From a0c512273533c4ee72ae04baa34b9bc9e9650e66 Mon Sep 17 00:00:00 2001
From: Sebastian Hugentobler <sebastian@vanwa.ch>
Date: Wed, 26 Jun 2024 17:41:04 +0200
Subject: [PATCH] ensure the search database is attached to all connections

---
 calibre-db/src/calibre.rs | 16 ++++++++----
 calibre-db/src/search.rs  | 54 +++++++++++++++++++++++++++++----------
 2 files changed, 52 insertions(+), 18 deletions(-)

diff --git a/calibre-db/src/calibre.rs b/calibre-db/src/calibre.rs
index 94bfd11..1dd1164 100644
--- a/calibre-db/src/calibre.rs
+++ b/calibre-db/src/calibre.rs
@@ -1,15 +1,16 @@
 //! Bundle all functions together.
 
-use std::path::Path;
+use std::path::{Path, PathBuf};
 
 use r2d2::Pool;
 use r2d2_sqlite::SqliteConnectionManager;
+use tempfile::NamedTempFile;
 
 use crate::{
     data::{
         author::Author, book::Book, error::DataStoreError, pagination::SortOrder, series::Series,
     },
-    search::{self, search},
+    search::search,
 };
 
 /// Top level calibre functions, bundling all sub functions in one place and providing secure access to
@@ -17,6 +18,7 @@ use crate::{
 #[derive(Debug, Clone)]
 pub struct Calibre {
     pool: Pool<SqliteConnectionManager>,
+    search_db_path: PathBuf,
 }
 
 impl Calibre {
@@ -27,16 +29,20 @@ impl Calibre {
         let manager = SqliteConnectionManager::file(path);
         let pool = r2d2::Pool::new(manager)?;
 
-        search::attach(&pool)?;
+        let tmpfile = NamedTempFile::new()?;
+        let (_, search_db_path) = tmpfile.keep()?;
 
-        Ok(Self { pool })
+        Ok(Self {
+            pool,
+            search_db_path,
+        })
     }
 
     /// Full text search with a query.
     ///
     /// See https://www.sqlite.org/fts5.html#full_text_query_syntax for syntax.
     pub fn search(&self, query: &str) -> Result<Vec<Book>, DataStoreError> {
-        search(query, &self.pool)
+        search(query, &self.pool, &self.search_db_path)
     }
 
     /// Fetch book data from calibre, starting at `cursor`, fetching up to an amount of `limit` and
diff --git a/calibre-db/src/search.rs b/calibre-db/src/search.rs
index 0d61d51..8c6ae9a 100644
--- a/calibre-db/src/search.rs
+++ b/calibre-db/src/search.rs
@@ -5,10 +5,11 @@
 //! virtual table leveraging fts5 (https://www.sqlite.org/fts5.html). Full-text search is run on
 //! that virtual table.
 
+use std::path::Path;
+
 use r2d2::{Pool, PooledConnection};
 use r2d2_sqlite::SqliteConnectionManager;
 use rusqlite::named_params;
-use tempfile::NamedTempFile;
 
 use crate::data::{book::Book, error::DataStoreError};
 
@@ -32,28 +33,53 @@ const SEARCH_INIT_QUERY: &str = "INSERT INTO search.fts(book_id, data)
       LEFT JOIN main.series AS s ON b2s.series = s.id
     GROUP BY b.id";
 
-/// Attach the fts temporary database to the read-only calibre database.
-pub(crate) fn attach(pool: &Pool<SqliteConnectionManager>) -> Result<(), DataStoreError> {
-    let conn = pool.get()?;
-    let tmpfile = NamedTempFile::new()?;
-    let (_, path) = tmpfile.keep()?;
+/// Ensure the search database is attached to the connection and
+/// initializes the data if needed.
+fn ensure_search_db(
+    conn: &PooledConnection<SqliteConnectionManager>,
+    db_path: &Path,
+) -> Result<(), DataStoreError> {
+    let mut stmt =
+        conn.prepare("SELECT COUNT() FROM pragma_database_list WHERE name = 'search'")?;
+    let count: u64 = stmt.query_row([], |x| x.get(0))?;
+    let need_attachment = count == 0;
 
+    if need_attachment {
+        attach(conn, db_path)?;
+        init(conn)?;
+    }
+
+    Ok(())
+}
+
+/// Attach the fts temporary database to the read-only calibre database.
+fn attach(
+    conn: &PooledConnection<SqliteConnectionManager>,
+    db_path: &Path,
+) -> Result<(), DataStoreError> {
     conn.execute(
-        &format!("ATTACH DATABASE '{}' AS search", path.to_string_lossy()),
+        &format!("ATTACH DATABASE '{}' AS search", db_path.to_string_lossy()),
         [],
     )?;
-    init(&conn)?;
+    init(conn)?;
 
     Ok(())
 }
 
 /// Initialise the fts virtual table.
 fn init(conn: &PooledConnection<SqliteConnectionManager>) -> Result<(), DataStoreError> {
-    conn.execute(
-        "CREATE VIRTUAL TABLE search.fts USING fts5(book_id, data)",
-        [],
-    )?;
-    conn.execute(SEARCH_INIT_QUERY, [])?;
+    let mut stmt = conn
+        .prepare("SELECT COUNT() FROM search.sqlite_master WHERE type='table' AND name = 'fts'")?;
+    let count: u64 = stmt.query_row([], |x| x.get(0))?;
+    let need_init = count == 0;
+
+    if need_init {
+        conn.execute(
+            "CREATE VIRTUAL TABLE search.fts USING fts5(book_id, data)",
+            [],
+        )?;
+        conn.execute(SEARCH_INIT_QUERY, [])?;
+    }
 
     Ok(())
 }
@@ -62,8 +88,10 @@ fn init(conn: &PooledConnection<SqliteConnectionManager>) -> Result<(), DataStor
 pub(crate) fn search(
     query: &str,
     pool: &Pool<SqliteConnectionManager>,
+    search_db_path: &Path,
 ) -> Result<Vec<Book>, DataStoreError> {
     let conn = pool.get()?;
+    ensure_search_db(&conn, search_db_path)?;
 
     let mut stmt =
         conn.prepare("SELECT book_id FROM search.fts WHERE data MATCH (:query) ORDER BY rank")?;