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use std::collections::HashMap;
use std::ptr;
use std::io::{self, BufRead, BufReader};
use std::fs::{File, OpenOptions};
use libc;
use serde_json::{to_string, to_value};
use json::JsonName;
use collection::{start};
use error::{Error, ErrorEnum};
use {Name, Value, Visitor, Collection, ActiveCollection};
#[cfg(windows)]
pub fn start_with_reading<'x, T: Collection + ?Sized>(coll: &'x T)
-> Result<ActiveCollection<'x>, Error>
{
start(coll)
}
#[cfg(unix)]
pub fn start_with_reading<'x, T: Collection + ?Sized>(coll: &'x T)
-> Result<ActiveCollection<'x>, Error>
{
match read_and_map(coll) {
Ok(Some(x)) => Ok(x),
Ok(None) => start(coll),
Err(e) => {
warn!("Error reading old metrics: {}. \
Trying to create new files...", e);
start(coll)
}
}
}
#[cfg(unix)]
fn read_and_map<'x, T: Collection + ?Sized>(coll: &'x T)
-> Result<Option<ActiveCollection<'x>>, Error>
{
use std::os::unix::io::AsRawFd;
use collection::path_from_env;
let (dir, name) = path_from_env(false);
let values_path = dir.join(format!("{}.values", name));
let meta_path = dir.join(format!("{}.meta", name));
let meta_file = match File::open(&meta_path) {
Ok(file) => file,
Err(e) => {
if e.kind() != io::ErrorKind::NotFound {
return Err(ErrorEnum::Read(meta_path, e).into());
}
return Ok(None);
}
};
let mut options = OpenOptions::new();
options.read(true).write(true).create(false).truncate(false);
let values_file = match options.open(&values_path) {
Ok(file) => file,
Err(e) => {
if e.kind() != io::ErrorKind::NotFound {
return Err(ErrorEnum::Read(values_path, e).into());
}
return Ok(None);
}
};
let values_size = values_file.metadata()
.map_err(|e| ErrorEnum::Read(meta_path.clone(), e))?
.len() as usize;
let ptr = unsafe {
libc::mmap(ptr::null_mut(), values_size,
libc::PROT_READ | libc::PROT_WRITE,
libc::MAP_SHARED,
values_file.as_raw_fd(),
0)
};
if ptr == libc::MAP_FAILED {
let err = io::Error::last_os_error();
return Err(ErrorEnum::Mmap(values_path, err, values_size).into());
}
let mut result = ActiveCollection {
meta_path: meta_path.clone(),
values_path: values_path,
metrics: Vec::new(),
mmap: ptr,
mmap_size: values_size,
};
struct MapVisitor<'a, 'b: 'a>(&'a mut HashMap<String, &'b Value>);
impl<'a, 'b: 'a> Visitor<'b> for MapVisitor<'a, 'b> {
fn metric(&mut self, name: &Name, value: &'b Value)
{
self.0.insert(to_string(&to_value(JsonName(name))
.expect("can always serialize"))
.expect("can always serialize"),
value);
}
}
let mut map = HashMap::new();
coll.visit(&mut MapVisitor(&mut map));
let mut extra = 0;
let mut wrong_type = 0;
let mut offset = 0;
for line in BufReader::new(meta_file).lines() {
let line = line.map_err(|e| ErrorEnum::Read(meta_path.clone(), e))?;
let mut pair = line.splitn(2, ":");
let mut type_iter = pair.next().unwrap().split(' ');
let kind = type_iter.next().unwrap();
let size: isize = type_iter.next()
.ok_or_else(|| ErrorEnum::InvalidMeta(
meta_path.clone(), "Unsized type"))?
.parse().map_err(|_| ErrorEnum::InvalidMeta(
meta_path.clone(), "Can't parse type size"))?;
let suffix = type_iter.next();
if (offset + size) as usize > values_size {
return Err(ErrorEnum::InvalidMeta(
meta_path.clone(), "Offset is out of range").into());
}
if kind == "pad" {
offset += size;
continue;
}
let name = pair.next()
.ok_or_else(|| ErrorEnum::InvalidMeta(meta_path.clone(),
"No description for value"))?
.trim();
if let Some(metric) = map.remove(name) {
let typ = metric.raw_type();
if kind != typ.main_type() || suffix != typ.type_suffix() {
wrong_type += 1;
} else {
unsafe {
metric.assign(ptr.offset(offset));
result.metrics.push(metric);
}
}
} else {
extra += 1;
}
offset += size;
}
if extra > 0 || map.len() > 0 {
debug!("Found {} extra metrics, {} metrics are not present, \
{} have different type. \
Copying metrics and overriding file.",
extra, map.len(), wrong_type);
return Ok(None)
} else {
debug!("Continuing with {} metrics and {}/{} bytes",
result.metrics.len(), offset, values_size);
}
Ok(Some(result))
}