doc: Add build env variable to know if doxygen has run

Some extensions may be able to run faster if they can check if Doxygen
contents has changed from one build to the other

Signed-off-by: Benjamin Cabé <[email protected]>

Author: kartben

doc/_extensions/zephyr/api_overview.py

@@ -141,6 +141,9 @@ def sync_contents(app: Sphinx) -> None:
     else:
         doxygen_out_dir = Path(app.outdir) / "_doxygen"
 
+    if not app.env.doxygen_input_changed:
+        return
+
     doxygen_xml_dir = doxygen_out_dir / "xml"
     groups = parse_xml_dir(doxygen_xml_dir)
 

doc/_extensions/zephyr/doxyrunner.py

@@ -362,8 +362,8 @@ def doxygen_build(app: Sphinx) -> None:
     )
 
     logger.info("Checking if Doxygen needs to be run...")
-    changed = doxygen_input_has_changed(app.env, doxyfile)
-    if not changed:
+    app.env.doxygen_input_changed = doxygen_input_has_changed(app.env, doxyfile)
+    if not app.env.doxygen_input_changed:
         logger.info("Doxygen build will be skipped (no changes)!")
         return