Re: How to launch Octave with its GUI ?

[John Swensen]

Shai Ayal wrote:
> On 8/2/07, John Swensen <address@hidden> wrote:
>   
> > See my patch from
> > http://www.nabble.com/Proposed-patch-for-threadsafe-access-to-octave-internal-data-tf4080964.html
> > No one ever commented on it, so for the time being I am just going to
> > put it in my program and register for the octave_rl_event_hook()
> > callback to determine when octave is idle at the prompt.
> >     
>
> I have a feeling that the rl_event_hook is going to be heavily used in
> the near future by several in-the-works GUI components. I suggest we
> implement a mechanism which will allow several hooks to be registered
> at once.  I will try to implement this, but it will take me sometime,
> so if anyone can do it faster, please do.
>
> Shai
>
>   
Here is a patch for allowing multiple "users" to register with the 
rl_event_hook.  I basically made a toplevel event_hook function that 
resides in oct-rl-edit.cc and in turn calls all other registered 
event_hook functions in the order they were registered.  I added the 
functions
octave_rl_add_event_hook
octave_rl_remove_event_hook
octave_rl_get_event_hook_list

The part I am not 100% sure about is the changes I made to cmd-edit.cc.  
They work fine for what I am doing, but I am not sure how these are used 
elsewhere.  I simply made the do_set_event_hook() function call the 
octave_rl_add_event_hook() function and the do_restore_event_hook() call 
octave_rl_remove_event_hook() with the most recently added event_hook.  
Probably not the best method, but am open to suggestions from someone 
who has a better understanding of the cmd-edit.cc file and the 
gnu_readline class.

John Swensen

Index: liboctave/cmd-edit.cc
===================================================================
RCS file: /cvs/octave/liboctave/cmd-edit.cc,v
retrieving revision 1.31
diff -u -r1.31 cmd-edit.cc
--- liboctave/cmd-edit.cc       30 Jun 2006 18:19:42 -0000      1.31
+++ liboctave/cmd-edit.cc       2 Aug 2007 04:42:06 -0000
@@ -404,20 +404,21 @@
 gnu_readline::do_restore_startup_hook (void)
 {
   ::octave_rl_set_startup_hook (previous_startup_hook);
+  
 }
 
 void
 gnu_readline::do_set_event_hook (event_hook_fcn f)
 {
-  previous_event_hook = octave_rl_get_event_hook ();
-
-  ::octave_rl_set_event_hook (f);
+  previous_event_hook = f; //octave_rl_get_event_hook ();
+  ::octave_rl_add_event_hook (f);
 }
 
 void
 gnu_readline::do_restore_event_hook (void)
 {
-  ::octave_rl_set_event_hook (previous_event_hook);
+  //::octave_rl_add_event_hook (previous_event_hook);
+  ::octave_rl_remove_event_hook( previous_event_hook );
 }
 
 void
Index: liboctave/oct-rl-edit.c
===================================================================
RCS file: /cvs/octave/liboctave/oct-rl-edit.c,v
retrieving revision 1.20
diff -u -r1.20 oct-rl-edit.c
--- liboctave/oct-rl-edit.c     24 Apr 2006 19:13:08 -0000      1.20
+++ liboctave/oct-rl-edit.c     2 Aug 2007 04:42:07 -0000
@@ -34,6 +34,24 @@
 
 #include "oct-rl-edit.h"
 
+#define MAX_RL_EVENT_HOOK_COUNT 256
+
+/**
+ * Variables containing the number of registered readline event hooks.
+ */
+int rl_event_hook_list_size = 0;
+
+/**
+ * A list of registered readline event hooks.
+ */
+rl_event_hook_fcn_ptr rl_event_hook_list[MAX_RL_EVENT_HOOK_COUNT];
+
+/**
+ * Mutex for providing threadsafe access to the list of readline
+ * event hooks.
+ */
+pthread_mutex_t event_hook_list_mutex = 0;
+
 #define OCTAVE_RL_SAVE_STRING(ss, s) \
   static char *ss = 0; \
  \
@@ -252,7 +270,9 @@
 
 void
 octave_rl_set_event_hook (rl_event_hook_fcn_ptr f)
-{
+{ 
+  pthread_mutex_destroy(&event_hook_list_mutex);
+  pthread_mutex_init(&event_hook_list_mutex, NULL);
   rl_event_hook = f;
 }
 
@@ -262,6 +282,75 @@
   return rl_event_hook;
 }
 
+int
+octave_rl_event_hook( void )
+{
+  pthread_mutex_lock( &event_hook_list_mutex );
+
+  // Iterate through the registered event hook functions in the order they were
+  // received.
+  int i = 0;
+  for( i = 0 ; i < rl_event_hook_list_size ; i++ )
+  {
+    rl_event_hook_list[i]();
+  }
+  
+  pthread_mutex_unlock( &event_hook_list_mutex );
+
+  return 0;
+}
+
+void
+octave_rl_add_event_hook (rl_event_hook_fcn_ptr f)
+{
+  pthread_mutex_lock( &event_hook_list_mutex );
+
+  if( rl_event_hook_list_size > MAX_RL_EVENT_HOOK_COUNT )
+  {
+    printf( "The maximum number of readline event hooks is already in use.\n" 
);
+  }
+  else
+  {
+    rl_event_hook_list[rl_event_hook_list_size++] = f ;
+  }
+
+  pthread_mutex_unlock( &event_hook_list_mutex );
+}
+
+void
+octave_rl_remove_event_hook( rl_event_hook_fcn_ptr f )
+{
+  pthread_mutex_lock( &event_hook_list_mutex );
+
+  // Iterate through the registered event hook functions in the order they were
+  // received, find the matching event_hook, remove it, and shift all the 
remaining
+  // entries up
+  int i = 0;
+  int shiftEntries = 0;
+  for( i = 0 ; i < rl_event_hook_list_size ; i++ )
+  {
+    if( rl_event_hook_list[i] == f )
+    {
+      shiftEntries = 1;
+    }
+
+    if( shiftEntries && i < (rl_event_hook_list_size-1) )
+    {
+      rl_event_hook_list[i] = rl_event_hook_list[i+1];
+    }
+  }
+  if( shiftEntries )
+    rl_event_hook_list_size--;
+
+  pthread_mutex_unlock( &event_hook_list_mutex );
+}
+
+rl_event_hook_fcn_ptr*
+octave_rl_get_event_hook_list (void)
+{
+  return &rl_event_hook_list[0];
+}
+
 char **
 octave_rl_completion_matches (const char *text, rl_completer_fcn_ptr f)
 {
Index: liboctave/oct-rl-edit.h
===================================================================
RCS file: /cvs/octave/liboctave/oct-rl-edit.h,v
retrieving revision 1.7
diff -u -r1.7 oct-rl-edit.h
--- liboctave/oct-rl-edit.h     26 Apr 2005 19:24:29 -0000      1.7
+++ liboctave/oct-rl-edit.h     2 Aug 2007 04:42:07 -0000
@@ -96,6 +96,14 @@
 
 extern rl_event_hook_fcn_ptr octave_rl_get_event_hook (void);
 
+extern int octave_rl_event_hook( void );
+
+extern void octave_rl_add_event_hook( rl_event_hook_fcn_ptr f );
+
+extern void octave_rl_remove_event_hook( rl_event_hook_fcn_ptr f );
+
+extern rl_event_hook_fcn_ptr* octave_rl_get_event_hook_list(void);
+
 extern char **
 octave_rl_completion_matches (const char *, rl_completer_fcn_ptr);
 
Index: src/toplev.cc
===================================================================
RCS file: /cvs/octave/src/toplev.cc,v
retrieving revision 1.200
diff -u -r1.200 toplev.cc
--- src/toplev.cc       31 May 2007 20:23:45 -0000      1.200
+++ src/toplev.cc       2 Aug 2007 04:42:10 -0000
@@ -65,9 +65,10 @@
 #include "parse.h"
 #include "pathsearch.h"
 #include "procstream.h"
+#include "oct-rl-edit.h"
 #include "ov.h"
 #include "pt-jump.h"
 #include "pt-stmt.h"
 #include "sighandlers.h"
 #include "sysdep.h"
 #include "syswait.h"
@@ -203,6 +205,7 @@
   octave_initialized = true;
 
   // The big loop.
+  octave_rl_set_event_hook( &octave_rl_event_hook );
 
   int retval = 0;
   do