From 2f58d1ee489d25730272b940c680f5a63c9343bd Mon Sep 17 00:00:00 2001
From: Jef Roosens <roosensjef@gmail.com>
Date: Thu, 9 Nov 2023 21:32:39 +0100
Subject: [PATCH] feat(lsm): track entry idx file offset

---
 lsm/src/_include/lsm/store_internal.h |  1 +
 lsm/src/store/lsm_store_disk_read.c   |  4 ++++
 lsm/src/store/lsm_store_disk_write.c  | 22 ++++++++++++----------
 lsm/src/trie/lsm_trie.c               |  7 -------
 4 files changed, 17 insertions(+), 17 deletions(-)

diff --git a/lsm/src/_include/lsm/store_internal.h b/lsm/src/_include/lsm/store_internal.h
index e4bbdba..6bd7b00 100644
--- a/lsm/src/_include/lsm/store_internal.h
+++ b/lsm/src/_include/lsm/store_internal.h
@@ -31,6 +31,7 @@ typedef struct lsm_entry {
     lsm_attr *items;
   } attrs;
   uint64_t data_len;
+  uint64_t idx_file_offset;
 } lsm_entry;
 
 /**
diff --git a/lsm/src/store/lsm_store_disk_read.c b/lsm/src/store/lsm_store_disk_read.c
index fc4d748..17b91d7 100644
--- a/lsm/src/store/lsm_store_disk_read.c
+++ b/lsm/src/store/lsm_store_disk_read.c
@@ -150,6 +150,8 @@ lsm_error lsm_store_load_db(lsm_store *store) {
                     store->idx_file, sizeof(uint64_t), 1));
 
   for (uint64_t i = 0; i < store->idx_file_block_count; i++) {
+    uint64_t idx_file_offset = store->idx_file_size;
+
     LSM_RES(lsm_entry_read_str(&key, &store->idx_file_size, store->idx_file));
     LSM_RES(lsm_fread(&db_dim, &store->idx_file_size, store->idx_file,
                       sizeof(uint64_t), 2));
@@ -163,6 +165,8 @@ lsm_error lsm_store_load_db(lsm_store *store) {
     LSM_RES(lsm_fread(&handle->wrapper->entry->data_len, NULL, store->db_file,
                       sizeof(uint64_t), 1));
     LSM_RES(lsm_entry_read_attrs(NULL, handle, store->db_file));
+
+    handle->wrapper->entry->idx_file_offset = idx_file_offset;
     lsm_entry_close(handle);
 
     store->db_file_size += db_dim[1];
diff --git a/lsm/src/store/lsm_store_disk_write.c b/lsm/src/store/lsm_store_disk_write.c
index b79a78b..3482f53 100644
--- a/lsm/src/store/lsm_store_disk_write.c
+++ b/lsm/src/store/lsm_store_disk_write.c
@@ -41,7 +41,7 @@ static lsm_error lsm_fseek(FILE *f, uint64_t pos) {
   return lsm_error_ok;
 }
 
-lsm_error lsm_entry_write_db(uint64_t *size, FILE *db_file, lsm_entry *entry,
+lsm_error lsm_write_db_entry(uint64_t *size, FILE *db_file, lsm_entry *entry,
                              uint64_t pos) {
   *size = 0;
 
@@ -59,7 +59,7 @@ lsm_error lsm_entry_write_db(uint64_t *size, FILE *db_file, lsm_entry *entry,
   return lsm_error_ok;
 }
 
-lsm_error lsm_entry_write_idx(uint64_t *size, FILE *idx_file, lsm_entry *entry,
+lsm_error lsm_write_idx_entry(uint64_t *size, FILE *idx_file, lsm_entry *entry,
                               uint64_t offset, uint64_t len, uint64_t pos) {
   *size = 0;
 
@@ -75,27 +75,27 @@ lsm_error lsm_entry_write_idx(uint64_t *size, FILE *idx_file, lsm_entry *entry,
 lsm_error lsm_entry_sync(lsm_store *store, lsm_entry_handle *handle) {
   pthread_mutex_lock(&store->db_lock);
 
+  uint64_t db_entry_index = store->db_file_size;
+
   uint64_t db_entry_size;
   lsm_error res =
-      lsm_entry_write_db(&db_entry_size, store->db_file, handle->wrapper->entry,
+      lsm_write_db_entry(&db_entry_size, store->db_file, handle->wrapper->entry,
                          store->db_file_size);
   fflush(store->db_file);
 
-  if (res != lsm_error_ok) {
-    pthread_mutex_unlock(&store->db_lock);
+  pthread_mutex_unlock(&store->db_lock);
 
+  if (res != lsm_error_ok) {
     return res;
   }
 
-  uint64_t db_entry_index = store->db_file_size;
-
-  pthread_mutex_unlock(&store->db_lock);
-
   // Append entry to index file
   pthread_mutex_lock(&store->idx_lock);
 
+  uint64_t idx_entry_index = store->idx_file_size;
+
   uint64_t idx_entry_size;
-  res = lsm_entry_write_idx(&idx_entry_size, store->idx_file,
+  res = lsm_write_idx_entry(&idx_entry_size, store->idx_file,
                             handle->wrapper->entry, db_entry_index,
                             db_entry_size, store->idx_file_size);
 
@@ -115,6 +115,8 @@ lsm_error lsm_entry_sync(lsm_store *store, lsm_entry_handle *handle) {
       store->idx_file_size += idx_entry_size;
       store->idx_file_block_count = new_block_count;
       store->db_file_size += db_entry_size;
+
+      handle->wrapper->entry->idx_file_offset = idx_entry_index;
     }
   }
 
diff --git a/lsm/src/trie/lsm_trie.c b/lsm/src/trie/lsm_trie.c
index 8744b4e..0e5b548 100644
--- a/lsm/src/trie/lsm_trie.c
+++ b/lsm/src/trie/lsm_trie.c
@@ -252,19 +252,12 @@ lsm_error lsm_trie_remove(void **data, lsm_trie *trie, lsm_str *key) {
     return lsm_error_not_found;
   }
 
-  // Child is the node we wish to delete
   if (data != NULL) {
     *data = child->data;
   }
 
   child->data = NULL;
 
-  // We only remove child if it has no children of its own
-  if (lsm_bt_size(&child->bt) == 0) {
-    lsm_bt_remove(NULL, &parent->bt, c);
-    lsm_trie_node_free(child);
-  }
-
   trie->size--;
 
   return lsm_error_ok;