New pinning in data storage.

data.c

@@ -1347,6 +1347,56 @@ int is_muted(snac *snac, const char *actor)
 }
 
 
+/** pinning **/
+
+xs_str *_pinned_fn(snac *user, const char *id)
+{
+    xs *md5 = xs_md5_hex(id, strlen(id));
+    return xs_fmt("%s/pinned/%s", user->basedir, md5);
+}
+
+
+int is_pinned(snac *user, const char *id)
+/* returns true if this note is pinned */
+{
+    xs *fn = _pinned_fn(user, id);
+    return !!(mtime(fn) != 0.0);
+}
+
+
+int pin(snac *user, const char *id)
+/* pins a message */
+{
+    int ret = 0;
+
+    if (xs_startswith(id, user->actor)) {
+        /* create the subfolder, if it does not exist */
+        xs *fn = xs_fmt("%s/pinned/", user->basedir);
+        mkdirx(fn);
+
+        object_user_cache_add(user, id, "pinned");
+
+        ret = 1;
+    }
+
+    return ret;
+}
+
+
+void unpin(snac *user, const char *id)
+/* unpin a message */
+{
+    object_user_cache_del(user, id, "pinned");
+}
+
+
+xs_list *pinned_list(snac *user)
+/* return the lists of pinned posts */
+{
+    return object_user_cache_list(user, "pinned", XS_ALL);
+}
+
+
 xs_str *_hidden_fn(snac *snac, const char *id)
 {
     xs *md5 = xs_md5_hex(id, strlen(id));

snac.h

@@ -126,6 +126,11 @@ void mute(snac *snac, const char *actor);
 void unmute(snac *snac, const char *actor);
 int is_muted(snac *snac, const char *actor);
 
+int pin(snac *user, const char *id);
+void unpin(snac *user, const char *id);
+int is_pinned(snac *user, const char *id);
+xs_list *pinned_list(snac *user);
+
 void hide(snac *snac, const char *id);
 int is_hidden(snac *snac, const char *id);