* Update fix-duplicates task to 2022_02_10_153119
Also add support for Appeal to AccountMerging#merge_with!
* Update fix-duplicates task to 2022_03_07_094650
* Update fix-duplicates task to 2022_03_09_213005
* Update fix-duplicates task to 2022_03_07_083603
* Update fix-duplicates task to 2022_03_10_060626
* Update fix-duplicates script to 2022_03_07_083603
* Update fix-duplicates task to 2022_03_10_060706
* Update fix-duplicates task to 2022_03_10_060959
* Silence CodeClimate
* Fix null values being included in some indexes
* Update lib/mastodon/migration_helpers.rb
Co-authored-by: Claire <claire.github-309c@sitedethib.com>
* Add documentation link to corruption error message
Co-authored-by: Claire <claire.github-309c@sitedethib.com>
* Add migration tests for hide_network settings migration
* Add tests about suspended/suspended_at
* Add more tests regarding the results of migrations
* Fix migration test regarding stale conflicting remote account
* Add migration tests about AccountConversation
Video files with variable framerates are converted to constant framerate videos
and the output framerate picked by ffmpeg is based on the original file's
container framerate (which can be different from the average framerate).
This means that an input video with variable framerate with about 30 frames per
second on average, but a maximum of 120 fps will be converted to a constant 120
fps file, which won't be processed by other Mastodon servers.
This commit changes it so that input files with VFR and a maximum framerate
above the framerate threshold are converted to VFR files with the maximum frame
rate enforced.
* Add admin option to remove canonical email blocks from a deleted account
* Add tootctl canonical_email_blocks to inspect and remove canonical email blocks
* Add remove orphans to tootctl statuses remove
* Add REINDEX and change option from vacuum to compression-database
* Changed to extract the deletion target of conversations to a temporary table
* Support progress bar and exceptions when media remove
* Add continue option
* Fix compression to compress
* Remove skip_remove_orphans
* Add trending links
* Add overriding specific links trendability
* Add link type to preview cards and only trend articles
Change trends review notifications from being sent every 5 minutes to being sent every 2 hours
Change threshold from 5 unique accounts to 15 unique accounts
* Fix tests
Under certain conditions, files fetched from remotes trigger an error when
being uploaded using OpenStack Swift. This is because in some cases, the
remote server will not return a content-length, so our ResponseWithLimitAdapter
will hold a `nil` value for `#size`, which will lead to an invalid value
for the Content-Length header of the Swift API call.
This commit fixes that by taking the size from the actually-downloaded file
size rather than the upstream-provided Content-Length header value.
In order to work around https://github.com/mastodon/mastodon/issues/16895,
add a warning to .env.production.sample, and change the mastodon:setup rake
task to:
- output a warning if a variable will be interpreted differently by dotenv
and docker-compose
- ensure the printed config is compatible with docker-compose
* Do not block existing users' emails on self-destruct
That is wasteful and unintuitive
* Do not close registrations when running tootctl self-destruct with --dry-run
* Close registrations on self-destruct regardless of known remote accounts
* Fix tootctl self-destruct not sending Deletes for recently-suspended accounts
* Suspend local users even if no remote account is known
* Do not show scary confirmation text if ran with --dry-run
* Switch from unmaintained paperclip to kt-paperclip
* Drop some compatibility monkey-patches not required by kt-paperclip
* Drop media spoof check monkey-patching
It's broken with kt-paperclip and hopefully it won't be needed anymore
* Fix regression introduced by paperclip 6.1.0
* Do not rely on pathname to call FastImage
* Add test for ogg vorbis file with cover art
* Add audio/vorbis to the accepted content-types
This seems erroneous as this would be the content-type for a vorbis stream
without an ogg container, but that's what the `marcel` gem outputs, so…
* Restore missing for_as_default method
* Refactor Attachmentable concern and delay Paperclip's content-type spoof check
Check for content-type spoofing *after* setting the extension ourselves, this
fixes a regression with kt-paperclip's validations being more strict than
paperclip 6.0.0 and rejecting some Pleroma uploads because of unknown
extensions.
* Please CodeClimate
* Add audio/vorbis to the unreliable set
It doesn't correspond to a file format and thus has no extension associated.
* Add account statuses cleanup policy model
* Record last inspected toot to delete to speed up successive calls to statuses_to_delete
* Add service to cleanup a given account's statuses within a budget
* Add worker to go through account policies and delete old toots
* Fix last inspected status id logic
All existing statuses older or equal to last inspected status id must be
kept by the current policy. This is an invariant that must be kept so that
resuming deletion from the last inspected status remains sound.
* Add tests
* Refactor scheduler and add tests
* Add user interface
* Add support for discriminating based on boosts/favs
* Add UI support for min_reblogs and min_favs, rework UI
* Address first round of review comments
* Replace Snowflake#id_at_start with with_random parameter
* Add tests
* Add tests for StatusesCleanupController
* Rework settings page
* Adjust load-avoiding mechanisms
* Please CodeClimate
* Change references to tootsuite/mastodon to mastodon/mastodon
* Remove obsolete test fixture
* Replace occurrences of tootsuite/mastodon with mastodon/mastodon in CHANGELOG
And a few other places
* Fix account deletion sometimes failing because of optimistic locks
In some rare occasions[1], deleting accounts would fail with a
`StaleObjectError` exception.
Indeed, account deletion manually sets the `AccountStat` values without
handling cases where the optimistic locking on `AccountStat` would fail.
To my knowledge, with the rewrite of account counters in #15913, the
`DeleteAccountService` is now the only place that changes the counters in
a way that is not atomic.
Since in this specific case, we do not care about the previous values of the
account counters, it appears we don't need locking at all for this table
anymore.
[1]: https://discourse.joinmastodon.org/t/account-cant-be-deleted/3602
* Bump MAX_SUPPORTED_VERSION in maintenance script
* Fix issues with POSIX::Spawn, Terrapin and Ruby 3.0
Also improve the Terrapin monkey-patch for the stderr/stdout issue.
* Fix keyword argument handling throughout the codebase
* Monkey-patch Paperclip to fix keyword arguments handling in validators
* Change validation_extensions to please CodeClimate
* Bump microformats from 4.2.1 to 4.3.1
* Allow Ruby 3.0
* Add Ruby 3.0 test target to CircleCI
* Add test for admin dashboard warnings
* Fix admin dashboard warnings on Ruby 3.0
* Fix media processing getting stuck on too much stdin/stderr
See thoughtbot/terrapin#5
* Remove dependency on paperclip-av-transcoder gem
* Remove dependency on streamio-ffmpeg gem
* Disable stdin on ffmpeg process
* Update devise-two-factor to unreleased fork for Rails 6 support
Update tests to match new `rotp` version.
* Update nsa gem to unreleased fork for Rails 6 support
* Update rails to 6.1.3 and rails-i18n to 6.0
* Update to unreleased fork of pluck_each for Ruby 6 support
* Run "rails app:update"
* Add missing ActiveStorage config file
* Use config.ssl_options instead of removed ApplicationController#force_ssl
Disabled force_ssl-related tests as they do not seem to be easily testable
anymore.
* Fix nonce directives by removing Rails 5 specific monkey-patching
* Fix fixture_file_upload deprecation warning
* Fix yield-based test failing with Rails 6
* Use Rails 6's index_with when possible
* Use ActiveRecord::Cache::Store#delete_multi from Rails 6
This will yield better performances when deleting an account
* Disable Rails 6.1's automatic preload link headers
Since Rails 6.1, ActionView adds preload links for javascript files
in the Links header per default.
In our case, that will bloat headers too much and potentially cause
issues with reverse proxies. Furhermore, we don't need those links,
as we already output them as HTML link tags.
* Switch to Rails 6.0 default config
* Switch to Rails 6.1 default config
* Do not include autoload paths in the load path
* Improve account counters handling
* Use ActiveRecord::Base::sanitize_sql to pass values instead of interpolating them
Keep using string interpolation for `key` as it is safe and using
“ActiveRecord::Base::sanitize_sql_hash_for_assignment” would require stitching
bits of SQL in a way that is not more easily checked for safety.
* Add migration hook to catch PostgreSQL versions earlier than 9.5
Mastodon::MigrationHelpers has been forked from Gitlab a long time ago, but
Mastodon has never supported using a MySQL database.
Removing MySQL support from Mastodon::MigrationHelpers makes it a little easier
to maintain. In particular, it removes code that would need updating with
Rails 6.
* Use ActiveRecord::Result#to_ary instead of deprecated to_hash
They do the same thing, and to_hash has been removed from Rails 6.1
* Explicitly name polymorphic indexes to workaround a bug in Rails 6.1
cf. https://github.com/rails/rails/issues/41693
* Fix incorrect usage of “foreign_key” in migration script
* Use `ActiveModel::Errors#delete` instead of deprecated clear method
* Fix link headers tests on Rails 6.1
Rails 6.1 adds values to the Link header by default, thus it is not a
LinkHeader object anymore. Fix the test to parse the Link header instead
of assuming it is a LinkHeader.
* Prepare Mastodon for zeitwerk autoloader (Rails 6)
Add inflections and rename/move a few classes.
In particular, app/lib/exceptions.rb and app/lib/sanitize_config.rb
were manually loaded while still in autoload paths.
* Add inflection for Url → URL
* Fix misuse of foreign_type
* Fix use of removed "add_template_helper"
* Use response.media_type instead of response.content_type in tests
* Fix CSV export controller test on Rails 6
Rails 6 sets a "filename*" field in the Content-Disposition header to
explicitly encode the filename as UTF-8.
This changes checks the first part of the Content-Disposition header so
it matches in both Rails 5 and Rails 6.
* Fix emoji formatting with Rails 6
* Make emoji output more idiomatic and robust
* Switch from redis-rails gem to built-in Rails redis cache storage
* Drop dependency on secure_headers, use always_write_cookie instead
* Fix cookies in Tor Hidden Services by moving configuration to application.rb
* Instead of setting always_write_cookie at boot, monkey-patch ActionDispatch
* Added .deepsource.toml
* Removed bad use of `alias`
* Fixed operand order in the binary expression
* Prefixed unused method arguments with an underscore
* Replaced the old OpenSSL algorithmic constants with the newer strings initializers.
* Removed unnecessary UTF-8 encoding comment
* Fix maintenance script not re-indexing some indexes on textual values
Fixes#15475
* Refresh instance view at the end of the maintenance script run
Co-authored-by: Claire <claire.github-309c@sitedethib.com>
* disable NewCops
* update TargetRubyVersion
* Fix Lint/MissingSuper for ActiveModelSerializers::Model
* Fix Lint/MissingSuper for feed
* Fix Lint/FloatComparison
* Do not use instance variables
* Improve Emoji import
Skip macOS '._' shadow files in tar archive to speed up import
* Fix codeclimate format issue with whitespace
* Update lib/mastodon/emoji_cli.rb
suggestions from Gargron to improve comment
Co-authored-by: Eugen Rochko <eugen@zeonfederated.com>
* Update emoji_cli.rb
Remove extraneous comment (macOS-specific comment now with correct line)
Co-authored-by: Eugen Rochko <eugen@zeonfederated.com>
* Fix being able to import more than allowed number of follows
Without this commit, if someone tries importing a second list of accounts to
follow before the first one has been processed, this will queue imports for
the two whole lists, even if they exceed the account's allowed number of
outgoing follows.
This commit changes it so the individual queued imports aren't exempt from
the follow limit check (they remain exempt from the rate-limiting check
though).
* Catch validation errors to not re-queue failed follows
Co-authored-by: Claire <claire.github-309c@sitedethib.com>
* Fix external user creation failing when invite request text is required
Also fixes tootctl-based user creation.
* Add test about invites when invite request text is otherwise required
Co-authored-by: Claire <claire.github-309c@sitedethib.com>
* Fix ResolveAccountService accepting mismatching acct: URI
* Set attributes that should be updated regardless of suspension
* Fix key fetching
* Automatically merge remote accounts with duplicate `uri`
* Add tests
* Add "tootctl accounts fix-duplicates"
Finds duplicate accounts sharing a same ActivityPub `id`, re-fetch them and
merge them under the canonical `acct:` URI.
Co-authored-by: Claire <claire.github-309c@sitedethib.com>
* Add tootctl maintenance fix-duplicates
This tool goes through the database to detect and fix duplicates.
This operation is very slow and may cause data loss (of data that would be
inaccessible without intervention because of the existing index corruptions).
It tries its best to make sensible decisions, and asks the user in some cases.
* Add warning message in db:migrate hook
* Clear Rails cache after being done with database deduplication
Avoids followers hash cache being incorrect, among other things
* Increase DNS timeout from 1 second to 5 seconds for MX check
1 seconds is rather short when using a recursive DNS resolver which
hasn't got a cached result already available. Use 5 seconds instead,
which is the timeout value we use for outgoing HTTP queries.
* Add more precise error messages for invalid e-mail addresses
* Fix contrast calculation for thumbnail color extraction
Luminance calculation was using 0-255 RGB values instead of 0-1 sRGB values,
leading to incorrectly-computed contrast values.
Since we use ColorDiff already, just use its XYZ colorspace conversion code
to get the value.
* Require at least 3:1 contrast for both accent and foreground colors
* Lower required contrast for the accent color
* Change content-type to be always computed from file data
Restore previous behavior, detecting the content-type isn't very
expensive, and some instances may serve files as application/octet-stream
regardless of their true type, making fetching media from them fail, while
it used to work pre-3.2.0.
* Add test
- Change audio files to not be stripped of metadata
- Automatically extract cover art from audio if it exists
- Add `thumbnail` parameter to `POST /api/v1/media`, `POST /api/v2/media` and `PUT /api/v1/media/:id`
- Add `icon` to represent it in attachments in ActivityPub
- Fix `preview_url` containing URL of missing missing image when there is no thumbnail instead of null
- Fix duration of audio not being displayed on public pages until the file is loaded
* Add tootctl email_domains (block|unblock)
* fix codeclimate issues.
* fix codeclimate issues.
* fix codeclimate issues.
* add list subcommand, remove log_action.
* fix codeclimate issues.
* filter duplicate hostnames,ips before block
* rebase from currnet master branch.
rename email_domains_cli.rb to email_domain_blocks_cli.rb .
rename Mastodon::EmailDomainsCLI to Mastodon::EmailDomainBlocksCLI .
rename command email_domains to email-domain-blocks . (Thor recognizes both of - and _ )
rename subcommand block to add .
rename subcommand unblock to remove .
change the color in list subcommand to while for domain or cyan for childlen.
don't use include() in list subcommand.
suppress console output about succeeded entry.
add console output about count of processed/skipped.
remove capitalization in subcommand description.
remove long_desc in subcommand 'remove'.
remove duplicate where in subcommand 'remove'.
* fix codeclimate issue.
* Add emojis:generate_borders Rake task
* Address review
* Border all dark emoji
* Combine stroke with filter to reduce artifacting
* Cleanup Camera with Flash
* Add stroke-linejoin="round"
The previous filter and tweaks were effectively a poor imitation of it.
There are no artifacts for any dark emoji now!
* Set stroke-width using property
This fixes old versions of Firefox.
* Store emoji in string instead of array
* Use separate arguments for each path segment
* Remove "background: black;"
Fix a regression introduced in #13928, caused by TTY::Command building
shell commands by chaining string substitutions.
Ditch TTY::Command and use system instead (both do shell out).
When using one of the docker-compose containers, mastodon:setup will use the
existing .env.production rather than the generated one during the setup steps.
This is because dotenv does not overwrite env variables that are alreayd
defined, and the docker-compose.yml file loads the environment variables
from .env.production.
- Fix not moving original files of custom emojis
- Fix command failing to move any files with S3 storage
- Fix command marking records as upgraded when move failed
Fix#13594
* add emoji export command to cli
* fix codeclimate issues
* add error when no matching category was found
* add other suggestions
* exit 1 when no matching category is found
* changes according to suggestions
* 👀
* RubyNein
Y u always autoformat :c
* Add announcements
Fix#11006
* Add reactions to announcements
* Add admin UI for announcements
* Add unit tests
* Fix issues
- Add `with_dismissed` param to announcements API
- Fix end date not being formatted when time range is given
- Fix announcement delete causing reactions to send streaming updates
- Fix announcements container growing too wide and mascot too small
- Fix `all_day` being settable when no time range is given
- Change text "Update" to "Announcement"
* Fix scheduler unpublishing announcements before they are due
* Fix filter params not being passed to announcements filter
* Fix comments in statuses_cli
The comment for the part of query keeping statuses which have replies was
incorrect, explaining the part of the query kept favourited statuses instead
* Keep statuses favourited by local users in tootctl statuses remove
* Do delete old replies that are not direct interactions with local users
* Skip reblogs of local statuses instead of all reblogs
* Optimize some queries
* Keep old statuses with recent reblogs
* Add option to clear toots from followed accounts too
* Change animated GIF detection to not shell out to ImageMagick
Signed-off-by: Eugen Rochko <eugen@zeonfederated.com>
* Change video encoding parameters to limit to 10800 video frames
Signed-off-by: Eugen Rochko <eugen@zeonfederated.com>
* Limit GIF image size further
Signed-off-by: Eugen Rochko <eugen@zeonfederated.com>
* Always strip metadata from video files
* Fix code style issues
It's possible that after commit callbacks were not firing when
exceptions occurred in the process. Also, the default Sidekiq
strategy does not push indexing jobs immediately, which is not
necessary and could be part of the issue too.
* Add missing locale file for ga and add rake task to check for it
* Update lib/tasks/repo.rake
Co-Authored-By: Yamagishi Kazutoshi <ykzts@desire.sh>
* Fix check-i18n build
* Add "--exclude-suspended" to tootctl domains crawl
This new option ignores any instances suspended server-wide as
well as their associated subdomains. This queries all domain
blocks up front, then runs a regexp on each domain. This improves
performance over what may be the obvious implementation, which is
to ask `DomainBlocks.blocked?(domain)` for each domain -- this
hits the DB many times, slowing things down considerably.
* cleaning up code style
* Compiling regex
* Removing ternary operator
* Add `tootctl preview_cards remove`
* fix code style
* Remove `Scheduler::PreviewCardsCleanupScheduler` file
* fix code style again
Add exclude case where image_file_name is blank
* Added a function to output confirmation if the specified number of days is less than 2 weeks
* Record account suspend/silence time and keep track of domain blocks
* Also unblock users who were suspended/silenced before dates were recorded
* Add tests
* Keep track of suspending date for users suspended through the CLI
* Show accurate number of accounts that would be affected by unsuspending an instance
* Change migration to set silenced_at and suspended_at
* Revert "Also unblock users who were suspended/silenced before dates were recorded"
This reverts commit a015c65d2d1e28c7b7cfab8b3f8cd5fb48b8b71c.
* Switch from using suspended and silenced to suspended_at and silenced_at
* Add post-deployment migration script to remove `suspended` and `silenced` columns
* Use Account#silence! and Account#suspend! instead of updating the underlying property
* Add silenced_at and suspended_at migration to post-migration
* Change account fabricator to translate suspended and silenced attributes
* Minor fixes
* Make unblocking domains always retroactive
* Add blurhash
* Use fallback color for spoiler when blurhash missing
* Federate the blurhash and accept it as long as it's at most 5x5
* Display unknown media attachments as blurhash placeholders
* Improve style of embed actions and spoiler button
* Change blurhash resolution from 3x3 to 4x4
* Improve dependency definitions
* Fix code style issues
* config: Add GITHUB_REPOSITORY for repository name
* config: Add SOURCE_BASE_URL for repository url
* Show source_url and repository name on getting started
* List the actual accounts that would have been culled during a dry run.
Otherwise, the dry run mode is basically useless.
* Prevent unreachable domains from inheriting the previous status code.
* Update CHANGELOG.md for #10460.
* Add REST API for creating an account
The method is available to apps with a token obtained via the client
credentials grant. It creates a user and account records, as well as
an access token for the app that initiated the request. The user is
unconfirmed, and an e-mail is sent as usual.
The method returns the access token, which the app should save for
later. The REST API is not available to users with unconfirmed
accounts, so the app must be smart to wait for the user to click a
link in their e-mail inbox.
The method is rate-limited by IP to 5 requests per 30 minutes.
* Redirect users back to app from confirmation if they were created with an app
* Add tests
* Return 403 on the method if registrations are not open
* Require agreement param to be true in the API when creating an account
This allowed you to brick your system when running that command, because the accounts would continue to advertise the old public key, but sign things with the new one
- Some associations were missing from the clean-up
- Some attributes were not reset on suspension
- Skip federation and streaming deletes when purging a dead domain
- Move account association definitions to concern
Just the color is not enough change since not everyone uses colored
terminals.
Touching the account makes it so that the account is not in the
threshold window in case of running again
Leave `tootctl accounts cull` to simply check removed accounts from
live domains, and skip temporarily unavailable domains, while listing
them in the final output for further action.
Add `tootctl domains purge DOMAIN` to be able to purge a domain from
that list manually
* Move more tasks to tootctl
- tootctl feeds build
- tootctl feeds clear
- tootctl accounts refresh
Clean up exit codes and help messages
* Move user modifying to tootctl
* Improve user modification through CLI, rename commands
add -> create
mod -> modify
del -> delete
To remove ambiguity
* Fix code style issues
* Fix not being able to unset admin/mod role
* Fix that can't delete media files even if "tootctl media remove" execute when "--background" not attached.
* Revert
This reverts commit 5aa7e09645b27bae38a26030148b23e553ee2662.
* Change to obtain and pass all columns when "--background" option is false.
* If an Update is signed with known key, skip re-following procedure
Because it means the remote actor did *not* lose their database
* Add CLI method for rotating keys
bin/tootctl accounts rotate [USERNAME]
Generates a new RSA key per account and sends out an Update activity
signed with the old key.
* Key rotation: Space out Update fan-outs every 5 minutes per 1000 accounts
* Skip suspended accounts in key rotation
Adopted from GitLab CE. Generate new migration with:
rails g post_deployment_migration name_of_migration_here
By default they are run together with db:migrate. To not run them,
the env variable SKIP_POST_DEPLOYMENT_MIGRATIONS must be set
Code by Yorick Peterse <yorickpeterse@gmail.com>, see also:
83c8241160
To improve the way super tall or super ride images are treated, the
numbers remain the same, 1280x1280 and 400x400, but if an image
is less in one dimension than the other, the other can become larger
Thanks to @WAHa_06x36@mastodon.social for the tip
* Speed up some rake tasks by moving execution to Sidekiq
mastodon:media:remove_silenced
mastodon:media:remove_remote
mastodon:media:redownload_avatars
mastodon:feeds:build
* Fix code style issue
* Revert "Fixes/do not override timestamps (#7331)"
This reverts commit 581a5c9d29.
* Document Snowflake ID corner-case a bit more
Snowflake IDs are used for two purposes: making object identifiers harder to
guess and ensuring they are in chronological order. For this reason, they
are based on the `created_at` attribute of the object.
Unfortunately, inserting items with older snowflakes IDs will break the
assumption of consumers of the paging APIs that new items will always have
a greater identifier than the last seen one.
* Add `override_timestamps` virtual attribute to not correlate snowflake ID with created_at
* No need to re-require sidekiq plugins, they are required via Gemfile
* Add derailed_benchmarks tool, no need to require TTY gems in Gemfile
* Replace ruby-oembed with FetchOEmbedService
Reduce startup by 45382 allocated objects
* Remove preloaded JSON-LD in favour of caching HTTP responses
Reduce boot RAM by about 6 MiB
* Fix tests
* Fix test suite by stubbing out JSON-LD contexts
* Add support for separate Redis for cache
CACHE_REDIS_URL to allow using a different Redis server for cache
purposes, with cache-specific configuration such as key eviction
* Fix code style issues
Comparison was downcasing only one side, therefore if previously
existing account had a non-lowercase spelling, it would be ignored
when checking for duplicates.
New rake task `mastodon:maintenance:find_duplicate_usernames` will
help find constraint violations that might have occured from the
presence of this bug.
Bump version to 2.3.3
Claire
Eugen Rochko
Holger
Rens Groothuijsen
Josh Soref
Jeong Arm
Takeshi Umeda
OSAMU SATO
rinsuki
Ikko Ashimine
abcang
Stanislas
Justin Tracey
Cecylia Bocovich
Shubhendra Singh Chauhan
ThibG
luigi
Sophie Parker
Y.Yamashiro
dependabot[bot]
tateisu
leo60228
Stanislas
Hanage999
Lerk
D Anzorge
Marcin Cieślak
Gomasy
trwnh
Yamagishi Kazutoshi
Nathaniel Suchy
Darius Kazemi
dependabot-preview[bot]
mayaeh
Clar Fon
Ushitora Anqou
Sho Kusano
Ben Lubar
Renato "Lond" Cerqueira
Sascha
ashleyhull-versent
luzpaz
nightpool
Quint Guvernator
M Somerville
Immae
MIYAGI Hikaru
Alejandro Martinez Ruiz
David Baucum