Replace worker-sets with red-black tree of watches

Inode number is unique now so we can store kqueue watches in key->value format
where key is an inode number.
TODO: consider import one of hash table implementations e.g. utlhash

Makefile.am

@@ -16,7 +16,6 @@ libinotify_la_SOURCES = \
     dep-list.c \
     inotify-watch.c \
     watch.c \
-    worker-sets.c \
     worker-thread.c \
     worker.c \
     controller.c

compat.h

@@ -59,6 +59,12 @@
             SLIST_NEXT(SLIST_NEXT(elm, field), field);                  \
 } while (0)
 #endif
+#ifndef RB_FOREACH_SAFE
+#define RB_FOREACH_SAFE(x, name, head, y)                               \
+        for ((x) = RB_MIN(name, head);                                  \
+            ((x) != NULL) && ((y) = name##_RB_NEXT(x), (x) != NULL);    \
+             (x) = (y))
+#endif
 #endif /* BUILD_LIBRARY */
 
 #ifndef HAVE_PTHREAD_BARRIER

inotify-watch.c

@@ -37,7 +37,6 @@
 #include "inotify-watch.h"
 #include "utils.h"
 #include "watch.h"
-#include "worker-sets.h"
 
 /**
  * Initialize kqueue watch and insert it into inotify watch`s watchlist
@@ -52,20 +51,12 @@ iwatch_ins_watch (i_watch *iw, int fd, watch_type_t type)
 {
     assert (iw != NULL);
 
-    if (worker_sets_extend (&iw->watches, 1) == -1) {
-        perror_msg ("Failed to extend worker sets");
-        return NULL;
-    }
-
     watch *w = watch_init (iw, type, fd);
 
-    if (w == NULL) {
-        return NULL;
+    if (w != NULL) {
+        ++w->refcount;
+        RB_INSERT (watch_tree, &iw->watches, w);
     }
-    ++w->refcount;
-    iw->watches.watches[iw->watches.length] = w;
-
-    ++iw->watches.length;
 
     return w;
 }
@@ -135,17 +126,10 @@ iwatch_init (worker *wrk, int fd, uint32_t flags)
     iw->inode = st.st_ino;
     iw->dev = st.st_dev;
 
-    if (worker_sets_init (&iw->watches) == -1) {
-        if (S_ISDIR (st.st_mode)) {
-            dl_free (deps);
-        }
-        free (iw);
-        return NULL;
-    }
+    RB_INIT (&iw->watches);
 
     watch *parent = iwatch_ins_watch (iw, fd, WATCH_USER);
     if (parent == NULL) {
-        worker_sets_free (&iw->watches);
         if (S_ISDIR (st.st_mode)) {
             dl_free (deps);
         }
@@ -177,7 +161,12 @@ iwatch_free (i_watch *iw)
 {
     assert (iw != NULL);
 
-    worker_sets_free (&iw->watches);
+    watch *w, *tmp;
+    RB_FOREACH_SAFE (w, watch_tree, &iw->watches, tmp) {
+        RB_REMOVE (watch_tree, &iw->watches, w);
+        watch_free (w);
+    }
+
     if (iw->deps != NULL) {
         dl_free (iw->deps);
     }
@@ -196,17 +185,8 @@ iwatch_find_watch (i_watch *iw, ino_t inode)
 {
     assert (iw != NULL);
 
-    size_t i;
-
-    for (i = 0; i < iw->watches.length; i++) {
-
-        watch *w = iw->watches.watches[i];
-        if (inode == w->inode) {
-            return w;
-        }
-    }
-
-    return NULL;
+    watch find = { .inode = inode };
+    return RB_FIND (watch_tree, &iw->watches, &find);
 }
 
 /**
@@ -262,14 +242,8 @@ iwatch_del_subwatch (i_watch *iw, const dep_item *di)
         --w->refcount;
 
         if (w->refcount == 0) {
-            size_t i;
-
-            for (i = 0; i < iw->watches.length; i++) {
-                if (di->inode == iw->watches.watches[i]->inode) {
-                    worker_sets_delete (&iw->watches, i);
-                    break;
-                }
-            }
+            RB_REMOVE (watch_tree, &iw->watches, w);
+            watch_free (w);
         }
     }
 }
@@ -290,9 +264,8 @@ iwatch_update_flags (i_watch *iw, uint32_t flags)
 
     iw->flags = flags;
 
-    size_t i;
-    for (i = 0; i < iw->watches.length; i++) {
-        watch *w = iw->watches.watches[i];
+    watch *w;
+    RB_FOREACH (w, watch_tree, &iw->watches) {
         uint32_t fflags = inotify_to_kqueue (flags,
                                              w->flags & WF_ISDIR,
                                              w->flags & WF_ISSUBWATCH);

inotify-watch.h

@@ -28,9 +28,10 @@
 
 typedef struct i_watch i_watch;
 
+#include "compat.h"
 #include "dep-list.h"
+#include "watch.h"
 #include "worker.h"
-#include "worker-sets.h"
 
 struct i_watch {
     int wd;                    /* watch descriptor */
@@ -39,7 +40,7 @@ struct i_watch {
     ino_t inode;               /* inode number of watched inode */
     dev_t dev;                 /* device number of watched inode */
     dep_list *deps;            /* dependence list of inotify watch */
-    worker_sets watches;       /* kqueue watches of inotify watch */
+    watch_tree watches;        /* kqueue watches of inotify watch */
     SLIST_ENTRY(i_watch) next; /* pointer to the next inotify watch in list */
 };
 

watch.c

@@ -68,6 +68,21 @@ _file_information (int fd, int *is_dir, ino_t *inode)
     }
 }
 
+/**
+ * Custom comparison function that can compare kqueue watch inode values
+ * through pointers passed by RB tree functions
+ *
+ * @param[in] w1 A pointer to a first kqueue watch to compare
+ * @param[in] w2 A pointer to a second kqueue watch to compare
+ * @return An -1, 0, or +1 if the first watch is considered to be respectively
+ * less than, equal to, or greater than the second one.
+ **/
+static int
+watch_cmp (watch *w1, watch *w2)
+{
+    return ((w1->inode > w2->inode) - (w1->inode < w2->inode));
+}
+
 /* struct kevent is declared slightly differently on the different BSDs.
  * This macros will help to avoid cast warnings on the supported platforms. */
 #if defined (__NetBSD__)
@@ -193,3 +208,5 @@ watch_free (watch *w)
     }
     free (w);
 }
+
+RB_GENERATE(watch_tree, watch, link, watch_cmp);

watch.h

@@ -27,7 +27,9 @@
 #include <dirent.h>    /* ino_t */
 
 typedef struct watch watch;
+typedef RB_HEAD(watch_tree, watch) watch_tree;
 
+#include "compat.h"    /* RB tree macroses */
 #include "inotify-watch.h"
 
 #define WF_ISSUBWATCH (1<<0)  /* a type of watch */
@@ -46,6 +48,7 @@ struct watch {
                                * to that watch */ 
     int fd;                   /* file descriptor of a watched entry */
     ino_t inode;              /* inode number for the watched entry */
+    RB_ENTRY(watch) link;     /* RB tree links */
 };
 
 int    watch_open (int dirfd, const char *path, uint32_t flags);
@@ -54,4 +57,6 @@ void   watch_free (watch *w);
 
 int    watch_register_event (watch *w, uint32_t fflags);
 
+RB_PROTOTYPE(watch_tree, watch, link, watch_cmp);
+
 #endif /* __WATCH_H__ */