Introduce interpreter factories

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 a factory
callback that when called creates a new instance of a specific
interpreter 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.

gdb/ChangeLog:
2016-06-21  Pedro Alves  <palves@redhat.com>

	* cli/cli-interp.c (cli_uiout): Delete, moved into ...
	(struct cli_interp): ... this new structure.
	(cli_on_normal_stop, cli_on_signal_received)
	(cli_on_end_stepping_range, cli_on_signal_exited, cli_on_exited)
	(cli_on_no_history): Use interp_ui_out.
	(cli_interpreter_init): If top level, set the cli_interp global.
	(cli_interpreter_init): Return the interp's data instead of NULL.
	(cli_interpreter_resume, cli_interpreter_exec, cli_ui_out): Adjust
	to cli_uiout being in the interpreter's data.
	(cli_interp_procs): New, factored out from _initialize_cli_interp.
	(cli_interp_factory): New function.
	(_initialize_cli_interp): Call interp_factory_register.
	* interps.c (get_interp_info): New, factored out from ...
	(get_current_interp_info): ... this.
	(interp_new): Add parameter 'data'.  Store it.
	(struct interp_factory): New function.
	(interp_factory_p): New typedef.  Define a VEC_P.
	(interpreter_factories): New global.
	(interp_factory_register): New function.
	(interp_add): Add 'ui' parameter.  Use get_interp_info and
	interp_lookup_existing.
	(interp_lookup): Rename to ...
	(interp_lookup_existing): ... this.  Add 'ui' parameter.  Don't
	check for NULL or empty name here.
	(interp_lookup): Add 'ui' parameter and reimplement.
	(interp_set_temp, interpreter_exec_cmd): Adjust.
	(interpreter_completer): Complete on registered interpreter
	factories instead of interpreters.
	* interps.h (interp_factory_func): New typedef.
	(interp_factory_register): Declare.
	(interp_new, interp_add): Adjust.
	(interp_lookup): Declare.
	* main.c (captured_main): Adjust.
	* mi/mi-interp.c (mi_cmd_interpreter_exec): Adjust.
	(mi_interp_procs): New, factored out from
	_initialize_mi_interp.
	(mi_interp_factory): New function.
	* python/python.c (execute_gdb_command): Adjust.
	* tui/tui-interp.c (tui_init): If top level, set the tui_interp
	global.
	(tui_interp_procs): New.
	(tui_interp_factory): New function.
	(_initialize_tui_interp): Call interp_factory_register.

1 files changed, 105 insertions, 25 deletions

diff --git a/gdb/interps.c b/gdb/interps.c
index f19db54..fd08de5 100644
--- a/gdb/interps.c
+++ b/gdb/interps.c
@@ -53,18 +53,25 @@ struct ui_interp_info
   struct interp *command_interpreter;
 };
 
-/* Get the current UI's ui_interp_info object.  Never returns NULL.  */
+/* Get UI's ui_interp_info object.  Never returns NULL.  */
 
 static struct ui_interp_info *
-get_current_interp_info (void)
+get_interp_info (struct ui *ui)
 {
-  struct ui *ui = current_ui;
-
   if (ui->interp_info == NULL)
     ui->interp_info = XCNEW (struct ui_interp_info);
   return ui->interp_info;
 }
 
+/* Get the current UI's ui_interp_info object.  Never returns
+   NULL.  */
+
+static struct ui_interp_info *
+get_current_interp_info (void)
+{
+  return get_interp_info (current_ui);
+}
+
 struct interp
 {
   /* This is the name in "-i=" and set interpreter.  */
@@ -91,18 +98,21 @@ struct interp
 
 void _initialize_interpreter (void);
 
+static struct interp *interp_lookup_existing (struct ui *ui,
+					      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;
@@ -113,14 +123,57 @@ interp_new (const char *name, const struct interp_procs *procs)
   return new_interp;
 }
 
+/* An interpreter factory.  Maps an interpreter name to the factory
+   function that instantiates an interpreter by that name.  */
+
+struct interp_factory
+{
+  /* This is the name in "-i=INTERP" and "interpreter-exec INTERP".  */
+  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);
+
+/* The registered interpreter factories.  */
+static VEC(interp_factory_p) *interpreter_factories = NULL;
+
+/* See interps.h.  */
+
+void
+interp_factory_register (const char *name, interp_factory_func func)
+{
+  struct interp_factory *f;
+  int ix;
+
+  /* Assert that no factory for NAME is already registered.  */
+  for (ix = 0;
+       VEC_iterate (interp_factory_p, interpreter_factories, ix, f);
+       ++ix)
+    if (strcmp (f->name, name) == 0)
+      {
+	internal_error (__FILE__, __LINE__,
+			_("interpreter factory already registered: \"%s\"\n"),
+			name);
+      }
+
+  f = XNEW (struct interp_factory);
+  f->name = name;
+  f->func = func;
+  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
-interp_add (struct interp *interp)
+interp_add (struct ui *ui, struct interp *interp)
 {
-  struct ui_interp_info *ui_interp = get_current_interp_info ();
+  struct ui_interp_info *ui_interp = get_interp_info (ui);
 
-  gdb_assert (interp_lookup (interp->name) == NULL);
+  gdb_assert (interp_lookup_existing (ui, interp->name) == NULL);
 
   interp->next = ui_interp->interp_list;
   ui_interp->interp_list = interp;
@@ -219,18 +272,15 @@ 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 (struct ui *ui, const char *name)
 {
-  struct ui_interp_info *ui_interp = get_current_interp_info ();
+  struct ui_interp_info *ui_interp = get_interp_info (ui);
   struct interp *interp;
 
-  if (name == NULL || strlen (name) == 0)
-    return NULL;
-
   for (interp = ui_interp->interp_list;
        interp != NULL;
        interp = interp->next)
@@ -242,6 +292,36 @@ interp_lookup (const char *name)
   return NULL;
 }
 
+/* See interps.h.  */
+
+struct interp *
+interp_lookup (struct ui *ui, const char *name)
+{
+  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 (ui, 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);
+	interp_add (ui, interp);
+	return interp;
+      }
+
+  return NULL;
+}
+
 /* Returns the current interpreter.  */
 
 struct ui_out *
@@ -273,7 +353,7 @@ struct interp *
 interp_set_temp (const char *name)
 {
   struct ui_interp_info *ui_interp = get_current_interp_info ();
-  struct interp *interp = interp_lookup (name);
+  struct interp *interp = interp_lookup (current_ui, name);
   struct interp *old_interp = ui_interp->current_interpreter;
 
   if (interp)
@@ -433,7 +513,7 @@ interpreter_exec_cmd (char *args, int from_tty)
 
   old_interp = ui_interp->current_interpreter;
 
-  interp_to_use = interp_lookup (prules[0]);
+  interp_to_use = interp_lookup (current_ui, prules[0]);
   if (interp_to_use == NULL)
     error (_("Could not find interpreter \"%s\"."), prules[0]);
 
@@ -469,15 +549,15 @@ 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)
 	{