Initial WebAssembly implementation

.gitignore

@@ -1 +1,3 @@
 /target
+/pkg/opentally.js
+/pkg/opentally_bg.wasm

Cargo.lock

@@ -36,12 +36,24 @@ dependencies = [
  "serde",
 ]
 
+[[package]]
+name = "bumpalo"
+version = "3.7.0"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "9c59e7af012c713f529e7a3ee57ce9b31ddd858d4b512923602f74608b009631"
+
 [[package]]
 name = "byteorder"
 version = "1.4.3"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "14c189c53d098945499cdfa7ecc63567cf3886b3332b312a5b4585d8d3a6a610"
 
+[[package]]
+name = "cfg-if"
+version = "0.1.10"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "4785bdd1c96b2a846b2bd7cc02e86b6b3dbf14e7e53446c4f54c92a361040822"
+
 [[package]]
 name = "cfg-if"
 version = "1.0.0"
@@ -74,13 +86,23 @@ dependencies = [
  "syn",
 ]
 
+[[package]]
+name = "console_error_panic_hook"
+version = "0.1.6"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "b8d976903543e0c48546a91908f21588a680a8c8f984df9a5d69feccb2b2a211"
+dependencies = [
+ "cfg-if 0.1.10",
+ "wasm-bindgen",
+]
+
 [[package]]
 name = "crc32fast"
 version = "1.2.1"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "81156fece84ab6a9f2afdb109ce3ae577e42b1228441eded99bd77f627953b1a"
 dependencies = [
- "cfg-if",
+ "cfg-if 1.0.0",
 ]
 
 [[package]]
@@ -111,7 +133,7 @@ version = "1.0.20"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "cd3aec53de10fe96d7d8c565eb17f2c687bb5518a2ec453b5b1252964526abe0"
 dependencies = [
- "cfg-if",
+ "cfg-if 1.0.0",
  "crc32fast",
  "libc",
  "miniz_oxide",
@@ -192,6 +214,15 @@ version = "0.2.95"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "789da6d93f1b866ffe175afc5322a4d76c038605a1c3319bb57b06967ca98a36"
 
+[[package]]
+name = "log"
+version = "0.4.14"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "51b9bbe6c47d51fc3e1a9b945965946b4c44142ab8792c50835a980d362c2710"
+dependencies = [
+ "cfg-if 1.0.0",
+]
+
 [[package]]
 name = "memchr"
 version = "2.4.0"
@@ -222,11 +253,13 @@ name = "opentally"
 version = "0.1.0"
 dependencies = [
  "clap",
+ "console_error_panic_hook",
  "csv",
  "flate2",
  "git-version",
  "num-traits",
  "rug",
+ "wasm-bindgen",
 ]
 
 [[package]]
@@ -356,6 +389,60 @@ version = "0.9.3"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "5fecdca9a5291cc2b8dcf7dc02453fee791a280f3743cb0905f8822ae463b3fe"
 
+[[package]]
+name = "wasm-bindgen"
+version = "0.2.74"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "d54ee1d4ed486f78874278e63e4069fc1ab9f6a18ca492076ffb90c5eb2997fd"
+dependencies = [
+ "cfg-if 1.0.0",
+ "wasm-bindgen-macro",
+]
+
+[[package]]
+name = "wasm-bindgen-backend"
+version = "0.2.74"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "3b33f6a0694ccfea53d94db8b2ed1c3a8a4c86dd936b13b9f0a15ec4a451b900"
+dependencies = [
+ "bumpalo",
+ "lazy_static",
+ "log",
+ "proc-macro2",
+ "quote",
+ "syn",
+ "wasm-bindgen-shared",
+]
+
+[[package]]
+name = "wasm-bindgen-macro"
+version = "0.2.74"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "088169ca61430fe1e58b8096c24975251700e7b1f6fd91cc9d59b04fb9b18bd4"
+dependencies = [
+ "quote",
+ "wasm-bindgen-macro-support",
+]
+
+[[package]]
+name = "wasm-bindgen-macro-support"
+version = "0.2.74"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "be2241542ff3d9f241f5e2cb6dd09b37efe786df8851c54957683a49f0987a97"
+dependencies = [
+ "proc-macro2",
+ "quote",
+ "syn",
+ "wasm-bindgen-backend",
+ "wasm-bindgen-shared",
+]
+
+[[package]]
+name = "wasm-bindgen-shared"
+version = "0.2.74"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "d7cff876b8f18eed75a66cf49b65e7f967cb354a7aa16003fb55dbfd25b44b4f"
+
 [[package]]
 name = "winapi"
 version = "0.3.9"

Cargo.toml

@@ -4,18 +4,27 @@ version = "0.1.0"
 authors = ["Lee Yingtong Li <runassudo@yingtongli.me>"]
 edition = "2018"
 
+[lib]
+crate-type = ["lib", "cdylib"]
+
 [dependencies]
-csv = "1.1.6"
-flate2 = "1.0"
 git-version = "0.3.4"
 num-traits = "0.2"
+wasm-bindgen = "0.2.74"
 
-[dependencies.rug]
+# Only for WebAssembly - include here for syntax highlighting
+console_error_panic_hook = "0.1.6"
+
+[target.'cfg(not(target_arch = "wasm32"))'.dependencies]
+csv = "1.1.6"
+flate2 = "1.0"
+
+[target.'cfg(not(target_arch = "wasm32"))'.dependencies.rug]
 version = "1.12"
 default-features = false
 features = ["integer", "rational", "float"]
 
-[dependencies.clap]
+[target.'cfg(not(target_arch = "wasm32"))'.dependencies.clap]
 #version = "3.0.0-beta.2" # Bug 2279
 git = "https://github.com/clap-rs/clap"
 branch = "master"

pkg/test.html

@@ -0,0 +1,49 @@
+<html>
+	<body>
+		<div id="output" style="white-space: pre-wrap;"></div>
+		
+		<script src="opentally.js"></script>
+		<script>
+			var election_data = '4 2\n\
+3 1 3 4 0\n\
+4 1 3 2 0\n\
+2 4 1 3 0\n\
+1 2 0\n\
+2 2 4 3 1 0\n\
+1 3 4 2 0\n\
+0\n\
+"Adam"\n\
+"Basil"\n\
+"Charlotte"\n\
+"Donald"\n\
+"Title"';
+			
+			console.log = function(v) {
+				document.getElementById('output').append(v);
+				document.getElementById('output').append("\n");
+			};
+			
+			var { CountStateFloat64, STVOptions, count_init_float64, count_one_stage_float64, election_from_blt_float64, make_and_print_result_float64 } = wasm_bindgen;
+			async function run() {
+				await wasm_bindgen("opentally_bg.wasm");
+				
+				let stv_opts = STVOptions.new(2, "one_round");
+				
+				let election = election_from_blt_float64(election_data);
+				let state = CountStateFloat64.new(election);
+				
+				count_init_float64(state, stv_opts);
+				make_and_print_result_float64(1, state);
+				
+				for (let stage_num = 2;; stage_num++) {
+					let is_done = count_one_stage_float64(state, stv_opts);
+					if (is_done) {
+						break;
+					}
+					make_and_print_result_float64(stage_num, state);
+				}
+			}
+			run();
+		</script>
+	</body>
+</html>

src/election.rs

@@ -19,7 +19,6 @@ use crate::logger::Logger;
 use crate::numbers::Number;
 
 use std::collections::HashMap;
-use std::io::{BufRead, Lines};
 
 pub struct Election<N> {
 	pub seats: usize,
@@ -28,9 +27,9 @@ pub struct Election<N> {
 }
 
 impl<N: Number> Election<N> {
-	pub fn from_blt<B: BufRead>(mut lines: Lines<B>) -> Self {
+	pub fn from_blt<I: Iterator<Item=String>>(mut lines: I) -> Self {
 		// Read first line
-		let line = lines.next().expect("Unexpected EOF").expect("IO Error");
+		let line = lines.next().expect("Unexpected EOF");
 		let mut bits = line.split(" ");
 		let num_candidates = bits.next().expect("Syntax Error").parse().expect("Syntax Error");
 		let seats: usize = bits.next().expect("Syntax Error").parse().expect("Syntax Error");
@@ -44,7 +43,6 @@ impl<N: Number> Election<N> {
 		
 		// Read ballots
 		for line in &mut lines {
-			let line = line.expect("IO Error");
 			if line == "0" {
 				break;
 			}
@@ -69,7 +67,7 @@ impl<N: Number> Election<N> {
 		
 		// Read candidates
 		for line in lines.take(num_candidates) {
-			let mut line = &line.expect("IO Error")[..];
+			let mut line = &line[..];
 			if line.starts_with("\"") && line.ends_with("\"") {
 				line = &line[1..line.len()-1];
 			}

src/main.rs

@@ -92,10 +92,10 @@ fn main() {
 	
 	// Create and count election according to --numbers
 	if cmd_opts.numbers == "rational" {
-		let election: Election<Rational> = Election::from_blt(lines);
+		let election: Election<Rational> = Election::from_blt(lines.map(|r| r.expect("IO Error").to_string()).into_iter());
 		count_election(election, cmd_opts);
 	} else if cmd_opts.numbers == "float64" {
-		let election: Election<NativeFloat64> = Election::from_blt(lines);
+		let election: Election<NativeFloat64> = Election::from_blt(lines.map(|r| r.expect("IO Error").to_string()).into_iter());
 		count_election(election, cmd_opts);
 	}
 }

src/numbers/mod.rs

@@ -16,15 +16,20 @@
  */
 
 mod native;
+
+#[cfg(not(target_arch = "wasm32"))]
 mod rational;
 
 use num_traits::{NumAssignRef, NumRef};
-use rug::{self, Assign};
 
 use std::cmp::Ord;
 use std::fmt;
 use std::ops;
 
+pub trait Assign<Src=Self> {
+	fn assign(&mut self, src: Src);
+}
+
 //pub trait Number: NumRef + NumAssignRef + PartialOrd + Assign + Clone + fmt::Display where for<'a> &'a Self: RefNum<&'a Self> {
 pub trait Number: NumRef + NumAssignRef + ops::Neg<Output=Self> + Ord + Assign + Clone + fmt::Display where for<'a> Self: Assign<&'a Self> {
 	fn new() -> Self;
@@ -42,4 +47,6 @@ pub trait Number: NumRef + NumAssignRef + ops::Neg<Output=Self> + Ord + Assign +
 }
 
 pub use self::native::NativeFloat64;
+
+#[cfg(not(target_arch = "wasm32"))]
 pub use self::rational::Rational;

src/numbers/native.rs

@@ -15,10 +15,9 @@
  *  along with this program.  If not, see <https://www.gnu.org/licenses/>.
  */
 
-use super::Number;
+use super::{Assign, Number};
 
 use num_traits::{Num, One, Zero};
-use rug::Assign;
 
 use std::cmp::{Ord, Ordering, PartialEq, PartialOrd};
 use std::num::ParseIntError;

src/numbers/rational.rs

@@ -15,10 +15,11 @@
  *  along with this program.  If not, see <https://www.gnu.org/licenses/>.
  */
 
-use super::Number;
+use super::{Assign, Number};
 
 use num_traits::{Num, One, Zero};
-use rug::{self, Assign, ops::Pow, rational::ParseRationalError};
+use rug::{self, ops::Pow, rational::ParseRationalError};
+use rug::Assign as RugAssign;
 
 use std::cmp::{Ord, Ordering, PartialEq, PartialOrd};
 use std::fmt;

src/stv/mod.rs

@@ -17,6 +17,9 @@
 
 #![allow(mutable_borrow_reservation_conflict)]
 
+//#[cfg(target_arch = "wasm32")]
+pub mod wasm;
+
 use crate::numbers::Number;
 use crate::election::{Candidate, CandidateState, CountCard, CountState, Parcel, Vote};
 

src/stv/wasm.rs

@@ -0,0 +1,156 @@
+/*  OpenTally: Open-source election vote counting
+ *  Copyright © 2021 Lee Yingtong Li (RunasSudo)
+ *
+ *  This program is free software: you can redistribute it and/or modify
+ *  it under the terms of the GNU Affero General Public License as published by
+ *  the Free Software Foundation, either version 3 of the License, or
+ *  (at your option) any later version.
+ *
+ *  This program is distributed in the hope that it will be useful,
+ *  but WITHOUT ANY WARRANTY; without even the implied warranty of
+ *  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ *  GNU Affero General Public License for more details.
+ *
+ *  You should have received a copy of the GNU Affero General Public License
+ *  along with this program.  If not, see <https://www.gnu.org/licenses/>.
+ */
+
+use crate::election::{Candidate, CandidateState, CountCard, CountState, CountStateOrRef, Election, StageResult};
+use crate::numbers::{NativeFloat64, Number};
+use crate::stv;
+
+extern crate console_error_panic_hook;
+
+use wasm_bindgen::prelude::wasm_bindgen;
+
+// Logging
+
+#[wasm_bindgen]
+extern "C" {
+	#[wasm_bindgen(js_namespace = console)]
+	fn log(s: &str);
+}
+macro_rules! cprintln {
+	($($t:tt)*) => (
+		#[allow(unused_unsafe)]
+		unsafe { log(&format_args!($($t)*).to_string()) }
+	)
+}
+
+// Exported functions
+
+#[wasm_bindgen]
+pub fn election_from_blt_float64(text: String) -> ElectionFloat64 {
+	// Install panic! hook
+	console_error_panic_hook::set_once();
+	
+	let election: Election<NativeFloat64> = Election::from_blt(text.lines().map(|s| s.to_string()).into_iter());
+	return ElectionFloat64(election);
+}
+
+#[wasm_bindgen]
+pub fn count_init_float64(state: &mut CountStateFloat64, opts: &STVOptions) {
+	stv::count_init(&mut state.0, &opts.0);
+}
+
+#[wasm_bindgen]
+pub fn count_one_stage_float64(state: &mut CountStateFloat64, opts: &STVOptions) -> bool {
+	return stv::count_one_stage(&mut state.0, &opts.0);
+}
+
+// Reporting
+
+fn print_candidates<'a, N: 'a + Number, I: Iterator<Item=(&'a Candidate, &'a CountCard<'a, N>)>>(candidates: I) {
+	for (candidate, count_card) in candidates {
+		if count_card.state == CandidateState::ELECTED {
+			cprintln!("- {}: {:.dps$} ({:.dps$}) - ELECTED {}", candidate.name, count_card.votes, count_card.transfers, count_card.order_elected, dps=2);
+		} else if count_card.state == CandidateState::EXCLUDED {
+			cprintln!("- {}: {:.dps$} ({:.dps$}) - Excluded {}", candidate.name, count_card.votes, count_card.transfers, -count_card.order_elected, dps=2);
+		} else {
+			cprintln!("- {}: {:.dps$} ({:.dps$})", candidate.name, count_card.votes, count_card.transfers, dps=2);
+		}
+	}
+}
+
+fn print_stage<N: Number>(stage_num: usize, result: &StageResult<N>) {
+	// Print stage details
+	match result.kind {
+		None => { cprintln!("{}. {}", stage_num, result.title); }
+		Some(kind) => { cprintln!("{}. {} {}", stage_num, kind, result.title); }
+	};
+	cprintln!("{}", result.logs.join(" "));
+	
+	let state = result.state.as_ref();
+	
+	// Print candidates
+	let candidates = state.election.candidates.iter()
+		.map(|c| (c, state.candidates.get(c).unwrap()));
+	print_candidates(candidates);
+	
+	// Print summary rows
+	cprintln!("Exhausted: {:.dps$} ({:.dps$})", state.exhausted.votes, state.exhausted.transfers, dps=2);
+	cprintln!("Loss by fraction: {:.dps$} ({:.dps$})", state.loss_fraction.votes, state.loss_fraction.transfers, dps=2);
+	
+	let mut total_vote = state.candidates.values().fold(N::zero(), |acc, cc| { acc + &cc.votes });
+	total_vote += &state.exhausted.votes;
+	total_vote += &state.loss_fraction.votes;
+	cprintln!("Total votes: {:.dps$}", total_vote, dps=2);
+	
+	cprintln!("Quota: {:.dps$}", state.quota, dps=2);
+	
+	cprintln!("");
+}
+
+#[wasm_bindgen]
+pub fn make_and_print_result_float64(stage_num: usize, state: &CountStateFloat64) {
+	let result = StageResult {
+		kind: state.0.kind,
+		title: &state.0.title,
+		logs: state.0.logger.render(),
+		state: CountStateOrRef::from(&state.0),
+	};
+	print_stage(stage_num, &result);
+}
+
+// Wrapper structs
+// Required as we cannot specify &'static in wasm-bindgen: issue #1187
+
+#[wasm_bindgen]
+pub struct CountStateFloat64(CountState<'static, NativeFloat64>);
+#[wasm_bindgen]
+impl CountStateFloat64 {
+	pub fn new(election: &ElectionFloat64) -> Self {
+		return CountStateFloat64(CountState::new(election.as_static()));
+	}
+}
+
+#[wasm_bindgen]
+pub struct ElectionFloat64(Election<NativeFloat64>);
+#[wasm_bindgen]
+impl ElectionFloat64 {
+	pub fn seats(&self) -> usize { self.0.seats }
+	
+	fn as_static(&self) -> &'static Election<NativeFloat64> {
+		// Need to have this as we cannot specify &'static in wasm-bindgen: issue #1187
+		unsafe {
+			let ptr = &self.0 as *const Election<NativeFloat64>;
+			&*ptr
+		}
+	}
+}
+
+#[wasm_bindgen]
+pub struct STVOptions(stv::STVOptions<'static>);
+#[wasm_bindgen]
+impl STVOptions {
+	pub fn new(round_votes: Option<usize>, exclusion: String) -> Self {
+		if exclusion == "one_round" {
+			return STVOptions(stv::STVOptions {
+				round_votes: round_votes,
+				exclusion: &"one_round",
+			});
+		} else {
+			panic!("Unknown --exclusion");
+		}
+	}
+}

tests/aec.rs

@@ -48,7 +48,7 @@ fn aec_tas19_rational() {
 	let lines = gz_reader.lines();
 	
 	// Read BLT
-	let election: Election<Rational> = Election::from_blt(lines);
+	let election: Election<Rational> = Election::from_blt(lines.map(|r| r.expect("IO Error").to_string()).into_iter());
 	
 	// TODO: Validate candidate names