GNU bug report logs - #77731
[PATCH] Add yank-media-handler for copied files from file manager

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Message #5 received at submit <at> debbugs.gnu.org (full text, mbox):

From: Visuwesh <visuweshm <at> gmail.com>
To: bug-gnu-emacs <at> gnu.org
Subject: [PATCH] Add yank-media-handler for copied files from file manager
Date: Fri, 11 Apr 2025 14:58:32 +0530

[Message part 1 (text/plain, inline)]

[ This has been sitting in my drafts folder for many months now.  ]

Attached patch adds a yank-media-handler to message-mode to attach files
copied/cut from a file manager.  I tested this patch using pcmanfm and
xfe.  The regexp for the media-type was chosen after the blogpost [1],
pcmanfm in particular sets the media-type to
x-special/gnome-copied-files.

I strip the null byte in the split-string call in the handler because
pcmanfm adds a null byte at the end of clipboard selection.  I don't
know if this is the case with other file managers.

I also cannot find the spec of this clipboard type but [2] and pcmanfm
suggests that the selection is

    OPERATION
    file://FILE1
    file://FILE2...

where OPERATION is either cut or copy, and the rest of the lines are
links to the files.  I do the same as what Org does to parse the above.

1. https://larsee.com/blog/2019/05/clipboard-files/
2. https://indigo.re/posts/2021-12-21-clipboard-data.html

In GNU Emacs 30.0.50 (build 7, x86_64-pc-linux-gnu, X toolkit, Xaw
 scroll bars) of 2023-09-10 built on astatine
Repository revision: af1e860570191014d94484d6944348b1766ba59f
Repository branch: master
Windowing system distributor 'The X.Org Foundation', version 11.0.12101008
System Description: Debian GNU/Linux trixie/sid

Configured using:
 'configure --with-sound=alsa --with-x-toolkit=lucid --with-json
 --without-xaw3d --without-gconf --without-libsystemd --without-cairo'

[0001-Add-yank-media-handler-for-copied-files-from-file-ma.patch (text/patch, attachment)]

Message #8 received at 77731 <at> debbugs.gnu.org (full text, mbox):

From: Eli Zaretskii <eliz <at> gnu.org>
To: Visuwesh <visuweshm <at> gmail.com>, Po Lu <luangruo <at> yahoo.com>
Cc: 77731 <at> debbugs.gnu.org
Subject: Re: bug#77731: [PATCH] Add yank-media-handler for copied files from
 file manager
Date: Fri, 11 Apr 2025 14:31:06 +0300

> From: Visuwesh <visuweshm <at> gmail.com>
> Date: Fri, 11 Apr 2025 14:58:32 +0530
> 
> [ This has been sitting in my drafts folder for many months now.  ]
> 
> Attached patch adds a yank-media-handler to message-mode to attach files
> copied/cut from a file manager.  I tested this patch using pcmanfm and
> xfe.  The regexp for the media-type was chosen after the blogpost [1],
> pcmanfm in particular sets the media-type to
> x-special/gnome-copied-files.

Thanks, but copy/paste operations on files should first and foremost
be supported in Dired, no?  Limiting such support to message-mode
seems too narrow and much less useful than it could be, let alone what
users would expect.

Can we support this in Dired?

> I strip the null byte in the split-string call in the handler because
> pcmanfm adds a null byte at the end of clipboard selection.  I don't
> know if this is the case with other file managers.
> 
> I also cannot find the spec of this clipboard type but [2] and pcmanfm
> suggests that the selection is
> 
>     OPERATION
>     file://FILE1
>     file://FILE2...
> 
> where OPERATION is either cut or copy, and the rest of the lines are
> links to the files.  I do the same as what Org does to parse the above.
> 
> 1. https://larsee.com/blog/2019/05/clipboard-files/
> 2. https://indigo.re/posts/2021-12-21-clipboard-data.html

I wonder if this is too specific to the specific file managers you
tested this with.  If it is, should we try to support more file
managers?

> +(defun message--yank-media-copied-files-handler (_ data)
> +  "Attach files copied/cut from the file manager.

The name and the doc string should be more specific to the file
managers for which this is supposed to work.  I doubt that these
details are general enough to say that any file manager capable of
copy/pasting files will behave like that.

Btw, isn't copy/paste of files similar or maybe even equivalent to
drag-n-drop?  If so, perhaps a better way would be to use the DND
machinery we have in Emacs?  Adding Po Lu in case he has opinions or
comments about this.

Message #11 received at 77731 <at> debbugs.gnu.org (full text, mbox):

From: Visuwesh <visuweshm <at> gmail.com>
To: Eli Zaretskii <eliz <at> gnu.org>
Cc: Po Lu <luangruo <at> yahoo.com>, 77731 <at> debbugs.gnu.org
Subject: Re: bug#77731: [PATCH] Add yank-media-handler for copied files from
 file manager
Date: Fri, 11 Apr 2025 17:14:36 +0530

[வெள்ளி ஏப்ரல் 11, 2025] Eli Zaretskii wrote:

>> From: Visuwesh <visuweshm <at> gmail.com>
>> Date: Fri, 11 Apr 2025 14:58:32 +0530
>> 
>> [ This has been sitting in my drafts folder for many months now.  ]
>> 
>> Attached patch adds a yank-media-handler to message-mode to attach files
>> copied/cut from a file manager.  I tested this patch using pcmanfm and
>> xfe.  The regexp for the media-type was chosen after the blogpost [1],
>> pcmanfm in particular sets the media-type to
>> x-special/gnome-copied-files.
>
> Thanks, but copy/paste operations on files should first and foremost
> be supported in Dired, no?  Limiting such support to message-mode
> seems too narrow and much less useful than it could be, let alone what
> users would expect.
>
> Can we support this in Dired?

Sure, I can prepare a patch that would copy/rename the file if the user
has copy/cut the file from her file manager.  I have code for this
living in my init file.

>> I strip the null byte in the split-string call in the handler because
>> pcmanfm adds a null byte at the end of clipboard selection.  I don't
>> know if this is the case with other file managers.
>> 
>> I also cannot find the spec of this clipboard type but [2] and pcmanfm
>> suggests that the selection is
>> 
>>     OPERATION
>>     file://FILE1
>>     file://FILE2...
>> 
>> where OPERATION is either cut or copy, and the rest of the lines are
>> links to the files.  I do the same as what Org does to parse the above.
>> 
>> 1. https://larsee.com/blog/2019/05/clipboard-files/
>> 2. https://indigo.re/posts/2021-12-21-clipboard-data.html
>
> I wonder if this is too specific to the specific file managers you
> tested this with.  If it is, should we try to support more file
> managers?

I believe covering x-special/gnome-copied-files will cover a large
ground of file managers.  Obviously, I have no idea how to support file
managers in MacOS or Windows.

>> +(defun message--yank-media-copied-files-handler (_ data)
>> +  "Attach files copied/cut from the file manager.
>
> The name and the doc string should be more specific to the file
> managers for which this is supposed to work.  I doubt that these
> details are general enough to say that any file manager capable of
> copy/pasting files will behave like that.

See above.  I can say that it works with pcmanfm, xfe, and thunar if my
memory serves right.

> Btw, isn't copy/paste of files similar or maybe even equivalent to
> drag-n-drop?

They essentially serve to perform the same function in most cases, yes.

> If so, perhaps a better way would be to use the DND machinery we have
> in Emacs?  Adding Po Lu in case he has opinions or comments about
> this.

As in, call the relevant function in dnd-protocol-alist for ^file:///?
This hasn't crossed my mind.  I am not opposed to this idea.

Message #14 received at 77731 <at> debbugs.gnu.org (full text, mbox):

From: Po Lu <luangruo <at> yahoo.com>
To: Eli Zaretskii <eliz <at> gnu.org>
Cc: 77731 <at> debbugs.gnu.org, Visuwesh <visuweshm <at> gmail.com>
Subject: Re: bug#77731: [PATCH] Add yank-media-handler for copied files from
 file manager
Date: Fri, 11 Apr 2025 20:10:45 +0800

Eli Zaretskii <eliz <at> gnu.org> writes:

>> From: Visuwesh <visuweshm <at> gmail.com>
>> Date: Fri, 11 Apr 2025 14:58:32 +0530
>> 
>> [ This has been sitting in my drafts folder for many months now.  ]
>> 
>> Attached patch adds a yank-media-handler to message-mode to attach files
>> copied/cut from a file manager.  I tested this patch using pcmanfm and
>> xfe.  The regexp for the media-type was chosen after the blogpost [1],
>> pcmanfm in particular sets the media-type to
>> x-special/gnome-copied-files.
>
> Thanks, but copy/paste operations on files should first and foremost
> be supported in Dired, no?  Limiting such support to message-mode
> seems too narrow and much less useful than it could be, let alone what
> users would expect.
>
> Can we support this in Dired?

+1.

>> I strip the null byte in the split-string call in the handler because
>> pcmanfm adds a null byte at the end of clipboard selection.  I don't
>> know if this is the case with other file managers.
>> 
>> I also cannot find the spec of this clipboard type but [2] and pcmanfm
>> suggests that the selection is
>> 
>>     OPERATION
>>     file://FILE1
>>     file://FILE2...
>> 
>> where OPERATION is either cut or copy, and the rest of the lines are
>> links to the files.  I do the same as what Org does to parse the above.
>> 
>> 1. https://larsee.com/blog/2019/05/clipboard-files/
>> 2. https://indigo.re/posts/2021-12-21-clipboard-data.html
>
> I wonder if this is too specific to the specific file managers you
> tested this with.  If it is, should we try to support more file
> managers?
>
>> +(defun message--yank-media-copied-files-handler (_ data)
>> +  "Attach files copied/cut from the file manager.
>
> The name and the doc string should be more specific to the file
> managers for which this is supposed to work.  I doubt that these
> details are general enough to say that any file manager capable of
> copy/pasting files will behave like that.

> Btw, isn't copy/paste of files similar or maybe even equivalent to
> drag-n-drop?  If so, perhaps a better way would be to use the DND
> machinery we have in Emacs?  Adding Po Lu in case he has opinions or
> comments about this.

Regrettably not, since the formats concerned differ subtly and DND gives
a weight to negotiating actions on dropped data that is undue for a
simple copy/paste operation.  The selection formats you must recognize
are `text/uri-list' (which is identical to its Xdnd variant), FILE_NAME,
and FILE, which are NULL-separated lists of strings, and numerous ad hoc
formats defined by file managers and desktop environments.

If you like, you may implement a rough draft that functions
satisfactorily with whatever file managers you test, and I shall supply
its deficiencies as best I can.

Message #17 received at 77731 <at> debbugs.gnu.org (full text, mbox):

From: Visuwesh <visuweshm <at> gmail.com>
To: Po Lu <luangruo <at> yahoo.com>
Cc: Eli Zaretskii <eliz <at> gnu.org>, 77731 <at> debbugs.gnu.org
Subject: Re: bug#77731: [PATCH] Add yank-media-handler for copied files from
 file manager
Date: Fri, 11 Apr 2025 18:41:08 +0530

[வெள்ளி ஏப்ரல் 11, 2025] Po Lu via "Bug reports for GNU Emacs, the Swiss army knife of text editors" wrote:

>> The name and the doc string should be more specific to the file
>> managers for which this is supposed to work.  I doubt that these
>> details are general enough to say that any file manager capable of
>> copy/pasting files will behave like that.
>
>> Btw, isn't copy/paste of files similar or maybe even equivalent to
>> drag-n-drop?  If so, perhaps a better way would be to use the DND
>> machinery we have in Emacs?  Adding Po Lu in case he has opinions or
>> comments about this.
>
> Regrettably not, since the formats concerned differ subtly and DND gives
> a weight to negotiating actions on dropped data that is undue for a
> simple copy/paste operation.  The selection formats you must recognize
> are `text/uri-list' (which is identical to its Xdnd variant), FILE_NAME,
> and FILE, which are NULL-separated lists of strings, and numerous ad hoc
> formats defined by file managers and desktop environments.

What's wrong with doing the following?

    (defun message--yank-media-copied-files-handler (_ data)
      "Attach files copied/cut from the file manager.
    DATA is a string where the first line is the operation to
    perform: copy or cut.  Rest are file: links.  The operation is
    always ignored, and the files are only attached."
      (let ((files (split-string data "[\0\n\r]" t)))
        (dnd-handle-multiple-urls (selected-window)
                                  (cdr files)
                                  (pcase (car files)
                                    (`"copy" 'copy)
                                    (`"cut" 'move)
                                    (_ 'private)))))

It calls mml-dnd-attach-file in message-mode buffer.

> If you like, you may implement a rough draft that functions
> satisfactorily with whatever file managers you test, and I shall supply
> its deficiencies as best I can.

Considering that text/uri-list and friends seem to be considered in
others part of the code, is there a function that would parse its
format?

Message #20 received at 77731 <at> debbugs.gnu.org (full text, mbox):

From: Po Lu <luangruo <at> yahoo.com>
To: Visuwesh <visuweshm <at> gmail.com>
Cc: Eli Zaretskii <eliz <at> gnu.org>, 77731 <at> debbugs.gnu.org
Subject: Re: bug#77731: [PATCH] Add yank-media-handler for copied files from
 file manager
Date: Sat, 12 Apr 2025 09:28:57 +0800

Visuwesh <visuweshm <at> gmail.com> writes:

> [வெள்ளி ஏப்ரல் 11, 2025] Po Lu via "Bug reports for GNU Emacs, the Swiss army knife of text editors" wrote:
>
>>> The name and the doc string should be more specific to the file
>>> managers for which this is supposed to work.  I doubt that these
>>> details are general enough to say that any file manager capable of
>>> copy/pasting files will behave like that.
>>
>>> Btw, isn't copy/paste of files similar or maybe even equivalent to
>>> drag-n-drop?  If so, perhaps a better way would be to use the DND
>>> machinery we have in Emacs?  Adding Po Lu in case he has opinions or
>>> comments about this.
>>
>> Regrettably not, since the formats concerned differ subtly and DND gives
>> a weight to negotiating actions on dropped data that is undue for a
>> simple copy/paste operation.  The selection formats you must recognize
>> are `text/uri-list' (which is identical to its Xdnd variant), FILE_NAME,
>> and FILE, which are NULL-separated lists of strings, and numerous ad hoc
>> formats defined by file managers and desktop environments.
>
> What's wrong with doing the following?
>
>     (defun message--yank-media-copied-files-handler (_ data)
>       "Attach files copied/cut from the file manager.
>     DATA is a string where the first line is the operation to
>     perform: copy or cut.  Rest are file: links.  The operation is
>     always ignored, and the files are only attached."
>       (let ((files (split-string data "[\0\n\r]" t)))
>         (dnd-handle-multiple-urls (selected-window)
>                                   (cdr files)
>                                   (pcase (car files)
>                                     (`"copy" 'copy)
>                                     (`"cut" 'move)
>                                     (_ 'private)))))
>
> It calls mml-dnd-attach-file in message-mode buffer.

It expects and respects options specific to drag and drop.  `(car
files)' is also certainly not guaranteed to designate the action to
take.

> Considering that text/uri-list and friends seem to be considered in
> others part of the code, is there a function that would parse its
> format?

Not that I'm aware of.

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