From 8d71923d4f498c8d2fcb22a72346e3e77a7c4a5b Mon Sep 17 00:00:00 2001
From: Lukas Fleischer <calcurse@cryptocrack.de>
Date: Thu, 1 Sep 2011 15:29:19 +0200
Subject: Add a garbage collector for note files

Now that we use hashes to identify notes, a garbage collector comes in
handy. We search for note files that aren't referenced anywhere. Such
files might come up if a note, that isn't connected with any other item,
is edited.

Huge parts of this code are very hackish due to our data structure
layout and the way our hash table implementation works.

Signed-off-by: Lukas Fleischer <calcurse@cryptocrack.de>
---
 src/note.c | 113 +++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 113 insertions(+)

(limited to 'src/note.c')

diff --git a/src/note.c b/src/note.c
index db5c45a..2fd022a 100644
--- a/src/note.c
+++ b/src/note.c
@@ -35,10 +35,17 @@
  */
 
 #include <unistd.h>
+#include <dirent.h>
 
 #include "calcurse.h"
 #include "sha1.h"
 
+struct note_gc_hash {
+  char *hash;
+  char buf[MAX_NOTESIZ + 1];
+  HTABLE_ENTRY (note_gc_hash);
+};
+
 /* Edit a note with an external editor. */
 void
 edit_note (char **note, char *editor)
@@ -120,3 +127,109 @@ note_read (char *buffer, FILE *fp)
   while (getc (fp) != ' ');
   buffer[MAX_NOTESIZ] = '\0';
 }
+
+static void
+note_gc_extract_key (struct note_gc_hash *data, char **key, int *len)
+{
+  *key = data->hash;
+  *len = strlen (data->hash);
+}
+
+static int
+note_gc_cmp (struct note_gc_hash *a, struct note_gc_hash *b)
+{
+  return strcmp (a->hash, b->hash);
+}
+
+/* Spot and unlink unused note files. */
+void
+note_gc (void)
+{
+  HTABLE_HEAD (htp, NOTE_GC_HSIZE, note_gc_hash) gc_htable =
+      HTABLE_INITIALIZER (&gc_htable);
+  struct note_gc_hash *hp;
+  DIR *dirp;
+  struct dirent *dp;
+  llist_item_t *i;
+  struct note_gc_hash tmph;
+  char notepath[BUFSIZ];
+
+  if (!(dirp = opendir (path_notes)))
+    return;
+
+  /* Insert all note file names into a hash table. */
+  HTABLE_GENERATE (htp, note_gc_hash, note_gc_extract_key, note_gc_cmp);
+  do
+    {
+      if ((dp = readdir (dirp)) && *(dp->d_name) != '.')
+        {
+          hp = mem_malloc (sizeof (struct note_gc_hash));
+
+          strncpy (hp->buf, dp->d_name, MAX_NOTESIZ + 1);
+          hp->hash = hp->buf;
+
+          HTABLE_INSERT (htp, &gc_htable, hp);
+        }
+    }
+  while (dp);
+
+  closedir (dirp);
+
+  /* Remove hashes that are actually in use. */
+  LLIST_TS_FOREACH (&alist_p, i)
+    {
+      struct apoint *apt = LLIST_GET_DATA (i);
+      if (apt->note)
+        {
+          tmph.hash = apt->note;
+          free (HTABLE_REMOVE (htp, &gc_htable, &tmph));
+        }
+    }
+
+  LLIST_FOREACH (&eventlist, i)
+    {
+      struct event *ev = LLIST_GET_DATA (i);
+      if (ev->note)
+        {
+          tmph.hash = ev->note;
+          free (HTABLE_REMOVE (htp, &gc_htable, &tmph));
+        }
+    }
+
+  LLIST_TS_FOREACH (&recur_alist_p, i)
+    {
+      struct recur_apoint *rapt = LLIST_GET_DATA (i);
+      if (rapt->note)
+        {
+          tmph.hash = rapt->note;
+          free (HTABLE_REMOVE (htp, &gc_htable, &tmph));
+        }
+    }
+
+  LLIST_FOREACH (&recur_elist, i)
+    {
+      struct recur_event *rev = LLIST_GET_DATA (i);
+      if (rev->note)
+        {
+          tmph.hash = rev->note;
+          free (HTABLE_REMOVE (htp, &gc_htable, &tmph));
+        }
+    }
+
+  LLIST_FOREACH (&todolist, i)
+    {
+      struct todo *todo = LLIST_GET_DATA (i);
+      if (todo->note)
+        {
+          tmph.hash = todo->note;
+          free (HTABLE_REMOVE (htp, &gc_htable, &tmph));
+        }
+    }
+
+  /* Unlink unused note files. */
+  HTABLE_FOREACH (hp, htp, &gc_htable)
+    {
+      snprintf (notepath, BUFSIZ, "%s%s", path_notes, hp->hash);
+      unlink (notepath);
+    }
+}
-- 
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