1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150

//! Logging utilities.

use lazy_static::lazy_static;
use std::cmp::Ord;
use std::collections::VecDeque;
use std::str::FromStr;
use std::sync::{Mutex, RwLock};

/// Saves all log records in a global deque.
///
/// Uses a `DebugView` to access it.
///
/// # Examples
///
/// Set log levels from env vars
///
/// ```
/// # use cursive_core::*;
/// logger::set_filter_levels_from_env();
/// logger::init();
/// ```
///
/// Set log levels explicitly.
///
/// ```
/// # use cursive_core::*;
/// # use log::LevelFilter;
/// logger::set_internal_filter_level(LevelFilter::Warn);
/// logger::set_external_filter_level(LevelFilter::Debug);
/// logger::init();
/// ```

pub struct CursiveLogger;

lazy_static! {
    /// Circular buffer for logs. Use it to implement [`DebugView`].
    ///
    /// [`DebugView`]: ../views/struct.DebugView.html
    pub static ref LOGS: Mutex<VecDeque<Record>> =
        Mutex::new(VecDeque::with_capacity(1_000));

    // Log filter level for log messages from within cursive
    static ref INT_FILTER_LEVEL: RwLock<log::LevelFilter> = RwLock::new(log::LevelFilter::Trace);
    // Log filter level for log messages from sources outside of cursive
    static ref EXT_FILTER_LEVEL: RwLock<log::LevelFilter> = RwLock::new(log::LevelFilter::Trace);
}

/// Sets the internal log filter level.
pub fn set_internal_filter_level(level: log::LevelFilter) {
    *INT_FILTER_LEVEL.write().unwrap() = level;
}

/// Sets the external log filter level.
pub fn set_external_filter_level(level: log::LevelFilter) {
    *EXT_FILTER_LEVEL.write().unwrap() = level;
}

/// Sets log filter levels based on environment variables `RUST_LOG` and `CURSIVE_LOG`.
/// If `RUST_LOG` is set, then both internal and external log levels are set to match.
/// If `CURSIVE_LOG` is set, then the internal log level is set to match with precedence over
/// `RUST_LOG`.
pub fn set_filter_levels_from_env() {
    if let Ok(rust_log) = std::env::var("RUST_LOG") {
        match log::LevelFilter::from_str(&rust_log) {
            Ok(filter_level) => {
                set_internal_filter_level(filter_level);
                set_external_filter_level(filter_level);
            }
            Err(e) => log::warn!("Could not parse RUST_LOG: {}", e),
        }
    }
    if let Ok(cursive_log) = std::env::var("CURSIVE_LOG") {
        match log::LevelFilter::from_str(&cursive_log) {
            Ok(filter_level) => {
                set_internal_filter_level(filter_level);
            }
            Err(e) => log::warn!("Could not parse CURSIVE_LOG: {}", e),
        }
    }
}

/// A log record.
pub struct Record {
    /// Log level used for this record
    pub level: log::Level,
    /// Time this message was logged
    pub time: time::OffsetDateTime,
    /// Message content
    pub message: String,
}

/// Log a record in cursive's log queue.
pub fn log(record: &log::Record) {
    let mut logs = LOGS.lock().unwrap();
    // TODO: customize the format? Use colors? Save more info?
    if logs.len() == logs.capacity() {
        logs.pop_front();
    }
    logs.push_back(Record {
        level: record.level(),
        message: format!("{}", record.args()),
        time: time::OffsetDateTime::now_local().unwrap_or_else(|_| time::OffsetDateTime::now_utc()),
    });
}

impl log::Log for CursiveLogger {
    fn enabled(&self, metadata: &log::Metadata) -> bool {
        if metadata.target().starts_with("cursive_core::") {
            metadata.level() <= *INT_FILTER_LEVEL.read().unwrap()
        } else {
            metadata.level() <= *EXT_FILTER_LEVEL.read().unwrap()
        }
    }

    fn log(&self, record: &log::Record) {
        if self.enabled(record.metadata()) {
            log(record);
        }
    }

    fn flush(&self) {}
}

/// Initialize the Cursive logger.
///
/// Make sure this is the only logger your are using.
///
/// Use a [`DebugView`](crate::views::DebugView) to see the logs, or use
/// [`Cursive::toggle_debug_console()`](crate::Cursive::toggle_debug_console()).
pub fn init() {
    log::set_max_level((*INT_FILTER_LEVEL.read().unwrap()).max(*EXT_FILTER_LEVEL.read().unwrap()));
    // This will panic if `set_logger` was already called.
    log::set_logger(&CursiveLogger).unwrap();
}

/// Return a logger that stores records in cursive's log queue.
///
/// These logs can then be read by a [`DebugView`](crate::views::DebugView).
///
/// An easier alternative might be to use [`init()`].
pub fn get_logger() -> CursiveLogger {
    CursiveLogger
}

/// Adds `n` more entries to cursive's log queue.
///
/// Most of the time you don't need to use this directly.
pub fn reserve_logs(n: usize) {
    LOGS.lock().unwrap().reserve(n);
}