                "HTML Signature from {path} with image\n"
+                f'<img src="{test_png}">\n'
+            )
+            html = (
+                f'<div id="signature">{htmlsig.format(path=fakepath2)}</div>'
+            )
+
+            sig_f = fakefilefactory(fakepath2, content=html)
+
+            def mdwn_fn(t):
+                return t.upper()
+
+            with (
+                fakefilefactory(
+                    fakepath, content="".join(mailparts)
+                ) as draft_f,
+                monkeypatch.context() as m,
+            ):
+                m.setattr(
+                    markdown.Markdown, "convert", lambda s, t: mdwn_fn(t)
+                )
+                convert_markdown_to_html(draft_f, filefactory=fakefilefactory)
+
+            assert fakefilefactory.pop()[0].suffix == ".png"
+
+            soup = bs4.BeautifulSoup(
+                fakefilefactory[fakepath.with_suffix(".html")].read(),
+                "html.parser",
+            )
+            assert soup.img.attrs["src"].startswith("cid:")
+
+        @pytest.mark.converter
+        @pytest.mark.sig
+        def test_converter_signature_handling_textsig_with_image(
+            self, fakepath, fakefilefactory, test_png
+        ):
+            mailparts = (
+                "This is the mail body",
+                f"{EMAIL_SIG_SEP}",
+                "This is the plain-text version with image\n",
+                f"![Inline]({test_png})",
+            )
+            with (
+                fakefilefactory(
+                    fakepath, content="".join(mailparts)
+                ) as draft_f,
+            ):
+                tree = convert_markdown_to_html(
+                    draft_f, filefactory=fakefilefactory
+                )
+
+            assert tree.subtype == "relative"
+            assert tree.children[0].subtype == "alternative"
+            assert tree.children[1].subtype == "png"
+            written = fakefilefactory.pop()
+            assert tree.children[1].path == written[0]
+            assert written[1].read() == request.urlopen(test_png).read()
+
+        @pytest.mark.converter
+        def test_converter_attribution_to_admonition(
+            self, fakepath, fakefilefactory
+        ):
+            mailparts = (
+                "Regarding whatever",
+                "> blockquote line1",
+                "> blockquote line2",
+                "> ",
+                "> new para with **bold** text",
+            )
+            with fakefilefactory(
+                fakepath, content="\n".join(mailparts)
+            ) as draft_f:
+                convert_markdown_to_html(draft_f, filefactory=fakefilefactory)
+
+            soup = bs4.BeautifulSoup(
+                fakefilefactory[fakepath.with_suffix(".html")].read(),
+                "html.parser",
+            )
+            quote = soup.select_one("div.admonition.quote")
+            assert quote
+            assert (
+                soup.select_one("p.admonition-title").extract().text.strip()
+                == mailparts[0]
+            )
+
+            p = quote.p.extract()
+            assert p.text.strip() == "\n".join(p[2:] for p in mailparts[1:3])
+
+            p = quote.p.extract()
+            assert p.contents[1].name == "strong"
+
+        @pytest.mark.converter
+        def test_converter_attribution_to_admonition_multiple(
+            self, fakepath, fakefilefactory
+        ):
+            mailparts = (
+                "Regarding whatever",
+                "> blockquote line1",
+                "> blockquote line2",
+                "",
+                "Normal text",
+                "",
+                "> continued emailquote",
+                "",
+                "Another email-quote",
+                "> something",
+            )
+            with fakefilefactory(
+                fakepath, content="\n".join(mailparts)
+            ) as draft_f:
+                convert_markdown_to_html(draft_f, filefactory=fakefilefactory)
+
+            soup = bs4.BeautifulSoup(
+                fakefilefactory[fakepath.with_suffix(".html")].read(),
+                "html.parser",
+            )
+            quote = soup.select_one("div.admonition.quote.continued").extract()
+            assert quote
+            assert (
+                quote.select_one("p.admonition-title").extract().text.strip()
+                == mailparts[0]
+            )
+
+            p = quote.p.extract()
+            assert p
+
+            quote = soup.select_one("div.admonition.quote.continued").extract()
+            assert quote
+            assert (
+                quote.select_one("p.admonition-title").extract().text.strip()
+                == mailparts[-2]
+            )
+
+        @pytest.mark.fileio
+        def test_file_class_contextmanager(self, const1, monkeypatch):
+            state = dict(o=False, c=False)
+
+            def fn(t):
+                state[t] = True
+
+            with monkeypatch.context() as m:
+                m.setattr(File, "open", lambda s: fn("o"))
+                m.setattr(File, "close", lambda s: fn("c"))
+                with File() as f:
+                    assert state["o"]
+                    assert not state["c"]
+            assert state["c"]
+
+        @pytest.mark.fileio
+        def test_file_class_no_path(self, const1):
+            with File(mode="w+") as f:
+                f.write(const1, cache=False)
+                assert f.read(cache=False) == const1
+
+        @pytest.mark.fileio
+        def test_file_class_path(self, const1, tmp_path):
+            with File(tmp_path / "file", mode="w+") as f:
+                f.write(const1, cache=False)
+                assert f.read(cache=False) == const1
+
+        @pytest.mark.fileio
+        def test_file_class_cache(self, tmp_path, const1, const2):
+            path = tmp_path / "file"
+            file = File(path, mode="w+")
+            with file as f:
+                f.write(const1, cache=True)
+            with open(path, mode="w") as f:
+                f.write(const2)
+            with file as f:
+                assert f.read(cache=True) == const1
+
+        @pytest.mark.fileio
+        def test_file_class_cache_init(self, const1):
+            file = File(path=None, mode="r", content=const1)
+            with file as f:
+                assert f.read() == const1
+
+        @pytest.mark.fileio
+        def test_file_class_content_or_path(self, fakepath, const1):
+            with pytest.raises(RuntimeError):
+                file = File(path=fakepath, content=const1)
+
+        @pytest.mark.fileio
+        def test_file_class_content_needs_read(self, const1):
+            with pytest.raises(RuntimeError):
+                file = File(mode="w", content=const1)
+
+        @pytest.mark.fileio
+        def test_file_class_write_persists_close(self, const1):
+            f = File(mode="w+")
+            with f:
+                f.write(const1)
+            with f:
+                assert f.read() == const1
+
+        @pytest.mark.fileio
+        def test_file_class_write_resets_read_cache(self, const1, const2):
+            with File(mode="w+", content=const1) as f:
+                assert f.read() == const1
+                f.write(const2)
+                assert f.read() == const2
+
+        @pytest.mark.fileio
+        def test_file_factory(self):
+            fact = FileFactory()
+            f = fact()
+            assert isinstance(f, File)
+            assert len(fact) == 1
+            assert f in fact
+            assert f == fact[0]
+
+        @pytest.mark.fileio
+        def test_fake_file_factory(self, fakepath, fakefilefactory):
+            fact = FakeFileFactory()
+            f = fakefilefactory(fakepath)
+            assert f.path == fakepath
+            assert f == fakefilefactory[fakepath]
+
+        @pytest.mark.fileio
+        def test_fake_file_factory_path_persistence(
+            self, fakepath, fakefilefactory
+        ):
+            f1 = fakefilefactory(fakepath)
+            assert f1 == fakefilefactory(fakepath)

 
 except ImportError:
     pass
 
 except ImportError:
     pass