Re: CVS update: subversion/subversion/include svn_delta.h

[Greg Stein <gs...@lyra.org>]

On Wed, Feb 28, 2001 at 11:06:19PM -0000, sussman@tigris.org wrote:
>...
>    /* Set *STREAM to a pointer to a delta stream that will turn an empty
>   -   bytestream into STRING. */
>   +   bytestream into STRING.  Do necessary allocation in POOL.
>   +
>   +   When we call `svn_txdelta_next_window' on *STREAM, the window
>   +   returned will contain pointers directly into STRING (rather than
>   +   duplicating STRING's data.)  So callers beware:  make sure STRING
>   +   is not freed before STREAM and its windows!   */
>    void svn_txdelta_from_string (svn_txdelta_stream_t **stream,
>                                  svn_string_t *string,
>                                  apr_pool_t *pool);

That first sentence doesn't make sense. What does "empty bytestream" have to
do with anything? And we aren't putting anything "into" STRING, are we?

It seems more like this is a way to *read* a txdelta stream *from* a string,
right?

Cheers,
-g

-- 
Greg Stein, http://www.lyra.org/

Re: CVS update: subversion/subversion/include svn_delta.h

[Jim Blandy <ji...@zwingli.cygnus.com>]

Ben Collins-Sussman <su...@newton.ch.collab.net> writes:
> The stream produces a series of windows which converts some "source"
> bytestring into a "target" bytestring, right?  The "target" we want
> the consumer to construct is STRING.  So what's the "source" in this
> case?  If the windows are full of nothing but `new' ops, then the
> source is nothing.  We're telling the consumer how to construct STRING
> from nothingness.
> 
> Isn't this a consistent analogy?

It makes sense to me, with one correction: the text delta you're
constructing will turn *any* source string into the given target
string.  The source string needn't be empty.

Re: CVS update: subversion/subversion/include svn_delta.h

[Ben Collins-Sussman <su...@newton.ch.collab.net>]

Greg Stein <gs...@lyra.org> writes:

> On Wed, Feb 28, 2001 at 11:06:19PM -0000, sussman@tigris.org wrote:
> >...
> >    /* Set *STREAM to a pointer to a delta stream that will turn an empty
> >   -   bytestream into STRING. */
> >   +   bytestream into STRING.  Do necessary allocation in POOL.
> >   +
> >   +   When we call `svn_txdelta_next_window' on *STREAM, the window
> >   +   returned will contain pointers directly into STRING (rather than
> >   +   duplicating STRING's data.)  So callers beware:  make sure STRING
> >   +   is not freed before STREAM and its windows!   */
> >    void svn_txdelta_from_string (svn_txdelta_stream_t **stream,
> >                                  svn_string_t *string,
> >                                  apr_pool_t *pool);
> 
> That first sentence doesn't make sense. What does "empty bytestream" have to
> do with anything? And we aren't putting anything "into" STRING, are we?
> 
> It seems more like this is a way to *read* a txdelta stream *from* a string,
> right?

Right.

I'm just trying to stick to the definition of a "txdelta_stream",
copying from the declaration above it.

The stream produces a series of windows which converts some "source"
bytestring into a "target" bytestring, right?  The "target" we want
the consumer to construct is STRING.  So what's the "source" in this
case?  If the windows are full of nothing but `new' ops, then the
source is nothing.  We're telling the consumer how to construct STRING
from nothingness.

Isn't this a consistent analogy?