Support building and running on Android (#36)

* Include vendored source code for `openssl` and `sqlite` so that
  they can be built from source for the Android target.

* Add `login.toml`: a temp hack to specify your username and password
  on platforms where command-line arguments aren't supported,
  such as Android and other mobie platforms.
  * This file should not be committed to version control
    with a valid username and password; hence why it's in .gitignore.

* Switch to `log!()` and `error!()` macros instead of
  `println!()` and `eprintln!()`, which work on Android.

* Export environment variables that the `cc` crate relies on
  to build and link Android-specific native target libraries,
  which currently include openssl and sqlite.
  * These variables only affect builds for Android targets.
  * We have modified the upstream `cargo-makepad` to automatically export
    those environment variables for Android builds, which frees
    the app developer (us) from the burden of having to do so.
* We have also modified the upstream `cargo-makepad`
  to support installing the full Android NDK at the canonical path.
  * See <makepad/makepad#388>

*Add instructions for building and running Robrix on Android.

.gitignore

@@ -2,3 +2,6 @@
 .vscode
 
 .DS_Store
+
+## Temp hack to support login on mobile platforms.
+login.toml

Cargo.toml

@@ -19,6 +19,7 @@ metadata.makepad-auto-version = "zqpv-Yj-K7WNVK2I8h5Okhho46Q="
 [dependencies]
 makepad-widgets = { git = "https://github.com/makepad/makepad", branch = "rik" }
 
+
 anyhow = "1.0"
 chrono = "0.4"
 clap = { version = "4.0.16", features = ["derive"] }
@@ -37,6 +38,26 @@ unicode-segmentation = "1.10.1"
 url = "2.2.2"
 
 
+## On Android, we currently build OpenSSL and SQLite from
+## the vendored source code, because on macOS hosts there aren't yet
+## prebuilt versions readily available, nor easily-configured pkg-config sysroots
+## like there are on Linux.
+##
+## Even though we don't directly depend on these crates in Robrix,
+## specifying them here with the `vendored`/`bundled` features
+## will cause cargo to enable those features across the entire build
+## (called "feature unification", see https://doc.rust-lang.org/cargo/reference/features.html#feature-unification),
+## meaning that any other crate that depends on them will also use the vendored versions.
+##
+## Technically, we don't need these when building for Android on Linux systems,
+## but there's no way to specify that in Cargo.toml, so we just always include them.
+## Plus, this makes builds more reproducible across host systems,
+## and avoids the issue of needing to set up pkg-config sysroots on Linux.
+[target.'cfg(target_os = "android")'.dependencies]
+openssl = { version = "*", features = ["vendored"] }
+rusqlite = { version = "*", features = ["bundled"] }
+
+
 [package.metadata.docs.rs]
 all-features = true
 

README.md

@@ -8,7 +8,9 @@ Robrix is a Matrix chat client written in Rust to demonstrate the functionality
 
 ## Building and Running
 
-[Install Rust](https://www.rust-lang.org/tools/install), and then simply run:
+First, [install Rust](https://www.rust-lang.org/tools/install).
+
+Then, on desktop platforms (macOS, Linux, Windows), simply run:
 ```sh
 cargo run -- 'USERNAME' 'PASSWORD' ['HOMESERVER_URL']
 ```
@@ -19,6 +21,27 @@ cargo run -- 'USERNAME' 'PASSWORD' ['HOMESERVER_URL']
 * The `HOMESERVER_URL` argument is optional and uses the `"https://matrix-client.matrix.org/"` URL by default.
 
 
+### Building Robrix for Android
+
+1. Install the `cargo-makepad` build tool:
+```sh
+cargo install --force --git https://github.com/makepad/makepad.git --branch rik cargo-makepad
+```
+
+2. Use `cargo-makepad` to install the Android toolchain, with the full NDK:
+```sh
+cargo makepad android install-toolchain --full-ndk
+```
+
+3. Build and run Robrix using `cargo-makepad`:
+    * Fill in your username and password in the [`login.toml`](login.toml) file.
+    ```sh
+    cargo makepad android run -p robrix --release
+    ```
+    * You'll need to connect a physical Android device with developer options enabled, or start up an emulator using Android Studio.
+        > API version 33 or higher is required, which is Android 13 and up.
+
+
 ## Feature status tracker 
 
 These are generally sorted in order of priority. If you're interested in helping out with anything here, please reach out via a GitHub issue or on our Robius matrix channel.
@@ -40,12 +63,12 @@ These are generally sorted in order of priority. If you're interested in helping
 - [ ] Display reactions (annotations)
 - [ ] Inline link previews
 - [ ] Inline reply view
+- [x] Send messages (standalone, no replies)
 - [ ] Interactive reaction button, send reactions
 - [ ] Reply button, send reply
 - [ ] Error display banners: no connection, failure to login, sync timeout.
 - [ ] Collapsible/expandable view of contiguous "small" events
 - [ ] Encrypted rooms, decrypting messages
-- [ ] Sending messages
 
 ### Auxiliary/admin features: login, registration, settings
 - [ ] Username/password login screen

login.toml

@@ -0,0 +1,19 @@
+username = " "
+password = " "
+
+### Please fill in your username and password above.
+###
+### Robrix does not yet have a login splash screen.
+### Thus, on desktop platforms, we allow the user to
+### pass in a username and password as command line arguments.
+###
+### However, on mobile platforms, there is no way to reliably
+### pass in command line arguments.
+### Instead, we enable the mobile apps to read them from a copy
+### of this file that is included in the app package files.
+###
+### Only the two username and password fields are supported.
+###
+### Note that for obvious reasons you should not commit this file
+### or upload it to a public repo with your actual username and password in it.
+### Thus, we have added it to the .gitignore file.

src/app.rs

@@ -258,7 +258,7 @@ impl LiveRegister for App {
 }
 impl LiveHook for App {
     fn after_new_from_doc(&mut self, _cx: &mut Cx) {
-        println!("after_new_from_doc(): starting matrix sdk loop");
+        log!("after_new_from_doc(): starting matrix sdk loop");
         crate::sliding_sync::start_matrix_tokio().unwrap();
     }
 }