LOB fixes for 18c database.

Author: anthony-tuininga

src/oracledb/impl/thin/buffer.pyx

@@ -899,6 +899,23 @@ cdef class ReadBuffer:
             if is_negative:
                 value[0] = -value[0]
 
+    cdef int read_sb8(self, int64_t *value) except -1:
+        """
+        Reads a signed 64-bit integer from the buffer.
+        """
+        cdef:
+            const char_type *ptr
+            bint is_negative
+            uint8_t length
+        self._get_int_length_and_sign(&length, &is_negative, 8)
+        if length == 0:
+            value[0] = 0
+        else:
+            ptr = self._get_raw(length)
+            value[0] = self._unpack_int(ptr, length)
+            if is_negative:
+                value[0] = -value[0]
+
     cdef object read_str(self, int csfrm):
         """
         Reads a string from the buffer.

src/oracledb/impl/thin/constants.pxi

@@ -461,6 +461,9 @@ DEF TNS_LOB_TEMP_POS = 7
 DEF TNS_LOB_TEMP_VALUE = 0x01
 DEF TNS_LOB_ABSTRACT_VALUE = 0x40
 
+# other LOB constants
+DEF TNS_LOB_OPEN_READ_WRITE = 2
+
 # end-to-end metrics
 DEF TNS_END_TO_END_ACTION = 0x0010
 DEF TNS_END_TO_END_CLIENT_IDENTIFIER = 0x0001

src/oracledb/impl/thin/lob.pyx

@@ -122,6 +122,8 @@ cdef class ThinLobImpl(BaseLobImpl):
         message = self._conn_impl._create_message(LobOpMessage)
         message.operation = TNS_LOB_OP_OPEN
         message.source_lob_impl = self
+        message.amount = TNS_LOB_OPEN_READ_WRITE
+        message.send_amount = True
         self._conn_impl._protocol._process_single_message(message)
 
     def read(self, uint64_t offset, uint64_t amount):

src/oracledb/impl/thin/messages.pyx

@@ -1857,7 +1857,7 @@ cdef class LobOpMessage(Message):
         ThinLobImpl dest_lob_impl
         uint64_t source_offset
         uint64_t dest_offset
-        uint64_t amount
+        int64_t amount
         bint send_amount
         bint bool_flag
         object data
@@ -1903,7 +1903,7 @@ cdef class LobOpMessage(Message):
         if self.operation == TNS_LOB_OP_CREATE_TEMP:
             buf.skip_ub2()                  # skip character set
         if self.send_amount:
-            buf.read_ub8(&self.amount)
+            buf.read_sb8(&self.amount)
         if self.operation == TNS_LOB_OP_CREATE_TEMP \
                 or self.operation == TNS_LOB_OP_IS_OPEN:
             buf.read_ub2(&temp16)           # flag
@@ -1930,19 +1930,15 @@ cdef class LobOpMessage(Message):
             buf.write_uint8(1)              # pointer (character set)
         else:
             buf.write_uint8(0)              # pointer (character set)
-        buf.write_uint8(0)                  # pointer (amount)
+        buf.write_uint8(0)                  # pointer (short amount)
         if self.operation == TNS_LOB_OP_CREATE_TEMP \
                 or self.operation == TNS_LOB_OP_IS_OPEN:
             buf.write_uint8(1)              # pointer (NULL LOB)
         else:
             buf.write_uint8(0)              # pointer (NULL LOB)
         buf.write_ub4(self.operation)
-        if self.operation == TNS_LOB_OP_CREATE_TEMP:
-            buf.write_uint8(1)              # pointer (SCN array)
-            buf.write_ub4(1)                # SCN array length
-        else:
-            buf.write_uint8(0)              # pointer (SCN array)
-            buf.write_ub4(0)                # SCN array length
+        buf.write_uint8(0)                  # pointer (SCN array)
+        buf.write_uint8(0)                  # SCN array length
         buf.write_ub8(self.source_offset)
         buf.write_ub8(self.dest_offset)
         if self.send_amount:
@@ -1960,13 +1956,11 @@ cdef class LobOpMessage(Message):
                 buf.write_ub4(TNS_CHARSET_UTF16)
             else:
                 buf.write_ub4(TNS_CHARSET_UTF8)
-        if self.send_amount:
-            buf.write_ub8(self.amount)
         if self.data is not None:
             buf.write_uint8(TNS_MSG_TYPE_LOB_DATA)
             buf.write_bytes_chunked(self.data)
-        if self.operation == TNS_LOB_OP_CREATE_TEMP:
-            buf.write_ub4(0)                # SCN array element
+        if self.send_amount:
+            buf.write_ub8(self.amount)      # LOB amount
 
 
 @cython.final