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use std::{env, mem, path::PathBuf, time::Duration};
#[cfg(not(target_arch = "wasm32"))]
use std::time::Instant;
#[cfg(target_arch = "wasm32")]
use web_time::Instant;
use parking_lot::Mutex;
use zng_txt::Txt;
use crate::{VIEW_MODE, VIEW_SERVER, VIEW_VERSION};
/// Configuration for starting a view-process.
#[derive(Clone, Debug)]
#[non_exhaustive]
pub struct ViewConfig {
/// The [`VERSION`] of the API crate in the app-process.
///
/// [`VERSION`]: crate::VERSION
pub version: Txt,
/// Name of the initial channel used in [`connect_view_process`] to setup the connections to the
/// client app-process.
///
/// [`connect_view_process`]: crate::ipc::connect_view_process
pub server_name: Txt,
/// If the server should consider all window requests, headless window requests.
pub headless: bool,
}
impl ViewConfig {
/// New config.
pub fn new(version: impl Into<Txt>, server_name: impl Into<Txt>, headless: bool) -> Self {
Self {
version: version.into(),
server_name: server_name.into(),
headless,
}
}
/// Reads config from environment variables set by the [`Controller`] in a view-process instance.
///
/// View API implementers should call this to get the config when it suspects that is running as a view-process.
/// Returns `Some(_)` if the process was initialized as a view-process.
///
/// [`Controller`]: crate::Controller
pub fn from_env() -> Option<Self> {
if let Ok(version) = env::var(VIEW_VERSION)
&& let Ok(server_name) = env::var(VIEW_SERVER)
{
let headless = env::var(VIEW_MODE).map(|m| m == "headless").unwrap_or(false);
Some(ViewConfig {
version: Txt::from_str(&version),
server_name: Txt::from_str(&server_name),
headless,
})
} else {
None
}
}
/// Returns `true` if the current process is awaiting for the config to start the
/// view process in the same process.
pub(crate) fn is_awaiting_same_process() -> bool {
matches!(*same_process().lock(), SameProcess::Awaiting)
}
/// Sets and unblocks the same-process config if there is a request.
///
/// # Panics
///
/// If there is no pending `wait_same_process`.
pub(crate) fn set_same_process(cfg: ViewConfig) {
if Self::is_awaiting_same_process() {
*same_process().lock() = SameProcess::Ready(cfg);
} else {
unreachable!("use `waiting_same_process` to check, then call `set_same_process` only once")
}
}
/// Wait for config from same-process.
///
/// View API implementers should call this to sign that view-process config should be send to the same process
/// and then start the "app-process" code path in a different thread. This function returns when the app code path sends
/// the "view-process" configuration.
pub fn wait_same_process() -> Self {
let _s = tracing::trace_span!("ViewConfig::wait_same_process").entered();
if !matches!(*same_process().lock(), SameProcess::Not) {
panic!("`wait_same_process` can only be called once");
}
*same_process().lock() = SameProcess::Awaiting;
let time = Instant::now();
let timeout = Duration::from_secs(5);
let sleep = Duration::from_millis(10);
while Self::is_awaiting_same_process() {
std::thread::sleep(sleep);
if time.elapsed() >= timeout {
panic!("timeout, `wait_same_process` waited for `{timeout:?}`");
}
}
match mem::replace(&mut *same_process().lock(), SameProcess::Done) {
SameProcess::Ready(cfg) => cfg,
_ => unreachable!(),
}
}
/// Assert that the [`VERSION`] is the same in the app-process and view-process.
///
/// This method must be called in the view-process implementation, it fails if the versions don't match, panics if
/// `is_same_process` or writes to *stderr* and exits with code .
///
/// [`VERSION`]: crate::VERSION
pub fn assert_version(&self, is_same_process: bool) {
if self.version != crate::VERSION {
let msg = format!(
"view API version is not equal, app-process: {}, view-process: {}",
self.version,
crate::VERSION
);
if is_same_process {
panic!("{}", msg)
} else {
eprintln!("{msg}");
zng_env::exit(i32::from_le_bytes(*b"vapi"));
}
}
}
/// Returns `true` if a view-process exited because of [`assert_version`].
///
/// [`assert_version`]: Self::assert_version
pub fn is_version_err(exit_code: Option<i32>, stderr: Option<&str>) -> bool {
exit_code.map(|e| e == i32::from_le_bytes(*b"vapi")).unwrap_or(false)
|| stderr.map(|s| s.contains("view API version is not equal")).unwrap_or(false)
}
}
enum SameProcess {
Not,
Awaiting,
Ready(ViewConfig),
Done,
}
// because some view libs are dynamically loaded this variable needs to be patchable.
//
// This follows the same idea as the "hot-reload" patches, just manually implemented.
static mut SAME_PROCESS: &Mutex<SameProcess> = &SAME_PROCESS_COLD;
static SAME_PROCESS_COLD: Mutex<SameProcess> = Mutex::new(SameProcess::Not);
fn same_process() -> &'static Mutex<SameProcess> {
// SAFETY: this is safe because SAME_PROCESS is only mutated on dynamic lib init, before any other code.
unsafe { *std::ptr::addr_of!(SAME_PROCESS) }
}
/// Dynamic view-process implementations must patch the static variables used by
/// the view-api. This patch also propagates the tracing and log contexts.
pub struct StaticPatch {
same_process: *const Mutex<SameProcess>,
tracing: tracing_shared::SharedLogger,
env_res: PathBuf,
env_config: PathBuf,
env_cache: PathBuf,
env_about: &'static zng_env::About,
}
impl StaticPatch {
/// Called in the main executable.
pub fn capture() -> Self {
Self {
same_process: same_process(),
tracing: tracing_shared::SharedLogger::new(),
env_res: zng_env::res(""),
env_config: zng_env::config(""),
env_cache: zng_env::cache(""),
env_about: zng_env::about(),
}
}
/// Called in the dynamic library.
///
/// # Safety
///
/// Only safe if it is the first view-process code to run in the dynamic library.
pub unsafe fn install(&self) {
// SAFETY: safety handled by the caller
unsafe {
*std::ptr::addr_of_mut!(SAME_PROCESS) = &*self.same_process;
}
self.tracing.install();
zng_env::init_res(self.env_res.clone());
zng_env::init_config(self.env_config.clone());
zng_env::init_cache(self.env_cache.clone());
zng_env::init(self.env_about.clone());
}
}