large rewrite of the extension matching code,

prerequisite to implement the specification defined yesterday.

While I have been using this code for months now, the change is large
so expect some instability.

Also the new specification (sorting extension by match length etc.)
is not implemented yet.



git-svn-id: http://svn.digium.com/svn/asterisk/trunk@25928 f38db490-d61c-443f-a65b-d21fe96a405b

1 files changed, 513 insertions, 563 deletions

diff --git a/pbx.c b/pbx.c
index 2821a9bbd..86e3c28e6 100644
--- a/pbx.c
+++ b/pbx.c
@@ -517,12 +517,6 @@ int pbx_exec(struct ast_channel *c, 		/*!< Channel */
 /*! Go no deeper than this through includes (not counting loops) */
 #define AST_PBX_MAX_STACK	128
 
-#define HELPER_EXISTS 0
-#define HELPER_SPAWN 1
-#define HELPER_CANMATCH 3
-#define HELPER_MATCHMORE 4
-#define HELPER_FINDLABEL 5
-
 /*! \brief Find application handle in linked list
  */
 struct ast_app *pbx_findapp(const char *app)
@@ -566,115 +560,143 @@ static void pbx_destroy(struct ast_pbx *p)
 	free(p);
 }
 
-#define EXTENSION_MATCH_CORE(data,pattern,match) {\
-	/* All patterns begin with _ */\
-	if (pattern[0] != '_') \
-		return 0;\
-	/* Start optimistic */\
-	match=1;\
-	pattern++;\
-	while(match && *data && *pattern && (*pattern != '/')) {\
-		while (*data == '-' && (*(data+1) != '\0')) data++;\
-		switch(toupper(*pattern)) {\
-		case '[': \
-		{\
-			int i,border=0;\
-			char *where;\
-			match=0;\
-			pattern++;\
-			where=strchr(pattern,']');\
-			if (where)\
-				border=(int)(where-pattern);\
-			if (!where || border > strlen(pattern)) {\
-				ast_log(LOG_WARNING, "Wrong usage of [] in the extension\n");\
-				return match;\
-			}\
-			for (i=0; i<border; i++) {\
-				int res=0;\
-				if (i+2<border)\
-					if (pattern[i+1]=='-') {\
-						if (*data >= pattern[i] && *data <= pattern[i+2]) {\
-							res=1;\
-						} else {\
-							i+=2;\
-							continue;\
-						}\
-					}\
-				if (res==1 || *data==pattern[i]) {\
-					match = 1;\
-					break;\
-				}\
-			}\
-			pattern+=border;\
-			break;\
-		}\
-		case 'N':\
-			if ((*data < '2') || (*data > '9'))\
-				match=0;\
-			break;\
-		case 'X':\
-			if ((*data < '0') || (*data > '9'))\
-				match = 0;\
-			break;\
-		case 'Z':\
-			if ((*data < '1') || (*data > '9'))\
-				match = 0;\
-			break;\
-		case '.':\
-			/* Must match */\
-			return 1;\
-		case '!':\
-			/* Early match */\
-			return 2;\
-		case ' ':\
-		case '-':\
-			/* Ignore these characters */\
-			data--;\
-			break;\
-		default:\
-			if (*data != *pattern)\
-				match =0;\
-		}\
-		data++;\
-		pattern++;\
-	}\
-	/* If we ran off the end of the data and the pattern ends in '!', match */\
-	if (match && !*data && (*pattern == '!'))\
-		return 2;\
+/*!
+ * When looking up extensions, we can have different requests
+ * identified by the 'action' argument, as follows.
+ * Note that the coding is such that the low 4 bits are the
+ * third argument to extension_match_core.
+ */
+enum ext_match_t {
+	E_MATCHMORE = 	0x00,	/* extension can match but only with more 'digits' */
+	E_CANMATCH =	0x01,	/* extension can match with or without more 'digits' */
+	E_MATCH =	0x02,	/* extension is an exact match */
+	E_MATCH_MASK =	0x03,	/* mask for the argument to extension_match_core() */
+	E_SPAWN =	0x12,	/* want to spawn an extension. Requires exact match */
+	E_FINDLABEL =	0x22	/* returns the priority for a given label. Requires exact match */
+};
+
+/*
+ * Internal function for ast_extension_{match|close}
+ * return 0 on no-match, 1 on match, 2 on early match.
+ * mode is as follows:
+ *	E_MATCH		success only on exact match
+ *	E_MATCHMORE	success only on partial match (i.e. leftover digits in pattern)
+ *	E_CANMATCH	either of the above.
+ */
+static int _extension_match_core(const char *pattern, const char *data, enum ext_match_t mode)
+{
+	mode &= E_MATCH_MASK;	/* only consider the relevant bits */
+
+	if (pattern[0] != '_') { /* not a pattern, try exact or partial match */
+		int ld = strlen(data), lp = strlen(pattern);
+
+		if (lp < ld)		/* pattern too short, cannot match */
+			return 0;
+		/* depending on the mode, accept full or partial match or both */
+		if (mode == E_MATCH)
+			return !strcmp(pattern, data); /* 1 on match, 0 on fail */
+		if (ld == 0 || !strncasecmp(pattern, data, ld)) /* partial or full match */
+			return (mode == E_MATCHMORE) ? lp > ld : 1; /* XXX should consider '!' and '/' ? */
+		else
+			return 0;
+	}
+	pattern++; /* skip leading _ */
+	while (*data && *pattern && *pattern != '/') {
+		const char *end;
+
+		if (*data == '-') { /* skip '-' in data (just a separator) */
+			data++;
+			continue;
+		}
+		switch (toupper(*pattern)) {
+		case '[':	/* a range */
+			end = strchr(pattern+1, ']'); /* XXX should deal with escapes ? */
+			if (end == NULL) {
+				ast_log(LOG_WARNING, "Wrong usage of [] in the extension\n");
+				return 0;	/* unconditional failure */
+			}
+			for (pattern++; pattern != end; pattern++) {
+				if (pattern+2 < end && pattern[1] == '-') { /* this is a range */
+					if (*data >= pattern[0] && *data <= pattern[2])
+						break;	/* match found */
+					else {
+						pattern += 2; /* skip a total of 3 chars */
+						continue;
+					}
+				} else if (*data == pattern[0])
+					break;	/* match found */
+			}
+			if (pattern == end)
+				return 0;
+			pattern = end;	/* skip and continue */
+			break;
+		case 'N':
+			if (*data < '2' || *data > '9')
+				return 0;
+			break;
+		case 'X':
+			if (*data < '0' || *data > '9')
+				return 0;
+			break;
+		case 'Z':
+			if (*data < '1' || *data > '9')
+				return 0;
+			break;
+		case '.':	/* Must match, even with more digits */
+			return 1;
+		case '!':	/* Early match */
+			return 2;
+		case ' ':
+		case '-':	/* Ignore these in patterns */
+			data--; /* compensate the final data++ */
+			break;
+		default:
+			if (*data != *pattern)
+				return 0;
+		}
+		data++;
+		pattern++;
+	}
+	if (*data)			/* data longer than pattern, no match */
+		return 0;
+	/*
+	 * match so far, but ran off the end of the data.
+	 * Depending on what is next, determine match or not.
+	 */
+	if (*pattern == '\0' || *pattern == '/')	/* exact match */
+		return (mode == E_MATCHMORE) ? 0 : 1;	/* this is a failure for E_MATCHMORE */
+	else if (*pattern == '!')			/* early match */
+		return 2;
+	else						/* partial match */
+		return (mode == E_MATCH) ? 0 : 1;	/* this is a failure for E_MATCH */
+}
+
+/*
+ * Wrapper around _extension_match_core() to do performance measurement
+ * using the profiling code.
+ */
+static int extension_match_core(const char *pattern, const char *data, enum ext_match_t mode)
+{
+	int i;
+	static int prof_id = -2;	/* marker for 'unallocated' id */
+	if (prof_id == -2)
+		prof_id = ast_add_profile("ext_match", 0);
+	ast_mark(prof_id, 1);
+	i = _extension_match_core(pattern, data, mode);
+	ast_mark(prof_id, 0);
+	return i;
 }
 
 int ast_extension_match(const char *pattern, const char *data)
 {
-	int match;
-	/* If they're the same return */
-	if (!strcmp(pattern, data))
-		return 1;
-	EXTENSION_MATCH_CORE(data,pattern,match);
-	/* Must be at the end of both */
-	if (*data || (*pattern && (*pattern != '/')))
-		match = 0;
-	return match;
+	return extension_match_core(pattern, data, E_MATCH);
 }
 
 int ast_extension_close(const char *pattern, const char *data, int needmore)
 {
-	int match;
-	/* If "data" is longer, it can'be a subset of pattern unless
-	   pattern is a pattern match */
-	if ((strlen(pattern) < strlen(data)) && (pattern[0] != '_'))
-		return 0;
-
-	if ((ast_strlen_zero((char *)data) || !strncasecmp(pattern, data, strlen(data))) &&
-		(!needmore || (strlen(pattern) > strlen(data)))) {
-		return 1;
-	}
-	EXTENSION_MATCH_CORE(data,pattern,match);
-	/* If there's more or we don't care about more, or if it's a possible early match,
-	   return non-zero; otherwise it's a miss */
-	if (!needmore || *pattern || match == 2) {
-		return match;
-	} else
-		return 0;
+	if (needmore != E_MATCHMORE && needmore != E_CANMATCH)
+		ast_log(LOG_WARNING, "invalid argument %d\n", needmore);
+	return extension_match_core(pattern, data, needmore);
 }
 
 struct ast_context *ast_context_find(const char *name)
@@ -726,35 +748,33 @@ struct pbx_find_info {
 };
 
 static struct ast_exten *pbx_find_extension(struct ast_channel *chan,
-	struct ast_context *bypass,
+	struct ast_context *bypass, struct pbx_find_info *q,
 	const char *context, const char *exten, int priority,
-	const char *label, const char *callerid, int action,
-	char *incstack[], int *stacklen, int *status, struct ast_switch **swo,
-	char **data, const char **foundcontext)
+	const char *label, const char *callerid, enum ext_match_t action)
 {
 	int x, res;
 	struct ast_context *tmp;
 	struct ast_exten *e, *eroot;
 	struct ast_include *i;
 	struct ast_sw *sw;
-	struct ast_switch *asw;
 
 	struct ast_exten *earlymatch = NULL;
 
 	/* Initialize status if appropriate */
-	if (!*stacklen) {
-		*status = STATUS_NO_CONTEXT;
-		*swo = NULL;
-		*data = NULL;
+	if (q->stacklen == 0) {
+		q->status = STATUS_NO_CONTEXT;
+		q->swo = NULL;
+		q->data = NULL;
+		q->foundcontext = NULL;
 	}
 	/* Check for stack overflow */
-	if (*stacklen >= AST_PBX_MAX_STACK) {
+	if (q->stacklen >= AST_PBX_MAX_STACK) {
 		ast_log(LOG_WARNING, "Maximum PBX stack exceeded\n");
 		return NULL;
 	}
 	/* Check first to see if we've already been checked */
-	for (x = 0; x < *stacklen; x++) {
-		if (!strcasecmp(incstack[x], context))
+	for (x = 0; x < q->stacklen; x++) {
+		if (!strcasecmp(q->incstack[x], context))
 			return NULL;
 	}
 	if (bypass)	/* bypass means we only look there */
@@ -767,37 +787,37 @@ static struct ast_exten *pbx_find_extension(struct ast_channel *chan,
 		if (!tmp)
 			return NULL;
 	}
-
-	if (*status < STATUS_NO_EXTENSION)
-		*status = STATUS_NO_EXTENSION;
+	if (q->status < STATUS_NO_EXTENSION)
+		q->status = STATUS_NO_EXTENSION;
 	for (eroot = tmp->root; eroot; eroot = eroot->next) {
-		int match = 0;
+		int match;
 		/* Match extension */
-		if ((((action != HELPER_MATCHMORE) && ast_extension_match(eroot->exten, exten)) ||
-		     ((action == HELPER_CANMATCH) && (ast_extension_close(eroot->exten, exten, 0))) ||
-		     ((action == HELPER_MATCHMORE) && (match = ast_extension_close(eroot->exten, exten, 1)))) &&
+		if ( (match = extension_match_core(eroot->exten, exten, action)) &&
 		     (!eroot->matchcid || matchcid(eroot->cidmatch, callerid))) {
 
-			if (action == HELPER_MATCHMORE && match == 2 && !earlymatch) {
+			if (action == E_MATCHMORE && match == 2 && !earlymatch) {
+				/* XXX not sure the logic is correct here.
+				 * we should go in irrespective of earlymatch
+				 */
 				/* It matched an extension ending in a '!' wildcard
 				   So ignore it for now, unless there's a better match */
 				earlymatch = eroot;
 			} else {
-				if (*status < STATUS_NO_PRIORITY)
-					*status = STATUS_NO_PRIORITY;
+				if (q->status < STATUS_NO_PRIORITY)
+					q->status = STATUS_NO_PRIORITY;
 				for (e = eroot; e; e = e->peer) {
 					/* Match priority */
-					if (action == HELPER_FINDLABEL) {
-						if (*status < STATUS_NO_LABEL)
-							*status = STATUS_NO_LABEL;
+					if (action == E_FINDLABEL) {
+						if (q->status < STATUS_NO_LABEL)
+							q->status = STATUS_NO_LABEL;
 						if (label && e->label && !strcmp(label, e->label)) {
-							*status = STATUS_SUCCESS;
-							*foundcontext = context;
+							q->status = STATUS_SUCCESS;
+							q->foundcontext = context;
 							return e;
 						}
 					} else if (e->priority == priority) {
-						*status = STATUS_SUCCESS;
-						*foundcontext = context;
+						q->status = STATUS_SUCCESS;
+						q->foundcontext = context;
 						return e;
 					}
 				}
@@ -805,7 +825,7 @@ static struct ast_exten *pbx_find_extension(struct ast_channel *chan,
 		}
 	}
 	if (earlymatch) {
-		/* Bizarre logic for HELPER_MATCHMORE. We return zero to break out
+		/* Bizarre logic for E_MATCHMORE. We return zero to break out
 		   of the loop waiting for more digits, and _then_ match (normally)
 		   the extension we ended up with. We got an early-matching wildcard
 		   pattern, so return NULL to break out of the loop. */
@@ -813,40 +833,45 @@ static struct ast_exten *pbx_find_extension(struct ast_channel *chan,
 	}
 	/* Check alternative switches */
 	AST_LIST_TRAVERSE(&tmp->alts, sw, list) {
-		if ((asw = pbx_findswitch(sw->name))) {
-			/* Substitute variables now */
-			if (sw->eval)
-				pbx_substitute_variables_helper(chan, sw->data, sw->tmpdata, SWITCH_DATA_LENGTH - 1);
-			if (action == HELPER_CANMATCH)
-				res = asw->canmatch ? asw->canmatch(chan, context, exten, priority, callerid, sw->eval ? sw->tmpdata : sw->data) : 0;
-			else if (action == HELPER_MATCHMORE)
-				res = asw->matchmore ? asw->matchmore(chan, context, exten, priority, callerid, sw->eval ? sw->tmpdata : sw->data) : 0;
-			else
-				res = asw->exists ? asw->exists(chan, context, exten, priority, callerid, sw->eval ? sw->tmpdata : sw->data) : 0;
-			if (res) {
-				/* Got a match */
-				*swo = asw;
-				*data = sw->eval ? sw->tmpdata : sw->data;
-				*foundcontext = context;
-				return NULL;
-			}
-		} else {
+		struct ast_switch *asw = pbx_findswitch(sw->name);
+		ast_switch_f *aswf = NULL;
+		char *datap;
+
+		if (!asw) {
 			ast_log(LOG_WARNING, "No such switch '%s'\n", sw->name);
+			continue;
+		}
+		/* Substitute variables now */
+		if (sw->eval)
+			pbx_substitute_variables_helper(chan, sw->data, sw->tmpdata, SWITCH_DATA_LENGTH - 1);
+
+		/* equivalent of extension_match_core() at the switch level */
+		if (action == E_CANMATCH)
+			aswf = asw->canmatch;
+		else if (action == E_MATCHMORE)
+			aswf = asw->matchmore;
+		else
+			aswf = asw->exists;
+		datap = sw->eval ? sw->tmpdata : sw->data;
+		res = !aswf ? 0 : aswf(chan, context, exten, priority, callerid, datap);
+		if (res) {	/* Got a match */
+			q->swo = asw;
+			q->data = datap;
+			q->foundcontext = context;
+			/* XXX keep status = STATUS_NO_CONTEXT ? */
+			return NULL;
 		}
 	}
-	/* Setup the stack */
-	incstack[*stacklen] = tmp->name;
-	(*stacklen)++;
+	q->incstack[q->stacklen++] = tmp->name;	/* Setup the stack */
 	/* Now try any includes we have in this context */
 	for (i = tmp->includes; i; i = i->next) {
 		if (include_valid(i)) {
-			if ((e = pbx_find_extension(chan, bypass, i->rname, exten, priority, label, callerid, action, incstack, stacklen, status, swo, data, foundcontext)))
+			if ((e = pbx_find_extension(chan, bypass, q, i->rname, exten, priority, label, callerid, action)))
 				return e;
-			if (*swo)
+			if (q->swo)
 				return NULL;
 		}
 	}
-
 	return NULL;
 }
 
@@ -1257,6 +1282,8 @@ int ast_func_write(struct ast_channel *chan, char *function, const char *value)
 
 static void pbx_substitute_variables_helper_full(struct ast_channel *c, struct varshead *headp, const char *cp1, char *cp2, int count)
 {
+	/* Substitutes variables into cp2, based on string cp1, and assuming cp2 to be
+	   zero-filled */
 	char *cp4;
 	const char *tmp, *whereweare;
 	int length, offset, offset2, isfunction;
@@ -1266,8 +1293,6 @@ static void pbx_substitute_variables_helper_full(struct ast_channel *c, struct v
 	char *vars, *vare;
 	int pos, brackets, needsub, len;
 
-	/* Substitutes variables into cp2, based on string cp1, and assuming cp2 to be
-	   zero-filled */
 	whereweare=tmp=cp1;
 	while (!ast_strlen_zero(whereweare) && count) {
 		/* Assume we're copying the whole remaining string */
@@ -1455,65 +1480,69 @@ static void pbx_substitute_variables(char *passdata, int datalen, struct ast_cha
 	pbx_substitute_variables_helper(c, e->data, passdata, datalen - 1);
 }
 
-static int pbx_extension_helper(struct ast_channel *c, struct ast_context *con, const char *context, const char *exten, int priority, const char *label, const char *callerid, int action)
+/*! \brief The return value depends on the action:
+ *
+ * E_MATCH, E_CANMATCH, E_MATCHMORE require a real match,
+ *	and return 0 on failure, -1 on match;
+ * E_FINDLABEL maps the label to a priority, and returns
+ *	the priority on success, ... XXX
+ * E_SPAWN, spawn an application,
+ *	and return 0 on success, -1 on failure.
+ */
+static int pbx_extension_helper(struct ast_channel *c, struct ast_context *con,
+	const char *context, const char *exten, int priority,
+	const char *label, const char *callerid, enum ext_match_t action)
 {
 	struct ast_exten *e;
 	struct ast_app *app;
-	struct ast_switch *sw;
-	char *data;
-	const char *foundcontext=NULL;
 	int res;
-	int status = 0;
-	char *incstack[AST_PBX_MAX_STACK];
+	struct pbx_find_info q = { .stacklen = 0 }; /* the rest is reset in pbx_find_extension */
 	char passdata[EXT_DATA_SIZE];
-	int stacklen = 0;
-	char tmp[80];
-	char tmp2[80];
-	char tmp3[EXT_DATA_SIZE];
-	char atmp[80];
-	char atmp2[EXT_DATA_SIZE+100];
 
-	ast_mutex_lock(&conlock);
+	int matching_action = (action == E_MATCH || action == E_CANMATCH || action == E_MATCHMORE);
 
-	e = pbx_find_extension(c, con, context, exten, priority, label, callerid, action, incstack, &stacklen, &status, &sw, &data, &foundcontext);
+	ast_mutex_lock(&conlock);
+	e = pbx_find_extension(c, con, &q, context, exten, priority, label, callerid, action);
 	if (e) {
-		switch(action) {
-		case HELPER_CANMATCH:
-			ast_mutex_unlock(&conlock);
-			return -1;
-		case HELPER_EXISTS:
+		if (matching_action) {
 			ast_mutex_unlock(&conlock);
-			return -1;
-		case HELPER_FINDLABEL:
+			return -1;	/* success, we found it */
+		} else if (action == E_FINDLABEL) { /* map the label to a priority */
 			res = e->priority;
 			ast_mutex_unlock(&conlock);
-			return res;
-		case HELPER_MATCHMORE:
-			ast_mutex_unlock(&conlock);
-			return -1;
-		case HELPER_SPAWN:
+			return res;	/* the priority we were looking for */
+		} else {	/* spawn */
 			app = pbx_findapp(e->app);
 			ast_mutex_unlock(&conlock);
-			if (app) {
-				if (c->context != context)
-					ast_copy_string(c->context, context, sizeof(c->context));
-				if (c->exten != exten)
-					ast_copy_string(c->exten, exten, sizeof(c->exten));
-				c->priority = priority;
-				pbx_substitute_variables(passdata, sizeof(passdata), c, e);
-				if (option_debug) {
-						ast_log(LOG_DEBUG, "Launching '%s'\n", app->name);
-						snprintf(atmp, 80, "STACK-%s-%s-%d", context, exten, priority);
-						snprintf(atmp2, EXT_DATA_SIZE+100, "%s(\"%s\", \"%s\") %s", app->name, c->name, passdata, "in new stack");
-						pbx_builtin_setvar_helper(c, atmp, atmp2);
-				}
-				if (option_verbose > 2)
-						ast_verbose( VERBOSE_PREFIX_3 "Executing %s(\"%s\", \"%s\") %s\n",
-								term_color(tmp, app->name, COLOR_BRCYAN, 0, sizeof(tmp)),
-								term_color(tmp2, c->name, COLOR_BRMAGENTA, 0, sizeof(tmp2)),
-								term_color(tmp3, passdata, COLOR_BRMAGENTA, 0, sizeof(tmp3)),
-								"in new stack");
-				manager_event(EVENT_FLAG_CALL, "Newexten",
+			if (!app) {
+				ast_log(LOG_WARNING, "No application '%s' for extension (%s, %s, %d)\n", e->app, context, exten, priority);
+				return -1;
+			}
+			if (c->context != context)
+				ast_copy_string(c->context, context, sizeof(c->context));
+			if (c->exten != exten)
+				ast_copy_string(c->exten, exten, sizeof(c->exten));
+			c->priority = priority;
+			pbx_substitute_variables(passdata, sizeof(passdata), c, e);
+			if (option_debug) {
+				char atmp[80];
+				char atmp2[EXT_DATA_SIZE+100];
+				ast_log(LOG_DEBUG, "Launching '%s'\n", app->name);
+				snprintf(atmp, sizeof(atmp), "STACK-%s-%s-%d", context, exten, priority);
+				snprintf(atmp2, sizeof(atmp2), "%s(\"%s\", \"%s\") %s",
+					app->name, c->name, passdata, "in new stack");
+				pbx_builtin_setvar_helper(c, atmp, atmp2);
+			}
+			if (option_verbose > 2) {
+				char tmp[80], tmp2[80], tmp3[EXT_DATA_SIZE];
+				ast_verbose( VERBOSE_PREFIX_3 "Executing [%s:%d] %s(\"%s\", \"%s\") %s\n",
+					context, priority,
+					term_color(tmp, app->name, COLOR_BRCYAN, 0, sizeof(tmp)),
+					term_color(tmp2, c->name, COLOR_BRMAGENTA, 0, sizeof(tmp2)),
+					term_color(tmp3, passdata, COLOR_BRMAGENTA, 0, sizeof(tmp3)),
+					"in new stack");
+			}
+			manager_event(EVENT_FLAG_CALL, "Newexten",
 					"Channel: %s\r\n"
 					"Context: %s\r\n"
 					"Extension: %s\r\n"
@@ -1522,56 +1551,32 @@ static int pbx_extension_helper(struct ast_channel *c, struct ast_context *con,
 					"AppData: %s\r\n"
 					"Uniqueid: %s\r\n",
 					c->name, c->context, c->exten, c->priority, app->name, passdata, c->uniqueid);
-				res = pbx_exec(c, app, passdata);
-				return res;
-			} else {
-				ast_log(LOG_WARNING, "No application '%s' for extension (%s, %s, %d)\n", e->app, context, exten, priority);
-				return -1;
-			}
-		default:
-			ast_log(LOG_WARNING, "Huh (%d)?\n", action);
-			return -1;
+			return pbx_exec(c, app, passdata);	/* 0 on success, -1 on failure */
 		}
-	} else if (sw) {
-		switch(action) {
-		case HELPER_CANMATCH:
-			ast_mutex_unlock(&conlock);
-			return -1;
-		case HELPER_EXISTS:
-			ast_mutex_unlock(&conlock);
-			return -1;
-		case HELPER_MATCHMORE:
-			ast_mutex_unlock(&conlock);
-			return -1;
-		case HELPER_FINDLABEL:
-			ast_mutex_unlock(&conlock);
+	} else if (q.swo) {	/* not found here, but in another switch */
+		ast_mutex_unlock(&conlock);
+		if (matching_action)
 			return -1;
-		case HELPER_SPAWN:
-			ast_mutex_unlock(&conlock);
-			if (sw->exec)
-				res = sw->exec(c, foundcontext ? foundcontext : context, exten, priority, callerid, data);
-			else {
-				ast_log(LOG_WARNING, "No execution engine for switch %s\n", sw->name);
+		else {
+			if (!q.swo->exec) {
+				ast_log(LOG_WARNING, "No execution engine for switch %s\n", q.swo->name);
 				res = -1;
 			}
-			return res;
-		default:
-			ast_log(LOG_WARNING, "Huh (%d)?\n", action);
-			return -1;
+			return q.swo->exec(c, q.foundcontext ? q.foundcontext : context, exten, priority, callerid, q.data);
 		}
-	} else {
+	} else {	/* not found anywhere, see what happened */
 		ast_mutex_unlock(&conlock);
-		switch(status) {
+		switch (q.status) {
 		case STATUS_NO_CONTEXT:
-			if ((action != HELPER_EXISTS) && (action != HELPER_MATCHMORE))
+			if (!matching_action)
 				ast_log(LOG_NOTICE, "Cannot find extension context '%s'\n", context);
 			break;
 		case STATUS_NO_EXTENSION:
-			if ((action != HELPER_EXISTS) && (action !=  HELPER_CANMATCH) && (action != HELPER_MATCHMORE))
+			if (!matching_action)
 				ast_log(LOG_NOTICE, "Cannot find extension '%s' in context '%s'\n", exten, context);
 			break;
 		case STATUS_NO_PRIORITY:
-			if ((action != HELPER_EXISTS) && (action !=  HELPER_CANMATCH) && (action != HELPER_MATCHMORE))
+			if (!matching_action)
 				ast_log(LOG_NOTICE, "No such priority %d in extension '%s' in context '%s'\n", priority, exten, context);
 			break;
 		case STATUS_NO_LABEL:
@@ -1582,27 +1587,18 @@ static int pbx_extension_helper(struct ast_channel *c, struct ast_context *con,
 			ast_log(LOG_DEBUG, "Shouldn't happen!\n");
 		}
 
-		if ((action != HELPER_EXISTS) && (action != HELPER_CANMATCH) && (action != HELPER_MATCHMORE))
-			return -1;
-		else
-			return 0;
+		return (matching_action) ? 0 : -1;
 	}
-
 }
 
 /*! \brief  ast_hint_extension: Find hint for given extension in context */
 static struct ast_exten *ast_hint_extension(struct ast_channel *c, const char *context, const char *exten)
 {
 	struct ast_exten *e;
-	struct ast_switch *sw;
-	char *data;
-	const char *foundcontext = NULL;
-	int status = 0;
-	char *incstack[AST_PBX_MAX_STACK];
-	int stacklen = 0;
+	struct pbx_find_info q = { .stacklen = 0 }; /* the rest is set in pbx_find_context */
 
 	ast_mutex_lock(&conlock);
-	e = pbx_find_extension(c, NULL, context, exten, PRIORITY_HINT, NULL, "", HELPER_EXISTS, incstack, &stacklen, &status, &sw, &data, &foundcontext);
+	e = pbx_find_extension(c, NULL, &q, context, exten, PRIORITY_HINT, NULL, "", E_MATCH);
 	ast_mutex_unlock(&conlock);
 
 	return e;
@@ -1965,32 +1961,32 @@ int ast_get_hint(char *hint, int hintsize, char *name, int namesize, struct ast_
 
 int ast_exists_extension(struct ast_channel *c, const char *context, const char *exten, int priority, const char *callerid)
 {
-	return pbx_extension_helper(c, NULL, context, exten, priority, NULL, callerid, HELPER_EXISTS);
+	return pbx_extension_helper(c, NULL, context, exten, priority, NULL, callerid, E_MATCH);
 }
 
 int ast_findlabel_extension(struct ast_channel *c, const char *context, const char *exten, const char *label, const char *callerid)
 {
-	return pbx_extension_helper(c, NULL, context, exten, 0, label, callerid, HELPER_FINDLABEL);
+	return pbx_extension_helper(c, NULL, context, exten, 0, label, callerid, E_FINDLABEL);
 }
 
 int ast_findlabel_extension2(struct ast_channel *c, struct ast_context *con, const char *exten, const char *label, const char *callerid)
 {
-	return pbx_extension_helper(c, con, NULL, exten, 0, label, callerid, HELPER_FINDLABEL);
+	return pbx_extension_helper(c, con, NULL, exten, 0, label, callerid, E_FINDLABEL);
 }
 
 int ast_canmatch_extension(struct ast_channel *c, const char *context, const char *exten, int priority, const char *callerid)
 {
-	return pbx_extension_helper(c, NULL, context, exten, priority, NULL, callerid, HELPER_CANMATCH);
+	return pbx_extension_helper(c, NULL, context, exten, priority, NULL, callerid, E_CANMATCH);
 }
 
 int ast_matchmore_extension(struct ast_channel *c, const char *context, const char *exten, int priority, const char *callerid)
 {
-	return pbx_extension_helper(c, NULL, context, exten, priority, NULL, callerid, HELPER_MATCHMORE);
+	return pbx_extension_helper(c, NULL, context, exten, priority, NULL, callerid, E_MATCHMORE);
 }
 
 int ast_spawn_extension(struct ast_channel *c, const char *context, const char *exten, int priority, const char *callerid)
 {
-	return pbx_extension_helper(c, NULL, context, exten, priority, NULL, callerid, HELPER_SPAWN);
+	return pbx_extension_helper(c, NULL, context, exten, priority, NULL, callerid, E_SPAWN);
 }
 
 /* helper function to set extension and priority */
@@ -2000,15 +1996,42 @@ static void set_ext_pri(struct ast_channel *c, const char *exten, int pri)
 	c->priority = pri;
 }
 
-static int __ast_pbx_run(struct ast_channel *c)
+/*!
+ * \brief collect digits from the channel into the buffer,
+ * return -1 on error, 0 on timeout or done.
+ */
+static int collect_digits(struct ast_channel *c, int waittime, char *buf, int buflen, int pos)
 {
-	int firstpass = 1;
 	int digit;
-	char exten[256];
-	int pos;
-	int waittime;
-	int res=0;
+
+	buf[pos] = '\0';	/* make sure it is properly terminated */
+	while (ast_matchmore_extension(c, c->context, buf, 1, c->cid.cid_num)) {
+		/* As long as we're willing to wait, and as long as it's not defined,
+		   keep reading digits until we can't possibly get a right answer anymore.  */
+		digit = ast_waitfordigit(c, waittime * 1000);
+		if (c->_softhangup == AST_SOFTHANGUP_ASYNCGOTO) {
+			c->_softhangup = 0;
+		} else {
+			if (!digit)	/* No entry */
+				break;
+			if (digit < 0)	/* Error, maybe a  hangup */
+				return -1;
+			if (pos < buflen - 1) {	/* XXX maybe error otherwise ? */
+				buf[pos++] = digit;
+				buf[pos] = '\0';
+			}
+			waittime = c->pbx->dtimeout;
+		}
+	}
+	return 0;
+}
+
+static int __ast_pbx_run(struct ast_channel *c)
+{
+	int found = 0;	/* set if we find at least one match */
+	int res = 0;
 	int autoloopflag;
+	int error = 0;		/* set an error conditions */
 
 	/* A little initial setup here */
 	if (c->pbx) {
@@ -2056,46 +2079,43 @@ static int __ast_pbx_run(struct ast_channel *c)
 	if (c->cdr && ast_tvzero(c->cdr->start))
 		ast_cdr_start(c->cdr);
 	for (;;) {
-		pos = 0;
-		digit = 0;
+		char dst_exten[256];	/* buffer to accumulate digits */
+		int pos = 0;		/* XXX should check bounds */
+		int digit = 0;
+
+		/* loop on priorities in this context/exten */
 		while (ast_exists_extension(c, c->context, c->exten, c->priority, c->cid.cid_num)) {
-			memset(exten, 0, sizeof(exten));
+			found = 1;
 			if ((res = ast_spawn_extension(c, c->context, c->exten, c->priority, c->cid.cid_num))) {
 				/* Something bad happened, or a hangup has been requested. */
-				if (((res >= '0') && (res <= '9')) || ((res >= 'A') && (res <= 'F')) ||
-					(res == '*') || (res == '#')) {
+				if (strchr("0123456789ABCDEF*#", res)) {
 					ast_log(LOG_DEBUG, "Oooh, got something to jump out with ('%c')!\n", res);
-					memset(exten, 0, sizeof(exten));
 					pos = 0;
-					exten[pos++] = digit = res;
+					dst_exten[pos++] = digit = res;
+					dst_exten[pos] = '\0';
 					break;
 				}
-				switch(res) {
-				case AST_PBX_KEEPALIVE:
+				if (res == AST_PBX_KEEPALIVE) {
 					if (option_debug)
 						ast_log(LOG_DEBUG, "Spawn extension (%s,%s,%d) exited KEEPALIVE on '%s'\n", c->context, c->exten, c->priority, c->name);
 					else if (option_verbose > 1)
 						ast_verbose( VERBOSE_PREFIX_2 "Spawn extension (%s, %s, %d) exited KEEPALIVE on '%s'\n", c->context, c->exten, c->priority, c->name);
-					goto out;
+					error = 1;
 					break;
-				default:
-					if (option_debug)
-						ast_log(LOG_DEBUG, "Spawn extension (%s,%s,%d) exited non-zero on '%s'\n", c->context, c->exten, c->priority, c->name);
-					else if (option_verbose > 1)
-						ast_verbose( VERBOSE_PREFIX_2 "Spawn extension (%s, %s, %d) exited non-zero on '%s'\n", c->context, c->exten, c->priority, c->name);
-					if (c->_softhangup == AST_SOFTHANGUP_ASYNCGOTO) {
-						c->_softhangup =0;
-						break;
-					}
-					/* atimeout */
-					if (c->_softhangup == AST_SOFTHANGUP_TIMEOUT) {
-						break;
-					}
-
-					if (c->cdr) {
+				}
+				if (option_debug)
+					ast_log(LOG_DEBUG, "Spawn extension (%s,%s,%d) exited non-zero on '%s'\n", c->context, c->exten, c->priority, c->name);
+				else if (option_verbose > 1)
+					ast_verbose( VERBOSE_PREFIX_2 "Spawn extension (%s, %s, %d) exited non-zero on '%s'\n", c->context, c->exten, c->priority, c->name);
+				if (c->_softhangup == AST_SOFTHANGUP_ASYNCGOTO) {
+					c->_softhangup =0;
+				} else if (c->_softhangup == AST_SOFTHANGUP_TIMEOUT) {
+					/* atimeout, nothing bad */
+				} else {
+					if (c->cdr)
 						ast_cdr_update(c);
-					}
-					goto out;
+					error = 1;
+					break;
 				}
 			}
 			if (c->_softhangup == AST_SOFTHANGUP_TIMEOUT && ast_exists_extension(c,c->context,"T",1,c->cid.cid_num)) {
@@ -2106,11 +2126,16 @@ static int __ast_pbx_run(struct ast_channel *c)
 			} else if (c->_softhangup) {
 				ast_log(LOG_DEBUG, "Extension %s, priority %d returned normally even though call was hung up\n",
 					c->exten, c->priority);
-				goto out;
+				error = 1;
+				break;
 			}
-			firstpass = 0;
 			c->priority++;
-		}
+		} /* end while  - from here on we can use 'break' to go out */
+		if (error)
+			break;
+
+		/* XXX we get here on non-existing extension or a keypress or hangup ? */
+
 		if (!ast_exists_extension(c, c->context, c->exten, 1, c->cid.cid_num)) {
 			/* If there is no match at priority 1, it is not a valid extension anymore.
 			 * Try to continue at "i", 1 or exit if the latter does not exist.
@@ -2123,73 +2148,20 @@ static int __ast_pbx_run(struct ast_channel *c)
 			} else {
 				ast_log(LOG_WARNING, "Channel '%s' sent into invalid extension '%s' in context '%s', but no invalid handler\n",
 					c->name, c->exten, c->context);
-				goto out;
+				error = 1; /* we know what to do with it */
+				break;
 			}
 		} else if (c->_softhangup == AST_SOFTHANGUP_TIMEOUT) {
 			/* If we get this far with AST_SOFTHANGUP_TIMEOUT, then we know that the "T" extension is next. */
 			c->_softhangup = 0;
-		} else {
-			/* Done, wait for an extension */
-			waittime = 0;
+		} else {	/* keypress received, get more digits for a full extension */
+			int waittime = 0;
 			if (digit)
 				waittime = c->pbx->dtimeout;
 			else if (!autofallthrough)
 				waittime = c->pbx->rtimeout;
-			if (waittime) {
-				while (ast_matchmore_extension(c, c->context, exten, 1, c->cid.cid_num)) {
-					/* As long as we're willing to wait, and as long as it's not defined,
-					   keep reading digits until we can't possibly get a right answer anymore.  */
-					digit = ast_waitfordigit(c, waittime * 1000);
-					if (c->_softhangup == AST_SOFTHANGUP_ASYNCGOTO) {
-						c->_softhangup = 0;
-					} else {
-						if (!digit)
-							/* No entry */
-							break;
-						if (digit < 0)
-							/* Error, maybe a  hangup */
-							goto out;
-						exten[pos++] = digit;
-						waittime = c->pbx->dtimeout;
-					}
-				}
-				if (ast_exists_extension(c, c->context, exten, 1, c->cid.cid_num)) {
-					/* Prepare the next cycle */
-					set_ext_pri(c, exten, 1);
-				} else {
-					/* No such extension */
-					if (!ast_strlen_zero(exten)) {
-						/* An invalid extension */
-						if (ast_exists_extension(c, c->context, "i", 1, c->cid.cid_num)) {
-							if (option_verbose > 2)
-								ast_verbose( VERBOSE_PREFIX_3 "Invalid extension '%s' in context '%s' on %s\n", exten, c->context, c->name);
-							pbx_builtin_setvar_helper(c, "INVALID_EXTEN", exten);
-							set_ext_pri(c, "i", 1);
-						} else {
-							ast_log(LOG_WARNING, "Invalid extension '%s', but no rule 'i' in context '%s'\n", exten, c->context);
-							goto out;
-						}
-					} else {
-						/* A simple timeout */
-						if (ast_exists_extension(c, c->context, "t", 1, c->cid.cid_num)) {
-							if (option_verbose > 2)
-								ast_verbose( VERBOSE_PREFIX_3 "Timeout on %s\n", c->name);
-							set_ext_pri(c, "t", 1);
-						} else {
-							ast_log(LOG_WARNING, "Timeout, but no rule 't' in context '%s'\n", c->context);
-							goto out;
-						}
-					}
-				}
-				if (c->cdr) {
-					if (option_verbose > 2)
-						ast_verbose(VERBOSE_PREFIX_2 "CDR updated on %s\n",c->name);
-					ast_cdr_update(c);
-			    }
-			} else {
-				const char *status;
-
-				status = pbx_builtin_getvar_helper(c, "DIALSTATUS");
+			if (!waittime) {
+				const char *status = pbx_builtin_getvar_helper(c, "DIALSTATUS");
 				if (!status)
 					status = "UNKNOWN";
 				if (option_verbose > 2)
@@ -2200,13 +2172,50 @@ static int __ast_pbx_run(struct ast_channel *c)
 					res = pbx_builtin_congestion(c, "10");
 				else if (!strcasecmp(status, "BUSY"))
 					res = pbx_builtin_busy(c, "10");
-				goto out;
+				error = 1; /* XXX disable message */
+				break;	/* exit from the 'for' loop */
+			}
+
+			if (collect_digits(c, waittime, dst_exten, sizeof(dst_exten), pos))
+				break;
+			if (ast_exists_extension(c, c->context, dst_exten, 1, c->cid.cid_num)) /* Prepare the next cycle */
+				set_ext_pri(c, dst_exten, 1);
+			else {
+				/* No such extension */
+				if (!ast_strlen_zero(dst_exten)) {
+					/* An invalid extension */
+					if (ast_exists_extension(c, c->context, "i", 1, c->cid.cid_num)) {
+						if (option_verbose > 2)
+							ast_verbose( VERBOSE_PREFIX_3 "Invalid extension '%s' in context '%s' on %s\n", dst_exten, c->context, c->name);
+						pbx_builtin_setvar_helper(c, "INVALID_EXTEN", dst_exten);
+						set_ext_pri(c, "i", 1);
+					} else {
+						ast_log(LOG_WARNING, "Invalid extension '%s', but no rule 'i' in context '%s'\n", dst_exten, c->context);
+						found = 1; /* XXX disable message */
+						break;
+					}
+				} else {
+					/* A simple timeout */
+					if (ast_exists_extension(c, c->context, "t", 1, c->cid.cid_num)) {
+						if (option_verbose > 2)
+							ast_verbose( VERBOSE_PREFIX_3 "Timeout on %s\n", c->name);
+						set_ext_pri(c, "t", 1);
+					} else {
+						ast_log(LOG_WARNING, "Timeout, but no rule 't' in context '%s'\n", c->context);
+						found = 1; /* XXX disable message */
+						break;
+					}
+				}
+			}
+			if (c->cdr) {
+				if (option_verbose > 2)
+					ast_verbose(VERBOSE_PREFIX_2 "CDR updated on %s\n",c->name);
+				ast_cdr_update(c);
 			}
 		}
 	}
-	if (firstpass)
+	if (!found && !error)
 		ast_log(LOG_WARNING, "Don't know what to do with '%s'\n", c->name);
-out:
 	if ((res != AST_PBX_KEEPALIVE) && ast_exists_extension(c, c->context, "h", 1, c->cid.cid_num)) {
 		if (c->cdr && ast_opt_end_cdr_before_h_exten)
 			ast_cdr_end(c->cdr);
@@ -2266,6 +2275,16 @@ static void decrease_call_count(void)
 	ast_mutex_unlock(&maxcalllock);
 }
 
+static void destroy_exten(struct ast_exten *e)
+{
+	if (e->priority == PRIORITY_HINT)
+		ast_remove_hint(e);
+
+	if (e->datad)
+		e->datad(e->data);
+	free(e);
+}
+
 static void *pbx_thread(void *data)
 {
 	/* Oh joyeous kernel, we're a new thread, with nothing to do but
@@ -2486,104 +2505,72 @@ int ast_context_remove_extension(const char *context, const char *extension, int
 int ast_context_remove_extension2(struct ast_context *con, const char *extension, int priority, const char *registrar)
 {
 	struct ast_exten *exten, *prev_exten = NULL;
+	struct ast_exten *peer;
 
 	ast_mutex_lock(&con->lock);
 
-	/* go through all extensions in context and search the right one ... */
-	exten = con->root;
-	while (exten) {
-
-		/* look for right extension */
+	/* scan the extension list to find matching extension-registrar */
+	for (exten = con->root; exten; prev_exten = exten, exten = exten->next) {
 		if (!strcmp(exten->exten, extension) &&
-			(!registrar || !strcmp(exten->registrar, registrar))) {
-			struct ast_exten *peer;
-
-			/* should we free all peers in this extension? (priority == 0)? */
-			if (priority == 0) {
-				/* remove this extension from context list */
-				if (prev_exten)
-					prev_exten->next = exten->next;
-				else
-					con->root = exten->next;
-
-				/* fire out all peers */
-				peer = exten;
-				while (peer) {
-					exten = peer->peer;
-
-					if (!peer->priority==PRIORITY_HINT)
-					    ast_remove_hint(peer);
-
-					peer->datad(peer->data);
-					free(peer);
-
-					peer = exten;
-				}
+			(!registrar || !strcmp(exten->registrar, registrar)))
+			break;
+	}
+	if (!exten) {
+		/* we can't find right extension */
+		ast_mutex_unlock(&con->lock);
+		return -1;
+	}
 
-				ast_mutex_unlock(&con->lock);
-				return 0;
-			} else {
-				/* remove only extension with exten->priority == priority */
-				struct ast_exten *previous_peer = NULL;
-
-				peer = exten;
-				while (peer) {
-					/* is this our extension? */
-					if (peer->priority == priority &&
-						(!registrar || !strcmp(peer->registrar, registrar) )) {
-						/* we are first priority extension? */
-						if (!previous_peer) {
-							/* exists previous extension here? */
-							if (prev_exten) {
-								/* yes, so we must change next pointer in
-								 * previous connection to next peer
-								 */
-								if (peer->peer) {
-									prev_exten->next = peer->peer;
-									peer->peer->next = exten->next;
-								} else
-									prev_exten->next = exten->next;
-							} else {
-								/* no previous extension, we are first
-								 * extension, so change con->root ...
-								 */
-								if (peer->peer)
-									con->root = peer->peer;
-								else
-									con->root = exten->next;
-							}
-						} else {
-							/* we are not first priority in extension */
-							previous_peer->peer = peer->peer;
-						}
+	/* should we free all peers in this extension? (priority == 0)? */
+	if (priority == 0) {
+		/* remove this extension from context list */
+		if (prev_exten)
+			prev_exten->next = exten->next;
+		else
+			con->root = exten->next;
 
-						/* now, free whole priority extension */
-						if (peer->priority==PRIORITY_HINT)
-						    ast_remove_hint(peer);
-						peer->datad(peer->data);
-						free(peer);
+		/* fire out all peers */
+		while ( (peer = exten) ) {
+			exten = peer->peer; /* prepare for next entry */
+			destroy_exten(peer);
+		}
+	} else {
+		/* scan the priority list to remove extension with exten->priority == priority */
+		struct ast_exten *previous_peer = NULL;
 
-						ast_mutex_unlock(&con->lock);
-						return 0;
-					} else {
-						/* this is not right extension, skip to next peer */
-						previous_peer = peer;
-						peer = peer->peer;
-					}
-				}
+		for (peer = exten; peer; previous_peer = peer, peer = peer->peer) {
+			if (peer->priority == priority &&
+					(!registrar || !strcmp(peer->registrar, registrar) ))
+				break; /* found our priority */
+		}
+		if (!peer) { /* not found */
+			ast_mutex_unlock(&con->lock);
+			return -1;
+		}
+		/* we are first priority extension? */
+		if (!previous_peer) {
+			/*
+			 * We are first in the priority chain, so must update the extension chain.
+			 * The next node is either the next priority or the next extension
+			 */
+			struct ast_exten *next_node = peer->peer ? peer->peer : peer->next;
 
-				ast_mutex_unlock(&con->lock);
-				return -1;
-			}
+			if (!prev_exten)	/* change the root... */
+				con->root = next_node;
+			else
+				prev_exten->next = next_node; /* unlink */
+			if (peer->peer)	/* XXX update the new head of the pri list */
+				peer->peer->next = peer->next;
+		} else { /* easy, we are not first priority in extension */
+			previous_peer->peer = peer->peer;
 		}
 
-		prev_exten = exten;
-		exten = exten->next;
+		/* now, free whole priority extension */
+		destroy_exten(peer);
+		/* XXX should we return -1 ? */
 	}
-
-	/* we can't find right extension */
 	ast_mutex_unlock(&con->lock);
-	return -1;
+	return 0;
 }
 
 
@@ -3370,13 +3357,17 @@ void ast_merge_contexts_and_delete(struct ast_context **extcontexts, const char
 
 	tmp = *extcontexts;
 	if (registrar) {
+		/* XXX remove previous contexts from same registrar */
+		ast_log(LOG_WARNING, "must remove any reg %s\n", registrar);
 		__ast_context_destroy(NULL,registrar);
 		while (tmp) {
 			lasttmp = tmp;
 			tmp = tmp->next;
 		}
 	} else {
+		/* XXX remove contexts with the same name */
 		while (tmp) {
+			ast_log(LOG_WARNING, "must remove %s  reg %s\n", tmp->name, tmp->registrar);
 			__ast_context_destroy(tmp,tmp->registrar);
 			lasttmp = tmp;
 			tmp = tmp->next;
@@ -4069,6 +4060,64 @@ static void null_datad(void *foo)
 {
 }
 
+/*! \brief add the extension in the priority chain */
+static int add_pri(struct ast_context *con, struct ast_exten *tmp,
+	struct ast_exten *el, struct ast_exten *e, int replace)
+{
+	struct ast_exten *ep;
+
+	for (ep = NULL; e ; ep = e, e = e->peer) {
+		if (e->priority >= tmp->priority)
+			break;
+	}
+	if (!e) {	/* go at the end, and ep is surely set because the list is not empty */
+		ep->peer = tmp;
+		return 0;	/* success */
+	}
+	if (e->priority == tmp->priority) {
+		/* Can't have something exactly the same.  Is this a
+		   replacement?  If so, replace, otherwise, bonk. */
+		if (!replace) {
+			ast_log(LOG_WARNING, "Unable to register extension '%s', priority %d in '%s', already in use\n", tmp->exten, tmp->priority, con->name);
+			tmp->datad(tmp->data);
+			free(tmp);
+			return -1;
+		}
+		/* we are replacing e, so copy the link fields and then update
+		 * whoever pointed to e to point to us
+		 */
+		tmp->next = e->next;	/* not meaningful if we are not first in the peer list */
+		tmp->peer = e->peer;	/* always meaningful */
+		if (ep)			/* We're in the peer list, just insert ourselves */
+			ep->peer = tmp;
+		else if (el)		/* We're the first extension. Take over e's functions */
+			el->next = tmp;
+		else			/* We're the very first extension.  */
+			con->root = tmp;
+		if (tmp->priority == PRIORITY_HINT)
+			ast_change_hint(e,tmp);
+		/* Destroy the old one */
+		e->datad(e->data);
+		free(e);
+	} else {	/* Slip ourselves in just before e */
+		tmp->peer = e;
+		tmp->next = e->next;	/* extension chain, or NULL if e is not the first extension */
+		if (ep)			/* Easy enough, we're just in the peer list */
+			ep->peer = tmp;
+		else {			/* we are the first in some peer list, so link in the ext list */
+			if (el)
+				el->next = tmp;	/* in the middle... */
+			else
+				con->root = tmp; /* ... or at the head */
+			e->next = NULL;	/* e is no more at the head, so e->next must be reset */
+		}
+		/* And immediately return success. */
+		if (tmp->priority == PRIORITY_HINT)
+			 ast_add_hint(tmp);
+	}
+	return 0;
+}
+
 /*! \brief
  * Main interface to add extensions to the list for out context.
  *
@@ -4120,7 +4169,7 @@ int ast_add_extension2(struct ast_context *con,
 	 * priorities (same extension) are kept in a list, according to the
 	 * peer pointer.
 	 */
-	struct ast_exten *tmp, *e, *el = NULL, *ep = NULL;
+	struct ast_exten *tmp, *e, *el = NULL;
 	int res;
 	int length;
 	char *p;
@@ -4197,113 +4246,21 @@ int ast_add_extension2(struct ast_context *con,
 			else
 				res = strcasecmp(e->cidmatch, tmp->cidmatch);
 		}
-		if (res == 0) {
-			/* We have an exact match, now we find where we are
-			   and be sure there's no duplicates */
-			while(e) {
-				if (e->priority == tmp->priority) {
-					/* Can't have something exactly the same.  Is this a
-					   replacement?  If so, replace, otherwise, bonk. */
-					if (replace) {
-						if (ep) {
-							/* We're in the peer list, insert ourselves */
-							ep->peer = tmp;
-							tmp->peer = e->peer;
-						} else if (el) {
-							/* We're the first extension. Take over e's functions */
-							el->next = tmp;
-							tmp->next = e->next;
-							tmp->peer = e->peer;
-						} else {
-							/* We're the very first extension.  */
-							con->root = tmp;
-							tmp->next = e->next;
-							tmp->peer = e->peer;
-						}
-						if (tmp->priority == PRIORITY_HINT)
-						    ast_change_hint(e,tmp);
-						/* Destroy the old one */
-						e->datad(e->data);
-						free(e);
-						ast_mutex_unlock(&con->lock);
-						if (tmp->priority == PRIORITY_HINT)
-						    ast_change_hint(e, tmp);
-						/* And immediately return success. */
-						LOG;
-						return 0;
-					} else {
-						ast_log(LOG_WARNING, "Unable to register extension '%s', priority %d in '%s', already in use\n", tmp->exten, tmp->priority, con->name);
-						tmp->datad(tmp->data);
-						free(tmp);
-						ast_mutex_unlock(&con->lock);
-						errno = EEXIST;
-						return -1;
-					}
-				} else if (e->priority > tmp->priority) {
-					/* Slip ourselves in just before e */
-					if (ep) {
-						/* Easy enough, we're just in the peer list */
-						ep->peer = tmp;
-						tmp->peer = e;
-					} else if (el) {
-						/* We're the first extension in this peer list */
-						el->next = tmp;
-						tmp->next = e->next;
-						e->next = NULL;
-						tmp->peer = e;
-					} else {
-						/* We're the very first extension altogether */
-						tmp->next = con->root->next;
-						/* Con->root must always exist or we couldn't get here */
-						tmp->peer = con->root;
-						con->root = tmp;
-					}
-					ast_mutex_unlock(&con->lock);
-
-					/* And immediately return success. */
-					if (tmp->priority == PRIORITY_HINT)
-						 ast_add_hint(tmp);
-
-					LOG;
-					return 0;
-				}
-				ep = e;
-				e = e->peer;
-			}
-			/* If we make it here, then it's time for us to go at the very end.
-			   ep *must* be defined or we couldn't have gotten here. */
-			ep->peer = tmp;
+		if (res >= 0)
+			break;
+	}
+	if (e && res == 0) { /* exact match, insert in the pri chain */
+			int ret = add_pri(con, tmp, el, e, replace);
 			ast_mutex_unlock(&con->lock);
-			if (tmp->priority == PRIORITY_HINT)
-				ast_add_hint(tmp);
-
-			/* And immediately return success. */
-			LOG;
-			return 0;
-
-		} else if (res > 0) {
-			/* Insert ourselves just before 'e'.  We're the first extension of
-			   this kind */
-			tmp->next = e;
-			if (el) {
-				/* We're in the list somewhere */
-				el->next = tmp;
-			} else {
-				/* We're at the top of the list */
-				con->root = tmp;
+			if (ret < 0)
+				errno = EEXIST;
+			else {
+				LOG;
 			}
-			ast_mutex_unlock(&con->lock);
-			if (tmp->priority == PRIORITY_HINT)
-				ast_add_hint(tmp);
-
-			/* And immediately return success. */
-			LOG;
-			return 0;
-		}
-
-		el = e;
+			return ret;
 	}
-	/* If we fall all the way through to here, then we need to be on the end. */
+	/* ok found the insertion place, right before 'e' (if any) */
+	tmp->next = e;
 	if (el)
 		el->next = tmp;
 	else
@@ -4723,16 +4680,6 @@ outgoing_app_cleanup:
 	return res;
 }
 
-static void destroy_exten(struct ast_exten *e)
-{
-	if (e->priority == PRIORITY_HINT)
-		ast_remove_hint(e);
-
-	if (e->datad)
-		e->datad(e->data);
-	free(e);
-}
-
 void __ast_context_destroy(struct ast_context *con, const char *registrar)
 {
 	struct ast_context *tmp, *tmpl=NULL;
@@ -4745,6 +4692,7 @@ void __ast_context_destroy(struct ast_context *con, const char *registrar)
 	for (tmp = contexts; tmp; ) {
 		struct ast_context *next;	/* next starting point */
 		for (; tmp; tmpl = tmp, tmp = tmp->next) {
+			ast_log(LOG_WARNING, "check ctx %s %s\n", tmp->name, tmp->registrar);
 			if ( (!registrar || !strcasecmp(registrar, tmp->registrar)) &&
 			     (!con || !strcasecmp(tmp->name, con->name)) )
 				break;	/* found it */
@@ -4752,6 +4700,7 @@ void __ast_context_destroy(struct ast_context *con, const char *registrar)
 		if (!tmp)	/* not found, we are done */
 			break;
 		ast_mutex_lock(&tmp->lock);
+		ast_log(LOG_WARNING, "delete ctx %s %s\n", tmp->name, tmp->registrar);
 		next = tmp->next;
 		if (tmpl)
 			tmpl->next = next;
@@ -5246,6 +5195,7 @@ void pbx_builtin_setvar_helper(struct ast_channel *chan, const char *name, const
 	struct varshead *headp;
 	const char *nametail = name;
 
+	/* XXX may need locking on the channel ? */
 	if (name[strlen(name)-1] == ')') {
 		char *function = ast_strdupa(name);