From 452366b0abbae346b2beec761c910b72f3dd2fd6 Mon Sep 17 00:00:00 2001
From: Justin Worthe <justin@worthe-it.co.za>
Date: Thu, 28 Dec 2017 23:06:19 +0200
Subject: Updated WASM build to use the new wasm32-unknown-unknown target

It's only in the nightly compiler at the moment.
---
 Cargo.toml            |  2 +-
 Makefile              | 11 +++-----
 src/emscripten_api.rs | 26 ++++++++++++++++++
 src/lib.rs            | 12 ++++-----
 src/main.rs           |  6 ++---
 web/index.html        | 75 ++++++++++++++++++++++++++-------------------------
 web/main.js           | 72 +++++++++++++++++++++++++++++++++++++++++--------
 7 files changed, 139 insertions(+), 65 deletions(-)

diff --git a/Cargo.toml b/Cargo.toml
index f448215..680a811 100644
--- a/Cargo.toml
+++ b/Cargo.toml
@@ -6,7 +6,7 @@ authors = ["Justin Worthe <justin.worthe@gmail.com>"]
 [dependencies]
 bencher = "0.1.2"
 
-[target.'cfg(not(target_os = "emscripten"))'.dependencies]
+[target.'cfg(not(target_arch = "wasm32"))'.dependencies]
 portaudio = "0.7.0"
 gtk = "0.3.0"
 cairo-rs = "0.3.0"
diff --git a/Makefile b/Makefile
index 0f0d7e2..229494b 100644
--- a/Makefile
+++ b/Makefile
@@ -1,20 +1,17 @@
 all: build
 
 build-web:
-	cargo build --target=wasm32-unknown-emscripten --release
+	cargo +nightly build --target=wasm32-unknown-unknown --release
 	mkdir -p target/site
-	cp target/wasm32-unknown-emscripten/release/rusty_microphone.js target/site/
-	cp target/wasm32-unknown-emscripten/release/deps/*.wasm target/site/
+	cp target/wasm32-unknown-unknown/release/*.wasm target/site/
 	cp web/* target/site/
 
 build-web-debug:
-	cargo build --target=wasm32-unknown-emscripten
+	cargo +nightly build --target=wasm32-unknown-unknown
 	mkdir -p target/site
-	cp target/wasm32-unknown-emscripten/debug/rusty_microphone.js target/site/
-	cp target/wasm32-unknown-emscripten/debug/deps/*.wasm target/site/
+	cp target/wasm32-unknown-unknown/debug/*.wasm target/site/
 	cp web/* target/site/
 
-
 build-desktop:
 	cargo build --release
 
diff --git a/src/emscripten_api.rs b/src/emscripten_api.rs
index e296818..c7f980f 100644
--- a/src/emscripten_api.rs
+++ b/src/emscripten_api.rs
@@ -3,10 +3,36 @@ use signal::Signal;
 use pitch::Pitch;
 
 use std::os::raw::c_char;
+use std::os::raw::c_void;
+use std::mem;
 use std::ffi::CString;
 use std::slice;
 use std::f32;
 
+#[no_mangle]
+pub extern "C" fn malloc(size: usize) -> *mut c_void {
+    let mut buf = Vec::with_capacity(size);
+    let ptr = buf.as_mut_ptr();
+    mem::forget(buf);
+    return ptr as *mut c_void;
+}
+
+#[no_mangle]
+pub extern "C" fn free(ptr: *mut c_void, cap: usize) {
+    unsafe  {
+        // after it's in scope, it can go out of scope in the normal
+        // RAII cleanup.
+        let _buf = Vec::from_raw_parts(ptr, 0, cap);
+    }
+}
+
+#[no_mangle]
+pub extern "C" fn free_str(ptr: *mut c_char) {
+    unsafe {
+        let _ = CString::from_raw(ptr);
+    }
+}
+
 #[no_mangle]
 pub extern "C" fn find_fundamental_frequency(signal_ptr: *const f32, signal_length: isize, sample_rate: f32) -> f32 {
     let signal_slice = unsafe {
diff --git a/src/lib.rs b/src/lib.rs
index c2b73d1..f778f3b 100644
--- a/src/lib.rs
+++ b/src/lib.rs
@@ -3,18 +3,18 @@ pub mod signal;
 pub mod correlation;
 pub mod pitch;
 
-#[cfg(not(target_os = "emscripten"))]
+#[cfg(not(target_arch = "wasm32"))]
 extern crate gtk;
-#[cfg(not(target_os = "emscripten"))]
+#[cfg(not(target_arch = "wasm32"))]
 extern crate cairo;
-#[cfg(not(target_os = "emscripten"))]
+#[cfg(not(target_arch = "wasm32"))]
 pub mod gui;
 
-#[cfg(not(target_os = "emscripten"))]
+#[cfg(not(target_arch = "wasm32"))]
 extern crate portaudio;
-#[cfg(not(target_os = "emscripten"))]
+#[cfg(not(target_arch = "wasm32"))]
 pub mod audio;
 
-#[cfg(target_os = "emscripten")]
+#[cfg(target_arch = "wasm32")]
 pub mod emscripten_api;
 
diff --git a/src/main.rs b/src/main.rs
index cfc5629..a05c2f7 100644
--- a/src/main.rs
+++ b/src/main.rs
@@ -1,6 +1,6 @@
 extern crate rusty_microphone;
 
-#[cfg(not(target_os = "emscripten"))]
+#[cfg(not(target_arch = "wasm32"))]
 fn main() {
     use rusty_microphone::*;
 
@@ -11,7 +11,7 @@ fn main() {
     }
 }
 
-#[cfg(target_os = "emscripten")]
+#[cfg(target_arch = "wasm32")]
 fn main() {
-    println!("Hello Emscripten");
+    println!("Hello Wasm");
 }
diff --git a/web/index.html b/web/index.html
index d3f6a4b..2d957cc 100644
--- a/web/index.html
+++ b/web/index.html
@@ -1,47 +1,48 @@
+<!DOCTYPE html>
 <html>
   <head>
+    <meta charset="utf-8" />
     <link rel="stylesheet" href="style.css">
-    </head>
-    <body>
-      <h1>Rusty Microphone</h1>
-      <div id="loading">
-        Loading...
-      </div>
-      <div id="browser-support-error" class="error" style="display:none;">
-        <p>
-          It looks like something has gone wrong while loading. The
-          most likely reason for this is that this app doesn't support
-          your web browser.
-        </p>
+  </head>
+  <body>
+    <h1>Rusty Microphone</h1>
+    <div id="loading">
+      Loading...
+    </div>
+    <div id="browser-support-error" class="error" style="display:none;">
+      <p>
+        It looks like something has gone wrong while loading. The
+        most likely reason for this is that this app doesn't support
+        your web browser.
+      </p>
 
-        <p>
-          I test with the latest version of Firefox, but it should
-          also work with recent versions of Chrome, Microsoft Edge,
-          Safari and Opera. If you're running one of these browsers,
-          please make sure you've updated to the latest version.
-        </p>
+      <p>
+        I test with the latest version of Firefox, but it should
+        also work with recent versions of Chrome, Microsoft Edge,
+        Safari and Opera. If you're running one of these browsers,
+        please make sure you've updated to the latest version.
+      </p>
+    </div>
+    <div id="unexpected-error" class="error" style="display:none;">
+      <p>
+        An unexpected error has occurred. Please try again later.
+      </p>
+    </div>
+    <div id="rusty-microphone" style="display:none;">
+      <p>The current note being played is <span id="pitch-label">unknown</span></p>
+      <div id="pitch-indicator-bar-container">
+        <div id="pitch-indicator-bar"></div>
       </div>
-      <div id="unexpected-error" class="error" style="display:none;">
-        <p>
-          An unexpected error has occurred. Please try again later.
-        </p>
+      <div id="pitch-indicator-colours">
+        <div id="flat-indicator"></div>
+        <div id="sharp-indicator"></div>
       </div>
-      <div id="rusty-microphone" style="display:none;">
-        <p>The current note being played is <span id="pitch-label">unknown</span></p>
-        <div id="pitch-indicator-bar-container">
-          <div id="pitch-indicator-bar"></div>
-        </div>
-        <div id="pitch-indicator-colours">
-          <div id="flat-indicator"></div>
-          <div id="sharp-indicator"></div>
-        </div>
 
-        <canvas id="oscilloscope" width="320" height="300"></canvas>
+      <canvas id="oscilloscope" width="320" height="300"></canvas>
 
-        <p>The current framerate is <span id="frame-rate">0</span>FPS</p>
-      </div>
+      <p>The current framerate is <span id="frame-rate">0</span>FPS</p>
+    </div>
 
-      <script src="main.js"></script>
-      <script src="rusty_microphone.js"></script>
-    </body>
+    <script src="main.js"></script>
+  </body>
 </html>
diff --git a/web/main.js b/web/main.js
index 02e94fc..8d7fa33 100644
--- a/web/main.js
+++ b/web/main.js
@@ -5,7 +5,30 @@ var Module = {
     onRuntimeInitialized: main,
     onAbort: onAbort
 };
-checkBrowserSupport();
+
+var env = {
+    log2f: Math.log2,
+    roundf: Math.round
+};
+checkBrowserSupport(function() {
+    fetch('rusty_microphone.wasm')
+        .then(response => response.arrayBuffer())
+        .then(bytes => WebAssembly.instantiate(bytes, { env:env }))
+        .then(results => {
+            var mod = results.instance;
+            Module._find_fundamental_frequency = mod.exports.find_fundamental_frequency;
+            Module._hz_to_pitch = mod.exports.hz_to_pitch;
+            Module._hz_to_cents_error = mod.exports.hz_to_cents_error;
+            Module._correlation = mod.exports.correlation;
+
+            Module.memory = mod.exports.memory;
+            Module._malloc = mod.exports.malloc;
+            Module._free = mod.exports.free;
+            Module._free_str = mod.exports.free_str;
+
+            Module.onRuntimeInitialized();
+        });
+});
 
 function onAbort(reason) {
     document.getElementById('loading').setAttribute('style', 'display:none');
@@ -24,11 +47,14 @@ function supportsUserMedia() {
         typeof AudioContext === "function";
 }
 
-function checkBrowserSupport() {    
+function checkBrowserSupport(supportedCallback) {
     if (!supportsWasm() || !supportsUserMedia()) {
         document.getElementById('loading').setAttribute('style', 'display:none');
         document.getElementById('browser-support-error').removeAttribute('style');
-    }    
+    }
+    else {
+        supportedCallback();
+    }
 }
 
 /**
@@ -49,7 +75,7 @@ function jsArrayToF32ArrayPtr(jsArray, callback) {
     var nDataBytes = data.length * data.BYTES_PER_ELEMENT;
     var dataPtr = Module._malloc(nDataBytes);
 
-    var dataHeap = new Uint8Array(Module.HEAPU8.buffer, dataPtr, nDataBytes);
+    var dataHeap = new Uint8Array(Module.memory.buffer, dataPtr, nDataBytes);
     dataHeap.set(new Uint8Array(data.buffer));
 
     var result = callback(dataPtr, jsArray.length);
@@ -79,12 +105,12 @@ function jsArrayToF32ArrayPtrMutateInPlace(jsArray, mutate) {
     var nDataBytes = data.length * data.BYTES_PER_ELEMENT;
     var dataPtr = Module._malloc(nDataBytes);
 
-    var dataHeap = new Uint8Array(Module.HEAPU8.buffer, dataPtr, nDataBytes);
+    var dataHeap = new Uint8Array(Module.memory.buffer, dataPtr, nDataBytes);
     dataHeap.set(new Uint8Array(data.buffer));
 
     mutate(dataPtr, jsArray.length);
 
-    var mutatedData = new Float32Array(Module.HEAPU8.buffer, dataPtr, jsArray.length);
+    var mutatedData = new Float32Array(Module.memory.buffer, dataPtr, jsArray.length);
     var result = Array.prototype.slice.call(mutatedData);
     
     Module._free(dataPtr);
@@ -112,21 +138,45 @@ function findFundamentalFrequencyNoFree(data, samplingRate) {
     if (!dataPtr) {
         nDataBytes = data.length * data.BYTES_PER_ELEMENT;
         dataPtr = Module._malloc(nDataBytes);
-        dataHeap = new Uint8Array(Module.HEAPU8.buffer, dataPtr, nDataBytes);
+        dataHeap = new Uint8Array(Module.memory.buffer, dataPtr, nDataBytes);
     }
     dataHeap.set(new Uint8Array(data.buffer, data.buffer.byteLength - nDataBytes));
     return Module._find_fundamental_frequency(dataPtr, data.length, samplingRate);    
 }
 
+/**
+ * Takes a pointer to a C-style string (ends in a 0), and interprets it as UTF-8.
+ */
+function copyCStr(ptr) {
+    var iter = ptr;
+
+    // ye olde 0 terminated string
+    function* collectCString() {
+        var memory = new Uint8Array(Module.memory.buffer);
+        while (memory[iter] !== 0) {
+            if (memory[iter] === undefined) {
+                throw new Error("Tried to read undef mem");
+            }
+            yield memory[iter];
+            iter += 1;
+        }
+    };
+
+    var buffer_as_u8 = new Uint8Array(collectCString());
+    var utf8Decoder = new TextDecoder("UTF-8");
+    var buffer_as_utf8 = utf8Decoder.decode(buffer_as_u8);
+    Module._free_str(ptr);
+    return buffer_as_utf8;
+}
+
 
 function hzToCentsError(hz) {
     return Module._hz_to_cents_error(hz);
 }
 
-var hzToPitch = function(hz) {
-    var wrapped = Module.cwrap('hz_to_pitch', 'string', ['number']);
-    hzToPitch = wrapped;
-    return wrapped(hz);
+function hzToPitch(hz) {
+    var strPtr = Module._hz_to_pitch(hz);
+    return copyCStr(strPtr);
 };
 
 function correlation(data, samplingRate) {
-- 
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