Get hydroflow to compile to WASM (hydro-project#329)

Tests do not work yet; I have a followup PR.

1. Turn off diagnostics for non-proc-macro crates. Diagnostics don't
   work when building for WASM. The proc-macro crates that are compiled
   at compile time still enable diagonstics because they target the
   (presumably non-WASM) host architecture where diagonstics work.

2. Use version 2 for the Cargo feature resolver. The version 1 resolver
   does not treat proc-macro edges differently from regular dependency
   edges. That is, suppose we depend on package P transitively via both
   a proc-macro edge and a regular edge, and the proc-macro edge enables
   feature X but the regular edge does not.

   With the version 1 resolver, Cargo will compile P only once with X
   enabled (assuming same host and target arch). With the v2 resolver,
   Cargo will compile P (at least) twice; once with X enabled for the
   proc-macro crate, once with P disabled.

   In our project, P = {hydroflow_datalog_core, hydroflow_lang}, X =
   diagnostics. The version 1 resolver works for non-WASM builds
   (because diagnostics compiles fine), but for WASM builds the v1
   resolver attempts to build hydroflow_datalog_core for WASM with
   diagnostics enabled (because of feature resolution).

   Note that enabling the v2 feature resolver should not change compile
   times: on non-WASM, diagnostics is always enabled so we only compile
   P once. On WASM builds, we would have compiled twice anyway (once for
   the host architecture for the proc-macro package, another for WASM).

3. Turn on only a subset of Tokio features when compiling for WASM. In
   particular, the WASM environment does not natively support threads
   and fails to compile with threading features enabled.

4. Manually enable the "js" feature for hydroflow/getrandom. See the
   comment in hydroflow/Cargo.toml.

Cargo.toml

@@ -14,6 +14,8 @@ members = [
     "variadics",
 ]
 
+resolver = "2"
+
 [profile.release]
 strip = true      # Strip symbols from the binary
 opt-level = "z"   # Optimize for size

hydroflow/Cargo.toml

@@ -63,18 +63,29 @@ serde = { version = "1", features = [ "derive" ] }
 serde_json = "1"
 slotmap = "1.0"
 static_assertions = "1.1.0"
-tokio = { version = "1.16", features = [ "full" ] }
 tokio-stream = { version = "0.1.10", features = [ "io-util" ] }
-tokio-util = { version = "0.7.4", features = [ "net", "codec" ] }
 variadics = { path = "../variadics" }
 rustc-hash = "1.1.0"
 tempfile = { version = "3.3.0", optional = true }
 
+[target.'cfg(not(target_arch = "wasm32"))'.dependencies]
+tokio = { version = "1.16", features = [ "full" ] }
+tokio-util = { version = "0.7.4", features = [ "net", "codec" ] }
+
+[target.'cfg(target_arch = "wasm32")'.dependencies]
+tokio = { version = "1.16", features = [ "rt" , "sync", "macros", "io-util", "time" ] }
+tokio-util = { version = "0.7.4", features = [ "codec" ] }
+# We depend on getrandom transitively through rand. To compile getrandom to
+# WASM, we need to enable its "js" feature. However, rand does not expose a
+# passthrough to enable "js" on getrandom. As a workaround, we enable the
+# getrandom js feature here; when the feature resolver computes the set of
+# features for getrandom (unification), it will include "js".
+getrandom = { version = "0.2.6", features = [ "js" ] }
+
 [dev-dependencies]
-chrono = { version = "0.4.20", features = [ "serde" ], default-features = false }
+chrono = { version = "0.4.20", features = [ "serde", "clock" ], default-features = false }
 clap = { version = "4.1.8", features = [ "derive" ] }
 colored = "2.0"
-criterion = { version = "0.4", features = [ "async_tokio", "html_reports" ] }
 futures = { version = "0.3" }
 itertools = "0.10.3"
 rand = "0.8.4"
@@ -84,3 +95,7 @@ trybuild = "1.0.71"
 hdrhistogram = "7"
 zipf = "7.0.0"
 core_affinity = "0.5.10"
+
+[target.'cfg(not(target_arch = "wasm32"))'.dev-dependencies]
+# Rayon (rust data-parallelism library) does not compile on WASM.
+criterion = { version = "0.4", features = [ "async_tokio", "html_reports" ] }

hydroflow/src/scheduled/net/mod.rs

@@ -1,3 +1,5 @@
+#![cfg(not(target_arch = "wasm32"))]
+
 //! This module contiains networking code.
 //!
 //! ## How Tokio interacts with Hydroflow (Mingwei 2021-12-07)

hydroflow/src/scheduled/net/network_vertex.rs

@@ -1,3 +1,5 @@
+#![cfg(not(target_arch = "wasm32"))]
+
 use std::collections::HashMap;
 
 use futures::{SinkExt, StreamExt};

hydroflow/src/util/mod.rs

@@ -1,8 +1,11 @@
 //! Helper utilities for the Hydroflow surface syntax.
 
 mod udp;
+#[cfg(not(target_arch = "wasm32"))]
 pub use udp::*;
+
 mod tcp;
+#[cfg(not(target_arch = "wasm32"))]
 pub use tcp::*;
 
 #[cfg(unix)]
@@ -106,11 +109,13 @@ pub fn ipv4_resolve(addr: &str) -> Result<SocketAddr, std::io::Error> {
     }
 }
 
+#[cfg(not(target_arch = "wasm32"))]
 pub async fn bind_udp_bytes(addr: SocketAddr) -> (UdpSink, UdpStream, SocketAddr) {
     let socket = tokio::net::UdpSocket::bind(addr).await.unwrap();
     udp_bytes(socket)
 }
 
+#[cfg(not(target_arch = "wasm32"))]
 pub async fn bind_udp_lines(addr: SocketAddr) -> (UdpLinesSink, UdpLinesStream, SocketAddr) {
     let socket = tokio::net::UdpSocket::bind(addr).await.unwrap();
     udp_lines(socket)

hydroflow/src/util/tcp.rs

@@ -1,3 +1,5 @@
+#![cfg(not(target_arch = "wasm32"))]
+
 use tokio::net::tcp::{OwnedReadHalf, OwnedWriteHalf};
 use tokio::net::TcpStream;
 use tokio_util::codec::{

hydroflow/src/util/udp.rs

@@ -1,3 +1,5 @@
+#![cfg(not(target_arch = "wasm32"))]
+
 use std::net::SocketAddr;
 
 use bytes::Bytes;

hydroflow/tests/surface_async.rs

@@ -1,3 +1,5 @@
+#![cfg(not(target_arch = "wasm32"))]
+
 //! Surface syntax tests of asynchrony and networking.
 
 use std::collections::{BTreeSet, HashSet};

hydroflow_datalog/Cargo.toml

@@ -12,4 +12,7 @@ quote = "1.0.0"
 syn = { version = "1.0.0", features = [ "parsing", "extra-traits" ] }
 proc-macro2 = "1.0.27"
 proc-macro-crate = "1.1.0"
-hydroflow_datalog_core = { path = "../hydroflow_datalog_core" }
+# Note: If we ever compile this proc macro crate to WASM (e.g., if we are
+# building on a WASM host), we may need to turn diagnostics off for WASM if
+# proc_macro2 does not support WASM at that time.
+hydroflow_datalog_core = { path = "../hydroflow_datalog_core", features = [ "diagnostics" ] }

hydroflow_datalog_core/Cargo.toml

@@ -7,7 +7,7 @@ edition = "2021"
 path = "src/lib.rs"
 
 [features]
-default = [ "diagnostics" ]
+default = []
 diagnostics = [ "hydroflow_lang/diagnostics" ]
 
 [dependencies]
@@ -17,7 +17,7 @@ syn = { version = "1.0.0", features = [ "parsing", "extra-traits" ] }
 proc-macro2 = "1.0.27"
 proc-macro-crate = "1.1.0"
 rust-sitter = "0.2.1"
-hydroflow_lang = { path = "../hydroflow_lang", default-features = false }
+hydroflow_lang = { path = "../hydroflow_lang" }
 
 [build-dependencies]
 rust-sitter-tool = "0.2.1"

hydroflow_internalmacro.d

@@ -0,0 +1,5 @@
+hydroflow_internalmacro.d: hydroflow_internalmacro/src/lib.rs
+
+hydroflow_internalmacro/src/lib.rs:
+
+# env-dep:CARGO_MANIFEST_DIR=/Users/tylerhou/code/hydroflow/hydroflow_internalmacro

hydroflow_internalmacro/Cargo.toml

@@ -10,4 +10,4 @@ proc-macro = true
 proc-macro2 = "1.0.0"
 proc-macro-crate = "1.1.0"
 quote = "1.0.0"
-syn = { version = "1.0.0", features = [ "parsing", "extra-traits" ] }
+syn = { version = "1.0.0", features = [ "parsing", "extra-traits", "full" ] }

hydroflow_lang/Cargo.toml

@@ -4,7 +4,7 @@ version = "0.1.0"
 edition = "2021"
 
 [features]
-default = [ "diagnostics" ]
+default = []
 diagnostics = []
 
 [dependencies]

hydroflow_macro/Cargo.toml

@@ -7,7 +7,10 @@ edition = "2021"
 proc-macro = true
 
 [dependencies]
-hydroflow_lang = { path = "../hydroflow_lang" }
+# Note: If we ever compile this proc macro crate to WASM (e.g., if we are
+# building on a WASM host), we may need to turn diagnostics off for WASM if
+# proc_macro2 still does not support WASM.
+hydroflow_lang = { path = "../hydroflow_lang", features = [ "diagnostics" ] }
 proc-macro2 = "1.0.0"
 proc-macro-crate = "1.1.0"
 quote = "1.0.0"