feat(lsm): require changes to be committed before writing to persistent

storage

include/lander.h

@@ -51,6 +51,8 @@ lnm_http_step_err lander_post_paste_secure(lnm_http_conn *conn);
 
 lnm_http_step_err lander_stream_body_to_entry(lnm_http_conn *conn);
 
+lnm_http_step_err lander_commit_entry(lnm_http_conn *conn);
+
 lnm_http_step_err lander_post_redirect_body_to_attr(lnm_http_conn *conn);
 
 lnm_http_step_err lander_remove_entry(lnm_http_conn *conn);

lsm/include/lsm/store.h

@@ -159,6 +159,15 @@ lsm_error lsm_store_open_read(lsm_entry_handle **out, lsm_store *store,
 lsm_error lsm_store_open_write(lsm_entry_handle **out, lsm_store *store,
                                const lsm_str *key);
 
+/**
+ * Commit any changes to the persistent storage. Any changes, insertions or
+ * deletions that occured without a commit are reverted when the handle is
+ * closed.
+ *
+ * @param handle handle to the entry
+ */
+lsm_error lsm_entry_commit(lsm_entry_handle *handle);
+
 /**
  * Close an open entry handle.
  *

lsm/src/_include/lsm/store_internal.h

@@ -157,7 +157,8 @@ lsm_error lsm_entry_data_open_read(lsm_entry_handle *handle);
 lsm_error lsm_entry_data_open_write(lsm_entry_handle *handle);
 
 /**
- * Remove the entry's data file if present and close its handle.
+ * Remove the entry's data file if present and close its handle. Any uncommitted
+ * changes will be reverted.
  *
  * @param handle handle to the entry
  */

lsm/src/store/lsm_store_entry.c

@@ -58,31 +58,42 @@ lsm_error lsm_entry_handle_init(lsm_entry_handle **out) {
   return lsm_error_ok;
 }
 
-void lsm_entry_close(lsm_entry_handle *handle) {
-  if (handle->f != NULL) {
-    fclose(handle->f);
-  }
-
-  bool state_new = handle->states & lsm_entry_handle_state_new;
-  bool state_removed = handle->states & lsm_entry_handle_state_removed;
-  /* bool state_updated = handle->states & lsm_entry_handle_state_updated; */
+lsm_error lsm_entry_commit(lsm_entry_handle *handle) {
+  uint8_t state_new = handle->states & lsm_entry_handle_state_new;
+  uint8_t state_removed = handle->states & lsm_entry_handle_state_removed;
 
   // Clean new entry
   if (state_new && !state_removed) {
-    lsm_entry_disk_insert(handle);
-  }
-  // New entry that was removed before being written to disk; only its data file
-  // needs to be removed if present
-  else if (state_new && state_removed) {
-    lsm_entry_data_remove(handle);
-
-    lsm_entry_free(handle->wrapper->entry);
-    handle->wrapper->entry = NULL;
+    LSM_RES(lsm_entry_disk_insert(handle));
   }
   // Previously stored entry that needs to be removed; should be removed from db
   // file as well
   else if (state_removed && !state_new) {
-    lsm_entry_disk_remove(handle);
+    LSM_RES(lsm_entry_disk_remove(handle));
+
+    lsm_entry_free(handle->wrapper->entry);
+    handle->wrapper->entry = NULL;
+  }
+
+  // Reset states after committing current changes
+  handle->states = 0;
+
+  return lsm_error_ok;
+}
+
+void lsm_entry_close(lsm_entry_handle *handle) {
+  if (handle->f != NULL) {
+    fclose(handle->f);
+    handle->f = NULL;
+  }
+
+  uint8_t state_new = handle->states & lsm_entry_handle_state_new;
+  /* bool state_updated = handle->states & lsm_entry_handle_state_updated; */
+
+  // New entries create a wrapper in the trie that should be removed if not
+  // committed
+  if (state_new) {
+    lsm_entry_data_remove(handle);
 
     lsm_entry_free(handle->wrapper->entry);
     handle->wrapper->entry = NULL;
@@ -328,7 +339,6 @@ lsm_error lsm_entry_data_open_read(lsm_entry_handle *handle) {
   return lsm_error_ok;
 }
 
-
 lsm_error lsm_entry_data_remove(lsm_entry_handle *handle) {
   const lsm_entry *entry = handle->wrapper->entry;
 

src/lander/lander_steps.c

@@ -1,6 +1,7 @@
 #include <string.h>
 
 #include "lnm/http/loop.h"
+#include "lnm/log.h"
 #include "lnm/loop.h"
 
 #include "lander.h"
@@ -25,3 +26,12 @@ lnm_http_step_err lander_stream_body_to_entry(lnm_http_conn *conn) {
              ? lnm_http_step_err_done
              : lnm_http_step_err_io_needed;
 }
+
+lnm_http_step_err lander_commit_entry(lnm_http_conn *conn) {
+  lnm_http_loop_ctx *ctx = conn->ctx;
+  lander_ctx *c_ctx = ctx->c;
+
+  lsm_entry_commit(c_ctx->entry);
+
+  return lnm_http_step_err_done;
+}