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// Copyright © SixtyFPS GmbH <info@slint.dev>
// SPDX-License-Identifier: GPL-3.0-only OR LicenseRef-Slint-Royalty-free-2.0 OR LicenseRef-Slint-Software-3.0
/// Location information attached to a log message.
#[derive(Clone, Debug)]
pub struct LogMessageLocation<'a> {
/// The file path of the source that emitted the log message
pub path: &'a str,
/// the line number of the call that emitted the log message (1-based)
pub line: usize,
/// The column of the call that emitted the log message (1-based)
pub column: usize,
}
#[derive(Clone, Copy, Debug, Eq, PartialEq)]
#[non_exhaustive]
pub enum LogMessageSource {
/// The message originates from Slint source code (e.g. the `debug()` function in Slint)
SlintCode,
/// The message originates from the Slint runtime crates
///
/// For example if a file path could not be resolved at runtime.
Runtime,
}
/// Opaque log message, emitted by [`crate::debug_log!`] as well as the Slint `debug()` function.
pub struct LogMessage<'a> {
source: LogMessageSource,
location: Option<LogMessageLocation<'a>>,
arguments: core::fmt::Arguments<'a>,
}
impl<'a> LogMessage<'a> {
pub fn new(
source: LogMessageSource,
location: Option<LogMessageLocation<'a>>,
arguments: core::fmt::Arguments<'a>,
) -> Self {
Self { source, location, arguments }
}
pub fn source(&self) -> LogMessageSource {
self.source
}
pub fn location(&self) -> Option<LogMessageLocation<'_>> {
self.location.clone()
}
pub fn message_arguments(&self) -> core::fmt::Arguments<'a> {
self.arguments
}
}
/// Log message handler type stored in a [`crate::SlintContext`].
pub type LogMessageHandler = alloc::boxed::Box<dyn for<'a> Fn(LogMessage<'a>) + 'static>;
#[doc(hidden)]
pub fn log_message(message: LogMessage) {
crate::context::GLOBAL_CONTEXT.with(|p| match p.get() {
Some(ctx) => ctx.dispatch_log_message(message),
None => default_log_message(message.arguments),
});
}
#[doc(hidden)]
pub fn default_log_message(_arguments: core::fmt::Arguments) {
cfg_if::cfg_if! {
if #[cfg(feature = "log")] {
log::debug!("{_arguments}");
} else if #[cfg(target_arch = "wasm32")] {
use wasm_bindgen::prelude::*;
use std::string::ToString;
#[wasm_bindgen]
extern "C" {
#[wasm_bindgen(js_namespace = console)]
pub fn log(s: &str);
}
log(&_arguments.to_string());
} else if #[cfg(feature = "std")] {
use std::io::Write;
// We were seeing intermittent, albeit very rare, crashes due to `eprintln` panicking
// if the write to stderr fails. Since this is just for debug printing, it's safe
// to silently drop this if we can't write (since it wouldn't be written to stderr
// anyway)
let _ = writeln!(std::io::stderr(), "{_arguments}");
}
}
}
#[macro_export]
/// This macro allows producing debug output that will appear on stderr in regular builds
/// and in the console log for wasm builds.
macro_rules! debug_log {
($($t:tt)*) => ($crate::debug_log::log_message(
$crate::debug_log::LogMessage::new(
$crate::debug_log::LogMessageSource::Runtime,
None,
format_args!($($t)*),
)
))
}