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

use std::env;
use std::error::Error;
use std::fs::{self, File};
use std::path::PathBuf;
use std::io::{BufWriter, Read, Write};

use bincode::{self, Infinite};
use memmap::Mmap;
use serde::Serialize;
use serde::de::DeserializeOwned;

lazy_static! {
    static ref TERRA_DIRECTORY: PathBuf = {
        env::home_dir().unwrap_or(PathBuf::from(".")).join(".terra")
    };
}

pub trait WebAsset {
    type Type;

    fn url(&self) -> String;
    fn filename(&self) -> String;
    fn parse(&self, data: Vec<u8>) -> Result<Self::Type, Box<Error>>;

    fn credentials(&self) -> Option<(String, String)> {
        None
    }

    fn load(&self) -> Result<Self::Type, Box<Error>> {
        let filename = TERRA_DIRECTORY.join(self.filename());

        let try_cached = || {
            let mut file = File::open(&filename)?;
            let mut data = Vec::<u8>::new();
            file.read_to_end(&mut data)?;
            self.parse(data)
        };
        if let Ok(asset) = try_cached() {
            return Ok(asset);
        }

        let mut data = Vec::<u8>::new();
        {
            use curl::easy::Easy;
            let mut easy = Easy::new();
            easy.url(&self.url())?;
            easy.follow_location(true)?;
            easy.progress(true)?;
            if let Some((username, password)) = self.credentials() {
                easy.cookie_file("")?;
                easy.unrestricted_auth(true)?;
                easy.username(&username)?;
                easy.password(&password)?;
            }
            let mut easy = easy.transfer();
            easy.write_function(|d| {
                let len = d.len();
                data.extend(d);
                Ok(len)
            })?;
            easy.perform()?;
        }

        if let Some(parent) = filename.parent() {
            fs::create_dir_all(parent)?;
        }
        let mut file = File::create(&filename)?;
        file.write_all(&data)?;
        file.sync_all()?;
        Ok(self.parse(data)?)
    }
}

pub trait GeneratedAsset {
    type Type: Serialize + DeserializeOwned;

    fn filename(&self) -> String;
    fn generate(&self) -> Result<Self::Type, Box<Error>>;

    fn load(&self) -> Result<Self::Type, Box<Error>> {
        let filename = TERRA_DIRECTORY.join(self.filename());
        if let Ok(mut file) = File::open(&filename) {
            let mut contents = Vec::new();
            file.read_to_end(&mut contents)?;
            Ok(bincode::deserialize(&contents)?)
        } else {
            let generated = self.generate()?;
            if let Some(parent) = filename.parent() {
                fs::create_dir_all(parent)?;
            }
            let mut file = File::create(&filename)?;
            {
                let mut writer = BufWriter::new(&mut file);
                bincode::serialize_into(&mut writer, &generated, Infinite)?;
            }
            file.sync_all()?;
            Ok(generated)
        }
    }
}

pub(crate) trait MMappedAsset {
    type Header: Serialize + DeserializeOwned;

    fn filename(&self) -> String;
    fn generate<W: Write>(&self, w: W) -> Result<Self::Header, Box<Error>>;

    fn load(&self) -> Result<(Self::Header, Mmap), Box<Error>> {
        let header_filename = TERRA_DIRECTORY.join(self.filename() + ".hdr");
        let data_filename = TERRA_DIRECTORY.join(self.filename() + ".data");

        if let (Ok(mut header), Ok(data)) =
            (File::open(&header_filename), File::open(&data_filename))
        {
            let mut contents = Vec::new();
            header.read_to_end(&mut contents)?;
            let header = bincode::deserialize(&contents)?;
            let mapping = Mmap::open(&data, ::memmap::Protection::Read)?;
            Ok((header, mapping))
        } else {
            if let Some(parent) = data_filename.parent() {
                fs::create_dir_all(parent)?;
            }
            let mut data_file = File::create(&data_filename)?;
            let header = self.generate(BufWriter::new(&mut data_file))?;
            data_file.sync_all()?;

            let mut header_file = File::create(&header_filename)?;
            {
                let mut writer = BufWriter::new(&mut header_file);
                bincode::serialize_into(&mut writer, &header, Infinite)?;
            }
            header_file.sync_all()?;

            // Open for reading this time
            let data_file = File::open(&data_filename)?;
            let mapping = Mmap::open(&data_file, ::memmap::Protection::Read)?;
            Ok((header, mapping))
        }
    }
}