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//! Lightweight logging framework for resource constrained devices //! //! ![stlog running on a Cortex-M microcontroller][img] //! //! [img]: https://i.imgur.com/9K3SrI2.png //! //! # Features //! //! - `O(1)` runtime. Logging strings of arbitrary size takes a constant number //! of instructions. //! //! - `O(0)` memory usage. The logged strings are NOT stored in the device //! memory. //! //! - Supports different logging levels: trace, debug, info, warn and error. //! //! # Non-features //! //! - `printf` style or any other kind of formatting //! //! # Limitations //! //! - The current implementation only supports 256 different log strings. This //! restriction will be lifted in the future. //! //! # Requirements //! //! The device program must be stored in ELF format. //! //! The device linker script must allocate a `.stlog` section in the output ELF //! file as described below: //! //! ``` text //! SECTIONS //! { //! /* .. */ //! //! .stlog 0 (INFO) : { //! _sstlog_trace = .; //! *(.stlog.trace*); //! _estlog_trace = .; //! //! _sstlog_debug = .; //! *(.stlog.debug*); //! _estlog_debug = .; //! //! _sstlog_info = .; //! *(.stlog.info*); //! _estlog_info = .; //! //! _sstlog_warn = .; //! *(.stlog.warn*); //! _estlog_warn = .; //! //! _sstlog_error = .; //! *(.stlog.error*); //! _estlog_error = .; //! } //! //! /* .. */ //! } //! ``` //! //! # Example //! //! - Device side //! //! ``` ignore //! #[macro_use] //! extern crate stlog; //! //! struct Logger { .. } //! //! impl<'a> stlog::Logger for &'a Logger { .. } //! //! fn main() { //! let logger = Logger { .. }; //! //! info!(&logger, "Hello, world!"); //! warn!(&logger, "The quick brown fox jumps over the lazy dog."); //! } //! ``` //! //! - Host side //! //! ``` text //! $ # flash and execute the device program //! $ arm-none-eabi-gdb /path/to/device/binary & //! //! $ # stcat is required to decode strings logged via `stlog` //! $ cargo install stcat --vers 0.1.0 //! //! $ cat /dev/ttyUSB0 | stcat -e /path/to/device/binary //! INFO Hello, world! //! WARN The quick brown fox jumps over the lazy dog. //! ``` //! //! Assuming that the device is logging the strings through the `/dev/ttyUSB0` //! interface. The device binary must *not* be stripped. #![deny(missing_docs)] #![deny(warnings)] #![no_std] /// A logger compatible with the `stlog` logging framework /// /// # Contract /// /// The `log` implementation must simply send its argument as a byte through /// some interface. pub trait Logger { /// Error type of the log operation type Error; /// Logs a string stored in debuginfo with address `addr` fn log(self, addr: u8) -> Result<(), Self::Error>; } #[macro_export] macro_rules! trace { ($logger:expr, $string:expr) => { { #[link_section = ".stlog.trace"] #[export_name = $string] static SYMBOL: bool = false; $crate::Logger::log($logger, &SYMBOL as *const _ as usize as u8) } }; } #[macro_export] macro_rules! debug { ($logger:expr, $string:expr) => { { #[link_section = ".stlog.debug"] #[export_name = $string] static SYMBOL: bool = false; $crate::Logger::log($logger, &SYMBOL as *const _ as usize as u8) } }; } #[macro_export] macro_rules! info { ($logger:expr, $string:expr) => { { #[link_section = ".stlog.info"] #[export_name = $string] static SYMBOL: bool = false; $crate::Logger::log($logger, &SYMBOL as *const _ as usize as u8) } }; } #[macro_export] macro_rules! warn { ($logger:expr, $string:expr) => { { #[link_section = ".stlog.warn"] #[export_name = $string] static SYMBOL: bool = false; $crate::Logger::log($logger, &SYMBOL as *const _ as usize as u8) } }; } #[macro_export] macro_rules! error { ($logger:expr, $string:expr) => { { #[link_section = ".stlog.error"] #[export_name = $string] static SYMBOL: bool = false; $crate::Logger::log($logger, &SYMBOL as *const _ as usize as u8) } }; }