Merge 'Remove hardcoded flag usage in DBHeader for encryption' from Avinash Sajjanshetty

Previously, we just hardcoded the reserved space with encryption flag.
This patch removes that and sets the reserved space if a key was
specified during a creation of db

Reviewed-by: Jussi Saurio <jussi.saurio@gmail.com>

Closes #2706

core/storage/pager.rs

@@ -28,7 +28,7 @@ use super::btree::{btree_init_page, BTreePage};
 use super::page_cache::{CacheError, CacheResizeResult, DumbLruPageCache, PageCacheKey};
 use super::sqlite3_ondisk::begin_write_btree_page;
 use super::wal::CheckpointMode;
-use crate::storage::encryption::EncryptionKey;
+use crate::storage::encryption::{EncryptionKey, ENCRYPTION_METADATA_SIZE};
 
 /// SQLite's default maximum page count
 const DEFAULT_MAX_PAGE_COUNT: u32 = 0xfffffffe;
@@ -1690,6 +1690,11 @@ impl Pager {
                 assert_eq!(default_header.database_size.get(), 0);
                 default_header.database_size = 1.into();
 
+                // if a key is set, then we will reserve space for encryption metadata
+                if self.encryption_key.borrow().is_some() {
+                    default_header.reserved_space = ENCRYPTION_METADATA_SIZE as u8;
+                }
+
                 if let Some(size) = self.page_size.get() {
                     default_header.page_size = size;
                 }

core/storage/sqlite3_ondisk.rs

@@ -308,9 +308,6 @@ impl Default for DatabaseHeader {
             page_size: Default::default(),
             write_version: Version::Wal,
             read_version: Version::Wal,
-            #[cfg(feature = "encryption")]
-            reserved_space: 28,
-            #[cfg(not(feature = "encryption"))]
             reserved_space: 0,
             max_embed_frac: 64,
             min_embed_frac: 32,