feat(lsm): possibly added reading db file on load

lsm/example/test.c

@@ -10,7 +10,7 @@ int main() {
   lsm_str_init_copy(&data_dir, "data");
 
   lsm_store *store;
-  lsm_store_load(&store, data_dir);
+  assert(lsm_store_load(&store, data_dir) == lsm_error_ok);
 
   lsm_str *key;
   lsm_str_init_copy(&key, "key");
@@ -18,6 +18,10 @@ int main() {
   lsm_entry_handle *handle;
   assert(lsm_store_insert(&handle, store, key) == lsm_error_ok);
   
+  lsm_str *attr;
+  lsm_str_init_copy(&attr, "some attribute value");
+  lsm_entry_attr_insert(handle, lsm_attr_type_content_type, attr);
+
   lsm_str *data;
   lsm_str_init_copy(&data, "hello");
 

lsm/src/_include/lsm/store_internal.h

@@ -73,10 +73,13 @@ lsm_error lsm_entry_handle_init(lsm_entry_handle **out);
 struct lsm_store {
   lsm_trie *trie;
   lsm_str *data_path;
+
   FILE *db_file;
   uint64_t db_file_size;
   pthread_mutex_t db_lock;
+
   FILE *idx_file;
+  uint64_t idx_file_block_count;
   uint64_t idx_file_size;
   pthread_mutex_t idx_lock;
 };

lsm/src/store/lsm_store.c

@@ -63,14 +63,24 @@ lsm_error lsm_store_load(lsm_store **ptr, lsm_str *data_path) {
     if (idx_file == NULL) {
       return lsm_error_failed_io;
     }
+
+    // The database code expects the idx file to start with how many blocks it
+    // contains, so we write that here
+    uint64_t num = 0;
+
+    if (fwrite(&num, sizeof(uint64_t), 1, idx_file) == 0) {
+      return lsm_error_failed_io;
     }
 
-  LSM_RES(lsm_store_load_db(store));
+    fflush(idx_file);
+  }
 
   store->data_path = data_path;
   store->db_file = db_file;
   store->idx_file = idx_file;
 
+  LSM_RES(lsm_store_load_db(store));
+
   *ptr = store;
 
   return lsm_error_ok;

lsm/src/store/lsm_store_sync.c

@@ -1,5 +1,9 @@
-#include "lsm/store_internal.h"
+#include <stdint.h>
 #include <stdio.h>
+#include <stdlib.h>
+
+#include "lsm/store.h"
+#include "lsm/store_internal.h"
 
 static lsm_error lsm_entry_write_uint64_t(FILE *f, uint64_t num) {
   size_t res = fwrite(&num, sizeof(uint64_t), 1, f);
@@ -37,8 +41,6 @@ lsm_error lsm_entry_write_db(uint64_t *size, FILE *db_file, lsm_entry *entry) {
     *size += 2 * sizeof(uint64_t) + lsm_str_len(entry->attrs.items[i].str) * sizeof(char);
   }
 
-  printf("db size: %lu\n", *size);
-
   return lsm_error_ok;
 }
 
@@ -57,7 +59,7 @@ lsm_error lsm_entry_sync(lsm_store *store, lsm_entry_handle *handle) {
   pthread_mutex_lock(&store->db_lock);
 
   // Append entry to end of database file
-  if (fseek(store->db_file, SEEK_SET, store->db_file_size) != 0) {
+  if (fseek(store->db_file, store->db_file_size, SEEK_SET) != 0) {
     pthread_mutex_unlock(&store->db_lock);
 
     return lsm_error_failed_io;
@@ -83,34 +85,142 @@ lsm_error lsm_entry_sync(lsm_store *store, lsm_entry_handle *handle) {
   // Append entry to index file
   pthread_mutex_lock(&store->idx_lock);
 
-  if (fseek(store->idx_file, SEEK_SET, store->idx_file_size) != 0) {
+  if (fseek(store->idx_file, store->idx_file_size, SEEK_SET) != 0) {
+    printf("failed seek, %lu\n", store->idx_file_size);
     pthread_mutex_unlock(&store->idx_lock);
 
     return lsm_error_failed_io;
   }
 
   res = lsm_entry_write_idx(&entry_size, store->idx_file, handle->wrapper->entry, entry_index, entry_size);
-  fflush(store->idx_file);
 
   if (res == lsm_error_ok) {
-    store->idx_file_size += entry_size;
+    // Update the counter at the beginning of the file
+    uint64_t new_block_count = store->idx_file_block_count + 1;
+
+    if (fseek(store->idx_file, 0, SEEK_SET) != 0) {
+      pthread_mutex_unlock(&store->idx_lock);
+
+      return lsm_error_failed_io;
     }
 
+    size_t r = fwrite(&new_block_count, sizeof(uint64_t), 1, store->idx_file);
+
+    if (r != lsm_error_ok) {
+      printf("wuck\n");
+      pthread_mutex_unlock(&store->idx_lock);
+
+      return res;
+    }
+
+    store->idx_file_size += entry_size;
+    store->idx_file_block_count = new_block_count;
+  } else {
+    printf("failed write\n");
+  }
+
+  fflush(store->idx_file);
+
   pthread_mutex_unlock(&store->idx_lock);
 
   return res;
 }
 
+static lsm_error lsm_entry_read_attrs(lsm_entry_handle *handle, FILE *db_file) {
+  uint64_t attr_count;
+  size_t res = fread(&attr_count, sizeof(uint64_t), 1, db_file);
+
+  if (res == 0) {
+    return lsm_error_failed_io;
+  }
+
+  // attr_type, val_len
+  uint64_t nums[2];
+  lsm_str *val;
+
+  for (uint64_t i = 0; i < attr_count; i++) {
+    res = fread(nums, sizeof(uint64_t), 2, db_file);
+
+    if (res < 2) {
+      return lsm_error_failed_io;
+    }
+
+    char *val_s = malloc(nums[1] + 1);
+    val_s[nums[1]] = '\0';
+
+    if (val_s == NULL) {
+      return lsm_error_failed_alloc;
+    }
+    
+    uint64_t read = 0;
+
+    while (read < nums[1]) {
+      read += fread(&val_s[read], 1, nums[1] - read, db_file);
+    }
+
+    LSM_RES(lsm_str_init(&val, val_s));;
+    lsm_entry_attr_insert(handle, nums[0], val);
+  }
+
+  return lsm_error_ok;
+}
+
 lsm_error lsm_store_load_db(lsm_store *store) {
   uint64_t key_len;
-  size_t res;
+  uint64_t db_dim[2];
   lsm_str *key;
+  lsm_entry_handle *handle;
 
-  while (feof(store->idx_file) > 0) {
+  // idx file starts with block count
+  size_t res = fread(&store->idx_file_block_count, sizeof(uint64_t), 1, store->idx_file);
+
+  if (res == 0) {
+    return lsm_error_failed_io;
+  }
+
+  store->idx_file_size += sizeof(uint64_t);
+
+  for (uint64_t i = 0; i < store->idx_file_block_count; i++) {
+    // Read in idx metadata
     res = fread(&key_len, sizeof(uint64_t), 1, store->idx_file);
 
     if (res == 0) {
       return lsm_error_failed_io;
     }
+
+    char *key_s = malloc(key_len + 1);
+    key_s[key_len] = '\0';
+
+    if (key_s == NULL) {
+      return lsm_error_failed_alloc;
     }
+
+    res = fread(key_s, 1, key_len, store->idx_file);
+
+    if (res < key_len) {
+      return lsm_error_failed_io;
+    }
+
+    res = fread(db_dim, sizeof(uint64_t), 2, store->idx_file);
+
+    if (res < 2) {
+      return lsm_error_failed_io;
+    }
+
+    LSM_RES(lsm_str_init(&key, key_s));
+    LSM_RES(lsm_store_insert(&handle, store, key));
+
+    // Read attributes from database file
+    if (fseek(store->db_file, db_dim[0], SEEK_SET) != 0) {
+      return lsm_error_failed_io;
+    }
+
+    LSM_RES(lsm_entry_read_attrs(handle, store->db_file));
+    lsm_entry_close(handle);
+
+    store->idx_file_size += 3 * sizeof(uint64_t) + key_len;
+    store->db_file_size += db_dim[1];
+  }
+
+  return lsm_error_ok;
 }