Auto merge of #21812 - jdm:useful-output, r=SimonSapin

Provide useful defaults for Android logcat output

These changes integrate the stdout/stderr redirection from 0e80cfbcee/cargo-apk/injected-glue/lib.rs (L240-L303), and set up the default RUST_LOG filters so that useful JS errors and GL errors appear in the logcat output. I have verified that thread panics appear in output as well (without backtraces, sadly) by visiting https://acid3.acidtests.org.

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- [x] `./mach build -d` does not report any errors
- [x] `./mach test-tidy` does not report any errors
- [x] These changes fix #21637 and fix #21783
- [x] These changes do not require tests because no tests for logcat.

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bors-servo 2018-09-26 12:09:12 -04:00 committed by GitHub
commit 515afac456
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@ -10,11 +10,13 @@ use gl_glue;
use jni::{JNIEnv, JavaVM};
use jni::objects::{GlobalRef, JClass, JObject, JString, JValue};
use jni::sys::{jboolean, jfloat, jint, jstring, JNI_TRUE};
use libc::{pipe, dup2, read};
use log::Level;
use std;
use std::borrow::Cow;
use std::os::raw::c_void;
use std::os::raw::{c_char, c_int, c_void};
use std::sync::{Arc, Mutex};
use std::thread;
struct HostCallbacks {
callbacks: GlobalRef,
@ -61,11 +63,19 @@ pub fn Java_com_mozilla_servoview_JNIServo_init(
// Note: Android debug logs are stripped from a release build.
// debug!() will only show in a debug build. Use info!() if logs
// should show up in adb logcat with a release build.
let mut filter = Filter::default()
.with_min_level(Level::Debug)
.with_allowed_module_path("simpleservo::api")
.with_allowed_module_path("simpleservo::jniapi")
.with_allowed_module_path("simpleservo::gl_glue::egl");
let filters = [
"simpleservo::api",
"simpleservo::jniapi",
"simpleservo::gl_glue::egl",
// Show JS errors by default.
"script::dom::bindings::error",
// Show GL errors by default.
"canvas::webgl_thread",
];
let mut filter = Filter::default().with_min_level(Level::Debug);
for &module in &filters {
filter = filter.with_allowed_module_path(module);
}
let log_str = env.get_string(log_str).ok();
let log_str = log_str.as_ref().map_or(Cow::Borrowed(""), |s| s.to_string_lossy());
for module in log_str.split(',') {
@ -77,6 +87,7 @@ pub fn Java_com_mozilla_servoview_JNIServo_init(
info!("init");
initialize_android_glue(&env, activity);
redirect_stdout_to_logcat();
let args = env.get_string(args)
.expect("Couldn't get java string")
@ -434,3 +445,78 @@ fn initialize_android_glue(env: &JNIEnv, activity: JObject) {
ANDROID_APP = Box::into_raw(Box::new(app));
}
}
extern {
pub fn __android_log_write(prio: c_int, tag: *const c_char, text: *const c_char) -> c_int;
}
fn redirect_stdout_to_logcat() {
// The first step is to redirect stdout and stderr to the logs.
// We redirect stdout and stderr to a custom descriptor.
let mut pfd: [c_int; 2] = [0, 0];
unsafe {
pipe(pfd.as_mut_ptr());
dup2(pfd[1], 1);
dup2(pfd[1], 2);
}
let descriptor = pfd[0];
// Then we spawn a thread whose only job is to read from the other side of the
// pipe and redirect to the logs.
let _detached = thread::spawn(move || {
const BUF_LENGTH: usize = 512;
let mut buf = vec![b'\0' as c_char; BUF_LENGTH];
// Always keep at least one null terminator
const BUF_AVAILABLE: usize = BUF_LENGTH - 1;
let buf = &mut buf[..BUF_AVAILABLE];
let mut cursor = 0_usize;
let tag = b"simpleservo\0".as_ptr() as _;
loop {
let result = {
let read_into = &mut buf[cursor..];
unsafe {
read(descriptor, read_into.as_mut_ptr() as *mut _, read_into.len())
}
};
let end = if result == 0 {
return;
} else if result < 0 {
return; /* TODO: report problem */
} else {
result as usize + cursor
};
if let Some(last_newline_pos) = buf.iter().rposition(|&c| c == b'\n' as c_char) {
buf[last_newline_pos] = b'\0' as c_char;
unsafe {
__android_log_write(3, tag, buf.as_ptr());
}
if last_newline_pos < buf.len() - 1 {
let pos_after_newline = last_newline_pos + 1;
let len_not_logged_yet = buf[pos_after_newline..].len();
for j in 0..len_not_logged_yet as usize {
buf[j] = buf[pos_after_newline + j];
}
cursor = len_not_logged_yet;
} else {
cursor = 0;
}
} else if cursor == BUF_AVAILABLE {
// No newline found but the buffer is full, flush it anyway.
// `buf.as_ptr()` is null-terminated by BUF_LENGTH being 1 less than BUF_AVAILABLE.
unsafe {
__android_log_write(3, tag, buf.as_ptr());
}
cursor = 0;
} else {
cursor = end;
}
}
});
}