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c7b8998ebb
Change pg_bsd_indent to follow upstream rules for placement of comments
to the right of code, and remove pgindent hack that caused comments
following #endif to not obey the general rule.
Commit e3860ffa4d wasn't actually using
the published version of pg_bsd_indent, but a hacked-up version that
tried to minimize the amount of movement of comments to the right of
code. The situation of interest is where such a comment has to be
moved to the right of its default placement at column 33 because there's
code there. BSD indent has always moved right in units of tab stops
in such cases --- but in the previous incarnation, indent was working
in 8-space tab stops, while now it knows we use 4-space tabs. So the
net result is that in about half the cases, such comments are placed
one tab stop left of before. This is better all around: it leaves
more room on the line for comment text, and it means that in such
cases the comment uniformly starts at the next 4-space tab stop after
the code, rather than sometimes one and sometimes two tabs after.
Also, ensure that comments following #endif are indented the same
as comments following other preprocessor commands such as #else.
That inconsistency turns out to have been self-inflicted damage
from a poorly-thought-through post-indent "fixup" in pgindent.
This patch is much less interesting than the first round of indent
changes, but also bulkier, so I thought it best to separate the effects.
Discussion: https://postgr.es/m/E1dAmxK-0006EE-1r@gemulon.postgresql.org
Discussion: https://postgr.es/m/30527.1495162840@sss.pgh.pa.us
165 lines
4.2 KiB
C
165 lines
4.2 KiB
C
/*-------------------------------------------------------------------------
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*
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* itemptr.h
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* POSTGRES disk item pointer definitions.
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*
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*
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* Portions Copyright (c) 1996-2017, PostgreSQL Global Development Group
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* Portions Copyright (c) 1994, Regents of the University of California
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*
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* src/include/storage/itemptr.h
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*
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*-------------------------------------------------------------------------
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*/
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#ifndef ITEMPTR_H
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#define ITEMPTR_H
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#include "storage/block.h"
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#include "storage/off.h"
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/*
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* ItemPointer:
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*
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* This is a pointer to an item within a disk page of a known file
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* (for example, a cross-link from an index to its parent table).
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* blkid tells us which block, posid tells us which entry in the linp
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* (ItemIdData) array we want.
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*
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* Note: because there is an item pointer in each tuple header and index
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* tuple header on disk, it's very important not to waste space with
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* structure padding bytes. The struct is designed to be six bytes long
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* (it contains three int16 fields) but a few compilers will pad it to
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* eight bytes unless coerced. We apply appropriate persuasion where
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* possible. If your compiler can't be made to play along, you'll waste
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* lots of space.
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*/
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typedef struct ItemPointerData
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{
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BlockIdData ip_blkid;
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OffsetNumber ip_posid;
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}
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/* If compiler understands packed and aligned pragmas, use those */
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#if defined(pg_attribute_packed) && defined(pg_attribute_aligned)
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pg_attribute_packed()
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pg_attribute_aligned(2)
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#endif
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ItemPointerData;
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typedef ItemPointerData *ItemPointer;
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/* ----------------
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* support macros
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* ----------------
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*/
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/*
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* ItemPointerIsValid
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* True iff the disk item pointer is not NULL.
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*/
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#define ItemPointerIsValid(pointer) \
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((bool) (PointerIsValid(pointer) && ((pointer)->ip_posid != 0)))
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/*
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* ItemPointerGetBlockNumberNoCheck
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* Returns the block number of a disk item pointer.
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*/
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#define ItemPointerGetBlockNumberNoCheck(pointer) \
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( \
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BlockIdGetBlockNumber(&(pointer)->ip_blkid) \
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)
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/*
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* ItemPointerGetBlockNumber
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* As above, but verifies that the item pointer looks valid.
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*/
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#define ItemPointerGetBlockNumber(pointer) \
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( \
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AssertMacro(ItemPointerIsValid(pointer)), \
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ItemPointerGetBlockNumberNoCheck(pointer) \
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)
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/*
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* ItemPointerGetOffsetNumberNoCheck
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* Returns the offset number of a disk item pointer.
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*/
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#define ItemPointerGetOffsetNumberNoCheck(pointer) \
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( \
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(pointer)->ip_posid \
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)
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/*
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* ItemPointerGetOffsetNumber
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* As above, but verifies that the item pointer looks valid.
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*/
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#define ItemPointerGetOffsetNumber(pointer) \
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( \
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AssertMacro(ItemPointerIsValid(pointer)), \
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ItemPointerGetOffsetNumberNoCheck(pointer) \
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)
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/*
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* ItemPointerSet
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* Sets a disk item pointer to the specified block and offset.
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*/
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#define ItemPointerSet(pointer, blockNumber, offNum) \
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( \
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AssertMacro(PointerIsValid(pointer)), \
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BlockIdSet(&((pointer)->ip_blkid), blockNumber), \
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(pointer)->ip_posid = offNum \
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)
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/*
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* ItemPointerSetBlockNumber
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* Sets a disk item pointer to the specified block.
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*/
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#define ItemPointerSetBlockNumber(pointer, blockNumber) \
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( \
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AssertMacro(PointerIsValid(pointer)), \
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BlockIdSet(&((pointer)->ip_blkid), blockNumber) \
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)
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/*
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* ItemPointerSetOffsetNumber
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* Sets a disk item pointer to the specified offset.
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*/
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#define ItemPointerSetOffsetNumber(pointer, offsetNumber) \
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( \
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AssertMacro(PointerIsValid(pointer)), \
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(pointer)->ip_posid = (offsetNumber) \
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)
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/*
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* ItemPointerCopy
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* Copies the contents of one disk item pointer to another.
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*
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* Should there ever be padding in an ItemPointer this would need to be handled
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* differently as it's used as hash key.
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*/
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#define ItemPointerCopy(fromPointer, toPointer) \
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( \
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AssertMacro(PointerIsValid(toPointer)), \
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AssertMacro(PointerIsValid(fromPointer)), \
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*(toPointer) = *(fromPointer) \
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)
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/*
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* ItemPointerSetInvalid
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* Sets a disk item pointer to be invalid.
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*/
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#define ItemPointerSetInvalid(pointer) \
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( \
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AssertMacro(PointerIsValid(pointer)), \
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BlockIdSet(&((pointer)->ip_blkid), InvalidBlockNumber), \
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(pointer)->ip_posid = InvalidOffsetNumber \
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)
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/* ----------------
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* externs
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* ----------------
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*/
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extern bool ItemPointerEquals(ItemPointer pointer1, ItemPointer pointer2);
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extern int32 ItemPointerCompare(ItemPointer arg1, ItemPointer arg2);
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#endif /* ITEMPTR_H */
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