Move hash_any prototype from access/hash.h to utils/hashutils.h

... as well as its implementation from backend/access/hash/hashfunc.c to
backend/utils/hash/hashfn.c.

access/hash is the place for the hash index AM, not really appropriate
for generic facilities, which is what hash_any is; having things the old
way meant that anything using hash_any had to include the AM's include
file, pointlessly polluting its namespace with unrelated, unnecessary
cruft.

Also move the HTEqual strategy number to access/stratnum.h from
access/hash.h.

To avoid breaking third-party extension code, add an #include
"utils/hashutils.h" to access/hash.h.  (An easily removed line by
committers who enjoy their asbestos suits to protect them from angry
extension authors.)

Discussion: https://postgr.es/m/201901251935.ser5e4h6djt2@alvherre.pgsql

contrib/citext/citext.c

@@ -3,10 +3,10 @@
  */
 #include "postgres.h"
 
-#include "access/hash.h"
 #include "catalog/pg_collation.h"
 #include "utils/builtins.h"
 #include "utils/formatting.h"
+#include "utils/hashutils.h"
 #include "utils/varlena.h"
 
 PG_MODULE_MAGIC;

contrib/hstore/hstore_op.c

@@ -3,11 +3,11 @@
  */
 #include "postgres.h"
 
-#include "access/hash.h"
 #include "access/htup_details.h"
 #include "catalog/pg_type.h"
 #include "funcapi.h"
 #include "utils/builtins.h"
+#include "utils/hashutils.h"
 #include "utils/memutils.h"
 
 #include "hstore.h"

contrib/pg_stat_statements/pg_stat_statements.c

@@ -61,7 +61,6 @@
 #include <sys/stat.h>
 #include <unistd.h>
 
-#include "access/hash.h"
 #include "catalog/pg_authid.h"
 #include "executor/instrument.h"
 #include "funcapi.h"
@@ -78,6 +77,7 @@
 #include "tcop/utility.h"
 #include "utils/acl.h"
 #include "utils/builtins.h"
+#include "utils/hashutils.h"
 #include "utils/memutils.h"
 
 PG_MODULE_MAGIC;

contrib/sepgsql/uavc.c

@@ -12,11 +12,11 @@
  */
 #include "postgres.h"
 
-#include "access/hash.h"
 #include "catalog/pg_proc.h"
 #include "commands/seclabel.h"
 #include "storage/ipc.h"
 #include "utils/guc.h"
+#include "utils/hashutils.h"
 #include "utils/memutils.h"
 
 #include "sepgsql.h"

src/backend/access/common/tupdesc.c

@@ -19,7 +19,6 @@
 
 #include "postgres.h"
 
-#include "access/hash.h"
 #include "access/htup_details.h"
 #include "access/tupdesc_details.h"
 #include "catalog/pg_collation.h"

src/backend/access/tablesample/bernoulli.c

@@ -26,11 +26,11 @@
 
 #include <math.h>
 
-#include "access/hash.h"
 #include "access/tsmapi.h"
 #include "catalog/pg_type.h"
 #include "optimizer/optimizer.h"
 #include "utils/builtins.h"
+#include "utils/hashutils.h"
 
 
 /* Private state */

src/backend/access/tablesample/system.c

@@ -26,13 +26,13 @@
 
 #include <math.h>
 
-#include "access/hash.h"
 #include "access/heapam.h"
 #include "access/relscan.h"
 #include "access/tsmapi.h"
 #include "catalog/pg_type.h"
 #include "optimizer/optimizer.h"
 #include "utils/builtins.h"
+#include "utils/hashutils.h"
 
 
 /* Private state */

src/backend/catalog/pg_publication.c

@@ -18,7 +18,6 @@
 #include "miscadmin.h"
 
 #include "access/genam.h"
-#include "access/hash.h"
 #include "access/heapam.h"
 #include "access/htup_details.h"
 #include "access/xact.h"

src/backend/commands/publicationcmds.c

@@ -18,7 +18,6 @@
 #include "miscadmin.h"
 
 #include "access/genam.h"
-#include "access/hash.h"
 #include "access/htup_details.h"
 #include "access/table.h"
 #include "access/xact.h"

src/backend/executor/execGrouping.c

@@ -18,7 +18,6 @@
  */
 #include "postgres.h"
 
-#include "access/hash.h"
 #include "access/parallel.h"
 #include "executor/executor.h"
 #include "miscadmin.h"

src/backend/executor/nodeSamplescan.c

@@ -14,7 +14,6 @@
  */
 #include "postgres.h"
 
-#include "access/hash.h"
 #include "access/heapam.h"
 #include "access/relscan.h"
 #include "access/tsmapi.h"
@@ -22,6 +21,7 @@
 #include "executor/nodeSamplescan.h"
 #include "miscadmin.h"
 #include "pgstat.h"
+#include "storage/bufmgr.h"
 #include "storage/predicate.h"
 #include "utils/builtins.h"
 #include "utils/rel.h"

src/backend/lib/bloomfilter.c

@@ -35,9 +35,9 @@
 
 #include <math.h>
 
-#include "access/hash.h"
 #include "lib/bloomfilter.h"
 #include "port/pg_bitutils.h"
+#include "utils/hashutils.h"
 
 #define MAX_HASH_FUNCS		10
 

src/backend/nodes/bitmapset.c

@@ -20,9 +20,10 @@
  */
 #include "postgres.h"
 
-#include "access/hash.h"
+#include "nodes/bitmapset.h"
 #include "nodes/pg_list.h"
 #include "port/pg_bitutils.h"
+#include "utils/hashutils.h"
 
 
 #define WORDNUM(x)	((x) / BITS_PER_BITMAPWORD)

src/backend/storage/file/sharedfileset.c

@@ -18,13 +18,15 @@
 
 #include "postgres.h"
 
-#include "access/hash.h"
+#include <limits.h>
+
 #include "catalog/pg_tablespace.h"
 #include "commands/tablespace.h"
 #include "miscadmin.h"
 #include "storage/dsm.h"
 #include "storage/sharedfileset.h"
 #include "utils/builtins.h"
+#include "utils/hashutils.h"
 
 static void SharedFileSetOnDetach(dsm_segment *segment, Datum datum);
 static void SharedFileSetPath(char *path, SharedFileSet *fileset, Oid tablespace);

src/backend/tsearch/ts_typanalyze.c

@@ -13,12 +13,12 @@
  */
 #include "postgres.h"
 
-#include "access/hash.h"
 #include "catalog/pg_collation.h"
 #include "catalog/pg_operator.h"
 #include "commands/vacuum.h"
 #include "tsearch/ts_type.h"
 #include "utils/builtins.h"
+#include "utils/hashutils.h"
 
 
 /* A hash key for lexemes */

src/backend/utils/adt/acl.c

@@ -16,7 +16,6 @@
 
 #include <ctype.h>
 
-#include "access/hash.h"
 #include "access/htup_details.h"
 #include "catalog/catalog.h"
 #include "catalog/namespace.h"
@@ -33,6 +32,7 @@
 #include "utils/acl.h"
 #include "utils/builtins.h"
 #include "utils/catcache.h"
+#include "utils/hashutils.h"
 #include "utils/inval.h"
 #include "utils/lsyscache.h"
 #include "utils/memutils.h"

src/backend/utils/adt/arrayfuncs.c

@@ -17,7 +17,6 @@
 #include <ctype.h>
 #include <math.h>
 
-#include "access/hash.h"
 #include "access/htup_details.h"
 #include "catalog/pg_type.h"
 #include "funcapi.h"

src/backend/utils/adt/date.c

@@ -20,7 +20,6 @@
 #include <float.h>
 #include <time.h>
 
-#include "access/hash.h"
 #include "access/xact.h"
 #include "libpq/pqformat.h"
 #include "miscadmin.h"
@@ -30,6 +29,7 @@
 #include "utils/builtins.h"
 #include "utils/date.h"
 #include "utils/datetime.h"
+#include "utils/hashutils.h"
 #include "utils/sortsupport.h"
 
 /*

src/backend/utils/adt/jsonb_gin.c

@@ -14,11 +14,11 @@
 #include "postgres.h"
 
 #include "access/gin.h"
-#include "access/hash.h"
 #include "access/stratnum.h"
 #include "catalog/pg_collation.h"
 #include "catalog/pg_type.h"
 #include "utils/builtins.h"
+#include "utils/hashutils.h"
 #include "utils/jsonb.h"
 #include "utils/varlena.h"
 

src/backend/utils/adt/jsonb_util.c

@@ -13,10 +13,10 @@
  */
 #include "postgres.h"
 
-#include "access/hash.h"
 #include "catalog/pg_collation.h"
 #include "miscadmin.h"
 #include "utils/builtins.h"
+#include "utils/hashutils.h"
 #include "utils/jsonb.h"
 #include "utils/memutils.h"
 #include "utils/varlena.h"

src/backend/utils/adt/mac.c

@@ -13,12 +13,12 @@
 
 #include "postgres.h"
 
-#include "access/hash.h"
 #include "lib/hyperloglog.h"
 #include "libpq/pqformat.h"
 #include "port/pg_bswap.h"
 #include "utils/builtins.h"
 #include "utils/guc.h"
+#include "utils/hashutils.h"
 #include "utils/inet.h"
 #include "utils/sortsupport.h"
 

src/backend/utils/adt/mac8.c

@@ -21,9 +21,9 @@
 
 #include "postgres.h"
 
-#include "access/hash.h"
 #include "libpq/pqformat.h"
 #include "utils/builtins.h"
+#include "utils/hashutils.h"
 #include "utils/inet.h"
 
 /*

src/backend/utils/adt/network.c

@@ -12,7 +12,7 @@
 #include <netinet/in.h>
 #include <arpa/inet.h>
 
-#include "access/hash.h"
+#include "access/stratnum.h"
 #include "catalog/pg_opfamily.h"
 #include "catalog/pg_type.h"
 #include "common/ip.h"
@@ -24,6 +24,7 @@
 #include "nodes/supportnodes.h"
 #include "utils/builtins.h"
 #include "utils/fmgroids.h"
+#include "utils/hashutils.h"
 #include "utils/inet.h"
 #include "utils/lsyscache.h"
 

src/backend/utils/adt/numeric.c

@@ -26,7 +26,6 @@
 #include <limits.h>
 #include <math.h>
 
-#include "access/hash.h"
 #include "catalog/pg_type.h"
 #include "common/int.h"
 #include "funcapi.h"
@@ -39,6 +38,7 @@
 #include "utils/builtins.h"
 #include "utils/float.h"
 #include "utils/guc.h"
+#include "utils/hashutils.h"
 #include "utils/int8.h"
 #include "utils/numeric.h"
 #include "utils/sortsupport.h"

src/backend/utils/adt/pg_lsn.c

@@ -13,7 +13,6 @@
  */
 #include "postgres.h"
 
-#include "access/hash.h"
 #include "funcapi.h"
 #include "libpq/pqformat.h"
 #include "utils/builtins.h"

src/backend/utils/adt/rangetypes.c

@@ -30,12 +30,13 @@
  */
 #include "postgres.h"
 
-#include "access/hash.h"
+#include "access/tupmacs.h"
 #include "lib/stringinfo.h"
 #include "libpq/pqformat.h"
 #include "miscadmin.h"
 #include "utils/builtins.h"
 #include "utils/date.h"
+#include "utils/hashutils.h"
 #include "utils/int8.h"
 #include "utils/lsyscache.h"
 #include "utils/rangetypes.h"

src/backend/utils/adt/tid.c

@@ -20,7 +20,6 @@
 #include <math.h>
 #include <limits.h>
 
-#include "access/hash.h"
 #include "access/heapam.h"
 #include "access/sysattr.h"
 #include "catalog/namespace.h"
@@ -30,6 +29,7 @@
 #include "parser/parsetree.h"
 #include "utils/acl.h"
 #include "utils/builtins.h"
+#include "utils/hashutils.h"
 #include "utils/rel.h"
 #include "utils/snapmgr.h"
 #include "utils/varlena.h"

src/backend/utils/adt/timestamp.c

@@ -20,7 +20,6 @@
 #include <limits.h>
 #include <sys/time.h>
 
-#include "access/hash.h"
 #include "access/xact.h"
 #include "catalog/pg_type.h"
 #include "common/int128.h"

src/backend/utils/adt/uuid.c

@@ -13,12 +13,12 @@
 
 #include "postgres.h"
 
-#include "access/hash.h"
 #include "lib/hyperloglog.h"
 #include "libpq/pqformat.h"
 #include "port/pg_bswap.h"
 #include "utils/builtins.h"
 #include "utils/guc.h"
+#include "utils/hashutils.h"
 #include "utils/sortsupport.h"
 #include "utils/uuid.h"
 

src/backend/utils/adt/varchar.c

@@ -14,8 +14,6 @@
  */
 #include "postgres.h"
 
-
-#include "access/hash.h"
 #include "access/tuptoaster.h"
 #include "catalog/pg_collation.h"
 #include "catalog/pg_type.h"
@@ -24,6 +22,7 @@
 #include "nodes/supportnodes.h"
 #include "utils/array.h"
 #include "utils/builtins.h"
+#include "utils/hashutils.h"
 #include "utils/varlena.h"
 #include "mb/pg_wchar.h"
 

src/backend/utils/adt/varlena.c

@@ -17,7 +17,6 @@
 #include <ctype.h>
 #include <limits.h>
 
-#include "access/hash.h"
 #include "access/tuptoaster.h"
 #include "catalog/pg_collation.h"
 #include "catalog/pg_type.h"
@@ -30,6 +29,7 @@
 #include "regex/regex.h"
 #include "utils/builtins.h"
 #include "utils/bytea.h"
+#include "utils/hashutils.h"
 #include "utils/lsyscache.h"
 #include "utils/memutils.h"
 #include "utils/pg_locale.h"

src/backend/utils/cache/catcache.c

@@ -15,7 +15,6 @@
 #include "postgres.h"
 
 #include "access/genam.h"
-#include "access/hash.h"
 #include "access/relscan.h"
 #include "access/sysattr.h"
 #include "access/table.h"

src/backend/utils/cache/relcache.c

@@ -30,7 +30,6 @@
 #include <fcntl.h>
 #include <unistd.h>
 
-#include "access/hash.h"
 #include "access/htup_details.h"
 #include "access/multixact.h"
 #include "access/nbtree.h"

src/backend/utils/resowner/resowner.c

@@ -20,11 +20,12 @@
  */
 #include "postgres.h"
 
-#include "access/hash.h"
 #include "jit/jit.h"
+#include "storage/bufmgr.h"
 #include "storage/ipc.h"
 #include "storage/predicate.h"
 #include "storage/proc.h"
+#include "utils/hashutils.h"
 #include "utils/memutils.h"
 #include "utils/rel.h"
 #include "utils/resowner_private.h"

src/backend/utils/sort/tuplesort.c

@@ -96,9 +96,9 @@
 
 #include <limits.h>
 
+#include "access/hash.h"
 #include "access/htup_details.h"
 #include "access/nbtree.h"
-#include "access/hash.h"
 #include "catalog/index.h"
 #include "catalog/pg_am.h"
 #include "commands/tablespace.h"

src/include/access/hash.h

@@ -24,6 +24,7 @@
 #include "lib/stringinfo.h"
 #include "storage/bufmgr.h"
 #include "storage/lockdefs.h"
+#include "utils/hashutils.h"
 #include "utils/hsearch.h"
 #include "utils/relcache.h"
 
@@ -38,17 +39,6 @@ typedef uint32 Bucket;
 #define BUCKET_TO_BLKNO(metap,B) \
 		((BlockNumber) ((B) + ((B) ? (metap)->hashm_spares[_hash_spareindex((B)+1)-1] : 0)) + 1)
 
-/*
- * Rotate the high 32 bits and the low 32 bits separately.  The standard
- * hash function sometimes rotates the low 32 bits by one bit when
- * combining elements.  We want extended hash functions to be compatible with
- * that algorithm when the seed is 0, so we can't just do a normal rotation.
- * This works, though.
- */
-#define ROTATE_HIGH_AND_LOW_32BITS(v) \
-	((((v) << 1) & UINT64CONST(0xfffffffefffffffe)) | \
-	(((v) >> 31) & UINT64CONST(0x100000001)))
-
 /*
  * Special space for hash index pages.
  *
@@ -333,12 +323,6 @@ typedef HashMetaPageData *HashMetaPage;
 #define HASH_WRITE		BUFFER_LOCK_EXCLUSIVE
 #define HASH_NOLOCK		(-1)
 
-/*
- *	Strategy number. There's only one valid strategy for hashing: equality.
- */
-#define HTEqualStrategyNumber			1
-#define HTMaxStrategyNumber				1
-
 /*
  * When a new operator class is declared, we require that the user supply
  * us with an amproc function for hashing a key of the new type, returning
@@ -380,12 +364,6 @@ extern IndexBulkDeleteResult *hashvacuumcleanup(IndexVacuumInfo *info,
 extern bytea *hashoptions(Datum reloptions, bool validate);
 extern bool hashvalidate(Oid opclassoid);
 
-extern Datum hash_any(register const unsigned char *k, register int keylen);
-extern Datum hash_any_extended(register const unsigned char *k,
-				  register int keylen, uint64 seed);
-extern Datum hash_uint32(uint32 k);
-extern Datum hash_uint32_extended(uint32 k, uint64 seed);
-
 /* private routines */
 
 /* hashinsert.c */

src/include/access/stratnum.h

@@ -34,6 +34,13 @@ typedef uint16 StrategyNumber;
 
 #define BTMaxStrategyNumber				5
 
+/*
+ *	Strategy numbers for hash indexes. There's only one valid strategy for
+ *	hashing: equality.
+ */
+#define HTEqualStrategyNumber			1
+
+#define HTMaxStrategyNumber				1
 
 /*
  * Strategy numbers common to (some) GiST, SP-GiST and BRIN opclasses.

src/include/utils/hashutils.h

@@ -7,6 +7,25 @@
 #ifndef HASHUTILS_H
 #define HASHUTILS_H
 
+
+/*
+ * Rotate the high 32 bits and the low 32 bits separately.  The standard
+ * hash function sometimes rotates the low 32 bits by one bit when
+ * combining elements.  We want extended hash functions to be compatible with
+ * that algorithm when the seed is 0, so we can't just do a normal rotation.
+ * This works, though.
+ */
+#define ROTATE_HIGH_AND_LOW_32BITS(v) \
+	((((v) << 1) & UINT64CONST(0xfffffffefffffffe)) | \
+	(((v) >> 31) & UINT64CONST(0x100000001)))
+
+
+extern Datum hash_any(register const unsigned char *k, register int keylen);
+extern Datum hash_any_extended(register const unsigned char *k,
+				  register int keylen, uint64 seed);
+extern Datum hash_uint32(uint32 k);
+extern Datum hash_uint32_extended(uint32 k, uint64 seed);
+
 /*
  * Combine two 32-bit hash values, resulting in another hash value, with
  * decent bit mixing.