Subzero: Doxygenify TODO comments.

Doxyfile

Index: Doxyfile
diff --git a/Doxyfile b/Doxyfile
index c6f726e5dc2b9c1028b362079b19eb622cd7cf16..8e88ed11125a827b40f5d62cbad5b14a8f6a2b5f 100644
--- a/Doxyfile
+++ b/Doxyfile
@@ -848,7 +848,16 @@ IMAGE_PATH             =
 # code is scanned, but not when the output code is generated. If lines are added
 # or removed, the anchors will not be placed correctly.
 
-INPUT_FILTER           =
+# This script transforms TODO strings into a @todo form.  It also transforms
+# "//" into "///" (but only when there are exactly 2 '/' characters in a row).
+# The first pattern matches "//" at the beginning of the line, and the second
+# pattern matches a mid-line "//".  The third pattern matches "TODO " or
+# "TODO(owner)" or "TODO:".  This should cover the usual TODO patterns, while
+# not falsely matching e.g. a call to a function whose name ends in "TODO".
+
+INPUT_FILTER           = "sed -e 's?^//\([^/]\)?///\1?' \
+                              -e 's?\([^/]\)//\([^/]\)?\1///\2?' \
+                              -e 's/ \(TODO[ (:]\)/ @todo \1/g'"
 
 # The FILTER_PATTERNS tag can be used to specify filters on a per file pattern
 # basis. Doxygen will compare the file name with each pattern and apply the