Replace several uses of str(path) with fspath(path)

Helps make it more explicit. Did not do this to tests because use of paths
is more involved there.

src/ocrmypdf/helpers.py

@@ -29,8 +29,8 @@ def re_symlink(input_file, soft_link_name, log=None):
     """
     Helper function: relinks soft symbolic link if necessary
     """
-    input_file = str(input_file)  # For Py3.5
-    soft_link_name = str(soft_link_name)
+    input_file = fspath(input_file)  # For Py3.5
+    soft_link_name = fspath(soft_link_name)
     if log is None:
         prdebug = partial(print, file=sys.stderr)
     else:
@@ -108,14 +108,14 @@ def is_file_writable(test_file):
         # defaults to strict=False. This implements strict=False like behavior
         # for Python 3.5.
         if sys.version_info[0:2] <= (3, 5):
-            p = Path(os.path.realpath(str(p)))
+            p = Path(os.path.realpath(fspath(p)))
         else:
             p = p.resolve(strict=False)
 
     # p.is_file() throws an exception in some cases
     if p.exists() and p.is_file():
         return os.access(
-            str(p), os.W_OK,
+            fspath(p), os.W_OK,
             effective_ids=(os.access in os.supports_effective_ids))
     else:
         try:

src/ocrmypdf/optimize.py

@@ -39,7 +39,7 @@ PNG_QUALITY = (65, 75)
 
 
 def img_name(root, xref, ext):
-    return str(root / '{:08d}{}'.format(xref, ext))
+    return fspath(root / '{:08d}{}'.format(xref, ext))
 
 
 def png_name(root, xref):
@@ -193,7 +193,7 @@ def convert_to_jbig2(pike, jbig2_groups, root, log, options):
             prefix = 'group{:08d}'.format(group)
             future = executor.submit(
                 jbig2enc.convert_group,
-                cwd=str(root),
+                cwd=fspath(root),
                 infiles=(img_name(root, xref, ext) for xref, ext in xref_exts),
                 out_prefix=prefix
             )
@@ -229,8 +229,8 @@ def transcode_jpegs(pike, jpegs, root, log, options):
         # DEBUG:PIL.Image:Error closing: 'NoneType' object has no attribute
         # 'close'.  Seems to be mostly harmless
         # https://github.com/python-pillow/Pillow/issues/1144
-        with Image.open(str(in_jpg)) as im:
-            im.save(str(opt_jpg),
+        with Image.open(fspath(in_jpg)) as im:
+            im.save(fspath(opt_jpg),
                     optimize=True,
                     quality=JPEG_QUALITY)
         if opt_jpg.stat().st_size > in_jpg.stat().st_size:

src/ocrmypdf/pdfinfo.py

@@ -575,7 +575,7 @@ def _pdf_get_pageinfo(pdf, pageno: int, infile):
 
     page = pdf.pages[pageno]
 
-    pageinfo['textinfo'] = _page_get_textblocks(str(infile), pageno)
+    pageinfo['textinfo'] = _page_get_textblocks(fspath(infile), pageno)
 
     mediabox = [Decimal(d) for d in page.MediaBox.as_list()]
     width_pt = mediabox[2] - mediabox[0]