[PATCH v2 04/25] Introduce interpreter factories

[Pedro Alves <palves@redhat.com>]

If every UI instance has its own set of interpreters, then the current
scheme of creating the interpreters at GDB initialization time no
longer works.  We need to create them whenever a new UI instance is
created.

The scheme implemented here has each interpreter register an factory
callback that when called creates a new instance of a specific type.
Then, when some code in gdb looks up an interpreter (always by name),
if there's none yet, the factory method is called to construct one.

An alternative method I haven't tried would be to always create all
interpreters whenever a new UI instance is allocated.

I absolutely needed the lazy method in an earlier prototype of this
patch set, but it's not a requirement anymore.  Doesn't hurt though.
---
 gdb/cli/cli-interp.c | 83 +++++++++++++++++++++++++++++++-------------------
 gdb/interps.c        | 86 ++++++++++++++++++++++++++++++++++++++++++----------
 gdb/interps.h        | 11 ++++++-
 gdb/mi/mi-interp.c   | 36 +++++++++++++---------
 gdb/tui/tui-interp.c | 34 +++++++++++++--------
 5 files changed, 173 insertions(+), 77 deletions(-)

diff --git a/gdb/cli/cli-interp.c b/gdb/cli/cli-interp.c
index dfbd808..bd50af7 100644
--- a/gdb/cli/cli-interp.c
+++ b/gdb/cli/cli-interp.c
@@ -26,9 +26,14 @@
 #include "infrun.h"
 #include "observer.h"
 
-/* These are the ui_out and the interpreter for the console
-   interpreter.  */
-struct ui_out *cli_uiout;
+/* The console interpreter.  */
+struct cli_interp
+{
+  /* The ui_out for the console interpreter.  */
+  struct ui_out *cli_uiout;
+};
+
+/* The interpreter for the console interpreter.  */
 static struct interp *cli_interp;
 
 /* Longjmp-safe wrapper for "execute_command".  */
@@ -48,7 +53,7 @@ cli_on_normal_stop (struct bpstats *bs, int print_frame)
   if (!interp_quiet_p (cli_interp))
     {
       if (print_frame)
-	print_stop_event (cli_uiout);
+	print_stop_event (interp_ui_out (cli_interp));
     }
 }
 
@@ -58,7 +63,7 @@ static void
 cli_on_signal_received (enum gdb_signal siggnal)
 {
   if (!interp_quiet_p (cli_interp))
-    print_signal_received_reason (cli_uiout, siggnal);
+    print_signal_received_reason (interp_ui_out (cli_interp), siggnal);
 }
 
 /* Observer for the end_stepping_range notification.  */
@@ -67,7 +72,7 @@ static void
 cli_on_end_stepping_range (void)
 {
   if (!interp_quiet_p (cli_interp))
-    print_end_stepping_range_reason (cli_uiout);
+    print_end_stepping_range_reason (interp_ui_out (cli_interp));
 }
 
 /* Observer for the signalled notification.  */
@@ -76,7 +81,7 @@ static void
 cli_on_signal_exited (enum gdb_signal siggnal)
 {
   if (!interp_quiet_p (cli_interp))
-    print_signal_exited_reason (cli_uiout, siggnal);
+    print_signal_exited_reason (interp_ui_out (cli_interp), siggnal);
 }
 
 /* Observer for the exited notification.  */
@@ -85,7 +90,7 @@ static void
 cli_on_exited (int exitstatus)
 {
   if (!interp_quiet_p (cli_interp))
-    print_exited_reason (cli_uiout, exitstatus);
+    print_exited_reason (interp_ui_out (cli_interp), exitstatus);
 }
 
 /* Observer for the no_history notification.  */
@@ -94,7 +99,7 @@ static void
 cli_on_no_history (void)
 {
   if (!interp_quiet_p (cli_interp))
-    print_no_history_reason (cli_uiout);
+    print_no_history_reason (interp_ui_out (cli_interp));
 }
 
 /* Observer for the sync_execution_done notification.  */
@@ -120,6 +125,9 @@ cli_on_command_error (void)
 static void *
 cli_interpreter_init (struct interp *self, int top_level)
 {
+  if (top_level)
+    cli_interp = self;
+
   /* If changing this, remember to update tui-interp.c as well.  */
   observer_attach_normal_stop (cli_on_normal_stop);
   observer_attach_end_stepping_range (cli_on_end_stepping_range);
@@ -130,12 +138,13 @@ cli_interpreter_init (struct interp *self, int top_level)
   observer_attach_sync_execution_done (cli_on_sync_execution_done);
   observer_attach_command_error (cli_on_command_error);
 
-  return NULL;
+  return interp_data (self);
 }
 
 static int
 cli_interpreter_resume (void *data)
 {
+  struct cli_interp *cli = (struct cli_interp *) data;
   struct ui_file *stream;
 
   /*sync_execution = 1; */
@@ -144,17 +153,17 @@ cli_interpreter_resume (void *data)
      previously writing to gdb_stdout, then set it to the new
      gdb_stdout afterwards.  */
 
-  stream = cli_out_set_stream (cli_uiout, gdb_stdout);
+  stream = cli_out_set_stream (cli->cli_uiout, gdb_stdout);
   if (stream != gdb_stdout)
     {
-      cli_out_set_stream (cli_uiout, stream);
+      cli_out_set_stream (cli->cli_uiout, stream);
       stream = NULL;
     }
 
   gdb_setup_readline ();
 
   if (stream != NULL)
-    cli_out_set_stream (cli_uiout, gdb_stdout);
+    cli_out_set_stream (cli->cli_uiout, gdb_stdout);
 
   return 1;
 }
@@ -169,6 +178,7 @@ cli_interpreter_suspend (void *data)
 static struct gdb_exception
 cli_interpreter_exec (void *data, const char *command_str)
 {
+  struct cli_interp *cli = (struct cli_interp *) data;
   struct ui_file *old_stream;
   struct gdb_exception result;
 
@@ -184,9 +194,9 @@ cli_interpreter_exec (void *data, const char *command_str)
 
      It is important that it gets reset everytime, since the user
      could set gdb to use a different interpreter.  */
-  old_stream = cli_out_set_stream (cli_uiout, gdb_stdout);
-  result = safe_execute_command (cli_uiout, str, 1);
-  cli_out_set_stream (cli_uiout, old_stream);
+  old_stream = cli_out_set_stream (cli->cli_uiout, gdb_stdout);
+  result = safe_execute_command (cli->cli_uiout, str, 1);
+  cli_out_set_stream (cli->cli_uiout, old_stream);
   return result;
 }
 
@@ -222,7 +232,30 @@ safe_execute_command (struct ui_out *command_uiout, char *command, int from_tty)
 static struct ui_out *
 cli_ui_out (struct interp *self)
 {
-  return cli_uiout;
+  struct cli_interp *cli = (struct cli_interp *) interp_data (self);
+
+  return cli->cli_uiout;
+}
+
+static const struct interp_procs cli_interp_procs = {
+  cli_interpreter_init,		/* init_proc */
+  cli_interpreter_resume,	/* resume_proc */
+  cli_interpreter_suspend,	/* suspend_proc */
+  cli_interpreter_exec,		/* exec_proc */
+  cli_ui_out,			/* ui_out_proc */
+  NULL,                       	/* set_logging_proc */
+  cli_command_loop            	/* command_loop_proc */
+};
+
+static struct interp *
+cli_interp_factory (const char *name, struct ui *ui)
+{
+  struct cli_interp *cli = XNEW (struct cli_interp);
+
+  /* Create a default uiout builder for the CLI.  */
+  cli->cli_uiout = cli_out_new (gdb_stdout);
+
+  return interp_new (name, &cli_interp_procs, cli);
 }
 
 /* Standard gdb initialization hook.  */
@@ -231,19 +264,5 @@ extern initialize_file_ftype _initialize_cli_interp; /* -Wmissing-prototypes */
 void
 _initialize_cli_interp (void)
 {
-  static const struct interp_procs procs = {
-    cli_interpreter_init,	/* init_proc */
-    cli_interpreter_resume,	/* resume_proc */
-    cli_interpreter_suspend,	/* suspend_proc */
-    cli_interpreter_exec,	/* exec_proc */
-    cli_ui_out,			/* ui_out_proc */
-    NULL,                       /* set_logging_proc */
-    cli_command_loop            /* command_loop_proc */
-  };
-
-  /* Create a default uiout builder for the CLI.  */
-  cli_uiout = cli_out_new (gdb_stdout);
-  cli_interp = interp_new (INTERP_CONSOLE, &procs);
-
-  interp_add (cli_interp);
+  interp_factory_register (INTERP_CONSOLE, cli_interp_factory);
 }
diff --git a/gdb/interps.c b/gdb/interps.c
index 945b830..6626b4f 100644
--- a/gdb/interps.c
+++ b/gdb/interps.c
@@ -89,18 +89,20 @@ struct interp
 
 void _initialize_interpreter (void);
 
+static struct interp *interp_lookup_existing (const char *name);
+
 /* interp_new - This allocates space for a new interpreter,
    fills the fields from the inputs, and returns a pointer to the
    interpreter.  */
 struct interp *
-interp_new (const char *name, const struct interp_procs *procs)
+interp_new (const char *name, const struct interp_procs *procs, void *data)
 {
   struct interp *new_interp;
 
   new_interp = XNEW (struct interp);
 
   new_interp->name = xstrdup (name);
-  new_interp->data = NULL;
+  new_interp->data = data;
   new_interp->quiet_p = 0;
   new_interp->procs = procs;
   new_interp->inited = 0;
@@ -111,6 +113,32 @@ interp_new (const char *name, const struct interp_procs *procs)
   return new_interp;
 }
 
+struct interp_factory
+{
+  /* This is the name in "-i=" and set interpreter.  */
+  const char *name;
+
+  /* The function that creates the interpreter.  */
+  interp_factory_func func;
+};
+
+typedef struct interp_factory *interp_factory_p;
+DEF_VEC_P(interp_factory_p);
+
+static VEC(interp_factory_p) *interpreter_factories = NULL;
+
+void
+interp_factory_register (const char *name, interp_factory_func func)
+{
+  struct interp_factory *f = XNEW (struct interp_factory);
+
+  f->name = name;
+  f->func = func;
+
+  /* FIXME: assert that no factory for NAME is already registered.  */
+  VEC_safe_push (interp_factory_p, interpreter_factories, f);
+}
+
 /* Add interpreter INTERP to the gdb interpreter list.  The
    interpreter must not have previously been added.  */
 void
@@ -118,7 +146,7 @@ interp_add (struct interp *interp)
 {
   struct ui_interp_info *ui_interp = get_current_interp_info ();
 
-  gdb_assert (interp_lookup (interp->name) == NULL);
+  gdb_assert (interp_lookup_existing (interp->name) == NULL);
 
   interp->next = ui_interp->interp_list;
   ui_interp->interp_list = interp;
@@ -217,18 +245,15 @@ interp_set (struct interp *interp, int top_level)
   return 1;
 }
 
-/* interp_lookup - Looks up the interpreter for NAME.  If no such
-   interpreter exists, return NULL, otherwise return a pointer to the
-   interpreter.  */
-struct interp *
-interp_lookup (const char *name)
+/* Look up the interpreter for NAME.  If no such interpreter exists,
+   return NULL, otherwise return a pointer to the interpreter.  */
+
+static struct interp *
+interp_lookup_existing (const char *name)
 {
   struct ui_interp_info *ui_interp = get_current_interp_info ();
   struct interp *interp;
 
-  if (name == NULL || strlen (name) == 0)
-    return NULL;
-
   for (interp = ui_interp->interp_list;
        interp != NULL;
        interp = interp->next)
@@ -240,6 +265,35 @@ interp_lookup (const char *name)
   return NULL;
 }
 
+struct interp *
+interp_lookup (const char *name)
+{
+  struct ui *ui = current_ui;
+  struct interp_factory *factory;
+  struct interp *interp;
+  int ix;
+
+  if (name == NULL || strlen (name) == 0)
+    return NULL;
+
+  /* Only create each interpreter once per top level.  */
+  interp = interp_lookup_existing (name);
+  if (interp != NULL)
+    return interp;
+
+  for (ix = 0;
+       VEC_iterate (interp_factory_p, interpreter_factories, ix, factory);
+       ++ix)
+    if (strcmp (factory->name, name) == 0)
+      {
+	interp = factory->func (name, ui);
+	interp_add (interp);
+	return interp;
+      }
+
+  return NULL;
+}
+
 /* Returns the current interpreter.  */
 
 struct ui_out *
@@ -467,15 +521,15 @@ static VEC (char_ptr) *
 interpreter_completer (struct cmd_list_element *ignore,
 		       const char *text, const char *word)
 {
-  struct ui_interp_info *ui_interp = get_current_interp_info ();
+  struct interp_factory *interp;
   int textlen;
   VEC (char_ptr) *matches = NULL;
-  struct interp *interp;
+  int ix;
 
   textlen = strlen (text);
-  for (interp = ui_interp->interp_list;
-       interp != NULL;
-       interp = interp->next)
+  for (ix = 0;
+       VEC_iterate (interp_factory_p, interpreter_factories, ix, interp);
+       ++ix)
     {
       if (strncmp (interp->name, text, textlen) == 0)
 	{
diff --git a/gdb/interps.h b/gdb/interps.h
index f0badc5..f80e563 100644
--- a/gdb/interps.h
+++ b/gdb/interps.h
@@ -24,6 +24,13 @@
 
 struct ui_out;
 struct interp;
+struct ui;
+
+typedef struct interp *(*interp_factory_func) (const char *interp,
+					       struct ui *ui);
+
+extern void interp_factory_register (const char *name,
+				     interp_factory_func func);
 
 extern int interp_resume (struct interp *interp);
 extern int interp_suspend (struct interp *interp);
@@ -64,7 +71,9 @@ struct interp_procs
   interp_command_loop_ftype *command_loop_proc;
 };
 
-extern struct interp *interp_new (const char *name, const struct interp_procs *procs);
+extern struct interp *interp_new (const char *name,
+				  const struct interp_procs *procs,
+				  void *data);
 extern void interp_add (struct interp *interp);
 extern int interp_set (struct interp *interp, int top_level);
 extern struct interp *interp_lookup (const char *name);
diff --git a/gdb/mi/mi-interp.c b/gdb/mi/mi-interp.c
index 7ec51d3..06f1ae8 100644
--- a/gdb/mi/mi-interp.c
+++ b/gdb/mi/mi-interp.c
@@ -1134,25 +1134,31 @@ mi_set_logging (struct interp *interp, int start_log,
   return 1;
 }
 
+static const struct interp_procs mi_interp_procs =
+{
+  mi_interpreter_init,		/* init_proc */
+  mi_interpreter_resume,	/* resume_proc */
+  mi_interpreter_suspend,	/* suspend_proc */
+  mi_interpreter_exec,		/* exec_proc */
+  mi_ui_out, 			/* ui_out_proc */
+  mi_set_logging,		/* set_logging_proc */
+  mi_command_loop		/* command_loop_proc */
+};
+
+static struct interp *
+mi_interp_factory (const char *name, struct ui *ui)
+{
+  return interp_new (name, &mi_interp_procs, NULL);
+}
+
 extern initialize_file_ftype _initialize_mi_interp; /* -Wmissing-prototypes */
 
 void
 _initialize_mi_interp (void)
 {
-  static const struct interp_procs procs =
-    {
-      mi_interpreter_init,	/* init_proc */
-      mi_interpreter_resume,	/* resume_proc */
-      mi_interpreter_suspend,	/* suspend_proc */
-      mi_interpreter_exec,	/* exec_proc */
-      mi_ui_out, 		/* ui_out_proc */
-      mi_set_logging,		/* set_logging_proc */
-      mi_command_loop		/* command_loop_proc */
-    };
-
   /* The various interpreter levels.  */
-  interp_add (interp_new (INTERP_MI1, &procs));
-  interp_add (interp_new (INTERP_MI2, &procs));
-  interp_add (interp_new (INTERP_MI3, &procs));
-  interp_add (interp_new (INTERP_MI, &procs));
+  interp_factory_register (INTERP_MI1, mi_interp_factory);
+  interp_factory_register (INTERP_MI2, mi_interp_factory);
+  interp_factory_register (INTERP_MI3, mi_interp_factory);
+  interp_factory_register (INTERP_MI, mi_interp_factory);
 }
diff --git a/gdb/tui/tui-interp.c b/gdb/tui/tui-interp.c
index 7a0da48..c7910bc 100644
--- a/gdb/tui/tui-interp.c
+++ b/gdb/tui/tui-interp.c
@@ -138,6 +138,9 @@ tui_init (struct interp *self, int top_level)
   /* Install exit handler to leave the screen in a good shape.  */
   atexit (tui_exit);
 
+  if (top_level)
+    tui_interp = self;
+
   tui_initialize_static_data ();
 
   tui_initialize_io ();
@@ -207,25 +210,30 @@ tui_exec (void *data, const char *command_str)
   internal_error (__FILE__, __LINE__, _("tui_exec called"));
 }
 
+static const struct interp_procs tui_interp_procs = {
+  tui_init,
+  tui_resume,
+  tui_suspend,
+  tui_exec,
+  tui_ui_out,
+  NULL,
+  cli_command_loop
+};
+
+static struct interp *
+tui_interp_factory (const char *name, struct ui *ui)
+{
+  return interp_new (name, &tui_interp_procs, NULL);
+}
+
 /* Provide a prototype to silence -Wmissing-prototypes.  */
 extern initialize_file_ftype _initialize_tui_interp;
 
 void
 _initialize_tui_interp (void)
 {
-  static const struct interp_procs procs = {
-    tui_init,
-    tui_resume,
-    tui_suspend,
-    tui_exec,
-    tui_ui_out,
-    NULL,
-    cli_command_loop
-  };
-
-  /* Create a default uiout builder for the TUI.  */
-  tui_interp = interp_new (INTERP_TUI, &procs);
-  interp_add (tui_interp);
+  interp_factory_register (INTERP_TUI, tui_interp_factory);
+
   if (interpreter_p && strcmp (interpreter_p, INTERP_TUI) == 0)
     tui_start_enabled = 1;
 
-- 
2.5.0