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.

3 files changed, 26 insertions, 25 deletions

diff --git a/src/backend/tsearch/dict.c b/src/backend/tsearch/dict.c
index 87ee8bfe2e0..ba8a3d79a83 100644
--- a/src/backend/tsearch/dict.c
+++ b/src/backend/tsearch/dict.c
@@ -26,7 +26,7 @@ Datum
 ts_lexize(PG_FUNCTION_ARGS)
 {
 	Oid			dictId = PG_GETARG_OID(0);
-	text	   *in = PG_GETARG_TEXT_P(1);
+	text	   *in = PG_GETARG_TEXT_PP(1);
 	ArrayType  *a;
 	TSDictionaryCacheEntry *dict;
 	TSLexeme   *res,
@@ -38,8 +38,8 @@ ts_lexize(PG_FUNCTION_ARGS)
 
 	res = (TSLexeme *) DatumGetPointer(FunctionCall4(&dict->lexize,
 											 PointerGetDatum(dict->dictData),
-												PointerGetDatum(VARDATA(in)),
-									   Int32GetDatum(VARSIZE(in) - VARHDRSZ),
+											PointerGetDatum(VARDATA_ANY(in)),
+										Int32GetDatum(VARSIZE_ANY_EXHDR(in)),
 												  PointerGetDatum(&dstate)));
 
 	if (dstate.getnext)
@@ -47,8 +47,8 @@ ts_lexize(PG_FUNCTION_ARGS)
 		dstate.isend = true;
 		ptr = (TSLexeme *) DatumGetPointer(FunctionCall4(&dict->lexize,
 											 PointerGetDatum(dict->dictData),
-												PointerGetDatum(VARDATA(in)),
-									   Int32GetDatum(VARSIZE(in) - VARHDRSZ),
+											PointerGetDatum(VARDATA_ANY(in)),
+										Int32GetDatum(VARSIZE_ANY_EXHDR(in)),
 												  PointerGetDatum(&dstate)));
 		if (ptr != NULL)
 			res = ptr;
diff --git a/src/backend/tsearch/to_tsany.c b/src/backend/tsearch/to_tsany.c
index 6e5de8f9202..398a781c037 100644
--- a/src/backend/tsearch/to_tsany.c
+++ b/src/backend/tsearch/to_tsany.c
@@ -216,19 +216,19 @@ Datum
 to_tsvector_byid(PG_FUNCTION_ARGS)
 {
 	Oid			cfgId = PG_GETARG_OID(0);
-	text	   *in = PG_GETARG_TEXT_P(1);
+	text	   *in = PG_GETARG_TEXT_PP(1);
 	ParsedText	prs;
 	TSVector	out;
 
-	prs.lenwords = (VARSIZE(in) - VARHDRSZ) / 6;		/* just estimation of
-														 * word's number */
+	prs.lenwords = VARSIZE_ANY_EXHDR(in) / 6;	/* just estimation of word's
+												 * number */
 	if (prs.lenwords == 0)
 		prs.lenwords = 2;
 	prs.curwords = 0;
 	prs.pos = 0;
 	prs.words = (ParsedWord *) palloc(sizeof(ParsedWord) * prs.lenwords);
 
-	parsetext(cfgId, &prs, VARDATA(in), VARSIZE(in) - VARHDRSZ);
+	parsetext(cfgId, &prs, VARDATA_ANY(in), VARSIZE_ANY_EXHDR(in));
 	PG_FREE_IF_COPY(in, 1);
 
 	if (prs.curwords)
@@ -247,7 +247,7 @@ to_tsvector_byid(PG_FUNCTION_ARGS)
 Datum
 to_tsvector(PG_FUNCTION_ARGS)
 {
-	text	   *in = PG_GETARG_TEXT_P(0);
+	text	   *in = PG_GETARG_TEXT_PP(0);
 	Oid			cfgId;
 
 	cfgId = getTSCurrentConfig(true);
@@ -362,7 +362,7 @@ pushval_morph(Datum opaque, TSQueryParserState state, char *strval, int lenval,
 Datum
 to_tsquery_byid(PG_FUNCTION_ARGS)
 {
-	text	   *in = PG_GETARG_TEXT_P(1);
+	text	   *in = PG_GETARG_TEXT_PP(1);
 	TSQuery		query;
 	MorphOpaque data;
 
@@ -380,7 +380,7 @@ to_tsquery_byid(PG_FUNCTION_ARGS)
 Datum
 to_tsquery(PG_FUNCTION_ARGS)
 {
-	text	   *in = PG_GETARG_TEXT_P(0);
+	text	   *in = PG_GETARG_TEXT_PP(0);
 	Oid			cfgId;
 
 	cfgId = getTSCurrentConfig(true);
@@ -392,7 +392,7 @@ to_tsquery(PG_FUNCTION_ARGS)
 Datum
 plainto_tsquery_byid(PG_FUNCTION_ARGS)
 {
-	text	   *in = PG_GETARG_TEXT_P(1);
+	text	   *in = PG_GETARG_TEXT_PP(1);
 	TSQuery		query;
 	MorphOpaque data;
 
@@ -410,7 +410,7 @@ plainto_tsquery_byid(PG_FUNCTION_ARGS)
 Datum
 plainto_tsquery(PG_FUNCTION_ARGS)
 {
-	text	   *in = PG_GETARG_TEXT_P(0);
+	text	   *in = PG_GETARG_TEXT_PP(0);
 	Oid			cfgId;
 
 	cfgId = getTSCurrentConfig(true);
@@ -423,7 +423,7 @@ plainto_tsquery(PG_FUNCTION_ARGS)
 Datum
 phraseto_tsquery_byid(PG_FUNCTION_ARGS)
 {
-	text	   *in = PG_GETARG_TEXT_P(1);
+	text	   *in = PG_GETARG_TEXT_PP(1);
 	TSQuery		query;
 	MorphOpaque data;
 
@@ -441,7 +441,7 @@ phraseto_tsquery_byid(PG_FUNCTION_ARGS)
 Datum
 phraseto_tsquery(PG_FUNCTION_ARGS)
 {
-	text	   *in = PG_GETARG_TEXT_P(0);
+	text	   *in = PG_GETARG_TEXT_PP(0);
 	Oid			cfgId;
 
 	cfgId = getTSCurrentConfig(true);
diff --git a/src/backend/tsearch/wparser.c b/src/backend/tsearch/wparser.c
index 8ca1c62713e..d8f2f65542b 100644
--- a/src/backend/tsearch/wparser.c
+++ b/src/backend/tsearch/wparser.c
@@ -123,7 +123,7 @@ ts_token_type_byname(PG_FUNCTION_ARGS)
 
 	if (SRF_IS_FIRSTCALL())
 	{
-		text	   *prsname = PG_GETARG_TEXT_P(0);
+		text	   *prsname = PG_GETARG_TEXT_PP(0);
 		Oid			prsId;
 
 		funcctx = SRF_FIRSTCALL_INIT();
@@ -172,8 +172,8 @@ prs_setup_firstcall(FuncCallContext *funcctx, Oid prsid, text *txt)
 	st->list = (LexemeEntry *) palloc(sizeof(LexemeEntry) * st->len);
 
 	prsdata = (void *) DatumGetPointer(FunctionCall2(&prs->prsstart,
-											   PointerGetDatum(VARDATA(txt)),
-									Int32GetDatum(VARSIZE(txt) - VARHDRSZ)));
+										   PointerGetDatum(VARDATA_ANY(txt)),
+									 Int32GetDatum(VARSIZE_ANY_EXHDR(txt))));
 
 	while ((type = DatumGetInt32(FunctionCall3(&prs->prstoken,
 											   PointerGetDatum(prsdata),
@@ -248,7 +248,7 @@ ts_parse_byid(PG_FUNCTION_ARGS)
 
 	if (SRF_IS_FIRSTCALL())
 	{
-		text	   *txt = PG_GETARG_TEXT_P(1);
+		text	   *txt = PG_GETARG_TEXT_PP(1);
 
 		funcctx = SRF_FIRSTCALL_INIT();
 		prs_setup_firstcall(funcctx, PG_GETARG_OID(0), txt);
@@ -270,8 +270,8 @@ ts_parse_byname(PG_FUNCTION_ARGS)
 
 	if (SRF_IS_FIRSTCALL())
 	{
-		text	   *prsname = PG_GETARG_TEXT_P(0);
-		text	   *txt = PG_GETARG_TEXT_P(1);
+		text	   *prsname = PG_GETARG_TEXT_PP(0);
+		text	   *txt = PG_GETARG_TEXT_PP(1);
 		Oid			prsId;
 
 		funcctx = SRF_FIRSTCALL_INIT();
@@ -289,9 +289,9 @@ ts_parse_byname(PG_FUNCTION_ARGS)
 Datum
 ts_headline_byid_opt(PG_FUNCTION_ARGS)
 {
-	text	   *in = PG_GETARG_TEXT_P(1);
+	text	   *in = PG_GETARG_TEXT_PP(1);
 	TSQuery		query = PG_GETARG_TSQUERY(2);
-	text	   *opt = (PG_NARGS() > 3 && PG_GETARG_POINTER(3)) ? PG_GETARG_TEXT_P(3) : NULL;
+	text	   *opt = (PG_NARGS() > 3 && PG_GETARG_POINTER(3)) ? PG_GETARG_TEXT_PP(3) : NULL;
 	HeadlineParsedText prs;
 	List	   *prsoptions;
 	text	   *out;
@@ -310,7 +310,8 @@ ts_headline_byid_opt(PG_FUNCTION_ARGS)
 	prs.lenwords = 32;
 	prs.words = (HeadlineWordEntry *) palloc(sizeof(HeadlineWordEntry) * prs.lenwords);
 
-	hlparsetext(cfg->cfgId, &prs, query, VARDATA(in), VARSIZE(in) - VARHDRSZ);
+	hlparsetext(cfg->cfgId, &prs, query,
+				VARDATA_ANY(in), VARSIZE_ANY_EXHDR(in));
 
 	if (opt)
 		prsoptions = deserialize_deflist(PointerGetDatum(opt));