Use wrappers of PG_DETOAST_DATUM_PACKED() more.

This makes almost all core code follow the policy introduced in the
previous commit.  Specific decisions:

- Text search support functions with char* and length arguments, such as
  prsstart and lexize, may receive unaligned strings.  I doubt
  maintainers of non-core text search code will notice.

- Use plain VARDATA() on values detoasted or synthesized earlier in the
  same function.  Use VARDATA_ANY() on varlenas sourced outside the
  function, even if they happen to always have four-byte headers.  As an
  exception, retain the universal practice of using VARDATA() on return
  values of SendFunctionCall().

- Retain PG_GETARG_BYTEA_P() in pageinspect.  (Page images are too large
  for a one-byte header, so this misses no optimization.)  Sites that do
  not call get_page_from_raw() typically need the four-byte alignment.

- For now, do not change btree_gist.  Its use of four-byte headers in
  memory is partly entangled with storage of 4-byte headers inside
  GBT_VARKEY, on disk.

- For now, do not change gtrgm_consistent() or gtrgm_distance().  They
  incorporate the varlena header into a cache, and there are multiple
  credible implementation strategies to consider.

1 files changed, 5 insertions, 5 deletions

diff --git a/contrib/pageinspect/rawpage.c b/contrib/pageinspect/rawpage.c
index 1ccc3ff3204..a5def917511 100644
--- a/contrib/pageinspect/rawpage.c
+++ b/contrib/pageinspect/rawpage.c
@@ -45,7 +45,7 @@ PG_FUNCTION_INFO_V1(get_raw_page);
 Datum
 get_raw_page(PG_FUNCTION_ARGS)
 {
-	text	   *relname = PG_GETARG_TEXT_P(0);
+	text	   *relname = PG_GETARG_TEXT_PP(0);
 	uint32		blkno = PG_GETARG_UINT32(1);
 	bytea	   *raw_page;
 
@@ -74,8 +74,8 @@ PG_FUNCTION_INFO_V1(get_raw_page_fork);
 Datum
 get_raw_page_fork(PG_FUNCTION_ARGS)
 {
-	text	   *relname = PG_GETARG_TEXT_P(0);
-	text	   *forkname = PG_GETARG_TEXT_P(1);
+	text	   *relname = PG_GETARG_TEXT_PP(0);
+	text	   *forkname = PG_GETARG_TEXT_PP(1);
 	uint32		blkno = PG_GETARG_UINT32(2);
 	bytea	   *raw_page;
 	ForkNumber	forknum;
@@ -184,7 +184,7 @@ get_page_from_raw(bytea *raw_page)
 	Page		page;
 	int			raw_page_size;
 
-	raw_page_size = VARSIZE(raw_page) - VARHDRSZ;
+	raw_page_size = VARSIZE_ANY_EXHDR(raw_page);
 
 	if (raw_page_size != BLCKSZ)
 		ereport(ERROR,
@@ -195,7 +195,7 @@ get_page_from_raw(bytea *raw_page)
 
 	page = palloc(raw_page_size);
 
-	memcpy(page, VARDATA(raw_page), raw_page_size);
+	memcpy(page, VARDATA_ANY(raw_page), raw_page_size);
 
 	return page;
 }