Search and create MD5 for R3D using C

/* Brief:
 * This example using Gtk+-2.0 to create Find/Search for R3D files
 * in the given directory on Linux
 *
 * The output filename will be truncated to zero (if exist).
 * MD5 program on Linux is called 'md5sum', while on Mac OS X this program
 * called just 'md5'.
 *
 * It turns out that the output text file is not really needed, because
 * you can easily copy/paste the output text from the TextView, and save it
 * manually.
 *
 * To compile the program, use the following command:
 * gcc -o r3dsums r3dsums.c `pkg-config gtk+-2.0 --cflags --libs` -lobjc
 *
 * This example using Objective-C (without GNUstep/Cocoa)
 * But you can easily make it plain-C by altering the source.
 *
 */

#import <objc/runtime.h>
#import <gtk/gtk.h>
#import <stdio.h>
#import <stdlib.h>
#import <string.h>

@interface UITest {
  Class isa;
@private
  GtkWidget* window;
  GtkWidget* table;
  GtkWidget* textOutput;
  GtkWidget* textSource;
  GtkWidget* statusView;
}
@end

static void start_search(UITest* p);

@implementation UITest

-(id)initWithTitle:(const char*) pszTitle {
  window = gtk_window_new(GTK_WINDOW_TOPLEVEL);
  if (window) {
    GtkWindow* w = GTK_WINDOW(window);
    gtk_window_set_title(w, pszTitle);
    gtk_window_set_default_size(w, 640, 350);

    table = gtk_table_new(10, 2, FALSE);
    gtk_container_add(GTK_CONTAINER(window), table);

    GtkWidget* label = gtk_label_new("Source R3D Directory:");
    gtk_misc_set_alignment((GtkMisc*)label, 0.0, 0.5);
    gtk_table_attach((GtkTable*)table, label,
             0, 1,
             0, 1,
             GTK_EXPAND|GTK_FILL,
             GTK_SHRINK,
             5, 1);
    textSource = gtk_entry_new();
    gtk_table_attach((GtkTable*)table, textSource,
             0, 1,
             1, 2,
             GTK_EXPAND|GTK_FILL,
             GTK_SHRINK,
             5, 5);
    GtkWidget* btn = gtk_button_new_with_label("Browse");
    gtk_table_attach((GtkTable*)table, btn,
             1, 2,
             1, 2,
             GTK_FILL,
             GTK_SHRINK,
             5, 5);
    textOutput = gtk_entry_new();
    label = gtk_label_new("Output file name:");
    gtk_misc_set_alignment((GtkMisc*)label, 0.0, 0.5);
    gtk_table_attach((GtkTable*)table, label,
             0, 1,
             2, 3,
             GTK_EXPAND|GTK_FILL,
             GTK_SHRINK,
             5, 1);
    gtk_table_attach((GtkTable*)table, textOutput,
             0, 1,
             3, 4,
             GTK_EXPAND|GTK_FILL,
             GTK_SHRINK,
             5, 5);

    GtkWidget* sc = gtk_scrolled_window_new(NULL, NULL);
    statusView = gtk_text_view_new();
    gtk_container_add(GTK_CONTAINER(sc), statusView);
    gtk_table_attach((GtkTable*)table, sc,
             0, 2,
             4, 8,
             GTK_EXPAND|GTK_FILL,
             GTK_EXPAND|GTK_FILL,
             5, 5);

    GtkWidget* hbox = gtk_hbox_new(FALSE, 5);
    gtk_table_attach((GtkTable*)table, hbox,
             0, 2,
             8, 9,
             GTK_EXPAND|GTK_FILL,
             GTK_SHRINK,
             10, 10);

    btn = gtk_button_new_with_label("Start");
    gtk_box_pack_start((GtkBox*)hbox, btn, FALSE, TRUE, 1);
    g_signal_connect_swapped(btn, "clicked", G_CALLBACK(start_search), self);

    btn = gtk_button_new_with_label("Quit");
    gtk_box_pack_end((GtkBox*)hbox, btn, FALSE, TRUE, 1);
    g_signal_connect_swapped(btn, "clicked", G_CALLBACK(gtk_widget_destroy), window);

    gtk_widget_show_all(window);
    g_signal_connect(window, "destroy", G_CALLBACK(gtk_main_quit), NULL);
  }
  return self;
}

+(id)testWithTitle:(const char*) pszTitle {
  UITest* p = (UITest*)class_createInstance(self, 0);
  if (p) return [p initWithTitle:pszTitle];
  return NULL;
}

-(GtkTextBuffer*)bufferForOutput {
  return gtk_text_view_get_buffer(GTK_TEXT_VIEW(statusView));
}

-(const char*)pathForR3DSource {
  return gtk_entry_get_text(GTK_ENTRY(textSource));
}

-(const char*)outputFileName {
  return gtk_entry_get_text(GTK_ENTRY(textOutput));
}

@end

int main(int argc, char** argv) {
  gdk_threads_init();
  gtk_init(&argc, &argv);
  UITest* pObj = [UITest testWithTitle:"Object Test"];
  if (pObj) {
    gdk_threads_enter();
    gtk_main();
    gdk_threads_leave();
    free(pObj);
  }
  return 0;
}

static void* doSearch(UITest* p);

GThread* _searchThread = NULL;
static void start_search(UITest* p) {
  _searchThread = g_thread_new("__search_thread__",
                   (GThreadFunc)doSearch,
                   p);
}

static void* doSearch(UITest* p) {
  int pid;
  int fd[3];

  gdk_threads_enter();

  pipe(fd);
  pid = fork();
  if (pid < 0) {
    GtkTextBuffer* buffer = [p bufferForOutput];
    gtk_text_buffer_set_text(buffer, "fork error", -1);
    return (void*)0;
  }
  else if (pid == 0) {
    dup2(fd[1], STDOUT_FILENO);
    dup2(fd[2], STDERR_FILENO);
    close(fd[0]);
    close(fd[1]);
    execlp("/bin/find",
       "find",
       [p pathForR3DSource],
       "-type", "f",
       "-name", "*.R3D",
       "-exec", "md5sum", "{}", ";",
       NULL);
  }
  else {
    int status;
    GtkTextBuffer* buffer = [p bufferForOutput];
    GtkTextIter iter;
    char szBuff[256];
    size_t reads;
    close(fd[1]);
    while (waitpid(-1, &status, WNOHANG) != pid) {
      while (reads = read(fd[0], szBuff, 256)) {
    gtk_text_buffer_get_end_iter(buffer, &iter);
    gtk_text_buffer_insert(buffer, &iter, szBuff, reads);
    usleep(1);
      }
      usleep(1);
    }

    close(fd[0]);
  }
  gdk_threads_leave();
  return (void*)0;
}