added wxLogChain and wxLogPassThrough classes

git-svn-id: https://svn.wxwidgets.org/svn/wx/wxWidgets/trunk@10961 c3d73ce0-8a6f-49c7-b76d-6d57e0e08775

include/wx/log.h

@@ -238,7 +238,7 @@ public:
     // redirect log output to a FILE
     wxLogStderr(FILE *fp = (FILE *) NULL);
 
-private:
+protected:
     // implement sink function
     virtual void DoLogString(const wxChar *szString, time_t t);
 
@@ -246,6 +246,7 @@ private:
 };
 
 #if wxUSE_STD_IOSTREAM
+
 // log everything to an "ostream", cerr by default
 class WXDLLEXPORT wxLogStream : public wxLog
 {
@@ -260,7 +261,8 @@ protected:
     // using ptr here to avoid including <iostream.h> from this file
     wxSTD ostream *m_ostr;
 };
-#endif
+
+#endif // wxUSE_STD_IOSTREAM
 
 // the following log targets are only compiled in if the we're compiling the
 // GUI part (andnot just the base one) of the library, they're implemented in
@@ -286,6 +288,89 @@ private:
 
 #endif // wxUSE_TEXTCTRL
 
+// ----------------------------------------------------------------------------
+// /dev/null log target: suppress logging until this object goes out of scope
+// ----------------------------------------------------------------------------
+
+// example of usage:
+/*
+    void Foo()
+    {
+        wxFile file;
+
+        // wxFile.Open() normally complains if file can't be opened, we don't
+        // want it
+        wxLogNull logNo;
+
+        if ( !file.Open("bar") )
+            ... process error ourselves ...
+
+        // ~wxLogNull called, old log sink restored
+    }
+ */
+class WXDLLEXPORT wxLogNull
+{
+public:
+    wxLogNull() { m_flagOld = wxLog::EnableLogging(FALSE); }
+    ~wxLogNull() { (void)wxLog::EnableLogging(m_flagOld);   }
+
+private:
+    bool m_flagOld; // the previous value of the wxLog::ms_doLog
+};
+
+// ----------------------------------------------------------------------------
+// chaining log target: installs itself as a log target and passes all
+// messages to the real log target given to it in the ctor but also forwards
+// them to the previously active one
+//
+// note that you don't have to call SetActiveTarget() with this class, it
+// does it itself in its ctor
+// ----------------------------------------------------------------------------
+
+class WXDLLEXPORT wxLogChain : public wxLog
+{
+public:
+    wxLogChain(wxLog *logger);
+    virtual ~wxLogChain() { delete m_logOld; }
+
+    // change the new log target
+    void SetLog(wxLog *logger);
+
+    // this can be used to temporarily disable (and then reenable) passing
+    // messages to the old logger (by default we do pass them)
+    void PassMessages(bool bDoPass) { m_bPassMessages = bDoPass; }
+
+    // are we passing the messages to the previous log target?
+    bool IsPassingMessages() const { return m_bPassMessages; }
+
+    // return the previous log target (may be NULL)
+    wxLog *GetOldLog() const { return m_logOld; }
+
+    // override base class version to flush the old logger as well
+    virtual void Flush();
+
+protected:
+    // pass the chain to the old logger if needed
+    virtual void DoLog(wxLogLevel level, const wxChar *szString, time_t t);
+
+private:
+    // the current log target
+    wxLog *m_logNew;
+
+    // the previous log target
+    wxLog *m_logOld;
+
+    // do we pass the messages to the old logger?
+    bool m_bPassMessages;
+};
+
+// a chain log target which uses itself as the new logger
+class WXDLLEXPORT wxLogPassThrough : public wxLogChain
+{
+public:
+    wxLogPassThrough() : wxLogChain(this) { }
+};
+
 // ----------------------------------------------------------------------------
 // GUI log target, the default one for wxWindows programs
 // ----------------------------------------------------------------------------
@@ -325,13 +410,14 @@ protected:
 
 #if wxUSE_LOGWINDOW
 
-class WXDLLEXPORT wxLogWindow : public wxLog
+class WXDLLEXPORT wxLogWindow : public wxLogPassThrough
 {
 public:
     wxLogWindow(wxFrame *pParent,         // the parent frame (can be NULL)
-            const wxChar *szTitle,      // the title of the frame
-            bool bShow = TRUE,        // show window immediately?
-            bool bPassToOld = TRUE);  // pass log messages to the old target?
+                const wxChar *szTitle,    // the title of the frame
+                bool bShow = TRUE,        // show window immediately?
+                bool bPassToOld = TRUE);  // pass messages to the old target?
+
     ~wxLogWindow();
 
     // window operations
@@ -340,21 +426,6 @@ public:
         // retrieve the pointer to the frame
     wxFrame *GetFrame() const;
 
-    // accessors
-        // the previous log target (may be NULL)
-    wxLog *GetOldLog() const { return m_pOldLog; }
-        // are we passing the messages to the previous log target?
-    bool IsPassingMessages() const { return m_bPassMessages; }
-
-    // we can pass the messages to the previous log target (we're in this mode by
-    // default: we collect all messages in the window, but also let the default
-    // processing take place)
-    void PassMessages(bool bDoPass) { m_bPassMessages = bDoPass; }
-
-    // base class virtuals
-        // we don't need it ourselves, but we pass it to the previous logger
-    virtual void Flush();
-
     // overridables
         // called immediately after the log frame creation allowing for
         // any extra initializations
@@ -373,8 +444,6 @@ protected:
     virtual void DoLogString(const wxChar *szString, time_t t);
 
 private:
-    bool        m_bPassMessages;  // pass messages to m_pOldLog?
-    wxLog      *m_pOldLog;        // previous log target
     wxLogFrame *m_pLogFrame;      // the log frame
 };
 
@@ -382,33 +451,6 @@ private:
 
 #endif // wxUSE_GUI
 
-// ----------------------------------------------------------------------------
-// /dev/null log target: suppress logging until this object goes out of scope
-// ----------------------------------------------------------------------------
-
-// example of usage:
-/*
-   void Foo() {
-   wxFile file;
-
-// wxFile.Open() normally complains if file can't be opened, we don't want it
-wxLogNull logNo;
-if ( !file.Open("bar") )
-... process error ourselves ...
-
-// ~wxLogNull called, old log sink restored
-}
- */
-class WXDLLEXPORT wxLogNull
-{
-public:
-    wxLogNull() { m_flagOld = wxLog::EnableLogging(FALSE); }
-    ~wxLogNull() { (void)wxLog::EnableLogging(m_flagOld);   }
-
-private:
-    bool m_flagOld; // the previous value of the wxLog::ms_doLog
-};
-
 // ============================================================================
 // global functions
 // ============================================================================
@@ -418,12 +460,6 @@ private:
 // for log messages for easy redirection
 // ----------------------------------------------------------------------------
 
-// are we in 'verbose' mode?
-// (note that it's often handy to change this var manually from the
-//  debugger, thus enabling/disabling verbose reporting for some
-//  parts of the program only)
-WXDLLEXPORT_DATA(extern bool) g_bVerbose;
-
 // ----------------------------------------------------------------------------
 // get error code/error message from system in a portable way
 // ----------------------------------------------------------------------------