Support generating docs on Windows.

We use `os.path.join` to build URLs from relative paths in a number of places. This doesn't work on Windows, where the path separator is different. Rather than depending on an external package like `urlpath`, I've replaced `os.path.join` with `posixpath.join` and where needed, used os-split and posix-join to re-encode.

Windows doesn't throw `OSError` on missing files either, so fixed that too.

This *should* fix tensorflow#53216. Tested with `generate2` on my Windows box.

PiperOrigin-RevId: 419944483

Author: markmcd

tools/tensorflow_docs/api_generator/generate_lib.py

@@ -871,11 +871,7 @@ def build(self, output_dir):
           str(work_py_dir / self._short_name.replace('.', '/') /
               '_api_cache.json'))
 
-    try:
-      os.makedirs(output_dir)
-    except OSError as e:
-      if e.strerror != 'File exists':
-        raise
+    os.makedirs(output_dir, exist_ok=True)
 
     # Typical results are something like:
     #

tools/tensorflow_docs/api_generator/parser.py

@@ -15,14 +15,14 @@
 # ==============================================================================
 """Turn Python docstrings into Markdown for TensorFlow documentation."""
 
-import ast
 import collections
 import dataclasses
 import enum
 import html
 import inspect
 import itertools
 import os
+import posixpath
 import pprint
 import re
 import textwrap
@@ -98,7 +98,7 @@ def documentation_path(full_name, is_fragment=False):
   if is_fragment:
     parts, fragment = parts[:-1], parts[-1]
 
-  result = os.path.join(*parts) + '.md'
+  result = posixpath.join(*parts) + '.md'
 
   if is_fragment:
     result = result + '#' + fragment
@@ -1437,6 +1437,8 @@ def docs_for_object(
 
   relative_path = os.path.relpath(
       path='.', start=os.path.dirname(documentation_path(full_name)) or '.')
+  # Convert from OS-specific path to URL/POSIX path.
+  relative_path = posixpath.join(*relative_path.split(os.path.sep))
 
   with parser_config.reference_resolver.temp_prefix(relative_path):
     page_info.set_doc(
@@ -1497,6 +1499,9 @@ def _get_defined_in(
       continue
     else:
       code_url_prefix = temp_prefix
+      # rel_path is currently a platform-specific path, so we need to convert
+      # it to a posix path (for lack of a URL path).
+      rel_path = posixpath.join(*rel_path.split(os.path.sep))
       break
 
   # No link if the file was not found in a `base_dir`, or the prefix is None.
@@ -1534,10 +1539,10 @@ def _get_defined_in(
   elif re.match(r'.*_pb2\.py$', rel_path):
     # The _pb2.py files all appear right next to their defining .proto file.
     rel_path = rel_path[:-7] + '.proto'
-    return _FileLocation(base_url=os.path.join(code_url_prefix, rel_path))
+    return _FileLocation(base_url=posixpath.join(code_url_prefix, rel_path))
   else:
     return _FileLocation(
-        base_url=os.path.join(code_url_prefix, rel_path),
+        base_url=posixpath.join(code_url_prefix, rel_path),
         start_line=start_line,
         end_line=end_line)
 

tools/tensorflow_docs/api_generator/reference_resolver.py

@@ -20,6 +20,7 @@
 import html
 import json
 import os
+import posixpath
 import re
 
 from typing import Dict, List, Optional
@@ -350,7 +351,7 @@ def reference_to_url(self, ref_full_name):
 
     if self._link_prefix is None:
       raise ValueError('you must set the `link_prefix`')
-    url = os.path.join(self._link_prefix, rel_path)
+    url = posixpath.join(self._link_prefix, rel_path)
     return url
 
   def _one_ref(self, match, full_name=None):
@@ -411,6 +412,6 @@ def _cc_link(self, string, link_text):
     # relative_path_to_root gets you to api_docs/python, we go from there
     # to api_docs/cc, and then add ret.
     cc_relative_path = os.path.normpath(
-        os.path.join(self._link_prefix, '../cc', ret))
+        posixpath.join(self._link_prefix, '../cc', ret))
 
     return f'<a href="{cc_relative_path}"><code>{link_text}</code></a>'