[PATCH 42/42] docs/qapidoc: add intermediate output debugger

[John Snow <jsnow@redhat.com>]

Add debugging output for the qapidoc transmogrifier - setting DEBUG=1
will produce .ir files (one for each qapidoc directive) that write the
generated rst file to disk to allow for easy debugging and verification
of the generated document.

Signed-off-by: John Snow <jsnow@redhat.com>
---
 docs/sphinx/qapidoc.py | 41 +++++++++++++++++++++++++++++++++++++----
 1 file changed, 37 insertions(+), 4 deletions(-)

diff --git a/docs/sphinx/qapidoc.py b/docs/sphinx/qapidoc.py
index e7da5b2225f..7b895c3668e 100644
--- a/docs/sphinx/qapidoc.py
+++ b/docs/sphinx/qapidoc.py
@@ -36,7 +36,7 @@
 from typing import Dict, List, Optional
 
 from docutils import nodes
-from docutils.parsers.rst import Directive, directives
+from docutils.parsers.rst import directives
 from docutils.statemachine import StringList, ViewList
 from qapi.error import QAPIError, QAPISemError
 from qapi.gen import QAPISchemaVisitor
@@ -60,7 +60,7 @@
 from sphinx.directives.code import CodeBlock
 from sphinx.errors import ExtensionError
 from sphinx.util import logging
-from sphinx.util.docutils import switch_source_input
+from sphinx.util.docutils import SphinxDirective, switch_source_input
 from sphinx.util.nodes import nested_parse_with_titles
 
 
@@ -1053,7 +1053,7 @@ def visit_module(self, name):
         super().visit_module(name)
 
 
-class NestedDirective(Directive):
+class NestedDirective(SphinxDirective):
     def run(self):
         raise NotImplementedError
 
@@ -1122,10 +1122,43 @@ def transmogrify(self, schema) -> nodes.Element:
                 node.document = self.state.document
                 self.state.nested_parse(content, 0, contentnode)
         logger.info("Transmogrifier's nested parse completed.")
+
+        if self.env.app.verbosity >= 2 or os.environ.get("DEBUG"):
+            argname = "_".join(Path(self.arguments[0]).parts)
+            name = Path(argname).stem + ".ir"
+            self.write_intermediate(content, name)
+
         sys.stdout.flush()
-
         return contentnode
 
+    def write_intermediate(self, content, filename):
+        logger.info(
+            "writing intermediate rST for '%s' to '%s'",
+            self.arguments[0],
+            filename,
+        )
+
+        srctree = Path(self.env.app.config.qapidoc_srctree).resolve()
+        outlines = []
+        lcol_width = 0
+
+        for i, line in enumerate(content):
+            src, lineno = content.info(i)
+            src = Path(src).resolve()
+            src = src.relative_to(srctree)
+
+            lcol = f"{src}:{lineno:04d}"
+            lcol_width = max(lcol_width, len(lcol))
+            outlines.append((lcol, line))
+
+        with open(filename, "w", encoding="UTF-8") as outfile:
+            for lcol, rcol in outlines:
+                outfile.write(lcol.rjust(lcol_width))
+                outfile.write(" |")
+                if rcol:
+                    outfile.write(f" {rcol}")
+                outfile.write("\n")
+
     def legacy(self, schema) -> nodes.Element:
         vis = QAPISchemaGenRSTVisitor(self)
         vis.visit_begin(schema)
-- 
2.48.1