[python] change varobj child listing

[Tom Tromey <tromey at redhat dot com>]

This implements the -var-list-children changes requested by Volodya,
to the best of my understanding.

Basically, -var-set-child-range is gone, and now -var-list-children
takes an optional child range.  Also, -var-list-children and
-var-update will emit a `has_more' attribute if the varobj has more
children after the final selected child.

Tom

b/gdb/ChangeLog:
2009-07-10  Tom Tromey  <tromey@redhat.com>

	* varobj.c (update_dynamic_varobj_children): Fetch one extra
	child.
	* mi/mi-cmds.h (mi_cmd_var_set_child_range): Remove.
	* mi/mi-cmds.c (mi_cmds): Remove var-set-child-range.
	* mi/mi-cmd-var.c (mi_cmd_var_set_child_range): Remove.
	(mi_cmd_var_list_children): Accept 'from' and 'to' arguments.
	Emit 'has_more' attribute.
	(varobj_update_one): Emit 'has_more' attribute.

b/gdb/doc/ChangeLog:
2009-07-10  Tom Tromey  <tromey@redhat.com>

	* gdb.texinfo (GDB/MI Variable Objects) <-var-list-children>:
	Mention from and to arguments, has_more attribute.
	<-var-set-child-range>: Remove.

b/gdb/testsuite/ChangeLog:
2009-07-10  Tom Tromey  <tromey@redhat.com>

	* gdb.mi/mi-var-display.exp: Update.
	* gdb.mi/mi2-var-display.exp: Update.
	* gdb.mi/gdb701.exp: Update.
	* lib/mi-support.exp (mi_varobj_update_dynamic): Handle
	"has_more".
	(mi_list_varobj_children): Update.
	(mi_list_varobj_children_range): Add 'from' and 'to' parameters.
	* gdb.python/python-mi.exp: Update for changes to
	-var-list-children.

diff --git a/gdb/doc/gdb.texinfo b/gdb/doc/gdb.texinfo
index 7ac503f..b93bd75 100644
--- a/gdb/doc/gdb.texinfo
+++ b/gdb/doc/gdb.texinfo
@@ -23754,7 +23754,7 @@ Returns the number of children of a variable object @var{name}:
 @subsubheading Synopsis
 
 @smallexample
- -var-list-children [@var{print-values}] @var{name}
+ -var-list-children [@var{print-values}] @var{name} [@var{from} @var{to}]
 @end smallexample
 @anchor{-var-list-children} 
 
@@ -23767,6 +23767,18 @@ values; and if it is 2 or @code{--simple-values} print the name and
 value for simple data types and just the name for arrays, structures
 and unions.
 
+@var{from} and @var{to}, if specified, indicate the range of children
+to report.  If @var{from} or @var{to} is less than zero, the range is
+reset and all children will be reported.  Otherwise, children starting
+at @var{from} (zero-based) and ending just before @var{to} will be
+reported.  The selected range is sticky; future calls to
+@code{-var-update} or @code{-var-list-children} will use any
+previously set range.
+
+The result may include a @code{has_more} attribute.  This is an
+integer attribute which is nonzero if there are children remaining
+after the end of the selected range.
+
 @subsubheading Example
 
 @smallexample
@@ -24074,46 +24086,6 @@ can be used to instantiate this class for a varobj:
 ^done
 @end smallexample
 
-@subheading The @code{-var-set-child-range} command
-@findex -var-set-child-range
-@anchor{-var-set-child-range}
-
-@subsubheading Synopsis
-
-@smallexample
- -var-set-child-range @var{name} @var{from} @var{to}
-@end smallexample
-
-Select a sub-range of the children of the variable object @var{name};
-future calls to @code{-var-list-children} will only report the
-selected range of children.  This allows an MI consumer to avoid
-inefficiencies if the varobj has very many children.
-
-If either @var{from} or @var{to} is less than zero, then sub-range
-selection is disabled, and @code{-var-list-children} will report all
-children.
-
-Otherwise, @var{from} and @var{to} are indexes into the array of
-children.  Children starting at @var{from} and stopping jsut before
-@var{to} will be reported.
-
-@subsubheading Example
-
-@smallexample
-(gdb)
- -var-list-children n
- ^done,numchild=3,children=[@{name="a",numchild=0,type="int"@},
- @{name="b",numchild=0,type="int"@},
- @{name="c",numchild=0,type="int"@}]
-(gdb)
- -var-set-child-range n 1 2
-(gdb)
- -var-list-children n
- ^done,numchild=3,children=[@{name="b",numchild=0,type="int"@},
- @{name="c",numchild=0,type="int"@}]
-@end smallexample
-
-
 @c %%%%%%%%%%%%%%%%%%%%%%%%%%%% SECTION %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
 @node GDB/MI Data Manipulation
 @section @sc{gdb/mi} Data Manipulation
diff --git a/gdb/mi/mi-cmd-var.c b/gdb/mi/mi-cmd-var.c
index cb081c0..61e7ee5 100644
--- a/gdb/mi/mi-cmd-var.c
+++ b/gdb/mi/mi-cmd-var.c
@@ -259,25 +259,6 @@ mi_cmd_var_set_visualizer (char *command, char **argv, int argc)
 }
 
 void
-mi_cmd_var_set_child_range (char *command, char **argv, int argc)
-{
-  struct varobj *var;
-  int from, to;
-
-  if (argc != 3)
-    error (_("-var-set-child-range: NAME FROM TO"));
-
-  var = varobj_get_handle (argv[0]);
-  if (var == NULL)
-    error (_("Variable object not found"));
-
-  from = atoi (argv[1]);
-  to = atoi (argv[2]);
-
-  varobj_set_child_range (var, from, to);
-}
-
-void
 mi_cmd_var_set_frozen (char *command, char **argv, int argc)
 {
   struct varobj *var;
@@ -388,32 +369,38 @@ mi_cmd_var_list_children (char *command, char **argv, int argc)
   struct varobj *var;  
   VEC(varobj_p) *children;
   struct varobj *child;
-  struct cleanup *cleanup_children;
   int numchild;
   enum print_values print_values;
   int ix;
   int from, to;
   char *display_hint;
 
-  if (argc != 1 && argc != 2)
-    error (_("mi_cmd_var_list_children: Usage: [PRINT_VALUES] NAME"));
+  if (argc < 1 || argc > 4)
+    error (_("mi_cmd_var_list_children: Usage: [PRINT_VALUES] NAME [FROM TO]"));
 
   /* Get varobj handle, if a valid var obj name was specified */
-  if (argc == 1)
+  if (argc == 1 || argc == 3)
     var = varobj_get_handle (argv[0]);
   else
     var = varobj_get_handle (argv[1]);
 
+  if (argc > 2)
+    {
+      from = atoi (argv[argc - 2]);
+      to = atoi (argv[argc - 1]);
+      varobj_set_child_range (var, from, to);
+    }
+
   children = varobj_list_children (var);
   ui_out_field_int (uiout, "numchild", VEC_length (varobj_p, children));
-  if (argc == 2)
+  if (argc == 2 || argc == 4)
     print_values = mi_parse_values_option (argv[0]);
   else
     print_values = PRINT_NO_VALUES;
 
+  /* Re-fetch the child range, because varobj_get_child_range computes
+     the real start and end indices for us.  */
   varobj_get_child_range (var, children, &from, &to);
-  if (from >= to)
-    return;
 
   display_hint = varobj_get_display_hint (var);
   if (display_hint)
@@ -422,18 +409,29 @@ mi_cmd_var_list_children (char *command, char **argv, int argc)
       xfree (display_hint);
     }
 
-  if (mi_version (uiout) == 1)
-    cleanup_children = make_cleanup_ui_out_tuple_begin_end (uiout, "children");
-  else
-    cleanup_children = make_cleanup_ui_out_list_begin_end (uiout, "children");
-  for (ix = from; ix < to && VEC_iterate (varobj_p, children, ix, child); ++ix)
+  if (from < to)
     {
-      struct cleanup *cleanup_child;
-      cleanup_child = make_cleanup_ui_out_tuple_begin_end (uiout, "child");
-      print_varobj (child, print_values, 1 /* print expression */);
-      do_cleanups (cleanup_child);
+      struct cleanup *cleanup_children;
+      if (mi_version (uiout) == 1)
+	cleanup_children
+	  = make_cleanup_ui_out_tuple_begin_end (uiout, "children");
+      else
+	cleanup_children
+	  = make_cleanup_ui_out_list_begin_end (uiout, "children");
+      for (ix = from;
+	   ix < to && VEC_iterate (varobj_p, children, ix, child);
+	   ++ix)
+	{
+	  struct cleanup *cleanup_child;
+	  cleanup_child = make_cleanup_ui_out_tuple_begin_end (uiout, "child");
+	  print_varobj (child, print_values, 1 /* print expression */);
+	  do_cleanups (cleanup_child);
+	}
+      do_cleanups (cleanup_children);
     }
-  do_cleanups (cleanup_children);
+
+  ui_out_field_int (uiout, "has_more",
+		    VEC_length (varobj_p, children) > to);
 }
 
 void
@@ -743,6 +741,9 @@ varobj_update_one (struct varobj *var, enum print_values print_values,
 	    }
 
 	  do_cleanups (cleanup);
+
+	  ui_out_field_int (uiout, "has_more",
+			    VEC_length (varobj_p, children) > to);
 	}
   
       if (mi_version (uiout) > 1)
diff --git a/gdb/mi/mi-cmds.c b/gdb/mi/mi-cmds.c
index 79ff3ad..4911146 100644
--- a/gdb/mi/mi-cmds.c
+++ b/gdb/mi/mi-cmds.c
@@ -109,7 +109,6 @@ struct mi_cmd mi_cmds[] =
   { "var-info-num-children", { NULL, 0 }, mi_cmd_var_info_num_children},
   { "var-info-type", { NULL, 0 }, mi_cmd_var_info_type},
   { "var-list-children", { NULL, 0 }, mi_cmd_var_list_children},
-  { "var-set-child-range", { NULL, 0 }, mi_cmd_var_set_child_range },
   { "var-set-format", { NULL, 0 }, mi_cmd_var_set_format},
   { "var-set-frozen", { NULL, 0 }, mi_cmd_var_set_frozen},
   { "var-set-visualizer", { NULL, 0 }, mi_cmd_var_set_visualizer},
diff --git a/gdb/mi/mi-cmds.h b/gdb/mi/mi-cmds.h
index 84f6d85..afcba1e 100644
--- a/gdb/mi/mi-cmds.h
+++ b/gdb/mi/mi-cmds.h
@@ -93,7 +93,6 @@ extern mi_cmd_argv_ftype mi_cmd_var_info_num_children;
 extern mi_cmd_argv_ftype mi_cmd_var_info_type;
 extern mi_cmd_argv_ftype mi_cmd_var_list_children;
 extern mi_cmd_argv_ftype mi_cmd_var_set_format;
-extern mi_cmd_argv_ftype mi_cmd_var_set_child_range;
 extern mi_cmd_argv_ftype mi_cmd_var_set_frozen;
 extern mi_cmd_argv_ftype mi_cmd_var_set_visualizer;
 extern mi_cmd_argv_ftype mi_cmd_var_show_attributes;
diff --git a/gdb/testsuite/gdb.mi/gdb701.exp b/gdb/testsuite/gdb.mi/gdb701.exp
index d4acdc2..244c731 100644
--- a/gdb/testsuite/gdb.mi/gdb701.exp
+++ b/gdb/testsuite/gdb.mi/gdb701.exp
@@ -54,7 +54,7 @@ mi_gdb_test "-var-list-children fooPtr" \
 
 foreach i [list x y z] {
   mi_gdb_test "-var-list-children fooPtr.$i" \
-    "(&\".*\"\r\n)*\\^done,numchild=\"0\"" \
+    "(&\".*\"\r\n)*\\^done,numchild=\"0\",has_more=\"0\"" \
     "list children of fooPtr.$i"
 }
 
diff --git a/gdb/testsuite/gdb.mi/mi-var-display.exp b/gdb/testsuite/gdb.mi/mi-var-display.exp
index 59be6b2..584967c 100644
--- a/gdb/testsuite/gdb.mi/mi-var-display.exp
+++ b/gdb/testsuite/gdb.mi/mi-var-display.exp
@@ -558,7 +558,7 @@ mi_gdb_test "-var-info-num-children e" \
 # Test: c_variable-7.55
 # Desc: children of e
 mi_gdb_test "-var-list-children e" \
-	"\\^done,numchild=\"0\"" \
+	"\\^done,numchild=\"0\",has_more=\"0\"" \
 	"get children of e"
 
 # Test: c_variable-7.60
@@ -600,7 +600,7 @@ mi_gdb_test "-var-info-num-children anone" \
 # Test: c_variable-7.75
 # Desc: children of anone
 mi_gdb_test "-var-list-children anone" \
-	"\\^done,numchild=\"0\"" \
+	"\\^done,numchild=\"0\",has_more=\"0\"" \
 	"get children of anone"
 
 
diff --git a/gdb/testsuite/gdb.mi/mi2-var-display.exp b/gdb/testsuite/gdb.mi/mi2-var-display.exp
index 9c98694..7b2ed98 100644
--- a/gdb/testsuite/gdb.mi/mi2-var-display.exp
+++ b/gdb/testsuite/gdb.mi/mi2-var-display.exp
@@ -557,7 +557,7 @@ mi_gdb_test "-var-info-num-children e" \
 # Test: c_variable-7.55
 # Desc: children of e
 mi_gdb_test "-var-list-children e" \
-	"\\^done,numchild=\"0\"" \
+	"\\^done,numchild=\"0\",has_more=\"0\"" \
 	"get children of e"
 
 # Test: c_variable-7.60
@@ -599,7 +599,7 @@ mi_gdb_test "-var-info-num-children anone" \
 # Test: c_variable-7.75
 # Desc: children of anone
 mi_gdb_test "-var-list-children anone" \
-	"\\^done,numchild=\"0\"" \
+	"\\^done,numchild=\"0\",has_more=\"0\"" \
 	"get children of anone"
 
 
diff --git a/gdb/testsuite/gdb.python/python-mi.exp b/gdb/testsuite/gdb.python/python-mi.exp
index 8c6167c..8153f84 100644
--- a/gdb/testsuite/gdb.python/python-mi.exp
+++ b/gdb/testsuite/gdb.python/python-mi.exp
@@ -92,27 +92,11 @@ mi_varobj_update_dynamic container {
     { {container.\[1\]} {\[1\]} 0 int }
 } "varobj update after choosing via expression"
 
-mi_gdb_test "-var-set-child-range container 1 2" \
-  "\\^done" \
-  "select child range"
-
-mi_gdb_test "-var-update container" \
-  "\\^done,changelist=\\\[\\\]" \
-  "varobj update after selecting child range"
-
-mi_list_varobj_children_range container 2 {
+mi_list_varobj_children_range container 1 2 2 {
     { {container.\[1\]} {\[1\]} 0 int }
 } "list varobj children after selecting child range"
 
-mi_gdb_test "-var-set-child-range container -1 -1" \
-  "\\^done" \
-  "reset child range"
-
-mi_gdb_test "-var-update container" \
-  "\\^done,changelist=\\\[\\\]" \
-  "varobj update after resetting child range"
-
-mi_list_varobj_children container {
+mi_list_varobj_children_range container -1 -1 2 {
     { {container.\[0\]} {\[0\]} 0 int }
     { {container.\[1\]} {\[1\]} 0 int }
 } "list varobj children after resetting child range"
diff --git a/gdb/testsuite/lib/mi-support.exp b/gdb/testsuite/lib/mi-support.exp
index 9b4c464..33f277a 100644
--- a/gdb/testsuite/lib/mi-support.exp
+++ b/gdb/testsuite/lib/mi-support.exp
@@ -1258,7 +1258,7 @@ proc mi_varobj_update_dynamic {name children testname} {
     set er "\\^done,changelist=\\\["
 
     append er "{name=\"$name\",in_scope=\"true\",type_changed=\"false\""
-    append er ",children=\\\[$children_exp_j.*\\\]}\\\]"
+    append er ",children=\\\[$children_exp_j.*\\\],has_more=\".\"}\\\]"
 
     verbose -log "Expecting: $er"
     mi_gdb_test "-var-update $name" $er $testname
@@ -1328,14 +1328,13 @@ proc mi_child_regexp {children add_child} {
 # have no value.
 #
 proc mi_list_varobj_children { varname children testname } {
-    mi_list_varobj_children_range $varname [llength $children] $children \
+    mi_list_varobj_children_range $varname "" "" [llength $children] $children \
       $testname
 }
 
-# Like mi_list_varobj_children, but assumes that a subrange has been
-# selected with -var-set-child-range.  NUMCHILDREN is the total number
-# of children.
-proc mi_list_varobj_children_range {varname numchildren children testname} {
+# Like mi_list_varobj_children, but sets a subrange.  NUMCHILDREN is
+# the total number of children.
+proc mi_list_varobj_children_range {varname from to numchildren children testname} {
     set options ""
     if {[llength $varname] == 2} {
         set options [lindex $varname 1]
@@ -1351,9 +1350,18 @@ proc mi_list_varobj_children_range {varname numchildren children testname} {
         set expected "\\^done,numchild=\"0\""
     }
 
+    if {"$to" == ""} {
+        append expected ",has_more=\"0\""
+    } elseif {$to >= 0 && $numchildren > $to} {
+        append expected ",has_more=\"1\""
+    } else {
+        append expected ",has_more=\"0\""
+    }
+
     verbose -log "Expecting: $expected"
 
-    mi_gdb_test "-var-list-children $options $varname" $expected $testname
+    mi_gdb_test "-var-list-children $options $varname $from $to" \
+      $expected $testname
 }
 
 # Verifies that variable object VARNAME has NUMBER children,
diff --git a/gdb/varobj.c b/gdb/varobj.c
index 1412d43..a774cdf 100644
--- a/gdb/varobj.c
+++ b/gdb/varobj.c
@@ -879,7 +879,9 @@ update_dynamic_varobj_children (struct varobj *var,
     }
   make_cleanup_py_decref (iterator);
 
-  for (i = 0; var->to < 0 || i < var->to; ++i)
+  /* We ask for one extra child, so that MI can report whether there
+     are more children.  */
+  for (i = 0; var->to < 0 || i < var->to + 1; ++i)
     {
       PyObject *item = PyIter_Next (iterator);
       PyObject *py_v;