[Gnash-dev] Curl adapter status

[strk]

I've have a libcurl adapter for tu_file working.
It uses a temporary file as a buffer, so it will
be easy to add persistent caching later.

Currently the adapter expects a *real* url, not
a local filename, so the check to decide wheter
the requested url belongs to a local filename
or to a network resource must be implemented
in the caller. I think this makes sense as
a caller should now about it anyway, to decide
caching strategies.
We'd probably need a generic class for grabbing
data, maintainin a map of <url> to <stream>.
The default instance should take care of using
what's available for different kind of access
methods.

So, for now I just committed the curl_adapter.{cpp,h}
files.  No changed to Makefiles yet. Will next work
on the macro for libcurl detection.

After that, we should decide how to proceed.
I conducted my tests by setting the file_opener
callback in backend/gnash.cpp (basically
hooking on the backend/gnash.cpp file_opener
static function), but I'm not sure this is
the way to go, as we'd be using #ifdef blocks
all over the place to decide wheter or not
to use the curl adapter, plus we should still
verify that the requested <url> is not local.

Suggestions welcome.

--strk;

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