Re: [Tarantool-patches] [PATCH v1 05/21] sql: refactor PRINTF() function

[Mergen Imeev via Tarantool-patches <tarantool-patches@dev.tarantool.org>]

Thank you for the review! My answer, diff and new patch below. I also simplified
the code a bit.

On Fri, Oct 15, 2021 at 12:44:08AM +0200, Vladislav Shpilevoy wrote:
> Thanks for the patch!
> 
> > diff --git a/src/box/sql/func.c b/src/box/sql/func.c
> > index 863dbf1c4..f5040fb6e 100644
> > --- a/src/box/sql/func.c
> > +++ b/src/box/sql/func.c
> > @@ -846,6 +846,40 @@ func_octet_length(struct sql_context *ctx, int argc, struct Mem *argv)
> >  	mem_set_uint(ctx->pOut, arg->n);
> >  }
> >  
> > +/** Implementation of the PRINTF() function. */
> > +static void
> > +func_printf(struct sql_context *ctx, int argc, struct Mem *argv)
> > +{
> > +	if (argc < 1 || mem_is_null(&argv[0]))
> > +		return;
> > +	if (argc == 1 || !mem_is_str(&argv[0])) {
> > +		struct Mem *mem = ctx->pOut;
> > +		if (mem_copy(mem, &argv[0]) != 0 || mem_to_str(mem) != 0)
> > +			ctx->is_aborted = true;
> > +		return;
> > +	}
> > +	struct PrintfArguments pargs;
> > +	struct StrAccum acc;
> > +	char *format = argv[0].z;
> > +	struct sql *db = sql_get();
> > +
> > +	pargs.nArg = argc - 1;
> > +	pargs.nUsed = 0;
> > +	pargs.apArg = sqlDbMallocRawNN(db, (argc - 1) * sizeof(*pargs.apArg));
> > +	if (pargs.apArg == NULL) {
> > +		ctx->is_aborted = true;
> > +		return;
> > +	}
> > +	for (int i = 1; i < argc; ++i)
> > +		pargs.apArg[i - 1] = &argv[i];
> > +	sqlStrAccumInit(&acc, db, 0, 0, db->aLimit[SQL_LIMIT_LENGTH]);
> > +	acc.printfFlags = SQL_PRINTF_SQLFUNC;
> > +	sqlXPrintf(&acc, format, &pargs);
> > +	sqlDbFree(db, pargs.apArg);
> > +	if (mem_copy_str(ctx->pOut, sqlStrAccumFinish(&acc), acc.nChar) != 0)
> 
> It leaks now, because sqlStrAccumFinish is not destroyed. Previously it
> was 'moved' into the mem via SQL_DYNAMIC. But now you copy it and the
> original is not freed.
Thanks, fixed.


Diff:

diff --git a/src/box/sql/func.c b/src/box/sql/func.c
index 48d248568..de2bbb20e 100644
--- a/src/box/sql/func.c
+++ b/src/box/sql/func.c
@@ -861,23 +861,14 @@ func_printf(struct sql_context *ctx, int argc, struct Mem *argv)
 	struct PrintfArguments pargs;
 	struct StrAccum acc;
 	char *format = argv[0].z;
-	struct sql *db = sql_get();
-
 	pargs.nArg = argc - 1;
 	pargs.nUsed = 0;
-	pargs.apArg = sqlDbMallocRawNN(db, (argc - 1) * sizeof(*pargs.apArg));
-	if (pargs.apArg == NULL) {
-		ctx->is_aborted = true;
-		return;
-	}
-	for (int i = 1; i < argc; ++i)
-		pargs.apArg[i - 1] = &argv[i];
+	pargs.apArg = argv + 1;
+	struct sql *db = sql_get();
 	sqlStrAccumInit(&acc, db, 0, 0, db->aLimit[SQL_LIMIT_LENGTH]);
 	acc.printfFlags = SQL_PRINTF_SQLFUNC;
 	sqlXPrintf(&acc, format, &pargs);
-	sqlDbFree(db, pargs.apArg);
-	if (mem_copy_str(ctx->pOut, sqlStrAccumFinish(&acc), acc.nChar) != 0)
-		ctx->is_aborted = true;
+	mem_set_str_allocated(ctx->pOut, sqlStrAccumFinish(&acc), acc.nChar);
 }
 
 static const unsigned char *
diff --git a/src/box/sql/printf.c b/src/box/sql/printf.c
index b4ab0d0f9..5b61646e3 100644
--- a/src/box/sql/printf.c
+++ b/src/box/sql/printf.c
@@ -144,7 +144,7 @@ getIntArg(PrintfArguments * p)
 {
 	if (p->nArg <= p->nUsed)
 		return 0;
-	return mem_get_int_unsafe(p->apArg[p->nUsed++]);
+	return mem_get_int_unsafe(&p->apArg[p->nUsed++]);
 }
 
 static double
@@ -152,7 +152,7 @@ getDoubleArg(PrintfArguments * p)
 {
 	if (p->nArg <= p->nUsed)
 		return 0.0;
-	return mem_get_double_unsafe(p->apArg[p->nUsed++]);
+	return mem_get_double_unsafe(&p->apArg[p->nUsed++]);
 }
 
 static char *
@@ -160,7 +160,7 @@ getTextArg(PrintfArguments * p)
 {
 	if (p->nArg <= p->nUsed)
 		return 0;
-	struct Mem *mem = p->apArg[p->nUsed++];
+	struct Mem *mem = &p->apArg[p->nUsed++];
 	return (char *)mem_as_str0(mem);
 }
 
diff --git a/src/box/sql/sqlInt.h b/src/box/sql/sqlInt.h
index cfdf71f1f..9361775b1 100644
--- a/src/box/sql/sqlInt.h
+++ b/src/box/sql/sqlInt.h
@@ -2511,7 +2511,8 @@ int sqlIsNaN(double);
 struct PrintfArguments {
 	int nArg;		/* Total number of arguments */
 	int nUsed;		/* Number of arguments used so far */
-	sql_value **apArg;	/* The argument values */
+	/** The argument values. */
+	struct Mem *apArg;
 };
 
 void sqlVXPrintf(StrAccum *, const char *, va_list);


New patch:

commit 8d7ab164e7c69faf1a6f74b75deb769da0a0ee27
Author: Mergen Imeev <imeevma@gmail.com>
Date:   Tue Oct 5 18:25:55 2021 +0300

    sql: refactor PRINTF() function
    
    Part of #4145

diff --git a/src/box/sql/func.c b/src/box/sql/func.c
index 8eb3400bf..de2bbb20e 100644
--- a/src/box/sql/func.c
+++ b/src/box/sql/func.c
@@ -846,6 +846,31 @@ func_octet_length(struct sql_context *ctx, int argc, struct Mem *argv)
 	mem_set_uint(ctx->pOut, arg->n);
 }
 
+/** Implementation of the PRINTF() function. */
+static void
+func_printf(struct sql_context *ctx, int argc, struct Mem *argv)
+{
+	if (argc < 1 || mem_is_null(&argv[0]))
+		return;
+	if (argc == 1 || !mem_is_str(&argv[0])) {
+		struct Mem *mem = ctx->pOut;
+		if (mem_copy(mem, &argv[0]) != 0 || mem_to_str(mem) != 0)
+			ctx->is_aborted = true;
+		return;
+	}
+	struct PrintfArguments pargs;
+	struct StrAccum acc;
+	char *format = argv[0].z;
+	pargs.nArg = argc - 1;
+	pargs.nUsed = 0;
+	pargs.apArg = argv + 1;
+	struct sql *db = sql_get();
+	sqlStrAccumInit(&acc, db, 0, 0, db->aLimit[SQL_LIMIT_LENGTH]);
+	acc.printfFlags = SQL_PRINTF_SQLFUNC;
+	sqlXPrintf(&acc, format, &pargs);
+	mem_set_str_allocated(ctx->pOut, sqlStrAccumFinish(&acc), acc.nChar);
+}
+
 static const unsigned char *
 mem_as_ustr(struct Mem *mem)
 {
@@ -940,40 +965,6 @@ typeofFunc(struct sql_context *context, int argc, struct Mem *argv)
 	sql_result_text(context, z, -1, SQL_STATIC);
 }
 
-/*
- * Implementation of the printf() function.
- */
-static void
-printfFunc(struct sql_context *context, int argc, struct Mem *argv)
-{
-	PrintfArguments x;
-	StrAccum str;
-	const char *zFormat;
-	int n;
-	sql *db = sql_context_db_handle(context);
-
-	if (argc >= 1 && (zFormat = mem_as_str0(&argv[0])) != NULL) {
-		x.nArg = argc - 1;
-		x.nUsed = 0;
-		x.apArg = sqlDbMallocRawNN(sql_get(),
-					   (argc - 1) * sizeof(*x.apArg));
-		if (x.apArg == NULL) {
-			context->is_aborted = true;
-			return;
-		}
-		for (int i = 1; i < argc; ++i)
-			x.apArg[i - 1] = &argv[i];
-		sqlStrAccumInit(&str, db, 0, 0,
-				    db->aLimit[SQL_LIMIT_LENGTH]);
-		str.printfFlags = SQL_PRINTF_SQLFUNC;
-		sqlXPrintf(&str, zFormat, &x);
-		sqlDbFree(sql_get(), x.apArg);
-		n = str.nChar;
-		sql_result_text(context, sqlStrAccumFinish(&str), n,
-				    SQL_DYNAMIC);
-	}
-}
-
 /*
  * Implementation of the round() function
  */
@@ -1916,8 +1907,7 @@ static struct sql_func_definition definitions[] = {
 	 FIELD_TYPE_INTEGER, func_position_characters, NULL},
 	{"POSITION", 2, {FIELD_TYPE_VARBINARY, FIELD_TYPE_VARBINARY},
 	 FIELD_TYPE_INTEGER, func_position_octets, NULL},
-	{"PRINTF", -1, {FIELD_TYPE_ANY}, FIELD_TYPE_STRING, printfFunc, 
-	 NULL},
+	{"PRINTF", -1, {FIELD_TYPE_ANY}, FIELD_TYPE_STRING, func_printf, NULL},
 	{"QUOTE", 1, {FIELD_TYPE_ANY}, FIELD_TYPE_STRING, quoteFunc, NULL},
 	{"RANDOM", 0, {}, FIELD_TYPE_INTEGER, randomFunc, NULL},
 	{"RANDOMBLOB", 1, {FIELD_TYPE_INTEGER}, FIELD_TYPE_VARBINARY,
diff --git a/src/box/sql/printf.c b/src/box/sql/printf.c
index b4ab0d0f9..5b61646e3 100644
--- a/src/box/sql/printf.c
+++ b/src/box/sql/printf.c
@@ -144,7 +144,7 @@ getIntArg(PrintfArguments * p)
 {
 	if (p->nArg <= p->nUsed)
 		return 0;
-	return mem_get_int_unsafe(p->apArg[p->nUsed++]);
+	return mem_get_int_unsafe(&p->apArg[p->nUsed++]);
 }
 
 static double
@@ -152,7 +152,7 @@ getDoubleArg(PrintfArguments * p)
 {
 	if (p->nArg <= p->nUsed)
 		return 0.0;
-	return mem_get_double_unsafe(p->apArg[p->nUsed++]);
+	return mem_get_double_unsafe(&p->apArg[p->nUsed++]);
 }
 
 static char *
@@ -160,7 +160,7 @@ getTextArg(PrintfArguments * p)
 {
 	if (p->nArg <= p->nUsed)
 		return 0;
-	struct Mem *mem = p->apArg[p->nUsed++];
+	struct Mem *mem = &p->apArg[p->nUsed++];
 	return (char *)mem_as_str0(mem);
 }
 
diff --git a/src/box/sql/sqlInt.h b/src/box/sql/sqlInt.h
index cfdf71f1f..9361775b1 100644
--- a/src/box/sql/sqlInt.h
+++ b/src/box/sql/sqlInt.h
@@ -2511,7 +2511,8 @@ int sqlIsNaN(double);
 struct PrintfArguments {
 	int nArg;		/* Total number of arguments */
 	int nUsed;		/* Number of arguments used so far */
-	sql_value **apArg;	/* The argument values */
+	/** The argument values. */
+	struct Mem *apArg;
 };
 
 void sqlVXPrintf(StrAccum *, const char *, va_list);