Add $history_remove_dups option to remove dups from history ring.

When set, duplicate entries will be removed from the history ring when
a new entry is added.  The duplicate removal rearranges the history
ring such that created empty slots are right after the "last" position
in the ring, preserving the most history.

Rewrite the next/prev functions to take into account that blank slots can
now be in the middle of the array.

diff --git a/doc/manual.xml.head b/doc/manual.xml.head
index d8c0f8f8a0f07fff716bcf171cb376522309fe56..9e0601490d5d8afe14db05b41ba0940f45be7b5f 100644 (file)
--- a/doc/manual.xml.head
+++ b/doc/manual.xml.head
@@ -610,9 +610,11 @@ following categories:
 
 <para>
 Mutt automatically filters out consecutively repeated items from the
-history. It also mimics the behavior of some shells by ignoring items
-starting with a space. The latter feature can be useful in macros to not
-clobber the history's valuable entries with unwanted entries.
+history.  If <link linkend="history-remove-dups">$history_remove_dups</link>
+is set, all repeated items are removed from the history.  It also mimics the
+behavior of some shells by ignoring items starting with a space. The latter
+feature can be useful in macros to not clobber the history's valuable entries
+with unwanted entries.
 </para>
 
 </sect2>

diff --git a/history.c b/history.c
index e72e9fb233fbe419f4e68958e27f4afabaa89c40..054fc54bc328c257c86362cf8ed67ad596d0c6ce 100644 (file)
--- a/history.c
+++ b/history.c
@@ -23,6 +23,44 @@
 #include "mutt.h"
 #include "history.h"
 
+/* This history ring grows from 0..HistSize, with last marking the
+ * where new entries go:
+ *         0        the oldest entry in the ring
+ *         1        entry
+ *         ...
+ *         x-1      most recently entered text
+ *  last-> x        NULL  (this will be overwritten next)
+ *         x+1      NULL
+ *         ...
+ *         HistSize NULL
+ *
+ * Once the array fills up, it is used as a ring.  last points where a new
+ * entry will go.  Older entries are "up", and wrap around:
+ *         0        entry
+ *         1        entry
+ *         ...
+ *         y-1      most recently entered text
+ *  last-> y        entry (this will be overwritten next)
+ *         y+1      the oldest entry in the ring
+ *         ...
+ *         HistSize entry
+ *
+ * When $history_remove_dups is set, duplicate entries are scanned and removed
+ * each time a new entry is added.  In order to preserve the history ring size,
+ * entries 0..last are compacted up.  Entries last+1..HistSize are
+ * compacted down:
+ *         0        entry
+ *         1        entry
+ *         ...
+ *         z-1      most recently entered text
+ *  last-> z        entry (this will be overwritten next)
+ *         z+1      NULL
+ *         z+2      NULL
+ *         ...
+ *                  the oldest entry in the ring
+ *                  next oldest entry
+ *         HistSize entry
+ */
 struct history
 {
   char **hist;
@@ -206,6 +244,51 @@ static void save_history (history_class_t hclass, const char *s)
   }
 }
 
+/* When removing dups, we want the created "blanks" to be right below the
+ * resulting h->last position.  See the comment section above 'struct history'.
+ */
+static void remove_history_dups (history_class_t hclass, const char *s)
+{
+  int source, dest, old_last;
+  struct history *h = GET_HISTORY(hclass);
+
+  if (!HistSize || !h)
+    return; /* disabled */
+
+  /* Remove dups from 0..last-1 compacting up. */
+  source = dest = 0;
+  while (source < h->last)
+  {
+    if (!mutt_strcmp (h->hist[source], s))
+      FREE (&h->hist[source++]);
+    else
+      h->hist[dest++] = h->hist[source++];
+  }
+
+  /* Move 'last' entry up. */
+  h->hist[dest] = h->hist[source];
+  old_last = h->last;
+  h->last = dest;
+
+  /* Fill in moved entries with NULL */
+  while (source > h->last)
+    h->hist[source--] = NULL;
+
+  /* Remove dups from last+1 .. HistSize compacting down. */
+  source = dest = HistSize;
+  while (source > old_last)
+  {
+    if (!mutt_strcmp (h->hist[source], s))
+      FREE (&h->hist[source--]);
+    else
+      h->hist[dest--] = h->hist[source--];
+  }
+
+  /* Fill in moved entries with NULL */
+  while (dest > old_last)
+    h->hist[dest--] = NULL;
+}
+
 void mutt_init_history(void)
 {
   history_class_t hclass;
@@ -238,6 +321,8 @@ void mutt_history_add (history_class_t hclass, const char *s, int save)
      */
     if (*s != ' ' && (!h->hist[prev] || mutt_strcmp (h->hist[prev], s) != 0))
     {
+      if (option (OPTHISTREMOVEDUPS))
+        remove_history_dups (hclass, s);
       if (save && SaveHist)
         save_history (hclass, s);
       mutt_str_replace (&h->hist[h->last++], s);
@@ -256,13 +341,17 @@ char *mutt_history_next (history_class_t hclass)
   if (!HistSize || !h)
     return (""); /* disabled */
 
-  next = h->cur + 1;
-  if (next > HistSize)
-    next = 0;
-  if (h->hist[next] || (next == h->last))
-    h->cur = next;
-  else
-    h->cur = 0;
+  next = h->cur;
+  do
+  {
+    next++;
+    if (next > HistSize)
+      next = 0;
+    if (next == h->last)
+      break;
+  } while (h->hist[next] == NULL);
+
+  h->cur = next;
   return (h->hist[h->cur] ? h->hist[h->cur] : "");
 }
 
@@ -274,15 +363,17 @@ char *mutt_history_prev (history_class_t hclass)
   if (!HistSize || !h)
     return (""); /* disabled */
 
-  prev = h->cur - 1;
-  if (prev < 0)
+  prev = h->cur;
+  do
   {
-    prev = HistSize;
-    while ((prev > 0) && (prev != h->last) && (h->hist[prev] == NULL))
-      prev--;
-  }
-  if (h->hist[prev] || (prev == h->last))
-    h->cur = prev;
+    prev--;
+    if (prev < 0)
+      prev = HistSize;
+    if (prev == h->last)
+      break;
+  } while (h->hist[prev] == NULL);
+
+  h->cur = prev;
   return (h->hist[h->cur] ? h->hist[h->cur] : "");
 }
 

diff --git a/init.h b/init.h
index f5ec7a732dfdfde24f829e03ebc458007ae4a5e7..113b98d27dfec92533a4ae6dbbe1c30fa2c8e780 100644 (file)
--- a/init.h
+++ b/init.h
@@ -1084,6 +1084,12 @@ struct option_t MuttVars[] = {
   ** .pp
   ** The file in which Mutt will save its history.
   */
+  { "history_remove_dups", DT_BOOL, R_NONE, OPTHISTREMOVEDUPS, 0 },
+  /*
+  ** .pp
+  ** When \fIset\fP, all of the string history will be scanned for duplicates
+  ** when a new entry is added.
+  */
   { "honor_disposition", DT_BOOL, R_NONE, OPTHONORDISP, 0 },
   /*
   ** .pp

diff --git a/mutt.h b/mutt.h
index d19c0c13233ce4f8c86fc17e18cbb6a3b31b1aad..b60414b348febabd037c3749a5c5cac1cf2f440e 100644 (file)
--- a/mutt.h
+++ b/mutt.h
@@ -374,6 +374,7 @@ enum
   OPTHIDETHREADSUBJECT,
   OPTHIDETOPLIMITED,
   OPTHIDETOPMISSING,
+  OPTHISTREMOVEDUPS,
   OPTHONORDISP,
   OPTIGNORELWS,
   OPTIGNORELISTREPLYTO,