From 5d64f3660f6d2f465bb784947c2b9efe3cc084d2 Mon Sep 17 00:00:00 2001
From: Ralf Kistner <ralf@journeyapps.com>
Date: Mon, 17 Feb 2025 14:53:57 +0200
Subject: [PATCH] Add experimental include_old and include_metadata options.

---
 crates/core/src/util.rs  |  4 +++-
 crates/core/src/views.rs | 27 +++++++++++++++++++++++++--
 2 files changed, 28 insertions(+), 3 deletions(-)

diff --git a/crates/core/src/util.rs b/crates/core/src/util.rs
index 47f1d0b..8bbe7b6 100644
--- a/crates/core/src/util.rs
+++ b/crates/core/src/util.rs
@@ -54,7 +54,9 @@ pub fn extract_table_info(
         json_extract(?1, '$.name') as name,
         ifnull(json_extract(?1, '$.view_name'), json_extract(?1, '$.name')) as view_name,
         json_extract(?1, '$.local_only') as local_only,
-        json_extract(?1, '$.insert_only') as insert_only",
+        json_extract(?1, '$.insert_only') as insert_only,
+        json_extract(?1, '$.include_old') as include_old,
+        json_extract(?1, '$.include_metadata') as include_metadata",
     )?;
     statement.bind_text(1, data, sqlite::Destructor::STATIC)?;
 
diff --git a/crates/core/src/views.rs b/crates/core/src/views.rs
index d534ee2..f196be7 100644
--- a/crates/core/src/views.rs
+++ b/crates/core/src/views.rs
@@ -24,6 +24,7 @@ fn powersync_view_sql_impl(
     let name = statement.column_text(0)?;
     let view_name = statement.column_text(1)?;
     let local_only = statement.column_int(2)? != 0;
+    let include_metadata = statement.column_int(5)? != 0;
 
     let quoted_name = quote_identifier(view_name);
     let internal_name = quote_internal_name(name, local_only);
@@ -48,6 +49,11 @@ fn powersync_view_sql_impl(
         column_values.push(foo);
     }
 
+    if include_metadata {
+        column_names_quoted.push(quote_identifier("_metadata"));
+        column_values.push(String::from("NULL"));
+    }
+
     let view_statement = format!(
         "CREATE VIEW {:}({:}) AS SELECT {:} FROM {:} -- powersync-auto-generated",
         quoted_name,
@@ -206,6 +212,9 @@ fn powersync_trigger_update_sql_impl(
     let view_name = statement.column_text(1)?;
     let local_only = statement.column_int(2)? != 0;
     let insert_only = statement.column_int(3)? != 0;
+    // TODO: allow accepting a column list
+    let include_old = statement.column_type(4)? == sqlite::ColumnType::Text;
+    let include_metadata = statement.column_int(5)? != 0;
 
     let quoted_name = quote_identifier(view_name);
     let internal_name = quote_internal_name(name, local_only);
@@ -218,6 +227,20 @@ fn powersync_trigger_update_sql_impl(
     let json_fragment_new = json_object_fragment("NEW", &stmt2)?;
     stmt2.reset()?;
     let json_fragment_old = json_object_fragment("OLD", &stmt2)?;
+    let old_fragment: String;
+    let metadata_fragment: &str;
+
+    if include_old {
+        old_fragment = format!(", 'old', {:}", json_fragment_old);
+    } else {
+        old_fragment = String::from("");
+    }
+
+    if include_metadata {
+        metadata_fragment = ", 'metadata', NEW._metadata";
+    } else {
+        metadata_fragment = "";
+    }
 
     return if !local_only && !insert_only {
         let trigger = format!("\
@@ -232,10 +255,10 @@ BEGIN
   UPDATE {:}
       SET data = {:}
       WHERE id = NEW.id;
-  INSERT INTO powersync_crud_(data) VALUES(json_object('op', 'PATCH', 'type', {:}, 'id', NEW.id, 'data', json(powersync_diff({:}, {:}))));
+  INSERT INTO powersync_crud_(data) VALUES(json_object('op', 'PATCH', 'type', {:}, 'id', NEW.id, 'data', json(powersync_diff({:}, {:})){:}{:}));
   INSERT OR IGNORE INTO ps_updated_rows(row_type, row_id) VALUES({:}, NEW.id);
   INSERT OR REPLACE INTO ps_buckets(name, last_op, target_op) VALUES('$local', 0, {:});
-END", trigger_name, quoted_name, internal_name, json_fragment_new, type_string, json_fragment_old, json_fragment_new, type_string, MAX_OP_ID);
+END", trigger_name, quoted_name, internal_name, json_fragment_new, type_string, json_fragment_old, json_fragment_new, old_fragment, metadata_fragment, type_string, MAX_OP_ID);
         Ok(trigger)
     } else if local_only {
         let trigger = format!(