feat: add uncommitted close which will withdrawn previous writes

Signed-off-by: Pascal Stauss <[email protected]>

lfs.c

@@ -581,6 +581,7 @@ static lfs_ssize_t lfs_file_flushedread(lfs_t *lfs, lfs_file_t *file,
 static lfs_ssize_t lfs_file_read_(lfs_t *lfs, lfs_file_t *file,
         void *buffer, lfs_size_t size);
 static int lfs_file_close_(lfs_t *lfs, lfs_file_t *file);
+static int lfs_file_uncommitted_close_(lfs_t *lfs, lfs_file_t *file);
 static lfs_soff_t lfs_file_size_(lfs_t *lfs, lfs_file_t *file);
 
 static lfs_ssize_t lfs_fs_size_(lfs_t *lfs);
@@ -3222,6 +3223,18 @@ static int lfs_file_close_(lfs_t *lfs, lfs_file_t *file) {
     return err;
 }
 
+static int lfs_file_uncommitted_close_(lfs_t *lfs, lfs_file_t *file) {
+    // remove from list of mdirs
+    lfs_mlist_remove(lfs, (struct lfs_mlist*)file);
+
+    // clean up memory
+    if (!file->cfg->buffer) {
+        lfs_free(file->cache.buffer);
+    }
+
+    return 0;
+}
+
 
 #ifndef LFS_READONLY
 static int lfs_file_relocate(lfs_t *lfs, lfs_file_t *file) {
@@ -6098,6 +6111,21 @@ int lfs_file_close(lfs_t *lfs, lfs_file_t *file) {
     return err;
 }
 
+int lfs_file_uncommitted_close(lfs_t *lfs, lfs_file_t *file) {
+    int err = LFS_LOCK(lfs->cfg);
+    if (err) {
+        return err;
+    }
+    LFS_TRACE("lfs_file_uncommitted_close(%p, %p)", (void*)lfs, (void*)file);
+    LFS_ASSERT(lfs_mlist_isopen(lfs->mlist, (struct lfs_mlist*)file));
+
+    err = lfs_file_uncommitted_close_(lfs, file);
+
+    LFS_TRACE("lfs_file_uncommitted_close -> %d", err);
+    LFS_UNLOCK(lfs->cfg);
+    return err;
+}
+
 #ifndef LFS_READONLY
 int lfs_file_sync(lfs_t *lfs, lfs_file_t *file) {
     int err = LFS_LOCK(lfs->cfg);

lfs.h

@@ -598,6 +598,15 @@ int lfs_file_opencfg(lfs_t *lfs, lfs_file_t *file,
 // Returns a negative error code on failure.
 int lfs_file_close(lfs_t *lfs, lfs_file_t *file);
 
+// Close a file
+//
+// Any pending writes are withdrawn.
+// If desired a previous sync call is necesarry to write pending writes out to the storage.
+// Releases any allocated resources.
+//
+// Returns a negative error code on failure.
+int lfs_file_uncommitted_close(lfs_t *lfs, lfs_file_t *file);
+
 // Synchronize a file on storage
 //
 // Any pending writes are written out to storage.