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// (c) 2018 Tuan Tran. Licensed under MIT License.
/*!
**NOTICE: THE LIBRARY IS STILL EXPERIMENTAL AND VERY BUGGY. API IS INCOMPLETE AND SUBJECTED TO CHANGE. PLEASE PROCEED WITH CAUTION**
This crate is an implementation of ObjectSpace - a natural progression on the idea of [TupleSpace](https://en.wikipedia.org/wiki/Tuple_space) proposed by Gelernter in 1985. ObjectSpace is a data structure with the capability of holding any structure (e.g: a string, an int, and a complex struct could all lives under one ObjectSpace). It also allows retrieving a struct based on the value of a field.
This crate also provides a fully thread-safe implementation of ObjectSpace, which allows simple concurrent and distributed programming.
# API
An ObjectSpace could perform the following tasks:
- `write` an object to the space. E.g: `space.write(test_struct)`
- `try_read` (non-blocking), `read` (blocking), and `read_all` structs of a type. E.g: `space.try_read::<TestStruct>()`
- `try_take`, `take`, and `take_all` to remove and returns struct of a type. E.g: `space.try_take::<TestStruct>()`
Notice that an ObjectSpace could hold data from any types, which means that an i64, a String, and a complex struct could all live under one space (which leads to the somewhat wordy API for retrieving items).
Additionally, by implementing `ValueLookupObjectSpace` and `RangeLookupObjectSpace`, an ObjectSpace could retrieve item based on the value of a field. Notice that the field must be a "basic" field: the type of the field must be either an int, a string, or a bool.
E.g: Given a TestStruct:
```rust
struct Prop {
touched: bool
}
struct TestStruct {
index: i32,
property: Prop,
}
```
`space.try_take_by_value::<TestStruct>("property.touched", true)` will return a `TestStruct` with the value `true` for `property.touched`. `space.try_take_by_range::<TestStruct>("index", 2..10)` will return a `TestStruct` with the value of `index` between in the range `2..10`
For further information, please read the documentation of `ObjectSpace`, `RangeLookupObjectSpace`, and `ValueLookupObjectSpace`
# TreeObjectSpace
`TreeSpaceObject` is a referenced implementation of `ObjectSpace` trait. It is, in essence, a concurrent HashMap of `TypeId` and corresponding `Entry` for each type. Each `Entry` stores objects by serializing & flattening their structure, then put the values of basic fields in a `BTreeMap` for efficient lookup. `TreeSpaceObject` is thread-safe, which allows it to be used in concurrent and distributed settings.
# Example
Here is a program to calculate all primes up to a limit using ObjectSpace
```rust
extern crate object_space;
extern crate serde;
#[macro_use]
extern crate serde_derive;
use std::thread;
use std::env;
use std::sync::Arc;
use object_space::{ObjectSpace, ValueLookupObjectSpace, RangeLookupObjectSpace, TreeObjectSpace};
fn main() {
let mut args = env::args();
let upper_lim = 1000000;
let thread_count = 4;
// setup. add 2 & 3 just because we can
let mut n = 4;
let space = Arc::new(TreeObjectSpace::new());
space.write::<i64>(2);
space.write::<i64>(3);
// create 4 worker threads
for _ in 0..thread_count {
let space_clone = space.clone();
thread::spawn(move || {
check_numbers(space_clone);
});
}
// continue until we hit limit
while n < upper_lim {
let max = if n * n < upper_lim { n * n } else { upper_lim };
for i in 0..thread_count {
// divide work evenly between threads
let start =
n + (((max - n) as f64) / (thread_count as f64) * (i as f64)).round() as i64;
let end =
n + (((max - n) as f64) / (thread_count as f64) * ((i + 1) as f64)).round() as i64;
let clone = space.clone();
clone.write(Task {
finished: false,
start: start,
end: end,
});
}
// "joining" threads
for _ in 0..thread_count {
let clone = space.clone();
clone.take_by_value::<Task>("finished", &true);
}
n = max;
}
}
fn check_numbers(space: Arc<TreeObjectSpace>) {
loop {
let task = space.take_by_value::<Task>("finished", &false);
let max = task.end;
let min = task.start;
let primes: Vec<i64> = space.read_all::<i64>().filter(|i| i * i < max).collect();
for i in min..max {
if primes.iter().all(|prime| i % prime != 0) {
space.write(i);
}
}
space.write(Task {
finished: true,
start: min,
end: max,
});
}
}
#[derive(Serialize, Deserialize)]
struct Task {
finished: bool,
start: i64,
end: i64,
}
```
*/
extern crate chashmap;
extern crate indexmap;
extern crate ordered_float;
extern crate serde;
extern crate serde_derive;
extern crate serde_json;
pub use *;