[RFA v2 8/8] Let gdb.execute handle multi-line commands

[Tom Tromey <tom at tromey dot com>]

This changes the Python API so that gdb.execute can now handle
multi-line commands, like "commands" or "define".

gdb/ChangeLog
2018-04-25  Tom Tromey  <tom@tromey.com>

	PR python/22730:
	* NEWS: Mention gdb.execute change.
	* gdbcmd.h (execute_control_command): Don't declare.
	* python/python.c (execute_gdb_command): Use read_command_lines_1,
	execute_control_commands, execute_control_commands_to_string.
	* cli/cli-script.h (execute_control_commands)
	(execute_control_commands_to_string): Declare.
	(execute_control_command): Add from_tty parameter.
	* cli/cli-script.c (execute_control_commands)
	(execute_control_commands_to_string): New functions.
	(execute_user_command): Use execute_control_commands.
	(execute_control_command_1): Add "from_tty" parameter.  Update.
	(execute_control_command): Likewise.

gdb/testsuite/ChangeLog
2018-04-25  Tom Tromey  <tom@tromey.com>

	PR python/22730:
	* gdb.python/python.exp: Test multi-line execute.
---
 gdb/ChangeLog                       | 16 +++++++
 gdb/NEWS                            |  2 +
 gdb/cli/cli-script.c                | 93 ++++++++++++++++++++++++++-----------
 gdb/cli/cli-script.h                | 15 +++++-
 gdb/gdbcmd.h                        |  2 -
 gdb/python/python.c                 | 19 +++++++-
 gdb/testsuite/ChangeLog             |  5 ++
 gdb/testsuite/gdb.python/python.exp |  3 ++
 8 files changed, 123 insertions(+), 32 deletions(-)

diff --git a/gdb/NEWS b/gdb/NEWS
index 14d5fbb7c0..a72ee21cf8 100644
--- a/gdb/NEWS
+++ b/gdb/NEWS
@@ -29,6 +29,8 @@ set|show record btrace cpu
   ** The commands attached to a breakpoint can be set by assigning to
      the breakpoint's "commands" field.
 
+  ** gdb.execute can now execute multi-line gdb commands.
+
 * New targets
 
 RiscV ELF			riscv*-*-elf
diff --git a/gdb/cli/cli-script.c b/gdb/cli/cli-script.c
index e336c58ad0..a62e4fe1c1 100644
--- a/gdb/cli/cli-script.c
+++ b/gdb/cli/cli-script.c
@@ -374,12 +374,69 @@ execute_cmd_post_hook (struct cmd_list_element *c)
     }
 }
 
+/* See cli-script.h.  */
+
+void
+execute_control_commands (struct command_line *cmdlines, int from_tty)
+{
+  /* Set the instream to 0, indicating execution of a
+     user-defined function.  */
+  scoped_restore restore_instream
+    = make_scoped_restore (&current_ui->instream, nullptr);
+  scoped_restore save_async = make_scoped_restore (&current_ui->async, 0);
+  scoped_restore save_nesting
+    = make_scoped_restore (&command_nest_depth, command_nest_depth + 1);
+
+  while (cmdlines)
+    {
+      enum command_control_type ret = execute_control_command (cmdlines,
+							       from_tty);
+      if (ret != simple_control && ret != break_control)
+	{
+	  warning (_("Error executing canned sequence of commands."));
+	  break;
+	}
+      cmdlines = cmdlines->next;
+    }
+}
+
+/* See cli-script.h.  */
+
+std::string
+execute_control_commands_to_string (struct command_line *commands,
+				    int from_tty)
+{
+  /* GDB_STDOUT should be better already restored during these
+     restoration callbacks.  */
+  set_batch_flag_and_restore_page_info save_page_info;
+
+  string_file str_file;
+
+  {
+    current_uiout->redirect (&str_file);
+    ui_out_redirect_pop redirect_popper (current_uiout);
+
+    scoped_restore save_stdout
+      = make_scoped_restore (&gdb_stdout, &str_file);
+    scoped_restore save_stderr
+      = make_scoped_restore (&gdb_stderr, &str_file);
+    scoped_restore save_stdlog
+      = make_scoped_restore (&gdb_stdlog, &str_file);
+    scoped_restore save_stdtarg
+      = make_scoped_restore (&gdb_stdtarg, &str_file);
+    scoped_restore save_stdtargerr
+      = make_scoped_restore (&gdb_stdtargerr, &str_file);
+
+    execute_control_commands (commands, from_tty);
+  }
+
+  return std::move (str_file.string ());
+}
+
 void
 execute_user_command (struct cmd_list_element *c, const char *args)
 {
-  struct ui *ui = current_ui;
   counted_command_line cmdlines_copy;
-  enum command_control_type ret;
   extern unsigned int max_user_call_depth;
 
   /* Ensure that the user commands can't be deleted while they are
@@ -395,25 +452,7 @@ execute_user_command (struct cmd_list_element *c, const char *args)
   if (user_args_stack.size () > max_user_call_depth)
     error (_("Max user call depth exceeded -- command aborted."));
 
-  /* Set the instream to 0, indicating execution of a
-     user-defined function.  */
-  scoped_restore restore_instream
-    = make_scoped_restore (&ui->instream, nullptr);
-
-  scoped_restore save_async = make_scoped_restore (&current_ui->async, 0);
-
-  scoped_restore save_nesting
-    = make_scoped_restore (&command_nest_depth, command_nest_depth + 1);
-  while (cmdlines)
-    {
-      ret = execute_control_command (cmdlines);
-      if (ret != simple_control && ret != break_control)
-	{
-	  warning (_("Error executing canned sequence of commands."));
-	  break;
-	}
-      cmdlines = cmdlines->next;
-    }
+  execute_control_commands (cmdlines, 0);
 }
 
 /* This function is called every time GDB prints a prompt.  It ensures
@@ -465,7 +504,7 @@ print_command_trace (const char *fmt, ...)
 /* Helper for execute_control_command.  */
 
 static enum command_control_type
-execute_control_command_1 (struct command_line *cmd)
+execute_control_command_1 (struct command_line *cmd, int from_tty)
 {
   struct command_line *current;
   struct value *val;
@@ -483,7 +522,7 @@ execute_control_command_1 (struct command_line *cmd)
       {
 	/* A simple command, execute it and return.  */
 	std::string new_line = insert_user_defined_cmd_args (cmd->line);
-	execute_command (new_line.c_str (), 0);
+	execute_command (new_line.c_str (), from_tty);
 	ret = cmd->control_type;
 	break;
       }
@@ -538,7 +577,7 @@ execute_control_command_1 (struct command_line *cmd)
 	      {
 		scoped_restore save_nesting
 		  = make_scoped_restore (&command_nest_depth, command_nest_depth + 1);
-		ret = execute_control_command_1 (current);
+		ret = execute_control_command_1 (current, from_tty);
 
 		/* If we got an error, or a "break" command, then stop
 		   looping.  */
@@ -593,7 +632,7 @@ execute_control_command_1 (struct command_line *cmd)
 	  {
 	    scoped_restore save_nesting
 	      = make_scoped_restore (&command_nest_depth, command_nest_depth + 1);
-	    ret = execute_control_command_1 (current);
+	    ret = execute_control_command_1 (current, from_tty);
 
 	    /* If we got an error, get out.  */
 	    if (ret != simple_control)
@@ -644,7 +683,7 @@ execute_control_command_1 (struct command_line *cmd)
 }
 
 enum command_control_type
-execute_control_command (struct command_line *cmd)
+execute_control_command (struct command_line *cmd, int from_tty)
 {
   /* Make sure we use the console uiout.  It's possible that we are executing
      breakpoint commands while running the MI interpreter.  */
@@ -652,7 +691,7 @@ execute_control_command (struct command_line *cmd)
   scoped_restore save_uiout
     = make_scoped_restore (&current_uiout, interp_ui_out (console));
 
-  return execute_control_command_1 (cmd);
+  return execute_control_command_1 (cmd, from_tty);
 }
 
 /* Like execute_control_command, but first set
diff --git a/gdb/cli/cli-script.h b/gdb/cli/cli-script.h
index 3bebd0ed9d..736ebb3a7b 100644
--- a/gdb/cli/cli-script.h
+++ b/gdb/cli/cli-script.h
@@ -122,10 +122,23 @@ extern void show_user_1 (struct cmd_list_element *c,
 			 const char *name,
 			 struct ui_file *stream);
 
+/* Execute the commands in CMDLINES.  */
+
+extern void execute_control_commands (struct command_line *cmdlines,
+				      int from_tty);
+
+/* Run execute_control_commands for COMMANDS.  Capture its output into
+   the returned string, do not display it to the screen.  BATCH_FLAG
+   will be temporarily set to true.  */
+
+extern std::string execute_control_commands_to_string
+    (struct command_line *commands, int from_tty);
+
 /* Exported to gdb/breakpoint.c */
 
 extern enum command_control_type
-	execute_control_command (struct command_line *cmd);
+	execute_control_command (struct command_line *cmd,
+				 int from_tty = 0);
 
 extern enum command_control_type
 	execute_control_command_untraced (struct command_line *cmd);
diff --git a/gdb/gdbcmd.h b/gdb/gdbcmd.h
index 342c8b2c0e..b675ae8618 100644
--- a/gdb/gdbcmd.h
+++ b/gdb/gdbcmd.h
@@ -135,8 +135,6 @@ extern struct cmd_list_element *save_cmdlist;
 extern void execute_command (const char *, int);
 extern std::string execute_command_to_string (const char *p, int from_tty);
 
-enum command_control_type execute_control_command (struct command_line *);
-
 extern void print_command_line (struct command_line *, unsigned int,
 				struct ui_file *);
 extern void print_command_lines (struct ui_out *,
diff --git a/gdb/python/python.c b/gdb/python/python.c
index 45b6516fc2..befd3bb5aa 100644
--- a/gdb/python/python.c
+++ b/gdb/python/python.c
@@ -581,6 +581,20 @@ execute_gdb_command (PyObject *self, PyObject *args, PyObject *kw)
     {
       struct interp *interp;
 
+      std::string arg_copy = arg;
+      bool first = true;
+      char *save_ptr = nullptr;
+      auto reader
+	= [&] ()
+	  {
+	    const char *result = strtok_r (first ? &arg_copy[0] : nullptr,
+					   "\n", &save_ptr);
+	    first = false;
+	    return result;
+	  };
+
+      counted_command_line lines = read_command_lines_1 (reader, 1, nullptr);
+
       scoped_restore save_async = make_scoped_restore (&current_ui->async, 0);
 
       scoped_restore save_uiout = make_scoped_restore (&current_uiout);
@@ -592,9 +606,10 @@ execute_gdb_command (PyObject *self, PyObject *args, PyObject *kw)
 
       scoped_restore preventer = prevent_dont_repeat ();
       if (to_string)
-	to_string_res = execute_command_to_string (arg, from_tty);
+	to_string_res = execute_control_commands_to_string (lines.get (),
+							    from_tty);
       else
-	execute_command (arg, from_tty);
+	execute_control_commands (lines.get (), from_tty);
     }
   CATCH (except, RETURN_MASK_ALL)
     {
diff --git a/gdb/testsuite/gdb.python/python.exp b/gdb/testsuite/gdb.python/python.exp
index cee195f315..f6bf93add0 100644
--- a/gdb/testsuite/gdb.python/python.exp
+++ b/gdb/testsuite/gdb.python/python.exp
@@ -119,6 +119,9 @@ gdb_test_no_output \
     "python x = gdb.execute('printf \"%d\", 23', to_string = True)"
 gdb_test "python print (x)" "23"
 
+gdb_test "python gdb.execute('echo 2\\necho 3\\\\n\\n')" "23" \
+    "multi-line execute"
+
 # Test post_event.
 gdb_py_test_multiple "post event insertion" \
   "python" "" \
-- 
2.13.6