From d0b4399d81f39decccb23fa38f772b71b51bf96a Mon Sep 17 00:00:00 2001 From: Neil Conway Date: Wed, 26 May 2004 04:41:50 +0000 Subject: Reimplement the linked list data structure used throughout the backend. In the past, we used a 'Lispy' linked list implementation: a "list" was merely a pointer to the head node of the list. The problem with that design is that it makes lappend() and length() linear time. This patch fixes that problem (and others) by maintaining a count of the list length and a pointer to the tail node along with each head node pointer. A "list" is now a pointer to a structure containing some meta-data about the list; the head and tail pointers in that structure refer to ListCell structures that maintain the actual linked list of nodes. The function names of the list API have also been changed to, I hope, be more logically consistent. By default, the old function names are still available; they will be disabled-by-default once the rest of the tree has been updated to use the new API names. --- src/backend/commands/comment.c | 60 +++++++++++++++++++++--------------------- 1 file changed, 30 insertions(+), 30 deletions(-) (limited to 'src/backend/commands/comment.c') diff --git a/src/backend/commands/comment.c b/src/backend/commands/comment.c index 423ab97570a..4c0d65038b2 100644 --- a/src/backend/commands/comment.c +++ b/src/backend/commands/comment.c @@ -7,7 +7,7 @@ * Copyright (c) 1996-2003, PostgreSQL Global Development Group * * IDENTIFICATION - * $PostgreSQL: pgsql/src/backend/commands/comment.c,v 1.76 2004/03/08 21:35:59 momjian Exp $ + * $PostgreSQL: pgsql/src/backend/commands/comment.c,v 1.77 2004/05/26 04:41:10 neilc Exp $ * *------------------------------------------------------------------------- */ @@ -379,11 +379,11 @@ CommentAttribute(List *qualname, char *comment) AttrNumber attnum; /* Separate relname and attr name */ - nnames = length(qualname); + nnames = list_length(qualname); if (nnames < 2) /* parser messed up */ elog(ERROR, "must specify relation and attribute"); - relname = ltruncate(nnames - 1, listCopy(qualname)); - attrname = strVal(llast(qualname)); + relname = list_truncate(list_copy(qualname), nnames - 1); + attrname = strVal(lfirst(list_tail(qualname))); /* Open the containing relation to ensure it won't go away meanwhile */ rel = makeRangeVarFromNameList(relname); @@ -429,11 +429,11 @@ CommentDatabase(List *qualname, char *comment) char *database; Oid oid; - if (length(qualname) != 1) + if (list_length(qualname) != 1) ereport(ERROR, (errcode(ERRCODE_SYNTAX_ERROR), errmsg("database name may not be qualified"))); - database = strVal(lfirst(qualname)); + database = strVal(linitial(qualname)); /* * We cannot currently support cross-database comments (since other @@ -493,11 +493,11 @@ CommentNamespace(List *qualname, char *comment) Oid classoid; char *namespace; - if (length(qualname) != 1) + if (list_length(qualname) != 1) ereport(ERROR, (errcode(ERRCODE_SYNTAX_ERROR), errmsg("schema name may not be qualified"))); - namespace = strVal(lfirst(qualname)); + namespace = strVal(linitial(qualname)); oid = GetSysCacheOid(NAMESPACENAME, CStringGetDatum(namespace), @@ -548,7 +548,7 @@ CommentRule(List *qualname, char *comment) AclResult aclcheck; /* Separate relname and trig name */ - nnames = length(qualname); + nnames = list_length(qualname); if (nnames == 1) { /* Old-style: only a rule name is given */ @@ -556,7 +556,7 @@ CommentRule(List *qualname, char *comment) HeapScanDesc scanDesc; ScanKeyData scanKeyData; - rulename = strVal(lfirst(qualname)); + rulename = strVal(linitial(qualname)); /* Search pg_rewrite for such a rule */ ScanKeyInit(&scanKeyData, @@ -599,8 +599,8 @@ CommentRule(List *qualname, char *comment) { /* New-style: rule and relname both provided */ Assert(nnames >= 2); - relname = ltruncate(nnames - 1, listCopy(qualname)); - rulename = strVal(llast(qualname)); + relname = list_truncate(list_copy(qualname), nnames - 1); + rulename = strVal(lfirst(list_tail(qualname))); /* Open the owning relation to ensure it won't go away meanwhile */ rel = makeRangeVarFromNameList(relname); @@ -683,7 +683,7 @@ CommentType(List *typename, char *comment) static void CommentAggregate(List *aggregate, List *arguments, char *comment) { - TypeName *aggtype = (TypeName *) lfirst(arguments); + TypeName *aggtype = (TypeName *) linitial(arguments); Oid baseoid, oid; @@ -750,7 +750,7 @@ CommentProc(List *function, List *arguments, char *comment) static void CommentOperator(List *opername, List *arguments, char *comment) { - TypeName *typenode1 = (TypeName *) lfirst(arguments); + TypeName *typenode1 = (TypeName *) linitial(arguments); TypeName *typenode2 = (TypeName *) lsecond(arguments); Oid oid; Oid classoid; @@ -794,11 +794,11 @@ CommentTrigger(List *qualname, char *comment) Oid oid; /* Separate relname and trig name */ - nnames = length(qualname); + nnames = list_length(qualname); if (nnames < 2) /* parser messed up */ elog(ERROR, "must specify relation and trigger"); - relname = ltruncate(nnames - 1, listCopy(qualname)); - trigname = strVal(llast(qualname)); + relname = list_truncate(list_copy(qualname), nnames - 1); + trigname = strVal(lfirst(list_tail(qualname))); /* Open the owning relation to ensure it won't go away meanwhile */ rel = makeRangeVarFromNameList(relname); @@ -872,11 +872,11 @@ CommentConstraint(List *qualname, char *comment) Oid conOid = InvalidOid; /* Separate relname and constraint name */ - nnames = length(qualname); + nnames = list_length(qualname); if (nnames < 2) /* parser messed up */ elog(ERROR, "must specify relation and constraint"); - relName = ltruncate(nnames - 1, listCopy(qualname)); - conName = strVal(llast(qualname)); + relName = list_truncate(list_copy(qualname), nnames - 1); + conName = strVal(lfirst(list_tail(qualname))); /* Open the owning relation to ensure it won't go away meanwhile */ rel = makeRangeVarFromNameList(relName); @@ -985,11 +985,11 @@ CommentLanguage(List *qualname, char *comment) Oid classoid; char *language; - if (length(qualname) != 1) + if (list_length(qualname) != 1) ereport(ERROR, (errcode(ERRCODE_SYNTAX_ERROR), errmsg("language name may not be qualified"))); - language = strVal(lfirst(qualname)); + language = strVal(linitial(qualname)); oid = GetSysCacheOid(LANGNAME, CStringGetDatum(language), @@ -1032,8 +1032,8 @@ CommentOpClass(List *qualname, List *arguments, char *comment) Oid classoid; HeapTuple tuple; - Assert(length(arguments) == 1); - amname = strVal(lfirst(arguments)); + Assert(list_length(arguments) == 1); + amname = strVal(linitial(arguments)); /* * Get the access method's OID. @@ -1118,8 +1118,8 @@ CommentLargeObject(List *qualname, char *comment) Oid classoid; Node *node; - Assert(length(qualname) == 1); - node = (Node *) lfirst(qualname); + Assert(list_length(qualname) == 1); + node = (Node *) linitial(qualname); switch (nodeTag(node)) { @@ -1176,11 +1176,11 @@ CommentCast(List *qualname, List *arguments, char *comment) Oid castOid; Oid classoid; - Assert(length(qualname) == 1); - sourcetype = (TypeName *) lfirst(qualname); + Assert(list_length(qualname) == 1); + sourcetype = (TypeName *) linitial(qualname); Assert(IsA(sourcetype, TypeName)); - Assert(length(arguments) == 1); - targettype = (TypeName *) lfirst(arguments); + Assert(list_length(arguments) == 1); + targettype = (TypeName *) linitial(arguments); Assert(IsA(targettype, TypeName)); sourcetypeid = typenameTypeId(sourcetype); -- cgit v1.2.3