[PATCH 5 of 6] rust: look up HgRevlogIndex_GetParents() from symbol table

[Georges Racinet]

On 12/5/18 2:43 PM, Yuya Nishihara wrote:
> # HG changeset patch
> # User Yuya Nishihara <yuya at tcha.org>
> # Date 1543756838 -32400
> #      Sun Dec 02 22:20:38 2018 +0900
> # Node ID f5cdfa49994e3943ba7c4ce2d66708142f0c7058
> # Parent  716a73bab79be30c20c75e13324c44205d5e2120
> rust: look up HgRevlogIndex_GetParents() from symbol table
>
> And removes the unused index_get_parents_checked() function.
>
> I expect the Index struct will be turned into a pyobject type, though I
> haven't written any PoC-level patches yet.

I'm not sure what you mean exactly with turning Index into a pyobject
type. Would you care to elaborate ?

No question about the rest of the patch.

>
> diff --git a/mercurial/cext/revlog.c b/mercurial/cext/revlog.c
> --- a/mercurial/cext/revlog.c
> +++ b/mercurial/cext/revlog.c
> @@ -2710,27 +2710,15 @@ struct rustlazyancestorsObjectStruct {
>  };
>  
>  /* FFI exposed from Rust code */
> -rustlazyancestorsObject *
> -rustlazyancestors_init(indexObject *index,
> -                       /* to pass index_get_parents() */
> -                       int (*)(indexObject *, Py_ssize_t, int *, int),
> -                       /* intrevs vector */
> -                       Py_ssize_t initrevslen, long *initrevs, long stoprev,
> -                       int inclusive);
> +rustlazyancestorsObject *rustlazyancestors_init(indexObject *index,
> +                                                /* intrevs vector */
> +                                                Py_ssize_t initrevslen,
> +                                                long *initrevs, long stoprev,
> +                                                int inclusive);
>  void rustlazyancestors_drop(rustlazyancestorsObject *self);
>  int rustlazyancestors_next(rustlazyancestorsObject *self);
>  int rustlazyancestors_contains(rustlazyancestorsObject *self, long rev);
>  
> -static int index_get_parents_checked(indexObject *self, Py_ssize_t rev, int *ps,
> -                                     int maxrev)
> -{
> -	if (rev < 0 || rev >= index_length(self)) {
> -		PyErr_SetString(PyExc_ValueError, "rev out of range");
> -		return -1;
> -	}
> -	return index_get_parents(self, rev, ps, maxrev);
> -}
> -
>  /* CPython instance methods */
>  static int rustla_init(rustlazyancestorsObject *self, PyObject *args)
>  {
> @@ -2768,12 +2756,12 @@ static int rustla_init(rustlazyancestors
>  	if (PyErr_Occurred())
>  		goto bail;
>  
> -	self->iter = rustlazyancestors_init(index, index_get_parents, linit,
> -	                                    initrevs, stoprev, inclusive);
> +	self->iter =
> +	    rustlazyancestors_init(index, linit, initrevs, stoprev, inclusive);
>  	if (self->iter == NULL) {
>  		/* if this is because of GraphError::ParentOutOfRange
> -		 * index_get_parents_checked() has already set the proper
> -		 * ValueError */
> +		 * HgRevlogIndex_GetParents() has already set the proper
> +		 * exception */
>  		goto bail;
>  	}
>  
> diff --git a/rust/hg-direct-ffi/src/ancestors.rs b/rust/hg-direct-ffi/src/ancestors.rs
> --- a/rust/hg-direct-ffi/src/ancestors.rs
> +++ b/rust/hg-direct-ffi/src/ancestors.rs
> @@ -16,9 +16,14 @@ use std::ptr::null_mut;
>  use std::slice;
>  
>  type IndexPtr = *mut c_void;
> -type IndexParentsFn =
> -    unsafe extern "C" fn(index: IndexPtr, rev: ssize_t, ps: *mut [c_int; 2], max_rev: c_int)
> -        -> c_int;
> +
> +extern "C" {
> +    fn HgRevlogIndex_GetParents(
> +        op: IndexPtr,
> +        rev: c_int,
> +        parents: *mut [c_int; 2],
> +    ) -> c_int;
> +}
>  
>  /// A Graph backed up by objects and functions from revlog.c
>  ///
> @@ -27,14 +32,12 @@ type IndexParentsFn =
>  /// - the `index_get_parents()` function (`parents` member)
>  pub struct Index {
>      index: IndexPtr,
> -    parents: IndexParentsFn,
>  }
>  
>  impl Index {
> -    pub fn new(index: IndexPtr, parents: IndexParentsFn) -> Self {
> +    pub fn new(index: IndexPtr) -> Self {
>          Index {
>              index: index,
> -            parents: parents,
>          }
>      }
>  }
> @@ -44,7 +47,7 @@ impl Graph for Index {
>      fn parents(&self, rev: Revision) -> Result<(Revision, Revision), GraphError> {
>          let mut res: [c_int; 2] = [0; 2];
>          let code =
> -            unsafe { (self.parents)(self.index, rev as ssize_t, &mut res as *mut [c_int; 2], rev) };
> +            unsafe { HgRevlogIndex_GetParents(self.index, rev, &mut res as *mut [c_int; 2]) };
>          match code {
>              0 => Ok((res[0], res[1])),
>              _ => Err(GraphError::ParentOutOfRange(rev)),
> @@ -59,7 +62,6 @@ impl Graph for Index {
>  #[no_mangle]
>  pub extern "C" fn rustlazyancestors_init(
>      index: IndexPtr,
> -    parents: IndexParentsFn,
>      initrevslen: ssize_t,
>      initrevs: *mut c_long,
>      stoprev: c_long,
> @@ -68,7 +70,7 @@ pub extern "C" fn rustlazyancestors_init
>      assert!(initrevslen >= 0);
>      unsafe {
>          raw_init(
> -            Index::new(index, parents),
> +            Index::new(index),
>              initrevslen as usize,
>              initrevs,
>              stoprev,
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-- 
Georges Racinet
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