Seems fine, and there should be no affect on the API/ABI. And thanks
for not including the '*' in there... that was a very poor choice for
the mergeinfo :-(
On Fri, Jul 27, 2012 at 3:24 PM, Julian Foad <julianfoad_at_btopenworld.com> wrote:
> Actually, it'll be called "svn_rangelist_t", since we've already got lots of public "svn_rangelist_...()" functions.
>
> - Julian
>
>
>
>
> ----- Original Message -----
>> From: Julian Foad <julianfoad_at_btopenworld.com>
>> To: Subversion Development <dev_at_subversion.apache.org>
>> Cc:
>> Sent: Friday, 27 July 2012, 10:36
>> Subject: Heads-up: new typedef 'svn_merge_rangelist_t'
>>
>> Heads up: I'm going to add
>>
>> typedef apr_array_header_t svn_merge_rangelist_t;
>>
>> There's no major impact; it doesn't change anything functionally.
>>
>> The rest of the details:
>> The immediate reason is to improve the debugging experience: I can then make GDB
>> display 'rangelist' values in a simple human-readable form, whereas
>> presently the best it can do is recognize that it is an APR array and display
>> something like "array of 2 items".
>>
>> Beyond that, it makes sense from a coding abstraction point of view: it fills in
>> the gap in this hierarchy of types (quoting from svn_mergeinfo.h):
>>
>> /** Terminology for data structures that contain mergeinfo.
>> *
>> * Subversion commonly uses several data structures to represent
>> * mergeinfo in RAM:
>> *
>> * (a) Strings (@c svn_string_t *) containing "unparsed mergeinfo".
>> *
>> * (b) A "rangelist". An array (@c apr_array_header_t *) of
>> non-overlapping
>> * merge ranges (@c svn_merge_range_t *), sorted as said by
>> * @c svn_sort_compare_ranges(). An empty range list is [...].
>> *
>> * (c) @c svn_mergeinfo_t, called "mergeinfo". A hash mapping merge
>> * source paths (@c const char *, starting with slashes) to
>> * non-empty rangelist arrays. A @c NULL hash is used to [...].
>> *
>> * (d) @c svn_mergeinfo_catalog_t, called a "mergeinfo catalog". A
>> hash
>> * mapping paths (@c const char *) to @c svn_mergeinfo_t.
>> *
>> * Both @c svn_mergeinfo_t and @c svn_mergeinfo_catalog_t are just
>> * typedefs for @c apr_hash_t *; there is no static type-checking, and
>> * you still use standard @c apr_hash_t functions to interact with
>> * them. [...]
>> */
>>
>> typedef apr_hash_t *svn_mergeinfo_t;
>> typedef apr_hash_t *svn_mergeinfo_catalog_t;
>>
>> The new type will be public. Because it's just a typedef, the C API will be
>> backward-compatible and it won't change the ABI. (Can someone confirm
>> that?)
>>
>> As mentioned in that doc string, using such a typedef doesn't provide any
>> static type-checking.
>>
>> svn_merge_rangelist_t is not going to be a pointer like svn_mergeinfo_t and
>> svn_mergeinfo_catalog_t are, since that is a poor idiom leading to inability to
>> declare a parameter as "pointer to a const rangelist".
>>
>> - Julian
>>
Received on 2012-07-27 23:08:45 CEST