1 files changed, 48 insertions, 0 deletions
diff --git a/third_party/rust/webext-storage/src/ffi.rs b/third_party/rust/webext-storage/src/ffi.rs
new file mode 100644
index 0000000000..8816462f84
--- /dev/null
+++ b/third_party/rust/webext-storage/src/ffi.rs
@@ -0,0 +1,48 @@
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+/// This module contains glue for the FFI, including error codes and a
+/// `From<Error>` implementation for `ffi_support::ExternError`. These must be
+/// implemented in this crate, and not `webext_storage_ffi`, because of Rust's
+/// orphan rule for implementing traits (`webext_storage_ffi` can't implement
+/// a trait in `ffi_support` for a type in `webext_storage`).
+use ffi_support::{ErrorCode, ExternError};
+
+use crate::error::{Error, QuotaReason};
+
+mod error_codes {
+    /// An unexpected error occurred which likely cannot be meaningfully handled
+    /// by the application.
+    pub const UNEXPECTED: i32 = 1;
+
+    /// The application passed an invalid JSON string for a storage key or value.
+    pub const INVALID_JSON: i32 = 2;
+
+    /// The total number of bytes stored in the database for this extension,
+    /// counting all key-value pairs serialized to JSON, exceeds the allowed limit.
+    pub const QUOTA_TOTAL_BYTES_EXCEEDED: i32 = 32;
+
+    /// A single key-value pair exceeds the allowed byte limit when serialized
+    /// to JSON.
+    pub const QUOTA_ITEM_BYTES_EXCEEDED: i32 = 32 + 1;
+
+    /// The total number of key-value pairs stored for this extension exceeded the
+    /// allowed limit.
+    pub const QUOTA_MAX_ITEMS_EXCEEDED: i32 = 32 + 2;
+}
+
+impl From<Error> for ExternError {
+    fn from(err: Error) -> ExternError {
+        let code = ErrorCode::new(match &err {
+            Error::JsonError(_) => error_codes::INVALID_JSON,
+            Error::QuotaError(reason) => match reason {
+                QuotaReason::ItemBytes => error_codes::QUOTA_ITEM_BYTES_EXCEEDED,
+                QuotaReason::MaxItems => error_codes::QUOTA_MAX_ITEMS_EXCEEDED,
+                QuotaReason::TotalBytes => error_codes::QUOTA_TOTAL_BYTES_EXCEEDED,
+            },
+            _ => error_codes::UNEXPECTED,
+        });
+        ExternError::new_error(code, err.to_string())
+    }
+}