Added lockfile feature, to prevent multiple launches within 30 seconds

(due to over-clicking, for example).

docs/CHANGES.txt

@@ -7,7 +7,15 @@ bill@newbreedsoftware.com
 http://www.newbreedsoftware.com/tuxpaint/
 
 
-2004.September.04 (0.9.14) [cvs]
+2004.September.13 (0.9.14) [cvs]
+  * Added lockfile support, to prevent Tux Paint from being launched more
+    than once every 30 seconds.  (Disable with "--nolockfile" command-line
+    argument.)  Thanks to Darci Lindgren for suggestion the feature, and
+    Mark K. Kim for suggesting it be time-based.
+    
+    (Lockfile is "lockfile.dat" in "~/.tuxpaint/" on Linux/Unix, and
+    "userdata\" on Windows.)
+
   * Updated Catalan translation.
     Pere Pujal Carabantes <ppujal@airtel.net>
 

docs/README.txt

@@ -9,7 +9,7 @@
                           [2]bill@newbreedsoftware.com
                   [3]http://www.newbreedsoftware.com/tuxpaint/
 
-                         June 14, 2002 - June 20, 2004
+                       June 14, 2002 - September 13, 2004
 
    ---------------------------------------------------------------------------
 
@@ -384,6 +384,8 @@ Options
                      |----------------------+--------------------+-----------|
                      |british-english       |british             |           |
                      |----------------------+--------------------+-----------|
+                     |bulgarian             |                    |           |
+                     |----------------------+--------------------+-----------|
                      |catalan               |catala              |           |
                      |----------------------+--------------------+-----------|
                      |chinese               |simplified-chinese  |           |
@@ -553,6 +555,23 @@ Options
                    Only your own configuration file, "~/.tuxpaintrc", if it
                    exists, will be used.
 
+           --nolockfile
+
+                   By default, Tux Paint uses what's known as a 'lockfile' to
+                   prevent it from being launched more than once in
+                   30 seconds. (This is to avoid accidentally running
+                   multiple copies; for example, by double-clicking a
+                   single-click launcher, or simply impatiently clicking the
+                   icon multiple times.)
+
+                   To make Tux Paint ignore the lockfile, allowing it to run
+                   again, even if it was just launched less than 30 seconds
+                   ago, run Tux Paint with the '--nolockfile' option on the
+                   command-line.
+
+                   By default, the lockfile is stored in "~/.tuxpaint/" under
+                   Linux and Unix, and "userdata\" under Windows.
+
    ---------------------------------------------------------------------------
 
   Command-Line Informational Options
@@ -606,6 +625,8 @@ Options
            |---------------+-------------------+---------------------|
            |be_BY          |Bielaruskaja       |Belarusian           |
            |---------------+-------------------+---------------------|
+           |bg_BG          |                   |Bulgarian            |
+           |---------------+-------------------+---------------------|
            |br_FR          |Brezhoneg          |Breton               |
            |---------------+-------------------+---------------------|
            |ca_ES          |Catal`a            |Catalan              |

docs/html/README.html

@@ -23,7 +23,7 @@ New Breed Software</p>
 <p><a href="mailto:bill@newbreedsoftware.com">bill@newbreedsoftware.com</a><br>
 <a href="http://www.newbreedsoftware.com/tuxpaint/">http://www.newbreedsoftware.com/tuxpaint/</a></p>
 
-<p>June 14, 2002 - August 19, 2004</p>
+<p>June 14, 2002 - September 13, 2004</p>
 </center>
 
 <hr size=2 noshade>
@@ -820,6 +820,24 @@ New Breed Software</p>
 	  <p>Only your own configuration file, "<code>~/.tuxpaintrc</code>",
           if it exists, will be used.</p>
 	</dd>
+
+        <dt><code><b>--nolockfile</b></code></dt>
+        <dd>
+	  <p>By default, Tux&nbsp;Paint uses what's known as a 'lockfile'
+	  to prevent it from being launched more than once in 30&nbsp;seconds.
+	  (This is to avoid accidentally running multiple copies; for example,
+	  by double-clicking a single-click launcher, or simply
+	  impatiently clicking the icon multiple times.)</p>
+
+	  <p>To make Tux&nbsp;Paint ignore the lockfile, allowing it to
+	  run again, even if it was just launched less than 30&nbsp;seconds
+	  ago, run Tux&nbsp;Paint with the '<code>--nolockfile</code>' option
+	  on the command-line.</p>
+
+	  <p>By default, the lockfile is stored in
+	  "<code>~/.tuxpaint/</code>" under Linux and Unix,
+	  and "<code>userdata\</code>" under Windows.</p>
+	</dd>
       </dl>
       </blockquote>
     </blockquote>

src/manpage/tuxpaint.1

@@ -1,5 +1,5 @@
-.\" tuxpaint.1 - 2004.08.19
+.\" tuxpaint.1 - 2004.09.13
-.TH TUXPAINT 1 "19 Aug 2004" "0.9.14" "Tux Paint"
+.TH TUXPAINT 1 "13 Sep 2004" "0.9.14" "Tux Paint"
 .SH NAME
 tuxpaint -- A drawing program for young children.
 
@@ -65,7 +65,7 @@ tuxpaint -- A drawing program for young children.
 
 .TP 9
 .B tuxpaint
-[\-\-nosysconfig]
+[\-\-nosysconfig] [\-\-nolockfile]
 
 .SH DESCRIPTION
 .PP
@@ -403,6 +403,14 @@ Display a lists of all supported languages.
 With this option, \fITux Paint\fP will not attempt to read the
 system-wide configuration file (typically \fI/etc/tuxpaint/tuxpaint.conf\fP).
 
+.TP 8
+.B \-\-nolockfile
+By default, \fITux Paint\fP uses a lockfile (stored in the user's
+local Tux Paint directory) which prevents it from being launched more than
+once in 30 seconds. (Sometimes children get too eager, or user interfaces
+only require one click, but users think they need to double-click.)
+This option makes \fITux Paint\fP ignore the current lockfile.
+
 .SH ENVIRONMENT
 .l
 While \fITux Paint\fP may refer to a number of environment variables indirectly
@@ -435,7 +443,8 @@ User's configuration file.  It can be used to set default options
 override any settings in the system-wide configuration file.
 .RS
 .PP
-(Not created or edited automatically; must be created manually.)
+(Not created or edited automatically; must be created manually.
+You can do this by hand, or use '\fITux Paint Config.\fP.')
 .RE
 .TP 8
 .B $HOME/.tuxpaint/saved/
@@ -455,6 +464,16 @@ is re-run.)
 .PP
 (Created when \fITux Paint\fP is \fIQuit\fP.)
 .RE
+.TP 8
+.B $HOME/.tuxpaint/lockfile.dat
+A lockfile that prevents \fITux Paint\fP from being launched more than once
+every 30 seconds.  Disable checking the lockfile by using the
+'\-\-nolockfile' command-line argument.
+.RS
+.PP
+(There's no reason to delete the lockfile, as it contains a timestamp
+inside which causes it to expire after 30 seconds.)
+.RE
 
 .SH COPYRIGHT
 This program is free software; you can redistribute it and/or modify

src/tuxpaint.c

@@ -21,12 +21,12 @@
   along with this program; if not, write to the Free Software
   Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
   
-  June 14, 2002 - September 4, 2004
+  June 14, 2002 - September 13, 2004
 */
 
 
 #define VER_VERSION     "0.9.14"
-#define VER_DATE        "2004-09-04"
+#define VER_DATE        "2004-09-13"
 
 
 /* #define DEBUG */
@@ -3746,7 +3746,7 @@ void show_usage(FILE * f, char * prg)
 #endif
 	  "  %s [--printdelay=SECONDS]\n"
 	  "  %s [--lang LANGUAGE | --locale LOCALE | --lang help]\n"
-	  "  %s [--nosysconfig]\n"
+	  "  %s [--nosysconfig] [--nolockfile]\n"
 	  /* "  %s [--record FILE | --playback FILE]\n" */
 	  "\n",
 	  prg, prg,
@@ -3903,7 +3903,7 @@ const char *getfilename(const char* path)
 
 void setup(int argc, char * argv[])
 {
-  int i, ok_to_use_sysconfig;
+  int i, ok_to_use_sysconfig, ok_to_use_lockfile;
   char str[128];
   char * upstr;
   SDL_Color black = {0, 0, 0, 0};
@@ -3961,6 +3961,7 @@ void setup(int argc, char * argv[])
   playfile = NULL;
   recording = 0;
   playing = 0;
+  ok_to_use_lockfile = 1;
   
 
 #ifdef __BEOS__
@@ -3979,6 +3980,7 @@ void setup(int argc, char * argv[])
 #endif
 
 
+
   /* Load options from global config file: */
 
 #ifndef WIN32
@@ -4370,6 +4372,11 @@ void setup(int argc, char * argv[])
 	{
 	  debug("Not using system config.");   
 	}
+      else if (strcmp(argv[i], "--nolockfile") == 0)
+        {
+	  debug("Not using lockfile");   
+          ok_to_use_lockfile = 0;
+        }
       else
 	{
 	  show_usage(stderr, (char *) getfilename(argv[0]));
@@ -4691,6 +4698,66 @@ void setup(int argc, char * argv[])
 #endif
   
   
+  /* Test for lockfile, if we're using one: */
+
+  if (ok_to_use_lockfile)
+  {
+    char * lock_fname;
+    FILE * fi;
+    time_t time_lock, time_now;
+
+
+    /* Get the current time: */
+    
+    time_now = time(NULL);
+    
+
+    /* Look for the lockfile... */
+
+    lock_fname = get_fname("lockfile.dat");
+
+    fi = fopen(lock_fname, "r");
+    if (fi != NULL)
+    {
+      /* If it exists, read its contents: */
+
+      if (fread(&time_lock, sizeof(time_t), 1, fi) > 0)
+      {
+	/* Has it not been 30 seconds yet? */
+
+	if (time_now < time_lock + 30)
+	{
+          /* FIXME: Wrap in gettext() */
+          printf("\nYou're already running a copy of Tux Paint!\n\n");
+
+	  fclose(fi);
+          exit(0);
+	}
+      }
+
+      fclose(fi);
+    }
+
+
+    /* Okay to run; create/update the lockfile */
+
+    fi = fopen(lock_fname, "w");
+    if (fi != NULL)
+    {
+      /* If we can write to it, do so! */
+
+      fwrite(&time_now, sizeof(time_t), 1, fi);
+      fclose(fi);
+    }
+    else
+    {
+      fprintf(stderr,
+ 	      "\nWarning: I couldn't create the lockfile (%s)\n"
+	      "The error that occurred was:\n"
+	      "%s\n\n", lock_fname, strerror(errno));
+    }
+  }
+
 
   /* Init SDL Video: */