[Tarantool-patches] [PATCH v5 29/52] sql: introduce mem_set_bin_*() functions

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

Thank you for the review! My answers and new patch below.


On 30.03.2021 02:05, Vladislav Shpilevoy wrote:
> Thanks for the patch!
>
> See 2 comments below.
>
>> diff --git a/src/box/sql/mem.c b/src/box/sql/mem.c
>> index 59a378e1b..5ee49cdca 100644
>> --- a/src/box/sql/mem.c
>> +++ b/src/box/sql/mem.c
>> @@ -410,6 +410,61 @@ mem_copy_string0(struct Mem *mem, const char *value)
>>    return 0;
>>  }
>>  
>> +static inline void
>> +mem_set_const_bin(struct Mem *mem, char *value, uint32_t size, int alloc_type)
>> +{
>> +  assert((alloc_type & (MEM_Static | MEM_Ephem)) != 0);
>> +  mem_clear(mem);
>> +  mem->z = value;
>> +  mem->n = size;
>> +  mem->flags = MEM_Blob | alloc_type;
>> +  mem->field_type = FIELD_TYPE_VARBINARY;
>> +}
>> +
>> +static inline void
>> +mem_set_dyn_bin(struct Mem *mem, char *value, uint32_t size, int alloc_type)
>> +{
>> +  assert((mem->flags & MEM_Dyn) == 0 || value != mem->z);
>> +  assert(mem->szMalloc == 0 || value != mem->zMalloc);
>> +  assert(alloc_type == MEM_Dyn || alloc_type == 0);
>> +  mem_destroy(mem);
>
> 1. Why is it destroy here and clear above?
>
There is a rule which I cannot understand - it says that MEM should contain
either given allocated memory + sql_free() (MEM_Dyn) or "self-allocated" memory
(which may be not self-allocated actually, but still). I see no reason for this,
but I decided to leave it as it is for now. So, in case we set MEM_Dyn or
allocated type (when MEM_Static, MEM_Ephem and MEM_Dyn unset) MEM have to free
all memory. This is why we use destroy here. In case of MEM_Ephem or MEM_Static
we only should free memory if it is of MEM_Dyn type. So that is why we use
clear() there.

>> +  mem->z = value;
>> +  mem->n = size;
>> +  mem->flags = MEM_Blob | alloc_type;
>> +  mem->field_type = FIELD_TYPE_VARBINARY;
>> +  if (alloc_type == MEM_Dyn) {
>> +    mem->xDel = sql_free;
>> +  } else {
>> +    mem->xDel = NULL;
>> +    mem->zMalloc = mem->z;
>> +    mem->szMalloc = sqlDbMallocSize(mem->db, mem->zMalloc);
>> +  }
>> +}
>> diff --git a/src/box/sql/vdbeapi.c b/src/box/sql/vdbeapi.c
>> index 5b5e5b0c8..0e51e4809 100644
>> --- a/src/box/sql/vdbeapi.c
>> +++ b/src/box/sql/vdbeapi.c
>> @@ -183,7 +182,13 @@ sql_result_blob(sql_context * pCtx,
>>      )
>>  {
>>    assert(n >= 0);
>> -  if (sqlVdbeMemSetStr(pCtx->pOut, z, n, 0, xDel) != 0)
>> +  if (xDel == SQL_STATIC)
>> +    mem_set_static_binary(pCtx->pOut, (char *)z, n);
>> +  else if (xDel == SQL_DYNAMIC)
>> +    mem_set_allocated_binary(pCtx->pOut, (char *)z, n);
>> +  else if (xDel != SQL_TRANSIENT)
>> +    mem_set_dynamic_binary(pCtx->pOut, (char *)z, n);
>> +  else if (sqlVdbeMemSetStr(pCtx->pOut, z, n, 0, xDel) != 0)
>>      pCtx->is_aborted = true;
>
> 2. It seems to me you need to add a generic mem_set_binary which would
> take the xdel argument. Repeating this tree of ifs in each usage place
> is not any better. The same for the string API.
I think the problem here is mostly with the way built-in functions returns their
result. Don't you think that it is better to change sql_result_*() instead of
adding of a generic mem_set_binary() function?

About bindText() - I think it is better to move sql_bind_column() to
sql/vdbeapi.c and inline such functions as bindText(), sql_bind_double(), etc.
This is the only place they are used, after all.

Still, I didn't do any of these changes. I plan to rework built-in functions
later, along with removing them from _func. As for sql_bind_column() - I just
not sure that this should be done in this patch-set. No problem to add one more
patch to the set, though. What do you think?


New patch:

commit 67af1300324e2548ffa9234e762cdc473ba88e19
Author: Mergen Imeev <imeevma@gmail.com>
Date:   Tue Mar 16 10:17:33 2021 +0300

    sql: introduce mem_set_bin_*() functions
    
    This patch introduces set of mem_set_bin_*() functions. These functions
    clears MEM and sets it to given binary value. Degree of clearing and
    type of allocation of the binary value is determined by the function
    used.
    
    Part of #5818

diff --git a/src/box/sql/mem.c b/src/box/sql/mem.c
index 045c44e8f..2622cdd82 100644
--- a/src/box/sql/mem.c
+++ b/src/box/sql/mem.c
@@ -422,6 +422,61 @@ mem_copy_str0(struct Mem *mem, const char *value)
  return 0;
 }
 
+static inline void
+set_bin_const(struct Mem *mem, char *value, uint32_t size, int alloc_type)
+{
+ assert((alloc_type & (MEM_Static | MEM_Ephem)) != 0);
+ mem_clear(mem);
+ mem->z = value;
+ mem->n = size;
+ mem->flags = MEM_Blob | alloc_type;
+ mem->field_type = FIELD_TYPE_VARBINARY;
+}
+
+static inline void
+set_bin_dynamic(struct Mem *mem, char *value, uint32_t size, int alloc_type)
+{
+ assert((mem->flags & MEM_Dyn) == 0 || value != mem->z);
+ assert(mem->szMalloc == 0 || value != mem->zMalloc);
+ assert(alloc_type == MEM_Dyn || alloc_type == 0);
+ mem_destroy(mem);
+ mem->z = value;
+ mem->n = size;
+ mem->flags = MEM_Blob | alloc_type;
+ mem->field_type = FIELD_TYPE_VARBINARY;
+ if (alloc_type == MEM_Dyn) {
+   mem->xDel = sql_free;
+ } else {
+   mem->xDel = NULL;
+   mem->zMalloc = mem->z;
+   mem->szMalloc = sqlDbMallocSize(mem->db, mem->zMalloc);
+ }
+}
+
+void
+mem_set_bin_ephemeral(struct Mem *mem, char *value, uint32_t size)
+{
+ set_bin_const(mem, value, size, MEM_Ephem);
+}
+
+void
+mem_set_bin_static(struct Mem *mem, char *value, uint32_t size)
+{
+ set_bin_const(mem, value, size, MEM_Static);
+}
+
+void
+mem_set_bin_dynamic(struct Mem *mem, char *value, uint32_t size)
+{
+ set_bin_dynamic(mem, value, size, MEM_Dyn);
+}
+
+void
+mem_set_bin_allocated(struct Mem *mem, char *value, uint32_t size)
+{
+ set_bin_dynamic(mem, value, size, 0);
+}
+
 int
 mem_copy(struct Mem *to, const struct Mem *from)
 {
@@ -2547,19 +2602,6 @@ mem_is_type_compatible(struct Mem *mem, enum field_type type)
  return field_mp_plain_type_is_compatible(type, mp_type, true);
 }
 
-/* Allocate memory for internal VDBE structure on region. */
-int
-vdbe_mem_alloc_blob_region(struct Mem *vdbe_mem, uint32_t size)
-{
- vdbe_mem->n = size;
- vdbe_mem->z = region_alloc(&fiber()->gc, size);
- if (vdbe_mem->z == NULL)
-   return -1;
- vdbe_mem->flags = MEM_Ephem | MEM_Blob;
- assert(sqlVdbeCheckMemInvariants(vdbe_mem));
- return 0;
-}
-
 int
 sql_vdbemem_finalize(struct Mem *mem, struct func *func)
 {
diff --git a/src/box/sql/mem.h b/src/box/sql/mem.h
index d03651192..532860ff7 100644
--- a/src/box/sql/mem.h
+++ b/src/box/sql/mem.h
@@ -246,6 +246,34 @@ mem_copy_str(struct Mem *mem, const char *value, uint32_t len);
 int
 mem_copy_str0(struct Mem *mem, const char *value);
 
+/**
+ * Clear MEM and set it to VARBINARY. The binary value belongs to another
+ * object.
+ */
+void
+mem_set_bin_ephemeral(struct Mem *mem, char *value, uint32_t size);
+
+/** Clear MEM and set it to VARBINARY. The binary value is static. */
+void
+mem_set_bin_static(struct Mem *mem, char *value, uint32_t size);
+
+/**
+ * Clear MEM and set it to VARBINARY. The binary value was allocated by another
+ * object and passed to MEM. MEMs with this allocation type must free given
+ * memory whenever the MEM changes.
+ */
+void
+mem_set_bin_dynamic(struct Mem *mem, char *value, uint32_t size);
+
+/**
+ * Clear MEM and set it to VARBINARY. The binary value was allocated by another
+ * object and passed to MEM. MEMs with this allocation type only deallocate the
+ * string on destruction. Also, the memory may be reallocated if MEM is set to a
+ * different value of this allocation type.
+ */
+void
+mem_set_bin_allocated(struct Mem *mem, char *value, uint32_t size);
+
 /**
  * Copy content of MEM from one MEM to another. In case source MEM contains
  * string or binary and allocation type is not STATIC, this value is copied to
@@ -606,9 +634,6 @@ mem_is_type_compatible(struct Mem *mem, enum field_type type);
 
 /** MEM manipulate functions. */
 
-int
-vdbe_mem_alloc_blob_region(struct Mem *vdbe_mem, uint32_t size);
-
 /**
  * Memory cell mem contains the context of an aggregate function.
  * This routine calls the finalize method for that function. The
diff --git a/src/box/sql/vdbe.c b/src/box/sql/vdbe.c
index 943179c55..85fb7a26d 100644
--- a/src/box/sql/vdbe.c
+++ b/src/box/sql/vdbe.c
@@ -886,8 +886,15 @@ case OP_Null: {           /* out2 */
 case OP_Blob: {                /* out2 */
  assert(pOp->p1 <= SQL_MAX_LENGTH);
  pOut = vdbe_prepare_null_out(p, pOp->p2);
- sqlVdbeMemSetStr(pOut, pOp->p4.z, pOp->p1, 0, 0);
- if (pOp->p3!=0) {
+ if (pOp->p3 == 0) {
+   /*
+    * TODO: It is possible that vabinary should be stored as
+    * ephemeral or static depending on value. There is no way to
+    * determine right now, so it is stored as static.
+    */
+   mem_set_bin_static(pOut, pOp->p4.z, pOp->p1);
+ } else {
+   sqlVdbeMemSetStr(pOut, pOp->p4.z, pOp->p1, 0, 0);
    pOut->flags |= MEM_Subtype;
    pOut->subtype = pOp->p3;
  }
@@ -2201,9 +2208,7 @@ case OP_MakeRecord: {
     * sure previously allocated memory has gone.
     */
    mem_destroy(pOut);
-   pOut->flags = MEM_Blob | MEM_Ephem;
-   pOut->n = tuple_size;
-   pOut->z = tuple;
+   mem_set_bin_ephemeral(pOut, tuple, tuple_size);
  }
  assert(sqlVdbeCheckMemInvariants(pOut));
  assert(pOp->p3>0 && pOp->p3<=(p->nMem+1 - p->nCursor));
@@ -3286,9 +3291,14 @@ case OP_RowData: {
  }
  testcase( n==0);
 
- if (vdbe_mem_alloc_blob_region(pOut, n) != 0)
+ char *buf = region_alloc(&fiber()->gc, n);
+ if (buf == NULL) {
+   diag_set(OutOfMemory, n, "region_alloc", "buf");
    goto abort_due_to_error;
- sqlCursorPayload(pCrsr, 0, n, pOut->z);
+ }
+ sqlCursorPayload(pCrsr, 0, n, buf);
+ mem_set_bin_ephemeral(pOut, buf, n);
+ assert(sqlVdbeCheckMemInvariants(pOut));
  UPDATE_MAX_BLOBSIZE(pOut);
  REGISTER_TRACE(p, pOp->p2, pOut);
  break;
diff --git a/src/box/sql/vdbeapi.c b/src/box/sql/vdbeapi.c
index ee095f36e..8c7a0b6cd 100644
--- a/src/box/sql/vdbeapi.c
+++ b/src/box/sql/vdbeapi.c
@@ -111,9 +111,8 @@ sql_metadata_is_full()
  * The following routines are used by user-defined functions to specify
  * the function result.
  *
- * The setStrOrError() function calls sqlVdbeMemSetStr() to store the
- * result as a string or blob but if the string or blob is too large, it
- * then sets the error code.
+ * The setStrOrError() function sets the result as a string or blob but
+ * if the string or blob is too large, it then sets the error code.
  *
  * The invokeValueDestructor(P,X) routine invokes destructor function X()
  * on value P is not going to be used and need to be destroyed.
@@ -183,7 +182,13 @@ sql_result_blob(sql_context * pCtx,
     )
 {
  assert(n >= 0);
- if (sqlVdbeMemSetStr(pCtx->pOut, z, n, 0, xDel) != 0)
+ if (xDel == SQL_STATIC)
+   mem_set_bin_static(pCtx->pOut, (char *)z, n);
+ else if (xDel == SQL_DYNAMIC)
+   mem_set_bin_allocated(pCtx->pOut, (char *)z, n);
+ else if (xDel != SQL_TRANSIENT)
+   mem_set_bin_dynamic(pCtx->pOut, (char *)z, n);
+ else if (sqlVdbeMemSetStr(pCtx->pOut, z, n, 0, xDel) != 0)
    pCtx->is_aborted = true;
 }
 
@@ -832,7 +837,13 @@ sql_bind_blob(sql_stmt * pStmt,
  if (zData == NULL)
    return 0;
  struct Mem *var = &p->aVar[i - 1];
- if (sqlVdbeMemSetStr(var, zData, nData, 0, xDel) != 0)
+ if (xDel == SQL_STATIC)
+   mem_set_bin_static(var, (char *)zData, nData);
+ else if (xDel == SQL_DYNAMIC)
+   mem_set_bin_allocated(var, (char *)zData, nData);
+ else if (xDel != SQL_TRANSIENT)
+   mem_set_bin_dynamic(var, (char *)zData, nData);
+ else if (sqlVdbeMemSetStr(var, zData, nData, 0, xDel) != 0)
    return -1;
  return sql_bind_type(p, i, "varbinary");
 }