rust/src/libstd/uv_hl.rs

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#[doc = "
High-level bindings to work with the libuv library.
This module is geared towards library developers who want to
provide a high-level, abstracted interface to some set of
libuv functionality.
"];
export high_level_loop, high_level_msg;
export run_high_level_loop, interact, ref_handle, unref_handle;
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import ll = uv_ll;
#[doc = "
Used to abstract-away direct interaction with a libuv loop.
# Arguments
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* async_handle - a pointer to a pointer to a uv_async_t struct used to 'poke'
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the C uv loop to process any pending callbacks
* op_chan - a channel used to send function callbacks to be processed
by the C uv loop
"]
type high_level_loop = {
async_handle: **ll::uv_async_t,
op_chan: comm::chan<high_level_msg>
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};
#[doc="
Represents the range of interactions with a `high_level_loop`
"]
enum high_level_msg {
interaction (fn~(*libc::c_void)),
auto_ref_handle (*libc::c_void),
auto_unref_handle (*libc::c_void, *u8),
tear_down
}
#[doc = "
Given a vanilla `uv_loop_t*`
# Arguments
* loop_ptr - a pointer to a currently unused libuv loop. Its `data` field
will be overwritten before the loop begins
must be a pointer to a clean rust `uv_async_t` record
* msg_po - an active port that receives `high_level_msg`s
* before_run - a unique closure that is invoked after `uv_async_init` is
called on the `async_handle` passed into this callback, just before `uv_run`
is called on the provided `loop_ptr`
* before_msg_drain - a unique closure that is invoked every time the loop is
awoken, but before the port pointed to in the `msg_po` argument is drained
* before_tear_down - called just before the loop invokes `uv_close()` on the
provided `async_handle`. `uv_run` should return shortly after
"]
unsafe fn run_high_level_loop(loop_ptr: *libc::c_void,
msg_po: comm::port<high_level_msg>,
before_run: fn~(*ll::uv_async_t),
before_msg_drain: fn~(*ll::uv_async_t) -> bool,
before_tear_down: fn~(*ll::uv_async_t)) {
// set up the special async handle we'll use to allow multi-task
// communication with this loop
let async = ll::async_t();
let async_handle = ptr::addr_of(async);
// associate the async handle with the loop
ll::async_init(loop_ptr, async_handle, high_level_wake_up_cb);
// initialize our loop data and store it in the loop
let data: global_loop_data = default_gl_data({
async_handle: async_handle,
mut active: true,
before_msg_drain: before_msg_drain,
before_tear_down: before_tear_down,
msg_po_ptr: ptr::addr_of(msg_po),
mut refd_handles: [mut],
mut unrefd_handles: [mut]
});
let data_ptr = ptr::addr_of(data);
ll::set_data_for_uv_handle(async_handle, data_ptr);
// call before_run
before_run(async_handle);
log(debug, "about to run high level loop");
// enter the loop... this blocks until the loop is done..
ll::run(loop_ptr);
log(debug, "high-level loop ended");
}
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#[doc = "
Provide a callback to be processed by `a_loop`
The primary way to do operations again a running `high_level_loop` that
doesn't involve creating a uv handle via `safe_handle`
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# Arguments
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* a_loop - a `high_level_loop` that you want to do operations against
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* cb - a function callback to be processed on the running loop's
thread. The only parameter is an opaque pointer to the running
uv_loop_t. In the context of this callback, it is safe to use this pointer
to do various uv_* API calls. _DO NOT_ send this pointer out via ports/chans
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"]
unsafe fn interact(a_loop: high_level_loop,
-cb: fn~(*libc::c_void)) {
send_high_level_msg(a_loop, interaction(cb));
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}
iface uv_handle_manager<T> {
fn init() -> T;
}
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type safe_handle_fields<T> = {
hl_loop: high_level_loop,
handle: T,
close_cb: *u8
};
/*fn safe_handle<T>(a_loop: high_level_loop,
handle_val: T,
handle_init_cb: fn~(*libc::c_void, *T),
close_cb: *u8) {
resource safe_handle_container<T>(handle_fields: safe_handle_fields<T>) {
}
}*/
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#[doc="
Needs to be encapsulated within `safe_handle`
"]
fn ref_handle<T>(hl_loop: high_level_loop, handle: *T) unsafe {
send_high_level_msg(hl_loop, auto_ref_handle(handle as *libc::c_void));
}
#[doc="
Needs to be encapsulated within `safe_handle`
"]
fn unref_handle<T>(hl_loop: high_level_loop, handle: *T,
user_close_cb: *u8) unsafe {
send_high_level_msg(hl_loop, auto_unref_handle(handle as *libc::c_void,
user_close_cb));
}
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// INTERNAL API
// data that lives for the lifetime of the high-evel oo
enum global_loop_data {
default_gl_data({
async_handle: *ll::uv_async_t,
mut active: bool,
before_msg_drain: fn~(*ll::uv_async_t) -> bool,
before_tear_down: fn~(*ll::uv_async_t),
msg_po_ptr: *comm::port<high_level_msg>,
mut refd_handles: [mut *libc::c_void],
mut unrefd_handles: [mut *libc::c_void]})
}
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unsafe fn send_high_level_msg(hl_loop: high_level_loop,
-msg: high_level_msg) unsafe {
comm::send(hl_loop.op_chan, msg);
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// if the global async handle == 0, then that means
// the loop isn't active, so we don't need to wake it up,
// (the loop's enclosing task should be blocking on a message
// receive on this port)
if (*(hl_loop.async_handle) != 0 as *ll::uv_async_t) {
log(debug,"global async handle != 0, waking up loop..");
ll::async_send(*(hl_loop.async_handle));
}
else {
log(debug,"GLOBAL ASYNC handle == 0");
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}
}
// this will be invoked by a call to uv::hl::interact() with
// the high_level_loop corresponding to this async_handle. We
// simply check if the loop is active and, if so, invoke the
// user-supplied on_wake callback that is stored in the loop's
// data member
crust fn high_level_wake_up_cb(async_handle: *ll::uv_async_t,
status: int) unsafe {
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// nothing here, yet.
log(debug, #fmt("high_level_wake_up_cb crust.. handle: %? status: %?",
async_handle, status));
let loop_ptr = ll::get_loop_for_uv_handle(async_handle);
let data = ll::get_data_for_uv_handle(async_handle) as *global_loop_data;
// we check to see if the loop is "active" (the loop is set to
// active = false the first time we realize we need to 'tear down',
// set subsequent calls to the global async handle may be triggered
// before all of the uv_close() calls are processed and loop exits
// on its own. So if the loop isn't active, we won't run the user's
// on_wake callback (and, consequently, let messages pile up, probably
// in the loops msg_po)
if (*data).active {
log(debug, "before on_wake");
let mut do_msg_drain = (*data).before_msg_drain(async_handle);
let mut continue = true;
if do_msg_drain {
let msg_po = *((*data).msg_po_ptr);
if comm::peek(msg_po) {
// if this is true, we'll iterate over the
// msgs waiting in msg_po until there's no more
log(debug,"got msg_po");
while(continue) {
log(debug,"before alt'ing on high_level_msg");
alt comm::recv(msg_po) {
interaction(cb) {
log(debug,"got interaction, before cb..");
// call it..
cb(loop_ptr);
log(debug,"after calling cb");
}
auto_ref_handle(handle) {
high_level_ref(data, handle);
}
auto_unref_handle(handle, user_close_cb) {
high_level_unref(data, handle, false, user_close_cb);
}
tear_down {
log(debug,"incoming hl_msg: got tear_down");
}
}
continue = comm::peek(msg_po);
}
}
}
log(debug, #fmt("after on_wake, continue? %?", continue));
if !do_msg_drain {
high_level_tear_down(data);
}
}
}
crust fn tear_down_close_cb(handle: *ll::uv_async_t) unsafe {
log(debug, #fmt("tear_down_close_cb called, closing handle at %?",
handle));
// TODO: iterate through open handles on the loop and uv_close()
// them all
//let data = ll::get_data_for_uv_handle(handle) as *global_loop_data;
}
fn high_level_tear_down(data: *global_loop_data) unsafe {
log(debug, "high_level_tear_down() called, close async_handle");
// call user-suppled before_tear_down cb
let async_handle = (*data).async_handle;
(*data).before_tear_down(async_handle);
ll::close(async_handle as *libc::c_void, tear_down_close_cb);
}
unsafe fn high_level_ref(data: *global_loop_data, handle: *libc::c_void) {
log(debug,"incoming hl_msg: got auto_ref_handle");
let mut refd_handles = (*data).refd_handles;
let handle_already_refd = refd_handles.contains(handle);
if handle_already_refd {
fail "attempt to do a high-level ref an already ref'd handle";
}
refd_handles += [handle];
(*data).refd_handles = refd_handles;
}
unsafe fn high_level_unref(data: *global_loop_data, handle: *libc::c_void,
manual_unref: bool, user_close_cb: *u8) {
log(debug,"incoming hl_msg: got auto_unref_handle");
let mut refd_handles = (*data).refd_handles;
let mut unrefd_handles = (*data).unrefd_handles;
let handle_already_refd = refd_handles.contains(handle);
if !handle_already_refd {
fail "attempting to high-level unref an untracked handle";
}
let double_unref = unrefd_handles.contains(handle);
if double_unref {
if manual_unref {
// will allow a user to manual unref, but only signal
// a fail when a double-unref is caused by a user
fail "attempting to high-level unref an unrefd handle";
}
}
else {
ll::close(handle, user_close_cb);
let last_idx = vec::len(refd_handles) - 1u;
let handle_idx = vec::position_elem(refd_handles, handle);
alt handle_idx {
none {
fail "trying to remove handle that isn't in refd_handles";
}
some(idx) {
refd_handles[idx] <-> refd_handles[last_idx];
vec::pop(refd_handles);
}
}
(*data).refd_handles = refd_handles;
unrefd_handles += [handle];
(*data).unrefd_handles = unrefd_handles;
if vec::len(refd_handles) == 0u {
log(debug, "0 referenced handles, start loop teardown");
high_level_tear_down(data);
}
else {
log(debug, "more than 0 referenced handles");
}
}
}