Add some very first parts of the network code.

Cargo.lock

@@ -53,6 +53,11 @@ name = "autocfg"
 version = "0.1.7"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 
+[[package]]
+name = "autocfg"
+version = "1.0.0"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+
 [[package]]
 name = "base64"
 version = "0.11.0"
@@ -520,6 +525,14 @@ dependencies = [
  "winapi 0.3.8 (registry+https://github.com/rust-lang/crates.io-index)",
 ]
 
+[[package]]
+name = "num-traits"
+version = "0.2.11"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+dependencies = [
+ "autocfg 1.0.0 (registry+https://github.com/rust-lang/crates.io-index)",
+]
+
 [[package]]
 name = "num_cpus"
 version = "1.12.0"
@@ -700,6 +713,25 @@ name = "regex-syntax"
 version = "0.6.14"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 
+[[package]]
+name = "rmp"
+version = "0.8.9"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+dependencies = [
+ "byteorder 1.3.2 (registry+https://github.com/rust-lang/crates.io-index)",
+ "num-traits 0.2.11 (registry+https://github.com/rust-lang/crates.io-index)",
+]
+
+[[package]]
+name = "rmp-serde"
+version = "0.14.3"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+dependencies = [
+ "byteorder 1.3.2 (registry+https://github.com/rust-lang/crates.io-index)",
+ "rmp 0.8.9 (registry+https://github.com/rust-lang/crates.io-index)",
+ "serde 1.0.104 (registry+https://github.com/rust-lang/crates.io-index)",
+]
+
 [[package]]
 name = "rust-argon2"
 version = "0.7.0"
@@ -906,6 +938,7 @@ dependencies = [
  "futures 0.3.1 (registry+https://github.com/rust-lang/crates.io-index)",
  "futures-tokio-compat 0.1.0 (git+https://github.com/mgottschlag/futures-tokio-compat.git)",
  "log 0.4.8 (registry+https://github.com/rust-lang/crates.io-index)",
+ "rmp-serde 0.14.3 (registry+https://github.com/rust-lang/crates.io-index)",
  "serde 1.0.104 (registry+https://github.com/rust-lang/crates.io-index)",
  "serde_json 1.0.45 (registry+https://github.com/rust-lang/crates.io-index)",
  "structopt 0.3.8 (registry+https://github.com/rust-lang/crates.io-index)",
@@ -1027,6 +1060,7 @@ dependencies = [
 "checksum async-tungstenite 0.3.1 (registry+https://github.com/rust-lang/crates.io-index)" = "37250bc739b253cf2d861047a7bcaad1d46d1d027070b44dbeab9168b40cf407"
 "checksum atty 0.2.14 (registry+https://github.com/rust-lang/crates.io-index)" = "d9b39be18770d11421cdb1b9947a45dd3f37e93092cbf377614828a319d5fee8"
 "checksum autocfg 0.1.7 (registry+https://github.com/rust-lang/crates.io-index)" = "1d49d90015b3c36167a20fe2810c5cd875ad504b39cff3d4eae7977e6b7c1cb2"
+"checksum autocfg 1.0.0 (registry+https://github.com/rust-lang/crates.io-index)" = "f8aac770f1885fd7e387acedd76065302551364496e46b3dd00860b2f8359b9d"
 "checksum base64 0.11.0 (registry+https://github.com/rust-lang/crates.io-index)" = "b41b7ea54a0c9d92199de89e20e58d49f02f8e699814ef3fdf266f6f748d15c7"
 "checksum bitflags 1.2.1 (registry+https://github.com/rust-lang/crates.io-index)" = "cf1de2fe8c75bc145a2f577add951f8134889b4795d47466a54a5c846d691693"
 "checksum blake2b_simd 0.5.10 (registry+https://github.com/rust-lang/crates.io-index)" = "d8fb2d74254a3a0b5cac33ac9f8ed0e44aa50378d9dbb2e5d83bd21ed1dc2c8a"
@@ -1083,6 +1117,7 @@ dependencies = [
 "checksum mio-uds 0.6.7 (registry+https://github.com/rust-lang/crates.io-index)" = "966257a94e196b11bb43aca423754d87429960a768de9414f3691d6957abf125"
 "checksum miow 0.2.1 (registry+https://github.com/rust-lang/crates.io-index)" = "8c1f2f3b1cf331de6896aabf6e9d55dca90356cc9960cca7eaaf408a355ae919"
 "checksum net2 0.2.33 (registry+https://github.com/rust-lang/crates.io-index)" = "42550d9fb7b6684a6d404d9fa7250c2eb2646df731d1c06afc06dcee9e1bcf88"
+"checksum num-traits 0.2.11 (registry+https://github.com/rust-lang/crates.io-index)" = "c62be47e61d1842b9170f0fdeec8eba98e60e90e5446449a0545e5152acd7096"
 "checksum num_cpus 1.12.0 (registry+https://github.com/rust-lang/crates.io-index)" = "46203554f085ff89c235cd12f7075f3233af9b11ed7c9e16dfe2560d03313ce6"
 "checksum opaque-debug 0.2.3 (registry+https://github.com/rust-lang/crates.io-index)" = "2839e79665f131bdb5782e51f2c6c9599c133c6098982a54c794358bf432529c"
 "checksum percent-encoding 2.1.0 (registry+https://github.com/rust-lang/crates.io-index)" = "d4fd5641d01c8f18a23da7b6fe29298ff4b55afcccdf78973b24cf3175fee32e"
@@ -1106,6 +1141,8 @@ dependencies = [
 "checksum redox_users 0.3.4 (registry+https://github.com/rust-lang/crates.io-index)" = "09b23093265f8d200fa7b4c2c76297f47e681c655f6f1285a8780d6a022f7431"
 "checksum regex 1.3.4 (registry+https://github.com/rust-lang/crates.io-index)" = "322cf97724bea3ee221b78fe25ac9c46114ebb51747ad5babd51a2fc6a8235a8"
 "checksum regex-syntax 0.6.14 (registry+https://github.com/rust-lang/crates.io-index)" = "b28dfe3fe9badec5dbf0a79a9cccad2cfc2ab5484bdb3e44cbd1ae8b3ba2be06"
+"checksum rmp 0.8.9 (registry+https://github.com/rust-lang/crates.io-index)" = "0f10b46df14cf1ee1ac7baa4d2fbc2c52c0622a4b82fa8740e37bc452ac0184f"
+"checksum rmp-serde 0.14.3 (registry+https://github.com/rust-lang/crates.io-index)" = "4c1ee98f14fe8b8e9c5ea13d25da7b2a1796169202c57a09d7288de90d56222b"
 "checksum rust-argon2 0.7.0 (registry+https://github.com/rust-lang/crates.io-index)" = "2bc8af4bda8e1ff4932523b94d3dd20ee30a87232323eda55903ffd71d2fb017"
 "checksum rustversion 1.0.2 (registry+https://github.com/rust-lang/crates.io-index)" = "b3bba175698996010c4f6dce5e7f173b6eb781fce25d2cfc45e27091ce0b79f6"
 "checksum ryu 1.0.2 (registry+https://github.com/rust-lang/crates.io-index)" = "bfa8506c1de11c9c4e4c38863ccbe02a305c8188e85a05a784c9e11e1c3910c8"

Cargo.toml

@@ -16,4 +16,5 @@ futures-tokio-compat = { git = "https://github.com/mgottschlag/futures-tokio-com
 async-tungstenite = { version = "0.3", features = ["tokio-runtime"] }
 env_logger = "0.7"
 log = "0.4"
+rmp-serde = "0.14"
 fswatcher = { git = "https://github.com/mgottschlag/fswatcher-rs.git" }

src/lib.rs

@@ -1,8 +1,12 @@
+extern crate rmp_serde as rmps;
+
 use std::io;
 
 mod database;
 mod file_system_watcher;
 mod file_tree;
+pub mod network;
+pub mod protocol;
 
 pub use database::Database;
 pub use file_system_watcher::FileSystemWatcher;

src/network/client.rs

@@ -0,0 +1,21 @@
+use futures::Future;
+use serde::de::DeserializeOwned;
+use serde::Serialize;
+
+use std::time::Duration;
+
+trait Connection {
+    type Request: Serialize;
+    type Response: DeserializeOwned; // TODO: Better lifetime for zero-copy deserialization of large amounts of data?
+    type Call: RemoteCall<Output = Self::Response>;
+
+    fn call(call: Self::Request) -> Self::Call;
+
+    // TODO: Server-client events.
+}
+
+trait RemoteCall: Future {
+    // TODO
+
+    fn with_timeout(self, timeout: Duration) -> Self;
+}

src/network/mod.rs

@@ -0,0 +1,3 @@
+mod client;
+mod packet_connection;
+mod server;

src/network/packet_connection.rs

@@ -0,0 +1,117 @@
+//! Module which implements a low-level packet protocol over websockets.
+//!
+//! The low-level protocol needs to implement two basic pieces of functionality: It needs to be
+//! able to implement remote procedure calls from the client to the server, and it needs to
+//! provide a method for the server to send asynchronous events. A protocol for both cases is
+//! outlined below, where each packet is sent as one WebSocket message.
+//!
+//! Remote procedure call:
+//! - The client allocates an ID from the range between 0..2^31-1 that is not currently in use
+//!   for another RPC in progress.
+//! - The client prepares a packet with this ID, "response = false", and the appropriate
+//!   payload and sends the packet to the server.
+//! - The server receives the packet, processes the request and sends a packet back with the
+//!   identical ID and "response = true".
+//! - In case of an error, the payload has the type "Error" which in turn contains the error
+//!   type.
+//! - Unpon reception of the response, the client is free to reuse the ID for further RPCs.
+//! Note that this protocol does not allow the client to cancel an RPC that is currently in
+//! progress - implementing such functionality is difficult, error-prone, and most likely not
+//! worth the effort.
+//!
+//! Server-side event:
+//! - The server creates a packet with the ID 2^31 and the event content and sends it to the
+//!   client.
+//! Note that the client does not have any method to acknowledge event reception. As events are
+//! asynchronous compared to RPCs on the same connection, the event type needs to be designed in
+//! a way that no such temporal information is necessary to process the events.
+//! TODO: Example to demonstrate the problem.
+
+use serde::de::DeserializeOwned;
+use serde::{Deserialize, Serialize};
+
+trait PacketConnection {
+    type Payload: Serialize + DeserializeOwned;
+
+    // TODO
+}
+
+#[derive(Clone, Debug, Deserialize, Serialize, PartialEq)]
+pub struct Packet<Payload> {
+    pub id: u32,
+    pub response: bool,
+    pub payload: Payload,
+}
+
+#[cfg(test)]
+mod tests {
+    use rmps::Serializer;
+
+    use super::*;
+    use crate::protocol::{PacketPayload, ServerInfoResponse};
+
+    /// Test whether serialization of packets matches the expected values.
+    /// TODO: TGhese tests should be in protocol.rs.
+    #[test]
+    fn test_serde_compatibility() {
+        let tests = [
+            (
+                Packet {
+                    id: 42,
+                    response: false,
+                    payload: PacketPayload::ServerInfo,
+                },
+                vec![
+                    131, 162, 105, 100, 42, 168, 114, 101, 115, 112, 111, 110, 115, 101, 194, 167,
+                    112, 97, 121, 108, 111, 97, 100, 129, 170, 83, 101, 114, 118, 101, 114, 73,
+                    110, 102, 111, 192,
+                ],
+            ),
+            (
+                Packet {
+                    id: 42,
+                    response: true,
+                    payload: PacketPayload::ServerInfoResponse(ServerInfoResponse {
+                        version: "0.1".to_owned(),
+                    }),
+                },
+                vec![
+                    131, 162, 105, 100, 42, 168, 114, 101, 115, 112, 111, 110, 115, 101, 195, 167,
+                    112, 97, 121, 108, 111, 97, 100, 129, 178, 83, 101, 114, 118, 101, 114, 73,
+                    110, 102, 111, 82, 101, 115, 112, 111, 110, 115, 101, 129, 167, 118, 101, 114,
+                    115, 105, 111, 110, 163, 48, 46, 49,
+                ],
+            ),
+            (
+                Packet {
+                    id: 42,
+                    response: true,
+                    payload: PacketPayload::Error(crate::protocol::Error::InvalidParameter),
+                },
+                vec![
+                    131, 162, 105, 100, 42, 168, 114, 101, 115, 112, 111, 110, 115, 101, 195, 167,
+                    112, 97, 121, 108, 111, 97, 100, 129, 165, 69, 114, 114, 111, 114, 129, 176,
+                    73, 110, 118, 97, 108, 105, 100, 80, 97, 114, 97, 109, 101, 116, 101, 114, 192,
+                ],
+            ),
+        ];
+
+        for test in tests.iter() {
+            let mut serialized = Vec::new();
+            test.0
+                .serialize(
+                    &mut Serializer::new(&mut serialized)
+                        .with_struct_map()
+                        .with_string_variants(),
+                )
+                .unwrap();
+            let deserialized: Packet<PacketPayload> =
+                rmps::decode::from_slice(&serialized).unwrap();
+
+            // Test that serializing produces the expected binary results.
+            assert_eq!(serialized, test.1);
+            // Test that deserializing yields the original again.
+            assert_eq!(deserialized, test.0);
+        }
+    }
+}

src/network/server.rs

@@ -0,0 +1 @@
+

src/protocol.rs

@@ -0,0 +1,138 @@
+use serde::{Deserialize, Serialize};
+
+/*pub trait Protocol {
+    fn login_password(&mut self, user: &str, password: &str) -> Result<String, Error>;
+    fn login_app_key(&mut self, user: &str, key: &str) -> Result<(), Error>;
+
+    fn register_interest(&mut self, path: &str) -> Result<(), Error>;
+    fn unregister_interest(&mut self, path: &str) -> Result<(), Error>;
+    fn get_file_update_stream() ->
+
+    fn list_directory(path: &str) -> Result<DirectoryListing, Error>;
+    fn get_file_metadata(path: &str) -> Result<FileMetadata, Error>;
+    // TODO
+}*/
+
+/*pub struct DirectoryListing {
+    own_version: u64,
+    entries: Vec<FileMetadata>,
+    // TODO
+}
+
+pub struct FileMetadata {
+    name: String,
+    version: u64,
+    size: u64,
+    type_: DirectoryEntryType,
+}
+
+pub enum DirectoryEntryType {
+    Directory,
+    File,
+    SymbolicLink,
+}*/
+
+#[derive(Clone, Debug, Deserialize, Serialize, PartialEq)]
+pub enum PacketPayload {
+    Error(Error),
+    ServerInfo,
+    ServerInfoResponse(ServerInfoResponse),
+    PasswordLogin(PasswordLogin),
+    PasswordLoginResponse(PasswordLoginResponse),
+    AppKeyLogin(AppKeyLogin),
+    AppKeyLoginResponse(AppKeyLoginResponse),
+    RegisterInterest(RegisterInterest),
+    RegisterInterestResponse(RegisterInterestResponse),
+    UnregisterInterest(UnregisterInterest),
+    UnregisterInterestResponse(UnregisterInterestResponse),
+    ListDirectory(ListDirectory),
+    ListDirectoryResponse(ListDirectoryResponse),
+    GetFileMetadata(GetFileMetadata),
+    GetFileMetadataResponse(GetFileMetadataResponse),
+    GetFileContent(GetFileContent),
+    GetFileContentResponse(GetFileContentResponse),
+    StartFileUpdate,
+    UpdateFileContent,
+    FinishFileUpdate,
+}
+
+#[derive(Clone, Debug, Deserialize, Serialize, PartialEq)]
+pub enum Error {
+    InvalidParameter,
+}
+
+#[derive(Clone, Debug, Deserialize, Serialize, PartialEq)]
+pub struct ServerInfoResponse {
+    // TODO: Version of the protocol, type of the server (encrypted/unencrypted).
+    pub version: String,
+}
+
+#[derive(Clone, Debug, Deserialize, Serialize, PartialEq)]
+pub struct PasswordLogin {
+    // TODO
+}
+
+#[derive(Clone, Debug, Deserialize, Serialize, PartialEq)]
+pub struct PasswordLoginResponse {
+    // TODO
+}
+
+#[derive(Clone, Debug, Deserialize, Serialize, PartialEq)]
+pub struct AppKeyLogin {
+    // TODO
+}
+
+#[derive(Clone, Debug, Deserialize, Serialize, PartialEq)]
+pub struct AppKeyLoginResponse {
+    // TODO
+}
+
+#[derive(Clone, Debug, Deserialize, Serialize, PartialEq)]
+pub struct RegisterInterest {
+    // TODO
+}
+
+#[derive(Clone, Debug, Deserialize, Serialize, PartialEq)]
+pub struct RegisterInterestResponse {
+    // TODO
+}
+
+#[derive(Clone, Debug, Deserialize, Serialize, PartialEq)]
+pub struct UnregisterInterest {
+    // TODO
+}
+
+#[derive(Clone, Debug, Deserialize, Serialize, PartialEq)]
+pub struct UnregisterInterestResponse {
+    // TODO
+}
+
+#[derive(Clone, Debug, Deserialize, Serialize, PartialEq)]
+pub struct ListDirectory {
+    // TODO
+}
+
+#[derive(Clone, Debug, Deserialize, Serialize, PartialEq)]
+pub struct ListDirectoryResponse {
+    // TODO
+}
+
+#[derive(Clone, Debug, Deserialize, Serialize, PartialEq)]
+pub struct GetFileMetadata {
+    // TODO
+}
+
+#[derive(Clone, Debug, Deserialize, Serialize, PartialEq)]
+pub struct GetFileMetadataResponse {
+    // TODO
+}
+
+#[derive(Clone, Debug, Deserialize, Serialize, PartialEq)]
+pub struct GetFileContent {
+    // TODO
+}
+
+#[derive(Clone, Debug, Deserialize, Serialize, PartialEq)]
+pub struct GetFileContentResponse {
+    // TODO
+}