oid_pos(): access table through const pointers

peff · gitster · commit 8380dcd700e8 · 2021-01-28T12:03:26.000-08:00
When we are looking up an oid in an array, we obviously don't need to
write to the array. Let's mark it as const in the function interfaces,
as well as in the local variables we use to derference the void pointer
(note a few cases use pointers-to-pointers, so we mark everything
const).

Signed-off-by: Jeff King &lt;peff@peff.net&gt;
Signed-off-by: Junio C Hamano &lt;gitster@pobox.com&gt;
diff --git a/builtin/name-rev.c b/builtin/name-rev.c
@@ -390,9 +390,9 @@ static void name_tips(void)
 	}
 }
 
-static const struct object_id *nth_tip_table_ent(size_t ix, void *table_)
+static const struct object_id *nth_tip_table_ent(size_t ix, const void *table_)
 {
-	struct tip_table_entry *table = table_;
+	const struct tip_table_entry *table = table_;
 	return &table[ix].oid;
 }
 
diff --git a/commit-graph.c b/commit-graph.c
@@ -1012,9 +1012,9 @@ static int write_graph_chunk_oids(struct hashfile *f,
 	return 0;
 }
 
-static const struct object_id *commit_to_oid(size_t index, void *table)
+static const struct object_id *commit_to_oid(size_t index, const void *table)
 {
-	struct commit **commits = table;
+	const struct commit * const *commits = table;
 	return &commits[index]->object.oid;
 }
 
diff --git a/commit.c b/commit.c
@@ -105,9 +105,9 @@ static timestamp_t parse_commit_date(const char *buf, const char *tail)
 	return parse_timestamp(dateptr, NULL, 10);
 }
 
-static const struct object_id *commit_graft_oid_access(size_t index, void *table)
+static const struct object_id *commit_graft_oid_access(size_t index, const void *table)
 {
-	struct commit_graft **commit_graft_table = table;
+	const struct commit_graft * const *commit_graft_table = table;
 	return &commit_graft_table[index]->oid;
 }
 
diff --git a/hash-lookup.c b/hash-lookup.c
@@ -50,7 +50,7 @@ static uint32_t take2(const struct object_id *oid, size_t ofs)
  * The oid of element i (between 0 and nr - 1) should be returned
  * by "fn(i, table)".
  */
-int oid_pos(const struct object_id *oid, void *table, size_t nr,
+int oid_pos(const struct object_id *oid, const void *table, size_t nr,
 	    oid_access_fn fn)
 {
 	size_t hi = nr;
diff --git a/hash-lookup.h b/hash-lookup.h
@@ -1,10 +1,10 @@
 #ifndef HASH_LOOKUP_H
 #define HASH_LOOKUP_H
 
-typedef const struct object_id *oid_access_fn(size_t index, void *table);
+typedef const struct object_id *oid_access_fn(size_t index, const void *table);
 
 int oid_pos(const struct object_id *oid,
-	    void *table,
+	    const void *table,
 	    size_t nr,
 	    oid_access_fn fn);
 
diff --git a/oid-array.c b/oid-array.c
@@ -22,9 +22,9 @@ void oid_array_sort(struct oid_array *array)
 	array->sorted = 1;
 }
 
-static const struct object_id *oid_access(size_t index, void *table)
+static const struct object_id *oid_access(size_t index, const void *table)
 {
-	struct object_id *array = table;
+	const struct object_id *array = table;
 	return &array[index];
 }
 
diff --git a/pack-bitmap-write.c b/pack-bitmap-write.c
@@ -610,9 +610,9 @@ static inline void dump_bitmap(struct hashfile *f, struct ewah_bitmap *bitmap)
 		die("Failed to write bitmap index");
 }
 
-static const struct object_id *oid_access(size_t pos, void *table)
+static const struct object_id *oid_access(size_t pos, const void *table)
 {
-	struct pack_idx_entry **index = table;
+	const struct pack_idx_entry * const *index = table;
 	return &index[pos]->oid;
 }
 

Original file line number	Diff line number	Diff line change
`@@ -390,9 +390,9 @@ static void name_tips(void)`
`390`	`390`	`}`
`391`	`391`	`}`
`392`	`392`
`393`		`-static const struct object_id nth_tip_table_ent(size_t ix, void table_)`
	`393`	`+static const struct object_id nth_tip_table_ent(size_t ix, const void table_)`
`394`	`394`	`{`
`395`		`- struct tip_table_entry *table = table_;`
	`395`	`+ const struct tip_table_entry *table = table_;`
`396`	`396`	`return &table[ix].oid;`
`397`	`397`	`}`
`398`	`398`
Original file line number	Diff line number	Diff line change
`@@ -1012,9 +1012,9 @@ static int write_graph_chunk_oids(struct hashfile *f,`
`1012`	`1012`	`return 0;`
`1013`	`1013`	`}`
`1014`	`1014`
`1015`		`-static const struct object_id commit_to_oid(size_t index, void table)`
	`1015`	`+static const struct object_id commit_to_oid(size_t index, const void table)`
`1016`	`1016`	`{`
`1017`		`- struct commit **commits = table;`
	`1017`	`+ const struct commit * const *commits = table;`
`1018`	`1018`	`return &commits[index]->object.oid;`
`1019`	`1019`	`}`
`1020`	`1020`
Original file line number	Diff line number	Diff line change
`@@ -105,9 +105,9 @@ static timestamp_t parse_commit_date(const char buf, const char tail)`
`105`	`105`	`return parse_timestamp(dateptr, NULL, 10);`
`106`	`106`	`}`
`107`	`107`
`108`		`-static const struct object_id commit_graft_oid_access(size_t index, void table)`
	`108`	`+static const struct object_id commit_graft_oid_access(size_t index, const void table)`
`109`	`109`	`{`
`110`		`- struct commit_graft **commit_graft_table = table;`
	`110`	`+ const struct commit_graft * const *commit_graft_table = table;`
`111`	`111`	`return &commit_graft_table[index]->oid;`
`112`	`112`	`}`
`113`	`113`
Original file line number	Diff line number	Diff line change
`@@ -50,7 +50,7 @@ static uint32_t take2(const struct object_id *oid, size_t ofs)`
`50`	`50`	`* The oid of element i (between 0 and nr - 1) should be returned`
`51`	`51`	`* by "fn(i, table)".`
`52`	`52`	`*/`
`53`		`-int oid_pos(const struct object_id oid, void table, size_t nr,`
	`53`	`+int oid_pos(const struct object_id oid, const void table, size_t nr,`
`54`	`54`	`oid_access_fn fn)`
`55`	`55`	`{`
`56`	`56`	`size_t hi = nr;`
Original file line number	Diff line number	Diff line change
`@@ -22,9 +22,9 @@ void oid_array_sort(struct oid_array *array)`
`22`	`22`	`array->sorted = 1;`
`23`	`23`	`}`
`24`	`24`
`25`		`-static const struct object_id oid_access(size_t index, void table)`
	`25`	`+static const struct object_id oid_access(size_t index, const void table)`
`26`	`26`	`{`
`27`		`- struct object_id *array = table;`
	`27`	`+ const struct object_id *array = table;`
`28`	`28`	`return &array[index];`
`29`	`29`	`}`
`30`	`30`
Original file line number	Diff line number	Diff line change
`@@ -610,9 +610,9 @@ static inline void dump_bitmap(struct hashfile f, struct ewah_bitmap bitmap)`
`610`	`610`	`die("Failed to write bitmap index");`
`611`	`611`	`}`
`612`	`612`
`613`		`-static const struct object_id oid_access(size_t pos, void table)`
	`613`	`+static const struct object_id oid_access(size_t pos, const void table)`
`614`	`614`	`{`
`615`		`- struct pack_idx_entry **index = table;`
	`615`	`+ const struct pack_idx_entry * const *index = table;`
`616`	`616`	`return &index[pos]->oid;`
`617`	`617`	`}`
`618`	`618`