1 files changed, 133 insertions, 0 deletions
diff --git a/app/wlib/gtklib/osxhelp.c b/app/wlib/gtklib/osxhelp.c
new file mode 100644
index 0000000..829ec94
--- /dev/null
+++ b/app/wlib/gtklib/osxhelp.c
@@ -0,0 +1,133 @@
+/** \file osxhelp.c
+ * use OSX Help system
+ */
+
+/*  XTrkCad - Model Railroad CAD
+ *  Copyright (C) 2015 Martin Fischer
+ *
+ *  This program is free software; you can redistribute it and/or modify
+ *  it under the terms of the GNU General Public License as published by
+ *  the Free Software Foundation; either version 2 of the License, or
+ *  (at your option) any later version.
+ *
+ *  This program is distributed in the hope that it will be useful,
+ *  but WITHOUT ANY WARRANTY; without even the implied warranty of
+ *  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ *  GNU General Public License for more details.
+ *
+ *  You should have received a copy of the GNU General Public License
+ *  along with this program; if not, write to the Free Software
+ *  Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA.
+ */
+
+#include <stdio.h>
+#include <stdlib.h>
+#include <sys/stat.h>
+#include <sys/wait.h>
+#include <string.h>
+#include <errno.h>
+#include <fcntl.h>
+
+#include "gtkint.h"
+#include "i18n.h"
+
+#define HELPCOMMANDPIPE "/tmp/helppipe"
+#define EXITCOMMAND "##exit##"
+#define HELPERPROGRAM "helphelper"
+
+static pid_t pidOfChild;
+static int handleOfPipe;
+extern char *wExecutableName;
+
+/**
+ * Create the fully qualified filename for the help helper
+ *
+ * \param parent IN path and filename of parent process
+ * \return filename for the child process
+ */
+
+static
+char *ChildProgramFile(char *parentProgram)
+{
+    char *startOfFilename;
+    char *childProgram;
+
+    childProgram = malloc(strlen(parentProgram)+ sizeof(HELPERPROGRAM) + 1);
+    strcpy(childProgram, parentProgram);
+    startOfFilename = strrchr(childProgram, '/');
+    strcpy(startOfFilename + 1, HELPERPROGRAM);
+
+    return (childProgram);
+}
+
+
+/**
+ * Invoke the help system to display help for <topic>.
+ *
+ * \param topic IN topic string
+ */
+
+void wHelp(const char * topic)
+{
+    pid_t newPid;
+    int len;
+    int status;
+    const char html[] = ".html";
+    char *page;
+    
+    // check whether child already exists
+    if (pidOfChild != 0) {
+        if (waitpid(pidOfChild, &status, WNOHANG) > 0) {
+            // child exited -> clean up
+            close(handleOfPipe);
+            unlink(HELPCOMMANDPIPE);
+            handleOfPipe = 0;
+            pidOfChild = 0;		// child exited
+        }
+    }
+
+    // (re)start child
+    if (pidOfChild == 0) {
+        mkfifo(HELPCOMMANDPIPE, 0666);
+        newPid = fork();  /* New process starts here */
+
+        if (newPid > 0) {
+            pidOfChild = newPid;
+        } else if (newPid == 0) {
+			char *child = ChildProgramFile(wExecutableName);
+            
+            if (execlp(child, child, NULL) < 0) {   /* never normally returns */
+                exit(8);
+            }
+            
+            free(child);
+        } else { /* -1 signifies fork failure */
+            pidOfChild = 0;
+            return;
+        }
+    }
+
+    if (!handleOfPipe) {
+        handleOfPipe = open(HELPCOMMANDPIPE, O_WRONLY);
+
+        if (handleOfPipe < 0) {
+            kill(pidOfChild, SIGKILL);  /* tidy up on next call */
+        }
+
+    }
+
+    page = malloc(strlen(topic) + strlen(html) + 1);
+
+    if (!page) {
+        return;
+    }
+
+    strcpy(page, topic);
+    strcat(page, html);
+    len = strlen(page);
+
+    write(handleOfPipe, &len, sizeof(int));
+    write(handleOfPipe, page, strlen(page)+1);
+
+    free(page);
+}