[email protected] wrote on Wed, Jul 24, 2013 at 14:32:48 -0000:
> Author: stefan2
> Date: Wed Jul 24 14:32:48 2013
> New Revision: 1506576
> 
> URL: http://svn.apache.org/r1506576
> Log:
> On the fsfs-improvements branch:  With the new ID types in place,
> we can now replace other string with a struct
> 
> +     intra-node uniqification content. */
> +  struct
> +    {
> +      svn_fs_fs__id_part_t txn_id;

I'd rename this inner-struct member to avoid confusion with the
eponymous member of the outer struct.

As to the rest... I don't grok yet the new stuff.  Looks like there is
an entirely new ID API, which was just thrown in with little docs as to
the intended end-result or difference from the current one :-(

What is the difference between svn_fs_fs__id_txn_id()
and svn_fs_fs__id_is_txn()?  Why can't one of them be deleted?

svn_fs_fs__id_is_txn() uses svn_fs_fs__id_txn_used().  I haven't looked
at callers, but wouldn't it be a coding error (i.e., an assert()-level
bug) to have an fs_fs__id_t struct which has not been initialized to be
either a revid or a txnid?  Or do we have now a trimodal object
[uninit'd, txnid, revid]?  (If the latter, I would wonder how many
places in the code we have that assume a bimodal [txnid, revid]
model...)

Why does svn_fs_fs__id_is_txn() use a struct-extension instead of
svn_fs_id_t.fsap_data?  Is that just in order to have svn_fs_id_t
struct and the FSFS-private part of it be allocated contiguously?

Why is svn_fs_fs__id_offset() not reimplemented as
    #define svn_fs_fs__id_offset(id) svn_fs_fs__id_rev_offset(id).number
?  i.e., why are both accessors needed?

Does the transition from 'const char *' to svn_fs_fs__id_part_t require
changes to 'structure'?  The signature of svn_fs_fs__id_txn_create()
implies that a "noderev id" is now a three-tuple of three (revnum,
offset) pairs.  That doesn't match 'structure'.

What is "rev node ID" in the docstring of svn_fs_fs__id_part_t?  Should
it read "the txn-id component of a noderev-id"?

Bottom line: I don't know that I understand this.  The duplication of
svn_fs_fs__id_is_txn() svn_fs_fs__id_txn_used() makes me wary of NIH,
and the other changes makes me worry if the all-too-common tendency to
change the format without updating 'structure' has striken again.

(Incidentally, trunk/subversion/libsvn_fs_x/structure is wrong --- it
describes FSFS f6, not FSX.)

Cheers,

Daniel

> +      apr_uint64_t number;
> +    } uniquifier;
>  } representation_t;

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