Thrift: docstring revamp step 2.

Summary:
It was a bad idea to let doxygen comments become a part of the parse tree.
We now get them a totally different way.  The lexer stashes the docsting
contents in a global, and the parser actions (not the rules) pull it out.
This should prevent doxygen comments from ever causing parse errors.

Blame Rev: 52678, 52732

Reviewed By: mcslee

Test Plan:
Recompiled thrift.
Thrifted a bunch of files and saw no parse errors (or C++ compile errors).
Thrifted DocTest.thrift with dump_docs on.

Revert Plan: ok


git-svn-id: https://svn.apache.org/repos/asf/incubator/thrift/trunk@665201 13f79535-47bb-0310-9956-ffa450edef68
diff --git a/compiler/cpp/src/main.cc b/compiler/cpp/src/main.cc
index 76676f3..ba88ae3 100644
--- a/compiler/cpp/src/main.cc
+++ b/compiler/cpp/src/main.cc
@@ -117,6 +117,16 @@
 char* g_time_str;
 
 /**
+ * The last parsed doctext comment.
+ */
+char* g_doctext;
+
+/**
+ * The location of the last parsed doctext comment.
+ */
+int g_doctext_lineno;
+
+/**
  * Flags to control code generation
  */
 bool gen_cpp = false;
@@ -295,6 +305,18 @@
 }
 
 /**
+ * Clears any previously stored doctext string.
+ * Also prints a warning if we are discarding information.
+ */
+void clear_doctext() {
+  if (g_doctext != NULL) {
+    pwarning(2, "Uncaptured doctext at on line %d.", g_doctext_lineno);
+  }
+  free(g_doctext);
+  g_doctext = NULL;
+}
+
+/**
  * Cleans up text commonly found in doxygen-like comments
  *
  * Warning: if you mix tabs and spaces in a non-uniform way,