Don't show a contact as verified if their key changed in the meantime
If a contact's key changed since the verification, then it's very
unlikely that they still have the old, verified key. So, don't show them
as verified anymore.
This also means that you can't add a contact like this to a verified
group, which is good.
The documentation actually already described this (new) behavior:
```rust
/// and if the key has not changed since this verification.
```
so, this adapts the code to the documentation.
It can be used e.g. as a default in the file saving dialog. Also display the original filename in
the message info. For these purposes add Param::Filename in addition to Param::File and use it as an
attachment filename in sent emails.
Opening the same account (context) from multiple processes is dangerous, can result in duplicate
downloads of the same message etc. Same for account manager, attempts to modify the same
accounts.toml even if done atomically with may result in corrupted files as atomic replacement
procedure does not expect that multiple processes may write to the same temporary file.
accounts.toml cannot be used as a lockfile because it is replaced during atomic update. Therefore, a
new file next to accounts.toml is needed to prevent starting second account manager in the same
directory.
But iOS needs to be able to open accounts from multiple processes at the same time. This is required
as the "share-to-DC extension" is a separate process by iOS design -- this process may or may not be
started while the main app is running. Accounts are not altered however by this extension, so let's
add to the `Accounts::new()` constructor an `rdwr` parameter which allows to read the accounts
config w/o locking the lockfile.
Webxdc update messages may contain
long lines that get hard-wrapped
and may corrupt JSON if the message
is not encrypted.
base64-encode the update part
to avoid hard wrapping.
This is not necessary for encrypted
messages, but does not introduce
size overhead as OpenPGP messages
are compressed.
Correctly handle messages with old timestamps for verified chats:
* They must not be sorted over a protection-changed info message
* If they change the protection, then they must not be sorted over existing other messages, because then the protection-changed info message would also be above these existing messages.
This PR fixes this:
1. Even seen messages can't be sorted into already-noticed messages anymore. **This also changes DC's behavior in the absence of verified 1:1 chats**. Before this PR, messages that are marked as seen when they are downloaded will always be sorted by their timestamp, even if it's very old.
2. protection-changed info messages are always sorted to the bottom.
**Edit:**
3. There is an exception to rule 1: Outgoing messages are still allowed to be sorted purely by their timestamp, and don't influence old messages. This is to the problem described at [*].
Together, these rules also make sure that the protection-changed info message is always right above the message causing the change.
[*] If we receive messages from two different folders, e.g. `Sent` and `Inbox`, then this will lead to wrong message ordering in many cases. I need to think about this more, or maybe someone else has an idea. One new idea that came to my mind is:
* Always sort noticed messages under the newest info message (this PR sorts them under the newest noticed message, master sorts them purely by their sent timestamp)
* Always sort unnoticed messages under the newest noticed message (that's the same behavior as in this PR and on master)
* Always sort protection-changed info messages to the bottom (as in this PR)
However, after a talk with @link2xt we instead decided to add rule 3. (see above) because it seemed a little bit easier.
The test checks that if webxdc update is too large to
download with the current `download_limit`,
it is applied afterwards when the user manually downloads the update message.
tokio-tar 0.3.0 prints message "create_dir_all ..." to stdout during import.
tokio-tar 0.3.1 has removed this debug output which broke stdio JSON-RPC protocol.
