This commit adds an ability to "ref" or "unref" pending ops.
Up to this point Deno had a notion of "async ops" and "unref async ops";
the former keep event loop alive, while the latter do not block event loop
from finishing. It was not possible to change between op types after
dispatching, one had to decide which type to use before dispatch.
Instead of storing ops in two separate "FuturesUnordered" collections,
now ops are stored in a single collection, with supplemental "HashSet"
storing ids of promises that were "unrefed".
Two APIs were added to "Deno.core":
"Deno.core.refOp(promiseId)" which allows to mark promise id
to be "refed" and keep event loop alive (the default behavior)
"Deno.core.unrefOp(promiseId)" which allows to mark promise
id as "unrefed" which won't block event loop from exiting
This allows resources to be "streams" by implementing read/write/shutdown. These streams are implicit since their nature (read/write/duplex) isn't known until called, but we could easily add another method to explicitly tag resources as streams.
`op_read/op_write/op_shutdown` are now builtin ops provided by `deno_core`
Note: this current implementation is simple & straightforward but it results in an additional alloc per read/write call
Closes #12556
This adds `.code` attributes to errors returned by the op-layer, facilitating classifying OS errors and helping node-compat.
Similar to Node, these `.code` attributes are stringified names of unix ERRNOs, the mapping tables are generated by [tools/codegen_error_codes.js](https://gist.github.com/AaronO/dfa1106cc6c7e2a6ebe4dba9d5248858) and derived from libuv and rust's std internals
This commit introduces primordials to deno_core. Primordials are a
frozen set of all intrinsic objects in the runtime. They are not
vulnerable to prototype pollution.
