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task.rs remove old builder interface
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@bblum
bblum committed Jul 24, 2012
1 parent be3a71a commit c0abe69
Showing 1 changed file with 59 additions and 191 deletions.
250 changes: 59 additions & 191 deletions src/libcore/task.rs
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Original file line number Diff line number Diff line change
Expand Up @@ -34,7 +34,6 @@ export notification;
export sched_mode;
export sched_opts;
export task_opts;
export builder;
export task_builder;

export default_task_opts;
Expand Down Expand Up @@ -184,14 +183,6 @@ type task_opts = {
// when you try to reuse the builder to spawn a new task. We'll just
// sidestep that whole issue by making builders uncopyable and making
// the run function move them in.
enum builder {
builder_({
mut opts: task_opts,
mut gen_body: fn@(+fn~()) -> fn~(),
can_not_copy: option<comm::port<()>>
})
}

class dummy { let x: (); new() { self.x = (); } drop { } }

// FIXME (#2585): Replace the 'consumed' bit with move mode on self
Expand Down Expand Up @@ -262,8 +253,26 @@ impl task_builder for task_builder {
})
}

/// Configure a future result notification for this task.
/**
* Get a future representing the exit status of the task.
*
* Taking the value of the future will block until the child task
* terminates. The future-receiving callback specified will be called
* *before* the task is spawned; as such, do not invoke .get() within the
* closure; rather, store it in an outer variable/list for later use.
*
* Note that the future returning by this function is only useful for
* obtaining the value of the next task to be spawning with the
* builder. If additional tasks are spawned with the same builder
* then a new result future must be obtained prior to spawning each
* task.
*/
fn future_result(blk: fn(-future::future<task_result>)) -> task_builder {
// FIXME (#1087, #1857): Once linked failure and notification are
// handled in the library, I can imagine implementing this by just
// registering an arbitrary number of task::on_exit handlers and
// sending out messages.

// Construct the future and give it to the caller.
let po = comm::port::<notification>();
let ch = comm::chan(po);
Expand All @@ -290,6 +299,19 @@ impl task_builder for task_builder {
with *self.consume()
})
}

/**
* Add a wrapper to the body of the spawned task.
*
* Before the task is spawned it is passed through a 'body generator'
* function that may perform local setup operations as well as wrap
* the task body in remote setup operations. With this the behavior
* of tasks can be extended in simple ways.
*
* This function augments the current body generator with a new body
* generator by applying the task body which results from the
* existing body generator to the new body generator.
*/
fn add_wrapper(wrapper: fn@(+fn~()) -> fn~()) -> task_builder {
let prev_gen_body = self.gen_body;
task_builder({
Expand All @@ -299,7 +321,18 @@ impl task_builder for task_builder {
})
}

/// Run the task.
/**
* Creates and exucutes a new child task
*
* Sets up a new task with its own call stack and schedules it to run
* the provided unique closure. The task has the properties and behavior
* specified by the task_builder.
*
* # Failure
*
* When spawning into a new scheduler, the number of threads requested
* must be greater than zero.
*/
fn spawn(+f: fn~()) {
let x = self.consume();
spawn_raw(x.opts, x.gen_body(f));
Expand All @@ -313,7 +346,18 @@ impl task_builder for task_builder {
f(option::unwrap(my_arg))
}
}
/// Runs a task with a listening port, returning the associated channel.

/**
* Runs a new task while providing a channel from the parent to the child
*
* Sets up a communication channel from the current task to the new
* child task, passes the port to child's body, and returns a channel
* linked to the port to the parent.
*
* This encapsulates some boilerplate handshaking logic that would
* otherwise be required to establish communication from the parent
* to the child.
*/
fn spawn_listener<A: send>(+f: fn~(comm::port<A>)) -> comm::chan<A> {
let setup_po = comm::port();
let setup_ch = comm::chan(setup_po);
Expand Down Expand Up @@ -346,182 +390,6 @@ fn default_task_opts() -> task_opts {
}
}

fn builder() -> builder {
//! Construct a builder

let body_identity = fn@(+body: fn~()) -> fn~() { body };

builder_({
mut opts: default_task_opts(),
mut gen_body: body_identity,
can_not_copy: none
})
}

fn get_opts(builder: builder) -> task_opts {
//! Get the task_opts associated with a builder

builder.opts
}

fn set_opts(builder: builder, opts: task_opts) {
/*!
* Set the task_opts associated with a builder
*
* To update a single option use a pattern like the following:
*
* set_opts(builder, {
* linked: false
* with get_opts(builder)
* });
*/

builder.opts = opts;
}

fn set_sched_mode(builder: builder, mode: sched_mode) {
set_opts(builder, {
sched: some({
mode: mode,
foreign_stack_size: none
})
with get_opts(builder)
});
}

fn add_wrapper(builder: builder, gen_body: fn@(+fn~()) -> fn~()) {
/*!
* Add a wrapper to the body of the spawned task.
*
* Before the task is spawned it is passed through a 'body generator'
* function that may perform local setup operations as well as wrap
* the task body in remote setup operations. With this the behavior
* of tasks can be extended in simple ways.
*
* This function augments the current body generator with a new body
* generator by applying the task body which results from the
* existing body generator to the new body generator.
*/

let prev_gen_body = builder.gen_body;
builder.gen_body = fn@(+body: fn~()) -> fn~() {
gen_body(prev_gen_body(body))
};
}

fn run(-builder: builder, +f: fn~()) {
/*!
* Creates and exucutes a new child task
*
* Sets up a new task with its own call stack and schedules it to run
* the provided unique closure. The task has the properties and behavior
* specified by `builder`.
*
* # Failure
*
* When spawning into a new scheduler, the number of threads requested
* must be greater than zero.
*/

let body = builder.gen_body(f);
spawn_raw(builder.opts, body);
}


/* Builder convenience functions */

fn future_result(builder: builder) -> future::future<task_result> {
/*!
* Get a future representing the exit status of the task.
*
* Taking the value of the future will block until the child task
* terminates.
*
* Note that the future returning by this function is only useful for
* obtaining the value of the next task to be spawning with the
* builder. If additional tasks are spawned with the same builder
* then a new result future must be obtained prior to spawning each
* task.
*/

// FIXME (#1087, #1857): Once linked failure and notification are
// handled in the library, I can imagine implementing this by just
// registering an arbitrary number of task::on_exit handlers and
// sending out messages.

let po = comm::port();
let ch = comm::chan(po);

set_opts(builder, {
notify_chan: some(ch)
with get_opts(builder)
});

do future::from_fn {
alt comm::recv(po) {
exit(_, result) { result }
}
}
}

fn unsupervise(builder: builder) {
//! Configures the new task to not propagate failure to its parent

set_opts(builder, {
linked: false
with get_opts(builder)
});
}

fn run_with<A:send>(-builder: builder,
+arg: A,
+f: fn~(+A)) {

/*!
* Runs a task, while transfering ownership of one argument to the
* child.
*
* This is useful for transfering ownership of noncopyables to
* another task.
*
*/

let arg = ~mut some(arg);
do run(builder) {
let mut my_arg = none;
my_arg <-> *arg;
f(option::unwrap(my_arg))
}
}

fn run_listener<A:send>(-builder: builder,
+f: fn~(comm::port<A>)) -> comm::chan<A> {
/*!
* Runs a new task while providing a channel from the parent to the child
*
* Sets up a communication channel from the current task to the new
* child task, passes the port to child's body, and returns a channel
* linked to the port to the parent.
*
* This encapsulates some boilerplate handshaking logic that would
* otherwise be required to establish communication from the parent
* to the child.
*/

let setup_po = comm::port();
let setup_ch = comm::chan(setup_po);

do run(builder) {
let po = comm::port();
let mut ch = comm::chan(po);
comm::send(setup_ch, ch);
f(po);
}

comm::recv(setup_po)
}


/* Spawn convenience functions */

fn spawn(+f: fn~()) {
Expand All @@ -531,7 +399,7 @@ fn spawn(+f: fn~()) {
* Sets up a new task with its own call stack and schedules it to run
* the provided unique closure.
*
* This function is equivalent to `run(new_builder(), f)`.
* This function is equivalent to `task().spawn(f)`.
*/

task().spawn(f)
Expand Down Expand Up @@ -563,7 +431,7 @@ fn spawn_with<A:send>(+arg: A, +f: fn~(+A)) {
* This is useful for transfering ownership of noncopyables to
* another task.
*
* This function is equivalent to `run_with(builder(), arg, f)`.
* This function is equivalent to `task().spawn_with(arg, f)`.
*/

task().spawn_with(arg, f)
Expand Down Expand Up @@ -592,7 +460,7 @@ fn spawn_listener<A:send>(+f: fn~(comm::port<A>)) -> comm::chan<A> {
* };
* // Likewise, the parent has both a 'po' and 'ch'
*
* This function is equivalent to `run_listener(builder(), f)`.
* This function is equivalent to `task().spawn_listener(f)`.
*/

task().spawn_listener(f)
Expand Down

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