dbstop: conditional breakpoint, dbstop if caught error etc. (bug #46795) * debug.cc (parse_dbfunction_params): Accept "in", "at" and "if" tokens. Only breakpoints are returned; "dbstop if error" etc. are processed in the parser. * debug.cc (dbstop_process_map_ags, Fdbstop): set breakpoints etc. based on the output of A=dbstatus. The structure of A is not Matlab compatible. * debug.cc (do_add_breakpoint_1, do_get_breakpoint_list): Store file (not subfunction) names in bp_set, to avoid crash in "dbclear all". * debug.cc (dbclear_all_signals, condition_valid, stop_on_err_warn_status): New function * debug.cc (do_add_breakpoint): take "condition" parameter. * debug.cc (do_get_breakpoint_list): Make invariant copy of bp_set (bug #44195) * debug.cc (do_add_breakpoint, do_remove_breakpoint, do_remove_all_breakpoints_in_file): More informative error messages. * debug.cc (Fdbclear): clear break on signals (error, warning etc.) * debug.cc (Fdbstatus): Return all breakpoints when debugging, so that "s = dbstatus; ...; dbstop (s)" works. (Related to bug #41338, bug #41556) * debug.cc (Fdbstatus): Return structure with conditions, and "if error" etc. * debug.h (debug_on_err, debug_on_caught, debug_on_warn): New functions * debug.h: Rename "fname_line_map" to "fname_bp_map", as it has conditions * error.cc (verror): Allow dbstop on selected errors, or errors in try/catch * error.h New globals: Vdebug_on_caught, in_try_catch. * toplev.cc: Experimental code for Matlab's "dbstop if naninf". * symtab.cc (load_class_constructor): Add class constructors to list of methods so they can be breakpointed * pt-pb.{cc,h} (take_action): Add "condition" to set_breakpoint call, track bp_cond_list. * pt-eval.cc visit_.*_command: Ask if breakpoint condition is satisfied. * pt-eval.cc (visit_try_catch_command): Count the number of levels of try/catch we are in to allow "dbstop if caught error". * pt-stmt.cc (set_breakpoint): Pass condition * pt-stmt.cc (is_breakpoint): If new argument is true, only return true if the condition is set. * pt-stmt.cc (bp_cond, preakpoints_and_conds): new function * pt-stmt.h: new declarations * pt.{cc,h} (meets_bp_condition, bp_cond): New function * octave-link.h (update_breakpoint): Accept condition

--- a/libinterp/parse-tree/pt.cc	Sat Jan 30 08:22:36 2016 -0800
+++ b/libinterp/parse-tree/pt.cc	Sun Jan 24 11:02:30 2016 +1100
@@ -31,6 +31,7 @@
 #include "ov-fcn.h"
 #include "pt.h"
 #include "pt-pr-code.h"
+#include "unwind-prot.h"
 
 // Hide the details of the string buffer so that we are less likely to
 // create a memory leak.
@@ -48,3 +49,51 @@
 
   return retval;
 }
+
+// function from libinterp/parse-tree/oct-parse.cc, not listed in oct-parse.h
+octave_value_list eval_string (const std::string&, bool, int&, int);
+// Is the current breakpoint condition met?
+bool
+tree::meets_bp_condition () const
+{
+  bool retval;
+  if (bp == 0)
+    retval = false;
+  else if (bp->length () == 0)     // empty condition always met
+    retval = true;
+  else
+    {
+      int parse_status = 0;
+
+      unwind_protect frame;
+      frame.protect_var (buffer_error_messages);
+      frame.protect_var (Vdebug_on_error);
+      frame.protect_var (Vdebug_on_warning);
+
+      buffer_error_messages++;
+      Vdebug_on_error = false;
+      Vdebug_on_warning = false;
+
+      retval = true;                // default to stopping if any error
+      try
+        {
+          octave_value_list val = eval_string (*bp, 1, parse_status, 1);
+          if (parse_status == 0)
+            {
+              if (! val(0).is_scalar_type ())
+                warning ("Breakpoint condition must be a scalar, not size %s",
+                  val(0).dims ().str ('x').c_str ());
+              else
+                retval = val(0).bool_value ();
+            }
+          else
+            warning ("Error parsing breakpoint condition");
+        }
+      catch (const octave_execution_exception& e)
+        {
+          warning ("Error evaluating breakpoint condition:\n    %s",
+                   last_error_message ().c_str ());
+        }
+    }
+  return retval;
+}