Changed dir append to mirror commit DSL

Expiremental implementation. This opens up the opportunity to use the same
commit description for both commits and appends, which effectively do the same
thing.

This should lead to better code reuse.

lfs.c

@@ -676,6 +676,59 @@ static int lfs_dir_update(lfs_t *lfs, lfs_dir_t *dir,
     return err;
 }
 
+static int lfs_dir_append_(lfs_t *lfs, lfs_dir_t *dir,
+        lfs_entry_t *entry, struct lfs_region *region) {
+    // check if we fit, if top bit is set we do not and move on
+    while (true) {
+        if (dir->d.size + lfs_entry_size(entry) <= lfs->cfg->block_size) {
+            entry->off = dir->d.size - 4;
+            for (struct lfs_region *r = region; r; r = r->next) {
+                r->oldoff += entry->off;
+            }
+
+            lfs_entry_tole32(&entry->d);
+            int err = lfs_dir_commit(lfs, dir,
+                    &(struct lfs_region){
+                        LFS_FROM_MEM, entry->off, 0,
+                        {.m.data = &entry->d}, 4, region});
+            lfs_entry_fromle32(&entry->d);
+            return err;
+        }
+
+        // we need to allocate a new dir block
+        if (!(0x80000000 & dir->d.size)) {
+            lfs_dir_t olddir = *dir;
+            int err = lfs_dir_alloc(lfs, dir);
+            if (err) {
+                return err;
+            }
+
+            dir->d.tail[0] = olddir.d.tail[0];
+            dir->d.tail[1] = olddir.d.tail[1];
+            entry->off = dir->d.size - 4;
+            lfs_entry_tole32(&entry->d);
+            err = lfs_dir_commit(lfs, dir,
+                    &(struct lfs_region){
+                        LFS_FROM_MEM, entry->off, 0,
+                        {.m.data = &entry->d}, 4, region});
+            lfs_entry_fromle32(&entry->d);
+            if (err) {
+                return err;
+            }
+
+            olddir.d.size |= 0x80000000;
+            olddir.d.tail[0] = dir->pair[0];
+            olddir.d.tail[1] = dir->pair[1];
+            return lfs_dir_commit(lfs, &olddir, NULL);
+        }
+
+        int err = lfs_dir_fetch(lfs, dir, dir->d.tail);
+        if (err) {
+            return err;
+        }
+    }
+}
+
 static int lfs_dir_append(lfs_t *lfs, lfs_dir_t *dir,
         lfs_entry_t *entry, const void *data) {
     // check if we fit, if top bit is set we do not and move on
@@ -973,7 +1026,13 @@ int lfs_mkdir(lfs_t *lfs, const char *path) {
     cwd.d.tail[0] = dir.pair[0];
     cwd.d.tail[1] = dir.pair[1];
 
-    err = lfs_dir_append(lfs, &cwd, &entry, path);
+    err = lfs_dir_append_(lfs, &cwd, &entry,
+            &(struct lfs_region){
+                LFS_FROM_MEM, 0, 0,
+                {.m.data = (uint8_t*)&entry.d + 4}, sizeof(entry.d) - 4,
+            &(struct lfs_region){
+                LFS_FROM_MEM, 0, 0,
+                {.m.data = path}, entry.d.nlen}});
     if (err) {
         return err;
     }
@@ -1357,7 +1416,13 @@ int lfs_file_open(lfs_t *lfs, lfs_file_t *file,
         entry.d.nlen = strlen(path);
         entry.d.u.file.head = 0xffffffff;
         entry.d.u.file.size = 0;
-        err = lfs_dir_append(lfs, &cwd, &entry, path);
+        err = lfs_dir_append_(lfs, &cwd, &entry,
+                &(struct lfs_region){
+                    LFS_FROM_MEM, 0, 0,
+                    {.m.data = (uint8_t*)&entry.d + 4}, sizeof(entry.d) - 4,
+                &(struct lfs_region){
+                    LFS_FROM_MEM, 0, 0,
+                    {.m.data = path}, entry.d.nlen}});
         if (err) {
             return err;
         }
@@ -2017,7 +2082,13 @@ int lfs_rename(lfs_t *lfs, const char *oldpath, const char *newpath) {
             return err;
         }
     } else {
-        err = lfs_dir_append(lfs, &newcwd, &newentry, newpath);
+        err = lfs_dir_append_(lfs, &newcwd, &newentry,
+                &(struct lfs_region){
+                    LFS_FROM_MEM, 0, 0,
+                    {.m.data = (uint8_t*)&newentry.d + 4}, sizeof(newentry.d) - 4,
+                &(struct lfs_region){
+                    LFS_FROM_MEM, 0, 0,
+                    {.m.data = newpath}, newentry.d.nlen}});
         if (err) {
             return err;
         }