sharpetronics/PostgreSQL
1
0
Fork 0
mirror of https://github.com/postgres/postgres.git synced 2025-06-05 00:02:04 -04:00
Code Issues Projects Releases Wiki Activity

Mark constantly allocated dest receiver as const.

Browse Source 
This allows the compiler / linker to mark affected pages as read-only.

Doing so requires casting constness away, as CreateDestReceiver()
returns both constant and non-constant dest receivers. That's fine
though, as any modification of the statically allocated receivers
would already have been a bug (and would now be caught on some
platforms).

Discussion: https://postgr.es/m/20181015200754.7y7zfuzsoux2c4ya@alap3.anarazel.de
This commit is contained in:
Andres Freund 2018-10-16 12:05:50 -07:00
parent d1211c63f0
commit 93ca02e005
1 changed files with 21 additions and 12 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

33
src/backend/tcop/dest.c
View File

@ -67,29 +67,33 @@ donothingCleanup(DestReceiver *self)
* static DestReceiver structs for dest types needing no local state
* ----------------
*/
static DestReceiver donothingDR = {
static const DestReceiver donothingDR = {
donothingReceive, donothingStartup, donothingCleanup, donothingCleanup,
DestNone
};
static DestReceiver debugtupDR = {
static const DestReceiver debugtupDR = {
debugtup, debugStartup, donothingCleanup, donothingCleanup,
DestDebug
};
static DestReceiver printsimpleDR = {
static const DestReceiver printsimpleDR = {
printsimple, printsimple_startup, donothingCleanup, donothingCleanup,
DestRemoteSimple
};
static DestReceiver spi_printtupDR = {
static const DestReceiver spi_printtupDR = {
spi_printtup, spi_dest_startup, donothingCleanup, donothingCleanup,
DestSPI
};
/* Globally available receiver for DestNone */
DestReceiver *None_Receiver = &donothingDR;
/*
* Globally available receiver for DestNone.
*
* It's ok to cast the constness away as any modification of the none receiver
* would be a bug (which gets easier to catch this way).
*/
DestReceiver *None_Receiver = (DestReceiver *) &donothingDR;
/* ----------------
* BeginCommand - initialize the destination at start of command
@ -108,6 +112,11 @@ BeginCommand(const char *commandTag, CommandDest dest)
DestReceiver *
CreateDestReceiver(CommandDest dest)
{
/*
* It's ok to cast the constness away as any modification of the none receiver
* would be a bug (which gets easier to catch this way).
*/
switch (dest)
{
case DestRemote:
@ -115,16 +124,16 @@ CreateDestReceiver(CommandDest dest)
return printtup_create_DR(dest);
case DestRemoteSimple:
return &printsimpleDR;
return unconstify(DestReceiver *, &printsimpleDR);
case DestNone:
return &donothingDR;
return unconstify(DestReceiver *, &donothingDR);
case DestDebug:
return &debugtupDR;
return unconstify(DestReceiver *, &debugtupDR);
case DestSPI:
return &spi_printtupDR;
return unconstify(DestReceiver *, &spi_printtupDR);
case DestTuplestore:
return CreateTuplestoreDestReceiver();
@ -146,7 +155,7 @@ CreateDestReceiver(CommandDest dest)
}
/* should never get here */
return &donothingDR;
pg_unreachable();
}
/* ----------------