diff mercurial/cext/revlog.c @ 44502:166349510398

revlog: using two new functions in C capsule from Rust code

We expose `index_length` and `index_node` in the C capsule, so that
the Rust representation of the C index can implement the `RevlogIndex`
trait.

Because our `Node` is actually a one-field struct, we have
to decorate it for direct FFI exchange with the C `char*`

It would be a good thing to get a length from the C layer, but doing
so right now would probably interfere with the upcoming changes that
will happen there for the hash length.

Differential Revision: https://phab.mercurial-scm.org/D8152

--- a/mercurial/cext/revlog.c	Tue Feb 18 19:11:14 2020 +0100
+++ b/mercurial/cext/revlog.c	Mon Jan 13 19:31:33 2020 +0100
@@ -39,6 +39,8 @@
 
 typedef struct {
 	int abi_version;
+	Py_ssize_t (*index_length)(const indexObject *);
+	const char *(*index_node)(indexObject *, Py_ssize_t);
 	int (*index_parents)(PyObject *, int, int *);
 } Revlog_CAPI;
 
@@ -2877,7 +2879,9 @@
 static Revlog_CAPI CAPI = {
     /* increment the abi_version field upon each change in the Revlog_CAPI
        struct or in the ABI of the listed functions */
-    1,
+    2,
+    index_length,
+    index_node,
     HgRevlogIndex_GetParents,
 };