Use Dbg() for debug output in both core and plugins.

example/plugins/c-api/cache_scan/cache_scan.cc

@@ -36,7 +36,7 @@
 
 #define PLUGIN_NAME "cache_scan"
 
-static const TSDbgCtl *const dbg_ctl = TSDbgCtlCreate(PLUGIN_NAME);
+static DbgCtl dbg_ctl{PLUGIN_NAME};
 
 static TSCont global_contp;
 
@@ -285,14 +285,14 @@ handle_io(TSCont contp, TSEvent event, void * /* edata ATS_UNUSED */)
     return 0;
   } break;
   case TS_EVENT_VCONN_WRITE_READY: {
-    TSDbg(dbg_ctl, "ndone: %" PRId64 " total_bytes: % " PRId64, TSVIONDoneGet(cstate->write_vio), cstate->total_bytes);
+    Dbg(dbg_ctl, "ndone: %" PRId64 " total_bytes: % " PRId64, TSVIONDoneGet(cstate->write_vio), cstate->total_bytes);
     cstate->write_pending = false;
     // the cache scan handler should call vio reenable when there is
     // available data
     return 0;
   } break;
   case TS_EVENT_VCONN_WRITE_COMPLETE: {
-    TSDbg(dbg_ctl, "write complete");
+    Dbg(dbg_ctl, "write complete");
     cstate->done = 1;
     cleanup(contp);
   } break;
@@ -311,7 +311,7 @@ handle_io(TSCont contp, TSEvent event, void * /* edata ATS_UNUSED */)
 static int
 cache_intercept(TSCont contp, TSEvent event, void *edata)
 {
-  TSDbg(dbg_ctl, "cache_intercept event: %d", event);
+  Dbg(dbg_ctl, "cache_intercept event: %d", event);
 
   switch (event) {
   case TS_EVENT_NET_ACCEPT:
@@ -439,7 +439,7 @@ setup_request(TSCont contp, TSHttpTxn txnp)
         end         = start + del_url_len;
 
         cstate->key_to_delete = TSCacheKeyCreate();
-        TSDbg(dbg_ctl, "deleting url: %s", start);
+        Dbg(dbg_ctl, "deleting url: %s", start);
 
         TSMBuffer urlBuf = TSMBufferCreate();
         TSMLoc urlLoc;
@@ -463,9 +463,9 @@ setup_request(TSCont contp, TSHttpTxn txnp)
     }
 
     TSContDataSet(scan_contp, cstate);
-    TSDbg(dbg_ctl, "setup cache intercept");
+    Dbg(dbg_ctl, "setup cache intercept");
   } else {
-    TSDbg(dbg_ctl, "not a cache iter request");
+    Dbg(dbg_ctl, "not a cache iter request");
   }
 
 Ldone:

include/ts/DbgCtl.h

@@ -0,0 +1,120 @@
+/** @file
+
+  DbgCtl class header file.
+
+  @section license License
+
+  Licensed to the Apache Software Foundation (ASF) under one
+  or more contributor license agreements.  See the NOTICE file
+  distributed with this work for additional information
+  regarding copyright ownership.  The ASF licenses this file
+  to you under the Apache License, Version 2.0 (the
+  "License"); you may not use this file except in compliance
+  with the License.  You may obtain a copy of the License at
+
+      http://www.apache.org/licenses/LICENSE-2.0
+
+  Unless required by applicable law or agreed to in writing, software
+  distributed under the License is distributed on an "AS IS" BASIS,
+  WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+  See the License for the specific language governing permissions and
+  limitations under the License.
+ */
+
+#pragma once
+
+#include <atomic>
+#include <utility>
+
+#include <ts/apidefs.h> // For TS_PRINTFLIKE
+
+class DiagsConfigState;
+
+class DbgCtl
+{
+public:
+  // Tag is a debug tag.  Debug output associated with this control will be output when debug output
+  // is enabled globally, and the tag matches the configured debug tag regular expression.
+  //
+  DbgCtl(char const *tag) : _ptr{_new_reference(tag)} {}
+
+  ~DbgCtl() { _rm_reference(); }
+
+  bool
+  tag_on() const
+  {
+    return _ptr->second;
+  }
+
+  char const *
+  tag() const
+  {
+    return _ptr->first;
+  }
+
+  bool
+  on() const
+  {
+    auto m{_config_mode.load(std::memory_order_relaxed)};
+    if (!m) {
+      return false;
+    }
+    if (!_ptr->second) {
+      return false;
+    }
+    if (m & 1) {
+      return true;
+    }
+    return (2 == m) && (_override_global_on());
+  }
+
+  static bool
+  global_on()
+  {
+    auto m{_config_mode.load(std::memory_order_relaxed)};
+    if (!m) {
+      return false;
+    }
+    if (m & 1) {
+      return true;
+    }
+    return (2 == m) && (_override_global_on());
+  }
+
+  // Call this when the compiled regex to enable tags may have changed.
+  //
+  static void update();
+
+  // For use in DbgPrint() only.
+  //
+  static void print(char const *tag, char const *file, char const *function, int line, char const *fmt_str, ...)
+    TS_PRINTFLIKE(5, 6);
+
+private:
+  using _TagData = std::pair<char const *const, bool>;
+
+  _TagData const *const _ptr;
+
+  static const _TagData *_new_reference(char const *tag);
+
+  static void _rm_reference();
+
+  class _RegistryAccessor;
+
+  static std::atomic<int> _config_mode;
+
+  static bool _override_global_on();
+
+  friend class DiagsConfigState;
+};
+
+// Always generates output when called.
+//
+#define DbgPrint(CTL, ...) (DbgCtl::print((CTL).tag(), __FILE__, __FUNCTION__, __LINE__, __VA_ARGS__))
+
+#define Dbg(CTL, ...)               \
+  do {                              \
+    if ((CTL).on()) {               \
+      DbgPrint((CTL), __VA_ARGS__); \
+    }                               \
+  } while (false)

include/ts/Makefile.am

@@ -20,6 +20,7 @@ library_includedir=$(includedir)/ts
 
 library_include_HEADERS = \
 	apidefs.h \
+	DbgCtl.h \
 	ts.h \
 	remap.h \
 	experimental.h \

include/ts/apidefs.h.in

@@ -1114,11 +1114,6 @@ char const TS_VERSION_STRING[] = "@TS_VERSION_STRING@";
     TSIOBufferWaterMark buffer_water_mark;
   };
 
-  struct TSDbgCtl {
-    char volatile on; // Flag
-    char const *tag;
-  };
-
   /* --------------------------------------------------------------------------
      URL schemes */
   extern const char *TS_URL_SCHEME_FILE;

include/ts/ts.h

@@ -33,6 +33,7 @@
 
 #include <ts/apidefs.h>
 #include <ts/parentselectdefs.h>
+#include <ts/DbgCtl.h>
 
 class DiagsConfigState;
 
@@ -2206,54 +2207,6 @@ namespace c
   if (diags_on_for_plugins) \
   TSDebug
 
-  class TSDbgCtlDetail
-  {
-    friend bool TSIsDbgCtlSet(TSDbgCtl const *ctlp);
-
-    static bool debug_on;
-
-    friend class ::DiagsConfigState;
-  };
-
-  inline bool
-  TSIsDbgCtlSet(TSDbgCtl const *ctlp)
-  {
-    return (TSDbgCtlDetail::debug_on && ctlp->on);
-  }
-
-/**
-    Output a debug line if the debug output control is turned on.
-
-    @param ctlp pointer to TSDbgCtl, returned by TSDbgCtlCreate().
-    @param ...  Format string and (optional) arguments.
- */
-#define TSDbg(ctlp, ...)              \
-  do {                                \
-    if (TSIsDbgCtlSet(ctlp)) {        \
-      _TSDbg(ctlp->tag, __VA_ARGS__); \
-    }                                 \
-  } while (0)
-
-  /**
-      Return a pointer for use with TSDbg().  For good performance,
-      this should be called in TSPluginInit() or TSRemapInit(), or in
-      static initialization in C++ (with the result stored in a
-      static pointer).
-
-      @param tag Debug tag for the control.
-   */
-  TSDbgCtl const *TSDbgCtlCreate(char const *tag);
-
-  /**
-      Destroy (dereference) a debug control object previously created
-      with TSDbgCtlCreate().
-
-      @param dbg_ctl pointer to debug control object.
-   */
-  void TSDbgCtlDestroy(TSDbgCtl const *dbg_ctl);
-
-  void _TSDbg(const char *tag, const char *format_str, ...) TS_PRINTFLIKE(2, 3); /* Not for direct use. */
-
   /* --------------------------------------------------------------------------
      logging api */