net: Split read-only and read-write IndexedDB operations into separate enums (#37575)

This change allows the compiler to recognize if any read-only operations
are missing an implementation when processing a readonly transaction.

Testing: The existing behaviour is unchanged, so current tests suffice.
The new code is unused and cannot be tested.
Fixes: part of #6963

---------

Signed-off-by: Josh Matthews <josh@joshmatthews.net>

components/shared/net/indexeddb_thread.rs

@@ -67,15 +67,20 @@ impl IndexedDBKeyRange {
     }
 }
 
-// Operations that are not executed instantly, but rather added to a
-// queue that is eventually run.
 #[derive(Debug, Deserialize, Serialize)]
-pub enum AsyncOperation {
+pub enum AsyncReadOnlyOperation {
     /// Gets the value associated with the given key in the associated idb data
     GetItem(
         IndexedDBKeyType, // Key
     ),
 
+    Count(
+        IndexedDBKeyType, // Key
+    ),
+}
+
+#[derive(Debug, Deserialize, Serialize)]
+pub enum AsyncReadWriteOperation {
     /// Sets the value of the given key in the associated idb data
     PutItem(
         IndexedDBKeyType, // Key
@@ -87,15 +92,19 @@ pub enum AsyncOperation {
     RemoveItem(
         IndexedDBKeyType, // Key
     ),
+}
 
-    Count(
-        IndexedDBKeyType, // Key
-    ),
+/// Operations that are not executed instantly, but rather added to a
+/// queue that is eventually run.
+#[derive(Debug, Deserialize, Serialize)]
+pub enum AsyncOperation {
+    ReadOnly(AsyncReadOnlyOperation),
+    ReadWrite(AsyncReadWriteOperation),
 }
 
 #[derive(Debug, Deserialize, Serialize)]
 pub enum SyncOperation {
-    // Upgrades the version of the database
+    /// Upgrades the version of the database
     UpgradeVersion(
         IpcSender<Result<u64, ()>>,
         ImmutableOrigin,
@@ -103,7 +112,7 @@ pub enum SyncOperation {
         u64,    // Serial number for the transaction
         u64,    // Version to upgrade to
     ),
-    // Checks if an object store has a key generator, used in e.g. Put
+    /// Checks if an object store has a key generator, used in e.g. Put
     HasKeyGenerator(
         IpcSender<bool>,
         ImmutableOrigin,
@@ -111,7 +120,7 @@ pub enum SyncOperation {
         String, // Store
     ),
 
-    // Commits changes of a transaction to the database
+    /// Commits changes of a transaction to the database
     Commit(
         IpcSender<Result<(), ()>>,
         ImmutableOrigin,
@@ -119,7 +128,7 @@ pub enum SyncOperation {
         u64,    // Transaction serial number
     ),
 
-    // Creates a new store for the database
+    /// Creates a new store for the database
     CreateObjectStore(
         IpcSender<Result<(), ()>>,
         ImmutableOrigin,
@@ -148,23 +157,23 @@ pub enum SyncOperation {
         Option<u64>, // Eventual version
     ),
 
-    // Deletes the database
+    /// Deletes the database
     DeleteDatabase(
         IpcSender<Result<(), ()>>,
         ImmutableOrigin,
         String, // Database
     ),
 
-    // Returns an unique identifier that is used to be able to
-    // commit/abort transactions.
+    /// Returns an unique identifier that is used to be able to
+    /// commit/abort transactions.
     RegisterNewTxn(
         IpcSender<u64>,
         ImmutableOrigin,
         String, // Database
     ),
 
-    // Starts executing the requests of a transaction
-    // https://www.w3.org/TR/IndexedDB-2/#transaction-start
+    /// Starts executing the requests of a transaction
+    /// <https://www.w3.org/TR/IndexedDB-2/#transaction-start>
     StartTransaction(
         IpcSender<Result<(), ()>>,
         ImmutableOrigin,
@@ -172,7 +181,7 @@ pub enum SyncOperation {
         u64,    // The serial number of the mutating transaction
     ),
 
-    // Returns the version of the database
+    /// Returns the version of the database
     Version(
         IpcSender<u64>,
         ImmutableOrigin,