Bugfix: skip NULL fields when reading from MySQL

sociomantic-tsunami · May 10, 2017 · db121fe · db121fe
1 parent 2fbfe3b
commit db121fe
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Showing 4 changed files with 19 additions and 4 deletions.
diff --git a/libdrizzle/field.cc b/libdrizzle/field.cc
@@ -402,9 +402,21 @@ drizzle_return_t drizzle_state_binary_field_read(drizzle_st *con)
 {
   drizzle_return_t ret;
 
-  switch(con->result->column_buffer[con->result->field_current].type)
+  /* Skip NULL fields */
+  while (con->result->null_bitmap[(con->result->field_current_read + 2) / 8] &
+         (1 << ((con->result->field_current_read + 2) % 8)))
+  {
+    con->result->field_current_read++;
+  }
+
+  switch(con->result->column_buffer[con->result->field_current_read].type)
   {
     case DRIZZLE_COLUMN_TYPE_NULL:
+      /* This should not happen since NULL fields are masked by `null_bitmap`, but cover it anyway */
+      drizzle_set_error(con, __func__,
+        "Unexpected column type: DRIZZLE_COLUMN_TYPE_NULL");
+      con->result->field_size= 0;
+      return DRIZZLE_RETURN_UNEXPECTED_DATA;
       break;
     case DRIZZLE_COLUMN_TYPE_TINY:
       con->result->field_size= 1;
@@ -462,6 +474,7 @@ drizzle_return_t drizzle_state_binary_field_read(drizzle_st *con)
   con->result->field_total= con->result->field_size;
 
   con->result->field_current++;
+  con->result->field_current_read++;
   con->pop_state();
   return DRIZZLE_RETURN_OK;
 }
diff --git a/libdrizzle/result.h b/libdrizzle/result.h
@@ -65,6 +65,7 @@ struct drizzle_result_st
   uint64_t row_current;
 
   uint16_t field_current;         /* field index */
+  uint16_t field_current_read;    /* index of the field currently being read */
   uint64_t field_total;           /* total length of the field currently being read */
   uint64_t field_offset;          /* offset within field of most recently read field fragment (0 if first/only fragment) */
   uint32_t field_size;            /* size of most recently read field value or fragment of field value; max 2^24 */
@@ -102,6 +103,7 @@ struct drizzle_result_st
     row_count(0),
     row_current(0),
     field_current(0),
+    field_current_read(0),
     field_total(0),
     field_offset(0),
     field_size(0),

diff --git a/libdrizzle/row.cc b/libdrizzle/row.cc
@@ -303,6 +303,7 @@ drizzle_return_t drizzle_state_row_read(drizzle_st *con)
     con->result->row_count++;
     con->result->row_current++;
     con->result->field_current= 0;
+    con->result->field_current_read= 0;
   }
 
   con->pop_state();

diff --git a/libdrizzle/statement.cc b/libdrizzle/statement.cc
@@ -392,7 +392,6 @@ drizzle_return_t drizzle_stmt_fetch(drizzle_stmt_st *stmt)
   drizzle_return_t ret= DRIZZLE_RETURN_OK;
   uint16_t column_counter= 0, current_column= 0;
   drizzle_row_t row;
-  drizzle_column_st *column;
 
   if (stmt == NULL)
   {
@@ -422,11 +421,12 @@ drizzle_return_t drizzle_stmt_fetch(drizzle_stmt_st *stmt)
   {
     return DRIZZLE_RETURN_ROW_END;
   }
-  drizzle_column_seek(stmt->execute_result, 0);
 
   for (column_counter = 0; column_counter < stmt->execute_result->column_count; column_counter++)
   {
     drizzle_bind_st *param= &stmt->result_params[column_counter];
+    drizzle_column_st *column= drizzle_column_index(stmt->execute_result, column_counter);
+
     /* if this row is null in the result bitmap, skip first 2 bits */
     if (stmt->execute_result->null_bitmap[(column_counter+2)/8] & (1 << ((column_counter+2) % 8)))
     {
@@ -439,7 +439,6 @@ drizzle_return_t drizzle_stmt_fetch(drizzle_stmt_st *stmt)
       uint16_t short_data;
       uint32_t long_data;
       uint64_t longlong_data;
-      column= drizzle_column_next(stmt->execute_result);
       param->type= column->type;
       param->options.is_null= false;
       param->length= stmt->execute_result->field_sizes[current_column];