improve wxMessageOutputBest console output under Windows (closes 9146)

git-svn-id: https://svn.wxwidgets.org/svn/wx/wxWidgets/trunk@53730 c3d73ce0-8a6f-49c7-b76d-6d57e0e08775

include/wx/msgout.h

@@ -100,21 +100,6 @@ private:
     #pragma warning (default:4275)
 #endif
 
-// ----------------------------------------------------------------------------
-// implementation showing the message to the user in "best" possible way: uses
-// native message box if available (currently only under Windows) and stderr
-// otherwise; unlike wxMessageOutputMessageBox this class is always safe to use
-// ----------------------------------------------------------------------------
-
-class WXDLLIMPEXP_BASE wxMessageOutputBest : public wxMessageOutput
-{
-public:
-    wxMessageOutputBest() { }
-
-protected:
-    virtual void Output(const wxString& str);
-};
-
 // ----------------------------------------------------------------------------
 // implementation which sends output to stderr
 // ----------------------------------------------------------------------------
@@ -126,6 +111,34 @@ public:
 
 protected:
     virtual void Output(const wxString& str);
+
+    // return the string with "\n" appended if it doesn't already terminate
+    // with it (in which case it's returned unchanged)
+    wxString AppendLineFeedIfNeeded(const wxString& str);
+};
+
+// ----------------------------------------------------------------------------
+// implementation showing the message to the user in "best" possible way:
+// uses stderr or message box if available according to the flag given to ctor.
+// ----------------------------------------------------------------------------
+
+enum wxMessageOutputFlags
+{
+    wxMSGOUT_PREFER_STDERR = 0, // use stderr if available (this is the default)
+    wxMSGOUT_PREFER_MSGBOX = 1  // always use message box if available
+};
+
+class WXDLLIMPEXP_BASE wxMessageOutputBest : public wxMessageOutputStderr
+{
+public:
+    wxMessageOutputBest(wxMessageOutputFlags flags = wxMSGOUT_PREFER_STDERR)
+        : m_flags(flags) { }
+
+protected:
+    virtual void Output(const wxString& str);
+
+private:
+    wxMessageOutputFlags m_flags;
 };
 
 // ----------------------------------------------------------------------------
@@ -149,7 +162,7 @@ protected:
 // implementation using the native way of outputting debug messages
 // ----------------------------------------------------------------------------
 
-class WXDLLIMPEXP_BASE wxMessageOutputDebug : public wxMessageOutput
+class WXDLLIMPEXP_BASE wxMessageOutputDebug : public wxMessageOutputStderr
 {
 public:
     wxMessageOutputDebug() { }
@@ -171,5 +184,4 @@ protected:
     virtual void Output(const wxString& str);
 };
 
-#endif
+#endif // _WX_MSGOUT_H_
-    // _WX_MSGOUT_H_

include/wx/msw/apptbase.h

@@ -65,6 +65,23 @@ public:
     virtual GSocketManager *GetSocketManager() { return ms_manager; }
 #endif // wxUSE_SOCKETS
 
+
+#ifndef __WXWINCE__
+    // console helpers
+    // ---------------
+
+    // this method can be overridden by a derived class to always return true
+    // or false to force [not] using the console for output to stderr
+    //
+    // by default console applications always return true from here while the
+    // GUI ones only return true if they're being run from console and there is
+    // no other activity happening in this console
+    virtual bool CanUseStderr() = 0;
+
+    // write text to the console, return true if ok or false on error
+    virtual bool WriteToStderr(const wxString& text) = 0;
+#endif // !__WXWINCE__
+
 protected:
     // implementation of WaitForThread() for the console applications which is
     // also used by the GUI code if it doesn't [yet|already} dispatch events

include/wx/msw/apptrait.h

@@ -28,6 +28,10 @@ public:
 #endif
     virtual bool DoMessageFromThreadWait();
     virtual WXDWORD WaitForThread(WXHANDLE hThread);
+#ifndef __WXWINCE__
+    virtual bool CanUseStderr() { return true; }
+    virtual bool WriteToStderr(const wxString& text);
+#endif // !__WXWINCE__
 };
 
 #if wxUSE_GUI
@@ -45,9 +49,13 @@ public:
     virtual bool DoMessageFromThreadWait();
     virtual wxPortId GetToolkitVersion(int *majVer = NULL, int *minVer = NULL) const;
     virtual WXDWORD WaitForThread(WXHANDLE hThread);
+
+#ifndef __WXWINCE__
+    virtual bool CanUseStderr();
+    virtual bool WriteToStderr(const wxString& text);
+#endif // !__WXWINCE__
 };
 
 #endif // wxUSE_GUI
 
 #endif // _WX_MSW_APPTRAIT_H_
-

src/common/appcmn.cpp

@@ -437,7 +437,8 @@ wxMessageOutput *wxGUIAppTraitsBase::CreateMessageOutput()
     // is (according to common practice):
     //     - console apps: to stderr (on any platform)
     //     - GUI apps: stderr on Unix platforms (!)
-    //                 message box under Windows and others
+    //                 stderr if available and message box otherwise on others
+    //                 (currently stderr only Windows if app running from console)
 #ifdef __UNIX__
     return new wxMessageOutputStderr;
 #else // !__UNIX__
@@ -445,7 +446,7 @@ wxMessageOutput *wxGUIAppTraitsBase::CreateMessageOutput()
     #ifdef __WXMOTIF__
         return new wxMessageOutputLog;
     #elif wxUSE_MSGDLG
-        return new wxMessageOutputMessageBox;
+        return new wxMessageOutputBest(wxMSGOUT_PREFER_STDERR);
     #else
         return new wxMessageOutputStderr;
     #endif

src/common/msgout.cpp

@@ -105,48 +105,42 @@ void wxMessageOutput::DoPrintfUtf8(const char *format, ...)
 // wxMessageOutputBest
 // ----------------------------------------------------------------------------
 
-#ifdef __WINDOWS__
-
-// check if we're running in a console under Windows
-static inline bool IsInConsole()
-{
-#ifdef __WXWINCE__
-    return false;
-#else // !__WXWINCE__
-    HANDLE hStdErr = ::GetStdHandle(STD_ERROR_HANDLE);
-    return hStdErr && hStdErr != INVALID_HANDLE_VALUE;
-#endif // __WXWINCE__/!__WXWINCE__
-}
-
-#endif // __WINDOWS__
-
 void wxMessageOutputBest::Output(const wxString& str)
 {
 #ifdef __WINDOWS__
-    if ( !IsInConsole() )
+    // decide whether to use console output or not
-    {
+    wxAppTraits * const traits = wxTheApp ? wxTheApp->GetTraits() : NULL;
-        ::MessageBox(NULL, str.wx_str(), _T("wxWidgets"),
+    const bool hasStderr = traits ? traits->CanUseStderr() : false;
-                     MB_ICONINFORMATION | MB_OK);
-    }
-    else
-#endif // __WINDOWS__/!__WINDOWS__
-    {
-        const wxWX2MBbuf buf = str.mb_str();
 
-        if ( buf )
+    if ( !(m_flags & wxMSGOUT_PREFER_MSGBOX) )
-            fprintf(stderr, "%s", (const char*) buf);
+    {
-        else // print at least something
+        if ( hasStderr && traits->WriteToStderr(AppendLineFeedIfNeeded(str)) )
-            fprintf(stderr, "%s", (const char*) str.ToAscii());
+            return;
     }
+
+    ::MessageBox(NULL, str.wx_str(), NULL, MB_ICONINFORMATION | MB_OK);
+#else // !__WINDOWS__
+    // TODO: use the native message box for the other ports too
+    wxMessageOutputStderr::Output(str);
+#endif // __WINDOWS__/!__WINDOWS__
 }
 
 // ----------------------------------------------------------------------------
 // wxMessageOutputStderr
 // ----------------------------------------------------------------------------
 
+wxString wxMessageOutputStderr::AppendLineFeedIfNeeded(const wxString& str)
+{
+    wxString strLF(str);
+    if ( strLF.empty() || *strLF.rbegin() != '\n' )
+        strLF += '\n';
+
+    return strLF;
+}
+
 void wxMessageOutputStderr::Output(const wxString& str)
 {
-    const wxWX2MBbuf buf = str.mb_str();
+    const wxWX2MBbuf buf = AppendLineFeedIfNeeded(str).mb_str();
 
     if ( buf )
         fprintf(stderr, "%s", (const char*) buf);
@@ -160,17 +154,14 @@ void wxMessageOutputStderr::Output(const wxString& str)
 
 void wxMessageOutputDebug::Output(const wxString& str)
 {
-    wxString out(str);
-
 #if defined(__WXMSW__) && !defined(__WXMICROWIN__)
+    wxString out(AppendLineFeedIfNeeded(str));
     out.Replace(wxT("\t"), wxT("        "));
     out.Replace(wxT("\n"), wxT("\r\n"));
     ::OutputDebugString(out.wx_str());
 #else
-    wxFputs( out , stderr ) ;
+    // TODO: use native debug output function for the other ports too
-    if ( out.Right(1) != wxT("\n") )
+    wxMessageOutputStderr::Output(str);
-        wxFputs( wxT("\n") , stderr ) ;
-    fflush( stderr ) ;
 #endif // platform
 }
 
@@ -204,9 +195,7 @@ void wxMessageOutputMessageBox::Output(const wxString& str)
     out.Replace(wxT("\t"), wxT("        "));
 #endif
 
-    wxString title;
+    wxString title = wxTheApp ? wxTheApp->GetAppDisplayName() : wxT("wxWidgets");
-    if ( wxTheApp )
-        title.Printf(_("%s message"), wxTheApp->GetAppDisplayName().c_str());
 
     ::wxMessageBox(out, title);
 }

src/msw/app.cpp

@@ -282,6 +282,279 @@ wxEventLoopBase* wxGUIAppTraits::CreateEventLoop()
     return new wxEventLoop;
 }
 
+// ---------------------------------------------------------------------------
+// Stuff for using console from the GUI applications
+// ---------------------------------------------------------------------------
+
+#ifndef __WXWINCE__
+
+#include <wx/dynlib.h>
+
+namespace
+{
+
+/*
+    Helper class to manipulate console from a GUI app.
+
+    Notice that console output is available in the GUI app only if:
+    - AttachConsole() returns TRUE (which means it never works under pre-XP)
+    - we have a valid STD_ERROR_HANDLE
+    - command history hasn't been changed since our startup
+
+    To check if all these conditions are verified, you need to simple call
+    IsOkToUse(). It will check the first two conditions above the first time it
+    is called (and if this fails, the subsequent calls will return immediately)
+    and also recheck the last one every time it is called.
+ */
+class wxConsoleStderr
+{
+public:
+    // default ctor does nothing, call Init() before using this class
+    wxConsoleStderr()
+    {
+        m_hStderr = INVALID_HANDLE_VALUE;
+        m_historyLen =
+        m_dataLen =
+        m_dataLine = 0;
+
+        m_ok = -1;
+    }
+
+    ~wxConsoleStderr()
+    {
+        if ( m_hStderr != INVALID_HANDLE_VALUE )
+        {
+            if ( !::FreeConsole() )
+            {
+                wxLogLastError(_T("FreeConsole"));
+            }
+        }
+    }
+
+    // return true if we were successfully initialized and there had been no
+    // console activity which would interfere with our output since then
+    bool IsOkToUse() const
+    {
+        if ( m_ok == -1 )
+        {
+            wxConsoleStderr * const self = wx_const_cast(wxConsoleStderr *, this);
+            self->m_ok = self->DoInit();
+
+            // no need to call IsHistoryUnchanged() as we just initialized
+            // m_history anyhow
+            return m_ok == 1;
+        }
+
+        return m_ok && IsHistoryUnchanged();
+    }
+
+
+    // output the provided text on the console, return true if ok
+    bool Write(const wxString& text);
+
+private:
+    // called by Init() once only to do the real initialization
+    bool DoInit();
+
+    // retrieve the command line history into the provided buffer and return
+    // its length
+    int GetCommandHistory(wxWxCharBuffer& buf) const;
+
+    // check if the console history has changed
+    bool IsHistoryUnchanged() const;
+
+    int m_ok;                   // initially -1, set to true or false by Init()
+
+    wxDynamicLibrary m_dllKernel32;
+
+    HANDLE m_hStderr;           // console handle, if it's valid we must call
+                                // FreeConsole() (even if m_ok != 1)
+
+    wxWxCharBuffer m_history;   // command history on startup
+    int m_historyLen;           // length command history buffer
+
+    wxCharBuffer m_data;        // data between empty line and cursor position
+    int m_dataLen;              // length data buffer
+    int m_dataLine;             // line offset
+
+    typedef DWORD (WINAPI *GetConsoleCommandHistory_t)(LPTSTR sCommands,
+                                                       DWORD nBufferLength,
+                                                       LPCTSTR sExeName);
+    typedef DWORD (WINAPI *GetConsoleCommandHistoryLength_t)(LPCTSTR sExeName);
+
+    GetConsoleCommandHistory_t m_pfnGetConsoleCommandHistory;
+    GetConsoleCommandHistoryLength_t m_pfnGetConsoleCommandHistoryLength;
+
+    DECLARE_NO_COPY_CLASS(wxConsoleStderr)
+};
+
+bool wxConsoleStderr::DoInit()
+{
+    HANDLE hStderr = ::GetStdHandle(STD_ERROR_HANDLE);
+
+    if ( hStderr == INVALID_HANDLE_VALUE || !hStderr )
+        return false;
+
+    if ( !m_dllKernel32.Load(_T("kernel32.dll")) )
+        return false;
+
+    typedef BOOL (WINAPI *AttachConsole_t)(DWORD dwProcessId);
+    AttachConsole_t wxDL_INIT_FUNC(pfn, AttachConsole, m_dllKernel32);
+
+    if ( !pfnAttachConsole || !pfnAttachConsole(ATTACH_PARENT_PROCESS) )
+        return false;
+
+    // console attached, set m_hStderr now to ensure that we free it in the
+    // dtor
+    m_hStderr = hStderr;
+
+    wxDL_INIT_FUNC_AW(m_pfn, GetConsoleCommandHistory, m_dllKernel32);
+    if ( !m_pfnGetConsoleCommandHistory )
+        return false;
+
+    wxDL_INIT_FUNC_AW(m_pfn, GetConsoleCommandHistoryLength, m_dllKernel32);
+    if ( !m_pfnGetConsoleCommandHistoryLength )
+        return false;
+
+    // remember the current command history to be able to compare with it later
+    // in IsHistoryUnchanged()
+    m_historyLen = GetCommandHistory(m_history);
+    if ( !m_history )
+        return false;
+
+
+    // now find the first blank line above the current position
+    CONSOLE_SCREEN_BUFFER_INFO csbi;
+
+    if ( !::GetConsoleScreenBufferInfo(m_hStderr, &csbi) )
+    {
+        wxLogLastError(_T("GetConsoleScreenBufferInfo"));
+        return false;
+    }
+
+    COORD pos;
+    pos.X = 0;
+    pos.Y = csbi.dwCursorPosition.Y + 1;
+
+    // we decide that a line is empty if first 4 characters are spaces
+    DWORD ret;
+    char buf[4];
+    do
+    {
+        pos.Y--;
+        if ( !::ReadConsoleOutputCharacterA(m_hStderr, buf, WXSIZEOF(buf),
+                                            pos, &ret) )
+        {
+            wxLogLastError(_T("ReadConsoleOutputCharacterA"));
+            return false;
+        }
+    } while ( wxStrncmp("    ", buf, WXSIZEOF(buf)) != 0 );
+
+    // calculate line offset and length of data
+    m_dataLine = csbi.dwCursorPosition.Y - pos.Y;
+    m_dataLen = m_dataLine*csbi.dwMaximumWindowSize.X + csbi.dwCursorPosition.X;
+
+    if ( m_dataLen > 0 )
+    {
+        m_data.extend(m_dataLen);
+        if ( !::ReadConsoleOutputCharacterA(m_hStderr, m_data.data(), m_dataLen,
+                                            pos, &ret) )
+        {
+            wxLogLastError(_T("ReadConsoleOutputCharacterA"));
+            return false;
+        }
+    }
+
+    return true;
+}
+
+int wxConsoleStderr::GetCommandHistory(wxWxCharBuffer& buf) const
+{
+    // these functions are internal and may only be called by cmd.exe
+    static const wxChar *CMD_EXE = _T("cmd.exe");
+
+    const int len = m_pfnGetConsoleCommandHistoryLength(CMD_EXE);
+    if ( len )
+    {
+        buf.extend(len);
+        const int len2 = m_pfnGetConsoleCommandHistory(buf.data(), len, CMD_EXE);
+        wxASSERT_MSG( len2 == len, _T("failed getting history?") );
+    }
+
+    return len;
+}
+
+bool wxConsoleStderr::IsHistoryUnchanged() const
+{
+    wxASSERT_MSG( m_ok == 1, _T("shouldn't be called if not initialized") );
+
+    // get (possibly changed) command history
+    wxWxCharBuffer history;
+    const int historyLen = GetCommandHistory(history);
+
+    // and compare it with the original one
+    return historyLen == m_historyLen && history &&
+                memcmp(m_history, history, historyLen) == 0;
+}
+
+bool wxConsoleStderr::Write(const wxString& text)
+{
+    wxASSERT_MSG( m_hStderr != INVALID_HANDLE_VALUE,
+                    _T("should only be called if Init() returned true") );
+
+    // get current position
+    CONSOLE_SCREEN_BUFFER_INFO csbi;
+    if ( !::GetConsoleScreenBufferInfo(m_hStderr, &csbi) )
+    {
+        wxLogLastError(_T("GetConsoleScreenBufferInfo"));
+        return false;
+    }
+
+    // and calculate new position (where is empty line)
+    csbi.dwCursorPosition.X = 0;
+    csbi.dwCursorPosition.Y -= m_dataLine;
+
+    if ( !::SetConsoleCursorPosition(m_hStderr, csbi.dwCursorPosition) )
+    {
+        wxLogLastError(_T("SetConsoleCursorPosition"));
+        return false;
+    }
+
+    DWORD ret;
+    if ( !::FillConsoleOutputCharacter(m_hStderr, _T(' '), m_dataLen,
+                                       csbi.dwCursorPosition, &ret) )
+    {
+        wxLogLastError(_T("FillConsoleOutputCharacter"));
+        return false;
+    }
+
+    if ( !::WriteConsole(m_hStderr, text.wx_str(), text.length(), &ret, NULL) )
+    {
+        wxLogLastError(_T("WriteConsole"));
+        return false;
+    }
+
+    WriteConsoleA(m_hStderr, m_data, m_dataLen, &ret, 0);
+
+    return true;
+}
+
+wxConsoleStderr s_consoleStderr;
+
+} // anonymous namespace
+
+bool wxGUIAppTraits::CanUseStderr()
+{
+    return s_consoleStderr.IsOkToUse();
+}
+
+bool wxGUIAppTraits::WriteToStderr(const wxString& text)
+{
+    return s_consoleStderr.IsOkToUse() && s_consoleStderr.Write(text);
+}
+
+#endif // !__WXWINCE__
+
 // ===========================================================================
 // wxApp implementation
 // ===========================================================================

src/msw/basemsw.cpp

@@ -108,3 +108,7 @@ WXDWORD wxConsoleAppTraits::WaitForThread(WXHANDLE hThread)
     return DoSimpleWaitForThread(hThread);
 }
 
+bool wxConsoleAppTraits::WriteToStderr(const wxString& text)
+{
+    return wxFprintf(stderr, "%s", text) != -1;
+}