[python] another round of fixlets

[Tom Tromey <tromey at redhat dot com>]

I'm checking this in on the python branch.

This fixes a few more oddities pointed out by Vladimir, either in his
note here earlier today, or in the thread on the gdb list.

In particular:

* We are better about computing the "numchild" result
* We emit "{...}" as the value of a varobj that has children
* We emit "has_more" for -var-create; this can be used to discover
  whether the varobj has dynamic children

Vladimir, I made up this last one to allow discoverability of dynamic
children by the MI user.  Maybe it isn't the best way to go ... let me
know what you think, we can certainly do something else here.

Tom

2009-08-19  Tom Tromey  <tromey@redhat.com>

	* mi/mi-cmd-var.c (mi_cmd_var_create): Emit 'has_more' field.
	(mi_cmd_var_list_children): Properly compute 'numchild' field.
	* varobj.c (varobj_get_num_children): Call
	update_dynamic_varobj_children.
	(value_get_print_value): Likewise.  Return "{...}" if varobj has
	children.

2009-08-19  Tom Tromey  <tromey@redhat.com>

	* gdb.mi/mi-var-cmd.exp: Update.
	* gdb.mi/mi-break.exp (test_error): Update.

diff --git a/gdb/mi/mi-cmd-var.c b/gdb/mi/mi-cmd-var.c
index 73c6482..6f488b8 100644
--- a/gdb/mi/mi-cmd-var.c
+++ b/gdb/mi/mi-cmd-var.c
@@ -142,6 +142,8 @@ mi_cmd_var_create (char *command, char **argv, int argc)
 
   print_varobj (var, PRINT_ALL_VALUES, 0 /* don't print expression */);
 
+  ui_out_field_int (uiout, "has_more", varobj_has_more (var, 0));
+
   do_cleanups (old_cleanups);
 }
 
@@ -408,7 +410,7 @@ mi_cmd_var_list_children (char *command, char **argv, int argc)
     }
 
   children = varobj_list_children (var, &from, &to);
-  ui_out_field_int (uiout, "numchild", VEC_length (varobj_p, children));
+  ui_out_field_int (uiout, "numchild", to - from);
   if (argc == 2 || argc == 4)
     print_values = mi_parse_values_option (argv[0]);
   else
diff --git a/gdb/testsuite/gdb.mi/mi-break.exp b/gdb/testsuite/gdb.mi/mi-break.exp
index 619727d..8d06c0e 100644
--- a/gdb/testsuite/gdb.mi/mi-break.exp
+++ b/gdb/testsuite/gdb.mi/mi-break.exp
@@ -175,7 +175,7 @@ proc test_error {} {
     # containing function call, the internal breakpoint created to handle
     # function call would be reported, messing up MI output.
     mi_gdb_test "-var-create V * return_1()" \
-        "\\^done,name=\"V\",numchild=\"0\",value=\"1\",type=\"int\"" \
+        "\\^done,name=\"V\",numchild=\"0\",value=\"1\",type=\"int\",has_more=\"0\"" \
         "create varobj for function call"
 
     mi_gdb_test "-var-update *" \
diff --git a/gdb/testsuite/gdb.mi/mi-var-cmd.exp b/gdb/testsuite/gdb.mi/mi-var-cmd.exp
index ad2e55c..31238c2 100644
--- a/gdb/testsuite/gdb.mi/mi-var-cmd.exp
+++ b/gdb/testsuite/gdb.mi/mi-var-cmd.exp
@@ -377,7 +377,7 @@ mi_gdb_test "-var-update *" \
 	"assign same value to func (update)"
 
 mi_gdb_test "-var-create array_ptr * array_ptr" \
-	"\\^done,name=\"array_ptr\",numchild=\"1\",value=\"$hex\",type=\"int \\*\"" \
+	"\\^done,name=\"array_ptr\",numchild=\"1\",value=\"$hex\",type=\"int \\*\",has_more=\"0\"" \
 	"create global variable array_ptr"
 
 mi_gdb_test "-var-assign array_ptr array2" \
@@ -596,7 +596,7 @@ mi_check_varobj_value F 7 "check F inside callee"
 # A varobj we fail to read during -var-update should be considered
 # out of scope.
 mi_gdb_test "-var-create null_ptr * **0" \
-    {\^done,name="null_ptr",numchild="0",value=".*",type="int"} \
+    {\^done,name="null_ptr",numchild="0",value=".*",type="int",has_more="0"} \
     "create null_ptr"
 
 # Allow this to succeed, if address zero is readable, although it
diff --git a/gdb/varobj.c b/gdb/varobj.c
index f0ad1ac..357c990 100644
--- a/gdb/varobj.c
+++ b/gdb/varobj.c
@@ -1052,23 +1052,21 @@ update_dynamic_varobj_children (struct varobj *var,
 int
 varobj_get_num_children (struct varobj *var)
 {
-  int result = var->num_children;
-
   if (var->num_children == -1)
     {
       if (var->pretty_printer)
 	{
-	  /* If we have a dynamic varobj, don't report -1 children.  */
-	  result = 0;
+	  int dummy;
+
+	  /* If we have a dynamic varobj, don't report -1 children.
+	     So, try to fetch some children first.  */
+	  update_dynamic_varobj_children (var, NULL, NULL, &dummy, 0, 0);
 	}
       else
-	{
-	  var->num_children = number_of_children (var);
-	  result = var->num_children;
-	}
+	var->num_children = number_of_children (var);
     }
 
-  return var->num_children;
+  return var->num_children >= 0 ? var->num_children : 0;
 }
 
 /* Creates a list of the immediate children of a variable object;
@@ -2383,43 +2381,56 @@ value_get_print_value (struct value *value, enum varobj_display_formats format,
     struct cleanup *back_to = varobj_ensure_python_env (var);
     PyObject *value_formatter = var->pretty_printer;
 
-    if (value_formatter && PyObject_HasAttr (value_formatter,
-					     gdbpy_to_string_cst))
+    if (value_formatter)
       {
-	char *hint;
-	struct value *replacement;
-	int string_print = 0;
-	PyObject *output = NULL;
-
-	hint = gdbpy_get_display_hint (value_formatter);
-	if (hint)
+	/* First check to see if we have any children at all.  If so,
+	   we simply return {...}.  */
+	if (var->num_children == -1)
 	  {
-	    if (!strcmp (hint, "string"))
-	      string_print = 1;
-	    xfree (hint);
+	    int dummy;
+	    update_dynamic_varobj_children (var, NULL, NULL, &dummy, 0, 0);
 	  }
+	if (var->num_children > 0 || var->saved_item)
+	  return xstrdup ("{...}");
 
-	output = apply_varobj_pretty_printer (value_formatter,
-					      &replacement);
- 	if (output)
-  	  {
- 	    PyObject *py_str = python_string_to_target_python_string (output);
- 	    if (py_str)
- 	      {
- 		char *s = PyString_AsString (py_str);
- 		len = PyString_Size (py_str);
-		thevalue = xmemdup (s, len + 1, len + 1);
- 		Py_DECREF (py_str);
-	      }
- 	    Py_DECREF (output);
-	  }
-	if (thevalue && !string_print)
+	if (PyObject_HasAttr (value_formatter, gdbpy_to_string_cst))
 	  {
-	    do_cleanups (back_to);
-	    return thevalue;
+	    char *hint;
+	    struct value *replacement;
+	    int string_print = 0;
+	    PyObject *output = NULL;
+
+	    hint = gdbpy_get_display_hint (value_formatter);
+	    if (hint)
+	      {
+		if (!strcmp (hint, "string"))
+		  string_print = 1;
+		xfree (hint);
+	      }
+
+	    output = apply_varobj_pretty_printer (value_formatter,
+						  &replacement);
+	    if (output)
+	      {
+		PyObject *py_str
+		  = python_string_to_target_python_string (output);
+		if (py_str)
+		  {
+		    char *s = PyString_AsString (py_str);
+		    len = PyString_Size (py_str);
+		    thevalue = xmemdup (s, len + 1, len + 1);
+		    Py_DECREF (py_str);
+		  }
+		Py_DECREF (output);
+	      }
+	    if (thevalue && !string_print)
+	      {
+		do_cleanups (back_to);
+		return thevalue;
+	      }
+	    if (replacement)
+	      value = replacement;
 	  }
-	if (replacement)
-	  value = replacement;
       }
     do_cleanups (back_to);
   }