Add org-attach feature

docs/configuration.org

@@ -7,6 +7,7 @@ This page contains information about all configuration that can be provided to t
 - [[#agenda-settings][Agenda settings]]
 - [[#calendar-settings][Calendar settings]]
 - [[#tags-settings][Tags settings]]
+- [[#attachment-settings][Attachments settings]]
 - [[#mappings][Mappings]]
 - [[#features][Features]]
 - [[#user-interface][User interface]]
@@ -555,6 +556,36 @@ See [[https://orgmode.org/manual/Property-Inheritance.html][Property Inheritance
 - Default: ~{ [':tangle'] = 'no', [':noweb']  = no }~
 Default header args for extracting source code. See [[#extract-source-code-tangle][Extract source code (tangle)]] for more details.
 
+*** org_resource_download_policy
+:PROPERTIES:
+:CUSTOM_ID: org_resource_download_policy
+:END:
+- Type: ='always' | 'prompt' | 'safe' | 'never'=
+- Default: ='prompt'=
+Policy applied to requests to obtain remote resources.
+
+- =always= - Always download remote resources (dangerous!)
+- =prompt= - Prompt before downloading an unsafe resource
+- =safe= - Only download resources allowed by [[#org_safe_remote_resources][org_safe_remote_resources]]
+- =never= - Never download any resources
+
+In Emacs Orgmode, this affects keywords like =#+setupfile= and =#+include=
+on export, =org-persist-write:url=; and =org-attach-url= in non-interactive
+sessions. Nvim Orgmode currently does not use this option, but defines it
+for future use.
+
+*** org_safe_remote_resources
+:PROPERTIES:
+:CUSTOM_ID: org_safe_remote_resources
+:END:
+- Type: =string[]=
+- Default: ={}=
+
+List of regex patterns matching safe URIs. URI regexps are applied to both
+URLs and Org files requesting remote resources. The test uses
+=vim.regex()=, so the regexes are always interpreted as magic and
+case-sensitive.
+
 *** calendar_week_start_day
 :PROPERTIES:
 :CUSTOM_ID: calendar_week_start_day
@@ -1122,6 +1153,171 @@ Using the example above, setting this variable to ={'MYTAG'}=, second
 and third headline would have only =CHILDTAG=, where =MYTAG= would not
 be inherited.
 
+** Attachments settings
+:PROPERTIES:
+:CUSTOM_ID: attachment-settings
+:END:
+
+*** org_attach_id_dir
+:PROPERTIES:
+:CUSTOM_ID: org_attach_id_dir
+:END:
+- Type: =string=
+- Default: ='./data/'=
+
+The directory where attachments are stored. If this is a relative path, it
+will be interpreted relative to the directory where the Org file lives.
+
+*** org_attach_dir_relative
+:PROPERTIES:
+:CUSTOM_ID: org_attach_dir_relative
+:END:
+- Type: =boolean=
+- Default: =false=
+
+If =true=, whenever you add a =DIR= property to a headline, it is added as
+a relative path. The default is to only add absolute paths.
+
+*** org_attach_auto_tag
+:PROPERTIES:
+:CUSTOM_ID: org_attach_auto_tag
+:END:
+- Type: =string=
+- Default: ='ATTACH'=
+
+Tag that is added automatically when attaching files to a headline.
+
+*** org_attach_preferred_new_method
+:PROPERTIES:
+:CUSTOM_ID: org_attach_preferred_new_method
+:END:
+- Type: ='id'|'dir'|'ask'|false=
+- Default: ='id'=
+
+This setting is used when attaching files to nodes that have neither an
+=ID= nor a =DIR= property.
+
+- =id= - create and use an =ID= property
+- =dir= - create and use a =DIR= property
+- =ask= - ask the user which method to use
+- =false= - don't create a property; the user has to define it explicitly before attaching files
+
+*** org_attach_method
+:PROPERTIES:
+:CUSTOM_ID: org_attach_method
+:END:
+- Type: ='cp'|'mv'|'ln'|'lns'=
+- Default: ='cp'=
+
+The preferred method to add files to the attachment directory.
+
+- =mv= - move (rename) the file
+- =cp= - copy the file
+- =ln= - create a hard link; not supported on all systems
+- =lns= - create a symbol link;  not supported on all systems; on Windows, this always creates a /junction/
+
+*** org_attach_copy_directory_create_symlink
+:PROPERTIES:
+:CUSTOM_ID: org_attach_copy_directory_create_symlink
+:END:
+- Type: =boolean=
+- Default: =false=
+
+If =true=, whenever the attachments directory itself is a symlink, and it
+is copied due to the [[https://orgmode.org/manual/Attachment-defaults-and-dispatcher.html*index-C_002dc-C_002da-s][set_directory]] or [[https://orgmode.org/manual/Attachment-defaults-and-dispatcher.html*index-C_002dc-C_002da-S][unset_directory]] action, copy the
+symlink itself. The default is to treat the symlink transparently as
+a directory.
+
+*** org_attach_visit_command
+:PROPERTIES:
+:CUSTOM_ID: org_attach_visit_command
+:END:
+- Type: =string|fun(path: string)=
+- Default: ='edit'=
+
+Command or function used to open a directory. The default opens NetRW if it
+is available.
+
+*** org_attach_use_inheritance
+:PROPERTIES:
+:CUSTOM_ID: org_attach_use_inheritance
+:END:
+- Type: ='always'|'selective'|'never'=
+- Default: ='selective'=
+
+Attachment inheritance for the outline.
+
+Enabling inheritance implies two things:
+1. Attachment links will look through all parent headlines until they find
+   the linked attachment.
+2. Running =attach= inside a node without attachments will operate on the
+   first parent headline that has an attachment.
+
+Possible values are:
+
+- =always= - inherit attachments
+- =selective= - respect [[#org_use_property_inheritance][org_use_property_inheritance]] for the properties =DIR= and =ID=
+- =never= - don't inherit attachments
+
+*** org_attach_store_link_p
+:PROPERTIES:
+:CUSTOM_ID: org_attach_store_link_p
+:END:
+- Type: ='attached' | 'file' | 'original' | false=
+- Default: ='attached'=
+
+If not =false=, store a link with [[#org_store_link][org_store_link]] when attaching a file.
+
+- =attach= - store a =[[attachment:name]]= link
+- =file= - store a =[[file:attach_dir/name]]= link
+- =original= - store a =[[file:original/location]]= link
+
+*** org_attach_archive_delete
+:PROPERTIES:
+:CUSTOM_ID: org_attach_archive_delete
+:END:
+- Type: ='always' | 'ask' | 'never'=
+- Default: ='never'=
+
+Determines whether attachments are deleted automatically whenever a subtree
+is moved to an archive file. The value ='ask'= means to ask the user.
+
+*** org_attach_id_to_path_function_list
+:PROPERTIES:
+:CUSTOM_ID: org_attach_id_to_path_function_list
+:END:
+- Type: =(string | fun(id: string): (string|nil))[]=
+- Default: ={ 'uuid_folder_format', 'ts_folder_format', 'fallback_folder_format' }=
+
+List of functions that are tried sequentially to derive an attachment path
+from an =ID= property. The functions are called with a single =id= argument
+until the return value is an existing folder. The ID format passed to the
+functions is usually defined by [[#org_id_method][org_id_method]].
+
+If no folder has been created yet for the given ID, then the first truthy
+value defines the path of the folder to be created.
+
+The default functions avoid putting all attachment directories directly
+inside [[#org_attach_id_dir][org_attach_id_dir]]. Some file systems have performance issues in
+such scenarios.
+
+Be careful when changing this setting. If you remove a function, previously
+created attachment folders may be no longer mapped correctly and Org may be
+unable to detect them.
+
+*** org_attach_sync_delete_empty_dir
+:PROPERTIES:
+:CUSTOM_ID: org_attach_sync_delete_empty_dir
+:END:
+- Type: ='always'|'ask'|'never'=
+- Default: ='ask'=
+
+Determines whether to delete empty directories during [[https://orgmode.org/manual/Attachment-defaults-and-dispatcher.html*index-C_002dc-C_002da-z][org_attach_sync]].
+
+- =never= - never delete empty directories
+- =ask= - ask the user whether to delete
+- =always= - delete empty directories without asking
+
 ** Mappings
 :PROPERTIES:
 :CUSTOM_ID: mappings
@@ -2032,6 +2228,13 @@ See [[#clocking][Clocking]] for more details.
 - Mapped to: =<leader>obt=
 Tangle current file. See [[#extract-source-code-tangle][Extract source code (tangle)]] for more details.
 
+**** org_attach
+:PROPERTIES:
+:CUSTOM_ID: org_attach
+:END:
+- Mapped to: =<Leader>o<C-A>=
+Open the attach dispatcher. See [[#attachments][Attachments]] for more details.
+
 **** org_show_help
 :PROPERTIES:
 :CUSTOM_ID: org_show_help
@@ -2790,6 +2993,43 @@ Running [[#org_babel_tangle][org_babel_tangle]] will create file =~/org/my_tangl
 =print('Headline 1')=
 =#+end_src=
 
+*** Attachments
+:PROPERTIES:
+:CUSTOM_ID: attachments
+:END:
+
+There is almost complete support for file attachments (Orgmode link:
+[[https://orgmode.org/manual/Attachments.html][Attachments]]). You can use [[#org_attach][org_attach]] to open the dispatcher and attach
+files to an "attachment node" (either a headline or an entire org
+file).
+
+Attaching a file puts it in a directory associated with the attachment node.
+Based on [[#org_attach_preferred_new_method][org_attach_preferred_new_method]], this either uses the =ID= or
+the =DIR= property. See also [[#org_attach_id_dir][org_attach_id_dir]],
+[[#org_attach_dir_relative][org_attach_dir_relative]], [[#org_attach_id_to_path_function_list][org_attach_id_to_path_function_list]] and
+[[#org_attach_use_inheritance][org_attach_use_inheritance]] on how to further customize the attachments
+directory.
+
+Attachment links are supported. A link like =[[attachment:file.txt]]=
+looks up =file.txt= in the current node's attachments directory and opens
+it. Attaching a file stores a link to the attachment. See
+[[#org_attach_store_link_p][org_attach_store_link_p]] on how to configure this behavior.
+
+You can also attach files from a different buffer. The following
+mapping attaches the path under the cursor to the current headline of the
+most recently open org file:
+
+#+begin_src lua
+vim.keymap.set('n', '<Leader>o+', function()
+    local file = vim.fn.expand('<cfile>')
+    local org = require('orgmode')
+    org.attach:attach_to_other_buffer(file)
+end)
+#+end_src
+
+The only missing feature is expansion of attachment links before exporting
+a file with [[#org_export][org_exporting]].
+
 ** User interface
 :PROPERTIES:
 :CUSTOM_ID: user-interface

docs/index.org

@@ -64,6 +64,7 @@ List of available actions:
 - =:Org helpgrep= - Open search agenda view that allows searching through the documentation
 - =:Org agenda {type?}= - Open agenda view by the shortcut, for example =:Org agenda M= will open =tags_todo= view. When =type= is omitted, it opens up Agenda view.
 - =:Org capture {type?}= - Open capture template by the shortcut, for example =:Org capture t=. When =type= is omitted, it opens up Capture prompt.
+- =:Org attach {type?}= - Take attachment action by the shortcut, for example =:Org attach o= will prompt for an attached file to open. When =type= is omitted, it opens up Attach prompt.
 - =:Org install_treesitter_grammar= - Install the treesitter grammar for Orgmode. If installed, prompt to reinstall. Grammar is installed automatically
   on first run, but this is useful in case when there are issues with the grammar.
 - =:Org store_link= - [[file:./configuration.org::#org_store_link][Store link]] to the headline under cursor. Works in both agenda and org files.
@@ -79,3 +80,5 @@ All of the commands above can be executed through the global Lua =Org= variable.
 - =Org.agenda.m()= - Opens =tags= view
 - =Org.capture()= - Opens capture prompt
 - =Org.capture.t()= - Opens capture template for =t= shortcut
+- =Org.attach()= - Opens attach prompt
+- =Org.attach.c()= - Opens attach template for =c= shortcut