[RFAv3,1/6] Add previous_saved_command_line to allow a command to repeat a previous command.

Message ID 20190504161753.15530-2-philippe.waroquiers@skynet.be
State Superseded
Headers show
Series
  • Implement | (pipe) command.
Related show

Commit Message

Philippe Waroquiers May 4, 2019, 4:17 p.m.
Currently, a previous command can be repeated when the user types an
empty line.  This is implemented in handle_line_of_input by
returning saved_command_line in case an empty line has been input.

If we want a command to repeat the previous command, we need to save
the previous saved_command_line, as when a command runs, the saved_command_line
already contains the current command line of the command being executed.

As suggested by Tom, the previous_saved_command_line is made static.
At the same time, saved_command_line is also made static.
The support functions/variables for the repeat command logic are now all
located inside top.c.

gdb/ChangeLog
2019-05-04  Philippe Waroquiers  <philippe.waroquiers@skynet.be>

	* top.h (saved_command_line): Remove declaration.
	* top.c (previous_saved_command_line, previous_repeat_arguments):
	New variables.
	(saved_command_line): Make static, define together with other
	'repeat variables'.
	(dont_repeat): Clear repeat_arguments.
	(repeat_previous, get_saved_command_line, save_command_line):
	New functions.
	(gdb_init): Initialize saved_command_line
	and previous_saved_command_line.
	* main.c (captured_main_1): Remove saved_command_line initialization.
	* event-top.c (handle_line_of_input): Update to use
	the new 'repeat' related functions instead of direct access to
	saved_command_line.
	* command.h (repeat_previous, get_saved_command_line,
	save_command_line): New declarations.
	(dont_repeat): Add comment.
---
 gdb/command.h   | 36 ++++++++++++++++++++++++-
 gdb/event-top.c | 16 +++++------
 gdb/main.c      |  2 --
 gdb/top.c       | 70 +++++++++++++++++++++++++++++++++++++++++--------
 gdb/top.h       |  1 -
 5 files changed, 101 insertions(+), 24 deletions(-)

-- 
2.20.1

Comments

Pedro Alves May 27, 2019, 5:29 p.m. | #1
On 5/4/19 5:17 PM, Philippe Waroquiers wrote:
> Currently, a previous command can be repeated when the user types an

> empty line.  This is implemented in handle_line_of_input by

> returning saved_command_line in case an empty line has been input.

> 

> If we want a command to repeat the previous command, we need to save

> the previous saved_command_line, as when a command runs, the saved_command_line

> already contains the current command line of the command being executed.

> 

> As suggested by Tom, the previous_saved_command_line is made static.

> At the same time, saved_command_line is also made static.

> The support functions/variables for the repeat command logic are now all

> located inside top.c.

> 

> gdb/ChangeLog

> 2019-05-04  Philippe Waroquiers  <philippe.waroquiers@skynet.be>

> 

> 	* top.h (saved_command_line): Remove declaration.

> 	* top.c (previous_saved_command_line, previous_repeat_arguments):

> 	New variables.

> 	(saved_command_line): Make static, define together with other

> 	'repeat variables'.

> 	(dont_repeat): Clear repeat_arguments.

> 	(repeat_previous, get_saved_command_line, save_command_line):

> 	New functions.

> 	(gdb_init): Initialize saved_command_line

> 	and previous_saved_command_line.

> 	* main.c (captured_main_1): Remove saved_command_line initialization.

> 	* event-top.c (handle_line_of_input): Update to use

> 	the new 'repeat' related functions instead of direct access to

> 	saved_command_line.

> 	* command.h (repeat_previous, get_saved_command_line,

> 	save_command_line): New declarations.

> 	(dont_repeat): Add comment.

> ---

>  gdb/command.h   | 36 ++++++++++++++++++++++++-

>  gdb/event-top.c | 16 +++++------

>  gdb/main.c      |  2 --

>  gdb/top.c       | 70 +++++++++++++++++++++++++++++++++++++++++--------

>  gdb/top.h       |  1 -

>  5 files changed, 101 insertions(+), 24 deletions(-)

> 

> diff --git a/gdb/command.h b/gdb/command.h

> index 4a239a7196..ea3a58f81c 100644

> --- a/gdb/command.h

> +++ b/gdb/command.h

> @@ -448,7 +448,29 @@ extern void cmd_show_list (struct cmd_list_element *, int, const char *);

>  

>  extern void error_no_arg (const char *) ATTRIBUTE_NORETURN;

>  

> -extern void dont_repeat (void);

> +

> +/* Command line saving and repetition.

> +   Each input line executed is saved for possibly be repeated either


s/saved for ... be/saved to ... be/

> +   when the user types an empty line, or be repeated by a command

> +   that wants to repeat the previously executed command.  The below

> +   functions are controlling command repetition.  */


s/are controlling/control/

> +

> +/* Commands call dont_repeat if they do not want to be repeated by null

> +   lines or by repeat_previous ().  */

> +

> +extern void dont_repeat ();

> +

> +/* Command call repeat_previous if they want to repeat the previous command.


s/Command call/Commands call/

> +   Such commands repeating the previous command must indicate


s/Such commands repeating/Such commands that repeat/

> +   to not repeat themselves, to avoid recursive repeat.

> +   repeat_previous will mark the current command as not repeating,

> +   and will ensure get_saved_command_line returns the previous command,

> +   so that the currently executing command can repeat it.  */

> +

> +extern void repeat_previous ();

> +

> +/* Prevent dont_repeat from working, and return a cleanup that

> +   restores the previous state.  */

>  

>  extern scoped_restore_tmpl<int> prevent_dont_repeat (void);

>  

> @@ -457,6 +479,18 @@ extern scoped_restore_tmpl<int> prevent_dont_repeat (void);

>  

>  extern void set_repeat_arguments (const char *args);

>  

> +/* Returns the saved command line to repeat.

> +   When a command is being executed, this is the currently executing

> +   command line, unless the currently executing command has called

> +   repeat_previous (): in this case, get_saved_command_line returns

> +   the previously saved command line.  */

> +

> +extern char *get_saved_command_line ();

> +

> +/* Takes a copy of CMD, for possible repetition.  */

> +

> +extern void save_command_line (const char *cmd);

> +

>  /* Used to mark commands that don't do anything.  If we just leave the

>     function field NULL, the command is interpreted as a help topic, or

>     as a class of commands.  */

> diff --git a/gdb/event-top.c b/gdb/event-top.c

> index 3ccf136ff1..b64b7462c7 100644

> --- a/gdb/event-top.c

> +++ b/gdb/event-top.c

> @@ -634,11 +634,10 @@ command_line_append_input_line (struct buffer *cmd_line_buffer, const char *rl)

>     If REPEAT, handle command repetitions:

>  

>       - If the input command line is NOT empty, the command returned is

> -       copied into the global 'saved_command_line' var so that it can

> -       be repeated later.

> +       saved using save_command_line () so that it can be repeated later.

>  

> -     - OTOH, if the input command line IS empty, return the previously

> -       saved command instead of the empty input line.

> +     - OTOH, if the input command line IS empty, return the saved

> +       command instead of the empty input line.

>  */

>  

>  char *

> @@ -673,7 +672,7 @@ handle_line_of_input (struct buffer *cmd_line_buffer,

>    server_command = startswith (cmd, SERVER_COMMAND_PREFIX);

>    if (server_command)

>      {

> -      /* Note that we don't set `saved_command_line'.  Between this

> +      /* Note that we don't call `save_command_line'.  Between this

>           and the check in dont_repeat, this insures that repeating

>           will still do the right thing.  */

>        return cmd + strlen (SERVER_COMMAND_PREFIX);

> @@ -713,7 +712,7 @@ handle_line_of_input (struct buffer *cmd_line_buffer,

>    for (p1 = cmd; *p1 == ' ' || *p1 == '\t'; p1++)

>      ;

>    if (repeat && *p1 == '\0')

> -    return saved_command_line;

> +    return get_saved_command_line ();

>  

>    /* Add command to history if appropriate.  Note: lines consisting

>       solely of comments are also added to the command history.  This

> @@ -728,9 +727,8 @@ handle_line_of_input (struct buffer *cmd_line_buffer,

>    /* Save into global buffer if appropriate.  */

>    if (repeat)

>      {

> -      xfree (saved_command_line);

> -      saved_command_line = xstrdup (cmd);

> -      return saved_command_line;

> +      save_command_line (cmd);

> +      return get_saved_command_line ();

>      }

>    else

>      return cmd;

> diff --git a/gdb/main.c b/gdb/main.c

> index 35df1e497f..ef9bfe8fc6 100644

> --- a/gdb/main.c

> +++ b/gdb/main.c

> @@ -499,8 +499,6 @@ captured_main_1 (struct captured_main_args *context)

>  

>    notice_open_fds ();

>  

> -  saved_command_line = (char *) xstrdup ("");

> -

>  #ifdef __MINGW32__

>    /* Ensure stderr is unbuffered.  A Cygwin pty or pipe is implemented

>       as a Windows pipe, and Windows buffers on pipes.  */

> diff --git a/gdb/top.c b/gdb/top.c

> index bacd684dba..70f685ffad 100644

> --- a/gdb/top.c

> +++ b/gdb/top.c

> @@ -134,8 +134,26 @@ show_confirm (struct ui_file *file, int from_tty,

>  char *current_directory;

>  

>  /* The last command line executed on the console.  Used for command

> -   repetitions.  */

> -char *saved_command_line;

> +   repetitions when the user enters an empty line.  */

> +

> +static char *saved_command_line;

> +

> +/* If not NULL, the arguments that should be passed if

> +   saved_command_line is repeated.  */

> +

> +static const char *repeat_arguments;

> +

> +/* The previous last command line executed on the console.  Used for command

> +   repetitions when a command want to relaunch the previously launched


s/a command want/a command wants/

> +   command.  We need this as when a command is running, saved_command_line

> +   already contains the line of the currently executing command.  */

> +

> +char *previous_saved_command_line;

> +

> +/* If not NULL, the arguments that should be passed if the

> +   previous_saved_command_line is repeated.  */

> +

> +static const char *previous_repeat_arguments;

>  

>  /* Nonzero if the current command is modified by "server ".  This

>     affects things like recording into the command history, commands

> @@ -521,11 +539,6 @@ maybe_wait_sync_command_done (int was_sync)

>      wait_sync_command_done ();

>  }

>  

> -/* If not NULL, the arguments that should be passed if the current

> -   command is repeated.  */

> -

> -static const char *repeat_arguments;

> -

>  /* See command.h.  */

>  

>  void

> @@ -695,7 +708,7 @@ execute_command_to_string (const char *p, int from_tty,

>  

>  static int suppress_dont_repeat = 0;

>  

> -/* Commands call this if they do not want to be repeated by null lines.  */

> +/* See command.h  */

>  

>  void

>  dont_repeat (void)

> @@ -709,11 +722,27 @@ dont_repeat (void)

>       thing read from stdin in line and don't want to delete it.  Null

>       lines won't repeat here in any case.  */

>    if (ui->instream == ui->stdin_stream)

> -    *saved_command_line = 0;

> +    {

> +      *saved_command_line = 0;

> +      repeat_arguments = NULL;

> +    }

> +}

> +

> +/* See command.h  */

> +

> +void

> +repeat_previous ()

> +{

> +  /* Do not repeat this command, as this command is a repeating command.  */

> +  dont_repeat ();

> +

> +  /* We cannot free saved_command_line, as this line is being executed,

> +     so swap it with previous_saved_command_line.  */

> +  std::swap (previous_saved_command_line, saved_command_line);

> +  std::swap (previous_repeat_arguments, repeat_arguments);

>  }

>  

> -/* Prevent dont_repeat from working, and return a cleanup that

> -   restores the previous state.  */

> +/* See command.h.  */

>  

>  scoped_restore_tmpl<int>

>  prevent_dont_repeat (void)

> @@ -721,6 +750,22 @@ prevent_dont_repeat (void)

>    return make_scoped_restore (&suppress_dont_repeat, 1);

>  }

>  

> +char *

> +get_saved_command_line ()


Add usual /* See foo.h  */ comment.


> +{

> +  return saved_command_line;

> +}

> +

> +void

> +save_command_line (const char *cmd)


Ditto.

> +{

> +  xfree (previous_saved_command_line);

> +  previous_saved_command_line = saved_command_line;

> +  previous_repeat_arguments = repeat_arguments;

> +  saved_command_line = xstrdup (cmd);

> +  repeat_arguments = NULL;

> +}

> +

>  

>  /* Read a line from the stream "instream" without command line editing.

>  

> @@ -2179,6 +2224,9 @@ The second argument is the terminal the UI runs on.\n"), &cmdlist);

>  void

>  gdb_init (char *argv0)

>  {

> +  saved_command_line = (char *) xstrdup ("");

> +  previous_saved_command_line = (char *) xstrdup ("");


Drop the unnecessary casts.

> +

>    if (pre_init_ui_hook)

>      pre_init_ui_hook ();

>  

> diff --git a/gdb/top.h b/gdb/top.h

> index 025d9389d6..aab03c13d6 100644

> --- a/gdb/top.h

> +++ b/gdb/top.h

> @@ -217,7 +217,6 @@ extern void ui_register_input_event_handler (struct ui *ui);

>  extern void ui_unregister_input_event_handler (struct ui *ui);

>  

>  /* From top.c.  */

> -extern char *saved_command_line;

>  extern int confirm;

>  extern int inhibit_gdbinit;

>  extern const char gdbinit[];

> 

Thanks,
Pedro Alves

Patch

diff --git a/gdb/command.h b/gdb/command.h
index 4a239a7196..ea3a58f81c 100644
--- a/gdb/command.h
+++ b/gdb/command.h
@@ -448,7 +448,29 @@  extern void cmd_show_list (struct cmd_list_element *, int, const char *);
 
 extern void error_no_arg (const char *) ATTRIBUTE_NORETURN;
 
-extern void dont_repeat (void);
+
+/* Command line saving and repetition.
+   Each input line executed is saved for possibly be repeated either
+   when the user types an empty line, or be repeated by a command
+   that wants to repeat the previously executed command.  The below
+   functions are controlling command repetition.  */
+
+/* Commands call dont_repeat if they do not want to be repeated by null
+   lines or by repeat_previous ().  */
+
+extern void dont_repeat ();
+
+/* Command call repeat_previous if they want to repeat the previous command.
+   Such commands repeating the previous command must indicate
+   to not repeat themselves, to avoid recursive repeat.
+   repeat_previous will mark the current command as not repeating,
+   and will ensure get_saved_command_line returns the previous command,
+   so that the currently executing command can repeat it.  */
+
+extern void repeat_previous ();
+
+/* Prevent dont_repeat from working, and return a cleanup that
+   restores the previous state.  */
 
 extern scoped_restore_tmpl<int> prevent_dont_repeat (void);
 
@@ -457,6 +479,18 @@  extern scoped_restore_tmpl<int> prevent_dont_repeat (void);
 
 extern void set_repeat_arguments (const char *args);
 
+/* Returns the saved command line to repeat.
+   When a command is being executed, this is the currently executing
+   command line, unless the currently executing command has called
+   repeat_previous (): in this case, get_saved_command_line returns
+   the previously saved command line.  */
+
+extern char *get_saved_command_line ();
+
+/* Takes a copy of CMD, for possible repetition.  */
+
+extern void save_command_line (const char *cmd);
+
 /* Used to mark commands that don't do anything.  If we just leave the
    function field NULL, the command is interpreted as a help topic, or
    as a class of commands.  */
diff --git a/gdb/event-top.c b/gdb/event-top.c
index 3ccf136ff1..b64b7462c7 100644
--- a/gdb/event-top.c
+++ b/gdb/event-top.c
@@ -634,11 +634,10 @@  command_line_append_input_line (struct buffer *cmd_line_buffer, const char *rl)
    If REPEAT, handle command repetitions:
 
      - If the input command line is NOT empty, the command returned is
-       copied into the global 'saved_command_line' var so that it can
-       be repeated later.
+       saved using save_command_line () so that it can be repeated later.
 
-     - OTOH, if the input command line IS empty, return the previously
-       saved command instead of the empty input line.
+     - OTOH, if the input command line IS empty, return the saved
+       command instead of the empty input line.
 */
 
 char *
@@ -673,7 +672,7 @@  handle_line_of_input (struct buffer *cmd_line_buffer,
   server_command = startswith (cmd, SERVER_COMMAND_PREFIX);
   if (server_command)
     {
-      /* Note that we don't set `saved_command_line'.  Between this
+      /* Note that we don't call `save_command_line'.  Between this
          and the check in dont_repeat, this insures that repeating
          will still do the right thing.  */
       return cmd + strlen (SERVER_COMMAND_PREFIX);
@@ -713,7 +712,7 @@  handle_line_of_input (struct buffer *cmd_line_buffer,
   for (p1 = cmd; *p1 == ' ' || *p1 == '\t'; p1++)
     ;
   if (repeat && *p1 == '\0')
-    return saved_command_line;
+    return get_saved_command_line ();
 
   /* Add command to history if appropriate.  Note: lines consisting
      solely of comments are also added to the command history.  This
@@ -728,9 +727,8 @@  handle_line_of_input (struct buffer *cmd_line_buffer,
   /* Save into global buffer if appropriate.  */
   if (repeat)
     {
-      xfree (saved_command_line);
-      saved_command_line = xstrdup (cmd);
-      return saved_command_line;
+      save_command_line (cmd);
+      return get_saved_command_line ();
     }
   else
     return cmd;
diff --git a/gdb/main.c b/gdb/main.c
index 35df1e497f..ef9bfe8fc6 100644
--- a/gdb/main.c
+++ b/gdb/main.c
@@ -499,8 +499,6 @@  captured_main_1 (struct captured_main_args *context)
 
   notice_open_fds ();
 
-  saved_command_line = (char *) xstrdup ("");
-
 #ifdef __MINGW32__
   /* Ensure stderr is unbuffered.  A Cygwin pty or pipe is implemented
      as a Windows pipe, and Windows buffers on pipes.  */
diff --git a/gdb/top.c b/gdb/top.c
index bacd684dba..70f685ffad 100644
--- a/gdb/top.c
+++ b/gdb/top.c
@@ -134,8 +134,26 @@  show_confirm (struct ui_file *file, int from_tty,
 char *current_directory;
 
 /* The last command line executed on the console.  Used for command
-   repetitions.  */
-char *saved_command_line;
+   repetitions when the user enters an empty line.  */
+
+static char *saved_command_line;
+
+/* If not NULL, the arguments that should be passed if
+   saved_command_line is repeated.  */
+
+static const char *repeat_arguments;
+
+/* The previous last command line executed on the console.  Used for command
+   repetitions when a command want to relaunch the previously launched
+   command.  We need this as when a command is running, saved_command_line
+   already contains the line of the currently executing command.  */
+
+char *previous_saved_command_line;
+
+/* If not NULL, the arguments that should be passed if the
+   previous_saved_command_line is repeated.  */
+
+static const char *previous_repeat_arguments;
 
 /* Nonzero if the current command is modified by "server ".  This
    affects things like recording into the command history, commands
@@ -521,11 +539,6 @@  maybe_wait_sync_command_done (int was_sync)
     wait_sync_command_done ();
 }
 
-/* If not NULL, the arguments that should be passed if the current
-   command is repeated.  */
-
-static const char *repeat_arguments;
-
 /* See command.h.  */
 
 void
@@ -695,7 +708,7 @@  execute_command_to_string (const char *p, int from_tty,
 
 static int suppress_dont_repeat = 0;
 
-/* Commands call this if they do not want to be repeated by null lines.  */
+/* See command.h  */
 
 void
 dont_repeat (void)
@@ -709,11 +722,27 @@  dont_repeat (void)
      thing read from stdin in line and don't want to delete it.  Null
      lines won't repeat here in any case.  */
   if (ui->instream == ui->stdin_stream)
-    *saved_command_line = 0;
+    {
+      *saved_command_line = 0;
+      repeat_arguments = NULL;
+    }
+}
+
+/* See command.h  */
+
+void
+repeat_previous ()
+{
+  /* Do not repeat this command, as this command is a repeating command.  */
+  dont_repeat ();
+
+  /* We cannot free saved_command_line, as this line is being executed,
+     so swap it with previous_saved_command_line.  */
+  std::swap (previous_saved_command_line, saved_command_line);
+  std::swap (previous_repeat_arguments, repeat_arguments);
 }
 
-/* Prevent dont_repeat from working, and return a cleanup that
-   restores the previous state.  */
+/* See command.h.  */
 
 scoped_restore_tmpl<int>
 prevent_dont_repeat (void)
@@ -721,6 +750,22 @@  prevent_dont_repeat (void)
   return make_scoped_restore (&suppress_dont_repeat, 1);
 }
 
+char *
+get_saved_command_line ()
+{
+  return saved_command_line;
+}
+
+void
+save_command_line (const char *cmd)
+{
+  xfree (previous_saved_command_line);
+  previous_saved_command_line = saved_command_line;
+  previous_repeat_arguments = repeat_arguments;
+  saved_command_line = xstrdup (cmd);
+  repeat_arguments = NULL;
+}
+
 
 /* Read a line from the stream "instream" without command line editing.
 
@@ -2179,6 +2224,9 @@  The second argument is the terminal the UI runs on.\n"), &cmdlist);
 void
 gdb_init (char *argv0)
 {
+  saved_command_line = (char *) xstrdup ("");
+  previous_saved_command_line = (char *) xstrdup ("");
+
   if (pre_init_ui_hook)
     pre_init_ui_hook ();
 
diff --git a/gdb/top.h b/gdb/top.h
index 025d9389d6..aab03c13d6 100644
--- a/gdb/top.h
+++ b/gdb/top.h
@@ -217,7 +217,6 @@  extern void ui_register_input_event_handler (struct ui *ui);
 extern void ui_unregister_input_event_handler (struct ui *ui);
 
 /* From top.c.  */
-extern char *saved_command_line;
 extern int confirm;
 extern int inhibit_gdbinit;
 extern const char gdbinit[];