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Re: two questions in the SVN source code

From: Bo Chen <bo.irvine.chen_at_gmail.com>
Date: Sat, 6 Apr 2013 14:33:31 -0400

Basically, what I want to do here is to retrieve a certain file from any
two revisions (directly from the repository), and compute the delta between
these two file versions. So I need to know first how can I retrieve a
certain file from any revision of the repository (what functions I can use
in the current code base? etc.), and how to compute the delta (I may
directly use the functions in \libsvn_delta\txdelta.c). Do you have any
suggestion for me?


On Sat, Apr 6, 2013 at 1:50 AM, Ben Reser <ben_at_reser.org> wrote:

> On Fri, Apr 5, 2013 at 10:02 PM, Bo Chen <bo.irvine.chen_at_gmail.com> wrote:
> > I need help for the following two questions. Any help will be
> appreciated.
> >
> > 1 Given a revision number, which function can (should be in
> libsvn_fs_fs/)
> > can read the corresponding revision from the repository (FSFS)?
> You really shouldn't be using libsvn_fs_fs directly and should use
> libsvn_repos and libsvn_fs. Beyond that I really don't know what you
> mean by "read the corresponding revision." There are all sorts of
> APIs for getting specific information about a revision. I don't think
> we have a function or a structure to represent an entire revision in
> memory. Generally you get a revision root by using
> svn_fs_revision_root() which gives you a svn_fs_root_t and then you
> use functions against it. You may find the source for svnlook
> particularly instructive since it provides implementations of a lot of
> the type of queries you might want to do. Say you want to find the
> nodes changes in a revision, the changed command does this and it does
> it by retrieving the revision root, determining the base revision and
> then using svn_repos_replay2() to build a svn_repos_node_t tree of the
> changed nodes.
> It might be helpful for you to tell us overall what you're doing and
> we might be able to point you in the right direction more quickly than
> answering these one off questions.
> > 2 For a variable of svn_stream_t, how can I print the information (e.g.,
> the
> > string) stored in this variable.
> If you want something quick and dirty for debugging without worrying
> about encoding you probably want to use
> svn_stream_for_stdout() or svn_stream_for_stderr() to get stdout or
> stderr as a stream and then use svn_stream_copy3().
> If you need something more permanent and care about the encoding I
> think you have to use the svn_cmdline_* functions, which don't take
> svn_stream_t's so you'll have to consume the stream with
> svn_stream_read() and then write the output with svn_cmdline_*.
Received on 2013-04-06 20:34:03 CEST

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