Fix for issue #278: Can we use the qt/kde file picker instead of gtk?

Under the X11 platform, class Fl_Native_File_Chooser will behave as follows :
- if the KDE desktop is used and if command "kdialog" is available in the path,
the Qt/KDE file chooser is used;
- otherwise, if the GTK library is available at run-time,
the GTK file chooser is used;
- otherwise, the FLTK file chooser is used.

In addition, when Fl::OPTION_FNFC_USES_GTK is off, the FLTK file chooser
is always used.

FL/Fl_Native_File_Chooser.H

@@ -27,7 +27,9 @@
 
         class Fl_Native_File_Chooser_FLTK_Driver   <== this API implementation is the default FLTK file chooser
                 class Fl_GTK_Native_File_Chooser_Driver  <== this API implementation runs a GTK file chooser
+                class Fl_Kdialog_Native_File_Chooser_Driver  <== this API implementation runs a KDE file chooser
                                         it is determined at run-time if the GTK dynamic libraries are available
+                                        and the KDE file chooser runs under the KDE desktop
 
         class Fl_Quartz_Native_File_Chooser_Driver  <== this API implementation runs a Mac OS X file chooser
 

src/CMakeLists.txt

@@ -213,6 +213,7 @@ if (USE_X11)
     fl_dnd_x.cxx
     Fl_Native_File_Chooser_FLTK.cxx
     Fl_Native_File_Chooser_GTK.cxx
+    Fl_Native_File_Chooser_Kdialog.cxx
     Fl_get_key.cxx
   )
   if (USE_XFT)

src/Fl_Native_File_Chooser_GTK.cxx

@@ -1,7 +1,7 @@
 //
 // FLTK native file chooser widget wrapper for GTK's GtkFileChooserDialog
 //
-// Copyright 1998-2018 by Bill Spitzak and others.
+// Copyright 1998-2021 by Bill Spitzak and others.
 // Copyright 2012 IMM
 //
 // This library is free software. Distribution and use rights are outlined in
@@ -17,6 +17,7 @@
 
 #include <config.h>
 #include <FL/Fl_Native_File_Chooser.H>
+#include "Fl_Native_File_Chooser_Kdialog.H"
 
 #if HAVE_DLSYM && HAVE_DLFCN_H
 #include <FL/platform.H>
@@ -907,17 +908,38 @@ void Fl_GTK_Native_File_Chooser_Driver::probe_for_GTK_libs(void) {
 #endif // HAVE_DLSYM && HAVE_DLFCN_H
 
 Fl_Native_File_Chooser::Fl_Native_File_Chooser(int val) {
+  // Use kdialog if available at run-time and if using the KDE desktop,
+  // else, use GTK dialog if available at run-time
+  // otherwise, use FLTK file chooser.
+  platform_fnfc = NULL;
+  if (Fl::option(Fl::OPTION_FNFC_USES_GTK)) {
+    const char *desktop = getenv("XDG_CURRENT_DESKTOP");
+    if (desktop && strcmp(desktop, "KDE") == 0) {
+      if (!Fl_Kdialog_Native_File_Chooser_Driver::have_looked_for_kdialog) {
+        // First Time here, try to find kdialog
+        FILE *pipe = popen("kdialog -v 2> /dev/null", "r");
+        if (pipe) {
+          char line[100] = "";
+          fgets(line, sizeof(line), pipe);
+          if (strlen(line) > 0) Fl_Kdialog_Native_File_Chooser_Driver::did_find_kdialog = true;
+          pclose(pipe);
+        }
+        Fl_Kdialog_Native_File_Chooser_Driver::have_looked_for_kdialog = true;
+      }
+      // if we found kdialog, we will use the Fl_Kdialog_Native_File_Chooser_Driver
+      if (Fl_Kdialog_Native_File_Chooser_Driver::did_find_kdialog) platform_fnfc = new Fl_Kdialog_Native_File_Chooser_Driver(val);
+    }
 #if HAVE_DLSYM && HAVE_DLFCN_H
+    if (!platform_fnfc) {
       if ( Fl_GTK_Native_File_Chooser_Driver::have_looked_for_GTK_libs == 0) {
         // First Time here, try to find the GTK libs if they are installed
-    if (Fl::option(Fl::OPTION_FNFC_USES_GTK)) {
         Fl_GTK_Native_File_Chooser_Driver::probe_for_GTK_libs();
-    }
         Fl_GTK_Native_File_Chooser_Driver::have_looked_for_GTK_libs = -1;
       }
       // if we found all the GTK functions we need, we will use the GtkFileChooserDialog
       if (Fl_GTK_Native_File_Chooser_Driver::did_find_GTK_libs) platform_fnfc = new Fl_GTK_Native_File_Chooser_Driver(val);
-  else
-#endif // HAVE_DLSYM && HAVE_DLFCN_H
-    platform_fnfc = new Fl_Native_File_Chooser_FLTK_Driver(val);
+    }
+#endif // HAVE_DLSYM && HAVE_DLFCN_H
+  }
+  if (!platform_fnfc) platform_fnfc = new Fl_Native_File_Chooser_FLTK_Driver(val);
 }

src/Fl_Native_File_Chooser_Kdialog.H

@@ -0,0 +1,49 @@
+//
+// FLTK native file chooser widget : KDE version
+//
+// Copyright 2021 by Bill Spitzak and others.
+//
+// This library is free software. Distribution and use rights are outlined in
+// the file "COPYING" which should have been included with this file.  If this
+// file is missing or damaged, see the license at:
+//
+//     https://www.fltk.org/COPYING.php
+//
+// Please see the following page on how to report bugs and issues:
+//
+//     https://www.fltk.org/bugs.php
+//
+
+#ifndef FL_KDIALOG_NATIVE_FILE_CHOOSER_H
+#define FL_KDIALOG_NATIVE_FILE_CHOOSER_H 1
+
+#include <FL/Fl_Native_File_Chooser.H>
+
+class FL_EXPORT Fl_Kdialog_Native_File_Chooser_Driver : public Fl_Native_File_Chooser_FLTK_Driver {
+  friend class Fl_Native_File_Chooser;
+  char **_pathnames;
+  int _tpathnames;
+  char *_directory;
+  char *_preset_file;
+  char *_title;
+  static bool did_find_kdialog;
+  static bool have_looked_for_kdialog;
+  Fl_Kdialog_Native_File_Chooser_Driver(int val);
+  ~Fl_Kdialog_Native_File_Chooser_Driver();
+  int count() const;
+  const char *filename() const;
+  const char *filename(int i) const;
+  int show();
+  char *parse_filter(const char *f);
+  const char *filter() const;
+  virtual void filter(const char *f);
+  int filters() const;
+  void preset_file(const char *val);
+  const char *preset_file() const;
+  void directory(const char *val);
+  const char *directory() const;
+  void title(const char *val);
+  const char *title() const;
+};
+
+#endif // FL_KDIALOG_NATIVE_FILE_CHOOSER_H

src/Fl_Native_File_Chooser_Kdialog.cxx

@@ -0,0 +1,229 @@
+//
+// FLTK native file chooser widget : KDE version
+//
+// Copyright 2021 by Bill Spitzak and others.
+//
+// This library is free software. Distribution and use rights are outlined in
+// the file "COPYING" which should have been included with this file.  If this
+// file is missing or damaged, see the license at:
+//
+//     https://www.fltk.org/COPYING.php
+//
+// Please see the following page on how to report bugs and issues:
+//
+//     https://www.fltk.org/bugs.php
+//
+
+#include <config.h>
+#include <FL/Fl_Native_File_Chooser.H>
+#include "Fl_Native_File_Chooser_Kdialog.H"
+
+#include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
+
+
+/* Fl_Kdialog_Native_File_Chooser_Driver : file chooser based on the "kdialog" command */
+
+bool Fl_Kdialog_Native_File_Chooser_Driver::did_find_kdialog = false;
+bool Fl_Kdialog_Native_File_Chooser_Driver::have_looked_for_kdialog = false;
+
+
+Fl_Kdialog_Native_File_Chooser_Driver::Fl_Kdialog_Native_File_Chooser_Driver(int val) :  Fl_Native_File_Chooser_FLTK_Driver(val) {
+  _tpathnames = 0;
+  _pathnames = NULL;
+  _directory = NULL;
+  _preset_file = NULL;
+  _title = NULL;
+}
+
+
+Fl_Kdialog_Native_File_Chooser_Driver::~Fl_Kdialog_Native_File_Chooser_Driver() {
+  for (int i = 0; i < _tpathnames; i++) delete[] _pathnames[i];
+  delete[] _pathnames;
+  if (_preset_file) free(_preset_file);
+  if (_directory) free(_directory);
+  if (_title) free(_title);
+}
+
+
+int Fl_Kdialog_Native_File_Chooser_Driver::show() {
+  Fl::flush(); // to close menus if necessary
+  const char *option;
+  switch (_btype) {
+    case Fl_Native_File_Chooser::BROWSE_DIRECTORY:
+    case Fl_Native_File_Chooser::BROWSE_MULTI_DIRECTORY: // not supported
+      option = "--getexistingdirectory";
+      break;
+
+    case Fl_Native_File_Chooser::BROWSE_SAVE_FILE:
+    case Fl_Native_File_Chooser::BROWSE_SAVE_DIRECTORY:
+      option = "--getsavefilename";
+      break;
+
+    case Fl_Native_File_Chooser::BROWSE_MULTI_FILE:
+      option = "--multiple --getopenfilename";
+      break;
+
+    default:
+      option = "--getopenfilename";
+  }
+  const char *preset = ".";
+  if (_preset_file) preset = _preset_file;
+  else if (_directory) preset = _directory;
+  char *command = new char[strlen(option) + strlen(preset) + (_title?strlen(_title)+11:0) +
+                           (_parsedfilt?strlen(_parsedfilt):0) + 50];
+  strcpy(command, "kdialog ");
+  if (_title) {
+    sprintf(command+strlen(command), " --title '%s'", _title);
+  }
+  sprintf(command+strlen(command), " %s %s ", option, preset);
+  if (_parsedfilt) sprintf(command+strlen(command), " \"%s\" ", _parsedfilt);
+  strcat(command, "2> /dev/null"); // get rid of stderr output
+//puts(command);
+  FILE *pipe = popen(command, "r");
+  char *all_files = NULL;
+  if (pipe) {
+    char *p, tmp[FL_PATH_MAX];
+    do {
+      p = fgets(tmp, sizeof(tmp), pipe);
+      if (p) all_files = strapp(all_files, p);
+    }
+    while (p);
+    pclose(pipe);
+    if (all_files) {
+      if (all_files[strlen(all_files)-1] == '\n') all_files[strlen(all_files)-1] = 0;
+      for (int i = 0; i < _tpathnames; i++) delete[] _pathnames[i];
+      delete[] _pathnames;
+      p = all_files;
+      int count = 1;
+      while ((p = strchr(p+1, ' '))) count++;
+      _pathnames = new char*[count];
+      _tpathnames = 0;
+      char *q = strtok(all_files, " ");
+      while (q) {
+        _pathnames[_tpathnames] = new char[strlen(q)+1];
+        strcpy(_pathnames[_tpathnames], q);
+        _tpathnames++;
+        q = strtok(NULL, " ");
+      }
+    }
+  }
+  delete[] command;
+  if (_title) { free(_title); _title = NULL; }
+  if (!pipe) return -1;
+  return (all_files == NULL ? 1 : 0);
+}
+
+
+const char *Fl_Kdialog_Native_File_Chooser_Driver::filename() const {
+  return _tpathnames >= 1 ? _pathnames[0] : NULL;
+}
+
+const char *Fl_Kdialog_Native_File_Chooser_Driver::filename (int i) const {
+  return _tpathnames > i ? _pathnames[i] : NULL;
+}
+
+const char *Fl_Kdialog_Native_File_Chooser_Driver::filter() const  {
+  return _filter;
+}
+
+int Fl_Kdialog_Native_File_Chooser_Driver::filters() const {
+  return (_nfilters ? _nfilters - 1 : 0);
+}
+
+int Fl_Kdialog_Native_File_Chooser_Driver::count() const {
+  return _tpathnames;
+}
+
+char *Fl_Kdialog_Native_File_Chooser_Driver::parse_filter(const char *f) {
+  //In: "*.H\n" or "*.H"        Out: "(*.H)"
+  //In: "Headers\t*.H\n"        Out: "Headers (*.H)"
+  //In: "Headers\t*.{H,h}\n"    Out: "Headers (*.H *.h)"
+  const char *p = strchr(f, '\t');
+  if (!p) p = f - 1;
+  const char *q = strchr(f, '\n'); if (!q) q = f + strlen(f);
+  const char *r = strchr(f, '{');
+  char *developed = NULL;
+  if (r) { // with {}
+    char *lead = new char[r-p];
+    memcpy(lead, p+1, (r-p)-1); lead[(r-p)-1] = 0;
+    const char *r2 = strchr(r, '}');
+    char *ends = new char[r2-r];
+    memcpy(ends, r+1, (r2-r)-1); ends[(r2-r)-1] = 0;
+    char *ptr;
+    char *part = strtok_r(ends, ",", &ptr);
+    while (part) {
+      developed = strapp(developed, lead);
+      developed = strapp(developed, part);
+      developed = strapp(developed, " ");
+      part = strtok_r(NULL, ",", &ptr);
+    }
+    if (developed[strlen(developed)-1] == ' ') developed[strlen(developed)-1] = 0;
+    delete[] lead;
+    delete[] ends;
+  }
+  int lout = (p>f?p-f:0) + 2 + (r?strlen(developed):((q-p)-1)) + 2;
+  char *out = new char[lout]; *out = 0;
+  if (p > f) {memcpy(out, f, p-f); out[p-f] = 0; }
+  strcat(out, " (");
+  if (r) {
+    strcpy(out+strlen(out), developed);
+    strfree(developed);
+  }
+  else memcpy(out+strlen(out), p+1, (q-p));
+  strcat(out, ")");
+//puts(out);
+  return out;
+}
+
+
+void Fl_Kdialog_Native_File_Chooser_Driver::filter(const char *f) {
+  _parsedfilt = strfree(_parsedfilt);   // clear previous parsed filter (if any)
+  _nfilters = 0;
+  if (!f) return;
+  _filter = strdup(f);
+  char *f2 = strdup(f);
+  char *ptr;
+  char *part = strtok_r(f2, "\n", &ptr);
+  while (part) {
+    char *p = parse_filter(part);
+    _parsedfilt = strapp(_parsedfilt, p);
+    _parsedfilt = strapp(_parsedfilt, "\\n");
+    delete[] p;
+    _nfilters++;
+    part = strtok_r(NULL, "\n", &ptr);
+  }
+  free(f2);
+  _parsedfilt = strapp(_parsedfilt, "All files (*)");
+  _nfilters++;
+//puts(_parsedfilt);
+}
+
+void Fl_Kdialog_Native_File_Chooser_Driver::preset_file(const char *val) {
+  if (_preset_file) free(_preset_file);
+  _preset_file = strdup(val);
+}
+
+const char *Fl_Kdialog_Native_File_Chooser_Driver::preset_file() const {
+  return _preset_file;
+}
+
+void Fl_Kdialog_Native_File_Chooser_Driver::directory(const char *val) {
+  if (_directory) free(_directory);
+  _directory = strdup(val);
+}
+
+const char *Fl_Kdialog_Native_File_Chooser_Driver::directory() const {
+  return _directory;
+}
+
+void Fl_Kdialog_Native_File_Chooser_Driver::title(const char *val)
+{
+  if (_title) free(_title);
+  _title = strdup(val);
+}
+
+const char *Fl_Kdialog_Native_File_Chooser_Driver::title() const {
+  return _title;
+}

src/Makefile

@@ -268,6 +268,7 @@ XLIBCPPFILES = \
 	fl_dnd_x.cxx \
         Fl_Native_File_Chooser_FLTK.cxx \
 	Fl_Native_File_Chooser_GTK.cxx\
+	Fl_Native_File_Chooser_Kdialog.cxx \
         Fl_get_key.cxx
 
 # This C file is used under condition: BUILD_X11