Function svn_prop_diffs 

pub unsafe extern "C" fn svn_prop_diffs(
    propdiffs: *mut *mut apr_array_header_t,
    target_props: *const apr_hash_t,
    source_props: *const apr_hash_t,
    pool: *mut apr_pool_t,
) -> *mut svn_error_t

Given two property hashes (const char *name -> const svn_string_t *value), deduce the differences between them (from @a source_props -> @c target_props). Set @a propdiffs to a new array of @c svn_prop_t structures, with one entry for each property that differs, including properties that exist in @a source_props or @a target_props but not both. The @c value field of each entry is that property’s value from @a target_props or NULL if that property only exists in @a source_props.

Allocate the array from @a pool. Allocate the contents of the array from @a pool or by reference to the storage of the input hashes or both.

For note, here’s a quick little table describing the logic of this routine:

@verbatim source_props target_props event

---

value = foo value = NULL Deletion occurred. value = foo value = bar Set occurred (modification) value = NULL value = baz Set occurred (creation) @endverbatim