lite-log 0.1.1

//! A logger that prints all messages with a simple, readable output format.
//!
//! Optional features include timestamps, colored output and logging to stderr.
//!
//! ```rust
//! lite_log::LiteLogger::new().env().init().unwrap();
//!
//! log::warn!("This is an example message.");
//! ```
//!
//! Some shortcuts are available for common use cases.
//!
//! Just initialize logging without any configuration:
//!
//! ```rust
//! lite_log::init().unwrap();
//! ```
//!
//! Set the log level from the `RUST_LOG` environment variable:
//!
//! ```rust
//! lite_log::init_with_env().unwrap();
//! ```
//!
//! Hardcode a default log level:
//!
//! ```rust
//! lite_log::init_with_level(log::Level::Warn).unwrap();
//! ```

#![cfg_attr(feature = "nightly", feature(thread_id_value))]

#[cfg(feature = "colored")]
use colored::*;
use log::{Level, LevelFilter, Log, Metadata, Record, SetLoggerError};
use std::{collections::HashMap, str::FromStr};

#[cfg(feature = "timestamps")]
use chrono::{Local, Utc,FixedOffset};

#[cfg(feature = "timestamps")]
const TIMESTAMP_FORMAT_OFFSET: &str = "%Y-%m-%d %H:%M:%S";

#[cfg(feature = "timestamps")]
const TIMESTAMP_FORMAT_UTC: &str = "%Y-%m-%dT%H:%M:%S%.3f %z";

#[cfg(feature = "timestamps")]
#[derive(PartialEq)]
enum Timestamps {
    None,
    Local,
    Utc,
    UtcOffset(i32),
}

/// Implements [`Log`] and a set of simple builder methods for configuration.
///
/// Use the various "builder" methods on this struct to configure the logger,
/// then call [`init`] to configure the [`log`] crate.
pub struct Logger {
    /// The default logging level
    default_level: LevelFilter,

    /// The specific logging level for each module
    ///
    /// This is used to override the default value for some specific modules.
    /// After initialization, the vector is sorted so that the first (prefix) match
    /// directly gives us the desired log level.
    module_levels: Vec<(String, LevelFilter)>,

    /// Whether to include thread names (and IDs) or not
    ///
    /// This field is only available if the `threads` feature is enabled.
    #[cfg(feature = "threads")]
    threads: bool,

    /// Control how timestamps are displayed.
    ///
    /// This field is only available if the `timestamps` feature is enabled.
    #[cfg(feature = "timestamps")]
    timestamps: Timestamps,
    #[cfg(feature = "timestamps")]
    timestamps_format: Option<String>,

    /// Whether to use color output or not.
    ///
    /// This field is only available if the `color` feature is enabled.
    #[cfg(feature = "colored")]
    colors: bool,
}

impl Logger {
    /// Initializes the global logger with a Logger instance with
    /// default log level set to `Level::Trace`.
    ///
    /// ```no_run
    /// use lite_log::LiteLogger as Logger;
    /// Logger::new().env().init().unwrap();
    /// log::warn!("This is an example message.");
    /// ```
    ///
    /// [`init`]: #method.init
    #[must_use = "You must call init() to begin logging"]
    pub fn new() -> Logger {
        Logger {
            default_level: LevelFilter::Trace,
            module_levels: Vec::new(),

            #[cfg(feature = "threads")]
            threads: false,

            #[cfg(feature = "timestamps")]
            timestamps: Timestamps::Utc,

            #[cfg(feature = "timestamps")]
            timestamps_format: None,

            #[cfg(feature = "colored")]
            colors: true,
        }
    }

    /// Simulates env_logger behavior, which enables the user to choose log level by
    /// setting a `RUST_LOG` environment variable. The `RUST_LOG` is not set or its value is not
    /// recognized as one of the log levels, this function will use the `Error` level by default.
    ///
    /// You may use the various builder-style methods on this type to configure
    /// the logger, and you must call [`init`] in order to start logging messages.
    ///
    /// ```no_run
    /// use lite_log::LiteLogger as Logger;
    /// Logger::from_env().init().unwrap();
    /// log::warn!("This is an example message.");
    /// ```
    ///
    /// [`init`]: #method.init
    #[must_use = "You must call init() to begin logging"]
    #[deprecated(
        since = "1.12.0",
        note = "Use [`env`](#method.env) instead. Will be removed in version 2.0.0."
    )]
    pub fn from_env() -> Logger {
        Logger::new().with_level(log::LevelFilter::Error).env()
    }

    /// Simulates env_logger behavior, which enables the user to choose log
    /// level by setting a `RUST_LOG` environment variable. This will use
    /// the default level set by [`with_level`] if `RUST_LOG` is not set or
    /// can't be parsed as a standard log level.
    ///
    /// This must be called after [`with_level`]. If called before
    /// [`with_level`], it will have no effect.
    ///
    /// [`with_level`]: #method.with_level
    #[must_use = "You must call init() to begin logging"]
    pub fn env(mut self) -> Logger {
        self.default_level = std::env::var("RUST_LOG")
            .ok()
            .as_deref()
            .map(log::LevelFilter::from_str)
            .and_then(Result::ok)
            .unwrap_or(self.default_level);

        self
    }

    /// Set the 'default' log level.
    ///
    /// You can override the default level for specific modules and their sub-modules using [`with_module_level`]
    ///
    /// This must be called before [`env`]. If called after [`env`], it will override the value loaded from the environment.
    ///
    /// [`env`]: #method.env
    /// [`with_module_level`]: #method.with_module_level
    #[must_use = "You must call init() to begin logging"]
    pub fn with_level(mut self, level: LevelFilter) -> Logger {
        self.default_level = level;
        self
    }

    /// Override the log level for some specific modules.
    ///
    /// This sets the log level of a specific module and all its sub-modules.
    /// When both the level for a parent module as well as a child module are set,
    /// the more specific value is taken. If the log level for the same module is
    /// specified twice, the resulting log level is implementation defined.
    ///
    /// # Examples
    ///
    /// Silence an overly verbose crate:
    ///
    /// ```no_run
    /// use lite_log::Logger;
    /// use log::LevelFilter;
    ///
    /// Logger::new().with_module_level("chatty_dependency", LevelFilter::Warn).init().unwrap();
    /// ```
    ///
    /// Disable logging for all dependencies:
    ///
    /// ```no_run
    /// use lite_log::Logger;
    /// use log::LevelFilter;
    ///
    /// Logger::new()
    ///     .with_level(LevelFilter::Off)
    ///     .with_module_level("my_crate", LevelFilter::Info)
    ///     .init()
    ///     .unwrap();
    /// ```
    #[must_use = "You must call init() to begin logging"]
    pub fn with_module_level(mut self, target: &str, level: LevelFilter) -> Logger {
        self.module_levels.push((target.to_string(), level));

        /* Normally this is only called in `init` to avoid redundancy, but we can't initialize the logger in tests */
        #[cfg(test)]
        self.module_levels
            .sort_by_key(|(name, _level)| name.len().wrapping_neg());

        self
    }

    /// Override the log level for specific targets.
    #[must_use = "You must call init() to begin logging"]
    #[deprecated(
        since = "1.11.0",
        note = "Use [`with_module_level`](#method.with_module_level) instead. Will be removed in version 2.0.0."
    )]
    pub fn with_target_levels(mut self, target_levels: HashMap<String, LevelFilter>) -> Logger {
        self.module_levels = target_levels.into_iter().collect();

        /* Normally this is only called in `init` to avoid redundancy, but we can't initialize the logger in tests */
        #[cfg(test)]
        self.module_levels
            .sort_by_key(|(name, _level)| name.len().wrapping_neg());

        self
    }

    /// Control whether thread names (and IDs) are printed or not.
    ///
    /// This method is only available if the `threads` feature is enabled.
    /// Thread names are disabled by default.
    #[must_use = "You must call init() to begin logging"]
    #[cfg(feature = "threads")]
    pub fn with_threads(mut self, threads: bool) -> Logger {
        self.threads = threads;
        self
    }

    /// Control the format used for timestamps.
    ///
    /// Without this, a default format is used depending on the timestamps type.
    ///
    /// The syntax for the format can be found in the
    /// [`chrono` crate book](https://docs.rs/chrono/latest/chrono/format/index.html).
    ///
    /// ```
    /// lite_log::LiteLogger::new()
    ///  .with_level(log::LevelFilter::Debug)
    ///  .env()
    ///  .with_timestamp_format(&String::from("%Y-%m-%d %H:%M:%S"))
    ///  .init()
    ///  .unwrap();
    /// ```
    #[must_use = "You must call init() to begin logging"]
    #[cfg(feature = "timestamps")]
    pub fn with_timestamp_format(mut self, format:&String) -> Logger {
        self.timestamps_format = Some(format.clone());
        self
    }

    /// Don't display any timestamps.
    ///
    /// This method is only available if the `timestamps` feature is enabled.
    #[must_use = "You must call init() to begin logging"]
    #[cfg(feature = "timestamps")]
    pub fn without_timestamps(mut self) -> Logger {
        self.timestamps = Timestamps::None;
        self
    }

    /// Display timestamps using the local timezone.
    ///
    /// This method is only available if the `timestamps` feature is enabled.
    #[must_use = "You must call init() to begin logging"]
    #[cfg(feature = "timestamps")]
    pub fn with_local_timestamps(mut self) -> Logger {
        self.timestamps = Timestamps::Local;
        self
    }

    /// Display timestamps using UTC.
    ///
    /// This method is only available if the `timestamps` feature is enabled.
    #[must_use = "You must call init() to begin logging"]
    #[cfg(feature = "timestamps")]
    pub fn with_utc_timestamps(mut self) -> Logger {
        self.timestamps = Timestamps::Utc;
        self
    }

    /// Display timestamps using a static UTC offset.
    ///
    /// This method is only available if the `timestamps` feature is enabled.
    #[must_use = "You must call init() to begin logging"]
    #[cfg(feature = "timestamps")]
    pub fn with_utc_offset(mut self, offset: i32) -> Logger {
        self.timestamps = Timestamps::UtcOffset(offset);
        self
    }

    /// Control whether messages are colored or not.
    ///
    /// This method is only available if the `colored` feature is enabled.
    #[must_use = "You must call init() to begin logging"]
    #[cfg(feature = "colored")]
    pub fn with_colors(mut self, colors: bool) -> Logger {
        self.colors = colors;
        self
    }

    /// 'Init' the actual logger, instantiate it and configure it,
    /// this method MUST be called in order for the logger to be effective.
    pub fn init(mut self) -> Result<(), SetLoggerError> {
        #[cfg(all(windows, feature = "colored"))]
        set_up_color_terminal();

        /* Sort all module levels from most specific to least specific. The length of the module
         * name is used instead of its actual depth to avoid module name parsing.
         */
        self.module_levels
            .sort_by_key(|(name, _level)| name.len().wrapping_neg());
        let max_level = self.module_levels.iter().map(|(_name, level)| level).copied().max();
        let max_level = max_level
            .map(|lvl| lvl.max(self.default_level))
            .unwrap_or(self.default_level);
        log::set_max_level(max_level);
        log::set_boxed_logger(Box::new(self))?;
        Ok(())
    }
}

impl Default for Logger {
    /// See [this](struct.Logger.html#method.new)
    fn default() -> Self {
        Logger::new()
    }
}

impl Log for Logger {
    fn enabled(&self, metadata: &Metadata) -> bool {
        &metadata.level().to_level_filter()
            <= self
                .module_levels
                .iter()
                /* At this point the Vec is already sorted so that we can simply take
                 * the first match
                 */
                .find(|(name, _level)| metadata.target().starts_with(name))
                .map(|(_name, level)| level)
                .unwrap_or(&self.default_level)
    }

    fn log(&self, record: &Record) {
        if self.enabled(record.metadata()) {
            let level_string = {
                #[cfg(feature = "colored")]
                {
                    if self.colors {
                        match record.level() {
                            Level::Error => format!("{:<5}", record.level().to_string()).red().to_string(),
                            Level::Warn => format!("{:<5}", record.level().to_string()).yellow().to_string(),
                            Level::Info => format!("{:<5}", record.level().to_string()).cyan().to_string(),
                            Level::Debug => format!("{:<5}", record.level().to_string()).purple().to_string(),
                            Level::Trace => format!("{:<5}", record.level().to_string()).normal().to_string(),
                        }
                    } else {
                        format!("{:<5}", record.level().to_string())
                    }
                }
                #[cfg(not(feature = "colored"))]
                {
                    format!("{:<5}", record.level().to_string())
                }
            };

            let target = if !record.target().is_empty() {
                record.target()
            } else {
                record.module_path().unwrap_or_default()
            };

            let thread = {
                #[cfg(feature = "threads")]
                if self.threads {
                    let thread = std::thread::current();

                    format!("@{}", {
                        #[cfg(feature = "nightly")]
                        {
                            thread.name().unwrap_or(&thread.id().as_u64().to_string())
                        }

                        #[cfg(not(feature = "nightly"))]
                        {
                            thread.name().unwrap_or("?")
                        }
                    })
                } else {
                    "".to_string()
                }

                #[cfg(not(feature = "threads"))]
                ""
            };

            let timestamp = {
                #[cfg(feature = "timestamps")]
                match self.timestamps {
                    Timestamps::None => "".to_string(),
                    Timestamps::Local => format!( "{} ", Local::now().format(&self.timestamps_format.clone().unwrap_or(String::from(TIMESTAMP_FORMAT_OFFSET)))),
                    Timestamps::Utc => format!("{} ", Utc::now().format(&self.timestamps_format.clone().unwrap_or(String::from(TIMESTAMP_FORMAT_UTC)))),
                    Timestamps::UtcOffset(offset) => {
                        let offset = FixedOffset::east_opt(offset).unwrap();
                        let now_with_offset = Utc::now().with_timezone(&offset);
                        let fmt = self.timestamps_format.clone().unwrap_or(String::from(TIMESTAMP_FORMAT_OFFSET));
                        format!("{} ", now_with_offset.format(&fmt))
                    },
                }

                #[cfg(not(feature = "timestamps"))]
                ""
            };

            let message = format!("{}{} [{}{}] {}", timestamp, level_string, target, thread, record.args());

            #[cfg(not(feature = "stderr"))]
            println!("{}", message);

            #[cfg(feature = "stderr")]
            eprintln!("{}", message);
        }
    }

    fn flush(&self) {}
}

#[cfg(all(windows, feature = "colored"))]
fn set_up_color_terminal() {
    use std::io::{stdout, IsTerminal};

    if stdout().is_terminal() {
        unsafe {
            use windows_sys::Win32::Foundation::INVALID_HANDLE_VALUE;
            use windows_sys::Win32::System::Console::{
                GetConsoleMode, GetStdHandle, SetConsoleMode, CONSOLE_MODE, ENABLE_VIRTUAL_TERMINAL_PROCESSING,
                STD_OUTPUT_HANDLE,
            };

            let stdout = GetStdHandle(STD_OUTPUT_HANDLE);

            if stdout == INVALID_HANDLE_VALUE {
                return;
            }

            let mut mode: CONSOLE_MODE = 0;

            if GetConsoleMode(stdout, &mut mode) == 0 {
                return;
            }

            SetConsoleMode(stdout, mode | ENABLE_VIRTUAL_TERMINAL_PROCESSING);
        }
    }
}

/// Initialise the logger with its default configuration.
///
/// Log messages will not be filtered.
/// The `RUST_LOG` environment variable is not used.
pub fn init() -> Result<(), SetLoggerError> {
    Logger::new().init()
}

/// Initialise the logger with its default configuration.
///
/// Log messages will not be filtered.
/// The `RUST_LOG` environment variable is not used.
///
/// This function is only available if the `timestamps` feature is enabled.
#[cfg(feature = "timestamps")]
pub fn init_utc() -> Result<(), SetLoggerError> {
    Logger::new().with_utc_timestamps().init()
}

/// Initialise the logger with the `RUST_LOG` environment variable.
///
/// Log messages will be filtered based on the `RUST_LOG` environment variable.
pub fn init_with_env() -> Result<(), SetLoggerError> {
    Logger::new().env().init()
}

/// Initialise the logger with a specific log level.
///
/// Log messages below the given [`Level`] will be filtered.
/// The `RUST_LOG` environment variable is not used.
pub fn init_with_level(level: Level) -> Result<(), SetLoggerError> {
    Logger::new().with_level(level.to_level_filter()).init()
}

/// Use [`init_with_env`] instead.
///
/// This does the same as [`init_with_env`] but unwraps the result.
#[deprecated(
    since = "1.12.0",
    note = "Use [`init_with_env`] instead, which does not unwrap the result. Will be removed in version 2.0.0."
)]
pub fn init_by_env() {
    init_with_env().unwrap()
}