[PATCH v3 05/15] extension language API for GDB: breakpoint changes

[Doug Evans <xdje42 at gmail dot com>]

This patch updates breakpoint.c to call the API functions in extension.h.
It also updates py-breakpoint.c, the functions that implement the
extension_language_ops "methods" are all named ${lang}_${method_name}.

The script condition test function, gdbpy_breakpoint_cond_says_stop,
has an enum result instead of just a boolean so that the caller can
know if there is a condition.  One could call the
get_breakpoint_cond_ext_lang "method" except that python "finish
breakpoints" are implemented on top of normal breakpoints and require
calling "breakpoint_cond_says_stop" even if there is no stop method.
I can imagine reworking this, but there's no need to at the moment.

Changes from v2:
- in breakpoint.c, replace #include "python/python.h" with "extension.h"
- in breakpoint.c:condition_command, print name of extension language with
  existing stop condition
- in py-breakpoint.c:local_setattro, print name of extension language with
  existing stop condition
- updated py-breakpoint.exp

Changes from v1:
- updates for scripting -> extension renaming

2013-12-24 Doug Evans  <xdje42@gmail.com>

	* breakpoint.c (condition_command): Replace call to
	gdbpy_breakpoint_has_py_cond with call to get_breakpoint_cond_ext_lang.
	(bpstat_check_breakpoint_conditions): Replace call to gdbpy_should_stop
	with call to breakpoint_ext_lang_cond_says_stop.
	* python/py-breakpoint.c (gdbpy_breakpoint_cond_says_stop): Renamed
	from gdbpy_should_stop.  Change result type to enum scr_bp_stop.
	New arg slang.  Return SCR_BP_STOP_UNSET if py_bp_object is NULL.
	(gdbpy_breakpoint_has_cond): Renamed from gdbpy_breakpoint_has_py_cond.
	New arg slang.
	(local_setattro): Print name of extension language with existing
	stop condition.

	testsuite/
	* gdb.python/py-breakpoint.exp (test_bkpt_eval_funcs): Update expected
	output.

diff --git a/gdb/breakpoint.c b/gdb/breakpoint.c
index 6a11ddf..8013189 100644
--- a/gdb/breakpoint.c
+++ b/gdb/breakpoint.c
@@ -80,7 +80,7 @@
 #undef savestring
 
 #include "mi/mi-common.h"
-#include "python/python.h"
+#include "extension.h"
 
 /* Enums for exception-handling support.  */
 enum exception_event_kind
@@ -1048,14 +1048,18 @@ condition_command (char *arg, int from_tty)
   ALL_BREAKPOINTS (b)
     if (b->number == bnum)
       {
-	/* Check if this breakpoint has a Python object assigned to
-	   it, and if it has a definition of the "stop"
-	   method.  This method and conditions entered into GDB from
-	   the CLI are mutually exclusive.  */
-	if (b->py_bp_object
-	    && gdbpy_breakpoint_has_py_cond (b->py_bp_object))
-	  error (_("Cannot set a condition where a Python 'stop' "
-		   "method has been defined in the breakpoint."));
+	/* Check if this breakpoint has a "stop" method implemented in an
+	   extension language.  This method and conditions entered into GDB
+	   from the CLI are mutually exclusive.  */
+	const struct extension_language_defn *extlang
+	  = get_breakpoint_cond_ext_lang (b, EXT_LANG_NONE);
+
+	if (extlang != NULL)
+	  {
+	    error (_("Only one stop condition allowed.  There is currently"
+		     " a %s stop condition defined for this breakpoint."),
+		   ext_lang_capitalized_name (extlang));
+	  }
 	set_breakpoint_condition (b, p, from_tty);
 
 	if (is_breakpoint (b))
@@ -5140,9 +5144,9 @@ bpstat_check_breakpoint_conditions (bpstat bs, ptid_t ptid)
       return;
     }
 
-  /* Evaluate Python breakpoints that have a "stop" method implemented.  */
-  if (b->py_bp_object)
-    bs->stop = gdbpy_should_stop (b->py_bp_object);
+  /* Evaluate extension language breakpoints that have a "stop" method
+     implemented.  */
+  bs->stop = breakpoint_ext_lang_cond_says_stop (b);
 
   if (is_watchpoint (b))
     {
diff --git a/gdb/python/py-breakpoint.c b/gdb/python/py-breakpoint.c
index 1085588..1d11e84 100644
--- a/gdb/python/py-breakpoint.c
+++ b/gdb/python/py-breakpoint.c
@@ -750,15 +750,22 @@ gdbpy_breakpoints (PyObject *self, PyObject *args)
    stopped at the breakpoint.  Otherwise the inferior will be
    allowed to continue.  */
 
-int
-gdbpy_should_stop (struct gdbpy_breakpoint_object *bp_obj)
+enum ext_lang_bp_stop
+gdbpy_breakpoint_cond_says_stop (const struct extension_language_defn *extlang,
+				 struct breakpoint *b)
 {
-  int stop = 1;
-
+  int stop;
+  struct gdbpy_breakpoint_object *bp_obj = b->py_bp_object;
   PyObject *py_bp = (PyObject *) bp_obj;
-  struct breakpoint *b = bp_obj->bp;
-  struct gdbarch *garch = b->gdbarch ? b->gdbarch : get_current_arch ();
-  struct cleanup *cleanup = ensure_python_env (garch, current_language);
+  struct gdbarch *garch;
+  struct cleanup *cleanup;
+
+  if (bp_obj == NULL)
+    return EXT_LANG_BP_STOP_UNSET;
+
+  stop = -1;
+  garch = b->gdbarch ? b->gdbarch : get_current_arch ();
+  cleanup = ensure_python_env (garch, current_language);
 
   if (bp_obj->is_finish_bp)
     bpfinishpy_pre_stop_hook (bp_obj);
@@ -767,6 +774,7 @@ gdbpy_should_stop (struct gdbpy_breakpoint_object *bp_obj)
     {
       PyObject *result = PyObject_CallMethod (py_bp, stop_func, NULL);
 
+      stop = 1;
       if (result)
 	{
 	  int evaluate = PyObject_IsTrue (result);
@@ -790,7 +798,9 @@ gdbpy_should_stop (struct gdbpy_breakpoint_object *bp_obj)
 
   do_cleanups (cleanup);
 
-  return stop;
+  if (stop < 0)
+    return EXT_LANG_BP_STOP_UNSET;
+  return stop ? EXT_LANG_BP_STOP_YES : EXT_LANG_BP_STOP_NO;
 }
 
 /* Checks if the  "stop" method exists in this breakpoint.
@@ -798,17 +808,21 @@ gdbpy_should_stop (struct gdbpy_breakpoint_object *bp_obj)
    conditions.  */
 
 int
-gdbpy_breakpoint_has_py_cond (struct gdbpy_breakpoint_object *bp_obj)
+gdbpy_breakpoint_has_cond (const struct extension_language_defn *extlang,
+			   struct breakpoint *b)
 {
-  int has_func = 0;
-  PyObject *py_bp = (PyObject *) bp_obj;
-  struct gdbarch *garch = bp_obj->bp->gdbarch ? bp_obj->bp->gdbarch :
-    get_current_arch ();
-  struct cleanup *cleanup = ensure_python_env (garch, current_language);
-
-  if (py_bp != NULL)
-    has_func = PyObject_HasAttrString (py_bp, stop_func);
-
+  int has_func;
+  PyObject *py_bp;
+  struct gdbarch *garch;
+  struct cleanup *cleanup;
+
+  if (b->py_bp_object == NULL)
+    return 0;
+
+  py_bp = (PyObject *) b->py_bp_object;
+  garch = b->gdbarch ? b->gdbarch : get_current_arch ();
+  cleanup = ensure_python_env (garch, current_language);
+  has_func = PyObject_HasAttrString (py_bp, stop_func);
   do_cleanups (cleanup);
 
   return has_func;
@@ -947,16 +961,30 @@ local_setattro (PyObject *self, PyObject *name, PyObject *v)
     return -1;
 
   /* If the attribute trying to be set is the "stop" method,
-     but we already have a condition set in the CLI, disallow this
-     operation.  */
-  if (strcmp (attr, stop_func) == 0 && obj->bp->cond_string)
+     but we already have a condition set in the CLI or other extension
+     language, disallow this operation.  */
+  if (strcmp (attr, stop_func) == 0)
     {
-      xfree (attr);
-      PyErr_SetString (PyExc_RuntimeError,
-		       _("Cannot set 'stop' method.  There is an " \
-			 "existing GDB condition attached to the " \
-			 "breakpoint."));
-      return -1;
+      const struct extension_language_defn *extlang = NULL;
+
+      if (obj->bp->cond_string != NULL)
+	extlang = get_ext_lang_defn (EXT_LANG_GDB);
+      if (extlang == NULL)
+	extlang = get_breakpoint_cond_ext_lang (obj->bp, EXT_LANG_PYTHON);
+      if (extlang != NULL)
+	{
+	  char *error_text;
+
+	  xfree (attr);
+	  error_text
+	    = xstrprintf (_("Only one stop condition allowed.  There is"
+			    " currently a %s stop condition defined for"
+			    " this breakpoint."),
+			  ext_lang_capitalized_name (extlang));
+	  PyErr_SetString (PyExc_RuntimeError, error_text);
+	  xfree (error_text);
+	  return -1;
+	}
     }
 
   xfree (attr);
diff --git a/gdb/testsuite/gdb.python/py-breakpoint.exp b/gdb/testsuite/gdb.python/py-breakpoint.exp
index 107b026..c86695e 100644
--- a/gdb/testsuite/gdb.python/py-breakpoint.exp
+++ b/gdb/testsuite/gdb.python/py-breakpoint.exp
@@ -372,7 +372,7 @@ proc test_bkpt_eval_funcs { } {
 	    "Set breakpoint" 0
 	set test_cond {cond $bpnum}
 	gdb_test "$test_cond \"foo==3\"" \
-	    "Cannot set a condition where a Python.*" \
+	    "Only one stop condition allowed.  There is currently a Python.*" \
 	    "Check you cannot add a CLI condition to a Python breakpoint that has defined stop"
 	gdb_py_test_silent_cmd "python eval_bp2 = basic(\"$cond_bp\")" \
 	    "Set breakpoint" 0
@@ -385,7 +385,7 @@ proc test_bkpt_eval_funcs { } {
 	    "end" ""
 
 	gdb_test "python eval_bp2.stop = stop_func"  \
-	    "RuntimeError: Cannot set 'stop' method.*" \
+	    "RuntimeError: Only one stop condition allowed.  There is currently a GDB.*" \
 	    "Assign stop function to a breakpoint that has a condition"
 
 	delete_breakpoints