This is a back-port of 4abad23, whichi is supposed to fix
joyent/node#4809.
The private `original_console_mode` field in the uv_tty_t struct has
been renamed, but couldn't be removed because changing the ABI isn't
allowed on stable branches.
In very rare circumstances a uv_read_start() call on a uv_tty_t handle
in raw mode would return -1 but there was no actual failure. This patch
fixes that.
This commit changes how the event loop determines if it needs to stay alive.
Previously, an internal counter was increased whenever a handle got created
and decreased again when the handle was closed.
While conceptually simple, it turned out hard to work with: you often want
to keep the event loop alive only if the handle is actually doing something.
Stopped or inactive handles were a frequent source of hanging event loops.
That's why this commit changes the reference counting scheme to a model where
a handle only references the event loop when it's active. 'Active' means
different things for different handle types, e.g.:
* timers: ticking
* sockets: reading, writing or listening
* processes: always active (for now, subject to change)
* idle, check, prepare: only active when started
This commit also changes how the uv_ref() and uv_unref() functions work: they
now operate on the level of individual handles, not the whole event loop.
The Windows implementation was done by Bert Belder.
This patch changes how uv-win uses the UV_SHUTTING and UV_SHUT flags.
UV_SHUT is now only used for tcp handles to track whether shutdown() has
actually been called. UV_SHUTTING has the more generic meaning of
"no longer readable". It would be good to replace it by an actual
UV_READABLE flag in the future.
This makes the shutdown_close_tcp and shutdown_close_pipe tests pass on
windows.
