Add support for tab-completion when selecting by rule

When selecting messages based on a previously defined rule, this patch
allows for completing the name of the rule if the enable-tab-completion
feature is set.

1 files changed, 136 insertions, 11 deletions

diff --git a/alpine/mailcmd.c b/alpine/mailcmd.c
index ed93348d..05c7de26 100644
--- a/alpine/mailcmd.c
+++ b/alpine/mailcmd.c
@@ -107,7 +107,8 @@ SEARCHSET *visible_searchset(MAILSTREAM *, MSGNO_S *);
 int	  select_by_status(MAILSTREAM *, SEARCHSET **);
 int	  select_by_rule(MAILSTREAM *, SEARCHSET **);
 int	  select_by_thread(MAILSTREAM *, MSGNO_S *, SEARCHSET **);
-char     *choose_a_rule(int);
+char     *choose_a_rule(int, char *);
+int       rulenick_complete(int, char *, int);
 int	  select_by_keyword(MAILSTREAM *, SEARCHSET **);
 char     *choose_a_keyword(void);
 int	  select_sort(struct pine *, int, SortOrder *, int *);
@@ -328,6 +329,14 @@ static ESCKEY_S sel_size_opt[] = {
     {-1, 0, NULL, NULL}
 };
 
+static ESCKEY_S sel_rule_opt[] = {
+    {0, 0, NULL, NULL},
+    {ctrl('T'), 14, "^T", N_("To List")},
+    {0, 0, NULL, NULL}, /* Reserved for TAB completion */
+    {'!', '!', "!", N_("Not")},
+    {-1, 0, NULL, NULL}
+};
+
 static ESCKEY_S sel_key_opt[] = {
     {0, 0, NULL, NULL},
     {ctrl('T'), 14, "^T", N_("To List")},
@@ -8856,7 +8865,7 @@ select_by_rule(MAILSTREAM *stream, SEARCHSET **limitsrch)
 {
     char       rulenick[1000], *nick;
     PATGRP_S  *patgrp;
-    int        r, not = 0, we_cancel = 0, rflags = ROLE_DO_SRCH
+    int        r, last_r = 0, not = 0, we_cancel = 0, rflags = ROLE_DO_SRCH
 				    | ROLE_DO_INCOLS
 				    | ROLE_DO_ROLES
 				    | ROLE_DO_SCORES
@@ -8866,6 +8875,16 @@ select_by_rule(MAILSTREAM *stream, SEARCHSET **limitsrch)
     rulenick[0] = '\0';
     ps_global->mangled_footer = 1;
 
+    if(F_ON(F_ENABLE_TAB_COMPLETE, ps_global)){
+	sel_rule_opt[2].ch    = TAB;
+	sel_rule_opt[2].rval  = 15;
+	sel_rule_opt[2].name  = "TAB";
+	sel_rule_opt[2].label = N_("Complete");
+    }
+    else{
+	memset(&sel_rule_opt[2], 0, sizeof(sel_rule_opt[2]));
+    }
+
     do{
 	int oe_flags;
 
@@ -8874,11 +8893,11 @@ select_by_rule(MAILSTREAM *stream, SEARCHSET **limitsrch)
 			     sizeof(rulenick),
 			     not ? _("Rule to NOT match: ")
 			         : _("Rule to match: "),
-			     sel_key_opt, NO_HELP, &oe_flags);
+			     sel_rule_opt, NO_HELP, &oe_flags);
 
 	if(r == 14){
 	    /* select rulenick from a list */
-	    if((nick=choose_a_rule(rflags)) != NULL){
+	    if((nick=choose_a_rule(rflags, NULL)) != NULL){
 		strncpy(rulenick, nick, sizeof(rulenick)-1);
 		rulenick[sizeof(rulenick)-1] = '\0';
 		fs_give((void **) &nick);
@@ -8886,6 +8905,23 @@ select_by_rule(MAILSTREAM *stream, SEARCHSET **limitsrch)
 	    else
 	      r = 4;
 	}
+	else if(r == 15){
+	    int n = rulenick_complete(rflags, rulenick, sizeof(rulenick));
+
+	    if(n > 1 && last_r == 15 && !(oe_flags & OE_USER_MODIFIED)){
+		/* double tab with multiple completions: select from list */
+		if((nick=choose_a_rule(rflags, rulenick)) != NULL){
+		    strncpy(rulenick, nick, sizeof(rulenick)-1);
+		    rulenick[sizeof(rulenick)-1] = '\0';
+		    fs_give((void **) &nick);
+		    r = 0;
+		}
+		else
+		    r = 4;
+	    }
+	    else if(n != 1)
+		Writechar(BELL, 0);
+	}
 	else if(r == '!')
 	  not = !not;
 
@@ -8899,8 +8935,9 @@ select_by_rule(MAILSTREAM *stream, SEARCHSET **limitsrch)
 	}
 
 	removing_leading_and_trailing_white_space(rulenick);
+	last_r = r;
 
-    }while(r == 3 || r == 4 || r == '!');
+    }while(r == 3 || r == 4 || r == 15 || r == '!');
 
 
     /*
@@ -8942,14 +8979,18 @@ select_by_rule(MAILSTREAM *stream, SEARCHSET **limitsrch)
 /*
  * Allow user to choose a rule from their list of rules.
  *
+ * Args    rflags -- Pattern types to choose from
+ *         prefix -- Only list rules matching the given prefix
+ *
  * Returns an allocated rule nickname on success, NULL otherwise.
  */
 char *
-choose_a_rule(int rflags)
+choose_a_rule(int rflags, char *prefix)
 {
     char      *choice = NULL;
     char     **rule_list, **lp;
     int        cnt = 0;
+    int        prefix_length = 0;
     PAT_S     *pat;
     PAT_STATE  pstate;
     void (*redraw)(void) = ps_global->redrawer;
@@ -8964,8 +9005,15 @@ choose_a_rule(int rflags)
      * Build a list of rules to choose from.
      */
 
-    for(pat = first_pattern(&pstate); pat; pat = next_pattern(&pstate))
-      cnt++;
+    if(prefix)
+	prefix_length = strlen(prefix);
+
+    for(pat = first_pattern(&pstate); pat; pat = next_pattern(&pstate)) {
+	if(!pat->patgrp || !pat->patgrp->nick)
+	    continue;
+	if(!prefix || strncmp(pat->patgrp->nick, prefix, prefix_length) == 0)
+	    cnt++;
+    }
 
     if(cnt <= 0){
 	q_status_message(SM_ORDER, 3, 4, _("No rules defined, use Setup/Rules"));
@@ -8975,9 +9023,12 @@ choose_a_rule(int rflags)
     lp = rule_list = (char **) fs_get((cnt + 1) * sizeof(*rule_list));
     memset(rule_list, 0, (cnt+1) * sizeof(*rule_list));
 
-    for(pat = first_pattern(&pstate); pat; pat = next_pattern(&pstate))
-      *lp++ = cpystr((pat->patgrp && pat->patgrp->nick)
-			  ? pat->patgrp->nick : "?");
+    for(pat = first_pattern(&pstate); pat; pat = next_pattern(&pstate)) {
+	if(!pat->patgrp || !pat->patgrp->nick)
+	    continue;
+	if(!prefix || strncmp(pat->patgrp->nick, prefix, prefix_length) == 0)
+	    *lp++ = cpystr(pat->patgrp->nick);
+    }
 
     /* TRANSLATORS: SELECT A RULE is a screen title
        TRANSLATORS: Print something1 using something2.
@@ -8998,6 +9049,80 @@ choose_a_rule(int rflags)
 
 
 /*
+ * Complete a partial rule name against the user's list of rules.
+ *
+ * Args    rflags    -- Pattern types to choose from
+ *         nick      -- Current rule nickname to complete
+ *         nick_size -- Maximum length of the nick array to store completion in
+ *
+ * Returns the number of valid completions, i.e.:
+ *
+ *  0 if there are no valid completions. The value of the nick argument has not
+ *    been changed.
+ *  1 if there is only a single valid completion. The value of the nick argument
+ *    has been replaced with the full text of that completion.
+ * >1 if there is more than one valid completion. The value of the nick argument
+ *    has been replaced with the longest substring common to all the appropriate
+ *    completions.
+ */
+int
+rulenick_complete(int rflags, char *nick, int nick_size)
+{
+    char      *candidate = NULL;
+    int        cnt = 0;
+    int        common_prefix_length = 0;
+    int        nick_length;
+    PAT_S     *pat;
+    PAT_STATE  pstate;
+
+    if(!(nonempty_patterns(rflags, &pstate) && first_pattern(&pstate)))
+	return 0;
+
+    nick_length = strlen(nick);
+
+    for(pat = first_pattern(&pstate); pat; pat = next_pattern(&pstate)){
+	if(!pat->patgrp || !pat->patgrp->nick)
+	    continue;
+	if(strncmp(pat->patgrp->nick, nick, nick_length) == 0){
+	    /* This is a candidate for completion. */
+	    cnt++;
+	    if(!candidate){
+		/* This is the first candidate. Keep it as a future reference to
+		 * compare against to find the longest common prefix length of
+		 * all the matches. */
+		candidate = pat->patgrp->nick;
+		common_prefix_length = strlen(pat->patgrp->nick);
+	    }
+	    else{
+		/* Find the common prefix length between the first candidate and
+		 * this one. */
+		int i;
+		for(i = 0; i < common_prefix_length; i++){
+		    if(pat->patgrp->nick[i] != candidate[i]){
+			/* In the event that we ended up in the middle of a
+			 * UTF-8 code point, backtrack to the byte before the
+			 * start of this code point. */
+			while(i > 0 && (candidate[i] & 0xC0) == 0x80)
+			    i--;
+			common_prefix_length = i;
+			break;
+		    }
+		}
+	    }
+	}
+    }
+
+    if(cnt > 0){
+	int length = MIN(nick_size, common_prefix_length);
+	strncpy(nick + nick_length, candidate + nick_length, length - nick_length);
+	nick[length] = '\0';
+    }
+
+    return cnt;
+}
+
+
+/*
  * Select by current thread.
  * Sets searched bits in mail_elts for this entire thread
  *