Fail gracefully when memory limit reached

[ateucher]

This is related to #33. I understand that it might be difficult to increase the available memory to a v8 context, but is there a way to fail gracefully when that limit is (expected to be) reached? Currently R aborts:

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Attaching package: 'testthat'

The following objects are masked from 'package:devtools':

    setup, test_file

> library(V8)
Using V8 engine 7.2.502.24
> ctx <- v8()
> foo <- matrix(seq(100000000), 100000)
> ctx$assign("foo", foo)

<--- Last few GCs --->
ti[44963:0x10e1cf000]   233285 ms: Mark-sweep 1401.7 (1407.2) -> 1401.7 (1408.2) MB, 56.0 / 0.0 ms  (+ 19.4 ms in 16 steps since start of marking, biggest step 19.1 ms, walltime since start of marking 78 ms) (average mu = 0.217, current mu = 0.125) allocati[44963:0x10e1cf000]   233364 ms: Mark-sweep 1403.0 (1408.2) -> 1403.0 (1409.7) MB, 27.7 / 0.0 ms  (+ 48.0 ms in 20 steps since start of marking, biggest step 13.3 ms, walltime since start of marking 79 ms) (average mu = 0.183, current mu = 0.145) allocati

<--- JS stacktrace --->


#
# Fatal javascript OOM in Ineffective mark-compacts near heap limit
#


 *** caught illegal operation ***
address 0x111a1f612, cause 'illegal opcode'

Traceback:
 1: context_eval(join(src), private$context)
 2: get_str_output(context_eval(join(src), private$context))
 3: this$eval(paste("var", name, "=", toJSON(value, auto_unbox = auto_unbox,     ...)))
 4: ctx$assign("foo", foo)

Possible actions:
1: abort (with core dump, if enabled)
2: normal R exit
3: exit R without saving workspace
4: exit R saving workspace
Selection: 1
R is aborting now ...
Illegal instruction: 4

I've had a hard time trying to figure out how large an R object will be once it's been serialized into JSON in a V8 environment. Any suggestions?

Thanks!