Issue #1234, #2058 - Rewrite log facility, improving thread implementation

src/plugin/PluginDebug.h

 /*
  * This file is part of Adblock Plus <https://adblockplus.org/>,
- * Copyright (C) 2006-2015 Eyeo GmbH
+ * Copyright (C) 2006-2016 Eyeo GmbH
  *
  * Adblock Plus is free software: you can redistribute it and/or modify
  * it under the terms of the GNU General Public License version 3 as
  * published by the Free Software Foundation.
  *
  * Adblock Plus is distributed in the hope that it will be useful,
  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  * GNU General Public License for more details.
  *
  * You should have received a copy of the GNU General Public License
  * along with Adblock Plus.  If not, see <http://www.gnu.org/licenses/>.
  */
 
 #ifndef _PLUGIN_DEBUG_H_
 #define _PLUGIN_DEBUG_H_
 
 #include <memory>
 #include <mutex>
+#include <string>
 
 namespace Trace
 {
   /**
    */
   struct Location
   {
     std::string prefixText;
     std::string postfixText;
 
@@ skipping 51 matching lines @@
   static void DebugResultDomain(const std::wstring& domain);
   static void DebugResultBlocking(const std::wstring& type, const std::wstring& src, const std::wstring& domain);
   static void DebugResultHiding(const std::wstring& tag, const std::wstring& id, const std::wstring& filter);
 #endif
 
 #if (defined ENABLE_DEBUG_RESULT_IGNORED)
   static void DebugResultIgnoring(const std::wstring& type, const std::wstring& src, const std::wstring& domain);
 #endif
 };
 
+/**
+* Convert a pointer to a hexadecimal literal (0x...)
+*
+* The length of the literal varies with pointer size:
+*   10 characters for WIN32, and 18 for WIN64.
+*/
+std::wstring ToHexLiteral(const void*);
+
 /*
  * Forward declaration.
  */
 class LogQueue;
 
 /**
  * This class maintains a singleton LogQueue in existence.
  *
  * This class exists because it's not possible to use a static declaration for
  *  'std::thread' or any class that contains one, such as 'ActiveQueue'.
@@ skipping 18 matching lines @@
  */
 class LogQueueReference
 {
   friend LogQueue;
 
   typedef std::shared_ptr<LogQueue> pointer;
 
   /**
    * The class-wide reference to the debug queue.
    */
   static pointer queueMasterReference;

[sergei, 2015/10/01 15:50:07]

Why do we need more static stuff? We have already singletons for example
CAdblockPlusClient and CPluginSettings, why not to combine them all in one
singleton?

[Eric, 2015/10/08 21:05:41]

In the present case, we want a single log facility for the whole DLL. Read the
comment above on why this isn't a simple static declaration, which would indeed
be simpler.
How would moving things out of their own scopes and creating a new _de facto_
global scope provide any benefit whatsoever? There's a reason for the consensus
that global variables are bad. When you've got separable responsibilities, you
put them in separate objects.

In fact, the lifetimes of these other objects do _not_ coincide with that of the
log queue. The reason is in the comment above, because you can't statically
initialize a thread in a DLL. Even if combining everything were a good idea
(which it's not), you'd need to seriously rework the initialization of these
other classes.

 
   /**
    * The instance reference to the debug queue.
    */
   pointer queueReference;
 
   /**
    * Mutex to allow joint serialization of constructor/destructor calls.
    */
   static std::mutex mutex;
 
 public:
   LogQueueReference();
   ~LogQueueReference();
 };
 
 #endif // _PLUGIN_DEBUG_H_