diff options
Diffstat (limited to 'third_party/rust/android_logger/src/lib.rs')
| -rw-r--r-- | third_party/rust/android_logger/src/lib.rs | 670 |
1 files changed, 670 insertions, 0 deletions
diff --git a/third_party/rust/android_logger/src/lib.rs b/third_party/rust/android_logger/src/lib.rs new file mode 100644 index 0000000000..0446fad755 --- /dev/null +++ b/third_party/rust/android_logger/src/lib.rs @@ -0,0 +1,670 @@ +// Copyright 2016 The android_logger Developers +// +// Licensed under the Apache License, Version 2.0, <LICENSE-APACHE or +// http://apache.org/licenses/LICENSE-2.0> or the MIT license <LICENSE-MIT or +// http://opensource.org/licenses/MIT>, at your option. This file may not be +// copied, modified, or distributed except according to those terms. + +//! A logger which writes to android output. +//! +//! ## Example +//! +//! ``` +//! #[macro_use] extern crate log; +//! extern crate android_logger; +//! +//! use log::LevelFilter; +//! use android_logger::Config; +//! +//! /// Android code may not have obvious "main", this is just an example. +//! fn main() { +//! android_logger::init_once( +//! Config::default().with_max_level(LevelFilter::Trace), +//! ); +//! +//! debug!("this is a debug {}", "message"); +//! error!("this is printed by default"); +//! } +//! ``` +//! +//! ## Example with module path filter +//! +//! It is possible to limit log messages to output from a specific crate, +//! and override the logcat tag name (by default, the crate name is used): +//! +//! ``` +//! #[macro_use] extern crate log; +//! extern crate android_logger; +//! +//! use log::LevelFilter; +//! use android_logger::{Config,FilterBuilder}; +//! +//! fn main() { +//! android_logger::init_once( +//! Config::default() +//! .with_max_level(LevelFilter::Trace) +//! .with_tag("mytag") +//! .with_filter(FilterBuilder::new().parse("debug,hello::crate=trace").build()), +//! ); +//! +//! // .. +//! } +//! ``` +//! +//! ## Example with a custom log formatter +//! +//! ``` +//! use android_logger::Config; +//! +//! android_logger::init_once( +//! Config::default() +//! .with_max_level(log::LevelFilter::Trace) +//! .format(|f, record| write!(f, "my_app: {}", record.args())) +//! ) +//! ``` + +#[cfg(target_os = "android")] +extern crate android_log_sys as log_ffi; +extern crate once_cell; +use once_cell::sync::OnceCell; +#[macro_use] +extern crate log; + +extern crate env_logger; + +use log::{Level, LevelFilter, Log, Metadata, Record}; +#[cfg(target_os = "android")] +use log_ffi::LogPriority; +use std::ffi::{CStr, CString}; +use std::fmt; +use std::mem::{self, MaybeUninit}; +use std::ptr; + +pub use env_logger::filter::{Builder as FilterBuilder, Filter}; +pub use env_logger::fmt::Formatter; + +pub(crate) type FormatFn = Box<dyn Fn(&mut dyn fmt::Write, &Record) -> fmt::Result + Sync + Send>; + +/// Output log to android system. +#[cfg(target_os = "android")] +fn android_log(prio: log_ffi::LogPriority, tag: &CStr, msg: &CStr) { + unsafe { + log_ffi::__android_log_write( + prio as log_ffi::c_int, + tag.as_ptr() as *const log_ffi::c_char, + msg.as_ptr() as *const log_ffi::c_char, + ) + }; +} + +/// Dummy output placeholder for tests. +#[cfg(not(target_os = "android"))] +fn android_log(_priority: Level, _tag: &CStr, _msg: &CStr) {} + +/// Underlying android logger backend +pub struct AndroidLogger { + config: OnceCell<Config>, +} + +impl AndroidLogger { + /// Create new logger instance from config + pub fn new(config: Config) -> AndroidLogger { + AndroidLogger { + config: OnceCell::from(config), + } + } + + fn config(&self) -> &Config { + self.config.get_or_init(Config::default) + } +} + +static ANDROID_LOGGER: OnceCell<AndroidLogger> = OnceCell::new(); + +const LOGGING_TAG_MAX_LEN: usize = 23; +const LOGGING_MSG_MAX_LEN: usize = 4000; + +impl Default for AndroidLogger { + /// Create a new logger with default config + fn default() -> AndroidLogger { + AndroidLogger { + config: OnceCell::from(Config::default()), + } + } +} + +impl Log for AndroidLogger { + fn enabled(&self, metadata: &Metadata) -> bool { + let config = self.config(); + // todo: consider __android_log_is_loggable. + metadata.level() <= config.log_level.unwrap_or_else(log::max_level) + } + + fn log(&self, record: &Record) { + let config = self.config(); + + if !self.enabled(record.metadata()) { + return; + } + + // this also checks the level, but only if a filter was + // installed. + if !config.filter_matches(record) { + return; + } + + // tag must not exceed LOGGING_TAG_MAX_LEN + let mut tag_bytes: [MaybeUninit<u8>; LOGGING_TAG_MAX_LEN + 1] = uninit_array(); + + let module_path = record.module_path().unwrap_or_default().to_owned(); + + // If no tag was specified, use module name + let custom_tag = &config.tag; + let tag = custom_tag + .as_ref() + .map(|s| s.as_bytes()) + .unwrap_or_else(|| module_path.as_bytes()); + + // truncate the tag here to fit into LOGGING_TAG_MAX_LEN + self.fill_tag_bytes(&mut tag_bytes, tag); + // use stack array as C string + let tag: &CStr = unsafe { CStr::from_ptr(mem::transmute(tag_bytes.as_ptr())) }; + + // message must not exceed LOGGING_MSG_MAX_LEN + // therefore split log message into multiple log calls + let mut writer = PlatformLogWriter::new(record.level(), tag); + + // If a custom tag is used, add the module path to the message. + // Use PlatformLogWriter to output chunks if they exceed max size. + let _ = match (custom_tag, &config.custom_format) { + (_, Some(format)) => format(&mut writer, record), + (Some(_), _) => fmt::write( + &mut writer, + format_args!("{}: {}", module_path, *record.args()), + ), + _ => fmt::write(&mut writer, *record.args()), + }; + + // output the remaining message (this would usually be the most common case) + writer.flush(); + } + + fn flush(&self) {} +} + +impl AndroidLogger { + fn fill_tag_bytes(&self, array: &mut [MaybeUninit<u8>], tag: &[u8]) { + if tag.len() > LOGGING_TAG_MAX_LEN { + for (input, output) in tag + .iter() + .take(LOGGING_TAG_MAX_LEN - 2) + .chain(b"..\0".iter()) + .zip(array.iter_mut()) + { + output.write(*input); + } + } else { + for (input, output) in tag.iter().chain(b"\0".iter()).zip(array.iter_mut()) { + output.write(*input); + } + } + } +} + +/// Filter for android logger. +#[derive(Default)] +pub struct Config { + log_level: Option<LevelFilter>, + filter: Option<env_logger::filter::Filter>, + tag: Option<CString>, + custom_format: Option<FormatFn>, +} + +impl Config { + // TODO: Remove on 0.13 version release. + /// **DEPRECATED**, use [`Config::with_max_level()`] instead. + #[deprecated(note = "use `.with_max_level()` instead")] + pub fn with_min_level(self, level: Level) -> Self { + self.with_max_level(level.to_level_filter()) + } + + /// Changes the maximum log level. + /// + /// Note, that `Trace` is the maximum level, because it provides the + /// maximum amount of detail in the emitted logs. + /// + /// If `Off` level is provided, then nothing is logged at all. + /// + /// [`log::max_level()`] is considered as the default level. + pub fn with_max_level(mut self, level: LevelFilter) -> Self { + self.log_level = Some(level); + self + } + + fn filter_matches(&self, record: &Record) -> bool { + if let Some(ref filter) = self.filter { + filter.matches(record) + } else { + true + } + } + + pub fn with_filter(mut self, filter: env_logger::filter::Filter) -> Self { + self.filter = Some(filter); + self + } + + pub fn with_tag<S: Into<Vec<u8>>>(mut self, tag: S) -> Self { + self.tag = Some(CString::new(tag).expect("Can't convert tag to CString")); + self + } + + /// Sets the format function for formatting the log output. + /// ``` + /// # use android_logger::Config; + /// android_logger::init_once( + /// Config::default() + /// .with_max_level(log::LevelFilter::Trace) + /// .format(|f, record| write!(f, "my_app: {}", record.args())) + /// ) + /// ``` + pub fn format<F>(mut self, format: F) -> Self + where + F: Fn(&mut dyn fmt::Write, &Record) -> fmt::Result + Sync + Send + 'static, + { + self.custom_format = Some(Box::new(format)); + self + } +} + +pub struct PlatformLogWriter<'a> { + #[cfg(target_os = "android")] + priority: LogPriority, + #[cfg(not(target_os = "android"))] + priority: Level, + len: usize, + last_newline_index: usize, + tag: &'a CStr, + buffer: [MaybeUninit<u8>; LOGGING_MSG_MAX_LEN + 1], +} + +impl<'a> PlatformLogWriter<'a> { + #[cfg(target_os = "android")] + pub fn new_with_priority(priority: log_ffi::LogPriority, tag: &CStr) -> PlatformLogWriter { + #[allow(deprecated)] // created an issue #35 for this + PlatformLogWriter { + priority, + len: 0, + last_newline_index: 0, + tag, + buffer: uninit_array(), + } + } + + #[cfg(target_os = "android")] + pub fn new(level: Level, tag: &CStr) -> PlatformLogWriter { + Self::new_with_priority( + match level { + Level::Warn => LogPriority::WARN, + Level::Info => LogPriority::INFO, + Level::Debug => LogPriority::DEBUG, + Level::Error => LogPriority::ERROR, + Level::Trace => LogPriority::VERBOSE, + }, + tag, + ) + } + + #[cfg(not(target_os = "android"))] + pub fn new(level: Level, tag: &CStr) -> PlatformLogWriter { + #[allow(deprecated)] // created an issue #35 for this + PlatformLogWriter { + priority: level, + len: 0, + last_newline_index: 0, + tag, + buffer: uninit_array(), + } + } + + /// Flush some bytes to android logger. + /// + /// If there is a newline, flush up to it. + /// If ther was no newline, flush all. + /// + /// Not guaranteed to flush everything. + fn temporal_flush(&mut self) { + let total_len = self.len; + + if total_len == 0 { + return; + } + + if self.last_newline_index > 0 { + let copy_from_index = self.last_newline_index; + let remaining_chunk_len = total_len - copy_from_index; + + self.output_specified_len(copy_from_index); + self.copy_bytes_to_start(copy_from_index, remaining_chunk_len); + self.len = remaining_chunk_len; + } else { + self.output_specified_len(total_len); + self.len = 0; + } + self.last_newline_index = 0; + } + + /// Flush everything remaining to android logger. + pub fn flush(&mut self) { + let total_len = self.len; + + if total_len == 0 { + return; + } + + self.output_specified_len(total_len); + self.len = 0; + self.last_newline_index = 0; + } + + /// Output buffer up until the \0 which will be placed at `len` position. + fn output_specified_len(&mut self, len: usize) { + let mut last_byte = MaybeUninit::new(b'\0'); + + mem::swap(&mut last_byte, unsafe { + self.buffer.get_unchecked_mut(len) + }); + + let msg: &CStr = unsafe { CStr::from_ptr(self.buffer.as_ptr().cast()) }; + android_log(self.priority, self.tag, msg); + + unsafe { *self.buffer.get_unchecked_mut(len) = last_byte }; + } + + /// Copy `len` bytes from `index` position to starting position. + fn copy_bytes_to_start(&mut self, index: usize, len: usize) { + let dst = self.buffer.as_mut_ptr(); + let src = unsafe { self.buffer.as_ptr().add(index) }; + unsafe { ptr::copy(src, dst, len) }; + } +} + +impl<'a> fmt::Write for PlatformLogWriter<'a> { + fn write_str(&mut self, s: &str) -> fmt::Result { + let mut incomming_bytes = s.as_bytes(); + + while !incomming_bytes.is_empty() { + let len = self.len; + + // write everything possible to buffer and mark last \n + let new_len = len + incomming_bytes.len(); + let last_newline = self.buffer[len..LOGGING_MSG_MAX_LEN] + .iter_mut() + .zip(incomming_bytes) + .enumerate() + .fold(None, |acc, (i, (output, input))| { + output.write(*input); + if *input == b'\n' { + Some(i) + } else { + acc + } + }); + + // update last \n index + if let Some(newline) = last_newline { + self.last_newline_index = len + newline; + } + + // calculate how many bytes were written + let written_len = if new_len <= LOGGING_MSG_MAX_LEN { + // if the len was not exceeded + self.len = new_len; + new_len - len // written len + } else { + // if new length was exceeded + self.len = LOGGING_MSG_MAX_LEN; + self.temporal_flush(); + + LOGGING_MSG_MAX_LEN - len // written len + }; + + incomming_bytes = &incomming_bytes[written_len..]; + } + + Ok(()) + } +} + +/// Send a log record to Android logging backend. +/// +/// This action does not require initialization. However, without initialization it +/// will use the default filter, which allows all logs. +pub fn log(record: &Record) { + ANDROID_LOGGER + .get_or_init(AndroidLogger::default) + .log(record) +} + +/// Initializes the global logger with an android logger. +/// +/// This can be called many times, but will only initialize logging once, +/// and will not replace any other previously initialized logger. +/// +/// It is ok to call this at the activity creation, and it will be +/// repeatedly called on every lifecycle restart (i.e. screen rotation). +pub fn init_once(config: Config) { + let log_level = config.log_level; + let logger = ANDROID_LOGGER.get_or_init(|| AndroidLogger::new(config)); + + if let Err(err) = log::set_logger(logger) { + debug!("android_logger: log::set_logger failed: {}", err); + } else if let Some(level) = log_level { + log::set_max_level(level); + } +} + +// FIXME: When `maybe_uninit_uninit_array ` is stabilized, use it instead of this helper +fn uninit_array<const N: usize, T>() -> [MaybeUninit<T>; N] { + // SAFETY: Array contains MaybeUninit, which is fine to be uninit + unsafe { MaybeUninit::uninit().assume_init() } +} + +#[cfg(test)] +mod tests { + use super::*; + use std::fmt::Write; + use std::sync::atomic::{AtomicBool, Ordering}; + + #[test] + fn check_config_values() { + // Filter is checked in config_filter_match below. + let config = Config::default() + .with_max_level(LevelFilter::Trace) + .with_tag("my_app"); + + assert_eq!(config.log_level, Some(LevelFilter::Trace)); + assert_eq!(config.tag, Some(CString::new("my_app").unwrap())); + } + + #[test] + fn log_calls_formatter() { + static FORMAT_FN_WAS_CALLED: AtomicBool = AtomicBool::new(false); + let config = Config::default() + .with_max_level(LevelFilter::Info) + .format(|_, _| { + FORMAT_FN_WAS_CALLED.store(true, Ordering::SeqCst); + Ok(()) + }); + let logger = AndroidLogger::new(config); + + logger.log(&Record::builder().level(Level::Info).build()); + + assert!(FORMAT_FN_WAS_CALLED.load(Ordering::SeqCst)); + } + + #[test] + fn logger_enabled_threshold() { + let logger = AndroidLogger::new(Config::default().with_max_level(LevelFilter::Info)); + + assert!(logger.enabled(&log::MetadataBuilder::new().level(Level::Warn).build())); + assert!(logger.enabled(&log::MetadataBuilder::new().level(Level::Info).build())); + assert!(!logger.enabled(&log::MetadataBuilder::new().level(Level::Debug).build())); + } + + // Test whether the filter gets called correctly. Not meant to be exhaustive for all filter + // options, as these are handled directly by the filter itself. + #[test] + fn config_filter_match() { + let info_record = Record::builder().level(Level::Info).build(); + let debug_record = Record::builder().level(Level::Debug).build(); + + let info_all_filter = env_logger::filter::Builder::new().parse("info").build(); + let info_all_config = Config::default().with_filter(info_all_filter); + + assert!(info_all_config.filter_matches(&info_record)); + assert!(!info_all_config.filter_matches(&debug_record)); + } + + #[test] + fn fill_tag_bytes_truncates_long_tag() { + let logger = AndroidLogger::new(Config::default()); + let too_long_tag: [u8; LOGGING_TAG_MAX_LEN + 20] = [b'a'; LOGGING_TAG_MAX_LEN + 20]; + + let mut result: [MaybeUninit<u8>; LOGGING_TAG_MAX_LEN + 1] = uninit_array(); + logger.fill_tag_bytes(&mut result, &too_long_tag); + + let mut expected_result = [b'a'; LOGGING_TAG_MAX_LEN - 2].to_vec(); + expected_result.extend("..\0".as_bytes()); + assert_eq!(unsafe { assume_init_slice(&result) }, expected_result); + } + + #[test] + fn fill_tag_bytes_keeps_short_tag() { + let logger = AndroidLogger::new(Config::default()); + let short_tag: [u8; 3] = [b'a'; 3]; + + let mut result: [MaybeUninit<u8>; LOGGING_TAG_MAX_LEN + 1] = uninit_array(); + logger.fill_tag_bytes(&mut result, &short_tag); + + let mut expected_result = short_tag.to_vec(); + expected_result.push(0); + assert_eq!(unsafe { assume_init_slice(&result[..4]) }, expected_result); + } + + #[test] + fn platform_log_writer_init_values() { + let tag = CStr::from_bytes_with_nul(b"tag\0").unwrap(); + + let writer = PlatformLogWriter::new(Level::Warn, tag); + + assert_eq!(writer.tag, tag); + // Android uses LogPriority instead, which doesn't implement equality checks + #[cfg(not(target_os = "android"))] + assert_eq!(writer.priority, Level::Warn); + } + + #[test] + fn temporal_flush() { + let mut writer = get_tag_writer(); + + writer + .write_str("12\n\n567\n90") + .expect("Unable to write to PlatformLogWriter"); + + assert_eq!(writer.len, 10); + writer.temporal_flush(); + // Should have flushed up until the last newline. + assert_eq!(writer.len, 3); + assert_eq!(writer.last_newline_index, 0); + assert_eq!( + unsafe { assume_init_slice(&writer.buffer[..writer.len]) }, + "\n90".as_bytes() + ); + + writer.temporal_flush(); + // Should have flushed all remaining bytes. + assert_eq!(writer.len, 0); + assert_eq!(writer.last_newline_index, 0); + } + + #[test] + fn flush() { + let mut writer = get_tag_writer(); + writer + .write_str("abcdefghij\n\nklm\nnopqr\nstuvwxyz") + .expect("Unable to write to PlatformLogWriter"); + + writer.flush(); + + assert_eq!(writer.last_newline_index, 0); + assert_eq!(writer.len, 0); + } + + #[test] + fn last_newline_index() { + let mut writer = get_tag_writer(); + + writer + .write_str("12\n\n567\n90") + .expect("Unable to write to PlatformLogWriter"); + + assert_eq!(writer.last_newline_index, 7); + } + + #[test] + fn output_specified_len_leaves_buffer_unchanged() { + let mut writer = get_tag_writer(); + let log_string = "abcdefghij\n\nklm\nnopqr\nstuvwxyz"; + writer + .write_str(log_string) + .expect("Unable to write to PlatformLogWriter"); + + writer.output_specified_len(5); + + assert_eq!( + unsafe { assume_init_slice(&writer.buffer[..log_string.len()]) }, + log_string.as_bytes() + ); + } + + #[test] + fn copy_bytes_to_start() { + let mut writer = get_tag_writer(); + writer + .write_str("0123456789") + .expect("Unable to write to PlatformLogWriter"); + + writer.copy_bytes_to_start(3, 2); + + assert_eq!( + unsafe { assume_init_slice(&writer.buffer[..10]) }, + "3423456789".as_bytes() + ); + } + + #[test] + fn copy_bytes_to_start_nop() { + let test_string = "Test_string_with\n\n\n\nnewlines\n"; + let mut writer = get_tag_writer(); + writer + .write_str(test_string) + .expect("Unable to write to PlatformLogWriter"); + + writer.copy_bytes_to_start(0, 20); + writer.copy_bytes_to_start(10, 0); + + assert_eq!( + unsafe { assume_init_slice(&writer.buffer[..test_string.len()]) }, + test_string.as_bytes() + ); + } + + fn get_tag_writer() -> PlatformLogWriter<'static> { + PlatformLogWriter::new(Level::Warn, CStr::from_bytes_with_nul(b"tag\0").unwrap()) + } + + unsafe fn assume_init_slice<T>(slice: &[MaybeUninit<T>]) -> &[T] { + &*(slice as *const [MaybeUninit<T>] as *const [T]) + } +} |