On Thu, 24 Apr 2014, Austin Clements <amdra...@mit.edu> wrote:
> Quoth Mark Walters on Apr 24 at 11:46 am:
>>
>> On Mon, 21 Apr 2014, Austin Clements <amdra...@mit.edu> wrote:
>> > (The actual code change here is small, but requires re-indenting
>> > existing code.)
>> > ---
>> > emacs/notmuch-lib.el | 52
>> > ++++++++++++++++++++++++++++++----------------------
>> > 1 file changed, 30 insertions(+), 22 deletions(-)
>> >
>> > diff --git a/emacs/notmuch-lib.el b/emacs/notmuch-lib.el
>> > index fc67b14..fee8512 100644
>> > --- a/emacs/notmuch-lib.el
>> > +++ b/emacs/notmuch-lib.el
>> > @@ -503,33 +503,39 @@ (defun notmuch-parts-filter-by-type (parts type)
>> > (lambda (part) (notmuch-match-content-type (plist-get part
>> > :content-type) type))
>> > parts))
>> >
>> > -(defun notmuch-get-bodypart-binary (msg part process-crypto)
>> > +(defun notmuch-get-bodypart-binary (msg part process-crypto &optional
>> > cache)
>> > "Return the unprocessed content of PART in MSG as a unibyte string.
>> >
>> > This returns the \"raw\" content of the given part after content
>> > transfer decoding, but with no further processing (see the
>> > discussion of --format=raw in man notmuch-show). In particular,
>> > this does no charset conversion."
>> > - (let ((args `("show" "--format=raw"
>> > - ,(format "--part=%d" (plist-get part :id))
>> > - ,@(when process-crypto '("--decrypt"))
>> > - ,(notmuch-id-to-query (plist-get msg :id)))))
>> > - (with-temp-buffer
>> > - ;; Emacs internally uses a UTF-8-like multibyte string
>> > - ;; representation by default (regardless of the coding system,
>> > - ;; which only affects how it goes from outside data to this
>> > - ;; internal representation). This *almost* never matters.
>> > - ;; Annoyingly, it does matter if we use this data in an image
>> > - ;; descriptor, since Emacs will use its internal data buffer
>> > - ;; directly and this multibyte representation corrupts binary
>> > - ;; image formats. Since the caller is asking for binary data, a
>> > - ;; unibyte string is a more appropriate representation anyway.
>> > - (set-buffer-multibyte nil)
>> > - (let ((coding-system-for-read 'no-conversion))
>> > - (apply #'call-process notmuch-command nil '(t nil) nil args)
>> > - (buffer-string)))))
>> > -
>> > -(defun notmuch-get-bodypart-text (msg part process-crypto)
>> > + (let ((data (plist-get part :binary-content)))
>> > + (when (not data)
>> > + (let ((args `("show" "--format=raw"
>> > + ,(format "--part=%d" (plist-get part :id))
>> > + ,@(when process-crypto '("--decrypt"))
>> > + ,(notmuch-id-to-query (plist-get msg :id)))))
>> > + (with-temp-buffer
>> > + ;; Emacs internally uses a UTF-8-like multibyte string
>> > + ;; representation by default (regardless of the coding
>> > + ;; system, which only affects how it goes from outside data
>> > + ;; to this internal representation). This *almost* never
>> > + ;; matters. Annoyingly, it does matter if we use this data
>> > + ;; in an image descriptor, since Emacs will use its internal
>> > + ;; data buffer directly and this multibyte representation
>> > + ;; corrupts binary image formats. Since the caller is
>> > + ;; asking for binary data, a unibyte string is a more
>> > + ;; appropriate representation anyway.
>> > + (set-buffer-multibyte nil)
>> > + (let ((coding-system-for-read 'no-conversion))
>> > + (apply #'call-process notmuch-command nil '(t nil) nil args)
>> > + (setq data (buffer-string)))))
>> > + (when cache
>> > + (plist-put part :binary-content data)))
>> > + data))
>>
>> I am a little puzzled by this but that could be lack of familiarity with
>> elisp. As far as I can see plist-put will sometimes modify the original
>> plist and sometimes return a new plist. If the latter happens then I
>> think it works out as if we hadn't cached anything as the part passed to
>> the function is unmodified. That might not matter in this case (though I
>> find the lack of determinism disturbing).
>>
>> Or is something else going on?
>
> No, your familiarity with Elisp serves you well. I'm completely
> cheating here. According to the specification of plist-put, it's
> allowed to return a new list but in reality this only happens when the
> original plist is nil. We lean on this already all over the
> notmuch-emacs code, but maybe that doesn't excuse me adding one more
> cheat.
>
> I could add a comment here explaining what's going on, I could
> manually do the list insertion in a way that's guaranteed to mutate it
> in place, or I could add a nil :binary-content property when parts are
> created (since plist-put is guaranteed to mutate existing keys in
> place).
I think a comment is fine.
(Incidentally what is the best way of telling if emacs has changed an
object or returned a new one for other commands? Something like (setq
oldobject object) (setq object (operation-on object)) (if (eq object
oldobject) ... ))
Also, I think the function should have a comment about the lifetime of
the caching. I think in some cases the addition of :binary-content could
occur on load and thus the plist with binary content added would get
saved in the buffer when the msg plist was saved as a
text-property. However, maybe in other cases this gets called after the
initial insertion and thus the cached value is just used during this
operation on msg? Sorry that is a little incoherent as I haven't checked
all callers.
Best wishes
Mark
>> Best wishes
>>
>> Mark
>>
>>
>>
>> > +
>> > +(defun notmuch-get-bodypart-text (msg part process-crypto &optional cache)
>> > "Return the text content of PART in MSG.
>> >
>> > This returns the content of the given part as a multibyte Lisp
>> > @@ -546,7 +552,9 @@ (defun notmuch-get-bodypart-text (msg part
>> > process-crypto)
>> > (npart (apply #'notmuch-call-notmuch-sexp args)))
>> > (setq content (plist-get npart :content))
>> > (when (not content)
>> > - (error "Internal error: No :content from %S" args))))
>> > + (error "Internal error: No :content from %S" args)))
>> > + (when cache
>> > + (plist-put part :content content)))
>> > content))
>> >
>> > ;; Workaround: The call to `mm-display-part' below triggers a bug in
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