Implement ADM using cubeb

.github/workflows/ringrtc.yml

@@ -26,6 +26,8 @@ jobs:
     steps:
     - name: Install protoc
       run: sudo apt-get update && sudo apt-get install -y protobuf-compiler
+    - name: Install cmake
+      run: sudo apt-get update && sudo apt-get install -y cmake
     - name: Install Python tools
       run: pip3 install flake8 mypy
     - uses: actions/checkout@v4
@@ -92,6 +94,8 @@ jobs:
     steps:
     - name: Install protoc
       run: sudo apt-get update && sudo apt-get install -y protobuf-compiler
+    - name: Install cmake
+      run: sudo apt-get update && sudo apt-get install -y cmake
     - uses: actions/checkout@v4
     - run: rustup toolchain install $(cat rust-toolchain) --profile minimal
     - name: Run rust tests
@@ -105,12 +109,12 @@ jobs:
         os: [ubuntu-latest, windows-latest, macos-13]
         include:
         - os: ubuntu-latest
-          install-deps: sudo apt-get update && sudo apt-get install -y protobuf-compiler
+          install-deps: sudo apt-get update && sudo apt-get install -y protobuf-compiler cmake
           test-runner: xvfb-run --auto-servernum
         - os: windows-latest
-          install-deps: choco install protoc
+          install-deps: choco install protoc cmake
         - os: macos-13
-          install-deps: brew install protobuf coreutils
+          install-deps: brew install protobuf coreutils cmake
     runs-on: ${{ matrix.os }}
     defaults:
       run:
@@ -140,9 +144,9 @@ jobs:
         os: [ubuntu-latest, macos-13]
         include:
         - os: ubuntu-latest
-          install-deps: sudo apt-get update && sudo apt-get install -y protobuf-compiler
+          install-deps: sudo apt-get update && sudo apt-get install -y protobuf-compiler cmake
         - os: macos-13
-          install-deps: brew install protobuf coreutils
+          install-deps: brew install protobuf coreutils cmake
     runs-on: ${{ matrix.os }}
     defaults:
       run:

BUILDING.md

@@ -26,6 +26,17 @@ Install rustup, the Rust management system:
 
 We use a pinned nightly toolchain for official builds, specified by our [rust-toolchain file](https://github.com/signalapp/ringrtc/blob/master/rust-toolchain) ([more information](https://rust-lang.github.io/rustup/overrides.html)).
 
+
+### cmake
+
+For Desktop builds, one of ringrtc's dependencies relies on `cmake` being
+available. This can be installed via some package managers, such as:
+
+    brew install cmake  # MacOS dev machine
+
+If it is not available in your system's package manger, see
+https://cmake.org/download/.
+
 #### Android
 
 Install Rust target support for Android via `rustup`:

Cargo.lock

@@ -352,7 +352,7 @@ version = "0.69.4"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "a00dc851838a2120612785d195287475a3ac45514741da670b735818822129a0"
 dependencies = [
- "bitflags",
+ "bitflags 2.6.0",
  "cexpr",
  "clang-sys",
  "itertools",
@@ -369,6 +369,12 @@ dependencies = [
  "which",
 ]
 
+[[package]]
+name = "bitflags"
+version = "1.3.2"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "bef38d45163c2f1dde094a7dfd33ccf595c92905c8f8f4fdc18d06fb1037718a"
+
 [[package]]
 name = "bitflags"
 version = "2.6.0"
@@ -749,6 +755,35 @@ dependencies = [
  "cipher",
 ]
 
+[[package]]
+name = "cubeb"
+version = "0.14.0"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "46141374032595c0fa92563b6ff21c2fef695c4e932ab1a35d8726d78b35255d"
+dependencies = [
+ "cubeb-core",
+]
+
+[[package]]
+name = "cubeb-core"
+version = "0.14.0"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "2e9d9d5a70e005de5a7ca350d973822702244af08c0e0720112641a799d8be4c"
+dependencies = [
+ "bitflags 1.3.2",
+ "cubeb-sys",
+]
+
+[[package]]
+name = "cubeb-sys"
+version = "0.14.0"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "192cd49cc8485ceb2b9d82ba7ca583af01b9b0a9251f4128550d154b06702c6e"
+dependencies = [
+ "cmake",
+ "pkg-config",
+]
+
 [[package]]
 name = "curve25519-dalek"
 version = "4.1.3"
@@ -1563,7 +1598,7 @@ version = "0.1.3"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "c0ff37bd590ca25063e35af745c343cb7a0271906fb7b37e4813e8f79f00268d"
 dependencies = [
- "bitflags",
+ "bitflags 2.6.0",
  "libc",
 ]
 
@@ -2236,6 +2271,8 @@ dependencies = [
  "chrono",
  "clap",
  "ctr",
+ "cubeb",
+ "cubeb-core",
  "env_logger",
  "fern",
  "futures",
@@ -2271,6 +2308,7 @@ dependencies = [
  "tower",
  "ureq",
  "uuid",
+ "windows 0.58.0",
  "x25519-dalek",
  "zkgroup",
 ]
@@ -2302,7 +2340,7 @@ version = "0.38.34"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "70dc5ec042f7a43c4a73241207cecc9873a06d45debb38b329f8541d85c2730f"
 dependencies = [
- "bitflags",
+ "bitflags 2.6.0",
  "errno",
  "libc",
  "linux-raw-sys",
@@ -2624,7 +2662,7 @@ dependencies = [
  "libc",
  "memchr",
  "ntapi",
- "windows",
+ "windows 0.57.0",
 ]
 
 [[package]]
@@ -3153,6 +3191,16 @@ dependencies = [
  "windows-targets 0.52.6",
 ]
 
+[[package]]
+name = "windows"
+version = "0.58.0"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "dd04d41d93c4992d421894c18c8b43496aa748dd4c081bac0dc93eb0489272b6"
+dependencies = [
+ "windows-core 0.58.0",
+ "windows-targets 0.52.6",
+]
+
 [[package]]
 name = "windows-core"
 version = "0.52.0"
@@ -3168,9 +3216,22 @@ version = "0.57.0"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "d2ed2439a290666cd67ecce2b0ffaad89c2a56b976b736e6ece670297897832d"
 dependencies = [
- "windows-implement",
+ "windows-implement 0.57.0",
- "windows-interface",
+ "windows-interface 0.57.0",
- "windows-result",
+ "windows-result 0.1.2",
+ "windows-targets 0.52.6",
+]
+
+[[package]]
+name = "windows-core"
+version = "0.58.0"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "6ba6d44ec8c2591c134257ce647b7ea6b20335bf6379a27dac5f1641fcf59f99"
+dependencies = [
+ "windows-implement 0.58.0",
+ "windows-interface 0.58.0",
+ "windows-result 0.2.0",
+ "windows-strings",
  "windows-targets 0.52.6",
 ]
 
@@ -3185,6 +3246,17 @@ dependencies = [
  "syn 2.0.71",
 ]
 
+[[package]]
+name = "windows-implement"
+version = "0.58.0"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "2bbd5b46c938e506ecbce286b6628a02171d56153ba733b6c741fc627ec9579b"
+dependencies = [
+ "proc-macro2",
+ "quote",
+ "syn 2.0.71",
+]
+
 [[package]]
 name = "windows-interface"
 version = "0.57.0"
@@ -3196,6 +3268,17 @@ dependencies = [
  "syn 2.0.71",
 ]
 
+[[package]]
+name = "windows-interface"
+version = "0.58.0"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "053c4c462dc91d3b1504c6fe5a726dd15e216ba718e84a0e46a88fbe5ded3515"
+dependencies = [
+ "proc-macro2",
+ "quote",
+ "syn 2.0.71",
+]
+
 [[package]]
 name = "windows-result"
 version = "0.1.2"
@@ -3205,6 +3288,25 @@ dependencies = [
  "windows-targets 0.52.6",
 ]
 
+[[package]]
+name = "windows-result"
+version = "0.2.0"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "1d1043d8214f791817bab27572aaa8af63732e11bf84aa21a45a78d6c317ae0e"
+dependencies = [
+ "windows-targets 0.52.6",
+]
+
+[[package]]
+name = "windows-strings"
+version = "0.1.0"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "4cd9b125c486025df0eabcb585e62173c6c9eddcec5d117d3b6e8c30e2ee4d10"
+dependencies = [
+ "windows-result 0.2.0",
+ "windows-targets 0.52.6",
+]
+
 [[package]]
 name = "windows-sys"
 version = "0.45.0"

acknowledgments/acknowledgments.html

@@ -45,11 +45,11 @@
     
         <h2>Overview of licenses:</h2>
         <ul class="licenses-overview">
-            <li><a href="#MIT">MIT License</a> (147)</li>
+            <li><a href="#MIT">MIT License</a> (157)</li>
             <li><a href="#AGPL-3.0">GNU Affero General Public License v3.0</a> (11)</li>
             <li><a href="#Apache-2.0">Apache License 2.0</a> (5)</li>
             <li><a href="#BSD-3-Clause">BSD 3-Clause &quot;New&quot; or &quot;Revised&quot; License</a> (4)</li>
-            <li><a href="#ISC">ISC License</a> (1)</li>
+            <li><a href="#ISC">ISC License</a> (4)</li>
             <li><a href="#Unicode-DFS-2016">Unicode License Agreement - Data Files and Software (2016)</a> (1)</li>
         </ul>
 
@@ -1534,6 +1534,29 @@ AUTHOR BE LIABLE FOR ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR
 WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN ACTION OF CONTRACT,
 NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF OR IN CONNECTION WITH THE USE OR PERFORMANCE OF
 THIS SOFTWARE.
+</pre>
+            </li>
+            <li class="license">
+                <h3 id="ISC">ISC License</h3>
+                <h4>Used by:</h4>
+                <ul class="license-used-by">
+                    <li><a href="https://github.com/mozilla/cubeb-rs">cubeb-core 0.14.0</a></li>
+                    <li><a href="https://github.com/mozilla/cubeb-rs">cubeb-sys 0.14.0</a></li>
+                    <li><a href="https://github.com/mozilla/cubeb-rs">cubeb 0.14.0</a></li>
+                </ul>
+                <pre class="license-text">Copyright © 2017 Mozilla Foundation
+
+Permission to use, copy, modify, and distribute this software for any
+purpose with or without fee is hereby granted, provided that the above
+copyright notice and this permission notice appear in all copies.
+
+THE SOFTWARE IS PROVIDED &quot;AS IS&quot; AND THE AUTHOR DISCLAIMS ALL WARRANTIES
+WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
+MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR
+ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
+WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
+ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF
+OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
 </pre>
             </li>
             <li class="license">
@@ -1709,7 +1732,10 @@ SOFTWARE.
                 <h3 id="MIT">MIT License</h3>
                 <h4>Used by:</h4>
                 <ul class="license-used-by">
+                    <li><a href="https://github.com/rust-lang/cc-rs">cc 1.1.5</a></li>
                     <li><a href="https://github.com/alexcrichton/cfg-if">cfg-if 1.0.0</a></li>
+                    <li><a href="https://github.com/rust-lang/cmake-rs">cmake 0.1.50</a></li>
+                    <li><a href="https://github.com/rust-lang/pkg-config-rs">pkg-config 0.3.30</a></li>
                 </ul>
                 <pre class="license-text">Copyright (c) 2014 Alex Crichton
 
@@ -1775,6 +1801,7 @@ DEALINGS IN THE SOFTWARE.
                 <h3 id="MIT">MIT License</h3>
                 <h4>Used by:</h4>
                 <ul class="license-used-by">
+                    <li><a href="https://github.com/bitflags/bitflags">bitflags 1.3.2</a></li>
                     <li><a href="https://github.com/bitflags/bitflags">bitflags 2.6.0</a></li>
                     <li><a href="https://github.com/rust-lang/log">log 0.4.22</a></li>
                     <li><a href="https://github.com/rust-lang/regex/tree/master/regex-automata">regex-automata 0.4.7</a></li>
@@ -3346,10 +3373,16 @@ SOFTWARE.
                     <li><a href="https://github.com/emk/cesu8-rs">cesu8 1.1.0</a></li>
                     <li><a href="https://github.com/neon-bindings/neon">neon 1.0.0</a></li>
                     <li><a href="https://github.com/microsoft/windows-rs">windows-core 0.57.0</a></li>
+                    <li><a href="https://github.com/microsoft/windows-rs">windows-core 0.58.0</a></li>
                     <li><a href="https://github.com/microsoft/windows-rs">windows-implement 0.57.0</a></li>
+                    <li><a href="https://github.com/microsoft/windows-rs">windows-implement 0.58.0</a></li>
                     <li><a href="https://github.com/microsoft/windows-rs">windows-interface 0.57.0</a></li>
+                    <li><a href="https://github.com/microsoft/windows-rs">windows-interface 0.58.0</a></li>
                     <li><a href="https://github.com/microsoft/windows-rs">windows-result 0.1.2</a></li>
+                    <li><a href="https://github.com/microsoft/windows-rs">windows-result 0.2.0</a></li>
+                    <li><a href="https://github.com/microsoft/windows-rs">windows-strings 0.1.0</a></li>
                     <li><a href="https://github.com/microsoft/windows-rs">windows 0.57.0</a></li>
+                    <li><a href="https://github.com/microsoft/windows-rs">windows 0.58.0</a></li>
                 </ul>
                 <pre class="license-text">MIT License
 

acknowledgments/acknowledgments.md

@@ -1453,6 +1453,25 @@ THIS SOFTWARE.
 
 ```
 
+## cubeb-core 0.14.0, cubeb-sys 0.14.0, cubeb 0.14.0
+
+```
+Copyright © 2017 Mozilla Foundation
+
+Permission to use, copy, modify, and distribute this software for any
+purpose with or without fee is hereby granted, provided that the above
+copyright notice and this permission notice appear in all copies.
+
+THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
+WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
+MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR
+ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
+WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
+ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF
+OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
+
+```
+
 ## windows-sys 0.45.0, windows-sys 0.52.0, windows-targets 0.42.2, windows-targets 0.52.6, windows_aarch64_msvc 0.42.2, windows_aarch64_msvc 0.52.6, windows_x86_64_gnu 0.52.6, windows_x86_64_msvc 0.42.2, windows_x86_64_msvc 0.52.6
 
 ```
@@ -1601,7 +1620,7 @@ SOFTWARE.
 
 ```
 
-## cfg-if 1.0.0
+## cc 1.1.5, cfg-if 1.0.0, cmake 0.1.50, pkg-config 0.3.30
 
 ```
 Copyright (c) 2014 Alex Crichton
@@ -1663,7 +1682,7 @@ DEALINGS IN THE SOFTWARE.
 
 ```
 
-## bitflags 2.6.0, log 0.4.22, regex-automata 0.4.7, regex-syntax 0.8.4, regex 1.10.5
+## bitflags 1.3.2, bitflags 2.6.0, log 0.4.22, regex-automata 0.4.7, regex-syntax 0.8.4, regex 1.10.5
 
 ```
 Copyright (c) 2014 The Rust Project Developers
@@ -3110,7 +3129,7 @@ SOFTWARE.
 
 ```
 
-## cesu8 1.1.0, neon 1.0.0, windows-core 0.57.0, windows-implement 0.57.0, windows-interface 0.57.0, windows-result 0.1.2, windows 0.57.0
+## cesu8 1.1.0, neon 1.0.0, windows-core 0.57.0, windows-core 0.58.0, windows-implement 0.57.0, windows-implement 0.58.0, windows-interface 0.57.0, windows-interface 0.58.0, windows-result 0.1.2, windows-result 0.2.0, windows-strings 0.1.0, windows 0.57.0, windows 0.58.0
 
 ```
 MIT License

acknowledgments/acknowledgments.plist

@@ -1499,6 +1499,29 @@ THIS SOFTWARE.
 			<key>Type</key>
 			<string>PSGroupSpecifier</string>
 		</dict>
+		<dict>
+			<key>FooterText</key>
+			<string>Copyright © 2017 Mozilla Foundation
+
+Permission to use, copy, modify, and distribute this software for any
+purpose with or without fee is hereby granted, provided that the above
+copyright notice and this permission notice appear in all copies.
+
+THE SOFTWARE IS PROVIDED &quot;AS IS&quot; AND THE AUTHOR DISCLAIMS ALL WARRANTIES
+WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
+MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR
+ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
+WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
+ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF
+OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
+</string>
+			<key>License</key>
+			<string>ISC License</string>
+			<key>Title</key>
+			<string>cubeb-core 0.14.0, cubeb-sys 0.14.0, cubeb 0.14.0</string>
+			<key>Type</key>
+			<string>PSGroupSpecifier</string>
+		</dict>
 		<dict>
 			<key>FooterText</key>
 			<string>    MIT License
@@ -1698,7 +1721,7 @@ DEALINGS IN THE SOFTWARE.
 			<key>License</key>
 			<string>MIT License</string>
 			<key>Title</key>
-			<string>cfg-if 1.0.0</string>
+			<string>cc 1.1.5, cfg-if 1.0.0, cmake 0.1.50, pkg-config 0.3.30</string>
 			<key>Type</key>
 			<string>PSGroupSpecifier</string>
 		</dict>
@@ -1768,7 +1791,7 @@ DEALINGS IN THE SOFTWARE.
 			<key>License</key>
 			<string>MIT License</string>
 			<key>Title</key>
-			<string>bitflags 2.6.0, log 0.4.22, regex-automata 0.4.7, regex-syntax 0.8.4, regex 1.10.5</string>
+			<string>bitflags 1.3.2, bitflags 2.6.0, log 0.4.22, regex-automata 0.4.7, regex-syntax 0.8.4, regex 1.10.5</string>
 			<key>Type</key>
 			<string>PSGroupSpecifier</string>
 		</dict>
@@ -3391,7 +3414,7 @@ THE SOFTWARE IS PROVIDED &quot;AS IS&quot;, WITHOUT WARRANTY OF ANY KIND, EXPRES
 			<key>License</key>
 			<string>MIT License</string>
 			<key>Title</key>
-			<string>cesu8 1.1.0, neon 1.0.0, windows-core 0.57.0, windows-implement 0.57.0, windows-interface 0.57.0, windows-result 0.1.2, windows 0.57.0</string>
+			<string>cesu8 1.1.0, neon 1.0.0, windows-core 0.57.0, windows-core 0.58.0, windows-implement 0.57.0, windows-implement 0.58.0, windows-interface 0.57.0, windows-interface 0.58.0, windows-result 0.1.2, windows-result 0.2.0, windows-strings 0.1.0, windows 0.57.0, windows 0.58.0</string>
 			<key>Type</key>
 			<string>PSGroupSpecifier</string>
 		</dict>

src/rust/Cargo.toml

@@ -94,6 +94,12 @@ chrono = {version = "0.4.38", optional = true }
 call_protobuf = { path = "../../protobuf", package = "protobuf"}
 mrp = { path = "../../mrp" }
 
+# Optional, needed by "native" feature
+cubeb = {  version = "0.14.0", optional = true }
+cubeb-core = {  version = "0.14.0", optional = true }
+# Only needed by native feature on windows
+windows = { version = "0.58.0", optional = true, features = ["Win32_System_Com"] }
+
 [target.'cfg(not(target_os="android"))'.dependencies]
 # sysinfo depends on getgrgid_r, which was added in Android API level 24
 sysinfo = { version = "0.31.2", default-features = false, features = ["system"] }
@@ -102,7 +108,7 @@ sysinfo = { version = "0.31.2", default-features = false, features = ["system"]
 default = []
 sim = []
 electron = ["neon", "native"]
-native = []
+native = ["cubeb", "cubeb-core", "windows"]
 prebuilt_webrtc = ["native"]
 simnet = ["injectable_network"]
 injectable_network = []

src/rust/src/lib.rs

@@ -91,6 +91,8 @@ pub mod webrtc {
     pub use arc::Arc;
     #[cfg(all(not(feature = "sim"), feature = "native"))]
     pub mod audio_device_module;
+    #[cfg(all(not(feature = "sim"), feature = "native"))]
+    pub mod audio_device_module_utils;
     pub mod field_trial;
     pub mod ice_gatherer;
     #[cfg(feature = "injectable_network")]

src/rust/src/webrtc/audio_device_module_utils.rs

@@ -0,0 +1,201 @@
+//
+// Copyright 2024 Signal Messenger, LLC
+// SPDX-License-Identifier: AGPL-3.0-only
+//
+
+//! Utility functions for audio_device_module.rs
+//! Nothing in here should depend on webrtc directly.
+
+use crate::webrtc;
+use anyhow::anyhow;
+use cubeb::{DeviceCollection, DeviceInfo, DeviceState};
+use cubeb_core::DevicePref;
+use std::ffi::{c_uchar, CString};
+
+/// Wrapper struct for DeviceCollection that handles default devices.
+pub struct DeviceCollectionWrapper<'a> {
+    device_collection: DeviceCollection<'a>,
+}
+
+impl DeviceCollectionWrapper<'_> {
+    pub fn new(device_collection: DeviceCollection<'_>) -> DeviceCollectionWrapper<'_> {
+        DeviceCollectionWrapper { device_collection }
+    }
+
+    /// Iterate over all Enabled devices (those that are plugged in and not disabled by the OS)
+    pub fn iter(
+        &self,
+    ) -> std::iter::Filter<std::slice::Iter<'_, DeviceInfo>, fn(&&DeviceInfo) -> bool> {
+        self.device_collection
+            .iter()
+            .filter(|d| d.state() == DeviceState::Enabled)
+    }
+
+    #[cfg(target_os = "windows")]
+    /// Get a specified device index, accounting for the two default devices.
+    pub fn get(&self, idx: usize) -> Option<&DeviceInfo> {
+        // 0 should be "default device" and 1 should be "default communications device".
+        // Note: On windows, CUBEB_DEVICE_PREF_VOICE will be set for default communications device,
+        // and CUBEB_DEVICE_PREF_MULTIMEDIA | CUBEB_DEVICE_PREF_NOTIFICATION for default device.
+        // https://github.com/mozilla/cubeb/blob/bbbe5bb0b29ed64cc7dd191d7a72fe24bba0d284/src/cubeb_wasapi.cpp#L3322
+        if self.count() == 0 {
+            None
+        } else if idx > 1 {
+            self.iter().nth(idx - 2)
+        } else if idx == 1 {
+            // Find a device that's preferred for VOICE -- device 1 is the "default communications"
+            self.iter()
+                .find(|&device| device.preferred().contains(DevicePref::VOICE))
+        } else {
+            // Find a device that's preferred for MULTIMEDIA -- device 0 is the "default"
+            self.iter()
+                .find(|&device| device.preferred().contains(DevicePref::MULTIMEDIA))
+        }
+    }
+
+    #[cfg(not(target_os = "windows"))]
+    /// Get a specified device index, accounting for the default device.
+    pub fn get(&self, idx: usize) -> Option<&DeviceInfo> {
+        if self.count() == 0 {
+            None
+        } else if idx > 0 {
+            self.iter().nth(idx - 1)
+        } else {
+            // Find a device that's preferred for VOICE -- device 0 is the "default"
+            self.iter()
+                .find(|&device| device.preferred().contains(DevicePref::VOICE))
+        }
+    }
+
+    #[cfg(target_os = "windows")]
+    /// Returns the number of devices.
+    /// Note: On Windows, this is 2 smaller than the number of addressable
+    /// devices, because the default device and default communications device
+    /// are not counted.
+    pub fn count(&self) -> usize {
+        self.iter().count()
+    }
+    #[cfg(not(target_os = "windows"))]
+    /// Returns the number of devices, counting the default device.
+    pub fn count(&self) -> usize {
+        let count = self.iter().count();
+        if count == 0 {
+            0
+        } else {
+            count + 1
+        }
+    }
+}
+
+/// Copy from |src| into |dest| at most |dest_size| - 1 bytes and write a nul terminator either after |src| or at the end of |dest_size|
+pub fn copy_and_truncate_string(
+    src: &str,
+    dest: webrtc::ptr::Borrowed<c_uchar>,
+    dest_size: usize,
+) -> anyhow::Result<()> {
+    // Leave room for the nul terminator.
+    let size = std::cmp::min(src.len(), dest_size - 1);
+    let c_str = CString::new(src.get(0..size).ok_or(anyhow!("couldn't get substring"))?)?;
+    let c_str_bytes = c_str.as_bytes_with_nul();
+    // Safety: dest has at least |dest_size| bytes allocated, and we won't
+    // write any more than that. In addition, we are copying from a slice that
+    // includes the nul-terminator, and we are not copying beyond the end of that
+    // slice.
+    unsafe {
+        std::ptr::copy(
+            c_str_bytes.as_ptr(),
+            std::ptr::from_mut(
+                dest.as_mut()
+                    .ok_or(anyhow!("couldn't get mutable pointer"))?,
+            ),
+            c_str_bytes.len(),
+        );
+    }
+    Ok(())
+}
+
+#[cfg(test)]
+mod audio_device_module_tests {
+    use super::*;
+    #[test]
+    // Verify that extremely long strings are properly truncated and
+    // nul-terminated
+    fn copy_and_truncate_long_string() {
+        let data = vec![0xaau8; 10];
+        let src = String::from_iter(['A'; 20]); // longer than data
+        let out = webrtc::ptr::Borrowed::from_ptr(data.as_ptr());
+        copy_and_truncate_string(&src, out, data.len()).unwrap();
+        let mut expected = vec![0x41u8; 9]; // 'A'
+        expected.push(0);
+        assert_eq!(data, expected);
+    }
+
+    #[test]
+    // Ensure that we do not read past the end of `src`
+    fn copy_and_truncate_short_string() {
+        let data = vec![0xaau8; 10];
+        let src = String::from_iter(['A'; 4]); // shorter than data
+        let out = webrtc::ptr::Borrowed::from_ptr(data.as_ptr());
+        copy_and_truncate_string(&src, out, data.len()).unwrap();
+        let expected = vec![0x41u8, 0x41, 0x41, 0x41, 0x0, 0xaa, 0xaa, 0xaa, 0xaa, 0xaa];
+        assert_eq!(data, expected);
+    }
+
+    #[test]
+    // Check for off-by-one errors
+    fn copy_and_truncate_max_len_string() {
+        let data = vec![0xaau8; 10];
+        let src = String::from_iter(['A'; 10]); // equal length to data
+        let out = webrtc::ptr::Borrowed::from_ptr(data.as_ptr());
+        copy_and_truncate_string(&src, out, data.len()).unwrap();
+        let mut expected = vec![0x41u8; 9]; // 'A'
+        expected.push(0);
+        assert_eq!(data, expected);
+    }
+
+    #[test]
+    // Check for off-by-one errors
+    fn copy_and_truncate_barely_short_string() {
+        let data = vec![0xaau8; 10];
+        let src = String::from_iter(['A'; 9]); // one shorter than data
+        let out = webrtc::ptr::Borrowed::from_ptr(data.as_ptr());
+        copy_and_truncate_string(&src, out, data.len()).unwrap();
+        let mut expected = vec![0x41u8; 9]; // 'A'
+        expected.push(0);
+        assert_eq!(data, expected);
+    }
+
+    #[test]
+    // Check for overwrite errors
+    fn copy_no_overwrite() {
+        let data = vec![0xaau8; 10];
+        let src = String::from_iter(['A'; 20]); // longer than data
+        let out = webrtc::ptr::Borrowed::from_ptr(data.as_ptr());
+        // State that data has one fewer byte than it actually does to make sure
+        // the function doesn't write past the end.
+        copy_and_truncate_string(&src, out, data.len() - 1).unwrap();
+        let mut expected = vec![0x41u8; 8]; // 'A'
+        expected.push(0);
+        expected.push(0xaa);
+        assert_eq!(data, expected);
+    }
+
+    #[test]
+    // Verify that a string with internal nul characters is handled gracefully.
+    fn string_with_nuls() {
+        let data = vec![0xaau8; 10];
+        let src = "a\0b";
+        let out = webrtc::ptr::Borrowed::from_ptr(data.as_ptr());
+        assert!(copy_and_truncate_string(src, out, data.len() - 1).is_err());
+        // data should be untouched
+        assert_eq!(data, vec![0xaau8; 10]);
+    }
+
+    #[test]
+    // Verify that a null dest pointer is handled gracefully
+    fn null_ptr() {
+        let src = "AA";
+        let out = webrtc::ptr::Borrowed::null();
+        assert!(copy_and_truncate_string(src, out, 5).is_err());
+    }
+}

src/rust/src/webrtc/ffi/audio_device_module.rs

@@ -8,15 +8,17 @@
 use crate::webrtc;
 use crate::webrtc::audio_device_module::{AudioDeviceModule, AudioLayer, WindowsDeviceType};
 use libc::size_t;
-use std::ffi::c_void;
+use std::ffi::{c_uchar, c_void};
-use std::os::raw::c_char;
 
-/// Incomplete type for C++ AudioTransport.
+/// Wrapper type for C++ AudioTransport.
-#[repr(C)]
+#[derive(Copy, Clone)]
 pub struct RffiAudioTransport {
-    _private: [u8; 0],
+    pub callback: *const c_void,
 }
 
+// Safety: managed by not allowing changes to the transport while playout or recording are in progress.
+unsafe impl Send for RffiAudioTransport {}
+
 /// all_adm_functions is a higher-level macro that enables "tt muncher" macros
 /// The list of functions MUST be kept in sync with AudioDeviceCallbacks in webrtc C++, and
 /// in particular the order must match.
@@ -25,7 +27,7 @@ macro_rules! all_adm_functions {
         $macro!(
             active_audio_layer(audio_layer: webrtc::ptr::Borrowed<AudioLayer>) -> i32;
 
-            register_audio_callback(audio_callback: webrtc::ptr::Borrowed<RffiAudioTransport>) -> i32;
+            register_audio_callback(audio_callback: *const c_void) -> i32;
 
             // Main initialization and termination
             init() -> i32;
@@ -35,8 +37,8 @@ macro_rules! all_adm_functions {
             // Device enumeration
             playout_devices() -> i16;
             recording_devices() -> i16;
-            playout_device_name(index: u16, name: webrtc::ptr::Borrowed<c_char>, guid: webrtc::ptr::Borrowed<c_char>) -> i32;
+            playout_device_name(index: u16, name: webrtc::ptr::Borrowed<c_uchar>, guid: webrtc::ptr::Borrowed<c_uchar>) -> i32;
-            recording_device_name(index: u16, name: webrtc::ptr::Borrowed<c_char>, guid: webrtc::ptr::Borrowed<c_char>) -> i32;
+            recording_device_name(index: u16, name: webrtc::ptr::Borrowed<c_uchar>, guid: webrtc::ptr::Borrowed<c_uchar>) -> i32;
 
             // Device selection
             set_playout_device(index: u16) -> i32;
@@ -136,7 +138,16 @@ macro_rules! adm_wrapper {
     () => {};
     ($f:ident($($param:ident: $arg_ty:ty),*) -> $ret:ty ; $($t:tt)*) => {
         extern "C" fn $f(ptr: webrtc::ptr::Borrowed<AudioDeviceModule>, $($param: $arg_ty),*) -> $ret {
-            debug!("{} wrapper", stringify!($f));
+            // Safety: Safe as long as this function is only called from a single thread, which will
+            // be the case.
+            static mut LOG_COUNT: i32 = 0;
+            unsafe {
+                if LOG_COUNT % 100 == 0 {
+                    info!("{} wrapper", stringify!($f));
+                    LOG_COUNT = 0;
+                }
+                LOG_COUNT += 1;
+            }
             if let Some(adm) = unsafe { ptr.as_mut() } {
                 adm.$f($($param),*)
             } else {
@@ -208,7 +219,7 @@ pub const AUDIO_DEVICE_CBS_PTR: *const AudioDeviceCallbacks = &AUDIO_DEVICE_CBS;
 
 extern "C" {
     pub fn Rust_recordedDataIsAvailable(
-        audio_transport: webrtc::ptr::Borrowed<RffiAudioTransport>,
+        audio_transport: *const c_void,
         audio_samples: *const c_void,
         n_samples: size_t,
         n_bytes_per_sample: size_t,
@@ -223,7 +234,7 @@ extern "C" {
     ) -> i32;
 
     pub fn Rust_needMorePlayData(
-        audio_transport: webrtc::ptr::Borrowed<RffiAudioTransport>,
+        audio_transport: *const c_void,
         n_samples: size_t,
         n_bytes_per_sample: size_t,
         n_channels: size_t,