Jonathan Nieder wrote on Fri, 25 Jun 2010 at 03:14 -0000: > Ramkumar Ramachandra wrote: > > > In future, it will dump the data in every revision > > to stdout in dumpfile format (hopefully) without resorting to the FS > > API. > > For now, just some naïve questions. Warning: I know nothing about > svn internals. > > I assume this corresponds to the ra-svn branch of > <http://github.com/artagnon/svn-dump-fast-export.git>. Has the > relevant code changed much since you sent it? > > > --- /dev/null > > +++ b/debug_editor.c > > @@ -0,0 +1,413 @@ > > +#include "svn_pools.h" > > +#include "svn_cmdline.h" > > +#include "svn_client.h" > > +#include "svn_ra.h" > > + > > +struct edit_baton > > What is a baton? > The context object for a callback. You call: some_function(your_callback_function, your_baton) which then calls: your_callback_function(your_baton, other_arguments) > [...] > > + void *wrapped_edit_baton; > [...] > > + void *edit_baton; > > + void *wrapped_dir_baton; > [...] > > + void *edit_baton; > > + void *wrapped_file_baton; > > Are these opaque types necessary? > The convention in Subversion's code is to convert the void * to a concrete_baton_t * only inside the callback. If you wish to declare these, e.g., as debug_editor_baton_t *wrapped_baton; You can probably do that too. > > + > > +static svn_error_t * > > +write_indent(struct edit_baton *eb, apr_pool_t *pool) > > +{ > > + int i; > > + > > + for (i = 0; i < eb->indent_level; ++i) > > + SVN_ERR(svn_stream_printf(eb->out, pool, " ")); > > + > > + return SVN_NO_ERROR; > > +} > > What does this do? Is SVN_ERR for debugging? That's how we implement exception throwing in C. SVN_ERR means "if this returned a non-NULL svn_error_t *, then return that error to our caller". The other pattern does svn_error_t *err = svn_stream_printf(); and then inspects err and err->apr_err to decide whether to ignore the error or return it (possibly wrapped). > Where does the output go? > SVN_ERR does not print anything. It may return(), though. > > +static svn_error_t * > > +set_target_revision(void *edit_baton, > > + svn_revnum_t target_revision, > > + apr_pool_t *pool) > [...] > > +static svn_error_t * > > +open_root(void *edit_baton, > [...] > > +static svn_error_t * > > +close_edit(void *edit_baton, > [...] > > I take it these are callbacks? Is there overview documentation for > them somewhere? > svn_delta_editor_t in http://svn.apache.org/repos/asf/subversion/trunk/subversion/include/svn_delta.h > > +svn_error_t * > > +svn_delta__get_debug_editor(const svn_delta_editor_t **editor, > > + void **edit_baton, > > + const svn_delta_editor_t *wrapped_editor, > > + void *wrapped_edit_baton, > > + apr_pool_t *pool) > > +{ > > + svn_delta_editor_t *tree_editor = svn_delta_default_editor(pool); > > + struct edit_baton *eb = apr_palloc(pool, sizeof(*eb)); > > + apr_file_t *errfp; > > + svn_stream_t *out; > > + > > + apr_status_t apr_err = apr_file_open_stderr(&errfp, pool); > > + if (apr_err) > > + return svn_error_wrap_apr(apr_err, "Problem opening stderr"); > > + > > + out = svn_stream_from_aprfile2(errfp, TRUE, pool); > > + > > + tree_editor->set_target_revision = set_target_revision; > > + tree_editor->open_root = open_root; > > + tree_editor->delete_entry = delete_entry; > > + tree_editor->add_directory = add_directory; > > + tree_editor->open_directory = open_directory; > > + tree_editor->change_dir_prop = change_dir_prop; > > + tree_editor->close_directory = close_directory; > > + tree_editor->absent_directory = absent_directory; > > + tree_editor->add_file = add_file; > > + tree_editor->open_file = open_file; > > + tree_editor->apply_textdelta = apply_textdelta; > > + tree_editor->change_file_prop = change_file_prop; > > + tree_editor->close_file = close_file; > > + tree_editor->absent_file = absent_file; > > + tree_editor->close_edit = close_edit; > > I take it that the fields of svn_delta_editor_t do not have a > well-defined order? Ugh. > I don't understand. It seems that the fields here appear in the same order as in the definition of struct svn_delta_editor_t. > In any case, I suspect this would be easier to read rearranged a little: > > 1. declarations for callbacks > 2. get_debug_editor implementation > 3. definitions of types not needed in get_debug_editor() > 4. implementations of callbacks > > That way, a person reading straight through can figure out what’s > going on a little earlier. > > > --- /dev/null > > +++ b/svnclient_ra.c > [...] > > +int main() > > +{ > > + const char url[] = "http://svn.apache.org/repos/asf";; > > + svn_revnum_t start_revision = 1, end_revision = 5; > > + if (svn_cmdline_init ("svnclient_ra", stderr) != EXIT_SUCCESS) > > + return 1; > > + pool = svn_pool_create(NULL); > > + > > + SVN_INT_ERR(open_connection(url)); > > + SVN_INT_ERR(replay_range(start_revision, end_revision)); > > + > > + close_connection(); > > + return 0; > > +} > > What is svn_cmdline_init? A Subversion API that does some necessary initializations (e.g., calls apr_initialize()). See subversion/include/svn_cmdline.h for docs (and subversion/libsvn_subr/cmdline.c for the implementation). > Is this code destined for inclusion in svn upstream, and if so, where > can one find the surrounding code this should fit in with? > > Jonathan >