Improve kdialog-based native file chooser.

Processing of all FLTK events as well as window resizing while the file chooser runs is suspended,
Normal event processing and resizing is restored when chooser closes.

2 files changed, 74 insertions, 15 deletions

diff --git a/src/Fl_Native_File_Chooser_Kdialog.H b/src/Fl_Native_File_Chooser_Kdialog.H
index 730b25e29..f73242ca6 100644
--- a/src/Fl_Native_File_Chooser_Kdialog.H
+++ b/src/Fl_Native_File_Chooser_Kdialog.H
@@ -1,7 +1,7 @@
 //
 // FLTK native file chooser widget : KDE version
 //
-// Copyright 2021 by Bill Spitzak and others.
+// Copyright 2021-2022 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
@@ -21,6 +21,11 @@
 
 class FL_EXPORT Fl_Kdialog_Native_File_Chooser_Driver : public Fl_Native_File_Chooser_FLTK_Driver {
   friend class Fl_Native_File_Chooser;
+  struct fnfc_pipe_struct {
+    char *all_files;
+    int fd;
+  };
+  static void fnfc_fd_cb(int fd, fnfc_pipe_struct *data);
   char **_pathnames;
   int _tpathnames;
   char *_directory;
diff --git a/src/Fl_Native_File_Chooser_Kdialog.cxx b/src/Fl_Native_File_Chooser_Kdialog.cxx
index 6f2298bb1..368a2b6ed 100644
--- a/src/Fl_Native_File_Chooser_Kdialog.cxx
+++ b/src/Fl_Native_File_Chooser_Kdialog.cxx
@@ -1,7 +1,7 @@
 //
 // FLTK native file chooser widget : KDE version
 //
-// Copyright 2021 by Bill Spitzak and others.
+// Copyright 2021-2022 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
@@ -17,10 +17,11 @@
 #include <config.h>
 #include <FL/Fl_Native_File_Chooser.H>
 #include "Fl_Native_File_Chooser_Kdialog.H"
-
+#include "Fl_Window_Driver.H"
 #include <stdio.h>
 #include <stdlib.h>
 #include <string.h>
+#include <unistd.h>
 
 
 /* Fl_Kdialog_Native_File_Chooser_Driver : file chooser based on the "kdialog" command */
@@ -47,8 +48,25 @@ Fl_Kdialog_Native_File_Chooser_Driver::~Fl_Kdialog_Native_File_Chooser_Driver()
 }
 
 
+void Fl_Kdialog_Native_File_Chooser_Driver::fnfc_fd_cb(int fd,
+                      Fl_Kdialog_Native_File_Chooser_Driver::fnfc_pipe_struct *data) {
+  char tmp[FL_PATH_MAX];
+  int l = read(fd, tmp, sizeof(tmp)-1);
+  if (l > 0) {
+    tmp[l] = 0;
+    data->all_files = Fl_Native_File_Chooser_Driver::strapp(data->all_files, tmp);
+  } else {
+    data->fd = -1;
+  }
+}
+
+
+static int fnfc_dispatch(int /*event*/, Fl_Window* /*win*/) {
+  return 0;
+}
+
+
 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_MULTI_DIRECTORY: {
@@ -103,25 +121,61 @@ int Fl_Kdialog_Native_File_Chooser_Driver::show() {
   strcat(command, "2> /dev/null"); // get rid of stderr output
 //puts(command);
   FILE *pipe = popen(command, "r");
-  char *all_files = NULL;
+  fnfc_pipe_struct data;
+  data.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);
+    data.fd = fileno(pipe);
+    Fl::add_fd(data.fd, FL_READ, (Fl_FD_Handler)fnfc_fd_cb, &data);
+    Fl_Event_Dispatch old_dispatch = Fl::event_dispatch();
+    // prevent FLTK from processing any event
+    Fl::event_dispatch(fnfc_dispatch);
+    struct win_dims {
+      Fl_Window *win;
+      int minw,minh,maxw,maxh;
+      struct win_dims *next;
+    } *first_dim = NULL;
+    // consider all bordered, top-level FLTK windows
+    Fl_Window *win = Fl::first_window();
+    while (win) {
+      if (!win->parent() && win->border()) {
+        Fl_Window_Driver *dr = Fl_Window_Driver::driver(win);
+        win_dims *dim = new win_dims;
+        dim->win = win;
+        dim->minw = dr->minw();
+        dim->minh = dr->minh();
+        dim->maxw = dr->maxw();
+        dim->maxh = dr->maxh();
+        //make win un-resizable
+        win->size_range(win->w(), win->h(), win->w(), win->h());
+        dim->next = first_dim;
+        first_dim = dim;
+      }
+      win = Fl::next_window(win);
     }
-    while (p);
+    // run event loop until pipe finishes
+    while (data.fd >= 0) Fl::wait();
+    Fl::remove_fd(fileno(pipe));
     pclose(pipe);
-    if (all_files) {
-      if (all_files[strlen(all_files)-1] == '\n') all_files[strlen(all_files)-1] = 0;
+    // return to previous event processing by FLTK
+    Fl::event_dispatch(old_dispatch);
+    while (first_dim) {
+      win_dims *dim = first_dim;
+      //give back win its resizing parameters
+      dim->win->size_range(dim->minw, dim->minh, dim->maxw, dim->maxh);
+      first_dim = dim->next;
+      delete dim;
+    }
+    if (data.all_files) {
+      // process text received from pipe
+      if (data.all_files[strlen(data.all_files)-1] == '\n') data.all_files[strlen(data.all_files)-1] = 0;
       for (int i = 0; i < _tpathnames; i++) delete[] _pathnames[i];
       delete[] _pathnames;
-      p = all_files;
+      char *p = data.all_files;
       int count = 1;
       while ((p = strchr(p+1, ' '))) count++;
       _pathnames = new char*[count];
       _tpathnames = 0;
-      char *q = strtok(all_files, " ");
+      char *q = strtok(data.all_files, " ");
       while (q) {
         _pathnames[_tpathnames] = new char[strlen(q)+1];
         strcpy(_pathnames[_tpathnames], q);
@@ -133,7 +187,7 @@ int Fl_Kdialog_Native_File_Chooser_Driver::show() {
   delete[] command;
   if (_title) { free(_title); _title = NULL; }
   if (!pipe) return -1;
-  return (all_files == NULL ? 1 : 0);
+  return (data.all_files == NULL ? 1 : 0);
 }