Various methods of Buffer should be rather methods of SharedBuffer. This
commit doesn't move all of them to SharedBuffer yet, only those that
need to be moved to SharedBuffer in order to be able to request creating
or removing backups in other SharedBuffer methods.
Instead of calculating the hash of the buffer every time Modified() is
called, do that every time b.isModified is updated (i.e. every time the
buffer is modified) and set b.isModified value accordingly.
This change means that the hash will be recalculated every time the user
types or deletes a character. But that is what already happens anyway,
since inserting or deleting characters triggers redrawing the display,
in particular redrawing the status line, which triggers Modified() in
order to show the up-to-date modified/unmodified status in the status
line. And with this change, we will be able to check this status
more than once during a single "handle event & redraw" cycle, while
still recalculating the hash only once.
- extract the open logic into `openFile()` and return a `wrappedFile`
- extract the closing logic into `Close()` and make a method of `wrappedFile`
- rename `writeFile()` into `Write()` and make a method of `wrappedFile`
This allows to use the split parts alone while keeping overwriteFile() as simple
interface to use all in a row.
When saving a file with sudo fails (e.g. if we set `sucmd` to a
non-existent binary, e.g. `set sucmd aaa`), we erroneously return
success instead of the error, as a result we report to the user that
that the file has been successfully saved. Fix it.
When we are saving a file with sudo, if we interrupt sudo via Ctrl-c,
it doesn't just kill sudo, it kills micro itself.
The cause is the same as in the issue #2612 for RunInteractiveShell()
which was fixed by #3357. So fix it the same way as in #3357.
Saving a buffer every time without even checking if it was modified
(i.e. even when the user is not editing the buffer) is wasteful,
especially if the autosave period is set to a short value.
Similarly to the crash fixed by #2967, which happens if sudo failed,
a crash also happens when sudo even fails to start. The reason for
the crash is also similar: nil dereference of screen.Screen caused by
the fact that we do not restore temporarily disabled screen.
To reproduce this crash, set the `sucmd` option to some non-existing
command, e.g. `aaa`, and try to save a file with root privileges.
On modern Linux systems, it can take 30 seconds for
the data to actually hit the disk (check
/proc/sys/vm/dirty_expire_centisecs).
If the computer crashes in those 30 seconds, the user
may end up with an empty file as seen here:
https://github.com/neovim/neovim/issues/9888
This is why editors like vim and nano call
the fsync syscall after they wrote the file.
This syscall is available as file.Sync() in Go.
Running strace against micro shows that fsync is
called as expected:
$ strace -f -p $(pgrep micro) -e fsync
strace: Process 3284344 attached with 9 threads
[pid 3284351] fsync(8) = 0
Also, we now catch errors returned from w.Flush().
