# Package jail
--

    import "github.com/status-im/status-go/geth/jail"
    
[![GoDoc](https://godoc.org/github.com/status-im/status-go/geth/jail?status.svg)](https://godoc.org/github.com/status-im/status-go/geth/jail)

Package jail implements "jailed" enviroment for executing arbitrary JavaScript
code using Otto JS interpreter (https://github.com/robertkrimen/otto).

Jail create multiple JailCells, one cell per status client chat. Each cell runs
own Otto virtual machine and lives forever, but that may change in the future.

    +----------------------------------------------+
    |                     Jail                     |
    +----------------------------------------------+
    +---------+ +---------+ +---------+  +---------+
    |  Cell   | |  Cell   | |  Cell   |  |  Cell   |
    |ChatID 1 | |ChatID 2 | |ChatID 3 |  |ChatID N |
    |+-------+| |+-------+| |+-------+|  |+-------+|
    ||Otto VM|| ||Otto VM|| ||Otto VM||  ||Otto VM||
    |+-------+| |+-------+| |+-------+|  |+-------+|
    || Loop  || || Loop  || || Loop  ||  || Loop  ||
    ++-------++ ++-------++ ++-------++  ++-------++


# Get and Set

(*JailCell).Get/Set functions provide transparent and concurrently safe wrappers
for Otto VM Get and Set functions respectively. See Otto documentation for usage
examples: https://godoc.org/github.com/robertkrimen/otto


# Call and Run

(*JailCell).Call/Run functions allows executing arbitrary JS in the cell.
They're also wrappers arount Otto VM functions of the same name. Run accepts raw
JS strings for execution, Call takes a JS function name (defined in VM) and
parameters.


# Timeouts and intervals support

Default Otto VM interpreter doesn't support setTimeout()/setInterval() JS
functions, because they're not part of ECMA-262 spec, but properties of the
window object in browser. We add support for them using
http://github.com/deoxxa/ottoext/timers and
http://github.com/deoxxa/ottoext/loop packages.

Each cell starts a new loop in a separate goroutine, registers functions for
setTimeout/setInterval calls and associate them with this loop. All JS code
executed as callback to setTimeout/setInterval will be handled by this loop.

For example, following code:

    cell.Run(`setTimeout(function(){ value = "42" }, 2000);`)

will execute setTimeout and return immidiately, but callback function will be
executed after 2 seconds in the loop that was started upon current cell.

In order to capture response one may use following approach:

    err = cell.Set("__captureResponse", func(val string) otto.Value {
    	fmt.Println("Captured response from callback:", val)
    	return otto.UndefinedValue()
    })
    cell.Run(`setTimeout(function(){ __captureResponse("OK") }, 2000);`)


# Fetch support

### TBD