port code to psycopg3

src/nominatim_db/db/utils.py

@@ -7,14 +7,13 @@
 """
 Helper functions for handling DB accesses.
 """
-from typing import IO, Optional, Union, Any, Iterable
+from typing import IO, Optional, Union
 import subprocess
 import logging
 import gzip
-import io
 from pathlib import Path
 
-from .connection import get_pg_env, Cursor
+from .connection import get_pg_env
 from ..errors import UsageError
 
 LOG = logging.getLogger()
@@ -72,58 +71,3 @@ def execute_file(dsn: str, fname: Path,
 
     if ret != 0 or remain > 0:
         raise UsageError("Failed to execute SQL file.")
-
-
-# List of characters that need to be quoted for the copy command.
-_SQL_TRANSLATION = {ord('\\'): '\\\\',
-                    ord('\t'): '\\t',
-                    ord('\n'): '\\n'}
-
-
-class CopyBuffer:
-    """ Data collector for the copy_from command.
-    """
-
-    def __init__(self) -> None:
-        self.buffer = io.StringIO()
-
-
-    def __enter__(self) -> 'CopyBuffer':
-        return self
-
-
-    def size(self) -> int:
-        """ Return the number of bytes the buffer currently contains.
-        """
-        return self.buffer.tell()
-
-    def __exit__(self, exc_type: Any, exc_value: Any, traceback: Any) -> None:
-        if self.buffer is not None:
-            self.buffer.close()
-
-
-    def add(self, *data: Any) -> None:
-        """ Add another row of data to the copy buffer.
-        """
-        first = True
-        for column in data:
-            if first:
-                first = False
-            else:
-                self.buffer.write('\t')
-            if column is None:
-                self.buffer.write('\\N')
-            else:
-                self.buffer.write(str(column).translate(_SQL_TRANSLATION))
-        self.buffer.write('\n')
-
-
-    def copy_out(self, cur: Cursor, table: str, columns: Optional[Iterable[str]] = None) -> None:
-        """ Copy all collected data into the given table.
-
-            The buffer is empty and reusable after this operation.
-        """
-        if self.buffer.tell() > 0:
-            self.buffer.seek(0)
-            cur.copy_from(self.buffer, table, columns=columns)
-            self.buffer = io.StringIO()