Change how SIGALRM interrupts python.

Rather than setting an resetting alarm(), set the alarm() once and
set/clear a flag to say if python is running.
Then interrupt python only if it is running.

Signed-off-by: NeilBrown <[email protected]>

DOC/TODO.md

@@ -89,7 +89,7 @@ Core features
 - [ ] If a pane wants to block mouse events from parents, as lib-view
       does, it shouldn't need to catch all the combinations, or it
       should be much easier
-- [ ] gather memory usage stats per-pane and allow a dump
+- [ ] gather memory usage stats per-pane, ensure 0 on close, and allow a dump
 - [ ] show doc size in doc list - include undo size?
 - [X] Ensure all panes that should use "Free" properly, and find some
       way to encourage its use.
@@ -137,7 +137,7 @@ Core features
 - [ ] design a way for a keystroke to interrupt a long-running function.
 - [ ] extend Draw:measure protocol to allow constant-width-fonts to
       cannot-scale displays can be detected and measurement optimised for.
-- [ ] improve timeout.  Set timer once, then set a flag so that all commands fail
+- [X] improve timeout.  Set timer once, then set a flag so that all commands fail
       until some top-level clears the flag.
 - [ ] reconsider all 'return comm_call()' calls.  Do we every really
       care if the callback succeeded?
@@ -171,6 +171,7 @@ Core features
       the call which gave access to it, unless it registers for
       notifications from the owner, and that probably only applies to
       points.
+- [ ] do something useful on SIGINT - maybe expedite times_up().
 
 ### Longer term
 
@@ -182,7 +183,7 @@ Core features
 - [ ] support $SUBST in file-open path names ??
 - [ ] Need a debug mode where every mark usage is checked for validity.
       also check the setref sets up all linkages.
-- [ ] remove all FIXMEs (there are 65) ... and any HACKs (2).
+- [ ] remove all FIXMEs (there are 77) ... and any HACKs (5).
 - [ ] Replace asserts with warnings where possible.
 - [ ] hide view-num inside pane so number cannot be misused.
      i.e. each view is owned by a pane and can only be used by that pane.
@@ -369,7 +370,8 @@ Module features
 
 ### pygtk
 
-- [ ] can we capture the substates of character composition, and give feed-back?
+- [ ] can we capture the substates of character composition, and give
+      feed-back?
 
 ### display-x11-xcb
 
@@ -413,7 +415,7 @@ Module features
 
 ### lib-macro
 
-- [ ] don't allow starting macro inside a macro
+- [X] don't allow starting macro inside a macro
 - [ ] detect errors including Abort and search failure etc. Abort capture or
       replay on error
 - [ ] Possibly wait for a shell-command etc to complete before continuing.
@@ -443,7 +445,7 @@ Module features
 - [ ] things slow down after lots of edits.  Maybe track
       number of chunk, marks, undos etc and display them somewhere
 - [ ] stop consistency checking a doc when it gets "big" ??
-- [ ] avoid infinite loops in consistency checks
+- [X] avoid infinite loops in consistency checks
 - [ ] doc-text: opening file with e.g. 200,000 lines is very slow
       Check this..
 - [ ] moving in a big file is slow - check this
@@ -780,7 +782,7 @@ Module features
 ### lang-python
 
 - [ ] review python doc:char implementations for simplification.
-- [ ] repeated alarm(10)/alarm(0) calls slow things down
+- [X] repeated alarm(10)/alarm(0) calls slow things down
 - [ ] array index should allow two args, second being a mark for
       doc:get-attr etc.
 - [ ] should be able to test if a mark is NULL or Freed

core-editor.c

@@ -7,6 +7,7 @@
 #include <stdlib.h>
 #include <string.h>
 #include <stdio.h>
+#include <signal.h>
 #include <fcntl.h>
 #include <stdarg.h>
 #include <dlfcn.h>
@@ -202,7 +203,11 @@ DEF_CMD(editor_load_module)
 			return 1;
 		}
 #endif
-	if (key_lookup_prefix(map, ci) > 0)
+	/* Multiple modules can support module lookup, such as
+	 * global-load-modules:python or global-load-module:lua.
+	 * So do a prefix lookup.
+	 */
+	if (key_lookup_prefix(map, ci, False) > 0)
 		return 1;
 	LOG("Failed to load module: %s", name);
 	return Efail;
@@ -216,15 +221,15 @@ DEF_CMD(editor_auto_event)
 	 */
 	struct ed_info *ei = ci->home->data;
 	struct map *map = ei->map;
-	int ret = key_lookup_prefix(map, ci);
+	int ret = key_lookup_prefix(map, ci, False);
 
 	if (ret)
 		return ret;
 	if (strcmp(ci->key, "event:refresh") == 0)
 		/* pointless to autoload for refresh */
 		return Efallthrough;
 	call("attach-libevent", ci->home);
-	return key_lookup_prefix(map, ci);
+	return key_lookup_prefix(map, ci, False);
 }
 
 DEF_CMD(editor_activate_display)
@@ -278,7 +283,7 @@ DEF_CMD(editor_multicall)
 	const char *key = ci->key;
 
 	((struct cmd_info*)ci)->key = ksuffix(ci, "global-multicall-");
-	ret = key_lookup_prefix(map, ci);
+	ret = key_lookup_prefix(map, ci, False);
 	((struct cmd_info*)ci)->key = key;
 	return ret;
 }
@@ -686,6 +691,32 @@ DEF_CMD(global_find_file)
 	return Efalse;
 }
 
+static struct pane *editor;
+static void catch(int sig)
+{
+	struct cmd_info ci;
+	if (!editor)
+		return;
+	signal(sig, catch);
+	ci.home = editor;
+	ci.focus = editor;
+	ci.num = sig;
+	ci.num2 = 0;
+	ci.str = ci.str2 = NULL;
+	ci.mark = ci.mark2 = NULL;
+	ci.x = ci.y = 0;
+	switch (sig) {
+	case SIGALRM:
+		ci.key = "fast-alarm-";
+		key_lookup_prefix(editor->data->map, &ci, True);
+		break;
+	case SIGINT:
+		ci.key = "fast-interrupt-";
+		key_lookup_prefix(editor->data->map, &ci, True);
+		break;
+	}
+}
+
 struct pane *editor_new(const char *comm_name)
 {
 	struct pane *ed;
@@ -728,5 +759,9 @@ struct pane *editor_new(const char *comm_name)
 	log_setup(ed);
 	window_setup(ed);
 
+	signal(SIGINT, catch);
+	signal(SIGALRM, catch);
+
+	editor = ed;
 	return ed;
 }

core-keymap.c

@@ -491,8 +491,12 @@ int key_lookup(struct map *m safe, const struct cmd_info *ci safe)
 	}
 }
 
-int key_lookup_prefix(struct map *m safe, const struct cmd_info *ci safe)
+int key_lookup_prefix(struct map *m safe, const struct cmd_info *ci safe,
+		      bool simple)
 {
+	/* A "Simple" lookup avoids the backtrace.  It is used in
+	 * signal handlers.
+	 */
 	const char *k = ci->key;
 	int len = strlen(k);
 	int pos = key_find(m, k);
@@ -508,7 +512,10 @@ int key_lookup_prefix(struct map *m safe, const struct cmd_info *ci safe)
 		if (comm && comm != prev) {
 			((struct cmd_info*)ci)->comm = comm;
 			((struct cmd_info*)ci)->key = m->keys[pos+i];
-			ret = do_comm_call(comm, ci);
+			if (simple)
+				ret = comm->func(ci);
+			else
+				ret = do_comm_call(comm, ci);
 			ASSERT(ret >= Efallthrough || ret < Eunused);
 			prev = comm;
 			/* something might have been added, recalc

core-pane.h

@@ -1,3 +1,5 @@
+#include <unistd.h>
+
 struct pane {
 	const char		*name; /* For easy discovery in gdb */
 	struct pane		*parent safe;
@@ -69,10 +71,12 @@ static inline struct pane * safe pane_root(struct pane *p safe)
 static inline void time_starts(struct pane *p safe)
 {
 	pane_set_time(pane_root(p));
+	alarm(15);
 }
 
 static inline void time_ends(struct pane *p safe)
 {
+	alarm(0);
 	pane_end_time(pane_root(p));
 }
 

core.h

@@ -406,7 +406,8 @@ struct map *safe key_alloc(void);
 void key_free(struct map *m safe);
 int key_handle(const struct cmd_info *ci safe);
 int key_lookup(struct map *m safe, const struct cmd_info *ci safe);
-int key_lookup_prefix(struct map *m safe, const struct cmd_info *ci safe);
+int key_lookup_prefix(struct map *m safe, const struct cmd_info *ci safe,
+		      bool simple);
 struct command *key_lookup_cmd(struct map *m safe, const char *c safe);
 void key_add(struct map *map safe, const char *k safe, struct command *comm);
 void key_add_range(struct map *map safe,

lang-python.c

@@ -453,12 +453,12 @@ static int dict_add(PyObject *kwds, char *name, PyObject *val)
 	return 1;
 }
 
-static void python_interrupt(int sig)
+static bool python_running;
+DEF_CB(handle_alarm)
 {
-	/* Python code has been running for too long,
-	 * interrupt it.
-	 */
-	kill(getpid(), 2);
+	if (python_running)
+		PyErr_SetInterrupt();
+	return 1;
 }
 
 REDEF_CB(python_call)
@@ -516,11 +516,9 @@ REDEF_CB(python_call)
 			    Py_BuildValue("ii", ci->x, ci->y));
 
 	if (rv && pc->callable) {
-		signal(SIGALRM, python_interrupt);
-		alarm(10);
+		python_running = True;
 		ret = PyObject_Call(pc->callable, args, kwds);
-		alarm(0);
-		signal(SIGALRM, SIG_DFL);
+		python_running = False;
 	}
 
 	Py_DECREF(args);
@@ -1172,8 +1170,6 @@ static PyObject *Pane_call(Pane *self safe, PyObject *args safe, PyObject *kwds)
 	int rv;
 	PyObject *s1, *s2;
 	struct pyret pr;
-	int remain;
-	sighandler_t oldhan;
 
 	if (!pane_valid(self))
 		return NULL;
@@ -1187,13 +1183,9 @@ static PyObject *Pane_call(Pane *self safe, PyObject *args safe, PyObject *kwds)
 		return NULL;
 	}
 
-	remain = alarm(0);
-	oldhan = signal(SIGALRM, SIG_DFL);
+	python_running = False;
 	rv = key_handle(&ci);
-	if (oldhan != SIG_DFL) {
-		signal(SIGALRM, oldhan);
-		alarm(remain);
-	}
+	python_running = True;
 
 	/* Just in case ... */
 	PyErr_Clear();
@@ -2950,17 +2942,25 @@ void edlib_init(struct pane *ed safe)
 	PyObject *m;
 	PyConfig config;
 	char *argv[2]= { "edlib", NULL };
+	sighandler_t sigint;
 
 	if (edlib_module_path)
 		module_dir = strdup(edlib_module_path);
 	else
 		module_dir = ".";
 
+	/* de-register SIGINT while we initialise python,
+	 * so that Python thinks that it's registration is
+	 * valid - so PyErr_SetInterrupt() don't think there
+	 * is a race.
+	 */
+	sigint = signal(SIGINT, SIG_DFL);
 	PyConfig_InitPythonConfig(&config);
 	config.isolated = 1;
 	PyConfig_SetBytesArgv(&config, 0, argv);
 	Py_InitializeFromConfig(&config);
 	PyConfig_Clear(&config);
+	signal(SIGINT, sigint);
 
 	PaneType.tp_new = PyType_GenericNew;
 	PaneIterType.tp_new = PyType_GenericNew;
@@ -3030,6 +3030,9 @@ void edlib_init(struct pane *ed safe)
 	EdlibModule = m;
 	ed_pane = ed;
 
+	call_comm("global-set-command", ed, &handle_alarm,
+		  0, NULL, "fast-alarm-python");
+
 	call_comm("global-set-command", ed, &python_load_module,
 		  0, NULL, "global-load-modules:python");
 }