NAME

Padre::Autosave - autosave and recovery mechanism for Padre

SYNOPSIS

my $autosave = Padre:Autosave->new(db => 'path/to/database');
$autosave->save_file($path, $type, $data, $timestamp) = @_;

DESCRIPTION

The longer autosave plan

The following is just a plan that is currently shelved as some people on the Padre development list think this is not ncessary and one should use a real version control for this anyway.

So I leave it here for now, for future exploration.

I'd like to provide autosave with some history and recovery service.

While I am writing this for Padre I'll make the code separate so others can use it.

An sqlite database will be used for this but theoretically any database could be used. Event plain filesystem.

Basically this will provide a versioned filesystem with metadata and autocleanup.

Besides the content of the file we need to save some meta data: - path to the file will be the unique identifyer - timestamp - type of save (initial, autosave, usersave, external)

When opening a file for the first time it is saved in the database.(initial)

Every N seconds files that are not currently in "saved" situation are autosaved in the database making sure that they are only saved if they differ from the previous state. (autosave)

Evey time a file is saved it is also saved to the database. (usersave) Before reloading a file we autosave it. (autosave)

Every time we notice that a file was changed on the disk if the user decides to overwrite it we also save the (external) changed file.

Before autosaving a file we make sure it has not changed since the last autosave.

In order to make sure the database does not get too big we setup a cleaning mechanizm that is executed once in a while. There might be several options but for now: 1) Every entry older than N days will be deleted.

Based on the database we'll be able to provide the user recovery in case of crash or accidental overwrite.

When opening padre we should check if there are files in the database that the last save was NOT usersave and offer recovery.

When opening a file we should also check how is it related to the last save in the database.

For buffers that were never saved and so have no filenames we should have some internal identifier in Padre and use that for the autosave till the first usersave.

The same mechanizm will be really useful when we start providing remote editing. Then a file is identifyed by its URI ( ftp://machine/path/to/file or scp://machine/path/to/file )

my @types = qw(initial, autosave, usersave, external);

sub save_data { my ($path, $timestamp, $type, $data) = @_; }