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Renaming for new subscripting mechanism

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Over at patch https://commitfest.postgresql.org/21/1062/ Dmitry wants to
introduce a more generic subscription mechanism, which allows
subscripting not only arrays but also other object types such as JSONB.
That functionality is introduced in a largish invasive patch, out of
which this internal renaming patch was extracted.

Author: Dmitry Dolgov
Reviewed-by: Tom Lane, Arthur Zakirov
Discussion: https://postgr.es/m/CA+q6zcUK4EqPAu7XRRO5CCjMwhz5zvg+rfWuLzVoxp_5sKS6=w@mail.gmail.com
This commit is contained in:
Alvaro Herrera
2019-02-01 12:50:32 -03:00
parent f831d4accd
commit 558d77f20e
26 changed files with 555 additions and 523 deletions
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171
src/backend/executor/execExpr.c
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@ -67,9 +67,10 @@ static bool get_last_attnums_walker(Node *node, LastAttnumInfo *info);
static void ExecComputeSlotInfo(ExprState *state, ExprEvalStep *op);
static void ExecInitWholeRowVar(ExprEvalStep *scratch, Var *variable,
ExprState *state);
static void ExecInitArrayRef(ExprEvalStep *scratch, ArrayRef *aref,
ExprState *state,
Datum *resv, bool *resnull);
static void ExecInitSubscriptingRef(ExprEvalStep *scratch,
SubscriptingRef *sbsref,
ExprState *state,
Datum *resv, bool *resnull);
static bool isAssignmentIndirectionExpr(Expr *expr);
static void ExecInitCoerceToDomain(ExprEvalStep *scratch, CoerceToDomain *ctest,
ExprState *state,
@ -867,11 +868,11 @@ ExecInitExprRec(Expr *node, ExprState *state,
break;
}
case T_ArrayRef:
case T_SubscriptingRef:
{
ArrayRef *aref = (ArrayRef *) node;
SubscriptingRef *sbsref = (SubscriptingRef *) node;
ExecInitArrayRef(&scratch, aref, state, resv, resnull);
ExecInitSubscriptingRef(&scratch, sbsref, state, resv, resnull);
break;
}
@ -1186,13 +1187,14 @@ ExecInitExprRec(Expr *node, ExprState *state,
/*
* Use the CaseTestExpr mechanism to pass down the old
* value of the field being replaced; this is needed in
* case the newval is itself a FieldStore or ArrayRef that
* has to obtain and modify the old value. It's safe to
* reuse the CASE mechanism because there cannot be a CASE
* between here and where the value would be needed, and a
* field assignment can't be within a CASE either. (So
* saving and restoring innermost_caseval is just
* paranoia, but let's do it anyway.)
* case the newval is itself a FieldStore or
* SubscriptingRef that has to obtain and modify the old
* value. It's safe to reuse the CASE mechanism because
* there cannot be a CASE between here and where the value
* would be needed, and a field assignment can't be within
* a CASE either. (So saving and restoring
* innermost_caseval is just paranoia, but let's do it
* anyway.)
*
* Another non-obvious point is that it's safe to use the
* field's values[]/nulls[] entries as both the caseval
@ -2528,34 +2530,34 @@ ExecInitWholeRowVar(ExprEvalStep *scratch, Var *variable, ExprState *state)
}
/*
* Prepare evaluation of an ArrayRef expression.
* Prepare evaluation of a SubscriptingRef expression.
*/
static void
ExecInitArrayRef(ExprEvalStep *scratch, ArrayRef *aref,
ExprState *state, Datum *resv, bool *resnull)
ExecInitSubscriptingRef(ExprEvalStep *scratch, SubscriptingRef *sbsref,
ExprState *state, Datum *resv, bool *resnull)
{
bool isAssignment = (aref->refassgnexpr != NULL);
ArrayRefState *arefstate = palloc0(sizeof(ArrayRefState));
bool isAssignment = (sbsref->refassgnexpr != NULL);
SubscriptingRefState *sbsrefstate = palloc0(sizeof(SubscriptingRefState));
List *adjust_jumps = NIL;
ListCell *lc;
int i;
/* Fill constant fields of ArrayRefState */
arefstate->isassignment = isAssignment;
arefstate->refelemtype = aref->refelemtype;
arefstate->refattrlength = get_typlen(aref->refarraytype);
get_typlenbyvalalign(aref->refelemtype,
&arefstate->refelemlength,
&arefstate->refelembyval,
&arefstate->refelemalign);
/* Fill constant fields of SubscriptingRefState */
sbsrefstate->isassignment = isAssignment;
sbsrefstate->refelemtype = sbsref->refelemtype;
sbsrefstate->refattrlength = get_typlen(sbsref->refcontainertype);
get_typlenbyvalalign(sbsref->refelemtype,
&sbsrefstate->refelemlength,
&sbsrefstate->refelembyval,
&sbsrefstate->refelemalign);
/*
* Evaluate array input. It's safe to do so into resv/resnull, because we
* won't use that as target for any of the other subexpressions, and it'll
* be overwritten by the final EEOP_ARRAYREF_FETCH/ASSIGN step, which is
* be overwritten by the final EEOP_SBSREF_FETCH/ASSIGN step, which is
* pushed last.
*/
ExecInitExprRec(aref->refexpr, state, resv, resnull);
ExecInitExprRec(sbsref->refexpr, state, resv, resnull);
/*
* If refexpr yields NULL, and it's a fetch, then result is NULL. We can
@ -2572,87 +2574,87 @@ ExecInitArrayRef(ExprEvalStep *scratch, ArrayRef *aref,
}
/* Verify subscript list lengths are within limit */
if (list_length(aref->refupperindexpr) > MAXDIM)
if (list_length(sbsref->refupperindexpr) > MAXDIM)
ereport(ERROR,
(errcode(ERRCODE_PROGRAM_LIMIT_EXCEEDED),
errmsg("number of array dimensions (%d) exceeds the maximum allowed (%d)",
list_length(aref->refupperindexpr), MAXDIM)));
list_length(sbsref->refupperindexpr), MAXDIM)));
if (list_length(aref->reflowerindexpr) > MAXDIM)
if (list_length(sbsref->reflowerindexpr) > MAXDIM)
ereport(ERROR,
(errcode(ERRCODE_PROGRAM_LIMIT_EXCEEDED),
errmsg("number of array dimensions (%d) exceeds the maximum allowed (%d)",
list_length(aref->reflowerindexpr), MAXDIM)));
list_length(sbsref->reflowerindexpr), MAXDIM)));
/* Evaluate upper subscripts */
i = 0;
foreach(lc, aref->refupperindexpr)
foreach(lc, sbsref->refupperindexpr)
{
Expr *e = (Expr *) lfirst(lc);
/* When slicing, individual subscript bounds can be omitted */
if (!e)
{
arefstate->upperprovided[i] = false;
sbsrefstate->upperprovided[i] = false;
i++;
continue;
}
arefstate->upperprovided[i] = true;
sbsrefstate->upperprovided[i] = true;
/* Each subscript is evaluated into subscriptvalue/subscriptnull */
ExecInitExprRec(e, state,
&arefstate->subscriptvalue, &arefstate->subscriptnull);
&sbsrefstate->subscriptvalue, &sbsrefstate->subscriptnull);
/* ... and then ARRAYREF_SUBSCRIPT saves it into step's workspace */
scratch->opcode = EEOP_ARRAYREF_SUBSCRIPT;
scratch->d.arrayref_subscript.state = arefstate;
scratch->d.arrayref_subscript.off = i;
scratch->d.arrayref_subscript.isupper = true;
scratch->d.arrayref_subscript.jumpdone = -1; /* adjust later */
/* ... and then SBSREF_SUBSCRIPT saves it into step's workspace */
scratch->opcode = EEOP_SBSREF_SUBSCRIPT;
scratch->d.sbsref_subscript.state = sbsrefstate;
scratch->d.sbsref_subscript.off = i;
scratch->d.sbsref_subscript.isupper = true;
scratch->d.sbsref_subscript.jumpdone = -1; /* adjust later */
ExprEvalPushStep(state, scratch);
adjust_jumps = lappend_int(adjust_jumps,
state->steps_len - 1);
i++;
}
arefstate->numupper = i;
sbsrefstate->numupper = i;
/* Evaluate lower subscripts similarly */
i = 0;
foreach(lc, aref->reflowerindexpr)
foreach(lc, sbsref->reflowerindexpr)
{
Expr *e = (Expr *) lfirst(lc);
/* When slicing, individual subscript bounds can be omitted */
if (!e)
{
arefstate->lowerprovided[i] = false;
sbsrefstate->lowerprovided[i] = false;
i++;
continue;
}
arefstate->lowerprovided[i] = true;
sbsrefstate->lowerprovided[i] = true;
/* Each subscript is evaluated into subscriptvalue/subscriptnull */
ExecInitExprRec(e, state,
&arefstate->subscriptvalue, &arefstate->subscriptnull);
&sbsrefstate->subscriptvalue, &sbsrefstate->subscriptnull);
/* ... and then ARRAYREF_SUBSCRIPT saves it into step's workspace */
scratch->opcode = EEOP_ARRAYREF_SUBSCRIPT;
scratch->d.arrayref_subscript.state = arefstate;
scratch->d.arrayref_subscript.off = i;
scratch->d.arrayref_subscript.isupper = false;
scratch->d.arrayref_subscript.jumpdone = -1; /* adjust later */
/* ... and then SBSREF_SUBSCRIPT saves it into step's workspace */
scratch->opcode = EEOP_SBSREF_SUBSCRIPT;
scratch->d.sbsref_subscript.state = sbsrefstate;
scratch->d.sbsref_subscript.off = i;
scratch->d.sbsref_subscript.isupper = false;
scratch->d.sbsref_subscript.jumpdone = -1; /* adjust later */
ExprEvalPushStep(state, scratch);
adjust_jumps = lappend_int(adjust_jumps,
state->steps_len - 1);
i++;
}
arefstate->numlower = i;
sbsrefstate->numlower = i;
/* Should be impossible if parser is sane, but check anyway: */
if (arefstate->numlower != 0 &&
arefstate->numupper != arefstate->numlower)
if (sbsrefstate->numlower != 0 &&
sbsrefstate->numupper != sbsrefstate->numlower)
elog(ERROR, "upper and lower index lists are not same length");
if (isAssignment)
@ -2662,49 +2664,51 @@ ExecInitArrayRef(ExprEvalStep *scratch, ArrayRef *aref,
/*
* We might have a nested-assignment situation, in which the
* refassgnexpr is itself a FieldStore or ArrayRef that needs to
* obtain and modify the previous value of the array element or slice
* being replaced. If so, we have to extract that value from the
* array and pass it down via the CaseTestExpr mechanism. It's safe
* to reuse the CASE mechanism because there cannot be a CASE between
* here and where the value would be needed, and an array assignment
* can't be within a CASE either. (So saving and restoring
* refassgnexpr is itself a FieldStore or SubscriptingRef that needs
* to obtain and modify the previous value of the array element or
* slice being replaced. If so, we have to extract that value from
* the array and pass it down via the CaseTestExpr mechanism. It's
* safe to reuse the CASE mechanism because there cannot be a CASE
* between here and where the value would be needed, and an array
* assignment can't be within a CASE either. (So saving and restoring
* innermost_caseval is just paranoia, but let's do it anyway.)
*
* Since fetching the old element might be a nontrivial expense, do it
* only if the argument actually needs it.
*/
if (isAssignmentIndirectionExpr(aref->refassgnexpr))
if (isAssignmentIndirectionExpr(sbsref->refassgnexpr))
{
scratch->opcode = EEOP_ARRAYREF_OLD;
scratch->d.arrayref.state = arefstate;
scratch->opcode = EEOP_SBSREF_OLD;
scratch->d.sbsref.state = sbsrefstate;
ExprEvalPushStep(state, scratch);
}
/* ARRAYREF_OLD puts extracted value into prevvalue/prevnull */
/* SBSREF_OLD puts extracted value into prevvalue/prevnull */
save_innermost_caseval = state->innermost_caseval;
save_innermost_casenull = state->innermost_casenull;
state->innermost_caseval = &arefstate->prevvalue;
state->innermost_casenull = &arefstate->prevnull;
state->innermost_caseval = &sbsrefstate->prevvalue;
state->innermost_casenull = &sbsrefstate->prevnull;
/* evaluate replacement value into replacevalue/replacenull */
ExecInitExprRec(aref->refassgnexpr, state,
&arefstate->replacevalue, &arefstate->replacenull);
ExecInitExprRec(sbsref->refassgnexpr, state,
&sbsrefstate->replacevalue, &sbsrefstate->replacenull);
state->innermost_caseval = save_innermost_caseval;
state->innermost_casenull = save_innermost_casenull;
/* and perform the assignment */
scratch->opcode = EEOP_ARRAYREF_ASSIGN;
scratch->d.arrayref.state = arefstate;
scratch->opcode = EEOP_SBSREF_ASSIGN;
scratch->d.sbsref.state = sbsrefstate;
ExprEvalPushStep(state, scratch);
}
else
{
/* array fetch is much simpler */
scratch->opcode = EEOP_ARRAYREF_FETCH;
scratch->d.arrayref.state = arefstate;
scratch->opcode = EEOP_SBSREF_FETCH;
scratch->d.sbsref.state = sbsrefstate;
ExprEvalPushStep(state, scratch);
}
/* adjust jump targets */
@ -2712,10 +2716,10 @@ ExecInitArrayRef(ExprEvalStep *scratch, ArrayRef *aref,
{
ExprEvalStep *as = &state->steps[lfirst_int(lc)];
if (as->opcode == EEOP_ARRAYREF_SUBSCRIPT)
if (as->opcode == EEOP_SBSREF_SUBSCRIPT)
{
Assert(as->d.arrayref_subscript.jumpdone == -1);
as->d.arrayref_subscript.jumpdone = state->steps_len;
Assert(as->d.sbsref_subscript.jumpdone == -1);
as->d.sbsref_subscript.jumpdone = state->steps_len;
}
else
{
@ -2727,8 +2731,9 @@ ExecInitArrayRef(ExprEvalStep *scratch, ArrayRef *aref,
}
/*
* Helper for preparing ArrayRef expressions for evaluation: is expr a nested
* FieldStore or ArrayRef that needs the old element value passed down?
* Helper for preparing SubscriptingRef expressions for evaluation: is expr
* a nested FieldStore or SubscriptingRef that needs the old element value
* passed down?
*
* (We could use this in FieldStore too, but in that case passing the old
* value is so cheap there's no need.)
@ -2751,11 +2756,11 @@ isAssignmentIndirectionExpr(Expr *expr)
if (fstore->arg && IsA(fstore->arg, CaseTestExpr))
return true;
}
else if (IsA(expr, ArrayRef))
else if (IsA(expr, SubscriptingRef))
{
ArrayRef *arrayRef = (ArrayRef *) expr;
SubscriptingRef *sbsRef = (SubscriptingRef *) expr;
if (arrayRef->refexpr && IsA(arrayRef->refexpr, CaseTestExpr))
if (sbsRef->refexpr && IsA(sbsRef->refexpr, CaseTestExpr))
return true;
}
return false;