[PATCH v2] reftable: use a pointer for pq_entry param

[Elijah Conners <business@xxxxxxxxxxxxxx>]

The speed of the merged_iter_pqueue_add() can be improved by using a
pointer to the pq_entry struct, which is 96 bytes. Since the pq_entry
param is worked directly on the stack and does not currently have a
pointer to it, the merged_iter_pqueue_add() function is slightly
slower.

References to pq_entry in reftable have typically included pointers,
such as both of the params for pq_less().

Since we are working with pointers in the pq_entry param, as keenly
pointed out, the pq_entry param has also been made into a const since
the contents of the pq_entry param are copied and not manipulated.

Signed-off-by: Elijah Conners <business@xxxxxxxxxxxxxx>
---
 reftable/merged.c  | 4 ++--
 reftable/pq.c      | 4 ++--
 reftable/pq.h      | 2 +-
 reftable/pq_test.c | 2 +-
 4 files changed, 6 insertions(+), 6 deletions(-)

diff --git a/reftable/merged.c b/reftable/merged.c
index 2a6efa110d..5ded470c08 100644
--- a/reftable/merged.c
+++ b/reftable/merged.c
@@ -36,7 +36,7 @@ static int merged_iter_init(struct merged_iter *mi)
                                .rec = rec,
                                .index = i,
                        };
-                       merged_iter_pqueue_add(&mi->pq, e);
+                       merged_iter_pqueue_add(&mi->pq, &e);
                }
        }

@@ -71,7 +71,7 @@ static int merged_iter_advance_nonnull_subiter(struct merged_iter *mi,
                return 0;
        }

-       merged_iter_pqueue_add(&mi->pq, e);
+       merged_iter_pqueue_add(&mi->pq, &e);
        return 0;
 }

diff --git a/reftable/pq.c b/reftable/pq.c
index 96ca6dd37b..dcefeb793a 100644
--- a/reftable/pq.c
+++ b/reftable/pq.c
@@ -71,7 +71,7 @@ struct pq_entry merged_iter_pqueue_remove(struct merged_iter_pqueue *pq)
        return e;
 }

-void merged_iter_pqueue_add(struct merged_iter_pqueue *pq, struct pq_entry e)
+void merged_iter_pqueue_add(struct merged_iter_pqueue *pq, const struct pq_entry *e)
 {
        int i = 0;

@@ -81,7 +81,7 @@ void merged_iter_pqueue_add(struct merged_iter_pqueue *pq, struct pq_entry e)
                                            pq->cap * sizeof(struct pq_entry));
        }

-       pq->heap[pq->len++] = e;
+       pq->heap[pq->len++] = *e;
        i = pq->len - 1;
        while (i > 0) {
                int j = (i - 1) / 2;
diff --git a/reftable/pq.h b/reftable/pq.h
index 56fc1b6d87..e85bac9b52 100644
--- a/reftable/pq.h
+++ b/reftable/pq.h
@@ -26,7 +26,7 @@ struct pq_entry merged_iter_pqueue_top(struct merged_iter_pqueue pq);
 int merged_iter_pqueue_is_empty(struct merged_iter_pqueue pq);
 void merged_iter_pqueue_check(struct merged_iter_pqueue pq);
 struct pq_entry merged_iter_pqueue_remove(struct merged_iter_pqueue *pq);
-void merged_iter_pqueue_add(struct merged_iter_pqueue *pq, struct pq_entry e);
+void merged_iter_pqueue_add(struct merged_iter_pqueue *pq, const struct pq_entry *e);
 void merged_iter_pqueue_release(struct merged_iter_pqueue *pq);
 int pq_less(struct pq_entry *a, struct pq_entry *b);

diff --git a/reftable/pq_test.c b/reftable/pq_test.c
index 7de5e886f3..011b5c7502 100644
--- a/reftable/pq_test.c
+++ b/reftable/pq_test.c
@@ -46,7 +46,7 @@ static void test_pq(void)
                                               .u.ref = {
                                                       .refname = names[i],
                                               } } };
-               merged_iter_pqueue_add(&pq, e);
+               merged_iter_pqueue_add(&pq, &e);
                merged_iter_pqueue_check(pq);
                i = (i * 7) % N;
        } while (i != 1);
--
2.29.2.windows.2