1 files changed, 169 insertions, 0 deletions
diff --git a/rola-bucket/src/protocol.rs b/rola-bucket/src/protocol.rs
new file mode 100644
index 0000000..949e6d4
--- /dev/null
+++ b/rola-bucket/src/protocol.rs
@@ -0,0 +1,169 @@
+use std::path::Path;
+
+mod error;
+pub use error::*;
+
+/// Request used in [BucketTransferProtocol] or [AsyncBucketTransferProtocol]
+pub struct UploadToBucketRequest<'a, Info>
+where
+    Info: Clone + Sync + Send,
+{
+    /// Extra data to record during the transfer process
+    pub extra_info: &'a Info,
+
+    /// The relative file path in the bucket to store the uploaded file
+    pub relative_file_path_to_receive: &'a Path,
+
+    /// The absolute file path of the file to be uploaded to the remote bucket
+    pub absolute_file_path_to_upload: &'a Path,
+}
+
+/// Request used in [BucketTransferProtocol] or [AsyncBucketTransferProtocol]
+pub struct DownloadFromBucketRequest<'a, Info>
+where
+    Info: Clone + Sync + Send,
+{
+    /// Extra data to record during the transfer process
+    pub extra_info: &'a Info,
+
+    /// The relative file path in the bucket to download
+    pub relative_file_path_to_transfer: &'a Path,
+
+    /// The absolute file path to download the file to locally
+    pub absolute_file_path_to_download: &'a Path,
+}
+
+/// Request used in [BucketTransferProtocol] or [AsyncBucketTransferProtocol]
+pub struct TransferToClientRequest<'a, Info>
+where
+    Info: Clone + Sync + Send,
+{
+    /// Extra data to record during the transfer process
+    pub extra_info: &'a Info,
+
+    /// The relative file path for the client to download from the bucket
+    pub relative_file_path_to_download: &'a Path,
+
+    /// The absolute file path of the file to be transferred to the client
+    pub absolute_file_path_to_transfer: &'a Path,
+}
+
+/// Request used in [BucketTransferProtocol] or [AsyncBucketTransferProtocol]
+pub struct ReceiveFromClientRequest<'a, Info>
+where
+    Info: Clone + Sync + Send,
+{
+    /// Extra data to record during the transfer process
+    pub extra_info: &'a Info,
+
+    /// The relative file path in the bucket to store the uploaded file
+    pub relative_file_path_to_upload: &'a Path,
+
+    /// The absolute file path to download the file to locally
+    pub absolute_file_path_to_receive: &'a Path,
+}
+
+/// This trait is used to implement the specific workflow of file transfer
+pub trait BucketTransferProtocol {
+    /// Structure used to record transfer information
+    type TransferInfo: Clone + Sync + Send;
+
+    /// Upload a file to the storage bucket
+    /// The caller must ensure that this function performs the actual transfer operation
+    fn upload_to_bucket(
+        &self,
+        req: &UploadToBucketRequest<Self::TransferInfo>,
+    ) -> Result<(), BucketTransferProtocolError>;
+
+    /// Download a file from the storage bucket
+    /// The caller must ensure that after this function executes, a file (and only a file, not a directory) exists at the `path_to_save_file` path
+    fn download_from_bucket(
+        &self,
+        req: &DownloadFromBucketRequest<Self::TransferInfo>,
+    ) -> Result<(), BucketTransferProtocolError>;
+
+    /// Transfer a file to the client
+    /// The caller must ensure that this function performs the actual transfer operation
+    fn transfer_to_client(
+        &self,
+        req: &TransferToClientRequest<Self::TransferInfo>,
+    ) -> Result<(), BucketTransferProtocolError>;
+
+    /// Receive a file from the client
+    /// The caller must ensure that after this function executes, a file (and only a file, not a directory) exists at the `path_to_save_file` path
+    fn receive_from_client(
+        &self,
+        req: &ReceiveFromClientRequest<Self::TransferInfo>,
+    ) -> Result<(), BucketTransferProtocolError>;
+}
+
+/// This trait is used to implement the specific workflow of file transfer (asynchronous mode)
+pub trait AsyncBucketTransferProtocol {
+    /// Structure used to record transfer information
+    type TransferInfo: Clone + Sync + Send;
+
+    /// Asynchronously upload a file to the storage bucket
+    /// The caller must ensure that this function performs the actual transfer operation
+    fn upload_to_bucket_async(
+        &self,
+        req: &UploadToBucketRequest<Self::TransferInfo>,
+    ) -> impl Future<Output = Result<(), BucketTransferProtocolError>> + Send + Sync;
+
+    /// Asynchronously download a file from the storage bucket
+    /// The caller must ensure that after this function executes, a file (and only a file, not a directory) exists at the `path_to_save_file` path
+    fn download_from_bucket_async(
+        &self,
+        req: &DownloadFromBucketRequest<Self::TransferInfo>,
+    ) -> impl Future<Output = Result<(), BucketTransferProtocolError>> + Send + Sync;
+
+    /// Asynchronously transfer a file to the client
+    /// The caller must ensure that this function performs the actual transfer operation
+    fn transfer_to_client_async(
+        &self,
+        req: &TransferToClientRequest<Self::TransferInfo>,
+    ) -> impl Future<Output = Result<(), BucketTransferProtocolError>> + Send + Sync;
+
+    /// Asynchronously receive a file from the client
+    /// The caller must ensure that after this function executes, a file (and only a file, not a directory) exists at the `path_to_save_file` path
+    fn receive_from_client_async(
+        &self,
+        req: &ReceiveFromClientRequest<Self::TransferInfo>,
+    ) -> impl Future<Output = Result<(), BucketTransferProtocolError>> + Send + Sync;
+}
+
+/// Blanket implementation: automatically provides async versions of all
+/// `BucketTransferProtocol` methods by wrapping them in `async {}` blocks.
+impl<T: BucketTransferProtocol + Sync> AsyncBucketTransferProtocol for T
+where
+    T::TransferInfo: Sync,
+{
+    type TransferInfo = T::TransferInfo;
+
+    fn upload_to_bucket_async(
+        &self,
+        req: &UploadToBucketRequest<Self::TransferInfo>,
+    ) -> impl Future<Output = Result<(), BucketTransferProtocolError>> + Send + Sync {
+        async move { self.upload_to_bucket(req) }
+    }
+
+    fn download_from_bucket_async(
+        &self,
+        req: &DownloadFromBucketRequest<Self::TransferInfo>,
+    ) -> impl Future<Output = Result<(), BucketTransferProtocolError>> + Send + Sync {
+        async move { self.download_from_bucket(req) }
+    }
+
+    fn transfer_to_client_async(
+        &self,
+        req: &TransferToClientRequest<Self::TransferInfo>,
+    ) -> impl Future<Output = Result<(), BucketTransferProtocolError>> + Send + Sync {
+        async move { self.transfer_to_client(req) }
+    }
+
+    fn receive_from_client_async(
+        &self,
+        req: &ReceiveFromClientRequest<Self::TransferInfo>,
+    ) -> impl Future<Output = Result<(), BucketTransferProtocolError>> + Send + Sync {
+        async move { self.receive_from_client(req) }
+    }
+}