More explicit closing of resources

src/calibre/db/fts/text.py

@@ -70,6 +70,7 @@ def pdftotext(path):
     cmd = [PDFTOTEXT] + '-enc UTF-8 -nodiag -eol unix'.split() + [os.path.basename(path), '-']
     p = popen(cmd, cwd=os.path.dirname(path), stdout=subprocess.PIPE, stdin=subprocess.DEVNULL)
     raw = p.stdout.read()
+    p.stdout.close()
     if p.wait() != 0:
         return ''
     return clean_ascii_chars(raw).decode('utf-8', 'replace')

src/calibre/ebooks/metadata/utils.py

@@ -32,9 +32,14 @@ def parse_opf_version(raw):
 
 def parse_opf(stream_or_path):
     stream = stream_or_path
-    if not hasattr(stream, 'read'):
+    needs_close = not hasattr(stream, 'read')
+    if needs_close:
         stream = open(stream, 'rb')
-    raw = stream.read()
+    try:
+        raw = stream.read()
+    finally:
+        if needs_close:
+            stream.close()
     if not raw:
         raise ValueError('Empty file: '+getattr(stream, 'name', 'stream'))
     raw, encoding = xml_to_unicode(raw, strip_encoding_pats=True, resolve_entities=True, assume_utf8=True)

src/calibre/library/database2.py

@@ -1478,7 +1478,7 @@ class LibraryDatabase2(LibraryDatabase, SchemaUpgrade, CustomColumns):
                     f = open(path, 'rb')
                 except OSError:
                     time.sleep(0.2)
-                f = open(path, 'rb')
+                    f = open(path, 'rb')
                 with f:
                     if hasattr(dest, 'write'):
                         shutil.copyfileobj(f, dest)