[Scummvm-devel] File handling revamp

[peres]

Here are my laughable 2 cents (especially laughable since I got up to
write after I had gone to sleep).

>>
>> The code suffers from case sensitivty issues on Linux for example. A  
>> user
>> with the files in uppercase would of course get some file not found  
>> error
>> messages.
>
> OK. So, we should change FSNodes to be case insensitive. Noted!

I don't think changing FSNodes to be case insensitive is a good idea,
since it is the foundation on which File, DumpFile, ConfigFile and
SaveFile are built. We have the following situation:

* File: created by a software house, located and read by ScummVM
* ConfigFile: created by the user (also by ScummVM, but user can change
it), located and read by ScummVM
* DumpFile: created by a developer (via ScummVM), located and read by a
developer
* SaveFile: created by an engine, located and read by an engine (the same
engine!)

SaveFile is not interesting since the engine manages all its existence
(provided the user doesn't mess with it!), but the remaining 3
incarnations all show the same pattern, that is the creator of the file is
not the same as its user.

DumpFile is a tool for developers, and it is slightly more interesting.
Personally, I want my tools to follow my instructions, and I would be very
annoyed if I couldn't dump 'core', 'Core', 'CORE' in the same directory,
or worse, to have one overwrite the others. Anyway, it is debatable.

ConfigFile is more delicate, since it may be created (and modified) by any
user. We shouldn't get in their way of handling their own file systems,
because they must be able to choose what it's best for them. I understand
keeping multiple file systems in directories called 'myconf', "myConf' and
'Myconf' is madness, but after all it would be worse to create problems to
them.

There should be little issues so far, in fact it's the way things are
managed in ScummVM right now (maybe not for DumpFile, but it's not so
fundamental).

Our File is the bad guy! I will call it GameFile from now on, as it seems
a more focused and proper name. After all, since DumpFile has been
created, we are *only* going to use it to read game data, right? GameFile
would be a thin layer over FSNode, with the responsibility of handling
case, and it would have a companion called GameDirectory, to aid keeping
filish and directorish stuff separated.
The root GameDirectory would be returned by a method in OSystem (there
were plans for getting/setting ConfigFile as well, no?), and then the
engine would be able to tell it wants it to be case sensitive or not
(because the engine *knows*). Since every other GameDirectory and GameFile
would originate from the root, the case [in]sensitiveness can be easily
propagated.
In case of a name clash when looking up a GameFile, I dare to say the only
sensible solution is to explicitly tell the user to fix his/her messy
directory and error out!


I hope there is something worthy in the middle of all this stuff I wrote
at 3.13 am.

bye
Nicola