[PATCH v4 14/14] docs: conf.py: properly handle include and exclude patterns

When one does:
	make SPHINXDIRS="netlink/specs" htmldocs

the build would break because a statically-defined pattern
like:

	include_patterns = [
		...
		'netlink/specs/*.yaml',
	]

would be pointing to Documentation/netlink/specs/netlink/specs,
as the path there is relative. Also, when SPHINXDIRS is used,
the exclude_pattern = [ "output" ] is also wrong.

Fix conf.py to generate relative include/exclude patterns,
relative to the SOURCEDIR sphinx-dir parameter.

Signed-off-by: Mauro Carvalho Chehab <[email protected]>
---
 Documentation/conf.py | 58 ++++++++++++++++++++++++++++++++++---------
 1 file changed, 46 insertions(+), 12 deletions(-)

diff --git a/Documentation/conf.py b/Documentation/conf.py
index 62a51ac64b95..be678bdf95d4 100644
--- a/Documentation/conf.py
+++ b/Documentation/conf.py
@@ -17,6 +17,52 @@ import os
 import sphinx
 import shutil
 
+# Location of Documentation/ directory
+doctree = os.path.abspath('.')
+
+# List of patterns that don't contain directory names, in glob format.
+include_patterns = ['**.rst']
+exclude_patterns = []
+
+# List of patterns that contain directory names in glob format.
+dyn_include_patterns = ['netlink/specs/**.yaml']
+dyn_exclude_patterns = ['output']
+
+def setup(app):
+    """
+    On Sphinx, all directories are relative to what it is passed as
+    SOURCEDIR parameter for sphinx-build. Due to that, all patterns
+    that have directory names on it need to be dynamically set, after
+    converting them to a relative patch.
+
+    As Sphinx doesn't include any patterns outside SOURCEDIR, we should
+    exclude relative patterns that start with "../".
+    """
+
+    sourcedir = app.srcdir  # full path to the source directory
+    builddir = os.environ.get("BUILDDIR")
+
+    # setup include_patterns dynamically
+    for p in dyn_include_patterns:
+        full = os.path.join(doctree, p)
+
+        rel_path = os.path.relpath(full, start = app.srcdir)
+        if rel_path.startswith("../"):
+            continue
+
+        app.config.include_patterns.append(rel_path)
+
+    # setup exclude_patterns dynamically
+    for p in dyn_exclude_patterns:
+        full = os.path.join(doctree, p)
+
+        rel_path = os.path.relpath(full, start = app.srcdir)
+        if rel_path.startswith("../"):
+            continue
+
+        app.config.exclude_patterns.append(rel_path)
+
+
 # helper
 # ------
 
@@ -220,18 +266,6 @@ language = 'en'
 # Else, today_fmt is used as the format for a strftime call.
 #today_fmt = '%B %d, %Y'
 
-# List of patterns, relative to source directory, that match files and
-# directories.
-include_patterns = [
-	'**.rst',
-	'netlink/specs/*.yaml',
-]
-
-# patterns to ignore when looking for source files.
-exclude_patterns = [
-	'output',
-]
-
 # The reST default role (used for this markup: `text`) to use for all
 # documents.
 #default_role = None
-- 
2.49.0