Allow Javadoc-style comment blocks with a Doxyfile variable

Javadoc allows comments like this (which I refer to as "banner" comments)

/*****************
 *
 *****************/

but doxygen does not recognize them.

Instead, the doxygen manual says to do this

/*************//**
 *
 ****************/

which some users aren't even aware is required. It also behaves poorly with clang-format.

I'm proposing to add a Doxyfile boolean option JAVADOC_BANNER which will default to NO. When set to YES, it will consider the first and second comments above to be equivalent.

However, I don't believe that the JAVADOC_BANNER option should default to YES, as there are likely a number of projects who have used the former syntax with full expectation that it would *not* appear in their documentation.

At least having the JAVADOC_BANNER default to NO allows users to opt-in voluntarily by adding JAVADOC_BANNER = YES to their Doxyfile. If the consensus is to make it a default at a later time, first a warning can be added during build that should trigger users to modify their comment style, and then eventually the default could be set to JAVADOC_BANNER = YES, or the config option could be removed entirely and it would just always be enabled.

5 files changed, 116 insertions, 0 deletions

diff --git a/examples/CMakeLists.txt b/examples/CMakeLists.txt
index 0f34c6d..967f3d4 100644
--- a/examples/CMakeLists.txt
+++ b/examples/CMakeLists.txt
@@ -23,6 +23,7 @@ add_custom_target(examples
                 ${PROJECT_BINARY_DIR}/html/examples/enum/html/index.html
                 ${PROJECT_BINARY_DIR}/html/examples/file/html/index.html
                 ${PROJECT_BINARY_DIR}/html/examples/func/html/index.html
+                ${PROJECT_BINARY_DIR}/html/examples/javadoc-banner/html/index.html
                 ${PROJECT_BINARY_DIR}/html/examples/page/html/index.html
                 ${PROJECT_BINARY_DIR}/html/examples/relates/html/index.html
                 ${PROJECT_BINARY_DIR}/html/examples/author/html/index.html
@@ -85,6 +86,13 @@ add_custom_command(
 )
 
 add_custom_command(
+	COMMAND ${EXECUTABLE_OUTPUT_PATH}/doxygen javadoc-banner.cfg
+        COMMAND ${PYTHON_EXECUTABLE}  ${TOP}/examples/strip_example.py  < ${PROJECT_BINARY_DIR}/html/examples/javadoc-banner/latex/refman.tex > ${PROJECT_BINARY_DIR}/html/examples/javadoc-banner/latex/refman_doc.tex
+	DEPENDS doxygen javadoc-banner.h javadoc-banner.cfg ${TOP}/examples/strip_example.py
+	OUTPUT ${PROJECT_BINARY_DIR}/html/examples/javadoc-banner/html/index.html ${PROJECT_BINARY_DIR}/html/examples/javadoc-banner/latex/refman_doc.tex
+)
+
+add_custom_command(
 	COMMAND ${EXECUTABLE_OUTPUT_PATH}/doxygen page.cfg
         COMMAND ${PYTHON_EXECUTABLE}  ${TOP}/examples/strip_example.py  < ${PROJECT_BINARY_DIR}/html/examples/page/latex/refman.tex > ${PROJECT_BINARY_DIR}/html/examples/page/latex/refman_doc.tex
 	DEPENDS doxygen page.doc page.cfg ${TOP}/examples/strip_example.py
diff --git a/examples/javadoc-banner.cfg b/examples/javadoc-banner.cfg
new file mode 100644
index 0000000..d650dbc
--- /dev/null
+++ b/examples/javadoc-banner.cfg
@@ -0,0 +1,15 @@
+PROJECT_NAME     = "Javadoc Banner"
+OUTPUT_DIRECTORY = ../html/examples/javadoc-banner
+GENERATE_LATEX   = YES
+GENERATE_MAN     = NO
+GENERATE_RTF     = NO
+CASE_SENSE_NAMES = NO
+INPUT            = javadoc-banner.h
+STRIP_CODE_COMMENTS = NO
+QUIET            = YES
+JAVADOC_AUTOBRIEF = YES
+JAVADOC_BANNER = YES
+SEARCHENGINE     = NO
+COMPACT_LATEX = YES
+LATEX_HIDE_INDICES     = YES
+EXTRACT_ALL = YES
diff --git a/examples/javadoc-banner.h b/examples/javadoc-banner.h
new file mode 100644
index 0000000..bc413bb
--- /dev/null
+++ b/examples/javadoc-banner.h
@@ -0,0 +1,45 @@
+/**
+ * A brief history of JavaDoc-style (C-style) comments.
+ *
+ * This is the typical JavaDoc-style C-style comment. It starts with two
+ * asterisks.
+ *
+ * @param theory Even if there is only one possible unified theory. it is just a
+ *               set of rules and equations.
+ */
+void cstyle( int theory );
+
+/*******************************************************************************
+ * A brief history of JavaDoc-style (C-style) banner comments.
+ *
+ * This is the typical JavaDoc-style C-style "banner" comment. It starts with
+ * a forward slash followed by some number, n, of asterisks, where n > 2. It's
+ * written this way to be more "visible" to developers who are reading the
+ * source code.
+ *
+ * Often, developers are unaware that this is not (by default) a valid Doxygen
+ * comment block!
+ *
+ * However, as long as JAVADOC_BLOCK = YES is added to the Doxyfile, it will
+ * work as expected.
+ *
+ * This style of commenting behaves well with clang-format.
+ *
+ * @param theory Even if there is only one possible unified theory. it is just a
+ *               set of rules and equations.
+ ******************************************************************************/
+void javadocBanner( int theory );
+
+/***************************************************************************//**
+ * A brief history of Doxygen-style banner comments.
+ *
+ * This is a Doxygen-style C-style "banner" comment. It starts with a "normal"
+ * comment and is then converted to a "special" comment block near the end of
+ * the first line. It is written this way to be more "visible" to developers
+ * who are reading the source code.
+ * This style of commenting behaves poorly with clang-format.
+ *
+ * @param theory Even if there is only one possible unified theory. it is just a
+ *               set of rules and equations.
+ ******************************************************************************/
+void doxygenBanner( int theory );
diff --git a/src/config.xml b/src/config.xml
index 8820fe7..1a3b256 100644
--- a/src/config.xml
+++ b/src/config.xml
@@ -480,6 +480,17 @@ Go to the <a href="commands.html">next</a> section or return to the
 ]]>
       </docs>
     </option>
+    <option type='bool' id='JAVADOC_BANNER' defval='0'>
+      <docs>
+<![CDATA[
+  If the \c JAVADOC_BANNER tag is set to \c YES then doxygen
+  will interpret a line such as "/***************" as being the
+  beginning of a Javadoc-style comment "banner". If set to \c NO, the
+  Javadoc-style will behave just like regular comments and it will
+  not be interpreted by doxygen.
+]]>
+      </docs>
+    </option>
     <option type='bool' id='QT_AUTOBRIEF' defval='0'>
       <docs>
 <![CDATA[
diff --git a/src/scanner.l b/src/scanner.l
index d3902b3..4b1172f 100644
--- a/src/scanner.l
+++ b/src/scanner.l
@@ -6252,6 +6252,43 @@ OPERATOR  "operator"{B}*({ARITHOP}|{ASSIGNOP}|{LOGICOP}|{BITOP})
 					  startCommentBlock(FALSE);
 					  BEGIN( DocBlock );
 					}
+<FindMembers,FindFields,MemberSpec,FuncQual,SkipCurly,Operator,ClassVar,SkipInits,Bases,OldStyleArgs>"/**"[*]+{BL} {
+
+					  static bool javadocBanner = Config_getBool(JAVADOC_BANNER);
+
+					  if( javadocBanner ) {
+						  lastDocContext = YY_START;
+
+						  //printf("Found comment banner at %s:%d\n",yyFileName,yyLineNr);
+						  if (current_root->section & Entry::SCOPE_MASK)
+	                                          {
+						    current->inside = current_root->name+"::";
+	                                          }
+						  current->docLine = yyLineNr;
+						  current->docFile = yyFileName;
+						  docBlockContext = YY_START;
+						  docBlockInBody  = YY_START==SkipCurly;
+	                                          static bool javadocAutoBrief = Config_getBool(JAVADOC_AUTOBRIEF);
+						  docBlockAutoBrief = javadocAutoBrief;
+
+	                                          QCString indent;
+	                                          indent.fill(' ',computeIndent(yytext,g_column));
+	                                          docBlock=indent;
+
+						  if (docBlockAutoBrief)
+						  {
+						    current->briefLine = yyLineNr;
+						    current->briefFile = yyFileName;
+						  }
+						  startCommentBlock(FALSE);
+						  BEGIN( DocBlock );
+					  } else {
+						  current->program += yytext ;
+						  lastContext = YY_START ;
+						  BEGIN( Comment ) ;
+					  }
+
+					}
 <FindMembers,FindFields,MemberSpec,FuncQual,SkipCurly,Operator,ClassVar,SkipInits,Bases,OldStyleArgs>("//"{B}*)?"/**"/[^/*] {
   					  removeSlashes=(yytext[1]=='/');
 					  lastDocContext = YY_START;