X-Git-Url: https://git.openstreetmap.org/nominatim.git/blobdiff_plain/1e9f37ab82db1758235bedf83c659693f4ca6c3e..a7a920a9a5b55bf4290b184f05898a8589c95b40:/nominatim/db/utils.py

diff --git a/nominatim/db/utils.py b/nominatim/db/utils.py
index bb7faa25..57048da3 100644
--- a/nominatim/db/utils.py
+++ b/nominatim/db/utils.py
@@ -1,17 +1,27 @@
+# SPDX-License-Identifier: GPL-2.0-only
+#
+# This file is part of Nominatim. (https://nominatim.org)
+#
+# Copyright (C) 2022 by the Nominatim developer community.
+# For a full list of authors see the git log.
 """
 Helper functions for handling DB accesses.
 """
+from typing import IO, Optional, Union, Any, Iterable
 import subprocess
 import logging
 import gzip
 import io
+from pathlib import Path
 
-from nominatim.db.connection import get_pg_env
+from nominatim.db.connection import get_pg_env, Cursor
 from nominatim.errors import UsageError
 
 LOG = logging.getLogger()
 
-def _pipe_to_proc(proc, fdesc):
+def _pipe_to_proc(proc: 'subprocess.Popen[bytes]',
+                  fdesc: Union[IO[bytes], gzip.GzipFile]) -> int:
+    assert proc.stdin is not None
     chunk = fdesc.read(2048)
     while chunk and proc.poll() is None:
         try:
@@ -22,7 +32,10 @@ def _pipe_to_proc(proc, fdesc):
 
     return len(chunk)
 
-def execute_file(dsn, fname, ignore_errors=False, pre_code=None, post_code=None):
+def execute_file(dsn: str, fname: Path,
+                 ignore_errors: bool = False,
+                 pre_code: Optional[str] = None,
+                 post_code: Optional[str] = None) -> None:
     """ Read an SQL file and run its contents against the given database
         using psql. Use `pre_code` and `post_code` to run extra commands
         before or after executing the file. The commands are run within the
@@ -34,56 +47,62 @@ def execute_file(dsn, fname, ignore_errors=False, pre_code=None, post_code=None)
         cmd.extend(('-v', 'ON_ERROR_STOP=1'))
     if not LOG.isEnabledFor(logging.INFO):
         cmd.append('--quiet')
-    proc = subprocess.Popen(cmd, env=get_pg_env(dsn), stdin=subprocess.PIPE)
 
-    try:
-        if not LOG.isEnabledFor(logging.INFO):
-            proc.stdin.write('set client_min_messages to WARNING;'.encode('utf-8'))
+    with subprocess.Popen(cmd, env=get_pg_env(dsn), stdin=subprocess.PIPE) as proc:
+        assert proc.stdin is not None
+        try:
+            if not LOG.isEnabledFor(logging.INFO):
+                proc.stdin.write('set client_min_messages to WARNING;'.encode('utf-8'))
 
-        if pre_code:
-            proc.stdin.write((pre_code + ';').encode('utf-8'))
+            if pre_code:
+                proc.stdin.write((pre_code + ';').encode('utf-8'))
 
-        if fname.suffix == '.gz':
-            with gzip.open(str(fname), 'rb') as fdesc:
-                remain = _pipe_to_proc(proc, fdesc)
-        else:
-            with fname.open('rb') as fdesc:
-                remain = _pipe_to_proc(proc, fdesc)
+            if fname.suffix == '.gz':
+                with gzip.open(str(fname), 'rb') as fdesc:
+                    remain = _pipe_to_proc(proc, fdesc)
+            else:
+                with fname.open('rb') as fdesc:
+                    remain = _pipe_to_proc(proc, fdesc)
 
-        if remain == 0 and post_code:
-            proc.stdin.write((';' + post_code).encode('utf-8'))
-    finally:
-        proc.stdin.close()
-        ret = proc.wait()
+            if remain == 0 and post_code:
+                proc.stdin.write((';' + post_code).encode('utf-8'))
+        finally:
+            proc.stdin.close()
+            ret = proc.wait()
 
     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(u'\\'): u'\\\\',
-                    ord(u'\t'): u'\\t',
-                    ord(u'\n'): u'\\n'}
+_SQL_TRANSLATION = {ord('\\'): '\\\\',
+                    ord('\t'): '\\t',
+                    ord('\n'): '\\n'}
 
 
 class CopyBuffer:
     """ Data collector for the copy_from command.
     """
 
-    def __init__(self):
+    def __init__(self) -> None:
         self.buffer = io.StringIO()
 
 
-    def __enter__(self):
+    def __enter__(self) -> 'CopyBuffer':
         return self
 
 
-    def __exit__(self, exc_type, exc_value, traceback):
+    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):
+    def add(self, *data: Any) -> None:
         """ Add another row of data to the copy buffer.
         """
         first = True
@@ -99,9 +118,12 @@ class CopyBuffer:
         self.buffer.write('\n')
 
 
-    def copy_out(self, cur, table, columns=None):
+    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()